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  • 1.
    Aherne, Olivia
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. CR Competence, Naturvetarvägen 14, 223 62, Lund, Sweden.
    Ortiz, Roberto
    CR Competence, Naturvetarvägen 14, 223 62, Lund, Sweden.
    Fazli, Magnus M
    Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; SoftOx Solutions AS, Copenhagen, Denmark.
    Davies, Julia R
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Effects of stabilized hypochlorous acid on oral biofilm bacteria2022In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 22, no 1, article id 415Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Caries and periodontitis are amongst the most prevalent diseases worldwide, leading to pain and loss of oral function for those affected. Prevention relies heavily on mechanical removal of dental plaque biofilms but for populations where this is not achievable, alternative plaque control methods are required. With concerns over undesirable side-effects and potential bacterial resistance due to the use of chlorhexidine gluconate (CHX), new antimicrobial substances for oral use are greatly needed. Here we have investigated the antimicrobial effect of hypochlorous acid (HOCl), stabilized with acetic acid (HAc), on oral biofilms and compared it to that of CHX. Possible adverse effects of stabilized HOCl on hydroxyapatite surfaces were also examined.

    METHODS: Single- and mixed-species biofilms of six common oral bacteria (Streptococcus mutans, Streptococcus gordonii, Actinomyces odontolyticus, Veillonella parvula, Parvimonas micra and Porphyromonas gingivalis) within a flow-cell model were exposed to HOCl stabilized with 0.14% or 2% HAc, pH 4.6, as well as HOCl or HAc alone. Biofilm viability was assessed in situ using confocal laser scanning microscopy following LIVE/DEAD® BacLight™ staining. In-situ quartz crystal microbalance with dissipation (QCM-D) was used to study erosion of hydroxyapatite (HA) surfaces by stabilized HOCl.

    RESULTS: Low concentrations of HOCl (5 ppm), stabilized with 0.14% or 2% HAc, significantly reduced viability in multi-species biofilms representing supra- and sub-gingival oral communities, after 5 min, without causing erosion of HA surfaces. No equivalent antimicrobial effect was seen for CHX. Gram-positive and Gram-negative bacteria showed no significant differential suceptibility to stabilized HOCl.

    CONCLUSIONS: At low concentrations and with exposure times which could be achieved through oral rinsing, HOCl stabilized with HAc had a robust antimicrobial activity on oral biofilms, without causing erosion of HA surfaces or affecting viability of oral keratinocytes. This substance thus appears to offer potential for prevention and/or treatment of oral biofilm-mediated diseases.

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  • 2.
    Aidoukovitch, Alexandra
    et al.
    Lund University; Folktandvården Skåne.
    Bankell, Elisabeth
    Lund University.
    Davies, Julia R
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Nilsson, Bengt-Olof
    Lund University.
    Exogenous LL-37 but not homogenates of desquamated oral epithelial cells shows activity against Streptococcus mutans2021In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 79, no 6, p. 466-472Article in journal (Refereed)
    Abstract [en]

    Objective:  The antimicrobial peptide hCAP18/LL-37 is detected in desquamated epithelial cells of human whole saliva, but the functional importance of this pool of hCAP18/LL-37 is not understood. Here, we assess the impact of homogenates of desquamated oral epithelial cells and exogenous, synthetic LL-37 on two oral bacteria: S. mutans and S. gordonii.

    Material and methods:  Desquamated epithelial cells of unstimulated whole saliva were isolated and cellular and extracellular levels of hCAP18/LL-37 analyzed by ELISA. Bacterial viability was determined by BacLight Live/Dead staining and confocal laser scanning microscopy.

    Results:  Desquamated oral epithelial cells harboured hCAP18/LL-37, and they spontaneously released/leaked the peptide to their medium. Exogenous, synthetic LL-37 showed cytotoxic activity against S. mutans but not S gordonii, suggesting that LL-37 acts differentially on these two types of oral bacteria. Homogenates of desquamated oral epithelial cells had no effect on S. mutans viability. Treatment with exogenous, synthetic LL-37 (8 and 10 μM) reduced S. mutans viability, whereas lower concentrations (0.1 and 1 µM) of the peptide lacked effect.

    Conclusions:  Desquamated oral epithelial cells contain hCAP18/LL-37, but their cellular levels of hCAP18/LL-37 are too low to affect S. mutans viability, whereas exogenous, synthetic LL-37 has a strong effect on these bacteria.

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  • 3.
    Al Ansari, Yasmin
    et al.
    Malmö University, Faculty of Odontology (OD).
    Shahwan, Halime
    Malmö University, Faculty of Odontology (OD).
    Chrcanovic, Bruno Ramos
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis2022In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 15, no 9, article id 3227Article, review/survey (Refereed)
    Abstract [en]

    The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

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  • 4.
    Al Musawi, Ahmed
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Hellström, Lina
    Department of Medicine and Optometry, eHealth Institute, Linnaeus University, Kalmar; Pharmaceutical Department, Region Kalmar County, Kalmar.
    Axelsson, Malin
    Malmö University, Faculty of Health and Society (HS), Department of Care Science (VV).
    Midlöv, Patrik
    Department of Clinical Sciences Malmö, Center for Primary Health Care Research, Lund University.
    Rämgård, Margareta
    Malmö University, Faculty of Health and Society (HS), Department of Care Science (VV).
    Cheng, Yuanji
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Eriksson, Tommy
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Intervention for a correct medication list and medication use in older adults: a non-randomised feasibility study among inpatients and residents during care transitions2024In: International Journal of Clinical Pharmacy, ISSN 2210-7703, E-ISSN 2210-7711Article in journal (Refereed)
    Abstract [en]

    Background Medication discrepancies in care transitions and medication non-adherence are problematic. Few interventions consider the entire process, from the hospital to the patient’s medication use at home.

    Aim In preparation for randomised controlled trials (RCTs), this study aimed (1) to investigate the feasibility of recruitment and retention of patients and data collection to reduce medication discrepancies at discharge and improve medication adherence and (2) to explore the outcomes of the interventions.

    Method Participants were recruited from a hospital and a residential area. Hospital patients participated in a pharmacist-led intervention to establish a correct medication list upon discharge and a follow-up interview two weeks post-discharge. All participants received a person-centred adherence intervention for three to six months. Discrepancies in the medication lists, the Beliefs about Medicines Questionnaire (BMQ-S), and the Medication Adherence Report Scale (MARS-5) were assessed.

    Results Of 87 asked to participate, 35 were included, and 12 completed the study. Identifying discrepancies, discussing discrepancies with physicians, and performing follow-up interviews were possible. Conducting the adherence intervention was also possible using individual health plans for medication use. Among the seven hospital patients, 24 discrepancies were found. Discharging physicians agreed that all discrepancies were errors, but only ten were corrected in the discharge information. Ten participants decreased their total BMQ-S concern scores, and seven increased their total MARS-5 scores.

    Conclusion Based on this study, conducting the two RCTs separately may increase the inclusion rate. Data collection was feasible. Both interventions were feasible in many aspects but need to be optimised in upcoming RCTs.

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  • 5.
    Albrektsson, Tomas
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. Department of Biomaterials, University of Gothenburg, Sweden.
    Chrcanovic, Bruno
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Mölne, Johan
    Department of Pathology and Genetics, Sahlgrenska Academy, Sweden; University of Gothenburg, Sweden.
    Wennerberg, Ann
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. Department of Biomaterials, University of Gothenburg, Sweden.
    Foreign body reactions, marginal bone loss and allergies in relation to titanium implants2018In: European Journal of Oral Implantology, ISSN 1756-2406, E-ISSN 1756-2414, Vol. 11, no Suppl 1, p. S37-S46Article, review/survey (Refereed)
    Abstract [en]

    Aim: To describe general observations of immunological reactions to foreign materials and to realize that CP titanium gives rise to a foreign body reaction with subsequent bone embedment when placed as oral implants. To analyse the possibility of titanium allergy. Materials and methods: The present paper is of a narrative review type. Hand and Medline searches were performed to evaluate marginal bone loss of oral implants and the potential of titanium allergy. Results: Immunological reactions to foreign substances include Type I hypersensitivity reactions such as allergy, Type II hypersensitivity reactions characterised by IgM or IgG antibodies that may react with blood group antigens at transfusion, and Type III hypersensitivity caused by antigen-antibody immune complexes exemplified by acute serum sickness. There is also Type IV hypersensitivity, or delayed hypersensitivity, which is typically found in drug and foreign body reactions. It proved very difficult to find a universally acceptable definition of reasons for marginal bone loss around oral implants, which lead to most varying figures of so-called peri-implantitis being 1% to 2% in some 10-year follow-up papers to between 28% and 56% of all placed implants in other papers. It was recognised that bone resorption to oral as well as orthopaedic implants may be due to immunological reactions. Today, osseointegration is seen as an immune-modulated inflammatory process where the immune system is locally either up- or downregulated. Titanium implant allergy is a rare condition, if it exists. The authors found only two papers presenting strong evidence of allergy to CP titanium, but with the lack of universally accepted and tested patch tests, the precise diagnosis is difficult. Conclusions: CP titanium acts as a foreign body when placed in live tissues. There may be immunological reasons behind marginal bone loss. Titanium allergy may exist in rare cases, but there is a lack of properly designed and analysed patch tests at present.

  • 6.
    Albrektsson, Tomas
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. Univ Gothenburg, Dept Biomat, Gothenburg, Sweden.
    Dahlin, Christer
    NU Hosp Org, Dept Oral & Maxillofacial Surg ENT, Trollhattan, Sweden; Univ Gothenburg, Dept Biomat, Gothenburg, Sweden.
    Reinedahl, David
    Univ Gothenburg, Dept Prosthodont, Gothenburg, Sweden.
    Tengvall, Pentti
    Univ Gothenburg, Dept Biomat, Gothenburg, Sweden.
    Trindade, Ricardo
    Univ Gothenburg, Dept Prosthodont, Gothenburg, Sweden.
    Wennerberg, Ann
    Univ Gothenburg, Dept Prosthodont, Gothenburg, Sweden.
    An Imbalance of the Immune System Instead of a Disease Behind Marginal Bone Loss Around Oral Implants: Position Paper2020In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 35, no 3, p. 495-502Article in journal (Refereed)
    Abstract [en]

    Purpose: The purpose of this paper is to present evidence that supports the notion that the primary reason behind marginal bone loss and implant failure is immune-based and that bacterial actions in the great majority of problematic cases are of a secondary nature. Materials and Methods: The paper is written as a narrative review. Results: Evidence is presented that commercially pure titanium is not biologically inert, but instead activates the innate immune system of the body. For its function, the clinical implant is dependent on an immune/inflammatory defense against bacteria. Biologic models such as ligature studies have incorrectly assumed that the primary response causing marginal bone loss is due to bacterial action. In reality, bacterial actions are secondary to an imbalance of the innate immune system caused by the combination of titanium implants and ligatures, ie, nonself. This immunologic imbalance may lead to marginal bone resorption even in the absence of bacteria. Conclusion: Marginal bone loss and imminent oral implant failure cannot be properly analyzed without a clear understanding of immunologically caused tissue responses.

  • 7.
    Alenezi, Ali
    et al.
    Department of Prosthodontics, College of Dentistry, Qassim University, Buraydah 52571, Saudi Arabia.
    Alsweed, Mohammad
    Private Practice, Qassim Region, Buraydah 52571, Saudi Arabia.
    Alsidrani, Saleh
    Private Practice, Qassim Region, Buraydah 52571, Saudi Arabia.
    Chrcanovic, Bruno Ramos
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Long-Term Survival and Complication Rates of Porcelain Laminate Veneers in Clinical Studies: A Systematic Review2021In: Journal of Clinical Medicine, E-ISSN 2077-0383, Vol. 10, no 5, article id 1074Article in journal (Refereed)
    Abstract [en]

    The presented study aimed to assess the survival rate of porcelain laminate veneers (PLV) based on a systematic review of the literature. An electronic search was last updated in February 2021. Eligibility criteria included clinical series of patients rehabilitated with PLVs published in the last 25 years, with a minimum follow-up of 3 years. Survival analysis methods were applied. Twenty-five studies were included, with 6500 PLVs. The 10-year estimated cumulative survival rate (CSR) of PLVs was 95.5%. The 10-year CSR of PLVs when fracture, debonding, occurrence of secondary caries, and need of endodontic treatment were considered as isolated reasons for failure were 96.3%, 99.2%, 99.3%, and 99.0%, respectively. PLVs without incisal coverage had a higher failure rate than PLVs with incisal coverage. Non-feldspathic PLVs performed better than feldspathic PLVs. As a conclusion, the 10-year CSR of PLVs was 95.5%, when fracture, debonding, occurrence of secondary caries, and need of endodontic treatment were considered as reasons for restoration failure. Fracture seems to be most common complication of PLVs, followed by debonding, with both more commonly happening within the first years after PLV cementation. PLVs with incisal coverage and non-feldspathic PLVs presented lower failure rates than PLVs without incisal coverage and feldspathic PLVs.

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  • 8.
    Alenezi, Ali
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. Department of Prosthodontics, College of Dentistry, Qassim University, Buraidah, Saudi Arabia.
    Chrcanovic, Bruno
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Wennerberg, Ann
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Effects of Local Drug and Chemical Compound Delivery on Bone Regeneration Around Dental Implants in Animal Models: A Systematic Review and Meta-Analysis2018In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 33, no 1, p. e1-e18Article, review/survey (Refereed)
    Abstract [en]

    Purpose: One of the suggested methods for enhancing osseointegration is the local application of drug agents around implant surfaces. The aim of this review was to evaluate the methods most commonly used for local drug and chemical compound delivery to implant sites and assess their influence on osseointegration. Materials and Methods: An electronic search was undertaken in three databases (PubMed, Scopus, Embase). The search was limited to animal experiments using endosseous implants combined with local drug delivery systems. Meta-analyses were performed for the outcome bone-to-implant contact (BIC). Results: Sixty-one studies met the inclusion criteria. Calcium phosphate (CaP), bisphosphonates (BPs), and bone morphogenetic proteins (BMPs) were the most commonly used chemical compounds. There were two main methods for local drug delivery at the bone-implant interface: (1) directly from an implant surface by coating or immobilizing techniques, and (2) the local application of drugs to the implant site, using carriers. There was a statistically significant increase in BIC for both local drug delivery methods (P = .02 and P < .0001, respectively) compared with the control methods. There was a statistically significant increase in BIC when CaP (P = .0001) and BMPs (P = .02) were either coating implants or were delivered to the implant site, in comparison to when drugs were not used. The difference was not significant for the use of BPs (P = .15). Conclusion: It is suggested that the use of local chemical compound delivery systems around implants could significantly improve implant osseointegration in animal models. It is a matter of debate whether these in vivo results might have some significant effect in the human clinical setting in the long term.

  • 9.
    Alenezi, Ali
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. Department of Prosthodontics, College of Dentistry, Qassim University, Buraidah, Saudi Arabia.
    Galli, Silvia
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Atefyekta, Saba
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Andersson, Martin
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Wennerberg, Ann
    Department of Prosthodontics/Dental Materials Science, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
    Osseointegration effects of local release of strontium ranelate from implant surfaces in rats2019In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 30, no 10, article id 116Article in journal (Refereed)
    Abstract [en]

    Background: Numerous studies have reported the beneficial effects of strontium on bone growth, particularly by stimulating osteoblast proliferation and differentiation. Thus, strontium release around implants has been suggested as one possible strategy to enhance implant osseointegration. Aim: This study aimed to evaluate whether the local release of strontium ranelate (Sr-ranelate) from implants coated with mesoporous titania could improve bone formation around implants in an animal model. Materials and methods: Mesoporous titania (MT) thin coatings were formed utilizing the evaporation induced self-assembly (EISA) method using Pluronic (P123) with or without the addition of poly propylene glycol (PPG) to create materials with two different pore sizes. The MT was deposited on disks and mini-screws, both made of cp Ti grade IV. Scanning electron microscopy (SEM) was performed to characterize the MT using a Leo Ultra55 FEG instrument (Zeiss, Oberkochen, Germany). The MT was loaded with Sr-ranelate using soaking and the drug uptake and release kinetics to and from the surfaces were evaluated using quartz crystal microbalance with dissipation monitoring (QCM-D) utilizing a Q-sense E4 instrument. For the in vivo experiment, 24 adult rats were analyzed at two time points of implant healing (2 and 6 weeks). Titanium implants shaped as mini screws were coated with MT films and divided into two groups; supplied with Sr-ranelate (test group) and without Sr-ranelate (control group). Four implants (both test and control) were inserted in the tibia of each rat. The in vivo study was evaluated using histomorphometric analyses of the implant/bone interphase using optical microscopy. Results: SEM images showed the successful formation of evenly distributed MT films covering the entire surface with pore sizes of 6 and 7.2 nm, respectively. The QCM-D analysis revealed an absorption of 3300 ng/cm2 of Sr-ranelate on the 7.2 nm MT, which was about 3 times more than the observed amount on the 6 nm MT (1200 ng/cm2). Both groups showed sustained release of Sr-ranelate from MT coated disks. The histomorphometric analysis revealed no significant differences in bone implant contact (BIC) and bone area (BA) between the implants with Sr-ranelate and implants in the control groups after 2 and 6 weeks of healing (BIC with a p-value of 0.43 after 2 weeks and 0.172 after 6 weeks; BA with a p-value of 0.503 after 2 weeks, and 0.088 after 6 weeks). The mean BIC and BA values within the same group showed significant increase among all groups between 2 and 6 weeks. Conclusion: This study could not confirm any positive effects of Sr-ranelate on implant osseointegration.

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  • 10.
    Ali, Abdullah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Speximo AB, Medicon Village, Lund.
    Ringstad, Lovisa
    RISE Research Institutes of Sweden, Bioeconomy and Health, Stockholm.
    Skedung, Lisa
    RISE Research Institutes of Sweden, Bioeconomy and Health, Stockholm.
    Falkman, Peter
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Wahlgren, Marie
    Food Technology, Engineering and Nutrition, Lund University.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Tactile friction of topical creams and emulsions: Friction measurements on excised skin and VitroSkin® using ForceBoard™.2022In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 615, article id 121502Article in journal (Refereed)
    Abstract [en]

    Tactile perception can be investigated through ex vivo friction measurements using a so-called ForceBoard™, providing objective assessments and savings in time and money, compared to a subjective human panel. In this work we aim to compare excised skin versus VitroSkin® as model substrates for tactile friction measurements. A further aim is to detect possible differences between traditional surfactant-based creams, and a particle-stabilized (Pickering) cream and investigate how the different substrates affect the results obtained. It was found that the difference in tactile friction between excised skin and VitroSkin® was small on untreated substrates. When topical creams were applied, the same trends were observed for both substrates, although the frictional variation over time relates to the difference in surface structure between the two substrates. The results also confirmed that there is a difference between starch-based Pickering formulations and surfactant-based creams after application, indicating that the latter is greasier than Pickering cream. It was also shown that the tactile friction of Pickering emulsions was consistently high even with high amounts of oil, indicating a non-greasy, and non-sticky formulation. The characteristics of starch-stabilized Pickering formulations make them promising candidates in the development of surfactant-free topical formulations with unique tactile properties.

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  • 11.
    Ali, Abdullah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Speximo AB, Medicon Village, SE-223 81 Lund, Sweden.
    Skedung, L
    RISE Research Institutes of Sweden, Bioeconomy and Health, Perception and Design, Stockholm, Sweden.
    Burleigh, S
    Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden.
    Lavant, Eva
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ringstad, L
    RISE Research Institutes of Sweden, Bioeconomy and Health, Perception and Design, Stockholm, Sweden.
    Andersson, CD
    Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
    Wahlgren, M
    Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Relationship between sensorial and physical characteristics of topical creams: a comparative study of effects of excipients2022In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 613, p. 1-12, article id 121370Article in journal (Refereed)
    Abstract [en]

    Rising consumer demands for safer, more natural, and sustainable topical products have led to increased interest in finding alternative excipients, while retaining functionality and cosmetic appeal. Particle-stabilized Pickering creams have emerged as possible alternatives to replace traditional surfactant-stabilized creams and are thus one of the focuses in this study. The aim of this paper was to study relationships between sensorial characteristics and physical properties to understand how different excipients affect these aspects, comparing one starch particle–stabilized and three surfactant-stabilized formulations. A human panel was used to evaluate sensorial perception, while physical properties were deduced by rheology and tactile friction, together with in vivo and ex vivo skin hydration measurements.

    The results show that sensorial attributes related to the application phase can be predicted with rheology, while afterfeel attributes can be predicted with tactile friction studies. Differences in rheological and sensory properties among surfactant-based creams could mainly be attributed to the type of emollients used, presence of thickeners and surfactant composition. Differences between surfactant-based creams and a Pickering cream were more evident in relation to the afterfeel perception. Presence of starch particles in the residual film on skin results in high tactile friction and low perception of residual coating, stickiness, greasiness, and slipperiness in sensorial afterfeel.

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  • 12.
    Ali, Abdullah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Wahlgren, Marie
    Food Technology, Engineering and Nutrition, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden.
    Pedersen, Lina
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Will a water gradient in oral mucosa affect transbuccal drug absorption?2018In: Journal of Drug Delivery Science and Technology, ISSN 1773-2247, Vol. 48, p. 338-345Article in journal (Refereed)
    Abstract [en]

    Formulations for buccal drug delivery often comprise polymers to facilitate mucoadhesion based on water sorption. The main objective of the current study was therefore to evaluate the effect of dehydration on drug uptake through oral mucosa. We have used diffusion cells with excised porcine mucosa to study uptake of three alternative drugs (i.e., Metronidazole, Benzydamine and Xylometazoline) together with polyethylene glycol (PEG) as the model polymer for adjusting water activity in the test solutions. Taking drug activity into account, we can conclude that addition of PEG results in a drug flux through mucosa that is about two times lower for Metronidazole and more than 40 times lower for Xylometazoline compared to that from a pure PBS-solution. However, for Benzydamine the uptake through mucosa was more or less the same, which could possibly be due to the high PEG-concentration (65 wt%) affecting the dissociation constant and thus the permeability. These results indicate that an increased water gradient may have the same limiting effect on permeability through oral mucosa as previously seen for skin. Thus, water gradient effects should be a factor to consider when developing buccal adhesive formulations.

  • 13.
    Ali, Abdullah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Wahlgren, Marie
    Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden.
    Rembratt-Svensson, Birgitta
    Bioglan AB, Malmö, Sweden.
    Daftani, Ameena
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Falkman, Peter
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Wollmer, Per
    Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Dehydration affects drug transport over nasal mucosa2019In: Drug Delivery, ISSN 1071-7544, E-ISSN 1521-0464, Vol. 26, no 1, p. 831-840Article in journal (Refereed)
    Abstract [en]

    Formulations for nasal drug delivery often rely on water sorption to adhere to the mucosa, which also causes a higher water gradient over the tissue and subsequent dehydration. The primary aim of this study was therefore to evaluate mucosal response to dehydration and resolve the hypothesis that mucoadhesion achieved through water sorption could also be a constraint for drug absorption via the nasal route. The effect of altering water activity of the vehicle on Xylometazoline HCl and Cr-EDTA uptake was studied separately using flow through diffusion cells and excised porcine mucosa. We have shown that a modest increase in the water gradient over mucosa induces a substantial decrease in drug uptake for both Xylometazoline HCl and Cr-EDTA. A similar result was obtained when comparing two different vehicles on the market; Nasoferm (Nordic Drugs, Sweden) and BLOX4 (Bioglan, Sweden). Mucoadhesion based on water sorption can slow down drug uptake in the nasal cavity. However, a clinical study is required to determine whether prolonged duration of the vehicle or preventing dehydration of the mucosa is the most important factor for improving bioavailability.

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  • 14.
    Ali, Amir
    et al.
    Malmö University, Faculty of Odontology (OD).
    Al Attar, Ammar
    Malmö University, Faculty of Odontology (OD).
    Chrcanovic, Bruno Ramos
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Frequency of Smoking and Marginal Bone Loss around Dental Implants: A Retrospective Matched-Control Study2023In: Journal of Clinical Medicine, E-ISSN 2077-0383, Vol. 12, no 4, article id 1386Article in journal (Refereed)
    Abstract [en]

    This dental record-based retrospective study aimed to compare the marginal bone loss (MBL) around dental implants in a group of smokers in relation to a matched group of non-smokers, with a special focus on five different frequencies of daily smoking (non-smokers, and frequency of 1-5, 6-10, 11-15, and 20 cig./day). Only implants with a minimum of 36 months of radiological follow-up were considered. Univariate linear regression models were used to compare MBL over time between 12 clinical covariates, after which a linear mixed-effects model was built. After matching of the patients, the study included 340 implants in 104 smokers, and 337 implants in 100 non-smokers. The results suggested that smoking degree (greater MBL for higher degrees of smoking), bruxism (greater MBL for bruxers), jaw (greater MBL in maxilla), prosthesis fixation (greater MBL for screw-retained prosthesis), and implant diameter (greater MBL for 3.75-4.10 mm) had a significant influence on MBL over time. There appears to be a positive correlation between the degree of smoking and the degree of MBL, meaning, the higher the degree of smoking, the greater the MBL. However, the difference is not apparent for different degrees of smoking when this is high, namely above 10 cigarettes per day.

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  • 15.
    Alshammari, Hatem
    et al.
    Malmö University, Faculty of Odontology (OD).
    Neilands, Jessica
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Stavropoulos, Andreas
    Malmö University, Faculty of Odontology (OD). University of Geneva, Switzerland.
    Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis2021In: Antibiotics, ISSN 0066-4774, E-ISSN 2079-6382, Vol. 10, no 2, article id 150Article in journal (Refereed)
    Abstract [en]

    Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis. 

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  • 16.
    Ambaw, Y. A.
    et al.
    Precision Medicine Translational Research Programme and Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore; SLING, Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore 119077, Singapore; Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, MA 02138, USA.
    Dahl, S. R.
    Department of Chemistry, University of Oslo, 0315 Oslo, Norway; Hormone Laboratory, Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway.
    Chen, Y.
    Department of Chemistry, University of Oslo, 0315 Oslo, Norway.
    Greibrokk, T.
    Department of Chemistry, University of Oslo, 0315 Oslo, Norway.
    Lundanes, E.
    Department of Chemistry, University of Oslo, 0315 Oslo, Norway.
    Lazraq, Issam
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Shinde, Sudhirkumar
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. School of Consciousness, Dr Vishwanath Karad Maharashtra Institute of Technology–World Peace University, Kothrud, Pune 411038, Maharashtra, India.
    Selvalatchmanan, J.
    Precision Medicine Translational Research Programme and Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore; SLING, Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore 119077, Singapore.
    Wenk, M. R.
    Precision Medicine Translational Research Programme and Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore; SLING, Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore 119077, Singapore.
    Sellergren, Börje
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Torta, F.
    Precision Medicine Translational Research Programme and Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore; SLING, Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore 119077, Singapore.
    Tailored polymer-based selective extraction of lipid mediators from biological samples2021In: Metabolites, ISSN 2218-1989, E-ISSN 2218-1989, Vol. 11, no 8, article id 539Article in journal (Refereed)
    Abstract [en]

    Lipid mediators, small molecules involved in regulating inflammation and its resolution, are a class of lipids of wide interest as their levels in blood and tissues may be used to monitor health and disease states or the effect of new treatments. These molecules are present at low levels in biological samples, and an enrichment step is often needed for their detection. We describe a rapid and selective method that uses new low-cost molecularly imprinted (MIP) and non-imprinted (NIP) polymeric sorbents for the extraction of lipid mediators from plasma and tissue samples. The extraction process was carried out in solid-phase extraction (SPE) cartridges, manually packed with the sorbents. After extraction, lipid mediators were quantified by liquid chromatography–tandem mass spectrometry (LC–MSMS). Various parameters affecting the extraction efficiency were evaluated to achieve optimal recovery and to reduce non-specific interactions. Preliminary tests showed that MIPs, designed using the prostaglandin biosynthetic precursor arachidonic acid, could effectively enrich prostaglandins and structurally related molecules. However, for other lipid mediators, MIP and NIP displayed comparable recoveries. Under optimized conditions, the recoveries of synthetic standards ranged from 62% to 100%. This new extraction method was applied to the determination of the lipid mediators concentration in human plasma and mouse tissues and compared to other methods based on commercially available cartridges. In general, the methods showed comparable performances. In terms of structural specificity, our newly synthesized materials accomplished better retention of prostaglandins (PGs), hydroxydocosahexaenoic acid (HDoHE), HEPE, hydroxyeicosatetraenoic acids (HETE), hydroxyeicosatrienoic acid (HETrE), and PUFA compounds, while the commercially available Strata-X showed a higher recovery for dihydroxyeicosatetraenoic acid (diHETrEs). In summary, our results suggest that this new material can be successfully implemented for the extraction of lipid mediators from biological samples. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

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  • 17.
    Andoralov, Victor
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
    Dergousova, Natalia
    Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
    Kulikova, Olga
    Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
    Popov, Vladimir
    Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; Kurchatov NBIC Centre, National Research Centre “Kurchatov Institute”, 123182 Moscow, Russia.
    Tikhonova, Tamara
    Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
    Octaheme nitrite reductase: The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction.2021In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 138, article id 107699Article in journal (Refereed)
    Abstract [en]

    Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.

  • 18.
    Angiolini, Lorenzo
    et al.
    Departamento de Química Física, Facultad de Ciencias del Medio Ambiente y Bioquímica and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain..
    Valetti, Sabrina
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Nanologica AB, Södertälje, SE-151 36, Sweden.
    Cohen, Boiko
    Departamento de Química Física, Facultad de Ciencias Del Medio Ambiente y Bioquímica, INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, Toledo, 45071, Spain.
    Feiler, Adam
    Nanologica AB, Södertälje, SE-151 36, Sweden; Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden.
    Douhal, Abderrazzak
    Departamento de Química Física, Facultad de Ciencias Del Medio Ambiente y Bioquímica, INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, Toledo, 45071, Spain.
    Fluorescence imaging of antibiotic clofazimine encapsulated within mesoporous silica particle carriers: relevance to drug delivery and the effect on its release kinetics2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 17, p. 11899-11911Article in journal (Refereed)
    Abstract [en]

    We report on the encapsulation of the antibiotic clofazimine (CLZ) within the pores of mesoporous silica particles having hydrophilic (CBET value of 137) and more hydrophobic (CBET value of 94 after calcination at 600 °C) surfaces. We studied the effect of pH on the released amount of CLZ in aqueous solutions and observed a maximum at pH 4.1 in correlation with the solubility of the drug. Less release of the drug was observed from the more hydrophobic particles which was attributed to a difference in the affinity of the drug to the carrier particles. Fluorescence lifetime imaging microscopy, emission spectra, and fluorescence lifetimes of single drug loaded particles provided detailed understanding and new knowledge of the physical form of the encapsulated drug and the distribution within the particles. The distribution of CLZ within the particles was independent of the surface chemistry of the particles. The confirmation of CLZ molecules as monomers or aggregates was revealed by controlled removal of the drug with solvent. Additionally, the observed optical "halo effect" in the fluorescent images was interpreted in terms of specific quenching of high concentration of molecules. The emission lifetime experiments suggest stronger interaction of CLZ with the more hydrophobic particles, which is relevant to its release. The results reported in this work demonstrate that tuning the hydrophilicity/hydrophobicity of mesoporous silica particles can be used as a tool to control the release without impacting their loading ability.

  • 19.
    Argatov, Ivan
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Chongqing University, People’s Republic of China.
    Controlling the adhesive pull-off force via the change of contact geometry2021In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 379, no 2203, article id 20200392Article in journal (Refereed)
    Abstract [en]

    A first-order asymptotic analysis of the Griffith energy balance in the Johnson-Kendall-Roberts model of adhesive contact under non-symmetric perturbation of the contact geometry is presented. The pull-off force is evaluated in explicit form. A particular case of adhesive contact between a relatively stiff sphere and an elastic half-space is considered under the assumption that the sphere geometry is changed by the application of an arbitrary lateral normal surface loading. The effect of the sphere Poisson's ratio on controlling the adhesive pull-off force is considered.

    This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.

  • 20.
    Argatov, Ivan
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Institut für Mechanik, Technische Universität Berlin, 10623 Berlin, Germany.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Modeling of composite sorption isotherm for stratum corneum2022In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1864, no 7, p. 1-8, article id 183910Article in journal (Refereed)
    Abstract [en]

    Equilibrium water sorption in stratum corneum (SC) is considered by treating it as a biocomposite with two main phases, namely, corneocytes and lipids. To validate the rule of mixtures for the individual phase sorption isotherms, a new flexible fitting model is introduced by accounting for characteristic features observed in the variations of the thermodynamic correction factors corresponding to the individual sorption isotherms. The comparison of the model fitting performance with that of the five-parameter Park's model shows a remarkably good ability to fit experimental data for different types of sorption isotherms. The effect of the lipids content on the variance of the composite sorption isotherm of stratum corneum is highlighted. The sensitivity analysis reveals that for the typical water content 20-30 wt%, which corresponds to the SC in a stable condition, the sensitivity of the composite sorption isotherm to the variation of the lipids content on dry basis is predominantly positive and sufficiently small. The good agreement observed between the experimental sorption isotherm for SC and the composite isotherm, which is based on the rule of mixtures for the individual phase sorption isotherms, yields a plausible conclusion (hypothesis) that the corneocytes-lipids mechanical interaction during unconstrained swelling of the SC membrane in the in vitro laboratory experiment is negligible.

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  • 21.
    Argatov, Ivan I
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Malmö University, Biofilms Research Center for Biointerfaces. Technische Universität Berlin.
    Indentation mapping of stretched adhesive membranes2021In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences, ISSN 1364-5021, E-ISSN 1471-2946, Vol. 477, no 2251, article id 20210349Article in journal (Refereed)
    Abstract [en]

    Unilateral adhesive contact between a rigid indenter and a uniformly stretched membrane of arbitrary shape is considered. The generalized Johnson-Kendall-Roberts (JKR)-type and Derjaguin- Muller-Toporov (DMT)-type models of non-axisymmetric adhesive contact are presented for short- and long-range adhesion, respectively, and the JKR-DMT transition is established in the framework of the generalized Maugis-Dugdale model. A refined method of matched asymptotic expansions is applied to construct the leading-order asymptotic model for indentation mapping of freestanding two-dimensional materials with an axisymmetric probe, using the approximate analytical solution obtained in explicit form for an infinite membrane in the limit of short-range adhesive contact with an indenter in the form of an elliptic paraboloid. The cases of a spherical indenter and a rectangular membrane are studied in detail.

  • 22.
    Argatov, Ivan
    et al.
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Malmö University, Biofilms Research Center for Biointerfaces. Institut für Mechanik Technische Universität Berlin, Berlin 10623 Germany.
    Jin, Xiaoqing
    College of Aerospace Engineering, Chongqing University, Chongqing, 400030, China.
    Gravitational settling of a cell on a high-aspect-ratio nanostructured substrate: An asymptotic modeling approach2022In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 108, p. 294-307Article in journal (Refereed)
    Abstract [en]

    The problem of contact deformation of an elastic body loaded by gravitational forces and laying on several small rigid supports is considered in the framework of the linear theory of elasticity. Using the method of matched asymptotic expansions, the limit asymptotic model for determining the support reactions and the kinematic parameters of the body settling is derived. The effect of the body surface reinforcement is discussed. The case of a uniform (symmetric) settling is considered in detail.

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  • 23.
    Argatov, Ivan
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    A note on artificial neural network modeling of vapor-liquid equilibrium in multicomponent mixtures2019In: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 502, article id 112282Article in journal (Refereed)
    Abstract [en]

    Application of artificial neural networks (ANNs) for modeling of vapor-liquid equilibrium in multicomponent mixtures is considered. Two novel ANN-based models are introduced, which can be seen as generalizations of the Wilson model and the NRTL model. A unique feature of the proposed approach is that an ANN approximation for the molar excess Gibbs energy generates approximations for the activity coefficients. A special case of the ternary acetic acid-n-propyl alcohol-water system (at 313.15 K) is used to illustrate the efficiency of the different models, including Wilson's model, Focke's model, and the introduced generalized degree-1 homogeneous neural network model. Also, the latter one-level NN model is compared to the Wilson model on 10 binary systems. The efficiency of the two-level NN model is assessed by a comparison with the NRTL model. (C) 2019 Elsevier B.V. All rights reserved.

  • 24.
    Argatov, Ivan
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Chongqing University, China.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    An empirical model for sorption by glassy polymers: An assessment of thermodynamic parameters2021In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 99Article in journal (Refereed)
    Abstract [en]

    A new fitting model for sorption by glassy polymers is suggested based on the Flory–Huggins (FH) equation with a composite formula for the FH interaction parameter, χ, which is applicable if sorption experimental data shows a single-maximum variation of the FH parameter. Namely, a power-like and a linear approximation is assumed for χ(φ1), as a function of solvent volume fraction φ1, before and after the point of its maximum. After determining the maximum point from a direct inspection of the sorption data, the three fitting parameters are evaluated by solving two independent least-square minimization problems. Several sorption studies of biopolymers taken from the literature show that the endset of the glass transition region is correlated with the position of the maximum of the FH interaction parameter. Based on this hypothesis and the Vrentas–Vrentas model for sorption of glassy polymers, a theoretical framework for the glass transition analysis is developed. In particular, the solvent-induced glass transition temperature variation can be estimated from the sorption isotherm as a function of the solvent content corresponding to temperatures above the temperature of sorption.

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  • 25.
    Argatov, Ivan
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Tech Univ Berlin, Inst Mech, Berlin, Germany.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Analysis of the minimal model for the enthalpy relaxation and recovery in glass transition: application to constant-rate differential scanning calorimetry2021In: Continuum Mechanics and Thermodynamics, ISSN 0935-1175, E-ISSN 1432-0959, Vol. 33, p. 107-123Article in journal (Refereed)
    Abstract [en]

    The so-called minimal model is formulated for describing the enthalpy relaxation and recovery in glass transition. The model is based on the Arrhenius law for the enthalpy relaxation, which uses two-dimensional parameters, namely the activation energy and the so-called pre-factor (relaxation time at relatively high temperature). A numerically effective exact analytical solution is obtained for the case of constant-rate differential scanning calorimetry. The developed model is analyzed according to the logic of the model itself without introducing additional simplifying assumptions of thermodynamic nature. For typical range of the model parameters, the resulting differential equation contains a large parameter, which offers an opportunity for the application of asymptotic and approximate techniques. A number of simple approximations have been provided for some thermodynamic quantities of interest.

  • 26.
    Argatov, Ivan
    et al.
    Tech Univ Berlin, Inst Mech, D-10623 Berlin, Germany..
    Krcic, Nedim
    Magle Chemoswed, Agneslundsvagen 27, SE-21215 Malmö, Sweden..
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Sedimentation of a starch microsphere: What is usually missed and why?2023In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 10, article id e20257Article in journal (Refereed)
    Abstract [en]

    Gravimetric sedimentation is known as a relatively simple method of determining density of spherical particles. When the method is applied to water-swollen starch microparticles of about submillimeter sizes, it becomes evident that a careful selection of the experimental setup parameters is needed for producing accurate testing results. The main reason for this is that the mean particle density is very close to the density of water, and therefore, a dynamic model accounting for the so-called Bassett history force should be employed for describing the unsteady accelerating particle settling. A main novelty of this study consists in deriving a priori estimates for the settling time and distance.

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  • 27.
    Argatov, Ivan
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Papangelo, A.
    Department of Mechanics, Mathematics and Management, Politecnico di Bari, Via Orabona 4, Bari 70125, Italy; Hamburg University of Technology, Department of Mechanical Engineering, Am Schwarzenberg-Campus 1, Hamburg 21073, Germany.
    Ciavarella, M.
    Department of Mechanics, Mathematics and Management, Politecnico di Bari, Via Orabona 4, Bari 70125, Italy; Hamburg University of Technology, Department of Mechanical Engineering, Am Schwarzenberg-Campus 1, Hamburg 21073, Germany.
    Elliptical adhesive contact under biaxial stretching2020In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences, ISSN 1364-5021, E-ISSN 1471-2946, Vol. 476, no 2233, article id 20190507Article in journal (Refereed)
    Abstract [en]

    Adhesive contact of the Hertzian indenter with an incompressible elastic substrate bi-directionally stretched along the indenter principal planes of curvature is considered in the Johnson-Kendall-Roberts theoretical framework. An approximate model is constructed by examining energy release rate conditions only on the edges of the minor and major axes of the contact ellipse. The effect of weak coupling between fracture modes I and II is introduced using a phenomenological mode-mixity function. This study was motivated by the need to model a passive-adhesive mechanism in cell mechanics on stretchable substrates.

  • 28.
    Argatov, Ivan
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Tech Univ Berlin, Inst Mech, D-10623 Berlin, Germany..
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Dynamics of post-occlusion water diffusion in stratum corneum2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 17957Article in journal (Refereed)
    Abstract [en]

    Diffusion of water through membranes presents a considerable challenge, as the diffusivity often depends on the local concentration of water. One particular example with strong biological relevance is the stratum corneum (SC) as the primary permeability barrier for the skin. A simple alternative for the constant diffusivity model is provided by the Fujita's two-parameter rational approximation, which captures the experimentally observed fact that the SC diffusion constant for water increases with increasing the water concentration. Based on Fick's law of diffusion, a one-dimensional concentration-dependent diffusion model is developed and applied for the analysis of both the steady-state transepidermal water loss (TEWL) and the non-steady-state so-called skin surface water loss (SSWL) occurred after removal of an occlusion patch from the SC surface. It is shown that some of the age-related changes in the SSWL can be qualitatively explained by the variation of the dimensionless Fujita concentration-dependence parameter.

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  • 29.
    Bahmanzadeh, Safiyeh
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Analytical Research Laboratory, Department of Chemistry, University of Sistan and Baluchestan, P.O. Box 98135-674, Zahedan, Iran.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Sotres, Javier
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Proteolytic degradation of gelatin-tannic acid multilayers2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 526, p. 244-252Article in journal (Refereed)
    Abstract [en]

    Hypothesis Gelatin is one of the most popular constituents of biodegradable/edible films. Because of its poor mechanical properties, it typically needs to be cross-linked. In this regard, the use of tannic acid has attracted significant interest. Whereas the biodegradability of gelatin is well established, little is known on how different crosslinking methods affect biodegradability. In most cases, the ionic strength at which protein films are grown has a drastic effect on their structure. Thus, it is expected that by controlling the ionic strength during the growth of cross-linked gelatin films it should be possible to tune the access to relevant cleavage sites by proteases and, therefore, their biodegradability. Experiments Gelatin-tannic acid were grown at different ionic strengths by means of the layer-by-layer self-assembly method. The growth of these multilayers and their response to the presence of different proteases were monitored by means of Electrochemical Impedance Spectroscopy and Quartz Crystal Microbalance with Dissipation. Findings Gelatin-tannic acid multilayers grown at low ionic strength exhibited a swollen structure that allowed easy access to their cleavage sites by proteases. Multilayers formed at physiological ionic strength exhibited a compacter structure, which limited their proteolytic degradation.

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  • 30.
    Barrat, Jean-Louis
    et al.
    Univ Grenoble Alpes, CNRS, LIPhy, Grenoble, France..
    Del Gado, Emanuela
    Georgetown Univ, Inst Soft Matter Synth & Metrol, Dept Phys, Washington, DC 20057 USA..
    Egelhaaf, Stefan U.
    Heinrich Heine Univ, Condensed Matter Phys Lab, D-40225 Dusseldorf, Germany..
    Mao, Xiaoming
    Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA..
    Dijkstra, Marjolein
    Univ Utrecht, Debye Inst Nanomat Sci, Soft Condensed Matter, Utrecht, Netherlands..
    Pine, David J.
    NYU, Dept Phys, New York, NY USA.;NYU, Dept Chem & Biol Engn, New York, NY USA..
    Kumar, Sanat K.
    Columbia Univ, Dept Chem Engn, Soft Matter Grp, New York, NY USA..
    Bishop, Kyle
    Columbia Univ, Dept Chem Engn, Soft Matter Grp, New York, NY USA..
    Gang, Oleg
    Columbia Univ, Dept Chem Engn, Soft Matter Grp, New York, NY USA..
    Obermeyer, Allie
    Columbia Univ, Dept Chem Engn, Soft Matter Grp, New York, NY USA..
    Papadakis, Christine M.
    Tech Univ Munich, Dept Phys, Soft Matter Phys Grp, James Franck Str 1, D-85748 Garching, Germany..
    Tsitsilianis, Constantinos
    Univ Patras, Dept Chem Engn, Patras 26500, Greece..
    Smalyukh, Ivan I.
    Univ Colorado, Dept Phys, Boulder, CO 80309 USA.;Univ Colorado, Mat Sci Engn Program, Boulder, CO 80309 USA.;Natl Renewable Energy Lab, Renewable & Sustainable Energy Inst, Boulder, CO 80309 USA.;Univ Colorado, Boulder, CO 80309 USA..
    Hourlier-Fargette, Aurelie
    Univ Strasbourg, Inst Charles Sadron, CNRS, UPR22, Strasbourg, France..
    Andrieux, Sebastien
    Univ Strasbourg, Inst Charles Sadron, CNRS, UPR22, Strasbourg, France..
    Drenckhan, Wiebke
    Univ Strasbourg, Inst Charles Sadron, CNRS, UPR22, Strasbourg, France..
    Wagner, Norman
    Univ Delaware, Ctr Neutron Sci, Dept Chem & Biomol Engn, Newark, DE 19716 USA..
    Murphy, Ryan P.
    NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA..
    Weeks, Eric R.
    Emory Univ, Atlanta, GA 30322 USA..
    Cerbino, Roberto
    Univ Vienna, A-1090 Vienna, Austria..
    Han, Yilong
    Hong Kong Univ Sci & Technol, Dept Phys, Hong Kong, Peoples R China..
    Cipelletti, Luca
    Univ Montpellier, CNRS, Lab Charles Coulomb L2C, Montpellier, France.;Inst Univ France IUF, Montpellier, France..
    Ramos, Laurence
    Univ Montpellier, CNRS, Lab Charles Coulomb L2C, Montpellier, France..
    Poon, Wilson C. K.
    Univ Edinburgh, Sch Phys & Astron, Edinburgh Complex Fluids Partnership, James Clerk Maxwell Bldg,Kings Bldg, Edinburgh EH9 3JZ, Midlothian, Scotland..
    Richards, James A.
    Univ Edinburgh, Sch Phys & Astron, Edinburgh Complex Fluids Partnership, James Clerk Maxwell Bldg,Kings Bldg, Edinburgh EH9 3JZ, Midlothian, Scotland..
    Cohen, Itai
    Cornell Univ, Dept Phys, Ithaca, NY 14853 USA..
    Furst, Eric M.
    Univ Delaware, Dept Chem & Biomol Engn, Newark, DE USA..
    Nelson, Alshakim
    Univ Washington, Dept Chem, Seattle, WA 98195 USA..
    Craig, Stephen L.
    Duke Univ, Dept Chem, Durham, NC 27706 USA..
    Ganapathy, Rajesh
    Jawaharlal Nehru Ctr Adv Sci Res, Bangalore 560064, Karnataka, India..
    Sood, Ajay Kumar
    Indian Inst Sci, Bangalore 560012, Karnataka, India..
    Sciortino, Francesco
    Sapienza Univ Roma, Dept Phys, Piazzale Aldo Moro 5, I-00185 Rome, Italy..
    Mungan, Muhittin
    Univ Cologne, Inst Biol Phys, Zulpicher Str 77, D-50937 Cologne, Germany.;Univ Bonn, Inst Appl Math, Endenicher Allee 60, D-53115 Bonn, Germany..
    Sastry, Srikanth
    Jawaharlal Nehru Ctr Adv Sci Res, Jakkar Campus, Bengaluru 560064, India..
    Scheibner, Colin
    Univ Chicago, James Franck Inst, Chicago, IL 60637 USA.;Univ Chicago, Dept Phys, Chicago, IL 60637 USA..
    Fruchart, Michel
    Univ Chicago, James Franck Inst, Chicago, IL 60637 USA.;Univ Chicago, Dept Phys, Chicago, IL 60637 USA..
    Vitelli, Vincenzo
    Univ Chicago, James Franck Inst, Chicago, IL 60637 USA.;Univ Chicago, Dept Phys, Chicago, IL 60637 USA.;Univ Chicago, Kadanoff Ctr Theoret Phys, Chicago, IL 60637 USA..
    Ridout, S. A.
    Univ Penn, Dept Phys, Philadelphia, PA 19104 USA.;Emory Univ, Dept Phys, Atlanta, GA 30322 USA..
    Stern, M.
    Univ Penn, Dept Phys, Philadelphia, PA 19104 USA..
    Tah, I
    Univ Penn, Dept Phys, Philadelphia, PA 19104 USA.;CSIR Cent Glass & Ceram Res Inst, Special Glass Div, Kolkata 700032, India..
    Zhang, G.
    Univ Penn, Dept Phys, Philadelphia, PA 19104 USA.;City Univ Hong Kong, Dept Phys, Kowloon Tong, 83 Tat Chee Ave, Hong Kong, Peoples R China..
    Liu, Andrea J.
    Univ Penn, Dept Phys, Philadelphia, PA 19104 USA.;Simons Fdn, Flatiron Inst, New York, NY 10010 USA..
    Osuji, Chinedum O.
    Univ Penn, Dept Chem & Biomol Engn, Philadelphia, PA 19104 USA..
    Xu, Yuan
    Univ Queensland, Sch Chem Engn, Brisbane, Qld, Australia..
    Shewan, Heather M.
    Univ Queensland, Sch Chem Engn, Brisbane, Qld, Australia..
    Stokes, Jason R.
    Univ Queensland, Sch Chem Engn, Brisbane, Qld, Australia..
    Merkel, Matthias
    Univ Toulon & Var, Aix Marseille Univ, Turing Ctr Living Syst CENTURI, CPT,CNRS,UMR 7332, F-13288 Marseille, France..
    Ronceray, Pierre
    Aix Marseille Univ, Turing Ctr Living Syst CENTURI, CNRS, CINaM,UMR 7325, Marseille, France..
    Rupprecht, Jean-Francois
    Univ Toulon & Var, Aix Marseille Univ, Turing Ctr Living Syst CENTURI, CPT,CNRS,UMR 7332, F-13288 Marseille, France..
    Matsarskaia, Olga
    Inst Laue Langevin, Grenoble, France..
    Schreiber, Frank
    Univ Tubingen, Inst Appl Phys, Tubingen, Germany..
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Aubin-Tam, Marie-Eve
    Delft Univ Technol, Kavli Inst Nanosci, Dept Bionanosci, NL-2629 HZ Delft, Netherlands..
    Koenderink, Gijsje H.
    Delft Univ Technol, Kavli Inst Nanosci, Dept Bionanosci, NL-2629 HZ Delft, Netherlands..
    Espinosa-Marzal, Rosa M.
    Univ Illinois, Urbana, IL USA..
    Yus, Joaquin
    Univ Illinois, Urbana, IL USA..
    Kwon, Jiheon
    Univ Illinois, Urbana, IL USA..
    Soft matter roadmap2024In: Journal of Physics: Materials, E-ISSN 2515-7639, Vol. 7, no 1, article id 012501Article, review/survey (Refereed)
    Abstract [en]

    Soft materials are usually defined as materials made of mesoscopic entities, often self-organised, sensitive to thermal fluctuations and to weak perturbations. Archetypal examples are colloids, polymers, amphiphiles, liquid crystals, foams. The importance of soft materials in everyday commodity products, as well as in technological applications, is enormous, and controlling or improving their properties is the focus of many efforts. From a fundamental perspective, the possibility of manipulating soft material properties, by tuning interactions between constituents and by applying external perturbations, gives rise to an almost unlimited variety in physical properties. Together with the relative ease to observe and characterise them, this renders soft matter systems powerful model systems to investigate statistical physics phenomena, many of them relevant as well to hard condensed matter systems. Understanding the emerging properties from mesoscale constituents still poses enormous challenges, which have stimulated a wealth of new experimental approaches, including the synthesis of new systems with, e.g. tailored self-assembling properties, or novel experimental techniques in imaging, scattering or rheology. Theoretical and numerical methods, and coarse-grained models, have become central to predict physical properties of soft materials, while computational approaches that also use machine learning tools are playing a progressively major role in many investigations. This Roadmap intends to give a broad overview of recent and possible future activities in the field of soft materials, with experts covering various developments and challenges in material synthesis and characterisation, instrumental, simulation and theoretical methods as well as general concepts.

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  • 31.
    Barriga, Hanna
    et al.
    Department of Medical Biochemistry and Biophysics, Karolinska Institutet Stockholm, Sweden.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Hall, Stephen
    Division of Solid Mechanics, Lund University, and Lund Institute of Advanced Neutron and X-ray Science, Lund, Sweden.
    Hellsing, Maja
    Division for Bioeconomy and Health, RISE Research Institutes of Sweden, Stockholm, Sweden.
    Karlsson, Maths
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Pavan, Adriano
    Department of Chemistry, Uppsala University, Uppsala, Sweden.
    Peng, Ru
    Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Strandqvist, Nanny
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Wolff, Max
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    A Bibliometric Study on Swedish Neutron Users for the Period 2006–20202021In: Neutron News, ISSN 1044-8632, E-ISSN 1931-7352, Vol. 32, no 4, p. 28-33Article in journal (Refereed)
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  • 32.
    Beck, Christian
    et al.
    Univ Tubingen, Inst Angew Phys, Morgenstelle 10, D-72076 Tubingen, Germany.;Inst Max von Laue Paul Langevin, 71 Ave Martyrs, F-38042 Grenoble, France..
    Grimaldo, Marco
    Inst Max von Laue Paul Langevin, 71 Ave Martyrs, F-38042 Grenoble, France..
    Braun, Michal K.
    Univ Tubingen, Inst Angew Phys, Morgenstelle 10, D-72076 Tubingen, Germany..
    Buhl, Lena
    Univ Tubingen, Inst Angew Phys, Morgenstelle 10, D-72076 Tubingen, Germany..
    Matsarskaia, Olga
    Inst Max von Laue Paul Langevin, 71 Ave Martyrs, F-38042 Grenoble, France..
    Jalarvo, Niina H.
    Forschungszentrum Julich, Julich Ctr Neutron Sci JCNS, D-52425 Julich, Germany.;Oak Ridge Natl Lab, Chem & Engn Mat Div, Neutron Sci Directorate, POB 2008, Oak Ridge, TN 37831 USA.;Oak Ridge Natl Lab, JCNS Outstn Spallat Neutron Source SNS, POB 2008, Oak Ridge, TN 37831 USA..
    Zhang, Fajun
    Univ Tubingen, Inst Angew Phys, Morgenstelle 10, D-72076 Tubingen, Germany..
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Lund Univ, Div Phys Chem, Nat Vetarvagen 14, S-22100 Lund, Sweden..
    Schreiber, Frank
    Univ Tubingen, Inst Angew Phys, Morgenstelle 10, D-72076 Tubingen, Germany..
    Seydel, Tilo
    Inst Max von Laue Paul Langevin, 71 Ave Martyrs, F-38042 Grenoble, France..
    Temperature and salt controlled tuning of protein clusters2021In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, no 37, p. 8506-8516Article in journal (Refereed)
    Abstract [en]

    The formation of molecular assemblies in protein solutions is of strong interest both from a fundamental viewpoint and for biomedical applications. While ordered and desired protein assemblies are indispensable for some biological functions, undesired protein condensation can induce serious diseases. As a common cofactor, the presence of salt ions is essential for some biological processes involving proteins, and in aqueous suspensions of proteins can also give rise to complex phase diagrams including homogeneous solutions, large aggregates, and dissolution regimes. Here, we systematically study the cluster formation approaching the phase separation in aqueous solutions of the globular protein BSA as a function of temperature (T), the protein concentration (c(p)) and the concentrations of the trivalent salts YCl3 and LaCl3 (c(s)). As an important complement to structural, i.e. time-averaged, techniques we employ a dynamical technique that can detect clusters even when they are transient on the order of a few nanoseconds. By employing incoherent neutron spectroscopy, we unambiguously determine the short-time self-diffusion of the protein clusters depending on c(p), c(s) and T. We determine the cluster size in terms of effective hydrodynamic radii as manifested by the cluster center-of-mass diffusion coefficients D. For both salts, we find a simple functional form D(c(p), c(s), T) in the parameter range explored. The calculated inter-particle attraction strength, determined from the microscopic and short-time diffusive properties of the samples, increases with salt concentration and temperature in the regime investigated and can be linked to the macroscopic behavior of the samples.

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  • 33.
    Beck, Christian
    et al.
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany; Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France.
    Grimaldo, Marco
    Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France.
    Lopez, Hender
    School of Physics and Optometric & Clinical Sciences, Technological University Dublin, D07 XT95 Grangegorman, Ireland.
    Da Vela, Stefano
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
    Sohmen, Benedikt
    Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany.
    Zhang, Fajun
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
    Oettel, Martin
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
    Barrat, Jean-Louis
    Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France.
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Schreiber, Frank
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
    Seydel, Tilo
    Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France.
    Short-Time Transport Properties of Bidisperse Suspensions of Immunoglobulins and Serum Albumins Consistent with a Colloid Physics Picture.2022In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 126, no 38, p. 7400-7408Article in journal (Refereed)
    Abstract [en]

    The crowded environment of biological systems such as the interior of living cells is occupied by macromolecules with a broad size distribution. This situation of polydispersity might influence the dependence of the diffusive dynamics of a given tracer macromolecule in a monodisperse solution on its hydrodynamic size and on the volume fraction. The resulting size dependence of diffusive transport crucially influences the function of a living cell. Here, we investigate a simplified model system consisting of two constituents in aqueous solution, namely, of the proteins bovine serum albumin (BSA) and bovine polyclonal gamma-globulin (Ig), systematically depending on the total volume fraction and ratio of these constituents. From high-resolution quasi-elastic neutron spectroscopy, the separate apparent short-time diffusion coefficients for BSA and Ig in the mixture are extracted, which show substantial deviations from the diffusion coefficients measured in monodisperse solutions at the same total volume fraction. These deviations can be modeled quantitatively using results from the short-time rotational and translational diffusion in a two-component hard sphere system with two distinct, effective hydrodynamic radii. Thus, we find that a simple colloid picture well describes short-time diffusion in binary mixtures as a function of the mixing ratio and the total volume fraction. Notably, the self-diffusion of the smaller protein BSA in the mixture is faster than the diffusion in a pure BSA solution, whereas the self-diffusion of Ig in the mixture is slower than in the pure Ig solution.

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  • 34.
    Beck, Christian
    et al.
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany; Institut Max von Laue Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France..
    Pounot, Kevin
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany; Institut Max von Laue Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France..
    Mosca, Ilaria
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany; Institut Max von Laue Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France..
    H Jalarvo, Niina
    Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany; Chemical and Engineering Materials Division, Neutron Sciences Directorate, and JCNS Outstation at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, USA.
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Schreiber, Frank
    Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
    Seydel, Tilo
    Institut Max von Laue Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France.
    Notes on Fitting and Analysis Frameworks for QENS Spectra of (Soft) Colloid Suspensions2022In: EPJ Web of Conferences, E-ISSN 2100-014X, Vol. 272, p. 01004-01004Article in journal (Refereed)
    Abstract [en]

    With continuously improving signal-to-noise ratios, a statistically sound analysis of quasi-elasticneutron scattering (QENS) spectra requires to fit increasingly complex models which poses several challenges.Simultaneous fits of the spectra for all recorded values of the momentum transfer become a standard approach.Spectrometers at spallation sources can have a complicated non-Gaussian resolution function which has to bedescribed most accurately. At the same time, to speed up the fitting, an analytical convolution with this resolutionfunction is of interest. Here, we discuss basic concepts to efficient approaches for fits of QENS spectra basedon standard MATLAB and Python fit algorithms. We illustrate the fits with example data from IN16B, BASIS,and BATS.

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  • 35.
    Bengtsson, Torbjörn
    et al.
    Department of Medical Sciences, Örebro University, Örebro, Sweden.
    Lönn, Johanna
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces. PEAS Research Institute, Linköping, Sweden.
    Khalaf, Hazem
    Department of Medical Sciences, Örebro University, Örebro, Sweden.
    Palm, Eleonor
    Department of Medical Sciences, Örebro University, Örebro, Sweden.
    The lantibiotic gallidermin acts bactericidal against Staphylococcus epidermidis and Staphylococcus aureus and antagonizes the bacteria‐induced proinflammatory responses in dermal fibroblasts2018In: MicrobiologyOpen, E-ISSN 2045-8827, Vol. 7, no 6, article id e00606Article in journal (Refereed)
    Abstract [en]

    Antimicrobial resistance needs to be tackled from new angles, and antimicrobial peptides could be future candidates for combating bacterial infections. This study aims to investigate in vitro the bactericidal effects of the lantibiotic gallidermin on Staphylococcus epidermidis and Staphylococcus aureus, possible cytotoxic effects and its impact on host‐microbe interactions. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of gallidermin were determined, and cytotoxicity and proinflammatory effects of gallidermin on fibroblasts, red blood cells (RBCs) and in whole blood were investigated. Both MIC and MBC for all four tested strains of S. epidermidis was 6.25 μg/ml. Both MIC and MBC for methicillin‐sensitive S. aureus was 12.5 μg/ml and for methicillin‐resistant S. aureus (MRSA) 1.56 μg/ml. Gallidermin displayed no cytotoxic effects on fibroblasts, only a high dose of gallidermin induced low levels of CXCL8 and interleukin‐6. Gallidermin hemolyzed less than 1% of human RBCs, and did not induce reactive oxygen species production or cell aggregation in whole blood. In cell culture, gallidermin inhibited the cytotoxic effects of the bacteria and totally suppressed the bacteria‐induced release of CXCL8 and interleukin‐6 from fibroblasts. We demonstrate that gallidermin, expressing low cell cytotoxicity, is a promising candidate for treating bacterial infections caused by S. epidermidis and S. aureus, especially MRSA.

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  • 36.
    Bergdahl, Gizem Ertürk
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). CapSenze Biosystems AB, Lund, Sweden.
    Akhoundian, Maedeh
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Lueg-Althoff, Kyra
    Department of Chemistry, University of Duisburg-Essen, Universitätsstr. 7, Essen, 45117, Germany.
    Shinde, Sudhirkumar
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. School of Chemistry and Chemical Engineering, Queens University Belfast, Northern Ireland, United Kingdom.
    Yeung, Sing Yee
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Hedström, Martin
    CapSenze Biosystems AB, Lund, 223 63, Sweden; Department of Biotechnology, Lund University, Lund, 223 62, Sweden.
    Schrader, Thomas
    Department of Chemistry, University of Duisburg-Essen, Universitätsstr. 7, Essen, 45117, Germany.
    Mattiasson, Bo
    CapSenze Biosystems AB, Lund, 223 63, Sweden; Department of Biotechnology, Lund University, Lund, 223 62, Sweden.
    Sellergren, Börje
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Bisphosphonate Ligand Mediated Ultrasensitive Capacitive Protein Sensor: Complementary Match of Supramolecular and Dynamic Chemistry2019In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 43, no 2, p. 847-852Article in journal (Refereed)
    Abstract [en]

    Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for Trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the strong interaction of bisphosphonate with lysine/arginine residues on the surface of Trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.

  • 37.
    Beyer, Sarah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Kimani, Martha
    Chemical and Optical Sensing Division, Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Straße 11, 12489 Berlin, Germany.
    Zhang, Yuecheng
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Verhassel, Alejandra
    Institute of Biomedicine, University of Turku, 20520 Turku, Finland; FICAN West Cancer Centre, Turku University Hospital, 20520 Turku, Finland.
    Sternbæk, Louise
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Phase Holographic Imaging AB, SE-223 63 Lund, Sweden.
    Wang, Tianyan
    Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
    Persson, Jenny L.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
    Härkönen, Pirkko
    Institute of Biomedicine, University of Turku, 20520 Turku, Finland; FICAN West Cancer Centre, Turku University Hospital, 20520 Turku, Finland.
    Johansson, Emil
    Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden; Umeå Centre for Microbial Research, Umeå University, SE-901 87 Umeå, Sweden.
    Caraballo, Remi
    Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden; Umeå Centre for Microbial Research, Umeå University, SE-901 87 Umeå, Sweden.
    Elofsson, Mikael
    Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden; Umeå Centre for Microbial Research, Umeå University, SE-901 87 Umeå, Sweden.
    Gawlitza, Kornelia
    Chemical and Optical Sensing Division, Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Straße 11, 12489 Berlin, Germany.
    Rurack, Knut
    Chemical and Optical Sensing Division, Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Straße 11, 12489 Berlin, Germany.
    Ohlsson, Lars
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    El-Schich, Zahra
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gjörloff Wingren, Anette
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Stollenwerk, Maria M
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-Coated Polystyrene Cores-Assessment of the Binding Behavior to Cancer Cells.2022In: Cancers, ISSN 2072-6694, Vol. 14, no 8, article id 1875Article in journal (Refereed)
    Abstract [en]

    Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA. However, these protein molecules are usually expensive and easily denatured, which calls for the development of alternative glycan-specific receptors and cell imaging technologies. In this study, SA-imprinted fluorescent core-shell molecularly imprinted polymer particles (SA-MIPs) were employed to recognize SA on the cell surface of cancer cell lines. The SA-MIPs improved suspensibility and scattering properties compared with previously used core-shell SA-MIPs. Although SA-imprinting was performed using SA without preference for the α2,3- and α2,6-SA forms, we screened the cancer cell lines analyzed using the lectins Maackia Amurensis Lectin I (MAL I, α2,3-SA) and Sambucus Nigra Lectin (SNA, α2,6-SA). Our results show that the selected cancer cell lines in this study presented a varied binding behavior with the SA-MIPs. The binding pattern of the lectins was also demonstrated. Moreover, two different pentavalent SA conjugates were used to inhibit the binding of the SA-MIPs to breast, skin, and lung cancer cell lines, demonstrating the specificity of the SA-MIPs in both flow cytometry and confocal fluorescence microscopy. We concluded that the synthesized SA-MIPs might be a powerful future tool in the diagnostic analysis of various cancer cells.

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  • 38.
    Björklund, Sebastian
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Water vapor sorption-desorption hysteresis in glassy surface films of mucins investigated by humidity scanning QCM-D2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 545, p. 289-300Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Investigating the origin of water sorption-desorption hysteresis in glassy biopolymers is important for understanding the properties of biological barriers, such as the mucus epithelium. In general, hysteresis is a result of a complex interplay between diffusion of water and relaxation of the polymer matrix. Our hypothesis is that for thin films, typical for quartz crystal microbalance with dissipation monitoring (QCM-D) experiments performed in gas phase with defined relative humidity, the diffusion limitation is eliminated and hysteresis results only from relaxation of the polymer matrix. Experiments: We use a recently developed humidity scanning (HS) QCM-D method to obtain water sorption-desorption isotherms of mucin films under controlled conditions where water diffusion is not the limiting factor, neither in the vapor phase nor in the glassy mucin film. Findings: We present new results on the water sorption-desorption behavior of glassy mucin films with nanoscale thicknesses. Despite the fact that water diffusion is not the limiting factor, the sorption-desorption branches show clear hysteresis effects that are similar to those typically observed in bulk samples. The hydration-induced glass transition, resolved from monitoring the rheological behavior of the films, is shown to be in excellent agreement with the onset of the sorption-desorption hysteresis. We suggest that the hysteresis effect is related to a difference in dynamical and structural properties of the glassy materials depending on the hydration history of the films.

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  • 39.
    Bogdanova, Ekaterina
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. NextBioForm Competence Centre, Stockholm, Sweden.
    Fureby, Anna Millqvist
    RISE Research Institutes of Sweden, Stockholm, Sweden; NextBioForm Competence Centre, Stockholm, Sweden.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. NextBioForm Competence Centre, Stockholm, Sweden.
    Influence of cooling rate on ice crystallization and melting in sucrose-water system2022In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 111, no 7, p. 2030-2037, article id S0022-3549(22)00035-1Article in journal (Refereed)
    Abstract [en]

    The ice crystallization and melting in systems where the equilibrium state is difficult to reach is one of the growing areas in pharmaceutical freeze-drying research. The quality of the final freeze-dried product depends on the parameters of the cooling step, which affect the ice nucleation and growth. In this paper, we present a DSC study of ice crystallization and melting in a sucrose-water system. Using two different types of thermal cycles, we examine the influence of cooling and heating rates on the thermal behavior of sucrose-water solutions with water contents between 50 and 100 wt%.

    The DSC results show that low cooling rates provide crystallization at higher temperatures and lead to lower amount of nonfreezing water. Consequently, the glass transition and ice melting properties observed upon heating depend on the cooling conditions in the preceding step. Based on the experimental results, we investigate the reasons for the existence of the two steps on DSC heating curves in sucrose-water systems: the glass transition step and the onset of ice melting. We show that diffusion of water can be the limiting factor for ice growth and melting in the sucrose-water system when the amorphous phase is in a liquid state. In particular, when the diffusion coefficient drops below 10−14 m2/sec, the ice crystals growth or melting becomes strongly suppressed even above the glass transition temperature. Understanding the diffusion limitations in the sucrose-water system can be used for the optimization of the freeze-drying protocols for proteins and probiotics.

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  • 40.
    Bogdanova, Ekaterina
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Assessment of activation energy of enthalpy relaxation in sucrose-water system: effects of DSC cycle type and sample thermal history2022In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 147, p. 9695-9709Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to critically analyze different methods of calculation of activation energy of relaxation in sucrose-water system from differential scanning calorimetry data. We consider the use of different thermal cycles for calculations together with Moynihan and Kissinger equations. We study the effect of two methods of glass transition temperature determination (half-step and inflection point) on the activation energy values. Along with experimental DSC data, we use the data simulated using Tool-Narayanaswamy-Moynihan model to validate the use of cooling and heating curves and to check the reproducibility of the activation energy calculations. The obtained results show that the thermal cycle with equal cooling and heating rates provides the most reliable data set and the glass transition temperature definition using inflection point rather than half step can be recommended for calculations. Moreover, due to technical reasons, heating rather than cooling scans provide the most reliable results of activation energy calculations. Furthermore, a simple method based on the width of the glass transition region shows reasonable results for single scan experiments. The activation energies of the glass transition in sucrose-water system with different water contents and different thermal histories were studied. Since it is impossible to apply traditional methods based on Moynihan equation for the activation energy evaluation for freeze-dried samples, we propose using another method based on the properties of the recovery peak. Combining the results obtained by different methods, we present a dependence of activation energy in sucrose-water system on water content. The results show that water decreases the activation energy of relaxation process in sucrose matrix.

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  • 41.
    Bogdanova, Ekaterina
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lages, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. MAX IV Laboratory, Lund University, Lund SE-22484, Sweden.
    Phan-Xuan, Tuan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. MAX IV Laboratory, Lund University, Lund SE-22484, Sweden.
    Kamal, Md Arif
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden.
    Terry, Ann
    MAX IV Laboratory, Lund University, Lund SE-22484, Sweden.
    Millqvist Fureby, Anna
    RISE Research Institutes of Sweden, Stockholm SE-114 86, Sweden.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lysozyme-Sucrose Interactions in the Solid State: Glass Transition, Denaturation, and the Effect of Residual Water.2023In: Molecular Pharmaceutics, ISSN 1543-8384, E-ISSN 1543-8392, Vol. 20, no 9, p. 4664-4675Article in journal (Refereed)
    Abstract [en]

    The freeze-drying of proteins, along with excipients, offers a solution for increasing the shelf-life of protein pharmaceuticals. Using differential scanning calorimetry, thermogravimetric analysis, sorption calorimetry, and synchrotron small-angle X-ray scattering (SAXS), we have characterized the properties at low (re)hydration levels of the protein lysozyme, which was freeze-dried together with the excipient sucrose. We observe that the residual moisture content in these samples increases with the addition of lysozyme. This results from an increase in equilibrium water content with lysozyme concentration at constant water activity. Furthermore, we also observed an increase in the glass transition temperature (Tg) of the mixtures with increasing lysozyme concentration. Analysis of the heat capacity step of the mixtures indicates that lysozyme does not participate in the glass transition of the sucrose matrix; as a result, the observed increase in the Tg of the mixtures is the consequence of the confinement of the amorphous sucrose domains in the interstitial space between the lysozyme molecules. Sorption calorimetry experiments demonstrate that the hydration behavior of this formulation is similar to that of the pure amorphous sucrose, while the presence of lysozyme only shifts the sucrose transitions. SAXS analysis of amorphous lysozyme–sucrose mixtures and unfolding of lysozyme in this environment show that prior to unfolding, the size and shape of lysozyme in a solid sucrose matrix are consistent with its native state in an aqueous solution. The results obtained from our study will provide a better understanding of the low hydration behavior of protein–excipient mixtures and support the improved formulation of biologics.

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  • 42.
    Bogdanova, Ekaterina
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Millqvist Fureby, Anna
    RISE Research Institutes of Sweden.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Hydration enthalpies of amorphous sucrose, trehalose and maltodextrins and their relationship with heat capacities2021In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, no 26, p. 14433-14448Article in journal (Refereed)
    Abstract [en]

    The mechanisms of glass transitions and the behavior of small solute molecules in a glassy matrix are some of the most important topics of modern thermodynamics. Water plays an important role in the physical and chemical stability of lyophilized biologics formulations, in which glassy carbohydrates act as cryoprotectants and stabilizers. In this study, sorption calorimetry was used for simultaneous measurements of water activity and the enthalpy of water sorption by amorphous sucrose, trehalose and maltodextrins. Moreover, the heat capacity of these carbohydrates in mixtures with water was measured by DSC in a broad range of water contents. The hydration enthalpies of glassy sucrose, trehalose and maltodextrins are exothermic, and the enthalpy change of water-induced isothermal glass transitions is higher for small molecules. The partial molar enthalpy of mixing of water in slow experiments is about -18 kJ mol-1, but less exothermic in the case of small molecules at fast hydration scan rates. By measuring the heat capacities of disaccharides and maltodextrins as a function of water content, we separated the contributions of carbohydrates and water to the total heat capacities of the mixtures. The combination of these data allowed testing of thermodynamic models describing the hydration-induced glass transitions. The heat capacity changes calculated by the fitting of the hydration enthalpy data for disaccharides are in good agreement with the heat capacity data obtained by DSC, while for maltodextrins, the effect of sub-Tg transitions should be taken into account. Combining the data obtained by different techniques, we found a distinct difference in the behavior of water in glassy polymers compared to that in glassy disaccharides. By understanding the behavior of water in glassy carbohydrates, these results can be used to improve the design of freeze-dried formulations of proteins and probiotics.

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  • 43.
    Boisen, Gabriella
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Davies, Julia R
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Acid tolerance in early colonizers of oral biofilms2021In: BMC Microbiology, E-ISSN 1471-2180, Vol. 21, no 1, article id 45Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A. naeslundii and A. odontolyticus) and examined the role of salivary proteins in acid tolerance development.

    METHODS: Biofilms were formed on surfaces in Ibidi® mini flow cells with or without a coating of salivary proteins and acid tolerance assessed by exposing them to a challenge known to kill non-acid tolerant cells (pH 3.5 for 30 min) followed by staining with LIVE/DEAD BacLight and confocal scanning laser microscopy. The ability to induce an ATR was assessed by exposing the biofilms to an adaptation pH (pH 5.5) for 2 hours prior to the low pH challenge.

    RESULTS: Biofilm formation significantly increased acid tolerance in all the clinical streptococcal strains (P < 0.05) whereas the laboratory strains varied in their response. In biofilms, S. oralis was much more acid tolerant than S. gordonii or S. mutans. A. naeslundii showed a significant increase in acid tolerance in biofilms compared to planktonic cells (P < 0.001) which was not seen for A. odontolyticus. All strains except S. oralis induced an ATR after pre-exposure to pH 5.5 (P < 0.05). The presence of a salivary pellicle enhanced both acid tolerance development and ATR induction in S. gordonii biofilms (P < 0.05) but did not affect the other bacteria to the same extent.

    CONCLUSIONS: These findings suggest that factors such as surface contact, the presence of a salivary pellicle and sensing of environmental pH can contribute to the development of high levels of acid tolerance amongst early colonizers in oral biofilms which may be important in the initiation of caries.

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  • 44.
    Boisen, Gabriella
    et al.
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Prgomet, Zdenka
    Malmö University, Faculty of Odontology (OD). Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Enggren, Gabriela
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Dahl, Hanna
    Malmö University, Faculty of Odontology (OD).
    Mkadmi, Cindy
    Malmö University, Faculty of Odontology (OD).
    Davies, Julia R
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Limosilactobacillus reuteri inhibits the acid tolerance response in oral bacteria2023In: Biofilm, E-ISSN 2590-2075, Vol. 6, article id 100136Article in journal (Refereed)
    Abstract [en]

    Probiotic bacteria show promising results in prevention of the biofilm-mediated disease caries, but the mechanisms are not fully understood. The acid tolerance response (ATR) allows biofilm bacteria to survive and metabolize at low pH resulting from microbial carbohydrate fermentation. We have studied the effect of probiotic strains: Limosilactobacillus reuteri and Lacticaseibacillus rhamnosus on ATR induction in common oral bacteria. Communities of L. reuteri ATCC PTA5289 and Streptoccus gordonii, Streptococcus oralis, Streptococcus mutans or Actinomyces naeslundii in the initial stages of biofilm formation were exposed to pH 5.5 to allow ATR induction, followed by a low pH challenge. Acid tolerance was evaluated as viable cells after staining with LIVE/ DEAD & REG;BacLightTM. The presence of L. reuteri ATCC PTA5289 caused a significant reduction in acid tolerance in all strains except S. oralis. When S. mutans was used as a model organism to study the effects of additional probiotic strains (L. reuteri SD2112, L. reuteri DSM17938 or L. rhamnosus GG) as well as L. reuteri ATCC PTA5289 supernatant on ATR development, neither the other probiotic strains nor supernatants showed any effect. The presence of L. reuteri ATCC PTA5289 during ATR induction led to down-regulation of three key genes involved in tolerance of acid stress (luxS, brpA and ldh) in Streptococci. These data suggest that live cells of probiotic L. reuteri ATCC PTA5289 can interfere with ATR development in common oral bacteria and specific strains of L. reuteri may thus have a role in caries prevention by inhibiting development of an acid-tolerant biofilm microbiota.

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  • 45.
    Boyd, Hannah
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    On the structure and mechanical properties of in vitro salivary pellicles2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Salivary pellicles display exceptional hydration and lubrication performance. At present, there are still gaps in the understanding of how this is achieved. The aim of this thesis was therefore to increase our knowledge on the mechanisms underlying these properties and deepen the understanding of how they are related to the composition and structure of pellicles, with a focus on those formed under in vitro conditions. This has applications ranging from the development of artificial saliva and lubricating coatings for biomedical applications to methodological approaches for initial testing of oral healthcare products. For this, we also focused on developing suitable methodological approaches for these studies, centering on atomic force microscopy, quartz crystal microbalance with dissipation monitoring, ellipsometry and neutron reflectometry techniques, to investigate in vitro and model salivary pellicles.

    First, we confirmed a two-layer structure for in vitro salivary pellicles and showed that the outer layer is mainly composed by the oral mucin MUC5B, but that it also contains other salivary components that enhance swelling and hydration. In the presence of bulk saliva, the outer layer also contains a reversibly and loosely bound fraction. This fraction increases the adhesiveness of the pellicle but unexpectedly has no significant effect on its lubrication performance. We also investigated the effect of mechanical confinement on model salivary pellicles by means of Neutron Reflectometry, revealing that at a pressure of 1 bar they are already completely compressed and dehydrated. Finally, with the aim to advance towards better oral healthcare products, we investigated the effect of nonionic and amphoteric surfactants on salivary pellicles, showing that they have a gentler effect on pellicle structure than the commonly employed anionic surfactants.

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  • 46.
    Boyd, Hannah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gonzalez-Martinez, J.F.
    Arnebrant, T.
    Sotres, J.
    Role of the reversibly bound fraction of in vitro salivary pellicles on their mechanical and lubrication propertiesManuscript (preprint) (Other academic)
  • 47.
    Boyd, Hannah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gonzalez-Martinez, Juan F
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Welbourn, Rebecca J L
    ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK.
    Gutfreund, Philipp
    Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France.
    Klechikov, Alexey
    Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden.
    Robertsson, Carolina
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Wickström, Claes
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Arnebrant, Thomas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Barker, Robert
    School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, UK.
    Sotres, Javier
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    A comparison between the structures of reconstituted salivary pellicles and oral mucin (MUC5B) films.2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 584, p. 660-668, article id S0021-9797(20)31464-8Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure.

    EXPERIMENTS: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry.

    FINDINGS: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.

  • 48.
    Boyd, Hannah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gonzalez-Martinez, Juan F
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Welbourn, Rebecca J L
    Rutherford Appleton Laboratory, UK.
    Ma, Kun
    Rutherford Appleton Laboratory, UK.
    Li, Peixun
    Rutherford Appleton Laboratory, UK.
    Gutfreund, Philipp
    Institut Laue Langevin, France.
    Klechikov, Alexey
    Institut Laue Langevin, France; Uppsala University.
    Arnebrant, Thomas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Barker, Robert
    University of Kent, UK.
    Sotres, Javier
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Effect of nonionic and amphoteric surfactants on salivary pellicles reconstituted in vitro2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 12913Article in journal (Refereed)
    Abstract [en]

    Surfactants are important components of oral care products. Sodium dodecyl sulfate (SDS) is the most common because of its foaming properties, taste and low cost. However, the use of ionic surfactants, especially SDS, is related to several oral mucosa conditions. Thus, there is a high interest in using non-ionic and amphoteric surfactants as they are less irritant. To better understand the performance of these surfactants in oral care products, we investigated their interaction with salivary pellicles i.e., the proteinaceous films that cover surfaces exposed to saliva. Specifically, we focused on pentaethylene glycol monododecyl ether (C12E5) and cocamidopropyl betaine (CAPB) as model nonionic and amphoteric surfactants respectively, and investigated their interaction with reconstituted salivary pellicles with various surface techniques: Quartz Crystal Microbalance with Dissipation, Ellipsometry, Force Spectroscopy and Neutron Reflectometry. Both C12E5 and CAPB were gentler on pellicles than SDS, removing a lower amount. However, their interaction with pellicles differed. Our work indicates that CAPB would mainly interact with the mucin components of pellicles, leading to collapse and dehydration. In contrast, exposure to C12E5 had a minimal effect on the pellicles, mainly resulting in the replacement/solubilisation of some of the components anchoring pellicles to their substrate.

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  • 49.
    Buchanan, Claire
    et al.
    Department of Chemistry and Physics, La Trobe University, Bundoora, Australia.
    Garvey, Christopher J.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Australian Nuclear Science and Technology Organization (ANSTO), Lucas Heights, Australia; Lund Institute for Advanced Neutron and X-ray Science (LINXS), Lund, Sweden.
    Puskar, Ljiljana
    Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    Perlmutter, Patrick
    Department of Chemistry and Physics, La Trobe University, Bundoora, Australia.
    Mechler, Adam
    Department of Chemistry and Physics, La Trobe University, Bundoora, Australia.
    Coordination crosslinking of helical substituted oligoamide nanorods with Cu(II)2020In: Supramolecular chemistry (Print), ISSN 1061-0278, E-ISSN 1029-0478, Vol. 32, no 3, p. 222-232Article in journal (Refereed)
    Abstract [en]

    Substituted oligoamides are short sequences of unnatural amino acids. Oligoamides made entirely of beta(3) amino acids yield helical monomers that, if N-acylated, assemble into nanorod structures via a supramolecular assembly motif. In this work, coordination crosslinking was used to create complex nanomaterials from oligoamides WKLWEL (KE) and WELWEL (EE) (the letters denote the analogous alpha-amino acids). Upon Cu(II) addition, atomic force microscopy and small angle neutron scattering revealed morphologic changes specific to KE but absent in EE. Vibration spectroscopy measurements revealed that Cu(II) can coordinate to the amine moieties of the side chains, without direct effect on the backbone amides. While coordination in excess solvent lead to regular nanostructures, fast drying of the sample yielded oligoamide templated crystallization of CuCl2. The metal coordination crosslinking of supramolecular assemblies as reported here is the first realization of a metallosupramolecular framework structure. [GRAPHICS] .

  • 50.
    Buchanan, Claire
    et al.
    La Trobe Univ, Dept Chem & Phys, Bundoora, Vic, Australia..
    Hinds, Mark G.
    Univ Melbourne, Bio21 Mol Sci & Biotechnol Inst, Parkville, Vic, Australia..
    Puskar, Ljiljana
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Berlin, Germany..
    Garvey, Christopher J.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Lund Inst Adv Neutron & Xray Sci, S-22370 Lund, Sweden..
    Mechler, Adam
    La Trobe Univ, Dept Chem & Phys, Bundoora, Vic, Australia..
    Comprehensive multidimensional study of the self-assembly properties of a three residue substituted beta(3) oligoamide2021In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 93, no 11, p. 1327-1341Article in journal (Refereed)
    Abstract [en]

    Substituted (beta(3) oligoamides form a unique self-assembling system where each monomer folds into a helix containing approximately three (beta(3) amino acids per turn, yielding a geometrically well-defined cylindrical building block that, when N-acylated, is able to self-assemble head-to-tail into nanorods that can reach several 100 mu m length. It was shown in previous works that self-assembly can be achieved with a three residue long oligoamide as well that lacks any intramolecular H-bonds, yet it crystallizes in a helix-like conformation. The self-assembly properties of these small oligoamides are however elusive, suggesting a more complex system than the self-assembly of the H-bond stabilized helical monomers. Here we focus on the self-assembly behaviour of a three residue oligoamide, Ac-beta(3)[LIA] where the letters denote the side chain of the analogous a amino acid. Ac-beta(3)[LIA] can yield highly inhomogeneous suspensions in water with a broad range of large fibrous structures that seem to be very stable, yet occasionally fibre growth is only observed upon heating. The small size of the monomer suggests a highly dynamic equilibrium yet all previous attempts failed to clearly identify low molecular weight species. Therefore a special methodology was employed in this study to characterize the suspensions at different size ranges: SANS that is optimal to measure the small oligomers and cross sectional diameter of the assemblies, DLS that is sensitive to the large populations and therefore the length of the superstructures, and NMR that is sensitive to monomeric and small oligomeric form, in conjunction with IR spectroscopy to probe the folding and AFM to image the morphology of the assemblies. Temperature ramping was used to perturb the system to probe the dynamicity of the self-assembly. It was found that the anomalous self-assembly behaviour of Ac-beta(3)[LIA] is caused by its two stable conformations, a helix-building "horseshoe" fold and a linear conformer. The latter is exclusively found in monomeric form in solution whereas the horseshoe fold is stable in solid phase and in fibrous assemblies. Small oligomers were absent. Thus the self assembly of Ac-beta(3)[LIA] is arrested by the activation energy need of the conformation change; fibre growth might be triggered by conditions that allow increased conformational freedom of the monomers. This observation may be used to develop strategies for controlled switchable self-assembly.

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