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  • 1. Andoralov, Viktor
    et al.
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Flexible micro(bio)sensors for quantitative analysis of bioanalytes in a nanovolume of human lachrymal liquid2013In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 405, no 11, p. 3871-3879Article in journal (Refereed)
    Abstract [en]

    A flexible electrochemical micro(bio)sensor has been designed for determination of several biological compounds, specifically, ascorbate, dopamine, and glucose, in human lachrymal liquid (tears). The microsensor for simultaneous determination of ascorbate and dopamine concentrations was based on a gold microwire modified with the tetrathiafulvalen–7,7,8,8-tetracyanoquinodimethane complex as a catalyst. To monitor glucose concentration in tears, glucose dehydrogenase was immobilized on a gold microwire modified with carbon nanotubes and an osmium redox polymer. A capillary microcell was constructed for sampling tears. The cell had a working volume of 60–100 nL with a sampling deviation of 6.7 %. To check if the microcell was properly filled with buffer or tear sample, a control electrode was introduced into the construction. The electrode was used to measure the electrical resistance of a fully filled nanovolume cell. The mechanical flexibility is one of the most important features of the prototype and allowed direct collection of tears with minimized risk of damage to the eye.

  • 2.
    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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  • 3.
    Björklund, Sebastian
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Quoc Dat, Pham
    Bastholm Jensen, Louise
    Østergaard Knudsen, Nina
    Dencker Nielsen, Lars
    Ekelund, Katarina
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Sparr, Emma
    The effects of polar excipients transcutol and dexpanthenol on molecular mobility, permeability, and electrical impedance of the skin barrier2016In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 479, p. 207-220Article in journal (Refereed)
    Abstract [en]

    In the development of transdermal and topical products it is important to understand how formulation ingredients interact with the molecular components of the upper layer of the skin, the stratum corneum (SC), and thereby influence its macroscopic barrier properties. The aim here was to investigate the effect of two commonly used excipients, transcutol and dexpanthenol, on the molecular as well as the macroscopic properties of the skin membrane. Polarization transfer solid-state NMR methods were combined with steady-state flux and impedance spectroscopy measurements to investigate how these common excipients influence the molecular components of SC and its barrier function at strictly controlled hydration conditions in vitro with excised porcine skin. The NMR results provide completely new molecular insight into how transcutol and dexpanthenol affect specific molecular segments of both SC lipids and proteins. The presence of transcutol or dexpanthenol in the formulation at fixed water activity results in increased effective skin permeability of the model drug metronidazole. Finally, impedance spectroscopy data show clear changes of the effective skin capacitance after treatment with transcutol or dexpanthenol. Based on the complementary data, we are able to draw direct links between effects on the molecular properties and on the macroscopic barrier function of the skin barrier under treatment with formulations containing transcutol or dexpanthenol.

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  • 4.
    Björklund, Sebastian
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Nowacka, Agnieszka
    Dahi, Ihab
    Topgaard, Daniel
    Spaar, Emma
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Skin membrane electrical impedance properties under the influence of a varying water gradient2013In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 104, no 12, p. 2639-2650Article in journal (Refereed)
    Abstract [en]

    The stratum corneum (SC) is an effective permeability barrier. One strategy to increase drug delivery across skin is to increase the hydration. A detailed description of how hydration affects skin permeability requires characterization of both macroscopic and molecular properties and how they respond to hydration. We explore this issue by performing impedance experiments on excised skin membranes in the frequency range 1 Hz to 0.2 MHz under the influence of a varying gradient in water activity (aw). Hydration/dehydration induces reversible changes of membrane resistance and effective capacitance. On average, the membrane resistance is 14 times lower and the effective capacitance is 1.5 times higher when the outermost SC membrane is exposed to hydrating conditions (aw ¼ 0.992), as compared to the case of more dehydrating conditions (aw ¼ 0.826). Molecular insight into the hydration effects on the SC components is provided by natural-abundance 13C polarization transfer solidstate NMR and x-ray diffraction under similar hydration conditions. Hydration has a significant effect on the dynamics of the keratin filament terminals and increases the interchain spacing of the filaments. The SC lipids are organized into lamellar structures with ~ 12.6 nm spacing and hexagonal hydrocarbon chain packing with mainly all-trans configuration of the acyl chains, irrespective of hydration state. Subtle changes in the dynamics of the lipids due to mobilization and incorporation of cholesterol and long-chain lipid species into the fluid lipid fraction is suggested to occur upon hydration, which can explain the changes of the impedance response. The results presented here provide information that is useful in explaining the effect of hydration on skin permeability.

  • 5.
    Cao, Zhen
    et al.
    Lund Univ, Dept Energy Sci, Lund, Sweden..
    Pham, Anh Duc
    Lund Univ, Dept Energy Sci, Lund, Sweden..
    Wu, Zan
    Lund Univ, Dept Energy Sci, Lund, Sweden..
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Albèr, Cathrine
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sunden, Bengt
    Lund Univ, Dept Energy Sci, Lund, Sweden..
    Pool boiling heat transfer enhancement of water by gold nanoparticles with an electrophoretic deposition method2019In: Proceedings of the Asme International Mechanical Engineering Congress and Exposition, 2018, vol 8b, Amer Soc Mechanical Engineers , 2019Conference paper (Other academic)
    Abstract [en]

    Saturated pool boiling heat transfer of water is investigated experimentally on copper surfaces with nanoparticle coatings at atmospheric pressure. The coatings are generated by an electrophoretic deposition method (EPD). Three modified surfaces are prepared with gold nanoparticles of 0.20 mg, 0.25 mg and 0.30 mg, respectively. During the deposition, ethanol works as the solvent while the electrical potential and deposition time are controlled as 9.5 V and 30 min, respectively. The experimental results show that heat transfer coefficients (HTC) and critical heat fluxes (CHF) are enhanced on the modified surfaces. HTC increases with decreasing thickness of the coating, while CHF increases with increasing thickness of the coating. CHFs of EPD-0.20 mg, EPD-0.25 mg and EPD-0.30 mg are 93 W/cm2, 123 W/cm2 and 142 W/cm2, respectively, which are increased by 7%, 41% and 63% compared with the smooth surface. EPD-0.20 mg performs the best on heat transfer, with a maximum enhancement of around 60%. At the end, a brief review about mechanistic models of heat transfer at low and moderate heat fluxes is provided, based on which, the reasons why heat transfer is enhanced are discussed.

  • 6. Cao, Zhen
    et al.
    Wu, Zan
    Department of Energy Sciences, Lund University, P.O. Box 118, Lund, SE-22100, Sweden.
    Pham, Anh Duc
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Department of Energy Sciences, Lund University, P.O. Box 118, Lund, SE-22100, Sweden.
    Preger, Calle
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Albèr, Cathrine
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Abbood, Sahar A.
    Department of Energy Sciences, Lund University, P.O. Box 118, Lund, SE-22100, Sweden.
    Sunden, Bengt
    Enhancement of HFE-7200 pool boiling heat transfer on copper surfaces with nanoparticle coatings2018In: International Heat Transfer Conference 16, Begell House, 2018, p. -1347Conference paper (Refereed)
    Abstract [en]

    Saturated pool boiling heat transfer of HFE-7200 is investigated experimentally on copper surfaces with nanoparticle coatings at atmospheric pressure. The coatings are generated by an electrophoretic deposition method. Two modified surfaces are prepared with Cu-Zinc nanoparticles of 0.3 mg and 0.6 mg, respectively. During the deposition, ethanol works as the solvent while the electrical potential and deposition time are controlled as 9.5 V and 30 min, respectively. The experimental results show heat transfer is considerably enhanced by the nanoparticle coatings. The surface with 0.6 mg nanoparticles (EDS-2) performs better than the surface with 0.3 mg nanoparticles (EDS-1), and a maximum 140% heat transfer enhancement is achieved on the surface EDS-2 compared with the SS. However, the critical heat flux is not enhanced by the coatings but even slightly decreased. A high speed visualization is employed to capture bubble behavior. It is found that bubbles on EDS-1 and EDS-2 have smaller sizes and higher departure frequency than those on the SS before reaching the critical heat flux. However, at critical heat fluxes, a vapor blanket appears on all surfaces.

  • 7. Cao, Zhen
    et al.
    Zan, Wu
    Pham, Anh-Duc
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Department of Energy Sciences, Lund University, Box 118, SE-22100 Lund, Sweden.
    Yang, Yanjie
    Abbood, Sahar
    Falkman, Peter
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Albèr, Cathrine
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sundén, Bengt
    Pool boiling of HFE-7200 on nanoparticle-coating surfaces: Experiments and heat transfer analysis2019In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 133, p. 548-560Article in journal (Refereed)
    Abstract [en]

    In the present study, an electrophoretic deposition method was employed to modify copper surfaces with Cu-Zn (∼100 nm) nanoparticles. Pool boiling heat transfer of HFE-7200 on the modified surfaces was experimentally studied. The results showed that the heat transfer coefficient on the modified surfaces was significantly enhanced compared with that on a smooth surface, e.g., a maximum 100% enhancement, while the maximum superheat on the modified surfaces was around 20 K lower than that on the smooth surface. However, the critical heat flux (CHF) was not improved considerably, and supplementary tests indicated that the wickability of HFE-7200 was almost the same on the modified surfaces and the smooth surface. The departure diameters of bubbles were recorded by a high speed camera, which were compared with several models in literature. Active nucleation site sizes were evaluated by the Hsu nucleation theory and active nucleation site densities were estimated by appropriate correlations. In addition, a heat transfer model, considering natural convection, re-formation of thermal boundary layer and microlayer evaporation, was formulated to predict the heat transfer on the modified surfaces and the smooth surface. A relatively good prediction was achieved.

  • 8. Coman, Vasile
    et al.
    Ludwig, Roland
    Harreither, Wolfgang
    Haltrich, Dietmar
    Gorton, Lo
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS).
    A direct electron transfer-based glucose/oxygen biofuel cell operating in human serum2010In: Fuel Cells, ISSN 1615-6846, E-ISSN 1615-6854, Vol. 10, no 1, p. 9-16Article in journal (Refereed)
    Abstract [en]

    We report on the fabrication and characterisation of the very first direct electron transfer-based glucose/oxygen biofuel cell (BFC) operating in neutral glucose-containing buffer and human serum. Corynascus thermophilus cellobiose ehydrogenase and Myrothecium verrucaria bilirubin oxidase were used as anodic and cathodic bioelements, respectively. The following characteristics of the mediator-, separator- and membrane-less, a priori, non-toxic and simple miniature BFC, was obtained: an open-circuit voltage of 0.62 and 0.58 V, a maximum power density of ca. 3 and 4 lW cm–2 at 0.37 and 0.19 V of cell voltage, in phosphate buffer and human serum, respectively.

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  • 9. Coman, Vasile
    et al.
    Vaz-Dominguez, Cristina
    Ludwig, Roland
    Harreither, Wolfgang
    Haltrich, Dietmar
    De Lacey, Antonio L.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Gorton, Lo
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS).
    A membrane-, mediator-, cofactor-less glucose/oxygen biofuel cell2008In: Physical Chemistry Chemical Physics, Vol. 10, no 40, p. 6093-6096Article in journal (Refereed)
  • 10. Czolkos, Ilja
    et al.
    Dock, Eva
    Tonning, Erik
    Christensen, Jakob
    Winther-Nielsen, Margrethe
    Carlsson, Charlotte
    Mojzikova, Renata
    Skladal, Petr
    Wollenberger, Ulla
    Norgaard, Lars
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Emneus, Jenny
    Prediction of wastewater quality using amperometric bioelectronic tongues2016In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 75, p. 375-382Article in journal (Refereed)
    Abstract [en]

    Wastewater samples from a Swedish chemi-thermo-mechanical pulp (CTMP) mill collected at different purification stages in a wastewater treatment plant (WWTP) were analyzed with an amperometric enzyme-based biosensor array in a flow-injection system. In order to resolve the complex composition of the wastewater, the array consists of several sensing elements which yield a multidimensional response. We used principal component analysis (PCA) to decompose the array's responses, and found that wastewater with different degrees of pollution can be differentiated. With the help of partial least squares regression (PLS-R), we could link the sensor responses to the Microtox (R) toxicity parameter, as well as to global organic pollution parameters (COD, BOD, and TOC). From investigating the influences of individual sensors in the array, it was found that the best models were in most cases obtained when all sensors in the array were included in the PLS-R model. We find that fast simultaneous determination of several global environmental parameters characterizing wastewaters is possible with this kind of biosensor array, in particular because of the link between the sensor responses and the biological effect onto the ecosystem into which the wastewater would be released. In conjunction with multivariate data analysis tools, there is strong potential to reduce the total time until a result is yielded from days to a few minutes. (C) 2015 Elsevier B.V. All rights reserved.

  • 11. Dagys, Marius
    et al.
    Haberska, Karolina
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Kulys, Juozas
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Laccase-gold nanoparticle assisted bioelectrocatalytic reduction of oxygen2010In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 12, no 7, p. 933-935Article in journal (Refereed)
    Abstract [en]

    It was found that homogeneous activity of Trametes hirsuta laccase is considerably diminished in the presence of gold nanoparticles (Au-NPs). Heterogeneous electron transfer studies revealed that Au-NPs facilitate direct electron transfer (DET) between the T1 copper site of the laccase and the surface of Au-NP modified electrodes. DET was characterized by the standard heterogeneous ET constant of 0.5 +/- 0.6 s(-1) at Au-NPs with an average diameter of 50 nm. As a consequence of this a well pronounced DET based bioelectrocatalytic oxygen reduction with current densities of 5-30 mu A cm(-2) has been achieved at the laccase-Au-NP modified electrodes.

  • 12. Dagys, Marius
    et al.
    Lamberg, Peter
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Niaura, Gediminias
    Bachmatova, Irina
    Marcinkeviciene, Lucija
    Meskys, Rolandas
    Kulys, Juozas
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Comparison of bioelectrocatalysis at Trichaptum abietinum and Trametes hirsuta laccase modified electrodes2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 130, p. 141-147Article in journal (Refereed)
    Abstract [en]

    Bioelectrocatalytic reduction of oxygen to water at electrodes modified with gold nanoparticles and a new laccase from Trichaptum abietinum (TaLc) was studied. The bioelectrocatalytic current was found to be much higher at TaLc modified electrodes than at similarly prepared electrodes modified with a broadly used laccase from Trametes hirsuta (ThLc). To explain this difference the bioelectrocatalysis was described in terms of kinetic rate constants based on simultaneous cyclic voltammetry and quartz crystal microbalance measurements. From analysis of the rate constants both laccases appeared to possess similar rates (k(0)) of direct electron transfer. However, the enzyme turnover (k(cat)) was about three-fold higher for gold nanoparticle bound TaLc than for ThLc, calculated using surface concentration of enzyme established by QCM-D. Near reversible potential-induced reorientation of adsorbed proteins was observed by surface enhanced Raman spectroscopy. (C) 2014 Elsevier Ltd. All rights reserved.

  • 13.
    Ding, R.
    et al.
    Nanyang Technological University, Singapore.
    Joon, N. K.
    Åbo Akademi University, Finland.
    Ahamed, A.
    Åbo Akademi University, Finland; Nanyang Environment and Water Research Institute, Singapore.
    Shafaat, Atefeh
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Guzinski, M.
    Vanderbilt University Medical Center, Nashville, USA.
    Wagner, M.
    Nanyang Environment and Water Research Institute, Singapore.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Bobacka, J.
    Åbo Akademi University, Finland.
    Lisak, G.
    Nanyang Technological University, Singapore; Nanyang Environment and Water Research Institute, Singapore.
    Gold-modified paper as microfluidic substrates with reduced biofouling in potentiometric ion sensing2021In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 344, article id 130200Article in journal (Refereed)
    Abstract [en]

    Microfluidic sampling media based on paper and its modifications with either gold nanoparticles or sputtered gold were evaluated for potentiometric determination of Na+, K+, and Cl– ions in clinically relevant samples. The measurements were conducted in comparison to other commonly considered microfluidic substrates, i.e. sponge, polyester textile, and polyamide textile. Ion determination was done by using solid-contact ion-selective electrodes based on plasticized PVC membranes for Na+, K+, and Cl– ions and utilizing PEDOT(PSS) or PEDOT(Cl) as the ion-to-electron transducer. The solid-contact ion-selective electrodes and a solid-state reference electrode were placed directly on the substrate into which the sample solution was wicked. Transport of bovine serum albumin (BSA) through the paper substrate was studied by ellipsometry. Modification of the paper substrates by gold nanoparticles (AuNPs) was found to slow down the transport of BSA through the paper, when compared with unmodified paper substrates and when compared with all the other alternative sampling matrices studied. The retention of BSA obtained with AuNP-modified paper substrates significantly improved the accuracy of the potentiometric ion determinations in sweat, saliva, artificial tears, and artificial serum. The potentiometric results were validated by inductively coupled plasma optical emission spectrometry (ICP-OES) and ion chromatography (IC). The study indicates that modification of paper by AuNPs is a feasible approach to reduce biofouling of sensors that are used in the paper-based analysis of clinically relevant samples. © 2021 Elsevier B.V.

  • 14. Erturk, Gizem
    et al.
    Hedstrom, Martin
    Mattiasson, Bo
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Lood, Rolf
    Highly sensitive detection and quantification of the secreted bacterial benevolence factor RoxP using a capacitive biosensor: A possible early detection system for oxidative skin diseases2018In: PLOS ONE, E-ISSN 1932-6203, Vol. 13, no 3Article in journal (Refereed)
    Abstract [en]

    The impact of the microbiota on our health is rapidly gaining interest. While several bacteria have been associated with disease, and others being indicated as having a probiotic effect, the individual biomolecules behind these alterations are often not known. A major problem in the study of these factors in vivo is their low abundance in complex environments. We recently identified the first secreted bacterial antioxidant protein, RoxP, from the skin commensal Propionibacterium acnes, suggesting its relevance for maintaining the redox homeostasis on the skin. In order to study the effect, and prevalence, of RoxP in vivo, a capacitive biosensor with a recognition surface based on molecular imprinting was used to detect RoxP on skin in vivo. In vitro analyses demonstrated the ability to detect and quantify RoxP in a concentration range of 1 x 10(-13) M to 1 x 10(-8) M from human skin swabs; with a limit of detection of 2.5 x 10(-19) M in buffer systems. Further, the biosensor was highly selective, not responding to any other secreted protein from P. acnes. Thus, it was possible to demonstrate the presence, and quantity, of RoxP on human skin. Therefore, the developed biosensor is a very promising tool for the detection of RoxP from clinical samples, offering a rapid, cost-effective and sensitive means of detecting low-abundant bacterial proteins in vivo in complex milieus.

  • 15.
    Eskandari, Mahboubeh
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Center of Excellence in Electrochemistry, School of Chemistry, University of Tehran, Tehran, Iran; Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
    Rembiesa, Jadwiga
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. In vitro Plant-tech AB, 216 18, Limhamn, Sweden.
    Startaite, Lauryna
    Holefors, Anna
    Valanciute, Audrone
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Faridbod, Farnoush
    Ganjali, Mohammad Reza
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Polyphenol-hydrogen peroxide reactions in skin: In vitro model relevant to study ROS reactions at inflammation2019In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 1075, p. 91-97Article in journal (Refereed)
    Abstract [en]

    Antioxidants are important to protect and maintain biological barriers, such as the skin. Antioxidant effects are often assessed using clinical trials, however these tests are costly and time consuming. In this work we introduce a skin membrane-covered oxygen electrode (SCOE) as an in vitro tool for monitoring H2O2 and antioxidant reactions in skin. The SCOE gives amperometric response to H2O2 concentrations down to 0.05 mM. More importantly, the electrode allows measurements of polyphenol penetration and reaction with H2O2 in skin. Measurements with SCOE show that lipophilic polyphenols such as quercetin, piceatannol, resveratrol, and plant extract from Plantago major impose their antioxidant effect in skin within 2-20 min. Rutin is however too hydrophilic to penetrate into stratum corneum and therefore cannot deliver its antioxidant effect during similar time interval. The measurements are interpreted considering polyphenol partition-penetration through stratum corneum and the reaction with the H2O2-catalase system in the skin. The contribution of other enzymes will be addressed in the future. (C) 2019 Elsevier B.V. All rights reserved.

  • 16.
    Esmail Tehrani, Sheida
    et al.
    Tech Univ Denmark, Natl Ctr Nano Fabricat & Characterizat, DTU Nanolab, Orsteds Plads,Bldg 347, DK-2800 Lyngby, Denmark..
    Quang Nguyen, Long
    Tech Univ Denmark, Natl Ctr Nano Fabricat & Characterizat, DTU Nanolab, Orsteds Plads,Bldg 347, DK-2800 Lyngby, Denmark..
    Garelli, Giulia
    Tech Univ Denmark, Natl Ctr Nano Fabricat & Characterizat, DTU Nanolab, Orsteds Plads,Bldg 347, DK-2800 Lyngby, Denmark..
    Jensen, Bettina M.
    Copenhagen Univ Hosp Herlev Gentofte, Allergy Clin, Gentofte Hosp Vej 8, DK-2900 Hellerup, Denmark..
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Emneus, Jenny
    Tech Univ Denmark, Dept Biotechnol & Biomed DTU Bioengn, Bldg 423, DK-2800 Lyngby, Denmark..
    Sylvest Keller, Stephan
    Tech Univ Denmark, Natl Ctr Nano Fabricat & Characterizat, DTU Nanolab, Orsteds Plads,Bldg 347, DK-2800 Lyngby, Denmark..
    Hydrogen Peroxide Detection Using Prussian Blue-modified 3D Pyrolytic Carbon Microelectrodes2021In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 33, no 12, p. 2516-2528Article in journal (Refereed)
    Abstract [en]

    A highly sensitive amperometric Prussian blue-based hydrogen peroxide sensor was developed using 3D pyrolytic carbon microelectrodes. A 3D printed multielectrode electrochemical cell enabled simultaneous highly reproducible Prussian blue modification on multiple carbon electrodes. The effect of oxygen plasma pre-treatment and deposition time on Prussian blue electrodeposition was studied. The amperometric response of 2D and 3D sensors to the addition of hydrogen peroxide in mu M and sub-mu M concentrations in phosphate buffer was investigated. A high sensitivity comparable to flow injection systems and a detection limit of 0.16 mu M was demonstrated with 3D pyrolytic carbon microelectrodes at stirred batch condition

  • 17.
    Fagerström, Anton
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Kocherbitov, Vitaly
    Malmö högskola, Faculty of Health and Society (HS).
    Lamberg, Peter
    Malmö högskola, Faculty of Health and Society (HS).
    Bergström, Karin
    Westbye, Peter
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS).
    Factors Affecting Transport of Tebuconazole over Silicone Membrane and Leaf Cuticle2010In: Proceedings of the 9th International Symposium on Adjuvants for Agrochemicals, ISAA Society , 2010, p. 329-336Conference paper (Other academic)
  • 18.
    Fagerström, Anton
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Kocherbitov, Vitaly
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Westbye, Peter
    Bergström, Karin
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Effects of surfactants and thermodynamic activity of model active ingredient on transport over plant leaf cuticle2013In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 103, p. 572-579Article in journal (Refereed)
    Abstract [en]

    The main objective of this study was to investigate the mechanism of molecular transport across the cuticle of Clivia leaves. In vitro diffusion methodology was used to investigate the transport of a systemic fungicide, tebuconazole, over a model silicone membrane, enzymatically isolated cuticle membranes, and dermatomed leaves. It was shown that dermatomed leaves may replace enzymatically isolated cuticles. Furthermore, the effects of two surfactants, C10EO7 and C8G1.6, on the fungicide transport were investigated. Tebuconazole cuticle permeation was described using Fick's first law of diffusion, expressed by the thermodynamic activity of the solute in the membrane. A new method for calculation of diffusion coefficients in the membrane is proposed. To access the thermodynamic activity of the fungicide in the membranes, sorption isotherms of tebuconazole in the membrane materials studied were recorded. The thermodynamic activity of the fungicide in aqueous solutions was calculated from solubility data. For that purpose, the effect of surfactants on tebuconazole solubility was studied. The results show that addition of surfactants allows for higher concentrations of tebuconazole available for penetration. Nonetheless, at a fixed fungicide thermodynamic activity, all formulations produced the same flux over the silicone membrane independently on the fungicide concentration. This shows that the driving force across non-responding membranes is the gradient of thermodynamic activity, rather than the gradient of the fungicide concentration. In case of leaves, surfactants induced the same quantitative increase in both flux and diffusion coefficient of solute in the cuticle, while the cuticle-water partition coefficient was unaffected.

  • 19.
    Falk, Magnus
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Alcalde, Miguel
    Bartlett, Philip
    De Lacey, Antonio
    Gorton, Lo
    Gutierrez-Sanchez, Cristina
    Haddad, Raoudha
    Kilburn, Jeremy
    Leech, Donal
    Ludwig, Roland
    Magner, Edmond
    Mate, Diana
    Conghaile, Peter
    Ortiz, Roberto
    Pita, Marcos
    Poeller, Sascha
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Salaj-Kosla, Urszula
    Schuhmann, Wolfgang
    Sebelius, Fredrik
    Shao, Minling
    Stoica, Leonard
    Sygmund, Cristoph
    Tilly, Jonas
    Toscano, Miguel
    Vivekananthan, Jeevanthi
    Wright, Emma
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Self-​powered wireless carbohydrate​/oxygen sensitive biodevice based on radio signal transmission2014In: PLOS ONE, E-ISSN 1932-6203, Vol. 9, no 10, p. e109104/1-e109104/9, article id e109104Article in journal (Refereed)
    Abstract [en]

    Here for the first time, we detail self-​contained (wireless and self-​powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-​sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and sep. sensing bioelectrodes, supplied with elec. energy from a combined multi-​enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate​/oxygen enzymic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-​contained biosensing device, employing enzyme-​modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor) and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 μA and 0.57 V, resp. to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen contg. buffer. In addn., a USB based receiver and computer software were employed for proof-​of concept tests of the developed biodevices. Operation of bench-​top prototypes was demonstrated in buffers contg. different concns. of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-​time as analyte concns. in buffers were changed, using only an enzymic fuel cell as a power supply.

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  • 20.
    Falk, Magnus
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Andoralov, Viktor
    Blum, Zoltan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sotres, Javier
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Suyatin, Dmitry
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Biofuel cell as a power source for electronic contact lenses2012In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 37, no 1, p. 38-45Article in journal (Refereed)
    Abstract [en]

    Here we present unequivocal exptl. proof that microscale cofactor- and membrane-less, direct electron transfer based enzymic fuel cells do produce significant amts. of elec. energy in human lachrymal liq. (tears). 100 μm diam. gold wires, covered with 17 nm gold nanoparticles, were used to fashion three-dimensional nanostructured microelectrodes, which were biomodified with Corynascus thermophilus cellobiose dehydrogenase and Myrothecium verrucaria bilirubin oxidase as anodic and cathodic bioelements, resp. The following characteristics of miniature glucose/oxygen biodevices operating in human tears were registered: 0.57 V open-circuit voltage, about 1 μW cm-2 max. power d. at a cell voltage of 0.5 V, and more than 20 h operational half-life. Theor. calcns. regarding the max. recoverable elec. energy can be extd. from the biofuel and the biooxidant, glucose and mol. oxygen, each readily available in human lachrymal liq., fully support our belief that biofuel cells can be used as elec. power sources for so called smart contact lenses.

  • 21.
    Falk, Magnus
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Andoralov, Viktor
    Reimann, Curt
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Srnec, Martin
    Ryde, Ulf
    Rulíšek, Lubomír
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS).
    Mechanism of Bilirubin Oxidase: Fabrication and Characterization of Efficient Biocathode2010In: Meeting abstracts (Electrochemical Society), ISSN 1091-8213, Vol. MA2010-02, no 1, article id 60Article in journal (Other academic)
    Abstract [en]

    To elucidate the mechanism of bilirubin oxidase (BOx)function in order to design efficient and stablebiocathodes working at different conditions, the enzymewas studied thoroughly. BOx is a copper-containing redoxenzyme that catalyzes the oxidation of a variety ofdifferent organic and inorganic compounds withconcomitant reduction of O2 directly to H2O.

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  • 22.
    Gari, Hala
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Rembiesa, Jadwiga
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Masilionis, Ignas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Vreda, Naida
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Svensson, Birgitta
    Sund, Torbjörn
    Hansson, Henri
    Morén, Anna Karin
    Sjöö, Malin
    Wahlgren, Marie
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Amperometric in vitro monitoring of penetration through skin membrane2015In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 27, no 1, p. 111-117Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to demonstrate that penetration of quercetin, hydrogen peroxide and ascorbic acid through skin membranes can be monitored amperometrically. Skin membrane was fixed on the top of chemically modified electrodes and penetration of the appropriate compound was registered as electrode current. The methodology allows the study of penetration from solution as well as from pharmaceutical creams. From realtime measurements of electrode current, fluxes and diffusion coefficients of mentioned compounds in skin membranes have been estimated.

  • 23.
    Gustafsson, Anna
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Prgomet, Zdenka
    Malmö University, Faculty of Odontology (OD).
    Jankovskaja, Skaidre
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ohlsson, Lars
    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.
    Effect of IFN-γ on the kynurenine/tryptophan ratio in monolayer-cultured keratinocytes and a 3D reconstructed human epidermis model2020In: Journal of dermatological science (Amsterdam), ISSN 0923-1811, E-ISSN 1873-569X, Vol. 99, no 3, p. 177-184, article id S0923-1811(20)30234-6Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Interferon-gamma (IFN-γ) represents a potent inducer for keratinocyte inflammatory and immune activation in vitro. Since tryptophan (trp) conversion to kynurenine (kyn) is involved in inflammation, the topical kyn/trp ratio may serve as a biomarker of skin inflammation. However, the trp metabolism in keratinocytes exposed to IFN-γ is not yet fully understood.

    OBJECTIVE: The aim of this study was to establish a human epidermis model in order to quantify cytokine and kyn/trp secretion from IFN-γ stimulated cells and tissues. Moreover, to compare the cell response of 2D-cultured keratinocytes and the 3D epidermis model.

    METHODS: Polycarbonate filters were used on which primary keratinocytes could attach and stratify in order to form the typical layers of reconstructed human epidermis (RHE). After IFN-γ treatment, secretion of kyn/trp was measured by high performance liquid chromatography. Gene and protein expression of indoleamine 2,3-dioxygenase 1 (IDO) was analyzed with real-time PCR and immunohistochemistry. The secretion of cytokines was quantified with ELISA.

    RESULTS: Trp catabolism to kyn was significantly increased (P < 0.01) in the 2D culture in response to IFN-γ treatment. Before kyn secretion, IDO was strongly upregulated (P < 0.001). IFN-γ treatment also increased the secretion of IL-6 and IL-8 from the keratinocytes. In the RHE, IDO was upregulated by IFN-γ, and kyn secretion could be detected. Interestingly, IDO expression was only present in the basal cells of the RHE.

    CONCLUSION: Our results suggest that IFN-γ acts as an inducer of trp degradation preferentially in undifferentiated keratinocytes, indicated by the IDO expression in the basal layer of the RHE.

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  • 24. Haberska, Karolina
    et al.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Polymer multilayer film formation studied by in situ ellipsometry and electrochemistry2009In: Bioelectrochemistry, Vol. 76, p. 153-161Article in journal (Refereed)
    Abstract [en]

    Polyelectrolyte multilayer films adsorbed on gold surfaces were studied by combined ellipsometric and electrochemical methods. Multilayers were composed of “synthetic” (poly(4-styrenesulfonic acid) ammonium salt (PSS) and poly(allylamine hydrochloride) (PAH) (PSS/PAH)) and “semi-natural” (carboxymethyl cellulose (CMC) and chitosan (CHI) (CMC/CHI)) polyelectrolytes. It was found that only PSS/PAH Layer-by-Layer (LbL) assembled structures result in dense surface confined films that limit permeability of small molecules, such as ferri-/ferrocyanide. The PSS/PAH assemblies can be envisaged as films with pinholes, through which small molecules diffuse. During the LbL deposition process of these films a number of pinholes quickly decay. A representative pinhole diameter was found to be approximately 20 μm, which determines the diffusion of small molecules through LbL films, and yet remains constant when the film consists of a few LbL assembled polyelectrolyte bilayers. CMC/CHI LbL assemblies at gold electrode surfaces give very low density films, which do not limit the diffusion of ferri-/ferrocyanide between the surface of the electrode and the solution.

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  • 25.
    Haberska, Karolina
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Svensson, Olof
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Lindh, Liselott
    Malmö högskola, Faculty of Odontology (OD).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Activity of lactoperoxidase when adsorbed on protein layers2008In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 76, no 5, p. 1159-1164Article in journal (Refereed)
    Abstract [en]

    Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paper we have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9 mg/m2. A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold.

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  • 26. Haberska, Karolina
    et al.
    Svensson, Olof
    Malmö högskola, Faculty of Health and Society (HS).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS).
    Lindh, Liselott
    Malmö högskola, Faculty of Odontology (OD).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Lactoperoxidase Activity at Gold Surfaces: Amperometric Response to Hydrogen Peroxide2008Conference paper (Other academic)
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  • 27.
    Hallan, Supandeep Singh
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy.
    Sguizzato, Maddalena
    Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy.
    Drechsler, Markus
    Bavarian Polymerinstitute “Electron and Optical Microscopy”, University of Bayreuth, D-95440 Bayreuth, Germany.
    Mariani, Paolo
    Department of Life and Environmental Sciences, Polytechnic University of Marche, I-60131 Ancona, Italy.
    Montesi, Leda
    Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy.
    Cortesi, Rita
    Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Esposito, Elisabetta
    Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy.
    The Potential of Caffeic Acid Lipid Nanoparticulate Systems for Skin Application: In Vitro Assays to Assess Delivery and Antioxidant Effect2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 1, article id E171Article in journal (Refereed)
    Abstract [en]

    The object of this study is a comparison between solid lipid nanoparticles and ethosomes for caffeic acid delivery through the skin. Caffeic acid is a potent antioxidant molecule whose cutaneous administration is hampered by its low solubility and scarce stability. In order to improve its therapeutic potential, caffeic acid has been encapsulated within solid lipid nanoparticles and ethosomes. The effect of lipid matrix has been evaluated on the morphology and size distribution of solid lipid nanoparticles and ethosomes loaded with caffeic acid. Particularly, morphology has been investigated by cryogenic transmission electron microscopy and small angle X-ray scattering, while mean diameters have been evaluated by photon correlation spectroscopy. The antioxidant power has been evaluated by the 2,2-diphenyl-1-picrylhydrazyl methodology. The influence of the type of nanoparticulate system on caffeic acid diffusion has been evaluated by Franz cells associated to the nylon membrane, while to evaluate caffeic acid permeation through the skin, an amperometric study has been conducted, which was based on a porcine skin-covered oxygen electrode. This apparatus allows measuring the O2 concentration changes in the membrane induced by polyphenols and H2O2 reaction in the skin. The antioxidative reactions in the skin induced by caffeic acid administered by solid lipid nanoparticles or ethosomes have been evaluated. Franz cell results indicated that caffeic acid diffusion from ethosomes was 18-fold slower with respect to solid lipid nanoparticles. The amperometric method evidenced the transdermal delivery effect of ethosome, indicating an intense antioxidant activity of caffeic acid and a very low response in the case of SLN. Finally, an irritation patch test conducted on 20 human volunteers demonstrated that both ethosomes and solid lipid nanoparticles can be safely applied on the skin.

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  • 28.
    Hallan, Supandeep Singh
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Sguizzato, Maddalena
    Mariani, Paolo
    Cortesi, Rita
    Huang, Nicolas
    Simelière, Fanny
    Marchetti, Nicola
    Drechsler, Markus
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Esposito, Elisabetta
    Design and Characterization of Ethosomes for Transdermal Delivery of Caffeic Acid.2020In: Pharmaceutics, ISSN 1999-4923, E-ISSN 1999-4923, Vol. 12, no 8, article id E740Article in journal (Refereed)
    Abstract [en]

    in ethosome after six months, while in water, an almost complete degradation occurred within one month. The addition of poloxamer slightly modified vesicle structure and size, while it decreased the vesicle deformability. Caffeic acid diffusion coefficients from ethosome and ethosome gel were, respectively, 137- and 33-fold lower with respect to the aqueous solution. At last, the caffeic acid permeation and antioxidant power of ethosome were more intense with respect to the simple solution.

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  • 29. Heiskanen, Arto
    et al.
    Spegel, Christer
    Kostesha, Natalie
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Emneus, Jenny
    Monitoring of Saccharomyces cerevisiae Cell Proliferation on Thiol-Modified Planar Gold Microelectrodes Using Impedance Spectroscopy2008In: Langmuir, Vol. 24, no 16, p. 9066-9073Article in journal (Refereed)
  • 30. Heiskanen, Arto
    et al.
    Spegel, Christer
    Kostesha, Natalie
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS).
    Emnéus, Jenny
    Mediator-assisted simultaneous probing of cytosolic and mitochondrial redox activity in living cells2009In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 384, no 1, p. 11-19Article in journal (Refereed)
    Abstract [en]

    This work describes an electron transfer mediator-assisted amperometric flow injection method for assessing redox enzyme activity in different subcellular compartments of the phosphoglucose isomerase deletion mutant strain of Saccharomyces cerevisiae, EBY44. The method is demonstrated using the ferricyanide-menadione double mediator system to study the effect of dicoumarol, an inhibitor of cytosolic and mitochondrial oxidoreductases and an uncoupler of the electron transport chain. Evaluation of the role of NAD(P)H-producing pathways in mediating biological effects is facilitated by introducing either fructose or glucose as the carbon source, yielding either NADH or NADPH through the glycolytic or pentose phosphate pathway, respectively. Respiratory noncompetent cells show greater inhibition of cytosolic menadione-reducing enzymes when NADH rather than NADPH is produced. Spectrophotometric in vitro assays show no difference between the cofactors. Respiratory competent cells show cytosolic inhibition only when NADPH is produced, whereas production of NADH reveals uncoupling at low dicoumarol concentrations and inhibition of complexes III and IV at higher concentrations. Spectrophotometric assays only indicate the presence of cytosolic inhibition regardless of the reduced cofactor used. This article shows the applicability of the amperometric method and emphasizes the significance of determining biological effects of chemicals in living cells.

  • 31. Hering, Kathrin
    et al.
    Björklund, Sebastian
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Klein, Stephan
    Kocherbitov, Vitaly
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Inkjet printing of surfactants, proteins and enzymes for biomedical applications2016Conference paper (Refereed)
    Abstract [en]

    Ink solutions relevant for biomedical applications have been printed using a commercial inkjet printer. Specifically, water-based inks containing surfactant, protein and enzyme have been evaluated. Printability of surfactant ink was theoretically estimated from practically determined surface tension and viscosity of the solution. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to estimate the mass of inkjet printed surfactant. The effect of printing patterns and hydration on the QCM-D data was evaluated. Finally, horseradish peroxidase ink was printed on skin and an enzymatic reaction on skin was observed. Taken together, the results from this study provide a promising starting point from which inkjet printing of protein-enzyme mixtures on skin can be evaluated.

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  • 32.
    Hernández, Aura Rocio
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Boutonnet, Marine
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Svensson, Birgitta
    Butler, Eile
    Lood, Rolf
    Blom, Kristina
    Vallejo, Bibiana
    Anderson, Chris
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    New concepts for transdermal delivery of oxygen based on catalase biochemical reactions studied by oxygen electrode amperometry2019In: Journal of Controlled Release, ISSN 0168-3659, E-ISSN 1873-4995, Vol. 306, p. 121-129Article in journal (Refereed)
    Abstract [en]

    The development of formulation concepts for improved skin tissue oxygenation, including methods for measuring oxygen (O) transport across biological barriers, are important research topics with respect to all processes that are affected by the O concentration, such as radiation therapy in oncology treatments, wound healing, and the general health status of skin. In this work we approach this topic by a novel strategy based on the antioxidative enzyme catalase, which is naturally present in the skin organ where it enables conversion of the reactive oxygen species hydrogen peroxide (HO) into O. We introduce various applications of the skin covered oxygen electrode (SCOE) as an in-vitro tool for studies of catalase activity and function. The SCOE is constructed by placing an excised skin membrane directly on an O electrode and the methodology is based on measurements of the electrical current generated by reduction of O as a function of time (i.e. chronoamperometry). The results confirm that a high amount of native catalase is present in the skin organ, even in the outermost stratum corneum (SC) barrier, and we conclude that excised pig skin (irrespective of freeze-thaw treatment) represents a valid model for ex vivo human skin for studying catalase function by the SCOE setup. The activity of native catalase in skin is sufficient to generate considerable amounts of O by conversion from HO and proof-of-concept is presented for catalase-based transdermal O delivery from topical formulations containing HO. In addition, we show that this concept can be further improved by topical application of external catalase on the skin surface, which enables transdermal O delivery from 50 times lower concentrations of HO. These important results are promising for development of novel topical or transdermal formulations containing low and safe concentrations of HO for skin tissue oxygenation. Further, our results indicate that the O production by catalase, derived from topically applied S. epidermidis (a simple model for skin microbiota) is relatively low as compared to the O produced by the catalase naturally present in skin. Still, the catalase activity derived from S. epidermidis is measurable. Taken together, this work illustrates the benefits and versatility of the SCOE as an in vitro skin research tool and introduces new and promising strategies for transdermal oxygen delivery, with simultaneous detoxification of HO, based on native or topically applied catalase.

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  • 33.
    Hernández, Aura Rocio
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Department of Pharmacy, Universidad Nacional de Colombia, Bogota 1101, Colombia.
    Vallejo, Bibiana
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    The Effect of UVB Irradiation and Oxidative Stress on the Skin Barrier: A New Method to Evaluate Sun Protection Factor Based on Electrical Impedance Spectroscopy2019In: Sensors, E-ISSN 1424-8220, Vol. 19, no 10, article id 2376Article in journal (Refereed)
    Abstract [en]

    Sunlight is vital for several biochemical processes of the skin organ. However, acute or chronic exposure to ultraviolet radiation (UVR) has several harmful effects on the skin structure and function, especially in the case of the failing function of antioxidative enzymes, which may lead to substantial tissue damage due to the increased presence of reactive oxygen species (ROS). The aim of this work was to investigate the combined effect of ultraviolet B (UVB) irradiation and oxidative stress on the skin barrier integrity. For this, we employed electrical impedance spectroscopy (EIS) to characterize changes of the electrical properties of excised pig skin membranes after various exposure conditions of UVB irradiation, oxidative stress, and the inhibition of antioxidative enzymatic processes. The oxidative stress was regulated by adding hydrogen peroxide (HO) as a source of ROS, while sodium azide (NaN) was used as an inhibitor of the antioxidative enzyme catalase, which is naturally present throughout the epidermis. By screening for the combined effect of UVB and oxidative stress on the skin membrane electrical properties, we developed a new protocol for evaluating these parameters in a simple in vitro setup. Strikingly, the results show that exposure to extreme UVB irradiation does not affect the skin membrane resistance, implying that the skin barrier remains macroscopically intact. Likewise, exposure to only oxidative stress conditions, without UVB irradiation, does not affect the skin membrane resistance. In contrast to these observations, the combination of UVB irradiation and oxidative stress conditions results in a drastic decrease of the skin membrane resistance, indicating that the integrity of the skin barrier is compromised. Further, the skin membrane effective capacitance remained more or less unaffected by UVB exposure, irrespective of simultaneous exposure of oxidative stress. The EIS results were concluded to be associated with clear signs of macroscopic tissue damage of the epidermis as visualized with microscopy after exposure to UVB irradiation under oxidative stress conditions. Finally, the novel methodology was tested by performing an assessment of cosmetic sunscreen formulations with varying sun protection factor (SPF), with an overall successful outcome, showing good correlation between SPF value and protection capacity in terms of skin resistance change. The results from this study allow for the development of new skin sensors based on EIS for the detection of skin tissue damage from exposure to UVB irradiation and oxidative stress and provide a new, more comprehensive methodology, taking into account both the influence of UVB irradiation and oxidative stress, for in vitro determination of SPF in cosmetic formulations.

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  • 34.
    Hoang, Van Chinh
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). The University of Sydney, Australia.
    Shafaat, Atefeh
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Jankovskaja, Skaidre
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gomes, V. G.
    The University of Sydney, Australia.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Franz cells for facile biosensor evaluation: A case of HRP/SWCNT-based hydrogen peroxide detection via amperometric and wireless modes2021In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 191, article id 113420Article in journal (Refereed)
    Abstract [en]

    Reducing animal use in biosensor research requires broader use of in vitro methods. In this work, we present a novel application of Franz cells suitable for biosensor development and evaluation in vitro. The work describes how Franz cell can be equipped with electrodes enabling characterization of biosensors in close proximity to skin. As an example of a sensor, hydrogen peroxide biosensor was prepared based on horseradish peroxidase (HRP)/single-walled carbon nanotube (SWCNT)-modified textile. The electrode exhibited lower detection limit of 0.3 μM and sensitivity of 184 μA mM−1 cm−2. The ability of this biosensor to monitor H2O2 penetration through skin and dialysis membranes was evaluated in Franz cell setup in amperometric and wireless modes. The results also show that catalase activity present in skin is a considerable problem for epidermal sensing of H2O2. This work highlights opportunities and obstacles that can be addressed by assessment of biosensors in Franz cell setup before progressing to their testing in animals and humans.

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  • 35. Ignatenko, O. V.
    et al.
    Sjölander, A.
    Hushpulian, D. M.
    Kazakov, S. V.
    Ouporov, I. V.
    Chubar, T. A.
    Poloznikov, A. A.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Tishkov, V. I.
    Gorton, L.
    Klyachko, N. L.
    Gazaryan, I. G.
    Electrochemistry of chemically trapped dimeric and monomeric recombinant horseradish peroxidase2013In: Advances in Biosensors and Bioelectronics, ISSN 2326-473X, Vol. 2, no 3, p. 25-34Article in journal (Refereed)
    Abstract [en]

    Native horseradish peroxidase (nHRP) exists in the aggregated form in concentrated water solutions as shown by dynamic light scattering (DLS). This is in contrast to recombinant horseradish peroxidase (recHRP) which mainly exists as a dimer. The native enzyme aggregates could be broken into the particles of nm-size only under the conditions of high ionic strength (0.5-1 M NaCl). Chemical cross-linking of recHRP with glutaraldehyde in water solutions yields 40% of the dimer. The chemically trapped dimeric and monomeric forms of recHRP were separated by gel-filtration, their substrate specificity towards a number of organic substrates compared. Parameters of direct and mediated electron transfer on graphite electrodes catalyzed by both preparations were analyzed. The difference in behavior of the monomeric and dimeric enzyme forms observed in electrochemical experiments was interpreted as a result of a “double” coverage of the electrode surface with the molecules of cross-linked dimeric enzyme, in contrast to both modified monomeric and original, unmodified recHRP providing “monolayer” coverage. In addition to the stabilization effects achieved due to enzyme surface modification with glutaraldehyde, the “double” coverage doubles the enzyme activity per surface unit.

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  • 36.
    Jankovskaja, Skaidre
    et al.
    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.
    Rezeli, Melinda
    Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund, Sweden.
    Marko-Varga, György
    Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund, Sweden.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 678Article in journal (Refereed)
    Abstract [en]

    The tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.

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  • 37.
    Jankovskaja, Skaidre
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Kamiie, Junichi
    Rezeli, Melinda
    Gustavsson, Lena
    Sugihara, Yutaka
    Miliotis, Tasso
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Marko-Varga, Gyorgy
    Optimization of sample preparation for transporter protein quantification in tissues by LC-MS/MS2018In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 164, p. 9-15Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Reproducible quantification of drug transporter protein expression in tissues is important for predicting transporter mediated drug disposition. Many mass-spectrometry based transporter protein quantification methods result in high variability of the estimated transporter quantities. Therefore, we aimed to evaluate and optimize mass spectrometry-based quantification method for drug transporter proteins in tissues. MATERIALS AND METHODS: Plasma membrane (PM) proteins from mouse tissues were isolated by applying three extraction protocols: commercial plasma membrane extraction kit, tissue homogenization by Potter-Elvehjem homogenizer in combination with sucrose-cushion ultracentrifugation, and PM enrichment with Tween 40. Moreover, five different protein digestion protocols were applied on the same PM fraction. PM isolation and digestion protocols were evaluated by measuring the amount of transporter proteins by liquid chromatography-tandem mass spectrometry in selected reaction monitoring mode. RESULTS: Mouse liver homogenization by Potter-Elvehjem homogenizer in combination with sucrose-cushion ultracentrifugation and PM enrichment with Tween 40 resulted in two times higher transporter protein quantity (Breast cancer resistance protein (Bcrp) 18.0 fmol/mug protein) in comparison with the PM samples isolated by extraction kit (Bcrp 9.8 fmol/mug protein). The evaluation of protein digestion protocols revealed that the most optimal protocol for PM protein digestion is with Lys-C and trypsin, in combination with trypsin enhancer and heat denaturation. Overall, quantities of Bcrp and Na+/K + ATPase proteins evaluated in mouse liver and kidney cortex by using our optimized PM isolation method, as well as, established digestion protocol were two to three times higher than previously reported and coefficient of variation (CV) for technical replicates was below 10%. CONCLUSION: We have established an improved transporter protein quantification methodology by optimizing PM isolation and protein digestion procedures. The optimized procedure resulted in a higher transporter protein yield and improved precision.

  • 38.
    Jankovskaja, Skaidre
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Labrousse, Anais
    Prevaud, Lea
    Holmqvist, Bo
    Brinte, Anders
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Rezeli, Melinda
    Marko-Varga, Gyorgy
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Visualisation of H2O2 penetration through skin indicates importance to develop pathway-specific epidermal sensing2020In: Microchimica Acta, ISSN 0026-3672, E-ISSN 1436-5073, Vol. 187, no 12, article id 656Article in journal (Refereed)
    Abstract [en]

    Elevated amounts of reactive oxygen species (ROS) including hydrogen peroxide (H2O2) are observed in the epidermis in different skin disorders. Thus, epidermal sensing of H2O2 should be useful to monitor the progression of skin pathologies. We have evaluated epidermal sensing of H2O2 in vitro, by visualising H2O2 permeation through the skin. Skin membranes were mounted in Franz cells, and a suspension of Prussian white microparticles was deposited on the stratum corneum face of the skin. Upon H2O2 permeation, Prussian white was oxidised to Prussian blue, resulting in a pattern of blue dots. Comparison of skin surface images with the dot patterns revealed that about 74% of the blue dots were associated with hair shafts. The degree of the Prussian white to Prussian blue conversion strongly correlated with the reciprocal resistance of the skin membranes. Together, the results demonstrate that hair follicles are the major pathways of H2O2 transdermal penetration. The study recommends that the development of H2O2 monitoring on skin should aim for pathway-specific epidermal sensing, allowing micrometre resolution to detect and quantify this ROS biomarker at hair follicles. Graphical abstract

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  • 39.
    Jankovskaja, Skaidre
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Morin, Maxim
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gustafsson, Anna
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Anderson, Chris D
    Department of Biomedical and Clinical Sciences, Linköping University, Linköping 581 83, Sweden; Department of Dermatology and Venereology, Linköping 581 83, Sweden.
    Lehoczki, Boglarka
    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.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Rezeli, Melinda
    Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund 221 00, Sweden.
    Marko-Varga, György
    Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund 221 00, Sweden.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Non-Invasive, Topical Sampling of Potential, Low-Molecular Weight, Skin Cancer Biomarkers: A Study on Healthy Volunteers.2022In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 94, no 15, p. 5856-5865Article in journal (Refereed)
    Abstract [en]

    Monitoring of low-molecular weight cancer biomarkers, such as tryptophan (Trp) and its derivative kynurenine (Kyn), might be advantageous to non-invasive skin cancer detection. Thus, we assessed several approaches of topical sampling of Trp and Kyn, in relation to phenylalanine (Phe) and tyrosine (Tyr), on the volar forearm of six healthy volunteers. The sampling was performed with three hydrogels (made of agarose or/and chitosan), hydrated starch films, cotton swabs, and tape stripping. The biomarkers were successfully sampled by all approaches, but the amount of collected Kyn was low, 20 ± 10 pmol/cm2. Kyn quantification was below LOQ, and thus, it was detected only in 20% of topical samples. To mitigate variability problems of absolute amounts of sampled amino acids, Tyr/Trp, Phe/Trp, and Phe/Tyr ratios were assessed, proving reduced inter-individual variation from 79 to 45% and intra-individual variation from 42 to 21%. Strong positive correlation was found between Phe and Trp, pointing to the Phe/Trp ratio (being in the 1.0–2.0 range, at 95% confidence) being least dependent on sampling materials, approaches, and sweating. This study leads to conclusion that due to the difficulty in quantifying less abundant Kyn, and thus the Trp/Kyn ratio, the Phe/Trp ratio might be a possible, alternative biomarker for detecting skin cancers.

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  • 40. Joon, Narender Kumar
    et al.
    He, Ning
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Bobacka, Johan
    Lisak, Grzegorz
    PVC-Based Ion-Selective Electrodes with a Silicone Rubber Outer Coating with Improved Analytical Performance2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 16, p. 10524-10531Article in journal (Refereed)
    Abstract [en]

    An outer layer of pure silicone rubber (SR), i.e. SR without any plasticizer, ionophore, or lipophilic anion, was applied on top of a conventional poly(vinyl chloride) (PVC) based K+-selective membrane in a solid-contact ion-selective electrode (SC-ISE). The influence of the outer SR coating on the analytical performance of the K+-ISEs was studied. The presence of the SR coating did not affect the selectivity of the SC-ISE, indicating that the plasticizer, ionophore, and lipophilic anion are spontaneously distributed from the PVC-based membrane into the SR layer. This was confirmed by electrochemical impedance spectroscopy (EIS). Interestingly, the reproducibility of the standard potential of the conditioned SC-ISE was significantly improved from E-0 +/- 35.3 mV to E-0 +/- 3.5 mV simply by adding the SR coating on top of the plasticized PVC based K+-selective membrane. Moreover, the adsorption of bovine serum albumin (BSA) was significantly reduced at the SR coated ion-selective membrane. Thus, the addition of a SR coating on a plasticized PVC ion-selective membrane seems to be a feasible method to improve the analytical performance and to reduce the biofouling of potentiometric ion sensors.

  • 41.
    Kalimuthu, Palraj
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Gonzalez-Martinez, Juan F
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Jakubauskas, Dainius
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sotres, Javier
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Battery-free radio frequency wireless sensor for bacteria based on their degradation of gelatin-fatty acid composite films2021In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 381, article id 138275Article in journal (Refereed)
    Abstract [en]

    Continuous and automated bacteria detection is pivotal for a myriad of biomedical, food safety and envi-ronmental applications. This work presents the fabrication of a prototype of a passive (battery-free) radio frequency sensor for wireless detection of bacteria. The sensing mechanism is based on the bacterial-induced (proteases and peptidases) degradation of glutaraldehyde (GTA) cross-linked gelatin-caprylic acid (CA) composite film. Proteolytic degradation of the film resulted in a decrease of its resistivity, a quan-tity that could be wirelessly monitored by coupling the film to a radio-frequency antenna (an inductor-capacitor resonator) and monitoring the frequency for which the transferred power between this antenna and another antenna connected to a Vector Network Analyzer (VNA) was maximized. We experimen-tally proved this concept by monitoring E.coli bacteria in aqueous medium and detected at 18.0 +/- 2.8 h, 23.5 +/- 0.7 h, 27.0 +/- 2.8 h, 40.5 +/- 3.5 h, 45.5 +/- 0.7 h for the initial E.coli concentration of 3.2 +/- 10(8) , 6.8 +/- 10(7) , 2.3 +/- 10(6) , 4.3 +/- 10(5) , and 3.6 +/- 10(4) CFU/mL, respectively. Further, the E.coli induced degrada-tion of the composite film was investigated by evaluating the thickness of the film by optical microscopy as well as morphology by scanning electron microscopy techniques. (C) 2021 Published by Elsevier Ltd.

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  • 42.
    Kalimuthu, Palraj
    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.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sotres, Javier
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Highly Stable Passive Wireless Sensor for Protease Activity Based on Fatty Acid-Coupled Gelatin Composite Films.2020In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 92, no 19, p. 13110-13117Article in journal (Refereed)
    Abstract [en]

    Proteases are often used as biomarkers of many pathologies as well as of microbial contamination and infection. Therefore, extensive efforts are devoted to the development of protease sensors. Some applications would benefit from wireless monitoring of proteolytic activity at minimal cost, e.g., sensors embedded in care products like wound dressings and diapers to track wound and urinary infections. Passive (batteryless) and chipless transponders stand out among wireless sensing technologies when low cost is a requirement. Here, we developed and extensively characterized a composite material that is biodegradable but still highly stable in aqueous media, whose proteolytic degradation could be used in these wireless transponders as a transduction mechanism of proteolytic activity. This composite material consisted of a cross-linked gelatin network with incorporated caprylic acid. The digestion of the composite when exposed to proteases results in a change of its resistivity, a quantity that can be wirelessly monitored by coupling the composite to an inductor-capacitor resonator, i.e., an antenna. We experimentally proved this wireless sensor concept by monitoring the presence of a variety of proteases in aqueous media. Moreover, we also showed that detection time follows a relationship with protease concentration, which enables quantification possibilities for practical applications.

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  • 43. Krikstolaityte, Vida
    et al.
    Barrantes, Alejandro
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ramanavicius, Arunas
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Bioelectrocatalytic reduction of oxygen at gold nanoparticles modified with laccase2014In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 95, p. 1-6Article in journal (Refereed)
    Abstract [en]

    To characterise bioelectrocatalytic oxygen reduction at gold nanoparticles (AuNPs) modified with Trametes hirsuta laccase (ThLc) combined electrochemical and quartz crystal microbalance measurements have been used. The electrodes with different degrees of AuNP-monolayer coverage, theta, have been studied. In every case of theta close to theoretically possible 44 ThLc molecules adsorbed at 22 nm diameter AuNP. The bioelectrocatalytic current was recalculated down to the current at a single AuNR Unexpectedly, the current at a single AuNP was higher when theta was higher. The maximum current reached at a single AuNP was 31.10(-18) A which corresponds to the enzyme turnover (k(cat)) 13 s(-1). This rate is lower than the homogeneous ThLc turnover (190 s(-1)) suggesting partial denaturation of ThLc upon adsorption or that some ThLc are not in DET contact with the electrode surface

  • 44. Krikstolaityte, Vida
    et al.
    Ding, Ruiyu
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lisak, Grzegorz
    Characterization of nano-layered solid-contact ion selective electrodes by simultaneous potentiometry and quartz crystal microbalance with dissipation.2020In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 1128, p. 19-30, article id S0003-2670(20)30692-9Article in journal (Refereed)
    Abstract [en]

    Nano-layered solid-contact potassium-selective electrodes (K+-ISEs) were explored as model ion-selective electrodes for their practical use in clinical analysis. The ultra-thin ISEs ought to be manufactured in a highly reproducible manner, potentially making them suitable for mass production. Thus, their development is pivotal towards miniaturised sensors with simplified conditioning/calibration protocols for point-of-care diagnostics. To study nano-layered ISEs, the ultra-thin nature of ISEs for the first time enabled to combine potentiometry-quartz crystal microbalance with dissipation (QCM-D) to obtain value-added information on the ISE potentiometric response regarding their physical state such as mass/thickness/viscoelastic properties/structural homogeneity. Specifically, the studies were focused on real-time observations of the ISE potentiometric response in relation to changes of their physicochemical properties during the ISE preparation (conditioning) and operation (including biofouling conditions) to identify the occurring processes that may accordingly be critical for potential instability of the ISEs, impeding their practical application. The K+-ISEs were prepared on a QCM-D gold sensor by electrodepositing poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) layer serving as an ion-to-electron transducer subsequently covered by a spin-coated poly(vinyl chloride) based K+-ion selective membrane (K+-ISM). The studies demonstrated that the performance of the nano-layered design of K+-ISEs is detrimentally affected by such processes as water layer formation accordingly causing the instability of the electrode potential. The changes in the ISE physical state such mass/viscoelastic properties associated with water layer formation and origin of the potential instability was already observed at the ISE conditioning stage. The potential instability of nano-layered ISEs limits their practical applicability, indicating the need of new solutions in designing ISEs, for instance, exploiting new water-resistant materials and modifying preparation protocols.

  • 45.
    Krikstolaityte, Vida
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, 639798 Singapore, Singapore; Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, CleanTech One, 637141Singapore, Singapore.
    Hamit-Eminovski, Jildiz
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Abariute, Laura
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Solid State Physics, NanoLund, Lund University, 221 00 Lund, Sweden.
    Niaura, Gediminas
    Meskys, Rolandas
    Arnebrant, Thomas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lisak, Grzegorz
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Impact of molecular linker size on physicochemical properties of assembled gold nanoparticle mono-/multi-layers and their applicability for functional binding of biomolecules2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 543, p. 307-316Article in journal (Refereed)
    Abstract [en]

    In this work the impact of molecular inter-linker size on gold nanoparticle (AuNP) mono-/multilayer structural properties, density and homogeneity has been investigated. These characteristics are of great importance for functional binding of biomolecules. Positively charged high or low molecular weight inter-linkers, poly-L-lysine (PLL) or N-(6-mercapto)hexylpyridinium (MHP), were used to attach negatively charged AuNPs on a planar gold surface as well as to further interlink into a multilayer structure via layer-by-layer deposition. The inter-particle interaction within the assembled AuNP films was adjusted by the ionic strength in the AuNPs dispersions The AuNP layer density and structural/viscoelastic properties were evaluated by the quartz crystal microbalance with dissipation (QCM-D) technique. The validity of the commercial Voigt model, specifically developed for quantitative QCM-D data analysis of homogeneous viscoelastic films, was evaluated by a model independent analysis when comparing the assembled AuNP films with a homogeneous layer of a mucin from bovine submaxillary glands. Both AuNP mono- and multilayers, attached/interlinked via long flexible PLL molecules assembled to denser and more soft/viscous structures compared to those interlinked by short MHP compounds. Thus, PLL-interlinked AuNP mono-/multilayer structures were further investigated as a platform for laccase enzyme functional adsorption via qualitative assessment of bioelectrochemical characteristics of the enzyme. (C) 2019 Elsevier Inc. All rights reserved.

  • 46. Krikstolaityte, Vida
    et al.
    Lamberg, Peter
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Toscano, Miguel
    Silow, Maria
    Eicher-Lorka, Olegas
    Ramanavicius, Arunas
    Niaura, Gediminias
    Abairute, Laura
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Mediatorless Carbohydrate​/Oxygen Biofuel Cells with Improved Cellobiose Dehydrogenase Based Bioanode2014In: Fuel Cells, ISSN 1615-6846, E-ISSN 1615-6854, Vol. 14, no 6, p. 792-800Article in journal (Refereed)
    Abstract [en]

    Direct electron transfer (DET) between cellobiose dehydrogenase from Humicola insolens ascomycete (HiCDH) and gold nanoparticles (AuNPs) was achieved by modifying AuNPs with a novel, pos. charged thiol N-​(6-​mercapto)​hexylpyridinium (MHP)​. The DET enabled the use of the HiCDH enzyme as an anodic biocatalyst in the design of a mediatorless carbohydrate​/oxygen enzymic fuel cell (EFC)​. A biocathode of the EFC was based on bilirubin oxidase from Myrothecium verrucaria (MvBOx) directly immobilized on the surface of AuNPs. The following parameters of the EFC based on Au​/AuNP​/MHP​/HiCDH bioanode and Au​/AuNP​/MvBOx biocathode were obtained in quiescent air satd. PBS, pH 7.4, contg.: (i) 5 mM glucose-​open-​circuit voltage (OCV) of 0.65 ± 0.011 V and the maximal power d. of 4.77 ± 1.34 μW cm-​2 at operating voltage of 0.50 V; or (ii) 10 mM lactose-​OCV of 0.67 ± 0.006 V and the maximal power d. of 8.64 ± 1.91 μW cm-​2 at operating voltage of 0.50 V. The half-​life operation times of the EFC were estd. to be at least 13 and 44 h in air satd. PBS contg. 5 mM glucose and 10 mM lactose, resp. Among advantages of HiCDH​/MvBOx FCs are (i) simplified construction, (ii) relatively high power output with glucose as biofuel, and (iii) the absence of the inhibition of the HiCDH based bioanode by lactose, when compared with the best previously reported CDH based bioanode.

  • 47. Krikstolaityte, Vida
    et al.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Heiskanen, Arto
    Canali, Chiara
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Emneus, Jenny
    Development of a plastic membrane containing micro-hole(s) for a potential bio-sensing application2017In: Procedia Technology, E-ISSN 2212-0173, Vol. 27, no Special Issue Biosensors 2016, p. 252-253Article in journal (Refereed)
    Abstract [en]

    In this work, a poly (methyl methacrylate) membrane containing micro-holes (MHs) as a prototype of a simple sensing platform of a lab-on-a-chip device has been developed for a potential analysis of clinical fluidic samples. A four probe electrochemical impedance spectroscopy (EIS) setup, with two electrodes placed on each side of the membrane, was adopted for monitoring the MH impedance (Fig. 1a). The setup was used to investigate, if EIS is suitable to sense the trapping of an analyte inside the MHs. Latex micro-beads with a diameter of 10 mu m were used to test clogging of the MHs. Additionally, finite element model simulations were performed using Comsol Multiphysics software to theoretically evaluate the sensitivity field of the EIS measurement along the MHs. (C) 2017 The Authors. Published by Elsevier Ltd.

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  • 48.
    Kumlien, Christine
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Care Science (VV). Skane Univ Hosp, Dept Cardiothorac & Vasc Surg, Malmo, Sweden..
    Acosta, Stefan
    Skane Univ Hosp, Dept Cardiothorac & Vasc Surg, Malmo, Sweden.;Lund Univ, Dept Clin Sci, Malmo, Sweden..
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lavant, Eva
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lazer, Victoria
    Malmö University, Faculty of Health and Society (HS), Department of Care Science (VV).
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Gershater, Magdalena
    Malmö University, Faculty of Health and Society (HS), Department of Care Science (VV).
    Research priorities to prevent and treat diabetic foot ulcers-A digital James Lind Alliance Priority Setting Partnership2022In: Diabetic Medicine, ISSN 0742-3071, E-ISSN 1464-5491, Vol. 39, no 11, article id e14947Article in journal (Refereed)
    Abstract [en]

    Aim To establish outcomes of a priority setting partnership between participants with diabetes mellitus and clinicians to identify the top 10 research priorities for preventing and treating diabetic foot ulcers (DFUs). Methods Due to the COVID-19 pandemic, the James Lind Alliance Priority Setting Partnership process was adapted into a digital format which involved a pilot survey to identify understandable uncertainties with high relevance for participants tested by calculating the content validity index; a main survey answered by 53 participants living with diabetes and 49 clinicians; and a final digital workshop to process and prioritise the final top 10 research priorities. Results The content validity index was satisfactory for 20 out of 25 uncertainties followed by minor changes and one additional uncertainty. After we processed the 26 uncertainties from the main survey and seven current guidelines, a list of 28 research uncertainties remained for review and discussion in the digital workshop. The final top 10 research priorities included the organisation of diabetes care; screening of diabetes, impaired blood circulation, neuropathy, and skin properties; vascular surgical treatment; importance of self-care; help from significant others; pressure relief; and prevention of infection. Conclusion The top 10 research priorities for preventing and treating DFUs represent consensus areas from persons living with diabetes and clinicians to guide future research. These research priorities can justify and inform strategic allocation of research funding. The digitalisation of James Lind Alliance methodology was feasible.

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    fulltext
  • 49.
    Lamberg, P.
    et al.
    Department of Chemistry, University of Rochester, 14611 Rochester, NY, USA.
    Hamit-Eminovski, J.
    CMC Diabetes Formulation Development, Novo Nordisk, Novo Alle Bagsvaerd, 2880, Denmark.
    Toscano, M. D.
    Protein Engineering, Novozymes A/S, Bagsvaerd 2880, Denmark.
    Eicher-Lorka, O.
    Department of Organic Chemistry, Center for Physical Sciences and Technology, Sauletekio av. 3, LT-10257 Vilnius, Lithuania.
    Niaura, G.
    Department of Organic Chemistry, Center for Physical Sciences and Technology, Sauletekio av. 3, LT-10257 Vilnius, Lithuania.
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Electrical activity of cellobiose dehydrogenase adsorbed on thiols: Influence of charge and hydrophobicity2017In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 115, p. 26-32Article in journal (Refereed)
    Abstract [en]

    The interface between protein and material surface is of great research interest in applications varying from implants, tissue engineering to bioelectronics. Maintaining functionality of bioelements depends greatly on the immobilization process. In the present study direct electron transfer of cellobiose dehydrogenase from Humicola insolens (HiCDH), adsorbed on four different self-assembled monolayers (SAMs) formed by 5-6 chain length carbon thiols varying in terminal group structure was investigated. By using a combination of quartz crystal micro balance with dissipation, ellipsometry and electrochemistry the formation and function of the HiCDH film was studied. It was found that the presence of charged pyridinium groups was needed to successfully establish direct electron contact between the enzyme and electrode. SAMs formed from hydrophilic charged thiols achieved nearly two times higher current densities compared to hydrophobic charged thiols. Additionally, the results also indicated proportionality between HiCDH catalytic constant and water content of the enzyme film. Enzyme films on charged pyridine thiols had smaller variations in water content and viscoelastic properties than films adsorbed on the more hydrophobic thiols. This work highlights several perspectives on the underlying factors affecting performance of immobilized HiCDH. (C) 2017 Elsevier B.V. All rights reserved.

  • 50.
    Lamberg, Peter
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Shleev, Sergey
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ludwig, Roland
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Performance of enzymatic fuel cell in cell culture2014In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 55, p. 168-173Article in journal (Refereed)
    Abstract [en]

    Here we present the very first study of an enzymatic fuel cell (EFC) in a cell culture. An EFC with Corynascus thermophilus cellobiose dehydrogenase (CDH) based bioanode and Myrothecium verrucaria bilirubin oxidase (Box) based biocathode was constructed at the bottom of a medusa cell culture plate. The constructed EFC had a power density of up to 25 mu W cm(-2) at 0.5 V potential in simple buffer solution and in cell culturing medium. L929 murine fibroblast cells were seeded on top of the EFC and possible effects of the EFC on the cells and vice versa were studied. It was shown that on average the power of the EFC drops by about 70% under a nearly confluent layer of cells. The EFC appeared to have a toxic effect on the L929 cell line. It was concluded that the bioanode, consisting of CDH, produced hydrogen peroxide at toxic concentrations. However, the toxic effect was circumvented by co-immobilizing catalase on the bioanode.

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