University Medical Center Jena

Jena, Germany

University Medical Center Jena

Jena, Germany
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Finger S.,University Medical Center Jena | Wiegand C.,University Medical Center Jena | Buschmann H.-J.,German Textile Research Center North - West | Hipler U.-C.,University Medical Center Jena
International Journal of Pharmaceutics | Year: 2013

Cyclodextrins (CDs) are able to form inclusion complexes with other molecules, thereby, protecting these guest molecules from degradation, enhancing their biocompatibility or influencing their physiological distribution while retaining their activity. Here, antibacterial effects of CD-complexes with the antiseptics chlorhexidine diacetate (CHX), iodine (IOD) and polihexanide (PHMB) were determined using two different in vitro methods, microplate laser nephelometry and an ATP bioluminescence assay. Laser nephelometry is a direct method for monitoring and evaluating growth of micro-organisms by measurement of the turbidity of the solution. In contrast, the ATP bioluminescence assay determines specifically the amount of metabolic active bacterial cells. The antibacterial effects of CD-antiseptics-complexes were examined for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis and the results of both methods were compared in respect of calculated means of half maximal inhibitory concentrations (IC 50) and statistical evaluated Pearson's correlation coefficients (r). It could be demonstrated that both methods showed a high comparability although they differ in the parameters tested. This study revealed that CD-complexes with CHX and PHMB were most effective against E. coli and the tested staphylococci. While CD-IOD-complexes obtained high activity against K. pneumoniae, P. aeruginosa was distinctly more resistant compared to the other bacteria. © 2013 Elsevier B.V. All rights reserved.

Finger S.,University Medical Center Jena | Wiegand C.,University Medical Center Jena | Buschmann H.-J.,German Textile Research Center North - West | Hipler U.-C.,University Medical Center Jena
International Journal of Pharmaceutics | Year: 2012

Antimicrobial effects of substances can be determined with different methods that measure distinct parameters. Thus, a comparison of the results obtained can be difficult. In this study, two in vitro methods were employed to determine concentration and time dependent effects of cyclodextrin (CD)-complexes with the antiseptics chlorhexidine diacetate (CHX), iodine (IOD) and polihexanide (PHMB) on Candida albicans and Malassezia pachydermatis. Using both, microplate laser nephelometry and the ATP bioluminescence assay, it could be shown that CD-antiseptics-complexes tested exhibited significant antifungal effects with the exception of γ-CD-CHX in the case of C. albicans. Microplate laser nephelometry (MLN) is an optical method and enables a quantitative determination of particle concentrations in solution. By means of this method, microbial growth under influence of potential antimicrobial substances can be monitored over a prolonged time period. In addition, the antimicrobial activity was analyzed by measurement of the microbial adenosine triphosphate (ATP) content with a bioluminescent assay. The luminescent signal is directly proportional to the amount of ATP, and thus, a linear function of the number of living microbial cells present. Both methods were compared according to the half maximal inhibitory concentration (IC50) calculated and the statistical evaluation of Pearson's correlation coefficient (r). In summary, it could be demonstrated that both methods yield similar results although they differ in the parameter. © 2012 Elsevier B.V. All rights reserved.

Roemhild K.,Thuringian Institute of Textile and Plastics Research E.V. | Wiegand C.,University Medical Center Jena | Hipler U.-C.,University Medical Center Jena | Heinze T.,Friedrich - Schiller University of Jena
Macromolecular Rapid Communications | Year: 2013

Amino-cellulose-based nanofibers are prepared by electrospinning of blended solutions of 6-deoxy-6-trisaminoethyl-amino (TEAE) cellulose and polyvinyl alcohol (PVA). The TEAE cellulose with a degree of substitution of 0.67 is synthesized via a nucleophilic displacement reaction starting from cellulose-p-toluenesulfonic acid ester. Several solution characteristics such as polymer concentration, electrical conductivity, and surface tension as well as setup parameters are investigated to optimize the ability of nanofiber formation. These parameters are evaluated using the rheological studies of the solutions. The nanofibers obtained are characterized by scanning electron microscopy (SEM) and show a high antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae. The electrospinning of amino-functionalized cellulose yielding nanofibrous materials opens up new fields of applications for this interesting class of cellulose derivatives. The 6-deoxy-6- triaminotriethylamino (TEAE) cellulose-based nanofiber webs exhibit strong antimicrobial activities. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Berndt S.,Friedrich - Schiller University of Jena | Wesarg F.,Friedrich - Schiller University of Jena | Wiegand C.,University Medical Center Jena | Kralisch D.,Friedrich - Schiller University of Jena | Muller F.A.,Friedrich - Schiller University of Jena
Cellulose | Year: 2013

The increasing resistance of pathogens and bacteria is a serious problem in the medical treatment of wounds and injuries. Therefore, new therapeutic agents are not solely based on antibiotics, but also on the use of antimicrobial metal nanoparticles. In this paper we present an innovative method to prepare porous hybrids consisting of bacterial nanocellulose (BNC) and silver nanoparticles (AgNPs). The stepwise modification is based on fairly simple chemical reactions already described for two-dimensional cellulose films. We transferred this method to the three-dimensional, porous network of BNC leading to an antimicrobial activation of its surface. Compared to former approaches, the ultrafine network structure of BNC is less damaged by using mild chemicals. The amount and distribution of the AgNPs on the modified BNC was investigated using scanning electron microscopy. The AgNPs are firmly immobilized on the top and bottom surface of the BNC by chemical interactions. Their size and quantity increase with an increasing concentration of AgNO3 and extended reaction time in the AgNO3 solution. A strong antimicrobial activity of the BNC-AgNP hybrids against Escherichia coli was detected. Furthermore, agar diffusion tests confirmed that this activity is restricted to the modified dressing itself, avoiding a release of NPs into the wound. Therefore, the produced hybrids could be potentially suited as novel antimicrobial wound dressings. © 2013 Springer Science+Business Media Dordrecht.

Wiegand C.,University Medical Center Jena | White R.,University of Worcester
Wound Repair and Regeneration | Year: 2013

Mechanical forces greatly influence cellular organization and behavior. Cells respond to applied stress by changes in form and composition until a suitable state is reestablished. However, without any mechanical stimuli cells stop proliferating, discontinue migration, go into cell-cycle arrest, and eventually die. Hence, one can assume that pathologies closely depending on cell migration like cancer or atherosclerosis might be governed by biophysical parameters. Moreover, mechanical cues will have fundamental effects in wound healing. Especially negative pressure wound therapy has the potential to endorse wound healing by induction of both macrodeformation (wound contraction) and microdeformation (tissue reactions at microscopic level). So far, the capacity for researchers to study the link between mechanical stimulation and biological response has been limited by the lack of instrumentation capable of stimulating the tissue in an appropriate manner. However, first reports on application of micromechanical forces to wounds elucidate the roles of cell stretch, substrate stiffness, and tissue deformation during cell proliferation and differentiation. This review deals with their findings and tries to establish a link between the current knowledge and the questions that are essential to clinicians in the field: What is the significance of mirodeformations for wound healing? Does "dead space" impede propagation of mechanical cues? How can microdeformations induce cell proliferation? What role do fibroblasts, myofibroblasts, and mesenchymal stem cells play in chronic wounds with regard to micromechanical forces? © 2013 by the Wound Healing Society.

Wiegand C.,University Medical Center Jena
International journal of pharmaceutics | Year: 2013

Cationic polyamines, such as poly(ethyleneimines) (PEIs), may recommend themselves for antimicrobial applications as they can interact with microbial membranes resulting in their disruption. The purpose of the study was the assessment of biocompatibility and antibacterial activity of PEIs with different architectures (branched (b) and linear (l)) and molar masses (0.8-750 kDa). lPEI and bPEI exhibited a strong antibacterial activity against Staphylococcus aureus and Escherichia coli with a more pronounced effect on the Gram-positive bacteria. lPEIs further demonstrated a higher antibacterial efficacy compared to bPEIs but no significant differences between 5 and 25 kDa were observed. In accordance, antibacterial activity of bPEI did not specifically depend on molar mass. Only slightly lower minimal inhibitory concentrations (MIC) were observed at 5 kDa (S. aureus) and 25 kDa (E. coli) in the tests. As PEIs are compelling candidates for use in antimicrobial treatment, two basic aspects have to be investigated: treatment effectiveness and safety. PEIs clearly induced molecular weight dependent cytotoxic effects in vitro. PEIs with low molecular weight (0.8 and 5 kDa) exhibited higher biocompatibility. Nonetheless, the results confirmed a low genotoxic potential of lPEI and bPEIs. In conclusion, 2.5 kDa-lPEI and 0.8 kDa-bPEI can be recommended for use as antimicrobial polymers in dermal applications due to their high biocompatibility with concomitant antibacterial efficacy. Copyright © 2013 Elsevier B.V. All rights reserved.

Wiegand C.,University Medical Center Jena | Hipler U.-C.,University Medical Center Jena | Boldt S.,Academic Teaching Hospital Dresden Friedrichstadt | Strehle J.,Academic Teaching Hospital Dresden Friedrichstadt | Wollina U.,Academic Teaching Hospital Dresden Friedrichstadt
Clinical, Cosmetic and Investigational Dermatology | Year: 2013

Atopic dermatitis (AD) is a chronic inflammatory disease characterized by the impairment of the skin-barrier function, increased oxidative cellular stress, and bacterial colonization. Hence, medical therapies of AD aim to control infection, reduce inflammation, and restore skin-barrier function by use of topical and systemic antibacterial drugs, topical corticosteroids, topical calcineurin inhibitors, and moisturizers. Textiles have the longest and most intense contact with the human skin, and functional textiles with intrinsic properties such as antioxidative capacity and antibacterial activity have been gaining in importance in medical applications. Specially designed textiles may support AD treatment and improve quality of life of AD. Here, we investigated the role of ZnO-functionalized textile fibers in the control of oxidative stress in AD in vitro and in vivo. In addition, the antibacterial effect and biocompatibility of the Zn textile was evaluated in vitro. We observed a rapid improvement of AD severity, pruritus, and subjective sleep quality when AD patients wore the ZnO textiles overnight on 3 consecutive days. This is possibly due to the high antioxidative capacity of the ZnO textile, as well as the allocation of strong antibacterial activity. Moreover, it was shown that the ZnO textiles possess very good biocompatibility and were well tolerated by AD patients. © 2013 Wiegand et al.

Wiegand C.,University Medical Center Jena | Hipler U.-C.,University Medical Center Jena
Macromolecular Symposia | Year: 2010

Chronic wounds, such as venous, pressure, and diabetic ulcers, are difficult to heal and represent a rising social and economical problem. Compared to acute wounds, non-healing wounds contain elevated levels of neutrophil elastase, pro-inflammatory cytokines (IL-1β, IL-6, IL-8), and matrix metalloproteases (MMP-2, MMP-9, MMP-1β) as well as free radicals. Their overproduction perpetuates the inflammatory phase resulting in severe tissue damage and degradation of growth factors. Consequently, wound closure is prevented and the wound remains non-healing for month or even years. The increasing numbers of patients suffering from wounds that fail to heal are a significant challenge for health care professionals. Wound dressings play an important role in the entire management of these wounds. New materials and treatment strategies are needed to improve wound care. Recent advances in the field of biomaterials and their medical applications indicate the significance and potential of various natural polymers in the development of novel classes of wound dressings. Native polymers are an ideal source for bio-active wound dressings because of their availability and biocompatibility. Hence, several studies have been conducted to explore the influence of wound dressings consisting of collagen, oxidized regenerated cellulose, bacterial cellulose, chitosan, or alginate on the destructive milieu in chronic wounds. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wiegand C.,University Medical Center Jena | Hipler U.-C.,University Medical Center Jena
Journal of Materials Science: Materials in Medicine | Year: 2013

Superabsorbent polymer (SAP)-containing wound dressings present a valuable and unique category of wound management products. An in vitro approach was used to assess the effects of a new SAP dressing in treatment of non-healing wounds. It was shown that the SAP dressing possesses a significant binding capacity for MMP-2 and MMP-9 in vitro (P < 0.001). The inclusion of the bound proteases was so strong that no MMP-2 and only marginal amounts of MMP-9 were released from the dressing samples in a subsequent elution step. In addition, the SAP dressing was able to take up collagenase and reduce its activity in vitro. However, collagenase was not completely inactivated upon binding and enzyme-mediated substrate turnover could be observed at the dressings. In conclusion, in vitro data confirm the positive effect of the SAP wound dressing observed in vivo. The findings suggest that it should be specifically useful for highly exuding wounds with an elevated proteolytic activity that needs to be reduced to support healing. © 2013 The Author(s).

Wiegand C.,University Medical Center Jena | Winter D.,University Medical Center Jena | Hipler U.-C.,University Medical Center Jena
Skin Pharmacology and Physiology | Year: 2010

The cationic polysaccharide chitosan possesses bioactive properties such as antimicrobial activity, antitumor effects, hemostatic assets and positive effects on wound healing. The influence of polycations like chitosan on human cells has been reported to depend on their molecular weight. However, the mechanism of cytotoxicity caused by polycations is not yet fully understood. In the study presented, the influence of two chitosans with a similar degree of deacetylation but different molecular weight, chitosan 1130 (120 kDa) and chitosan oligosaccharide (5 kDa), on the human keratinocyte cell line HaCaT was analyzed. The results obtained indicate that chitosans exhibit a molecular-weight-dependent negative effect on HaCaT cell viability and proliferation in vitro. The chitosans tested also stimulated the release of inflammatory cytokines by HaCaT cells depending on incubation time and concentration. Chitosan 1130 and chitosan oligosaccharide induced apoptotic cell death which was mediated by activation of the effector caspases 3/7. At least for chitosan 1130, the involvement of both, extrinsic and intrinsic signal pathways, was shown by activation of caspases 8 and 9. © 2010 S. Karger AG, Basel.

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