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Your search keyword '"G. Björn Stark"' showing total 2 results
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2 results on '"G. Björn Stark"'

1. Evaluation of a Novel Thiol–Norbornene-Functionalized Gelatin Hydrogel for Bioprinting of Mesenchymal Stem Cells

Author

Vadym Burchak, Fritz Koch, Leonard Siebler, Sonja Haase, Verena K. Horner, Xenia Kempter, G. Björn Stark, Ute Schepers, Alisa Grimm, Stefan Zimmermann, Peter Koltay, Sandra Strassburg, Günter Finkenzeller, Filip Simunovic, and Florian Lampert

Subjects
cartilage, hydrogel, bioprinting, mesenchymal stem cells, differentiation, biocompatibility, Biology (General), QH301-705.5, Chemistry, QD1-999
Abstract

Introduction: Three-dimensional bioprinting can be considered as an advancement of the classical tissue engineering concept. For bioprinting, cells have to be dispersed in hydrogels. Recently, a novel semi-synthetic thiolene hydrogel system based on norbornene-functionalized gelatin (GelNB) and thiolated gelatin (GelS) was described that resulted in the photoclick hydrogel GelNB/GelS. In this study, we evaluated the printability and biocompatibility of this hydrogel system towards adipose-tissue-derived mesenchymal stem cells (ASCs). Methods: GelNB/GelS was synthesized with three different crosslinking densities (low, medium and high), resulting in different mechanical properties with moduli of elasticity between 206 Pa and 1383 Pa. These hydrogels were tested for their biocompatibility towards ASCs in terms of their viability, proliferation and differentiation. The extrusion-based bioprinting of ASCs in GelNB/GelS-high was performed to manufacture three-dimensional cubic constructs. Results: All three hydrogels supported the viability, proliferation and chondrogenic differentiation of ASCs to a similar extent. The adipogenic differentiation of ASCs was better supported by the softer hydrogel (GelNB/GelS-low), whereas the osteogenic differentiation was more pronounced in the harder hydrogel (GelNB/GelS-high), indicating that the differentiation fate of ASCs can be influenced via the adaption of the mechanical properties of the GelNB/GelS system. After the ex vivo chondrogenic differentiation and subcutaneous implantation of the bioprinted construct into immunocompromised mice, the production of negatively charged sulfated proteoglycans could be observed with only minimal inflammatory signs in the implanted material. Conclusions: Our results indicate that the GelNB/GelS hydrogels are very well suited for the bioprinting of ASCs and may represent attractive hydrogels for subsequent in vivo tissue engineering applications.

Published
2022
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2. Autologous skin micro-grafts and allogenic skin allograft for mitten hand deformity treatment in epidermolysis bullosa

Author

Nico Leibig, G. Björn Stark, Horst Zajonc, Marcel Frick, Dimitra Kiritsi, and Florian M. Lampert

Subjects
integumentary system
Abstract

Background: In the genetic skin blistering disorder dystrophic epidermolysis bullosa recurrent blisters and erosions on mechanically stressed areas, as the hands, result in subsequent scarring and development of pseudosyndactylies and contractures. In its most severe form, all fingers are constrained into a fist of scarred (“mitten-hand”-deformity). No causative therapy exists and only a surgical release of the fingers is possible. Hereby, the development of large skin defects is inevitable; the lack of healthy autologous skin for grafting remains a difficult challenge.Methods: We propose a new technique: It adopts a treatment strategy from the therapy of large extent burns and consists of a combination of autogenic and allogenic skin grafting.Results: We present a beneficial outcome in 18 mitten hand deformities treated with this technique. In all patients, the initial functional outcome was improved. Nearly all patients got a considerably widened grip span and durable skin conditions post-operatively. Mean follow-up was 3 years. Typically, recurrence of the scarring occurred from 6 months to 2 years after operation.Conclusions: This is the first report on the use of the combination of autogenous pinch skin grafts with allogenic (parental) skin overlay for skin defects in EB. It provides undisturbed wound healing under a “biological dressing”, furthermore, a temporary take of the parental skin was visible. Defects were permanently covered with skin of increased mechanical stability, hand function improved remarkably. However, long term follow-up showed beginning recurrence in most of the patients comparable to recurrence rates described in the literature.

Published
2022

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