Expansion and optimization of mesenchymal stem cells (MSCs) cultivation
The use of MSCs is promising for cell therapy and tissue engineering. MSCs, isolated from a variety of tissues, are already used in numerous clinical trials. Furthermore, the use of MSCs is less restricted by administrative requirements than the use of embryonic and induced pluripotent stem cells.
Since therapeutic applications typically require several million MSCs per patient, it is necessary to develop optimized culture protocols for in vitro cell expansion. In our projects we use MSCs which are obtained from adipose tissue in cooperation with the Department of Plastic and Reconstructive Surgery of the Hannover Medical School (MHH). Together with the Department of Research and Development of the German Red Cross, platelet lysates are evaluated as supplements for in vitro MSC cultivation and compared with traditional protocols (with FCS and human serum).
3D cell culture systems and bioprinting
In addition, various 3D cell culture systems are applied and evaluated for the cultivation of MSCs and other cell types: cell aggregates (or microtissues), natural and synthetic scaffolds, and hydrogels. To enable complex in vitro 3D systems, various hydrogels (e.g. alginates, PEG-fibrinogen and GelMA) are tested as Bioinks for 3D bioprinting. Hydrogels biocompatibility degradation, printability and mechanical properties are studied in collaboration with "Biomaterials for regenerative therapy". Bioprinting helps not only to produce artificial tissue engineering constructs, but also to create physiologically relevant in vitro 3D models for drug screening.
As part of the DFG-funded project 398007461 "3D Two Gradient Systems for Functional Cell Testing", we are developing hydrogel-based in vitro gradients. The aim of the present research project is the development of a 3D cell culture system where multiple-gradient hydrogels can be created in order to obtain complex, but precisely defined in vitro microenvironments. Through variation of the hydrogel composition, mechanical gradients can be realized in the culture model, which allow a systematic investigation of the influence of microenvironmental conditions. Orthogonally, an oxygen concentration gradient is established, so that combinations of hydrogel composition and different oxygen concentrations can be tested within one experiment. With the help of this novel test system, it should be possible to quickly and reliably determine the combined influence of various factors on cell behavior, in order to find optimal culture conditions for specific applications.