Fast and efficient screening system for new biomaterials in tissue engineering: a model for peripheral nerve regeneration Stephanie Bruns, 1 Yvonne Stark, 1 Martin Wieland, 2 Frank Stahl, 1 Cornelia Kasper, 1 Thomas Scheper 1 1 Institute for Technical Chemistry, University of Hannover, Callinstr. 3, D-30167 Hannover, Germany 2 Dr. Suwelack Skin & Health Care AG, Josef-Suwelack-Straße, D-48727 Billerbeck, Germany Received 10 March 2006; revised 19 July 2006; accepted 19 September 2006 Published online 16 January 2007 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jbm.a.31120 Abstract: The use of three-dimensional biodegradable ma- trices is one major issue in tissue engineering. Numerous materials, fabrication techniques, and modifications have been used and tested in different areas of tissue engineering recently. But nevertheless, technology is far from being opti- mized and optimal constructs with bioidentical and me- chanical properties have not been described in the literature so far. Hence, there is great demand of new suitable bioma- terials for tissue engineering applications. In this study, a fast and efficient screening system for initial testing of bio- materials for cell culture application was developed. The set up for the screening system and the decision criteria applied for the determination of suitability of new materials are presented. Hep-G2 and PC-12 cells were seeded onto different matrices and cultured over a period of 2 weeks. The viability of the cells was monitored via the MTT assay. Cell spreading was investigated by DAPI-staining of cell nuclei. Furthermore, the adhesion of the cells on the differ- ent matrices was examined by counting the number of attached cells. With these general assays a classification of materials is possible with regard to their suitability. Opti- mal cell models must be chosen for the defined applications and at least two cell lines are necessary for a differentiating interpretation. Ó 2007 Wiley Periodicals, Inc. J Biomed Mater Res 81A: 736–747, 2007 Key words: biomaterial; biocompatibility testing; screen- ing; tissue engineering; peripheral nerve regeneration INTRODUCTION The rapidly growing knowledge and technical com- petence in the field of transplantation medicine is accompanied by an urgent lack in organ availability and this gap will continuously broaden. A new inter- disciplinary, young, and emerging scientific area ‘‘tissue engineering’’ was generated over the last few years, which promises to change medical practice profoundly. It will contribute the regeneration of the diseased tissues and organs instead of just repairing them. The tissue generation by autologous cell trans- plantation is one of the most promising treatment concepts being developed as it eliminates problems of donor site scarcity, immune rejection, and risk of infection. 1 The in vivo development of organs and tissues essentially depends on the ability of cells to grow in a three-dimensional system that provides the tissue- specific information and shape, cell–cell communica- tion and interaction with the surrounding tissue. Unfortunately, cells in monolayer culture have lost the ability to orientate in three dimensions and thus have lost the ability to reconstruct the anatomical structure of the organ on their own. This problem is approached by the use of highly porous and artificial matrices on which cells attach and proliferate. Such biomaterials replace the task of the extracellular ma- trix (ECM), which naturally provides cells with a sup- portive framework of structural proteins, carbohy- drates, and signaling molecules. 2 Beyond the mimicry of ECM characteristics, the ideal scaffold should form a structure with similar physical properties and shape as the desired tissue. Furthermore, suitable matrices should support cell attachment, proliferation, and dif- ferentiation toward the desired phenotype. They have to be biocompatible and simultaneously biodegrad- able whereas the rate of degradation should not be too fast. Degradation rate and production rate of new ECM should rather be balanced in order to release an autonomous organ. 3 Numerous materials have been used and tested as scaffold materials in different tissue engineering fields until today. Particularly on the intensely re- searched field of bone and cartilage tissue engineer- Correspondence to: T. Scheper; e-mail: scheper@iftc. uni-hannover.de ' 2007 Wiley Periodicals, Inc.