With the development of a wide range of new biomaterials for the sensing of different cell behaviour, it is important to consider whether the cells tested in vitro are in direct contact with the material or whether cell-biomaterial contact is mediated by an interfacial layer of proteins originating from the culture medium or from the cells themselves. Thus, this study describes the differences between the cell adhesion mediated by proteins originating from foetal bovine serum and without the presence of such proteins 2 h following cell seeding exemplarily with different cell types (an osteoblastic cell line, primary fibroblasts, and mesenchymal stem cells). Three of the examined cell types were found to react differently to differing conditions in terms of cell shape, area, and number. Nevertheless, the expression and localization of the various proteins involved in cell adhesion and signalling (CD44, vinculin, talin, actin, focal adhesion kinase, Rho-GTPases and extracellular signal-regulated kinases 1 and 2) were, in general, similar with respect to all the cell types tested, albeit varying according to the presence or absence of serum. Moreover, no classical focal adhesions were formed during cell adhesion without serum proteins, while different signalling pathways were involved in this process. The study systematically describes and discusses the cell adhesion of three different human cell types to a well-known substrate without the presence of external proteins and it is hoped that this knowledge will be subsequently applied in biomaterial applications in which the presence of external proteins is undesirable (e.g. for biosensing purposes).

Institute of Inherited Metabolic Disorders 1st Faculty of Medicine Charles University Prague Ke Karlovu 2 128 08 Prague 2 Czech Republic Biomedical Center Faculty of Medicine in Pilsen Charles University Prague alej Svobody 1655 76 323 00 Pilsen Czech Republic

Institute of Inherited Metabolic Disorders 1st Faculty of Medicine Charles University Prague Ke Karlovu 2 128 08 Prague 2 Czech Republic Department of Genetics and Microbiology Faculty of Science Charles University Prague Albertov 6 128 43 Prague 2 Czech Republic

Institute of Physiological Chemistry Faculty of Medicine Carl Gustav Carus Technical University Dresden Fiedlerstraße 42 01307 Dresden Germany

References provided by Crossref.org