Fachgruppe Nanostrukturierte Materialien    

Intrinsic cross-linking is not only useful for increasing stability, but also for tailoring mechanical properties of polyelectrolyte multilayers (PEM) on implants and tissue engineering scaffolds. Here, a novel route for synthesizing thiolated chitosan (t-Chi) based on the application of 3,3?-dithiodipropionic acid was applied, while thiolated chondroitin sulfate (t-CS) was conjugated by 3,3?-dithiobis (propanoic hydrazide). Both products were subsequently reduced to obtain the free thiols. The thiol content, structural changes and degree of substitution were studied by UV–vis, FTIR, Raman and 1H NMR spectroscopy, respectively. Chi and CS can be used for PEM formation with the layer-by-layer method, due to the cationic nature of Chi at pH values below 5.0 and the anionic character of CS. Comparative studies on the formation of native Chi/CS versus t-Chi/t-CS PEM with surface plasmon resonance and ellipsometry revealed higher layer mass. We also found that the PEM composed of t-Chi/t-CS had superior cell adhesion properties for human keratinocytes in comparison to the native PEM.