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Surface modification of biomaterials.

Oberflächenmodifizierung von Biomaterialien
: Dörfel, J.; Müller, M.; Bauser, H.

4th European Symposium on Biomaterials
European Symposium on Biomaterials <4, 1991, Siena>
Fraunhofer IGB ()
biomaterial; FTIR attenuated total reflection; FTIR-Totalreflexionsspektrum; Oberflächenmodifizierung; Pfropfpolymer; polymer grafting; protein adsorption; Proteinadsorption; surface modification

It is well known that the interaction between a surface and blood components is greatly influenced by the chemical nature of the surface. In this study chemically homologous chain molecules were grafted onto polymer surfaces in order to investigate the influence of chain length on the adsorption of blood proteins. Polyethyleneglycol (PEG) molocules were used as the homologous series. After functionalizing of the hydroxyl end of PEG molecules, the chains were grafted onto polysiloxane surfaces. This, in effect, had the molecules fixed while leaving the methylated end dangling freely. This surface modification was applied to thin polysiloxane layers on top of a germanium infrared ATR element. The element was mounted in a flow cell and challenged successively with protein and buffer solutions. By means of FTIR-ATR spectra, adsorption and desorption of proteins have been measured as a function of time. In addition, radio labelled proteins have been used to detect protein adsorption on the modified surfaces. The amout of protein adsorbed decreased with increasing chain length of the PEG molecules grafted on the surface. The results are compared with the dependence of water contact angles on chain length. It is concluded that the effect on protein adsorption cannot solely be ascribed to the chemical nature of the functional groups, but also to the microstructural and/or dynamic pecularities of the modified surfaces.