Preparation of PEG-coated surfaces and a study for their interaction with living cells

Cell-biomaterial interaction is of great importance for the development of bioinert as well as of hybrid surfaces. This study represents our results of human fibroblast interaction with PEG-coated surfaces of differing length and structure (linear or branched) of the oxyethylene chain. We employed three PEGs -- PEG 1500 and PEG 6000, both lineal but with different chain lengths, and PEG 12500 which was branched. The PEGs were deposited on silica plates using branched poly(ethylene imine) as an anchoring polymer. Fibroblasts were plated and studied by immunofluorescence to evaluate the overall cell morphology, the organisation of the actin cytoskeleton, and the beta1-integrin (fibronectin receptor). The particular effect of fibronectin (FN) pre-adsorption was studied. Our results suggest that PEG 6000 surface is to be preferable with respect to the initial interaction with the cells. The overall cell morphology was almost normal on bare surfaces. FN pre-coating additionally improved cell adhesion and spreading as well as the organization of the actin cytoskeleton and focal adhesion formation; the PEG 12500 surface showed relatively poor initial properties. Almost no cell spreading was found on the bare surface, but FN pre-adsorption completely restored normal cell morphology. In contrast, PEG 1500 had to be considered is 'the worst' material, because of lower initial cell adhesion and spreading and FN pre-adsorption did not restore normal cell morphology.