[Serum-free cultivation of osteoprogenitor cells and osteoblasts to test biomaterials].

The aim of the study is to describe a model for testing biocompatibility of implant materials. Usually cells do not bind the biomaterial surface itself via integrins but adsorbed proteins of blood or interstitial fluids. To eliminate the influence of serum proteins on cell adhesion to the test materials we cultivated osteoprogenitor cells and osteoblasts with a serum replacement or with fetal calf serum, but seeded them likewise without serum or serum replacement on cell culture polystyrene, sandblasted titanium and titanium coated with the peptide c(RGDfK) or hydroxyapatite (Bonemaster) and determined cell adhesion. In addition, the surfaces were preincubated with the serum proteins albumin, fetuin, fibronectin and vitronectin to examine specifically their influence on cell adhesion. Clearly cell adhesion depended on cell culture conditions and state of differentiation, especially with prominent differences in adhesion to c(RGDfK). Precoating with serum proteins demonstrated that besides fibronectin and vitronectin fetuin can function as an adhesion protein, whereas albumin demonstrated an antiadhesive effect. Depending on the material they affected cell adhesion differently. Although osteoprogenitor cells and osteoblasts could bind to tissue culture polystyrene, titanium and especially hydroxyapatite without mediation of proteins, it has to be taken into consideration that cell spreading and proliferation of cells on a scaffold are more important than adhesion alone and may not be ensured in the absence of adhesion proteins.