Protein adsorption and cell attachment to patterned surfaces

To better understand the events involved in the generation of defined tissu e architectures on biomaterials, we have examined the mechanism of attachme nt of human bone-derived cells (HBDC) to surfaces with patterned surface ch emistry in vitro. Photolithography was used to generate alternating domains of N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS) and dimethyldichl orosilane (DMS). At 90 min after seeding, HBDC were localized preferentiall y to the EDS regions of the pattern. Using sera specifically depleted of ad hesive glycoproteins, this spatial organization was found to be mediated by adsorption of vitronectin (Vn) from serum onto the EDS domains. In contras t, fibronectin (Fn) was unable to adsorb in the face of competition from ot her serum components. These results were confirmed by immunostaining, which also revealed that both Vn and Fn were able to adsorb to EDS and DMS regio ns when coated from pure solution, i.e., in the absence of competition. in this situation, each protein was able to mediate cell adhesion across a ran ge of surface densities. Cell spreading was constrained on the EDS domains, as indicated by cell morphology and the lack of integrin receptor clusteri ng and focal adhesion formation. This spatial constraint may have implicati ons for the subsequent expression of differentiated function. (C) 2000 John Wiley & Sons, Inc.