Interaction of cells on the surface of multiphase polymer assemblies

Abstract

Summary—The long-term, in vivo antithrombogenicity of heparinized polyetherurethaneureas suggested that the promotion of endothelialization of synthetic materials by controlling surface properties is promising for the development of truly biocompatible materials. To estimate properties of synthetic materials for in vivo pseudo-endothelialization, interactions of polyetherurethaneurea derivatives with fibroblast cells as well as with plasma proteins were investigated. Fibronectin, which is a cell adhesion protein, was easily adsorbed by the heparinized polyetherurethaneurea, but the degree of adsorption to the polymer in competition with other proteins was so low that the cell attachment to polyetherurethaneurea was decreased by heparinization. Different degrees of cell attachment onto different materials were considered due to different extents of adsorption of plasma proteins. Proliferation of fibroblast cells was suppressed on cationic polyetherurethaneureas but unaffected on other derivatives of polyetherurethaneureas. The absence of specific suppression of cell growth indicates the usefulness of heparinized polyether-urethaneureas for truly biocompatible materials by pseudo-endothelialization. Attachment and growth of fibroblast cells on polypeptide derivatives with different wettabilities were also studied in the presence or absence of serum proteins. In the presence of serum, a peak level of cell attachment was observed for substrates with a contact angle of around 70°. However, no relationship was found between cell attachment and water contact angles of substrate polymers in the absence of serum. Ca2+-dependent cell attachment was observed on hydrophobic surfaces in the absence of serum proteins, suggesting that Ca2+-dependent membrane proteins function as mediator during attachment to hydrophobic surfaces. In the presence of serum proteins, it was found that cell attachment is affected by metabolism, Ca2+ and the cytoskeleton of the cell. Cell growth rate on hydrophilic substrates was higher than on intermediate or hydrophobic substrates, demonstrating that strong interactions between cells and substrates are unfavorable for a dewebbing process during mitosis.