Preparation of heparin containing SBS-g-VP copolymer membrane for biomaterial usage

Vinyl pyridine (VP) was grafted onto styrene-butadiene-styrene (SBS) triblock copolymer membrane by UV-radiation induced graft copolymerization without degassing to obtain the SBS-g-VP copolymer membrane. The substituted pyridine groups on the SBS-g-VP graft copolymer membrane were quaternized with iodomethane, and then the membrane was treated with heparin to prepare the heparin containing SBS-g-VP copolymer membrane (SBS-g-VP-HEP). The SBS-g-VP and SBS-g-VP-HEP were characterized by electron spectroscopy for chemical analysis (ESCA). The heparin content was determined by toluidine blue heparin assay. The contact angles of dry and wet SBS-g-VP and SBS-g-VP-HEP with different amount of grafting and heparin content were determined. By using Kaelble's equation, the surface energies of SBS-g-VP and SBS-g-VP-HEP were determined. It was found that the surface energy and water content of SBS-g-VP and SBS-g-VP-HEP membrane increased with increasing graft amount and the heparin content, whereas the contact angle decreased. Protein adsorption of fibrinogen and albumin onto the membranes was also performed to evaluate the effect of graft amount and heparin content on the biocompatibility of SBS-g-VP and SBS-g-VP-HEP membranes. The amount of the adsorption of albumin and fibrinogen decreased with increasing grafting amount and heparin content. Copyright © 1998 Published by Elsevier B.V.