Immobilization of a biologically active coating on a hydrophobic L-lactide-epsilon-caprolactone copolymer

The electron beam radiation induced grafting method was used to attach a reactive polyacrylamide (PAA) layer (20 wt %) on the surface of a biodegradable poly-L-lactide-co-epsilon-caprolactone (PLLA-co-CL). The biocompatibility of graft-polymer obtained was studied by cytotoxicity test and no signs of toxicity were observed. Heparin and sol-gel-produced silica-gel coatings were successfully attached on the top of the polymeric material produced. The amount of heparin immobilized directly on the surface can be controlled by reaction conditions: reaction time, temperature and pH of the incubation solution. By using acidic conditions, up to 98 microg cm(-2) of heparin was immobilized on the surface. The sol-gel-produced silica-gel layer formed by dipping technique was 30 microm thick and the cracking of the layer was minimal after bending several times to 90 degrees.