A New Method of Heparinizing PLLA Film by Surface Entrapment

A new method of surface heparinizing biodegradable polymers was designed. A heparin-modified poly(L-lactic acid) (PLLA) system was developed by physically entrapping the heparin on the PLLA surface. The surface characterization and biological performance of these materials were carried out by SEM, attenuated-total-reflection spectroscopy, contact angle measurements, and platelet adhesion evaluations. The modification strategy was performed by reversible swelling of the PLLA surface following exposure to a solvent–nonsolvent mixture. This process resulted in the localized physical entrapment of the diffused heparin. X-ray photoelectron spectroscopy was used to confirm that control over the heparin surface density can be achieved by using set polymer treatment times. Platelet adhesion tests showed significant improvement in blood compatibility by the PLLA surfaces after modification.