Preparation of Topographically Modified Poly(L-lactic acid)-b-Poly(epsilon-caprolactone)-b-Poly(L-lactic acid) Tri-Block Copolymer Film Surfaces and Its Blood Compatibility

Abstract

Hindering early platelet adhesion and enhancing human vascular endothelial cell proliferation on surfaces of the foreign materials play a key role in the prevention of coagulation. In order to develop topographically suitable surface for artificial grafts, topographically modified poly(L-lactic acid)-b-poly(epsilon-caprolactone)-b-poly(L-lactic acid) tri-block copolymer (PLLA-PCL-PLLA) film surfaces were cast using a simple solvent-nonsolvent method. PLLA-PCL-PLLA copolymer was synthesized, and was confirmed by H-1 nuclear magnetic resonance (NMR) analysis. The molecular weight of the copolymer was measured using gel permeation chromatography (GPC). PLLA-PCL-PLLA films were cast with various ratios of non-solvent in the solvent mixture. Tetrahydrofuran (THF) and ethyl alcohol (EtOH) were used as solvent and nonsolvent respectively. The hydrophobic characteristic of the surfaces was confirmed by the water contact angle (WCA). The prepared film surfaces were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). Anti-platelet adhesion characteristic was evaluated using Lactate Dehydrogenase (LDH) assay and SEM images. Proliferation behavior of human vascular endothelial cell was investigated by water-soluble tatrazolium salt (WST) assay after 3 h, 1 day, 2 days and 4 days of cell culture on the film surface. Fabricated morphologically unique surface, which consists of submicron size width and nano size height rough structure, shows anti platelet adhesive ability and relatively higher human vascular endothelial cell proliferation behavior.