We report this modification of poly (lactic-coglycolic acid) (PLGA) scaffolds,both to impart hemocompatibility to prevent platelet adhesion and aggregation before the endothelial confluence is fully achieved,and to support EC growth to accelerate endothelialization.The modification was achieved by covalent immobilization of sulfated silk fibroin on PLGA scaffolds using gamma irradiation.The systematic in vitro hemocompatibility evaluation revealed that sulfated silk fibroin covalently immobilized PLGA (S-PLGA) scaffolds reduced platelet adhesion and activation,prolonged whole blood clotting time,activated partial thromboplastin time (APTT),thrombin time (TT),and prothrombin time (PT).Vascular ECs were seeded on the scaffolds and cultured for 2 weeks.The ECs were seen to attach and proliferate well on S-PLGA scaffolds,forming cell aggregates that gradually increased in size and fused with adjacent cell aggregates to form a monolayer covering the scaffold surface.Moreover,it was demonstrated through the gene transcript levels and the protein expressions of EC-specific markers that the cell functions of ECs on S-PLGA scaffolds were better preserved than those on PLGA scaffolds.