Heparin-Ornamented Polycaprolactone-Silk Fibroin Emulsion-Based Nano-/Microfibrous Conduit as a Promising Hemocompatible Tubular Graft.

The essential prerequisite of a vascular conduit is to provide a conducive, healthy lumen interface to the flowing blood within it. The persistent problem of late thrombosis, coagulation cascade activation, and vessel occlusion is pertinent in commercial and small-diameter vascular grafts (SDVG) (<6 mm diameter), upon coming in contact with blood flow. The above critical issues are overcome by providing an anticoagulant and antithrombotic coating to the lumen surface. This study explored the grafting of heparin on the polycaprolactone (PCL)-silk fibroin (SF) composite fabricated as emulsion electrospun core-shell fibers, followed by O2 plasma modification and silanization with 3-(aminopropyl) triethoxysilane (APTES). The density of heparin on PSH5 surfaces was ∼18.43 µg/cm2, sufficiently higher than in previous studies. Heparin-grafted fibers (PSH3 and PSH5) exhibited exceptional hemocompatibility with hemolysis % of (∼0.2 ± 0.003), maintaining a platelet discoid shape (∼3.5-3.9 µm diameter) without platelet activation/aggregation and conserving disc-shaped RBC morphology without apoptosis (∼5.6-5.8 µm diameter). PSH5 fibers further supported human umbilical vein endothelial cell (HUVEC) growth and proliferation on their surfaces with % cell viability of 121.8% after 5 days, with observation of the CD31 + HUVEC confluent monolayer in in vitro studies for 12 days. Subcutaneous in vivo implantation of PSH5 also depicted sufficient muscular layers and collagen deposition after 60 days of implantation with neovasculatures.