Hemocompatibility improvement of perfusion-decellularized clinical-scale liver scaffold through heparin immobilization

Whole-liver perfusion-decellularization is an attractive scaffold-preparation technique for producing clinical transplantable liver tissue. However, the scaffold's poor hemocompatibility poses a major obstacle. This study was intended to improve the hemocompatibility of perfusion-decellularized porcine liver scaffold via immobilization of heparin. Heparin was immobilized on decellularized liver scaffolds (DLSs) by electrostatic binding using a layer-by-layer self-assembly technique (/h-LBL scaffold), covalent binding via multi-point attachment (/h-MPA scaffold), or end-point attachment (/h-EPA scaffold). The effect of heparinization on anticoagulant ability and cytocompatibility were investigated. The result of heparin content and release tests revealed EPA technique performed higher efficiency of heparin immobilization than other two methods. Then, systematic in vitro investigation of prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT), platelet adhesion and human platelet factor 4 (PF4, indicates platelet activation) confirmed the heparinized scaffolds, especially the /h-EPA counterparts, exhibited ultralow blood component activations and excellent hemocompatibility. Furthermore, heparin treatments prevented thrombosis successfully in DLSs with blood perfusion after implanted in vivo. Meanwhile, after heparin processes, both primary hepatocyte and endothelial cell viability were also well-maintained, which indicated that heparin treatments with improved biocompatibility might extend to various hemoperfusable whole-organ scaffolds' preparation.