Site-directed immobilization of antibodies onto blood contacting grafts for enhanced endothelial cell adhesion and proliferation

Abstract

Immobilization of antibodies, which exhibit high affinity towards the markers or receptors of endothelial cells (ECs) and circulating endothelial progenitor cells (EPCs), is proven to be an effective strategy to accelerate endothelialization and thereby lower the thrombosis of blood contacting grafts. Here, we have developed a new periodate-oxidized (PO) site-directed immobilization approach to better control the orientation of antibodies and retain their immunoactivity. In this PO site-directed route, the 316L stainless steel (316LSS) model substrate was first coated with ethylene vinylacetate and followed by oxygen plasma treatment and silane functionalization. Then the periodate-oxidized anti-CD34 model antibodies were immobilized. XPS measurements indicated the successful immobilization of the anti-CD34. The immobilized antibodies retained their bioactivity and exhibited better capturing efficiency (increase of about 3-fold compared with the conventional glutaraldehyde surface treatment) of specific antigens. Consequently, the endothelial cell attachment, after 4 h and 12 h cultivation, increased 93% and 116%, respectively. Cells grew better on these antibody-coated substrates with a quick confluent cycle (∼12 h). Further studies showed that this PO site-directed approach was able to reduce blood coagulation. Therefore, this PO site-directed route developed here is a promising strategy to immobilize antibodies with controlled orientation and higher bioactivity for rapid re-endothelialization of the cardiovascular implants.