Chirality-mediated enhancement of nitric oxide release and regulation of endothelial cells behaviors by cystine immobilization on Ti–O films

Endogenous nitric oxide (NO), generated by endothelial cells (ECs), plays a critical role in the cardiovascular system. However, the effect of biomaterial-induced NO release on ECs is not clear. In this study, cystine with different chirality was immobilized on Ti–O films to catalyze endogenous S-nitrosothiol decomposition to generate NO. Chemiluminescence analysis showed that a stable, sustained release of NO at a speed similar to that in healthy ECs was achieved on both enantiomer immobilized surfaces. However, L-cystine-immobilized surfaces induced higher NO release than D-cystine-immobilized surfaces. Although BSA adsorption was enhanced on L-surfaces, according to QCM analysis, preadsorption of BSA on L-surface still had a significantly higher NO release than that on the D-surface, indicating that the adsorption of BSA on L-surfaces was reversible. Platelet activation on the L-surfaces was obviously inhibited because of induction of more NO release. The growth, migration, and NO secretion behaviors of ECs were promoted by increased NO release on the L-surfaces. These results show that L-cystine-immobilized surfaces are beneficial for the induction of NO release and regulation of the behaviors of ECs, providing a promising method for the endothelialization of vascular biomaterials.