Chitosan-heparin nanoparticle coating on anodized NiTi for improvement of blood compatibility and biocompatibility.

The aim of this study was to simultaneously improve blood compatibility and corrosion resistance of nitinol via two-step process; anodizing and consequently coating with chitosans-heparin nanoparticles. Moreover, the role of these surface modification processes on the heparin release kinetic and blood compatibility was investigated. Finally, the interaction between human umbilical vein endothelial cells (HUVECs) and surface modified samples was investigated. Electrochemical characterization revealed that while Ni ions released from the anodized sample (9 ppb), chitosan-heparin nanoparticle coatings prohibited from Ni ion release form NiTi substrate. Moreover, the controlled release of heparin was found from chitosan-heparin nanoparticle coating deposited on the nanotubes, leading to significant improvement of blood compatibility. Finally, HUVECs were attached and proliferated on the chitosan-heparin nanoparticle coated samples confirming the cell compatibility of samples. In summary, results proved that two-step anodizing process and heparin release could promote both endothelial cell compatibility and blood compatibility to nitinol surface which might be appropriate for coronary stent application.