“…Heparin with the density of 2.6 mg/cm 2 on PU surface was found to significantly inhibit platelets adhesion [28], thus in our study, after PBS immersion for five days, the residual heparin was still enough to exhibit the anticoagulant properties. However, the amount of physisorbed heparin on Ti surface dramatically decreased to an extremely low level even at the 1st day, which was equivalent to that on TiOHA surface without heparin adsorption, and further decreased to a level equivalent to Ti BLK (blank sample), indicating a through loss of heparin on physisorbed Ti surface.…”