Reduced platelet adhesion to titanium metal coated with apatite, albumin–apatite composite or laminin–apatite composite

Titanium metal coated with apatite (HA–Ti), albumin−apatite composite (AA–Ti) or laminin−apatite composite (LA–Ti) was prepared by the immersion of NaOH- and heat-treated titanium metal in a calcium phosphate solution, or one supplemented with albumin or laminin. Platelet adhesion to the obtained materials under flow conditions was investigated in real time using a cone- and plate-type viscometer and fluorescence labeled platelets. Adhesion and activation of the platelets on the HA–Ti, AA–Ti and LA–Ti were definitely suppressed as compared with those on untreated titanium metal with a mirror surface. Furthermore, the numbers of platelets adhered to AA−Ti and LA–Ti are smaller than those adhered to HA–Ti, although the differences were not statistically significant. These findings suggest that HA–Ti, AA–Ti and LA–Ti, especially AA–Ti and LA–Ti, would exhibit thromboresistance that is superior to commercially pure titanium metal in terms of platelet adhesion.