In vitro short-term platelet adhesion on various metals

The in vitro short-term platelet adhesion oil various metals, as accelerated by the addition of Ca2+, was evaluated in this study. Metals used for medical devices [ail austenitic stainless steel, a cobalt (Co)-chromium (Cr)-molybdenum (Mo) alloy, a titanium (Ti)-6 aluminum (Al)-4 vanadium (V) alloy, a Ti-6Al-7 niobium (Nb) alloy, a Ti-nickel (Ni) alloy, and commercially pure Ti] were immersed into a platelet-rich plasma Solution for 5 or 20 min, and platelet adhesion and aggregation on the Surfaces were observed using a scanning electron microscope. The platelet adhesion level oil each metal after 5 min of immersion in it platelet-rich plasma solution was the smallest in this order: stainless steel <= Co-Cr-Mo alloy < Ti-6Al-4V alloy < Ti-6Al-7Nb alloy < Ti-Ni alloy = Ti. The levels after 5 min of immersion were almost the same as those after 20 min of immersion. Platelet adhesion was minimal oil stainless steel and Co-Cr-Mo alloy, which have it Cr2O3-containing passive surface oxide film, but was accelerated oil Ti and Ti alloys having a TiO2-contanining film. A Cr2O3-containing oxide film has a lower relative permittivity than a TiO2-contanining film, it thus supports a larger electrostatic force than the latter, adsorbs more albumins, which work as inhibitory proteins, and inhibits platelet aggregation. Therefore, platelet adhesion and aggregation are controlled by the composition of the surface oxide film oil a metal due to the relative permittivity of the metal, which influences the amount of adsorbed proteins.