THE EFFECT OF PASSIVATION ON THE HAEMOCOMPATIBILITY OF 316L STAINLESS STEEL

The difference of haemocompatibility of medical 316L stainless steel passivated by nitric acid(NT) and citric acid(CT) was studied.Platelet adhesion and protein adsorption were studied to evaluate the haemocompatibility of the 316L stainless steel passivated by the two different methods.XPS analysis,water contact angle and surface charge measurement were used to analyze the surface properties of the steel such as chemical composition and depth distribution of the main elements in passivated films,surface energy and surface charge.The results showed that the 316L steel passivated by citric acid displayed better haemocompatibility,which could be related to the higher surface energy and relatively lower surface charge.The results also showed that the polar component of surface energy was of linear relation with the albumin adsorption on 316L stainless steel while the surface charge had the same relation with fibrinogen adsorption.