The response of fibrinogen, platelets, endothelial and smooth muscle cells to an electrochemically modified SS316LS surface: towards the enhanced biocompatibility of coronary stents.

Modification of a biomedical-grade stainless steel 316LS surface by electrochemical cyclic potentiodynamic passivation (CPP) and the response of fibrinogen (Fg), platelets, endothelial cells (ECs) and smooth muscles cells (SMCs) to this surface was investigated. Polarization modulation infrared reflection absorption spectroscopy revealed a significant difference between the secondary structure of Fg adsorbed on the unmodified and CPP surface, the latter being closer to that of native Fg. This was postulated as the origin of the significantly lower surface density of attached platelets on the CPP surface. The competitive interaction of ECs and SMCs with the surface showed that the ECs/SMCs surface density ratio is significantly higher on the CPP surface over the first 2h of attachment, suggesting faster initial attachment kinetics of ECs on the CPP surface. The presented results thus clearly demonstrate an increase in biocompatibility of the CPP 316LS surface.