EPD-derived SiO2 coatings on NiTi alloys: Biocompatibility and corrosion challenges in cardiovascular applications

NiTi shape memory alloys are a popular choice for cardiovascular implants due to their unique mechanical properties and good biocompatibility. However, their high nickel content poses a challenge by reducing their biocompatibility. To address this, surface modification methods are increasingly being explored. This study focused on applying a silicon dioxide (SiO 2 ) coating using electrophoretic deposition (EPD) to improve corrosion resistance and hemocompatibility. The EPD process was optimized for stable SiO 2 particle deposition, resulting in a porous, partially nanocrystalline, and amorphous coating. Physicochemical analyses revealed surface discontinuities that affected coating uniformity. Corrosion tests highlighted the coating’s vulnerability to transpassive corrosion, raising concerns about its long-term durability in oxidative environments. Biological evaluation showed promising cytocompatibility, with a vinculin-to-adhesion molecule ratio of 4:6 supporting strong cell adhesion. These findings underscore the potential of SiO 2 coatings for biomedical applications, while pointing to the need for further improvements to enhance long-term stability and performance in physiological conditions. • SiO 2 coatings were successfully deposited on NiTi alloys using EPD • Coated surfaces exhibited a porous, nanocrystalline, and amorphous structure • EPD increased hydrophilicity and surface free energy compared to bare NiTi • Corrosion tests revealed susceptibility to corrosion despite applied coating • Biological tests confirmed strong cell adhesion and promising cytocompatibility