Fabrication and characterization of nanostructure on 316L stainless steel via anodization

316L stainless steel is most commonly used biomaterials for cardiovascular stents. Despite its widespread use in clinics, bare stainless steel stents experience problems after implantation i.e. such as nickel ion release, corrosion and limited endothelial cell coverage due to its bioinert nature1. One way to overcome these challenges is to modify the surfaces of 316L stainless steel stents to possess nanofeatures, which can potentially limit nickel ion release and corrosion, while improving bioactivity of stainless steel2. In this study, nanostructures ranging from 25 nm to 250 nm in diameter were fabricated on 316L stainless steel via anodization. AFM root mean square roughness (rms) value for the unanodized sample was found to be 7.5 nm, while for anodized samples it was, 2.4 nm. Chemical analysis of the surfaces by XPS showed that anodized surfaces mainly composed of Fe2O3 and Cr (III) oxide. Also, the hydrophobicity of different surfaces was investigated by water contact angle analysis. In addition, the unanodized stainless steel had a contact angle of 57°, while anodized stainless steel with 30 nm diameter and anodized stainless steel with 150 nm diameters had contact angles of 96° and 98°, respectively. Importantly, in vitro testes showed that anodized stainless steel surfaces dramatically enhanced proliferation of osteoblast cells compared to control surface, which suggest its potential use as a biomaterial for vascular applications