Biological Corrosion Resistance and Osteoblast Response of 316LVM Polished Using Electrolytic Plasma

As electrolytic plasma polishing (EPP) offers the advantages of strong shape adaptability, high efficiency, and environmental friendliness, it has great application prospects in biomedical material processing. However, the effect of EPP on the biological performance of the treated surfaces remains unclear. In the present study, the effects of EPP on the surface roughness, micro-morphology, corrosion behavior, and cell response of 316LVM were investigated. The results revealed that the surface roughness (Ra) was reduced from 0.3108 to 0.0454 µm upon EPP, and the sharp peaks and protrusions produced as a result of mechanical grinding were removed. The corrosion current density decreased from 1.129 to 0.164 µA/cm2, while the charge transfer resistance increased from 513.3 to 17,430 kΩ·cm2, which implied that EPP treatment could significantly improve the corrosion resistance of 316LVM. Furthermore, affected by the sharp ridges on both sides of the groove, the outward spreading of osteoblasts (MC3T3-E1) on the untreated samples was inhibited, and the edges were curled. The cells grew along the direction of the mechanical processing texture on the untreated samples, while they grew randomly in all directions on the surface treated using EPP, which adversely affected the growth, spreading, and migration of the cells.