Tailoring surface characteristics of laser powder bed fusioned AISI 316L stainless steel for biomedical applications

Abstract

AISI 316L stainless steel, manufactured using laser powder bed fusion (L-PBF) technology, is renowned for its low carbon content, biocompatibility, excellent mechanical properties, and corrosion resistance, making it suitable for biomedical applications. This research focuses on the vibro finishing and laser polishing of L-PBF AISI 316L stainless steel to improve its surface characteristics. The quality of the treatments was evaluated using various techniques, including X-ray diffraction, scanning electron microscopy, surface roughness analysis, electrochemical tests, wettability assessment, cytotoxicity analysis, and cell adhesion promotion assessment. The results indicate that both surface treatments effectively reduced surface roughness under optimal conditions. Laser-polishing treatment significantly improved wettability and demonstrated higher corrosion resistance during experiments conducted in phosphate-buffered saline. Electrochemical outcomes indicate that the vibro-finished and laser-polished samples possess superior corrosion resistance compared to the as-built L-PBF, which can be attributed to the improvement in surface properties. Moreover, the treated samples exhibited favorable surface energy, positively influencing cell adhesion. Furthermore, analysis of cell morphology reveals that when MG63 cells are cultured on laser-polished surfaces, they exhibit better adhesion compared to the as-built samples. These findings highlight the potential of vibro-finishing and laser-polishing techniques in enhancing the surface quality and biocompatibility of L-PBF AISI 316L stainless steel, offering promising prospects for its application in biomedical devices.