Significantly enhanced biocompatibility and performance of 3D-printed porous 316L stainless steel via a simple and efficient surface polishing approach

Abstract

• High-voltage AO effectively removes residual powder from 3D printed porous 316L implants. • Porous 316L stainless steel matches natural bone elasticity and compressive strength. • AO polishing retains strength while improving impact-buffering capability and energy absorption. • Ripple-like textures produced by AO polishing significantly enhance biocompatibility. • Reduced failure risk and bioactive surfaces promote advanced use in bone implants. Residual powder on the surface and within the pores of Gyroid-structured porous 316L stainless steel implants fabricated via powder bed fusion-laser beam (PBF-LB) impairs biocompatibility and increases implant failure risk. This study introduces a reverse high-voltage anodic oxidation (AO) technique to address this issue effectively. By leveraging high-voltage AO, non-ordered, large-diameter, deep, and weakly bonded honeycomb structures are generated, facilitating the removal of residual powder. Subsequently, low-frequency ultrasound is applied to further disrupt these structures for deeper powder removal and the creation of stable micro-nanoscale surface patterns. Mechanical testing revealed that polished 316L-AU-50 samples maintained compressive properties, exhibiting higher plateau stress and energy absorption, which provided superior bone protection. Moreover, These modifications significantly enhance bioactivity by creating ripple-like, fish-scale, and dendritic textures on the pore walls, which promote cell adhesion, proliferation, and differentiation. This study demonstrates that reverse high-voltage AO, combined with ultrasonic disruption, is a promising approach for removing residual powder, preserving mechanical integrity, and enhancing bioactivity, offering significant potential for clinical applications of porous 316L stainless steel implants.

Topics & Concepts