Composite dip coating improves biocompatibility of porous metallic scaffolds

Porous materials are becoming more common for bone implants, and it is increasingly important to find surface modification strategies that affect both the implant exterior and porous interior. In this study, selective laser melting (SLM) was used to create porous stainless steel implants 8 mm in diameter, which were subsequently dip coated with a composite polymethylmethacrylate-alumina (PMMA-Al2O3) film. Imaging with electron microscopy found evidence of the films at a depth of 2.2 mm into the porous implants, with dual-scale topography created by the native SLM stainless steel substrate and alumina nanoparticles. Energy dispersive X-ray spectroscopy confirmed the presence of the coating along the periphery of interior pores. In vitro tests with osteoblast-like cells showed greater cell metabolism on composite-coated samples compared to uncoated dense samples after seven days of culture.