SLM-Ti/hydrogel composite scaffold with spatiotemporal release of functional drugs for enhanced bone regeneration

The application of Selective Laser Melting (SLM) porous titanium scaffolds for patient-specific implants is steadily expanding; however, enhancing their bioactivity to support effective bone repair remains a significant challenge. This study presents a novel composite scaffold designed to enable spatiotemporally controlled release of dexamethasone (Dex) and bone morphogenetic protein-2 (BMP-2), thereby promoting bone regeneration and establishing a pro-healing microenvironment in bone defects. The composite scaffold integrates an outer SLM-Ti framework coated with a Dex-loaded polypyrrole (PPy) film for on-demand release, and an inner OSA-Gel (OG) hydrogel loaded with BMP-2-encapsulated mesoporous bioactive glass nanoparticles (MBGNs) for sustained delivery. The results demonstrate that the controlled dual delivery of BMP-2 and Dex exerts a significant synergistic effect in promoting cellular proliferation and osteogenic differentiation in vitro. These findings provide a theoretical basis for advancing SLM-Ti customized implants toward preclinical application in bone regeneration.