Bioinspired cell membrane-like hybrid coating for enhanced bioactivity and corrosion resistance of magnesium-based implants

Magnesium (Mg)-based biometals are promising candidates for next-generation biodegradable implants in bone regeneration. However, their rapid biocorrosion in physiological environments necessitates protective coatings to enhance corrosion resistance and osteogenesis. Conventional hydrophobic modifications, while effective in mitigating corrosion, often impair biological responses, hindering tissue integration and bone regeneration. Inspired by the architecture of cell membranes, we developed a novel layered octacalcium phosphate (OCP) coating intercalated with a hydrophobic alkyl-phosphate-surfactant bilayer, imparting Mg biometals with enhanced bioactivity and resistance to biocorrosion. Additionally, an MgF₂ transition layer with a mechanically interlocking architecture is fabricated via an in situ growth approach, ensuring the long-term structural integrity and interface stability of the hybrid coating. Compared with conventional coatings, the resulting intercalated organic/inorganic hybrid coatings exhibit exceptional mechanical robustness, remarkable corrosion resistance, and bioactivities conducive to cellular adhesion and proliferation. In vivo implantation tests further revealed a significantly reduced corrosion depth (~ 1.1 μm), minimal inflammatory response, and reduced fibrous encapsulation (~ 65.2 μm), demonstrating its clinical potential. This work pioneers a bioinspired strategy for multifunctional inorganic/organic hybrid coatings, advancing the clinical application of Mg-based implants in osteogenesis.

Graphical abstract