Zinc-based materials for the treatment of infectious bone defects: recent advances and perspectives

Infectious bone defects are simultaneously challenged by persistent infection, biofilm-mediated tolerance and impaired bone regeneration, so the conventional debridement-antibiotics-staged reconstruction strategy often fails to achieve infection control and defect repair in one course. Owing to their degradability, broad-spectrum antibacterial activity and the potential to modulate osteogenesis and immunity, zinc-based materials have been regarded as promising candidates for integrated therapy. Based on a systematic search and screening of recent literature, this review summarises four technical routes-pure zinc and zinc alloys, zinc-containing composite materials, zinc-based coatings and zinc-based delivery systems-and elucidates the antibacterial/anti-biofilm mechanisms of zinc together with its roles in osteogenesis, angiogenesis and immune regulation. On this basis, we propose several engineering design points for clinical translation, including suppression of burst release, regulation of micro-galvanic effects and second-phase distribution, coordinated optimisation of surface structure and surface chemistry, and standardised characterisation. We also discuss strategies for integrating zinc with current clinical materials (such as antibiotic-loaded bone cement and 3D-printed patient-specific scaffolds), as well as bottlenecks in large-scale manufacturing, long-term safety and the clinical evidence chain. In summary, zinc-based materials are expected to achieve a synergistic effect of infection control-promotion of bone repair-immune homeostasis, thereby providing a feasible materials-based solution and translational roadmap for infectious bone defects.