Laser powder bed fusion of biodegradable metallic implants: current status, challenges, and future perspectives

Biodegradable metals (BMs), encompassing magnesium (Mg)-, zinc (Zn)-, and iron (Fe)-based alloys, represent a revolutionary advancement in biomedical implants. Among them, Mg-based alloys are distinguished by their bone-mimetic elastic modulus, which helps mitigate stress shielding, and their bioactive Mg 2+ ions that promote osteogenesis. Zn-based alloys provide an intermediate degradation rate, avoiding the rapid corrosion of Mg and the prolonged presence of Fe, while Fe-based alloys are valued for their superior mechanical strength, making them suitable for load-bearing applications. These materials eliminate the need for secondary removal surgeries, minimize stress shielding, and support tissue regeneration. However, conventional manufacturing methods struggle to produce patient-specific implants with complex geometries. Additive manufacturing (AM), particularly laser powder bed fusion (LPBF), enables the fabrication of customized, porous implants with high dimensional accuracy and refined microstructures. The rapid cooling inherent to LPBF enhances mechanical strength, corrosion resistance, and degradation control. Nevertheless, key challenges remain, such as optimizing process parameters to minimize defects, ensuring consistent degradation behavior, and matching mechanical performance with tissue healing timelines. This review systematically outlines recent advances in the AM-fabricated BMs, covering material development, powder preparation, parameter optimization, post-processing, and defect mitigation. It critically assesses their mechanical properties, degradation behavior, and biocompatibility. Finally, the review highlights persistent challenges and suggests future research directions to advance clinical applications. • A review of the necessity and progress in LPBF of BMs is presented. • Summary of advances from material development to defect mitigation is provided. • Assessment of properties and preclinical applicability is included. • Outline of future challenges and research directions is offered.