The Mo-14Re alloy, a promising candidate material for bioresorbable vascular scaffolds.

Abstract

Zinc‑, iron‑, and magnesium‑based biodegradable metals suffer inherent limitations as bioresorbable scaffold materials, including inappropriate degradation rates and insufficient mechanical strength. Pure molybdenum (Mo) has been proposed as an alternative, but its clinical application is hampered by brittleness and potential nephrotoxicity. A Mo alloy was engineered to address these challenges. By alloying with rhenium (Re), Mo-14Re sheets and microwires with tunable mechanical properties were produced, achieving enhanced ductility in Mo‑based materials while retaining adequate strength for vascular stent applications. Importantly, Re addition not only enhances plasticity but also markedly reduces the degradation rate of Mo and diminishes Mo accumulation in biodegradation residues, thereby mitigating renal toxicity-a significant advancement for Mo‑based implants. The Mo-14Re alloy demonstrates biocompatibility and antimicrobial activity, and 12‑week in vivo tests confirmed complete endothelialization of Mo-14Re wires implanted in rat abdominal aortae. Whereas pure Mo induced severe glomerulosclerosis, Mo-14Re exhibited no detectable nephrotoxicity, effectively addressing the principal safety concern of Mo implants. These findings open new directions for the development of high‑performance biodegradable metals. STATEMENT OF SIGNIFICANCE: This study introduced a Mo-14Re biodegradable alloy that addressed the key limitations of pure molybdenum for bioresorbable applications, including insufficient ductility, rapid degradation, and nephrotoxicity. Rhenium alloying significantly improved mechanical ductility, enhanced corrosion resistance, and reduced toxic molybdenum accumulation, while maintaining biocompatibility. In vivo experiments demonstrated complete endothelialization and no renal toxicity, establishing Mo-14Re as a promising candidate material for next-generation biodegradable vascular implants.