Advances in β-titanium alloys for safer and greener biomedical implants

In the biomedical field, titanium alloys have long been preferred for orthopedic and dental devices due to their excellent biocompatibility and mechanical strength, making them suitable for long-term implantation. However, recent findings indicate that certain alloying elements, such as vanadium, cobalt, and copper, may pose cytotoxic risks when present at higher concentrations or under specific conditions. As a response to these concerns, current research is focused on developing titanium alloys that feature a lower elastic modulus and improved compatibility with bone elasticity. It also aims to exclude potentially cytotoxic elements and incorporate advanced surface modifications, thereby providing effective solutions to these challenges. Based on these identified needs this review highlights the latest advancements in the design of β-Ti alloys through safer and greener methods. It places particular emphasis on pre-clinical in vitro and in vivo studies that evaluate the safety and performance of implants. Additionally, discusses the potential of artificial intelligence and computational methods for predicting and optimizing alloy properties. Unlike previous reviews that focus mainly on microstructure, mechanical behavior or specific clinical niches, this review includes alloy design and processing with pre-clinical evidence, regulatory and intellectual-property dimensions, and life-cycle and sustainability assessments. By linking β-Ti alloy development to circular-economy strategies, biodegradable metallic alternatives and emerging machine-learning tools for alloy prediction, the review provides a framework for the clinical translation of safer and greener titanium implants, offering a complete overview of the critical factors influencing the future development of titanium alloy implants for biomedical applications.