Titanium and its alloys are cornerstone biomaterials due to their high strength-to-weight ratio, excellent fatigue and corrosion resistance, biocompatibility, and ability to osseointegrate with bone. Their relatively low elastic modulus compared to stainless steels and Co–Cr alloys further enhances their suitability for biomedical applications. Performance is continually improved through alloy design (tailoring α and β phases), advanced manufacturing methods such as CNC machining and additive manufacturing, and surface engineering approaches. In particular, the formation of a stable TiO2 layer promotes corrosion resistance and cell attachment, while coatings and nanotexturing enhance osseointegration and provide antibacterial functionality. These attributes enable widespread use in orthopedic, dental, and cardiovascular implants. Emerging developments include smart implants with embedded sensors, multifunctional surfaces, and data-driven alloy design, aiming to further optimize mechanical performance, biological response, and long-term reliability. This review summarizes the processing techniques, properties, applications, and recent advances in titanium-based biomaterials.
Matthew Davidson, Subin Antony Jose, Mason Paul et al.· Metals· 0 citations
The global plastic pollution crisis demands a fundamental re-evaluation of materials systems beyond incremental improvements to fossil fuel-based polymers. Bioplastics, polymers derived from renewable biological feedstocks, biodegradable under defined conditions, or both, offer a chemically diverse and rapidly evolving platform for transitioning toward circular materials economies in which the value of carbon, energy, and material is retained across multiple use cycles. This review provides a comprehensive and critically organized account of the bioplastics field, spanning three generations of feedstock development from food crops through lignocellulosic residues to algae and waste streams; primary production pathways including microbial fermentation, ring-opening polymerization, and biosynthesis; forming processes from extrusion and injection molding to additive manufacturing; and the mechanical, thermal, and barrier properties that determine application fitness. Particular emphasis is placed on life cycle assessment, which reveals that bioplastics’ climate benefits are conditional on feedstock choice, land-use management, energy source at manufacturing, and end-of-life pathway, and that burden-shifting from greenhouse gas emissions to land use, water consumption, and eutrophication is a systematic risk requiring integrated LCA evaluation rather than single-metric optimization. The review further examines end-of-life recycling, composting, and biodegradation pathways; market applications across packaging, agriculture, automotive, biomedical, and electronics sectors; and the growing role of artificial intelligence and machine learning in accelerating materials design, process optimization, and lifecycle data management. Critical barriers to scale, such as cost premiums of 20–75% over conventional plastics, inadequate composting infrastructure, recycling stream contamination, regulatory fragmentation, and consumer labeling confusion, are systematically analyzed alongside mitigation strategies. The review concludes with a forward-looking discussion of emerging feedstocks, smart and functional bioplastics, and the policy and infrastructure investments required to translate the environmental promise of bio-based polymers into realized circular economy impact.
