A comprehensive review of additively manufactured biomedical titanium alloys for bone tissue engineering: Biocorrosion, biomechanical, and biological properties
Amir Hossein Noorbakhsh Nezhad, E. Mohammadi Zahrani, Saba Mousavinasab, Akram Alfantazi
Abstract
In recent years, additive manufacturing has evolved rapidly in the healthcare industry to address rising demands for patient-specific, complex tissue scaffolds, vascular stents, dental and orthopedic implants, bone prostheses, and biomedical devices. Additively manufactured Ti-based scaffolds manifest a controllable combination of essential properties such as modulated porosity fraction, optimized porous architecture, tuned Young's modulus, and adjustable mechanical properties. Accordingly, the 3D-printed scaffolds favorably mimic natural bone structure and properties, eliminate stress-shielding effects, and enhance osteogenesis and osseointegration, offering significant advantages over traditional Ti-based bioimplants. Besides, microstructural features, hardness, wettability, surface properties, tensile and compression strength, fatigue life, and ductility affect the bioimplants' longevity and biological and biocorrosion performance. Herein, printability, in-vivo performance, and in-vitro characteristics of additively manufactured β and α + β Ti-based and Ni–Ti bio-alloys were holistically reviewed as promising alternatives to Ti–6Al–4V alloy in advanced manufacturing of bioimplant and tissue engineering scaffolds. The effects of AM processing parameters, post-surface and post-heat treatment on the microstructure, and the alloys' critical mechanical, biological, and corrosion properties were elucidated. We scrutinized the opportunities and challenges of using the most promising binary and multi-component AM β-Ti alloys with superb properties in bone tissue engineering for better clinical applications. It gave a foretaste of biomimetic design of novel 3D β-Ti scaffolds as local drug delivery systems for biological macromolecule-based drugs and growth factors in regenerative medicine and cancer therapy.