Metal scaffolds for bone tissue engineering: materials, challenges, and clinical prospects

초록

Bone scaffolds remain essential in bone tissue engineering, with the material choice dictating both mechanical and regenerative success. Compared to polymers and ceramics, metallic scaffolds are highly valued for their superior strength and stability in load-bearing applications. Non-degradable metals, including titanium, tantalum, and stainless steel, provide excellent support but face significant challenges like stress shielding, wear debris, and the need for secondary removal surgeries. Conversely, degradable metals like magnesium, zinc, and iron offer temporary support while resorbing. However, their clinical use is currently hindered by uncontrolled corrosion kinetics, premature loss of mechanical integrity, and excessive ion release. Furthermore, cobalt-based alloys and nitinol are studied for their wear resistance and shape-memory traits, yet mismatched mechanics and poor biological integration restrict broader application. To overcome these critical hurdles, contemporary research emphasizes innovative alloy design, topology and porosity optimization, hybridization with polymers or ceramics, and advanced surface engineering through coating and functionalization. This review systematically categorizes these metallic biomaterials into non-degradable and degradable classes, thoroughly evaluating their inherent properties and clinical limitations. Finally, we highlight emerging alternative approaches and discuss future directions toward developing multifunctional metallic scaffolds that seamlessly combine mechanical reliability, bioactivity, and long-term safety for effective bone regeneration. © 2026 The Author(s).

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