Advances in bioink-based 3D printed scaffolds: optimizing biocompatibility and mechanical properties for bone regeneration.

The development of bioink-based 3D-printed scaffolds has revolutionized bone tissue engineering (BTE) by enabling patient-specific and biomimetic constructs for bone regeneration. This review focuses on the biocompatibility and mechanical properties essential for scaffold performance, highlighting advancements in bioink formulations, material combinations, and printing techniques. The key biomaterials, including natural polymers (gelatin, collagen, alginate), synthetic polymers (polycaprolactone, polyethylene glycol), and bioactive ceramics (hydroxyapatite, calcium phosphate), are discussed concerning their osteoconductivity, printability, and structural integrity. Despite significant progress, challenges remain in achieving optimal mechanical strength, degradation rates, and cellular interactions. The review explores emerging strategies such as gene-activated bioinks, nanocomposite reinforcements, and crosslinking techniques to enhance scaffold durability and bioactivity. By synthesizing recent developments, this work provides insights into future directions for bioink-based scaffolds, paving the way for more effective and personalized bone regenerative therapies.