Current Concept of Bioactive Glass-loaded 3D-Printed Alginate-based Scaffolds for Bone Tissue Engineering Applications

Abstract

Bone is a mineralized connective tissue composed of osteoblasts, osteocytes, and osteoclasts, and its integrity is essential for structural and physiological function. Defects arising from trauma, tumors, or developmental abnormalities often require surgical reconstruction to restore normal performance. Autografts and allografts have long served as standard treatments for bone repair, however, their usefulness is restricted by limited availability, donor‑site complications, and the potential transmission of underlying diseases. These challenges have accelerated interest in bone tissue engineering (BTE) as an alternative strategy capable of enhancing regeneration while reducing postoperative risks. Advances in three‑dimensional (3D) printing have introduced powerful technique for fabrication of scaffolds with precisely controlled architectures and tunable mechanical and biological characteristics. This technology enables the creation of porous constructs that mimic the structural complexity of native bone, supporting cell infiltration, nutrient transport, and vascularization. Effective scaffolds for BTE must demonstrate biocompatibility, biodegradability, appropriate strength and stiffness, and the ability to promote osteogenesis and angiogenesis. Among natural polymers, alginate (Alg) has become a prominent candidate due to its inherent biocompatibility, degradability, abundance, low cost, and non‑immunogenic nature. Its versatility makes it suitable for developing customized 3D‑printed scaffolds. Additionally, bioactive glasses (BGs) are widely incorporated into composite scaffolds because their composition closely resembles the mineral phase of bone. BGs significantly enhance osteoconductivity, support mineral deposition, and can improve the mechanical resilience of polymer-based constructs. This review highlights recent progress in 3D‑printed Alg-based scaffolds for BTE, emphasizing how advanced fabrication techniques and BGs incorporation contribute to improved biological performance and structural reinforcement.