Innovations and optimal design in scaffold materials: the key to vascularization in bone tissue engineering

Bone defects resulting from physiological or pathological processes are common in clinical practice, and bone grafting remains the primary treatment for large defects. However, grafting procedures are associated with relatively high recurrence risk and potential disease transmission. Moreover, scaffold materials widely used in bone tissue engineering often suffer from delayed vascularization, which significantly hampers the efficiency of bone regeneration. To address this challenge, numerous studies have focused on promoting the formation of functional vascular networks by optimizing scaffold design, utilizing advanced fabrication techniques such as 3D printing and electrospinning, and enabling controllable release of growth factors or therapeutic agents. This review systematically examines the selection of scaffold materials (including bioceramics, polymers and composite materials) and their influence on angiogenesis. It also explores the application of innovative fabrication methods in constructing biomimetic vascular structures to coordinate vascularization and osteogenesis. Recent studies have demonstrated that the angiogenic performance of scaffolds can be significantly enhanced through the ion-releasing properties and structural optimization of silicon-based materials, particularly when combined with advanced manufacturing technologies. The review aims to provide a comprehensive overview of multi-dimensional strategies and synergistic solutions for the effective treatment of complex bone defects in clinical settings.