Biomimetic Collagen Nanofibrous Materials for Bone Tissue Engineering

Hierarchical assemblies of nanofibres are ubiquitous in nature. Mineralized type I collagen is the basic building block of hierarchically organized, highly complex structures of bone tissue. As a biomaterial, collagen is widely utilized in biomimetic nanofibrous matrix fabrication due to its inherent biocompatibility and widespread occurrence in nature. Nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibres for tissue regeneration. The emergence of electrospinning techniques provides a new opportunity to fabricate nano-collagen fibres for bone tissue engineering. By orchestrating major parameters, collagen fibres with different components (pure or blended), sizes (nanometre to micrometre) and surface properties (mineralized or modified by functional bioactive molecules) have been developed and their effects on bone cell adhesion, proliferation, migration and differentiation evaluated. This review briefly introduces natural mineralized collagen structures in bone, biomimetic mineralization and bone grafts, and in vitro mineralization of collagen nanofibres fabricated by using three major techniques-molecular self-assembly, electrospinning, and phase separation. Their applications in bone tissue engineering are also discussed. We highlight the electrospinning technique in collagen nanofibre fabrication and its great potential for bone tissue regeneration.