Nanofiber scaffold for bone tissue engineering: Mechanism, challenge and future prospect

Table 1 Comparison of characteristics of nanofiber scaffolds with different material types

Types	Representative materials	Advantage	Disadvantage	Influence on “triple coordinated regulation”
Natural polymer	Collagen, gelatin, silk fibroin, chitosan	Inherent cell recognition site, excellent cell compatibility and biodegradability	The mechanical properties are poor, the degradation rate is fast and uncontrollable, and the difference between batches is large	Born with biological activity, it is easy for cells to adhere and recognize. However, rapid degradation leads to premature loss of topological structure and collapse of mechanical support, which not maintain long-term mechanical microenvironment regulation. Rapid degradation will lead to the sudden release of encapsulated growth factors, and it is difficult to realize long-term intelligent slow release
Synthetic polymer	PLGA, PCL, PLA, PLLA	Excellent and adjustable mechanical properties, controllable degradation rate and stable structure	The surface is usually biologically inert, hydrophobic and lacks cell-specific recognition sites	It can provide long-term and stable topological guidance and mechanical support. However, it must be endowed with biological activity through surface functionalization, otherwise it will be difficult for cells to use effectively
composite material	PCL/collagen, PLGA/bioactive glass	Combining the biological activity of natural materials and the mechanical/degradation controllability of synthetic materials	The preparation process is complex, and the interface bonding between the two materials is the key	Provide stable physical and mechanical signals; natural polymer components or bioactive ceramics provide biochemical signals and improve hydrophilicity

PLGA: Poly (lactic-co-glycolic acid); PCL: Polycaprolactone; PLA: Poly (lactic acid); PLLA: Poly-L-lactic acid.