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Background The reinforcement effect of fiber-reinforced polymer composites is usually limited because of the poor interfacial interaction between fiber and polymer, though fiber reinforcement is regarded as an effective method to enhance the mechanical properties of polymer. Methods In this study, nano-SiO2 particles grafted by 3-Glycidoxypropyltrimethoxysilane (KH560) were introduced onto the surface of 3-Aminopropyltriethoxysilane (KH550) modified carbon fiber (CF) by a self-assembly strategy to improve the interfacial bonding between CF and biopolymer poly (lactic acid) (PLLA). Results The results indicated that PLLA chains preferred to anchor at the surface of nano-SiO2 particles and then formed high order crystalline structures. Subsequently, PLLA spherulites could epitaxially grow on the surface of functionalized CF, forming a transcrystalline structure at the CF/PLLA interface. Meanwhile, the nano-SiO2 particles were fixed in the transcrystalline structure, which induced a stronger mechanical locking effect between CF and PLLA matrix. The results of tensile experiments indicated that the PLLA/CF-SiO2 scaffold with a ratio of CF to SiO2 of 9:3 possessed the optimal strength and modulus of 10.11 MPa and 1.18 GPa, respectively. In addition, in vitro tests including cell adhesion and fluorescence indicated that the scaffold had no toxicity and could provide a suitable microenvironment for the growth and proliferation of cell. Conclusion In short, the PLLA/CF-SiO2 scaffold with good mechanical properties and cytocompatibility had great potential in the application of bone tissue engineering.

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Poly (l-lactic acid) (PLLA) exhibits great potential as a kind of scaffold material for bone defect repair because of its good biocompatibility and processability, while the too slow degradation rate hinders its further application. In this study, the biosoluble ceramic fiber (BCF) was introduced into PLLA matrix, and the PLLA/BCF composite scaffold was manufactured by selective laser sintering (SLS). It was observed that water contact angle of the composite scaffold decreased from 87.4° to 61.1° with the increasing content of BCF, while the pH value raised from 6.6 to 7.8, and the molecular weight of PLLA decreased after immersion for 4 weeks. The mechanism of degradation acceleration was that the dissolution of BCF not only released OH− into solution environment and produced alkaline microenvironment, but also formed capillary channels on the interface between BCF and PLLA matrix, beneficial for the infiltration of water into the hydrophobic PLLA matrix, which contributed to the degradation both on the surface and in the interior of the matrix. Besides, the dissolution of BCF released Ca2+, Si2+ and Mg2+ simultaneously and absorbed PO43− from the environment, contributing to the formation of bone bonding between the scaffold and host bone. In addition, the introduced BCF improved the mechanical capacities of the scaffold via fiber breakage, fiber debond and fiber separation, and so on.