Biosoluble ceramic fiber reinforced poly(L-lactic acid) bone scaffold: degradation and bioactivity

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 degrees to 61.1 degrees 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.