Fabrication of nano-hydroxyapatite/chitosan membrane with asymmetric structure and its applications in guided bone regeneration.

The development of guided bone regeneration (GBR) technique brings a promising alternative for bone defects and fracture healing. In this study, an asymmetric nano-hydroxyapatite/chitosan (n-HA/CS) composite GBR membrane was fabricated by means of solution-blending and solvent-evaporating in vacuum. The membranes were characterized using SEM, XPS and contact angle. It was found that the composite membrane displayed an asymmetric structure, in which the upper surface was CS and the under surface was a complex of n-HA and CS, and some interactions between n-HA and CS were also confirmed to exist. The contact angle testing showed that the under surface was more hydrophilic than the upper surface. The in vivo experiments demonstrated that the asymmetric composite membrane had the ability to make osteoblasts mineralize and promote loose bone calcified, and then accelerate the bone regeneration. Compared with CS membrane, the asymmetric composite membrane displays a better bone regeneration ability and is suitable for GBR membrane.