Hemostasis-osteogenesis integrated Janus carboxymethyl chitin/hydroxyapatite porous membrane for bone defect repair

Barrier membranes with osteogenesis are desirable for promoting bone repair. Janus membrane, which has a bilayered structure with different properties on each side, could meet the osteogenesis/barrier dual functions of guided bone regeneration. In this work, new biodegradable Janus carboxymethyl chitin membrane with asym-metric pore structure was prepared based on thermosensitive carboxymethyl chitin without using any cross-linkers. Nano-hydroxyapatites were cast on single-sided membrane. The obtained carboxymethyl chitin/nano-hydroxyapatite Janus membrane showed dual biofunctions: the dense layer of the Janus membrane could act as a barrier to prevent connective tissue cells from invading the bone defects, while the porous layer (with pore size 100-200 mu m) containing nano-hydroxyapatite could guide bone regeneration. After implanted on the rat critical-sized calvarial defect 8 weeks, carboxymethyl chitin/nano-hydroxyapatite membrane showed the most newly formed bone tissue with the highest bone volume/total volume ratio (10.03 +/- 1.81 %, analyzed by micro CT), which was significantly better than the commercial collagen membrane GTR (R) (5.05 +/- 0.76 %). Meanwhile, this Janus membrane possessed good hemostatic ability. These results suggest a facile strategy to construct hemostasis-osteogenesis integrated Janus carboxymethyl chitin/hydroxyapatite membrane for guided bone regeneration.

Automated summary

A new biodegradable Janus carboxymethyl chitin membrane with an asym-metric pore structure was prepared, and nano-hydroxyapatite was cast on one side of the membrane. The obtained membrane showed dual biofunctions: the dense layer acted as a barrier to prevent connective tissue cells from invading the bone defects, while the porous layer containing nano-hydroxyapatite guided bone regeneration. In the rat critical-sized calvarial defect model, this Janus membrane promoted the most newly formed bone tissue compared to the commercial collagen membrane, and it also showed good hemostatic ability.