Degradable calcium deficient hydroxyapatite/poly(lactic-glycolic acid copolymer) bilayer scaffold through integral molding 3D printing for bone defect repair.

A novel method was developed for calcium deficient hydroxyapatite (CDHA) scaffold 3D printing, through which a bilayer scaffold was fabricated by the integral molding of individual CDHA and poly(lactic-glycolic acid copolymer) (PLGA). The hydration reaction of-tricalcium phosphate (TCP) was utilized to form CDHA, and a mixed solution of gelatin, glycerine and glutaraldehyde was applied as the dispersant and adhesive. The concentration of the glutaraldehyde (1‰(v/v)) and the mixing ratio of-TCP (0.6, 0.8, 1.0 and 1.2 g ml) were studied with regard to the effect on the forming ability of the CDHA ink. The influence of-TCP proportion (0.6, 0.8, 1.0 and 1.2 g ml) on the formation of CDHA was also researched in phase analysis, morphology and compressive strength measurements. The CDHA/PLGA bilayer scaffold was fabricated with a good combination of the two components by 3D printing. Thedegradation, cytotoxicity and cell proliferation behavior were studied. Meanwhile, theperformances in terms of surgical safety, biodegradation and osteogenic capacity were investigated with a cortical bone defect model in a rabbit femur. The results showed that the CDHA/PLGA bilayer scaffold had excellent biocompatibility and no cytotoxicity. The scaffolds were successfully implanted and presented remarkable osteogenic capacity within 6 months through analyses in radiography and histology. In conclusion, the method has a potential clinical application in diverse bone repair practices by varied 3D-printing fabrication.