Regulation of bone regeneration by chiral modified hydroxyapatite/chitosan scaffolds

Chirality is ubiquitous in nature, from the macroscopic to the microscopic. Natural bone has good hardness and toughness. It is composed of collagen and minerals and has chiral structures from the atomic scale to the macroscopic scale. It plays an important role in regenerative medicine. The design of bone-inspired bioscaffolds focuses on the surface roughness, three-dimensional structure and layered structure of the scaffold in order to build a microenvironment that is closest to the biological bone structure. However, the current bone repair materials do not reflect chiral structures. Therefore, this work selected lanthanum-doped hydroxyapatite/chitosan as the raw material, and added different percentages (10%, 30%, 50%, 70%, and 90%) of poly(L-lactide) (PLLA) to synthesize PLLHC-0, PLLHC-1, PLLHC-3, PLLHC-5, PLLHC-7 and PLLHC-9 chiral scaffold materials. Cell experiments have demonstrated that the cell survival rate and the relative activity of ALP at days 1, 7, and 14 in the PLLHC-5 scaffold group are 99.4%, 7.06, 8.64, and 11.84, respectively. In animal models, micro-CT analysis at 8 weeks showed that the BV/TV (%) of PLLHC-5 at 4 and 8 weeks reached 89.33% and 95.13%, which were significantly higher than those in other groups. All PLLHC-X scaffolds exhibited gradual degradation in vivo, while strongly promoting new bone formation and effective bone tissue repair. These results demonstrate that the PLLHC-5 scaffold exhibits the strongest osteogenic capability and represents a promising novel material for bone regeneration.