Chiral mesostructured hydroxyapatite on 3D macroporous coralline scaffolds for enantio-selective osteogenesis

Abstract

Chirality is ubiquitous in nature from the macroscopic to microscopic scale, and plays an important role in life. Natural bone combines stiffness and toughness, and is formed by assembling collagen and minerals with a chiral mesostructure from the atomic to macroscopic scales. Bone inspired bio-scaffolds have been extensively investigated to construct the microenvironment closest to bone structure, including roughened surface, three dimensional structure and hierarchical structure. However, the chiral hierarchical structure is not reflected in the current bone repair materials. Here, we designed a bone repair scaffold chiral mesostructured hydroxyapatite on corallite (CMHAP@CL) for osteogenesis promotion in vivo, which integrates a three-dimensional porous structure, hierarchical structure and chiral mesostructure. The CMHAP films with thicknesses of ∼13.6 μm were grown on 3D microporous (aperture 100–300 μm) CL substrates with chiral hierarchical structures ranging from the atomic to macro scale. We found that the L-CMHAP@CL scaffolds synthesized with L-tartaric acid accelerated angiogenesis and osteogenesis, whereas the D-CMHAP@CL and Ach-MHAP@CL scaffolds synthesized with D-tartaric acid and free chiral molecule had a weaker effect. This chiral selectivity was speculated to be derived mainly from the bioadaptivity between the space configuration of the osteoblast and the chiral hierarchical structure. These findings will facilitate the development of the design of biomaterials for bone regeneration and clinical application.