Engineering a favourable osteogenic microenvironment by heparin mediated hybrid coating assembly and rhBMP-2 loading

Abstract

With the development of bone tissue engineering, it is a great challenge to fabricate a bioactive surface which can provide a favourable microenvironment for cell adhesion, migration and osteo-differentiation. Coating the as-prepared substrates with bioactive components is an effective method to induce osteogenesis. In this study, we designed a multi-layered hybrid coating containing hydroxyapatite nanoparticles, heparin and chitosan. Heparin is used to mediate the electrostatic assembly of hydroxylapatite nanoparticles with chitosan, as well as the subsequent recombinant human bone morphogenetic protein-2 (rhBMP-2) loading. Several independent pieces of evidence were provided to indicate the successful fabrication of the hybrid coating. Sustained release of rhBMP-2 by this coating was also achieved. The in vitro biological studies reveal that the hybrid coating system has excellent biocompatibility and can improve the osteo-differentiation especially for rhBMP-2 present on the coating surface. The results demonstrate that the proposed rhBMP-2 loaded hybrid coating can provide a favourable osteogenic microenvironment and has the potential to improve in situ bone repair due to its superior osteoconductivity as well as osteoinductivity.