Biomacromolecules. 2016 Mar 14;17(3):818-29. doi: 10.1021/acs.biomac.5b01543.
Enhanced in Vitro Mineralization and in Vivo Osteogenesis of Composite Scaffolds through Controlled Surface Grafting of L-Lactic Acid Oligomer on Nanohydroxyapatite.
Wang Z 1,2, Xu Y 3, Wang Y 1, Ito Y 4, Zhang P 1, Chen X 1.
1Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, PR China.
2University of Chinese Academy of Sciences, Beijing 100039, PR China.
3Department of Medical Cosmetology, The First Affiliated Hospital of Xiamen University , Xiamen 361003, PR China.
4Nano Medical Engineering Laboratory and ⊥Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
Nanocomposite of hydroxyapatite (HA) surface grafted with L-lactic acid oligomer (LAc oligomer) (op-HA) showed improved interface compatibility, mechanical property, and biocompatibility in our previous study. In this paper, composite scaffolds of op-HA with controlled grafting different amounts of LAc oligomer (1.1, 5.2, and 9.1 wt %) were fabricated and implanted to repair rabbit radius defects. The dispersion of op-HA nanoparticles was more uniform than n-HA in chloroform and nanocomposites scaffold. Calcium and phosphorus exposure, in vitro biomineralization ability, and cell proliferation were much higher in the op-HA1.1 wt %/PLGA scaffolds than the other groups. The osteodifferentiation and bone fusion in animal tests were significantly enhanced for op-HA5.2 wt %/PLGA scaffolds. The results indicated that the grafted LAc oligomer of 5.2 or 9.1 wt %, which formed a barrier layer on the HA surface, prevented the exposure of nucleation sites. The shielded nucleation sites of op-HA particles (5.2 wt %) might be easily exposed as the grafted LAc oligomer was decomposed easily by enzyme systems in vivo. Findings from this study have revealed that grafting 1.1 wt % amount of LAc oligomer on hydroxyapatite could improve in vitro mineralization, and 5.2 wt % could promote in vivo osteogenesis capacity of composite scaffolds.