title: RGD-conjugated copolymer incorporated into composite of poly(lactide-co-glycotide) and poly(L-lactide)-grafted nanohydroxyapatite for bone tissue engineering.
abstract: Various surface modification methods of RGD (Arg-Gly-Asp) peptides on biomaterials have been developed to improve cell adhesion. This study aimed to examine a RGD-conjugated copolymer RGD/MPEG-PLA-PBLG (RGD-copolymer) for its ability to promote bone regeneration by mixing it with the composite of poly(lactide-co-glycotide) (PLGA) and hydroxyapatite nanoparticles surface-grafted with poly(L-lactide) (g-HAP). The porous scaffolds were prepared using solvent casting/particulate leaching method and grafted to repair the rabbit radius defects after seeding with autologous bone marrow mesenchymal cells (MSCs) of rabbits. After incorporation of RGD-copolymer, there were no significant influences on scaffold's porosity and pore size. Nitrogen of RGD peptide, and calcium and phosphor of g-HAP could be exposed on the surface of the scaffold simultaneously. Although the cell viability of its leaching liquid was 92% that was lower than g-HAP/PLGA, its cell adhesion and growth of 3T3 and osteoblasts were promoted significantly. The greatest increment in cell adhesion ratios (131.2-157.1% higher than g-HAP/PLGA) was observed when its contents were 0.1-1 wt % but only at 0.5 h after cell seeding. All the defects repaired with the implants were bridged after 24 weeks postsurgery, but the RGD-copolymer contained composite had larger new bone formation and better fusion interface. The composites containing RGD-copolymer enhanced bone ingrowth but presented more woven bones than others. The combined application of RGD-copolymer and bone morphological protein 2 (BMP-2) exhibited the best bone healing quality and was recommended as an optimal strategy for the use of RGD peptides.
authors: Key Laboratory of Polymer Ecobiomaterials, State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
authors: Peibiao
authors: P
authors: Zhang
authors: Haitao
authors: H
authors: Wu
authors: Han
authors: H
authors: Wu
authors: Zhongwen
authors: Z
authors: Lù
authors: Chao
authors: C
authors: Deng
authors: Zhongkui
authors: Z
authors: Hong
authors: Xiabin
authors: X
authors: Jing
authors: Xuesi
authors: X
authors: Chen