Chitosan grafted low molecular weight polyethylenimine deliver bone morphogenetic protein 2 gene to promote bone formation

• 1、Department of Pathology, School of Stomatology, Jilin University, Changchun 130021, China

Abstract：Through combining chitosan (CS) and low molecular weight polyethylenimine (PEI), we achieved a gene vector with high efficiency and low toxicity for delivering bone morphogenetic protein (BMP2) gene in promoting bone formation. The particle size and zeta potential of the PEI-CS/DNA complexs were characterized by dynamic light scattering and stable at 162nm and 26.7mV. With increasing the weight ratio, DNA binding ability of the copolymer increased. CS-PEI copolymer showed excellent biocompatibility in 293T and MC3T3-E1 cells at various concentrations. Compared with PEI 25K and Lipofectmine 2000, the transfection efficiency of CS-PEI was higher in MC3T3-E1 cells and comparable in 293T cells. In order to induce osteogenic differentiation in vitro, BMP2 gene delivered by CS-PEI copolymer showed a stronger effect on MC3T3-E1 preosteoblast cells in terms of the osteogenic related mRNA expression and mineralization compared with the control group. In addition, the secretion and function of BMP-2 were demonstrated via the appearance of phosphorylation of Smad1/5/8 in HELA cells after transfected. In vivo, the CS-PEI/BMP2 complex confirmed its ability to promote bone regeneration and excellent biological safety. Our study suggested that CS-PEI copolymer deliver the BMP-2 gene into MC3T3-E1 cells with highly promoted efficiency and provide a potential gene delivery system for promoting bone regeneration.

Keywords： chitosan；polyethylenimine；bone regeneration；bone tissue engineering；bone morphogenetic protein 2