A 23 amino acid, bifunctional integrin-targeted synthetic oligopeptide was evaluated for ex vivo gene delivery to rabbit bone marrow stromal cells (BMSCs). Synthesis of the peptide (K)16GRGDSPC was performed on a solid-phase batch peptide synthesizer. BMSCs were transfected with plasmid DNA coding for luciferase by (K)16GRGDSPC and the transfection efficiency was assayed. The influences of chloroquine and polyethyleneimine on the transfection efficiency were also examined. The target specificity of (K)16GRGDSPC to mediate exogenous gene into BMSCs was analyzed using cell attachment test and gene delivery inhibition test. The results showed that the transfection efficiency of the oligopeptide vector was lower than that of Lipofectamine. But in the presence of endosomal buffer chloroquine or endosomal disrupting agent polyethyleneimine, the transfection efficiency of the vector was greatly enhanced. In addition, RGD-containing peptides inhibited BMSCs' attachment to the 96-well plates pretreated with fibronectin or vitronectin and significantly decreased the transfection efficiency of the oligopeptide vector. These studies demonstrated that oligopeptide (K)16GRGDSPC was an ideal novel targeted non-viral gene delivery vector, which was easy to be synthesized, high efficient and low cytotoxicity. The vector could effectively deliver exogenous gene into rat BMSCs.
To evaluate the biocompatibility of poly(lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol)(PLGA-ASP-PEG )tri-block copolymer in vitro,L929 fibroblast was co-cultured with the copolymer for cytotoxicity,hemolysis and pyrogen tests.And,compared with PLGA,the adhesiveness rate of the copolymer was calculated.The experimental results show that the toxicity gradation of the material was 0-1; L929 fibroblasts had a good cell morphology and proliferated rapidly on the surface of the material;hemolysis ratio was 3.08%;there was no pyrogen reaction.The adhesiveness of PLGA-ASP-PEG was better than that of the PLGA's(P<0.05).The results confirm that the PLGA-ASP-PEG has a good biocompatibility.
Poly (lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol)(PLGA-[ASP-PEG]) scaffold materials were linked with a novel nonviral vector (K)16GRGDSPC through cross linker Sulfo- LC-SPDP to construct a new type of nonviral gene transfer system. Eukaryotic expressing vector containing transforming growth factor beta 1 (pcDNA3-TGFβ1) was encapsulated by the system. Bone marrow stromal cells (BMSCs) obtained from rabbit were cultured on PLGA-[ASP-PEG] modified by (K)16GRGDSPC and TGF-β1 gene and PLGA-[ASP-PEG] modified by (K)16GRGDSPC and empty vector pcDNA3 as control. The expressions of osteogenic makers of the BMSCs cultured on the TGF-β1 gene-activated scaffold materials were found significantly higher than those of the control group (P<0.05). A brand-new way was provided for regulating seed cells to directionally differentiate into osteoblasts for bone defect restoration in bone tissue engineering.
