Construction of Cross-linked Polyethylenimine Derivative and Its Transfection in COS-7 Cells

Objective: To synthesize cross-linked Polyethylenimine derivative with modified procedure and investigate its cytotoxicity and transfection efficiency on COS-7 cells.Methods: PEI-Bu was synthesized by using PEI 800Da as a backbone and 1,4-Dibutanediol Chloroformate was used as a linker.The pDNA condensation ability of the polymer was evaluated by agarose gel electrophoresis.MTT assay was employed to measure the cytotoxicity of the polymer.Luciferase plasmid was used as the reporter gene to investigate transfection efficiency in COS-7 cells.Results: Gel retardation assay showed complete condensation of pDNA at w/w ratios exceeded 1.Cytotoxicity of PEI-Bu increased with the increasing of the concentrations.PEI-Bu showed lower cytotoxicity than PEI 25kDa at the same concentration.Transfection result indicated that the polymer performed the highest transfection efficiency at w/w 5,which was higher than that in commercially available PEI 25kDa(P0.01) and comparable with Lipofectamine 2000(P0.05).Conclusion: The polymer PEI-Bu displayed much lower cytotoxicity and significantly enhanced transfection efficiency than PEI 25kDa in COS-7 cells,Therefore,it would be a promising candidate for safe and efficient gene delivery in gene therapy.