Objective:To investigate the effect of PEG-PEI/Fe3O4 Nano-magnetic fluid-TK on Apoptosis of liver cancer cells(HepG2)in vitro.Methods:Construcr ecombinant plasmid PEGFP-AFP-TK was constructed

which was delivered by nano-magnetic fuilds into AFP positive HepG2 cells and AFP negative SMMC7721 cells.The fluorescence was detected in order to evaluate the transfection rate 12h after transfection RT-PCR and Western blot were used to detect expression of HSV-TKgene at 48 h after transfection.MTT assay was used to evaluate the effect of HSV-TK on the proliferation of HepG2 cells

Flow cytometry was used to analyze the apoptosis of HepG2 cells.Results:Nano-Magnetic fluids delivered plasmid PEGFP-AFP-TK into HepG2 cells and HSV-TK gene was successfully expressed.The transfection eficacy of nano-magnetic fluids was superior than lipofectamine in HepG2 cells.RT-PCR and Western blot demonstrated that TK gene was expressed in HepG2 cells after being transfected with nano-magnetic fluids/PEGFP-AFP-TK.MTT and flow cytometry showed HSV-TK gene exerts a cell-killing effect.Conclusions:Nano-Magnetic fluids could successfully deliver PEGFP-AFP-TKinto HepG2 cells and induce expression of HSV-TK

it may become a promising gene vector for liver cancer gene therapy.AFP enhancer can specifically enhance the expression of target gene within the cell with positive AFP.