Fabrication And Evaluation Of Two Core-Shell Polycationic Gene Delivery Systems

Objective:To synthesis and evaluate PEG-block-Poly (L-glutamate bearing spermine) PEG-PGS and Aspartate-graft-polyethyleneimine (AEP-g-PEI) as polycationic gene delivery systems.Method:(1) The morphology of the PEG-PGS/SARS DNA complexes were observed by transmission electron microscopy and the particle size was determined using an electrophoretic light scattering spectrophotometer. The condensation ability of the PEG-PGS was evaluated by agarose gels. The cytotoxicity and the transfection efficiency of Hela,293T cells were also investigated by MTT and Luciferase Assay, respectively. GFP expression of PEG-PGS/pEGFP was observed by confocal microscopy after aerosol delivery to ICR mice. (2) The morphology of the AEP-g-PEI/SARS DNA complexes was observed by transmission electron microscopy. The condensation ability of the AEP-g-PEI was evaluated by agarose gels. The cytotoxicity and the transfection efficiency of MCF7 and A549 cells were also investigated by MTT assay. The expression of S-DNA encoded S protein was determined by Western Blot assay.Results:(1) The morphology of the PEG-PGS/SARS DNA complexes was spherical, the size was around 246.1±1.3 nm and the distribution was narrow. Agarose gel experiment shows the PEG-PGS can totally retard the DNA migration at weight ratio 3. MTT experiments showed that the cytotoxicity of the complexes were lower than the control group PEI/DNA complexes. The cell transfection experiments that the the transfection efficiency of the complexes in Hela,293T cells were significantly higher than the naked DNA (P<0.01), and corresponded to PEI/DNA complexes at N/P ratio 10. Furthermore, aerosol delivery of AEP-g-PEI/pEGFP showed the same GFP expression as that of PEI/pEGFP. (2) The morphology of the AEP-g-PEI/SARS DNA complexes was spherical, and the size was around 112.2 ± 26.2 nm and the distribution was narrow, agarose gel experiment shows the AEP-g-PEI can retard the S-DNA migration. The cytotoxicity of the AEP-g-PEI was lower than that of PEI at the same concentration. The S-DNA encoded S protein can be detected by Western blotting method.Conclusion:The studies indicated that the anionic polymer PEG-PGS, AEP-g-PEI shows the potential to be an effective gene carrier.