| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 91 === Abstract
Conjugates of nanoparticles and DNA have been widely used in drug
delivery, gene therapy and gene transfection. A major goal of gene therapy is the efficient delivery of therapeutic gene into the target tissues.
In this study, magenetic nanoparticles (ferro fluid) were prepared by the method of alkaline precipitation. For the immobilization of poly -L- lysine, nanoparticles were incubated with EDC at the molar ratio of 4:1 for nanoparticle EDC . Transmission electron microscopy (TEM) micrographs of the magnetic nanoparticles showed that the particle size was not significantly changed by the binding of poly-L-lysine. The analysis of Fourier transform infrared (FTIR) spectroscopy confirmed the binding of poly-L-lysine onto magnetic nanoparticles. The magnetic nanoparticles were then complexed with plasmid pEGFP containing a reporter gene. Transfer of plasmid DNA into to Hep G2/C3A cells was achieved in the pulsed magnetic field. The transfection yield was evaluated by using flow cytometry to count the fluorescence of transfected cells. The expressed EGFP protein in the cell was observed on fluorescent microscope. The optimal magnetic field strength that could lead to the highest yield transfection was 0.72 T. A transfection yield of 67.8% could be achieved by exposure to the magnetic field for consequent three times with the DNA/magnetic nanoparticle complex.
Influences of magnetic field strength on the transfection level were studied for three transfection systems：naked DNA，poly-L-lysine/DNA complex and DNA/magnetic nanoparticle complex. All there three systems resulted in successful gene transfer of plasmid DNA into cells. However, the use of DNA/magnetic nanoparticle complex led to the highest transfection level, suggesting that the magnetic nanoparticles could enhance the transfection efficiency. This approach for gene transfection assisted by magnetic nanoparticles provides a novel tool to overcome fundamental limitations in gene therapy.
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