Application Of Multifunctional Nano Drug Gene Vactor In Cancer Diagnosis And Treatment

Gene therapy means to treat diseases caused by genetic abnormalities by introducing exogenous genes into target cells.The effective,stable and sustainable expression of therapeutic genes is essential in gene therapy,which strongly relies on the assistance of gene carriers.Liposome,as one kind of gene carriers has attracted extensive attention due to itseasy preparation and modification,as well as the good biocompatibility.It can protect and facilitate expression target genes..This thesis is mainly focused on the preparation of liposome coated gold nanoparticles as gene carriers and investigation their function in gene expression.The contents are briefly shown as follows:1.Cationic liposome（DOTAP）and cholesterol（Chol）-coated gold nanoparticles（DOTAP/Chol-AuNPs）are prepared as gene carriers.The survival rate of MCF-7cells measured by MTT assay after being incubated with DOTAP/Chol-AuNPs is94.7%,which indicates that DOTAP/Chol-AuNPs have low cytotoxicity.Meanwhile,DOTAP/Chol-AuNPs show higher transfection efficiency compared with that of DOTAP/Chol in MCF-7 cells,which demonstrates that DOTAP/Chol-AuNPs have good performance in gene delivery.2.A novel gene carrier,DOTAP/Chol-PEG₂₀₀₀-AuNPs is synthesized by inserting DSPE-PEG2000 into liposome based nanocomposites.The results show that the addition of DSPE-PEG₂₀₀₀ does not significantly change the combining capability with DNA compared with that of DOTAP/Chol-AuNPs,while the transfection efficiency is distinctly decreased,which indicates that DSPE-PEG₂₀₀₀ is beneficial to decrease the non-specific endocytosis of gene carriers and DNA complexes during gene therapy.