Studies Of Novel Surface-mediated Gene Delivery

Gene delivery is the most significant part of gene therapy.Among various gene delivery strategies,surface-mediated gene delivery method plays a more and more important role in applications for disease treatment due to its local,site-specific delivery behavior and its long-term efficiency.It remains to be great challenges in this field to provide novel thoughts for improving existing surface-mediated gene delivery methods and to further demonstrate the unique advantages of surface-mediated gene delivery in specific in-vivo applications.Aiming at differentiated selective gene delivery between cancer cells and normals,improving transfection efficiency,and designing surface-mediated systems for in-vivo functional gene delivery,researches were performed with details shown in the following parts:1.Aiming at the selective gene delivery between cancer cells and normals via surface-mediated delivery,in this study,a matrix metalloproteinase(MMP)-sensitive breath figure-hydrogel(BF-MDG)surface was constructed by loading gene-containing hydrogels into the breath figure holes.The upper walls of BF-MDG were hydrogel-free areas which provided sites for cell adhesion,while the holes were filled with MMP-sensitive hydrogels which released DNA in a MMP-responsive manner and selectively transfected cells only when there were MMP-overexpressing cancer cells in the system.This study provids a method for achieving selective stimuli-responsive gene delivery,and gives new thought to the combination of stimuli-responsive gene delivery and biomedical implants.2.Aiming at further enhancing transfection efficiency,in this study,a photothermy-assisted surface-mediated gene delivery system was constructed based on polydopamine-polyethyleneimine codepositing surface(PDA-PEI).By introducing photothermal effects into the transfection process,the transfection efficiency into hard-to-transfect primary endothelial cells and the transfection efficiency of a large-size plasmid were significantly enhanced.Moreover,the up-regulation of transfection efficiency were due to facilitated DNA release and cell membrane disturbance caused by local hyperthermia.This study provides new strategies for improving transfection efficiency,especially for that of hard-to-achieve transfections via traditional methods.3.Aiming at the important role of transforming growth factor-?1(TGF-?1)in in-stent restenosis processes,this study constructed a functional gene delivery stent coating for the inhibition of in-stent restenosis,by loading plasmid DNA encoding TGF-?1-short hairpin RNA(TGF-?1-shRNA)onto the stents via layer-by-layer assembly.The polyelectrolyte films were able to transfect cells in-vitro and vessel tissue in-vivo,significantly down-regulated TGF-?1 expression,and demonstrated the effect to inhibit extracellular matrix overdeposition and neointimal hyperplasia.This study further illustrates the irreplaceable advantages of surface-mediated gene delivery for biomedical applications,and provides potential for designing cardiovascular implant materials against in-stent restenosis.