Development of a simple method for converting the lipid envelope of an inactivated virus to a gene transfer vector was achieved a couple years ago in the medical school of Osaka University. Hemagglutinating virus of Japan (HVJ; Sendai virus) envelope (HVJ-E) vector was constructed by incorporating plasmid DNA into inactivated HVJ particles. This HVJ envelope vector introduced plasmid DNA efficiently and rapidly into various cell lines, including cancer cells and several types of primary cell culture. In the present study, efficiency of gene transfer was found to be greatly enhanced by application of a magnetic field. Therefore, we developed a new type of magnet for magnetically enhancing and targeting gene transfection system by using vectors associated with ferromagnetic particles coated with positively/negatively charged biopolymers, which can help to enhance and target gene delivery with higher efficiency. For the transfection experiment in vitro, the HVJ-E vector was mixed with ferromagnetic particles coated with biopolymer and this mixture was added to cultured cells which were set up under the permanent magnet. The effect of the dose of the ferromagnetic particles on the transfection efficiency was discussed. In order to clarify the effect of magnetic field gradient on the accumulation possibility of the magnetic particles and the accuracy of the targeted site in the blood vessels, calculation of the applied magnetic force for the ferromagnetic particles inside the blood vessel was also performed.
In the recent progress of gene and cell therapy, novel drug delivery system (DDS) has been required for efficient delivery of small molecules/drugs and also the safety for clinical usage. We have already developed the unique transfection technique by preparing magnetic vector and using permanent magnet. This technique can improve the transfection efficiency. In this study, we directly associated plasmid DNA with magnetic nanoparticles, which can potentially enhance their transfection efficiency by magnetic force. Magnetic nanoparticle, such as magnetite, its average size of 18.7 nm, can be navigated by magnetic force and is basically consisted with oxidized Fe that is commonly used as the supplement drug for anemia. The magnetite particles coated with protamine sulfate, which gives a cationic surface charge onto the magnetite particle, significantly enhanced the transfection efficiency in vitro cell culture system. The magnetite particles coated with protamine sulfate also easily associated with cell surface, leading to high magnetic seeding percentage. From these results, it was found that the size and surface chemistry of magnetic particles would be tailored to meet specific demands on physical and biological characteristics accordingly. Overall, magnetic nanoparticles with different surface modification enhance the association with plasmid DNA and cell surface as well as HVJ-E, which potentially help to improve the drug delivery system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.