Viral vectors have been extensively investigated as the most efficient and commonly used delivery modalities for gene transfer [1
]. However, issues of immune response to viral proteins remain to be addressed. Recent efforts have focused on developing non-viral gene transfer systems, and significant progress has been made in this area [3
]. Non-viral delivery systems have potential advantages such as ease of synthesis, cell targeting, low immune response, and unrestricted plasmid size. Among non-viral delivery systems, nanoparticle-based systems have excited great interest among scientists due to the active surface properties, strong penetrability with small size, protective effect on genes, and low toxicity [6
However, a limitation of the non-viral delivery technologies is the lack of an intrinsic signal for long-term and real-time imaging of gene transport and release. Such imaging could provide important information on rational design of gene carriers. Currently, organic fluorophores are used to label gene delivery [11
], but the photobleaching problem prevents long-term tracking.
With the rapid development of surface chemical modification method and nanobiotechnology, nanoparticle-based non-viral-mediated systems will help to achieve the ability to traceable, safe, efficient, and targeted DNA delivery. Qi and Gao reported that a new quantum dot-amphipol nanocomplex allows efficient delivery and real-time imaging of siRNA in live cells [12
], but the nanocomplex cannot drive genes with magnetic targeting. Electron-dense gold nanoparticles (NPs) are reported to provide the highest imaging resolution in fixed cells due to their visibility under a transmission electron microscope [13
], but they do not allow real-time imaging of live cells.
Here, we report green fluorescent magnetic Fe3O4 nanoparticles as gene carrier and evaluated their performance and location in pig kidney cells. This work focused primarily on evaluating performance of the green fluorescent magnetic Fe3O4 nanoparticles as gene carrier in mammalian somatic cells, which is significant research for their further application in animal genetics and breeding. Magnetic nanoparticle gene carriers, as non-viral carriers, are not easily digested; have superparamagnetism, higher DNA carrying capacity, and powerful penetration ability; are convenient and low cost; and can drive target genes to express highly under external magnetic field. Moreover, magnetic fluorescent nanoparticles could provide an intrinsic signal for imaging of gene transport in the cells, which makes them a potential application prospect in animal genetics and breeding.