Multifunctional Nanoparticles As MRI Visible Transfection Agents

Gene therapy has become an important strategy for treating various of human diseases, for example, cancer. The clinical success of gene therapy intimately relies on the development of safe and efficient gene delivery systems. Compared with viral vectors, non-viral vectors are safe, simple to prepare and modify, and have larger gene encapsulation capability. Polyethylenimine (PEI) is one of the most efficient non-viral vectors. However, PEI is still limited as a gene carrier in clinical treatment, because of its high cytotoxicity in vivo. And, another important obstacle for treatment development is the inability to acquire the bioinformation about biodistribution and biofunction of the gene vectors in vivo non-invasively. In this study, we used stearic acid modified low molecular weight polyethylenimine (PEI600) to encapsulate SPIO nanocrystals to form nanoscopic therapeutic systems, Stearic-LWPEI-SPIO. Now Minicircle plasmid DNA is a powerful candidate for improving gene expression and prolonging the lifespan of gene expression. So The Stearic-LWPEI-SPIO systems combined with minicircle DNA. We found here that Stearic-LWPEI-SPIO nanocomposite nontoxic and highly potent in vitro gene transfection in MCF-7cells. Via gel electrophoresis measurements, cell toxicity studies, dynamic light scattering measurements (DLS) and magnetic resonance imaging (MRI), the results show that Stearic-LWPEI-SPIO nanocomposites could stably bind, protect and deliver mcDNA for gene transfection, while maintaining good magnetic properties and biocompatibility. In conclusion, this new Stearic-LWPEI-SPIO nanocomposite may provide opportunities in gene therapy.