Combining Inulin Multifunctional Polycation and Magnetic Nanoparticles: Redox-Responsive siRNA-Loaded Systems for Magnetofection

Superparamagnetic Iron Oxide Nanoparticles (SPIONs) are recognized as one of the most promising agents for theranostic applications. Among methods designed for siRNA delivery, magnetofection, that is, nucleic acid cell uptake under the influence of a magnetic field acting on magnetic nucleic acid vectors, is emerging as a unique approach to combining advantages such as strong improvement of the kinetics of the delivery process and the possibility of localizing nucleic acid delivery to an area where the magnetic field is applied. This paper reports on the preparation of siRNA loaded magnetoplexes—named ICD@SS@SPIONs/siRNA—by controlled crosslinking, in the presence of SPIONs, of the polycation INU-C-DETA, synthesized starting from the polysaccharide inulin by grafting diethylenetriamine and cystamine molecules. The obtained ICD@SS@SPIONs/siRNA have suitable chemical-physical characteristics to be employed for iv administration and are also able to release siRNA in a redox-triggered manner thanks to intracellular glutathione (GSH) mediated reduction of disulphide bridges formed during the crosslinking process. Moreover, ICD@SS@SPIONs/siRNA are able to produce magnetic targeting in vitro on breast cancer cells, without appreciable cyto- and hemo-toxic effects, in a wide range of concentrations. Finally, protein binding to nanoparticles revealed that obtained systems are potentially longer circulating and applicable as a smart multifunctional agents for cancer therapy.