Synthesis and application of magnetic nanoparticles (MNPs) in siRNA delivery to the retina

Abstract

AbstractIntroductionSmall interfering RNA (siRNA) is an important RNA interference tool that has found significant application in ocular therapy. For this reason, there is a considerable demand of siRNA delivery platforms able to effectively transfect cells within the retina. Up to now several strategies have been investigated for this application such as lipids, nanoparticles and polymers but in all the cases invasive injections are the only administration routes explored. Moreover, a major limitation shared by all these delivery systems is the lack of active targeting toward the posterior segment of the eye that hampers high transfection efficiencies.PurposeWe aim to synthesize and formulate a new magnetic nanoparticles‐mediated delivery technology that shall allow safe and efficient siRNA delivery to the retina assisted by magnetic targeting.Methods(1) Cationic MNPs have been synthesized, characterized, and their ability to form complexes with siRNA has been demonstrated by Zeta Potential. (2) The in vitro MNPs mediated gene silencing have been tested on green fluorescent protein (GFP)‐stably transfected cells (661W & RPE). Also, gene silencing of the endogenous glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) gene has been monitored. (3) Finally, the in vitro toxicity of the formulations has been determined in term of apoptosis, cell proliferation and protein production.ResultsMNPs were able to efficiently complex siRNA while maintain their size and charge. MNPs complexed with siRNA achieved high transfection efficiency and gene silencing of GFP as shown by fluorescence microscopy and flow cytometry. The knock‐down efficiency has been confirmed by targeting GAPDH by immunohistochemistry. Finally, proliferation, apoptosis and total protein content assays demonstrate the full biocompatibility of these gene delivery platforms.ConclusionsMagnetic nanoparticles are a promising platform for gene therapy in the context of ocular therapy and allow to achieve high transfection efficiencies in retinal cell lines.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement No 722717.