Functional polysaccharide-coated SPIONs for in vitro mRNA delivery in breast cancer cells

Abstract

RNA-based therapeutics have recently attracted great attention as a novel platform for the prevention and treatment of several pathological conditions, including COVID-19, cancer, diabetes, cardiovascular diseases, and others. However, despite their advantages compared to formerly established treatment modalities, which include an increased effectiveness and specificity and reduced toxicity, the efficient delivery of nucleic acids into the cells remains a major challenge. In the present study, novel mRNA carriers, based on superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with modified natural polysaccharide, were designed and synthesized. More specifically, two polysaccharide derivatives, namely oxidized dextran and quaternized chitosan, bearing aldehyde and cationic quaternary ammonium salt groups, respectively, were deposited onto the SPION surface. The hybrid nanoparticles were characterized in terms of their size, surface charge, magnetization and polymer content, and were next used to bind green fluorescent protein–mRNA and produce mRNA delivery vehicles. Biological assays on the T47D breast cancer cell line were employed to assess the nucleic acid binding effectiveness and cellular uptake of the nanoparticles and the cell proliferation, viability, migration and protein expression of the SPION treated cells. The hybrid particles coated with oxidized dextran showed higher stability, mRNA binding capacity, via Schiff base formation, and gene transfection efficiency, due to their smaller size, high polymer content and the effective cleavage of the polymer–gene covalent bonds in the acidic cancer cell compartment. The superior performance of these gene vectors, compared to the well-established cationic nanoparticle-gene complexes, render them highly attractive as mRNA therapeutics for further testing in (pre)clinical in vivo studies.