ANIONIC NANOPARTICLES OF AlgS–Ca²⁺-siRNA ARE EFFICIENT CARRIERS OF siRNA TO HUMAN HEPATOCYTE CELL LINE

Over the past decade, small interfering RNA (siRNA) has intensively been explored owing to its potential in disease therapy. Yet, siRNA delivery in vivo is still a major challenge due to itsrapid degradation by nucleases, poor cellular uptake and rapid renal clearance following systemic administration. Thus, it is critical to develop an appropriate delivery system that will overcome these limitations and to improve the safety of potential RNAi-based therapeutics. We developed a novel siRNA delivery platform, based on the complexation of Alginate sulfate (AlgS) with siRNA, mediated by calcium ions bridges. Realizing the potential toxicity of cationic carriers, the AlgS–Ca²⁺-siRNA nanoparticles (AlgS-NPs) have a net negative surface charge of ~-8 mV. The chemical interaction between the three components constituting the AlgS-NPs was confirmed by XPS and TEM. Assessing the cellular uptake of AlgS-NPs in human hepatocyte cell line (HEPG2) by imaging flow cytometry analysis revaeled a highly efficient uptake, resulting in siRNA internalization in 89% of cells. Furthermore, results obtained by quantitative Real-Time PCR (qPCR) showed the silencing of the STAT3 gene to an extent of 90% without being cytotoxic to cells. In summary, the results obtained so far, indicate that AlgS-NPs may offer a promising platform for efficent delivery of therapeutic siRNA .