Synthesis and development of chitosan-graft-polyethylenimine and chitosan modified PLGA nanoparticles for efficient siRNA drug delivery

In recent years, studies have shed light on the underlying mechanism on how dsRNA results in the loss of the targeted homologous mRNA. Such mechanism is known as RNA interference (RNAi). It is mediated by double-stranded small interfering RNA (siRNA). Nowadays, RNAi has been widely used as a potential therapeutic approach for treating a wide range of diseases, including cancer. Therefore, RNAi studies have been intensified to develop therapeutic agents based on this technique.;However, the use of siRNA is limited because of its rapid degradation and poor cellular uptake into cells. Carriers or vectors are needed for target delivery of siRNA or similar bioactive drugs. Because of restricted application, use of viral vectors is limited compared to non-viral vectors. Here, chitosan has been proposed as a non-viral carrier for siRNA due to several advantages, such as biodegradability, biocompatibility and high cationic potential. However, the transfection efficiency of chitosan-siRNA nanoparticles is still very low. To improve its transfection efficiency, we developed derivatives of chitosan which includes Chitosan-graft-Polyethylenimine (PEI-g-CHT) copolymer by an imine reaction and PLGA-CHT nanoparticles by using solvent evaporation method.;The composition of PEI-g-CHT copolymer was characterized by 1H NMR. Both derivatives of chitosan produced nano sized particles (measured by MALVERN Zeta Sizer: MA, USA) which were required to improve transfection efficiency. We found that as the concentration of chitosan increases, the average diameter and zeta potential of prepared nanoparticles increases. Prepared nanoparticles also showed excellent siRNA binding ability and high protection of siRNA from nuclease (RNase I) attack. The results of cytotoxicity assay revealed that nanoparticles had low cytotoxicity.;Finally, siRNA loaded nanoparticles were delivered into the targeted HEK 293 cell line and the GFP gene knockdown effect was investigated by using a fluorescent microscope (Carl Zeiss Axiovert 200 M: Germany). The results of which were further supported by the flow cytometry (FACS) data. The results of both the delivery systems showed potential for safer and cost-effective siRNA delivery.