Abstract

Background: Despite great hopes for small interfering RNA (siRNA)-based gene therapies, restrictions, including the presence of nucleases, reticuloendothelial system and undesired electrostatic interactions between nucleic acids and the cell membrane, limit the success of these approaches. In the last few decades, non-viral nucleic acid delivery vectors in nanosize with high biocompatibility, low toxicity and proton sponge effect have emerged as magic bullets to overcome these drawbacks.

Objective: This study aimed to develop poly(2-hydroxyethyl methacrylate) (pHEMA)-chitosan nanoparticles (PCNp), and to transfect green fluorescent protein (GFP)-silencing siRNA (GsiR) in vitro.

Methods: Firstly, PCNp displaying core-shell structure were synthesized and thereafter GsiR was encapsulated into the core of PCNp. The synthesized PCNp with/without GsiR were characterized using ultraviolet-visible (UV-vis)-spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, thermal decomposition, atomic force microscopy (AFM), scanning electron microscopy (SEM), zeta potential and dynamic light scattering (DLS) measurements. Encapsulation of siRNA into the pHEMA core coated with chitosan shell was demonstrated using fluorescence and FTIR spectroscopy.

Results: The surface charges of PCNp and PCNp-GsiR were found to be +39.5 and +40.2, respectively. In DLS analysis, an insignificant shift in the Z-average diameter of PCNp was observed from 109 nm to 133 nm using the encapsulation of GsiR. In comparison to other studied nanomaterials and a commercial transfection reagent, our findings suggest a promising GFP-silencing effect of 45%.

Conclusion: To our knowledge, we have obtained comparable silencing activity with the other studied equivalents despite using the lowest concentration of siRNA in existing literature.

Keywords: pHEMA-chitosan, nanoparticles, nanotherapeutics, siRNA delivery, GFP, gene silencing.

Graphical Abstract