Cross-linked polyethylenimine-hexametaphosphate nanoparticles to deliver nucleic acids therapeutics

Abstract

Branched polyethylenimine (PEI; 25 kDa) as a nonviral vector exhibits high transfection efficiency and is a potential candidate for efficient gene delivery. However, the cytotoxicity of PEI limits its application in vivo. PEI was ionically interacted with hexametaphosphate, a compact molecule with high anionic charge density, to obtain nanoparticles (PEI-HMP). Nanoparticles were assessed for their efficacy in protecting complexed DNA against nucleases. The intracellular trafficking of nanoparticles was monitored by confocal microscopy. The cytotoxicity and transfection efficiency of PEI-HMP nanoparticles were evaluated in vitro. In vitro transfection efficiency of PEI-HMP (7.7%) was ~1.3- to 6.4-folds higher than that of the commercial reagents GenePORTER 2^TM, Fugene^TM, and Superfect^TM. Also, PEI-HMP (7.7%) delivered green fluorescent protein (GFP)-specific small interfering ribonucleic acid (siRNA) in culture cells leading to >80% suppression in GFP gene expression. PEI-HMP nanoparticles protected complexed DNA against DNase for at least 2 hours. A time-course uptake of PEI-HMP (7.7%) nanoparticles showed the internalization of nanoparticles inside the cell nucleus in 2 hours. Thus, PEI-HMP nanoparticles efficiently transfect cells with negligible cytotoxicity and show great promise as nonviral vectors for gene delivery.