Hexadecylated linear PEI self-assembled nanostructures as efficient vectors for neuronal gene delivery

Development of efficient and safe nucleic acid carriers is one of the most challenging requirements to improve the success of gene therapy. Here, we synthesized a linker, 3-(hexadecyloxy)-1-chloropropan-2-ol, and grafted it onto linear polyethylenimine in varying amounts to obtain a series of HD-1PEI polymers that were able to form self-assembled nanoparticles (SN). H-1-NMR spectrometry was used to determine the extent of grafting of the linker, HD, on to the WEI backbone. We further complexed the SN of HD-1PEI with plasmid DNA (pDNA) and the resultant nanoplexes were characterized by their size and zeta potential and further evaluated for their transfection ability and cytotoxicity in MCF-7 cells. In the series, the SN of HD-1PEI-3 (ca. 15% substitution) showed the highest transfection efficiency (similar to 91%) with non-significant cytotoxicity in comparison to the commercial transfection reagents. The in vitro gene knockdown study displayed - similar to 80% suppression of GFP gene expression by SN of HD-1PEI-3/pDNA/siRNA complex, whereas Lipofectamine (TM)/pDNA/siRNA complex could suppress the expression by only similar to 48%. The enhanced expression of luciferase gene using SN of HD-1PEI-3 in different vital organs of Balb/c mice also demonstrated the potential of the projected formulation for gene delivery. The encouraging results of SN of HD-1PEI-3 polymer for delivery of nucleic acids in vitro and in vivo paved the way to evaluate the potential of the same for neuronal siRNA delivery. The safe and efficient stereotaxic delivery of FITC-labeled siRNA against alpha-synuclein gene also confirms the potential applicability of HD-1EPI-3 SN as a vector for neuronal delivery.