Promising gene delivery system based on polyethylenimine-modified silica nanoparticles

This article reports on the synthesis and full characterization of innovative silica-based nanoparticle composed of fumed silica as a core decorated with polyethylenimine (PEI) with different molecular weights (25, 10 and 1.8 kDa). Wide range of analytical, spectroscopic, and microscopic methods (TEM, DLS, zeta potential, elemental analysis (EA), TNBS and FTIR) were used to characterize the nanoparticles. Furthermore, transfection efficiency of these nanoparticles as non-viral vector was examined. The silica-PEI conjugates retained both the ability of PEI to fully condense plasmid DNA at low N/P ratios and suitable buffering capacity at the endosomal pH range. PEI-functionalized silica remarkably enhanced EGFP-N1 gene expression in murine neuroblastoma (Neuro-2A) cells up to 38 folds compared to PEI 25 kDa. Meanwhile the results of the cytotoxicity assays indicated that these silica-PEI conjugates have acceptable level of viability.