Extraordinarily enhanced gene transfection and cellular uptake by aromatic hydrophobicization to PEI25K

Abstract

Different from commonly used alkylation strategies, PEI25K was modified with rigid, highly hydrophobic aromatic moieties to develop superior gene vectors with multiple functions, including structural compatibility with the cell membrane as well as cooperative contribution of electrostatic and hydrophobic interactions to the transfer process. A facile preparation approach was proposed by directly reacting PEI25K with 5-benzyloxyl trimethylene carbonate (BTMC) while omitting reagent activation and catalyst aid. The hydrophobic interactions between PEI-BTMC molecules serves as hydrophobic “locks” to stabilize polyplexes. PEI-BTMC polyplexes were kept good stability in the presence of heparin and DNase. The transfections mediated by PEI-BTMC vectors were better than PEI25K control in different cell lines. Particularly in HeLa cells, such enhancement owing to BTMC attachment can reach even up to 150 times. Experimental data indicated that the highly enhanced transfection mediated by PEI-BTMC was possibly more dependent on the special functions caused by BTMC modification rather than the improved cell-biocompatibility. Confocal laser scanning microscopy (CLSM) studies revealed the considerably higher potency of PEI-BTMC in transporting DNA into HeLa cells in comparison with PEI25K. It is expected that useful information provided in the current study would prompt the advance of PEI-based gene vectors towards practical applications.