Anhydride chemistry-based hexanoylation of polyethylenimine increases transfection efficiency and expression of tagged DNA for therapeutic proteins in cultured cells

Transfection of nucleic acid molecules into mammalian cells can be facilitated using viral vectors, electroporation, or biocompatible cationic materials. However, safety issues and the requirement of specialized equipment limits the use of viral vectors and physical methods of transfection like electroporation and microinjection, respectively. Biocompatible cationic lipids and polymers like branched-polyethyleneimine (bPEI) have a wide transfection range and are user-friendly in most applications. However, bPEI exhibits low transfection efficiency in most cell types. In the present work, we have crosslinked the hexanoyl group to bPEI using anhydride chemistry to enhance its efficiency as a transfection reagent. The efficient association of hexanoyl group to bPEI was assessed using Fourier-transform infrared spectroscopy and other physicochemical methods. Hexanoyl-modified bPEI (FA6-bPEI) was found to exhibit significantly enhanced transfection efficiency in both cell lines and cultured primary cells, as compared to native bPEI and the commercially available transfection reagent, Lipofectamine 3000. Furthermore, our in vitro studies indicated that FA6-bPEI can be used for robust transfection for increased production of therapeutic proteins in a cell culture-based system. These results suggested that hexanoyl-modified bPEI can serve as an efficient transfection reagent for studies on hard-to-transfect cells and for enhanced production of therapeutic proteins in vitro.