An efficient receptor-mediated non-viral gene delivery formulation based on mono-pegylated recombinant human epidermal growth factor (EGF) was developed using a streptavidin-biotin system. Biotin-derivatized and mono-pegylated EGF was prepared by conjugating a biotin-PEG-NHS derivative to EGF and purified through a chromatographic method. Luciferase plasmid DNA and polyethylenimine (PEI) were complexed to form positively charged nanoparticles on which negatively charged streptavidin was first coated and then biotin-PEG-EGF conjugate was immobilized via streptavidin-biotin interaction. The EGF-PEG-biotin-streptavidin-PEI-DNA complexes were characterized in terms of their effective diameter and surface zeta (zeta)-potential value under various formulation conditions. The formulated complexes exhibited high transfection efficiency (approximately 10(8) in luciferase activity) with no inter-particle aggregation. This was attributed to enhanced cellular uptake of the resultant complexes via receptor-mediated endocytosis. Furthermore, in the presence of serum proteins, a slight decrease in transfection efficiency was observed due to the presence of PEG chains on the surface.
Copyright 2002 Elsevier Science B.V.