Biophysical study of novel oligoelectrolyte-based nonviral gene delivery systems for mammalian cells.

Background: Gene therapy is an important treatment for genetic and acquired diseases. The success of gene therapy is largely dependent on the development of suitable vectors for gene transfer. Vectors are needed to overcome cellular barriers and to achieve efficient DNA delivery with low cytotoxicity. In the present study, we synthesized and characterized a novel comb-like oligoelectrolyte nanocarrier, BG-2, as a nonviral gene delivery vector.

Methods: A novel surface-active oligoelectrolyte of comb-like structure was synthesized via controlled radical copolymerization using oligoperoxide Cu(+2) coordinating complex as a multisite initiator of graft copolymerization. The critical micellar concentration was determined by Nile Red fluorescence. Complex formation of DNA with BG-2 was determined by YOYO-1 fluorescence. The physicochemical properties of DNA in complex with BG-2 have been investigated by electrophoresis, dynamic light scattering and fluorescence spectroscopy. The BG-2/DNA complex was demonstrated by scanning electron microscopy. Interactions between BG-2/DNA complex and model membranes were also studied. The sensitivity of the DNA molecule, complexed with BG-2, against deoxyribonuclease I and serum nucleases was assessed by agarose gel electrophoresis. BG-2 efficiency in the transfection of HeLa cells was determined by measuring luciferase gene expression using a luminometer and cytotoxicity was also evaluated.

Results: BG-2 oligoelectrolyte was successful in overcoming cellular barriers as a result of forming stable and small sized complexes with DNA, interacting with model membranes in a desirable manner and protecting DNA from nuclease. The transfection efficiency was quite high and cytotoxicity was low.

Conclusions: BG-2 appears to be a promising nonviral vector with low cytotoxicity and efficient transfection properties.