Hepatocyte-targeted gene transfection of galactosylated chitosan-graft low molecular polyethyleneimine/DNA complexes

To investigate the hepatocyte targeted specific property of galactosylated chitosan-graft-polyethyleneimine (GC-PEI)/DNA complexes in vitro and in vivo.

With the plasmid expressing enhanced green fluorescent protein (pEGFP-C1) as the reporter gene, the formation of GC-PEI/DNA complexes was induced to self-assemble in 0.01 mol/L phosphate buffered saline(PBS), 150 mmol/L NaCl, or 5% glucose solution (GS).The complexes were characterized by the particle size, Zeta potential, DNA binding and protection capacity, and further tested for cytotoxicity and hepatocyte targeted transfection activity.

With the GC-PEI/DNA mass ratio from 1:1 to 2.5:1,the GC-PEI/DNA complexes effectively bound and protected the DNA from degradation of DNaseI and the serum, which presented as a well-formed sphere or compacted nucleocapsid structure at a diameter of 50-200 nm. The GC-PEI copolymer showed no obvious toxicity in the tested cell lines. Acute toxicity assay revealed that the mice grew well in 2 weeks with GC-PEI dosage from 50 to 300 μg. The assay by flow cytometry and fluorescent microscope showed that the transfection efficiency in hepatocyte lines (L02, QSG7701/core) was higher than that in non-hepatocyte lines (SGC7901, HBE) in vitro. In vivo, the GFP was obviously expressed in the liver tissue and not expressed in other organs 48 h after the transfection.

GC-PEI copolymer may carry the exogenous gene specifically to hepatocytes in vitro and in vivo,which has very good liver targeted specific property.