Poly(ethylene glycol)-modified thiolated gelatin nanoparticles for glutathione-responsive intracellular DNA delivery

摘要

Poly(ethylene glycol) (PEG)-modified thiolated gelatin (PEG-SHGel) anoparticles were developed as a long-circulating passively targeted delivery system that responds to intracellular glutathione concentrations to enhance DNA delivery and transfection.Reporter plasmid expressing enhanced green fluorescent protein (EGFP-N1) was encapsulated in the nanoparticles.DNA-containing gelatin (Gel) and thiolated gelatin (SHGel) nanoparticles were found to have a size range of 220 to 250 run,whereas surface modification with PEG resulted in particles with a slightly larger size range of 310 to 350 nm.PEG modification was confirmed by electron spectroscopy for chemical analysis (ESCA),where an increase in the ether peak intensities of the C1 s spectra corresponds to the surface presence of ethylene oxide residues.In addition,the PEG-SHGel nanoparticles released encapsulate plasmid DNA in response to varying concentrations of glutathione (up to 5.0 mM GSH in phosphate-buffered saline,or PBS).The stability of the encapsulated DNA was confirmed by agarose gel electrophoresis.Finally,from the qualitative and quantitative results of in vitro transfection studies in murine fibroblast cells (NTH3T3),PEG-Gel and PEG-SHGel nanoparticles afforded the highest transfection efficiency of the reporter plasmid.The results of these studies show that PEG-modified thiolated gelatin nanoparticles could serve as a very efficient nanoparticulate vector for systemic DNA delivery to solid tumors where the cells are known to have significantly higher intracellular GSH concentrations.