Gold nanoparticle-mediated transfection of mammalian cells.

Mixed monolayer protected gold clusters (MMPCs) functionalized with quaternary ammonium chains efficiently transfect mammalian cell cultures, as determined through beta-galactosidase transfer and activity. The success of these transfection assemblies depended on several variables, including the ratio of DNA to nanoparticle during the incubation period, the number of charged substituents in the monolayer core, and the hydrophobic packing surrounding these amines. Complexes of MMPCs and plasmid DNA formed at w/w ratios of 30 were most effective in promoting transfection of 293T cells in the presence of 10% serum and 100 microM chloroquine. The most efficient nanoparticle studied (MMPC 7) was approximately 8-fold more effective than 60 kDa polyethylenimine, a widely used transfection agent.