Authors: M.R. Papasani, D. Pokharel, A. Giri, V.V.R. Sai, P.J. Hrdlicka, R.A. Hill
Affilation: University of Idaho, United States
Pages: 358 - 360
Keywords: gene knockdown, oligo-ethylene glycol, gold nanoparticales
Small interfering RNAs (siRNAs) are useful agents for gene knockdown. We have taken a systematic approach to investigate the use of GNP as delivery platforms for firefly luciferase (FFL) siRNAs and the effect of passivation and transfection agents on GNP-siRNA conjugate gene knockdown efficacy. 3T3-L1 cells expressing the FFL gene (3T3-L1-FFL cells) were transfected with GNP-FFL-siRNA, GNP-siRNA + oligoethylene glycol (GNP-siRNA-OEG) or GNP-siRNA + lipofectamine for 24 h and luciferase reporter assays were conducted. Three different control experiments were also conducted. 3T3-L1-FFL cells were incubated with (a) FFL-siRNA + lipofectamine (positive gene knockdown control) (b) scrambled siRNA + lipofectamine (negative gene knockdown control) and (c) GNP only. No gene knockdown was observed in cells incubated with GNP alone. The greatest efficacy was observed in the FFL-siRNAs + lipofectamine (positive gene knockdown control), FFL gene expression being reduced to 29% of the negative control level. GNP-siRNA-OEG induced high efficacy gene knockdown, 39% of negative control, while GNP-siRNA +lipofectamine showed intermediate gene knockdown efficacy, 65% of negative control. However, no knockdown was observed with GNP-siRNA. These results suggest that OEG passivation has a beneficial influence on cell uptake or intracellular routing of GNP-siRNA conjugates to the cytoplasm or both and thus improving siRNA efficacy.