Calcium based siRNA coating: a novel approach for knockdown of HER2 gene in MCF-7 cells using gold nanoparticles

Surface functionalization of nanoparticles (NPs) for therapeutic siRNA delivery into cancer cells has gained interest. The present study was designed for surface functionalization of gold nanoparticles (AuNPs) for efficient siRNA delivery and knockdown in cancer cells. In order to achieve this objective, AuNPs were coated with HER2-siRNA in the presence of 11-mercaptoundecanoic acid (11-MUA), calcium chloride (CaCl2) and polyethyleneimine (PEI) in alternate charge bearing successive layers. MCF-7 cells were cultured and transfected with fabricated assembly of AuNPs. Cytotoxicity analysis revealed that the half inhibitory concentration (IC50) for the formulation was 45.35 nM  . Total RNA was isolated from transfected cells, reverse transcribed into complementary DNA (cDNA) and real-time polymerase chain reaction (RT-PCR) was performed. The RT-PCR based delta-delta Ct analysis in treated cells revealed a significant 18.94 times decrease (p<0.001) in the expression of HER2 gene standardized with ACTB housekeeping gene as compared to untreated cells, which makes this formulation a potent approach for siRNA delivery and  gene knockout.