Figure 5. Determination of the effect of nano-conjugates on the cell viability of Y79 retinoblastoma cells. A: Cytotoxic evaluation of transfection reagent and gold nanoparticles (AuNP) conjugates. The MTT assay shows no significant cellular cytotoxicity is associated when treated with (gold nanoparticles) AuNP or polyethyleneimine capped gold nanoparticles AuNP-PEI or EpCAM antibody conjugated polyethyleneimine capped gold nanoparticles AuNP-PEI-EpAb (EpCAM:PEI −0.5). B: Effect of siRNA loaded AuNP-PEI/AuNP-PEI-EpAb conjugates on Y79 cell viability. The MTT assay showed that the Y79 cells treated with AuNP PEI-EpAb loaded with 100 nmol of siRNA showed significantly decreased viability (47%) when compared with cells treated with AuNP-PEI-siRNA without antibody conjugation (68%; p<0.05). However, there was a significant decrease in the cell viability of the Y79 cells treated with AuNP-PEI loaded with 100 nmol of siRNA when compared with cells treated with100 nmol of naked siRNA (p<0.05).