To evaluate the effectiveness of aptamer in targeting EpCAM cell surface protein and transporting 5-FU into the cells, anti-cancer activity of PEG-Au-NPs@5-FU, Apt-PEG-Au-NPs@5-FU and free 5-FU at different concentrations of 5-FU was evaluated against 2 cell lines including HT-29 (EpCAM+) and NIH/3T3 (EpCAM−) using MTT assay (Figure 5). The gene discussed is EPCAM; the disease is cancer.