Fig. 3

A–F Results of intracellular drug delivery in cancer cells, which were incubated for 4 h at 37 °C. A–C, CLSM images of HeLa cells incubated with Au-Cys-MTX NCs (A), Au-Cys-DOX NCs (B), Au-Cys-MTX/DOX NCs (C). MTX were pretreated with Cy 5.5 for imaging the MTX ingredient. The red and yellow fluorescent contrasts indicate the presence of DOX and MTX, respectively. D–F, CLSM images of HepG2 cells incubated with Au-Cys-MTX NCs (D), Au-Cys-DOX NCs (E), Au-Cys-MTX/DOX NCs (F). G, H In vitro cell viability of HeLa cells (G) or HepG2 cells (H) treated with the Au NCs (a), the theoretical value of bulk DOX and MTX (b), the mixture of MTX and DOX (c), the mixture of Au-Cys-DOX NCs and Au-Cys-MTX NCs (d), and Au-Cys-MTX/DOX NCs (e) after incubation of 24 h. P < 0.05