(a) Fluorescence emission spectra of G5-TPGS conjugates, y-CDs, G5-TPGS@y-CDs complexes, and (G5-TPGS@y-CDs)-DOX complexes. (b) UV–vis spectra of G5-TPGS@y-CDs complexes, (G5-TPGS@y-CDs)-DOX complexes, and free DOX·HCl. Inset shows the photos of the (G5-TPGS@y-CDs)-DOX complexes (left) and G5-TPGS@y-CDs complexes (right) in aqueous solution. (c) Release kinetics of DOX from the (G5-TPGS@y-CDs)-DOX complexes at pH 5.5 and 7.4, respectively. (d) Fluorescence microscopic images of MCF-7/ADR cells incubated with free y-CDs, DOX·HCl, or (G5-TPGS@y-CDs)-DOX complexes for 6 h. Cells treated with PBS were used as control.