Fig. 5
a Absorption spectra of nrGO (green) and nrGO-0 (gray) with (solid) or without (dash) DOX loading. Inset: comparison of drug loading capacity of nrGO-0 and nrGO. b Fluorescence spectra of DOX mixed with different weights of nrGO. c Fluorescence spectra of nrGO/DOX after treatment with different concentrations of GSH (0, 0.01, 0.05, 0.2, 0.5, 1, and 5 mM) for 6 h. d Plot of stimuli-induced DOX release from nrGO/DOX by acidic condition (pH 5), GSH (5 mM), 50 °C water bath heating, and their combinations, respectively. e Sequential multi-stimuli-responsive DOX release profile from nrGO/DOX complex under acidic condition (pH 5), GSH (5 mM), and 50 °C water bath heating