Fig. 2. pH and light sensitivity of MRIN.

a Schematic illustration of pH- and light-triggered Cy5 fluorescence recovery mechanisms. b The photographic and TEM images of MRIN at pH 7.4 and pH 5.4 with or without 808 nm irradiation. Scale bar = 50 nm. c Cy5 fluorescence ratios as a function of pH values for MRIN at 37 °C. d pH-triggered Cy5 fluorescence recovery versus time profile upon hydrochloric acid (HCl) addition. e Light-triggered Cy5 fluorescence recovery and Cy7.5 photobleaching of MRIN. The percentage of Cy5 fluorescence recovery and Cy7.5 fluorescence decay versus time profile upon 808 nm irradiation (0.5 W cm⁻²). f The comparison of Cy5 fluorescence recovery by pH-induced micelles dissociation and light-induced Cy7.5 photobleaching. The Cy5 fluorescence signals were recorded using fluorescence spectrophotometer or IVIS in vivo imaging system. g Fluorescence images of MRIN in pH 7.4 and pH 5.4 PBS buffers with or without 808 nm irradiation.