Real-time monitoring of anticancer drug release in vitro and in vivo on titania nanoparticles triggered by external glutathione

The anticancer drug doxorubicin (DOX) appeared to adsorb efficiently on TiO2 nanoparticles (NPs) as evidenced by visible absorption and diffuse reflectance infrared spectroscopy data. The adsorbed drugs were found released in a controlled way by external glutathione (GSH). Fluorescence of DOX appeared to be quenched substantially by TiO2 NPs. The fabrication and release of DOX on TiO2 NPs were checked by monitoring the fluorescence. We could monitor real-time drug release in the live cell using fluorescence imaging techniques. By these methods, we were able to monitor up to a nanomolar amount of DOX release in vitro from TiO2 NPs triggered by external GSH. In vivo fluorescence images of DOX were obtained from the subcutaneous site in living mice after GSH treatment. On the basis of label-free fluorescence quenching measurements, a real-time release of DOX on TiO2 NPs can be monitored in vitro and in vivo after an external trigger of GSH.