A chloroquine-loaded Prussian blue platform with controllable autophagy inhibition for enhanced photothermal therapy

Insufficient and heterogeneously distributed heat commonly leads to the incomplete elimination and recurrence of tumors. Inspired by the fact that autophagy is essential for cell survival in response to harmful stresses, a near-infrared (NIR) light responsive chloroquine (CQ, a well-known autophagy inhibitor) delivery system, consisting of phase-changing material (1-tetradecanol, PCM) and hollow mesoporous Prussian blue nanoparticles (HMPBs), is reported here to deliver CQ to the tumor region to augment the efficacy of photothermal therapy (PTT). In vitro thermosensitive CQ release assays demonstrated that precise "on-off" release profiles of CQ could be readily manipulated, owing to the excellent photothermal conversion abilities of HMPBs and the solid-to-liquid phase change properties of the PCM under NIR light illumination. Furthermore, targeted autophagy inhibition in cancer cells could remarkably amplify the cell-killing efficiency of PTT, leading to synergistic cancer suppression at mild therapeutic temperatures. Therefore, this work is expected to depict an effective strategy for the design and construction of a thermally responsive CQ delivery platform for modulating autophagy inhibition in tumors to reinforce the efficacy of PTT.