Near infrared thermoluminescent liposome sensor for real-time monitoring of photothermal therapy and magnetic hyperthermia

Abstract

Liposomes are established in the clinic as drug delivery system, and can be designed for heat-triggered drug release. Thermal nanotherapies, like magnetic nanoparticle hyperthermia (MNH) and photothermal therapy (PTT), show great promise for cancer therapy and other diseases, but the great challenge of them is temperature detection. In this study, a thermoluminescent vesicle for real-time monitoring of PTT and MNH is developed. The temperature sensor is a liposome containing IR780 dyes incorporated in the membrane. For PTT, the liposome is the thermal agent and temperature sensor, while for MNH only the sensor, since the nanoheaters are Mn-based iron oxide nanoparticles. Mn-ferrite nanoparticles showed a good response at low field MNH conditions. The photothermal conversion efficiency of the liposomes altered from 11% to 22%. Thermal sensitivity varied from 0.3% to 5.0% and change after freeze-drying, while repeatability ranged from 0.91 to 0.98. Photostability studies of MNH and PTT with five heat-cooling cycles confirmed the temperature sensor application. In vivo and post-mortem studies using the B16F10 murine tumor model are reported. After intratumoral injection of the thermoluminescent vesicle a blue-like fluorescence peak shift of ≈20 nm is observed, which maintains the thermometry capabilities and reveals remotely the intratumoral temperature during PTT. The results demonstrate that the near-infrared thermoluminescent liposome is able to real-time monitoring the thermal therapy.