Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

TLDR

Photothermal therapy (PTT) typically maintains lesion temperatures at 42–45 °C or higher, which kills cancer cells but also damages nearby normal tissues via heat conduction, reducing therapeutic accuracy. The study aims to use temperature‑feedback upconversion nanoparticles with photothermal material for real‑time microscopic temperature monitoring during PTT. This approach integrates upconversion nanoparticles and photothermal agents to monitor temperature at the nanoscale, enabling investigation of photothermal properties and guiding new PTT strategies. Microscopic temperatures reach levels sufficient to kill cancer cells while lesion temperatures remain low enough to spare normal tissue, allowing high‑resolution tumor ablation with minimal damage in vivo.

Abstract

Abstract Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42–45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo . Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.