In photothermal therapy for cancer treatment, hyperthermic effects can damage healthy tissues and inhibit therapeutic efficacy. Recently, the iChEM Prof. Fuyou Li’s group designed a carbon-coated core-shell upconversion nanocomposite for monitoring of microscopic temperature in photothermal process. Meanwhile, with the microscopic temperature information, high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo was achieved. Their research result was published on the Nature Communications, a top international journal under Nature, as a title of “Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature” (Nat. Commun. 2016, 7:10437 DOI:10.1038/ncomms10437).

Photothermal therapy (PTT), using photo-absorbing materials as heating sources, can damage the physiological functions of tumor tissues with the heat generate by those photo-absorbing materials. The current method to monitor PTT regards the entire lesion containing PTT agents as a macroscopic heat source and keep the overall temperature of the lesions at high level. Such overall apparent temperature can damage normal tissues adjacent to the lesions due to massive heat transfer, therefore, leading to more side effect and inhibiting the therapeutic accuracy of PTT. Prof. Li’s group demonstrated a kind of carbon-coated upconversion nanocomposite for monitoring of microscopic temperature in photothermal process. Under laser irradiation, the carbon shell serves as an excellent photothermal agent for cancer therapy and simultaneously heats up the nanocomposite. By analysing the changes of temperature sensitive upconversion luminescence emitted from the nanocomposite during the photothermal process, they found that microscopic temperature is much greater than the temperature at macroscopic level. By utilizing this phenomenon, they realized cell selective photothermal ablation under mild apparent temperature without harming adjacent non-labelled cells. High spatial resolution photothermal ablation in vivo of tumour with minimal damage to normal tissues was also realized at low apparent temperature. Their approach relying on a temperature-feedback photothermal agent indicated that an effective photothermal treatment with high accuracy could be realized under moderate conditions. The significance of this work is to use a microscopic temperature-feedback system to point out an optimized irradiation dose for facile photothermal therapy, which is different from the common understanding and cannot be achieved by previous macroscopic temperature measuring method.



Ph.D student Xingjun Zhu and Prof. Wei Feng et al. accomplished this work. National Basic Research Program of China, National Natural Science Foundation of China and the CAS/SAFEA International Partnership Program for Creative Research Teams offered financial support.

paper link：http://www.nature.com/ncomms/2016/160204/ncomms10437/full/ncomms10437.html