Small molecule photothermal agents with ultra-high photothermal conversion efficiency: South University of Technology Kai team, \”German Applied Chemistry\”

Currently, light and heat therapy (PTT) has become a hot research new cancer treatments are, and develop near-infrared absorption and high photothermal conversion efficiency (PTCE) photothermal agents is an important factor to achieve the desired PTT efficacy, which for reduce the laser power density, and has important significance in light and heat treatment strategy at relatively low temperatures. Based on this, Department of Biomedical Engineering South University of Technology Kai Task Force reported of a high photothermal conversion efficiency of light and heat a small molecule agent It designs, and its application in the treatment of low-temperature solar thermal synergistic inhibition of HSP70 strategy in. In this work, the task group based on a design photoinduced nonadiabatic recession (of PIND) Effect of novel small organic molecules , using Apoptozole (Apo) thermal damage to cells inhibition of protein expression of HSP70 repair, 43 ℃ achieve efficient excitation of 808nm PTT tumor therapy. When such molecules imino motor with laser irradiation to an excited state, is affected by the strong twisted intramolecular charge transfer (TICT) effect, beneficial (CI) procedure by a conical cross way of non-radiative decay release of energy to the ground state, the process is as a visible light-induced non-adiabatic recession (of PIND) phenomenon. Compared to commercial probes ICG, the excited state of such release almost no fluorescence, it is possible to more efficiently convert light energy into heat energy, exhibits a up to 90% of the photothermal conversion efficiency.

In animal experiments, and precipitation of nano the surface of the cell penetrating peptide modified construct a kind of thermally responsive delivery system tumor cells, and 4T1 subcutaneously transplanted to nude mice as a tumor model study PTT hypothermia treatment of cancer C6TI / Apo-Tat-mediated nanoparticles. 2a, the mice tail vein injection C6TI / Apo-Tat 8 hours, 808nm laser irradiated mice, the tumor can be quickly warmed to 43 ºC, and stable plateaus. In C6TI / Apo-Tat and C6TI-Tat-mediated PTT therapy experiments tumors showed C6TI / Apo-Tat therapeutic effect on tumors significantly better than C6TI-Tat, and C6TI / Apo-Tat treatment group was significantly lower than tumor recurrence C6TI-Tat treatment group (FIG. 2b, 2c). Through the two treatment groups immunized orthotopic tumor tissue sections HSP70 and TUNEL staining analysis found (FIG. 2D), the heat can trigger the release of Apo effective to inhibit the tumor cells to repair thermal damage expression of the HSP70, resulting C6TI / Apo-Tat PTT low rate of apoptosis mediated tumor cells was significantly higher than group treatment C6TI-Tat, demonstrate the effectiveness of the combination treatment strategies. Therefore, the reported efficiency of the photothermal conversion agent photothermal molecular motor type, to avoid the conventional organic light-heat agent reference design requires long alkyl chains synthetically or complex substituent groups, the binding inhibition of thermal damage repair protein HSP70 expression mechanism, effectively break the limitations of traditional high-temperature treatment of PTT, which greatly reduces the risk of heat damage and other high-temperature ablation process of normal tissue near the tumor caused by providing a new way for the development of small molecules are highly efficient photothermal agents.

related work published in Angew. Chem. Int. Ed. . Department of Biomedical Engineering South University of Technology Professor Li Kaifu corresponding author, Research Associate Professor Xiang Ni investigation as the first author of the paper, Zhang Xun as a co-first author , group members Yang Guang , days Kang Yi made important contributions. The research team is particularly grateful to the National Science Foundation and the Shenzhen Branch Committee and other funding. Papers link: https: //www.onlinelibrary.wiley.com/doi/10.1002/anie.202002516 Task Force web page: Professor Li Kaifu http://faculty.sustech.edu.cn/lik/ Research Associate Professor Xiang Ni investigation http: // faculty .sustech.edu.cn / nizx /