Near-Infrared Ii Hemicyanine Dye with Large Stokes Shift Designed by Tict Regulation for Boosting Imaging-Guided Photothermal Therapy.

The serious threat that cancer poses to human health highlights the significance of early detection and effective treatment. The integration of fluorescence diagnosis and photothermal therapy in NIR-II has gained attention due to its high sensitivity, fast response, and non-invasiveness. Fluorescence, produced by the radiative relaxation process of electrons in a molecule, and photothermal, generated by the non-radiative relaxation process of electrons in a molecule, are competing photophysical processes. Hence, it is a challenge for the molecule to balance between the properties of fluorescence and photothermal. In this study, we designed a NIR-II hemicyanine with TICT character to obtain molecules with both better fluorescence and photothermal properties, utilizing positively charged pyridine salt and triphenylamine as electron acceptor and donor, respectively, and oxole as the conjugated π-bridge. HCY-995, one of the synthesized compounds, had a quantum yield of 0.09%, photothermal conversion efficiency of 54.90%, and a significant Stoke shift of 232 nm, which made it appropriate for the integration of photothermal therapy and high-resolution imaging. This study provides new insights into the development of NIR-II molecules with fluorescent and photothermal integrated properties. This article is protected by copyright. All rights reserved.