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An Ester‐Substituted Semiconducting Polymer with Efficient Nonradiative Decay Enhances NIR‐II Photoacoustic Performance for Monitoring of Tumor Growth
Author(s) -
Zha Menglei,
Lin Xiangwei,
Ni JenShyang,
Li Yaxi,
Zhang Yachao,
Zhang Xun,
Wang Lidai,
Li Kai
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202010228
Subject(s) - photoacoustic imaging in biomedicine , photothermal therapy , intramolecular force , polymer , nanoparticle , absorption (acoustics) , photochemistry , chemistry , materials science , nanotechnology , optics , organic chemistry , physics , composite material
Photoacoustic agents have been of vital importance for improving the imaging contrast and reliability against self‐interference from endogenous substances. Herein, we synthesized a series of thiadiazoloquinoxaline (TQ)‐based semiconducting polymers (SPs) with a broad absorption covering from NIR‐I to NIR‐II regions. Among them, the excited s‐BDT‐TQE, a repeating unit of SPs, shows a large dihedral angle and narrow adiabatic energy as well as low radiative decay, attributing to its strongly electron‐deficient ester‐substituted TQ‐segment. In addition, its more vigorous molecular motions trigger a higher reorganization energy that further yields an efficient photoinduced nonradiative decay, which has been carefully examined and understood by theoretical calculation. Thus, BDT‐TQE SP‐cored nanoparticles with twisted intramolecular charge transfer (TICT) feature exhibit a high NIR‐II photothermal conversion efficiency (61.6 %) and preferable PA tracking of in situ hepatic tumor growth for more than 20 days. This study highlights a unique strategy for constructing efficient NIR‐II photoacoustic agents via TICT‐enhanced PNRD effect, advancing their applications for in vivo bioimaging.