Li Kai Angew，Southern University of science and technology: ester substituted semiconductor polymers for monitoring tumor growth
Photoacoustic agents play an important role in improving imaging contrast and reliability of anti endogenous interference. In this work, Li Kai and others from Southern University of science and technology have synthesized a series of thiadiazole quinoxaline (TQ) semiconductor polymers (SPS). Their absorption ranges cover the nir-i to nir-ii regions.
The main points of this paper are as follows
1) The excited state s-bdt-tqe is a repeating unit of SPS. Due to the substitution of TQ segment by ester with strong electron defect, the excited state s-bdt-tqe exhibits large dihedral angle, narrow adiabatic energy and low radiation decay.
2) In addition, the stronger molecular motion will lead to higher recombination energy, which will further produce effective photoinduced nonradiative decay, which has been carefully studied and understood by theoretical calculation. Therefore, bdt-tqe SP nanoparticles with distorted intramolecular charge transfer (TICT) properties have higher nir-ii photothermal conversion efficiency (61.6%) and better photoacoustic tracking performance (more than 20 days) for in situ liver tumor growth.