Highly Efficient Photosensitizers with Molecular Vibrational Torsion for Cancer Photodynamic Therapy

Xiao Zhou; Chao Shi; Saran Long; Qichao Yao; He Ma; Kele Chen; Jianjun Du; Wen Sun; Jiangli Fan; Bin Liu; Lei Wang; Xiaoqiang Chen; Laizhi Sui; Kaijun Yuan; Xiaojun Peng

doi:10.1021/acscentsci.3c00611

Highly Efficient Photosensitizers with Molecular Vibrational Torsion for Cancer Photodynamic Therapy

ACS Cent Sci. 2023 Jul 17;9(8):1679-1691. doi: 10.1021/acscentsci.3c00611. eCollection 2023 Aug 23.

Authors

Xiao Zhou¹, Chao Shi², Saran Long¹, Qichao Yao¹, He Ma¹, Kele Chen¹, Jianjun Du¹, Wen Sun¹, Jiangli Fan¹, Bin Liu³, Lei Wang³, Xiaoqiang Chen³, Laizhi Sui⁴, Kaijun Yuan⁴, Xiaojun Peng^{1

3}

Affiliations

¹ State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China.
² College of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, P. R. China.
³ State Key Laboratory of Fine Chemicals, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, P. R. China.
⁴ State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China.

Abstract

The development of highly effective photosensitizers (PSs) for photodynamic therapy remains a great challenge at present. Most PSs rely on the heavy-atom effect or the spin-orbit charge-transfer intersystem crossing (SOCT-ISC) effect to promote ISC, which brings about additional cytotoxicity, and the latter is susceptible to the interference of solvent environment. Herein, an immanent universal property named photoinduced molecular vibrational torsion (PVT)-enhanced spin-orbit coupling (PVT-SOC) in PSs has been first revealed. PVT is verified to be a widespread intrinsic property of quinoid cyanine (QCy) dyes that occurs on an extremely short time scale (10^-10 s) and can be captured by transient spectra. The PVT property can provide reinforced SOC as the occurrence of ISC predicted by the El Sayed rules (¹ππ*-³nπ*), which ensures efficient photosensitization ability for QCy dyes. Hence, QTCy7-Ac exhibited the highest singlet oxygen yield (13-fold higher than that of TCy7) and lossless fluorescence quantum yield (Φ_F) under near-infrared (NIR) irradiation. The preeminent photochemical properties accompanied by high biosecurity enable it to effectively perform photoablation in solid tumors. The revelation of this property supplies a new route for constructing high-performance PSs for achieving enhanced cancer phototherapy.