Highly efficient singlet oxygen generation, two-photon photodynamic therapy and melanoma ablation by rationally
Zheng Zheng1, Haixiang Liu1, Shaodong Zhai2
1Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology (HKUST) Clear Water Bay Kowloon Hong Kong China tangbenz@ust.hk.
Abstract:
Photosensitizers (PSs) with multiple characteristics, including efficient singlet oxygen (1O2) generation, cancer cell-selective accumulation and subsequent mitochondrial localization as well as near-infrared (NIR) excitation and bright NIR emission, are promising candidates for imaging-guided photodynamic therapy (PDT) but rarely concerned. Herein, a simple rational strategy, namely modulation of donor-acceptor (D-A) strength, for molecular engineering of mitochondria-targeting aggregation-induced emission (AIE) PSs with desirable characteristics including highly improved 1O2 generation efficiency, NIR emission (736 nm), high specificity to mitochondria, good biocompatibility, high brightness and superior photostability is demonstrated. Impressively, upon light irradiation, the optimal NIR AIE PS (DCQu) can generate 1O2 with efficiency much higher than those of commercially available PSs. The excellent two-photon absorption properties of DCQu allow two-photon fluorescence imaging of mitochondria and subsequent two-photon excited PDT. DCQu can selectively differentiate cancer cells from normal cells without the aid of extra targeting ligands. Upon ultralow-power light irradiation at 4.2 mW cm-2, in situ mitochondrial photodynamic activation to specifically damage cancer cells and efficient in vivo melanoma ablation are demonstrated, suggesting superior potency of the AIE PS in imaging-guided PDT with minimal side effects, which is promising for future precision medicine.
