Tuning intramolecular charge transfer and spin-orbit coupling of AIE-active type-I photosensitizers for photodynamic therapy
Development of photosensitizers (PSs) featuring type-I reactive oxygen species (ROS) with aggregation-induced emission (AIE) properties is a judicious approach to overcome the deficit of conventional photodynamic therapy (PDT). However, it remains a challenge to design AIE-active type-I ROS PSs usin...
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Published in | Journal of materials chemistry. B, Materials for biology and medicine Vol. 1; no. 32; pp. 6228 - 6236 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
17.08.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | Development of photosensitizers (PSs) featuring type-I reactive oxygen species (ROS) with aggregation-induced emission (AIE) properties is a judicious approach to overcome the deficit of conventional photodynamic therapy (PDT). However, it remains a challenge to design AIE-active type-I ROS PSs using a simple theranostic scaffold paired with a delicate balance between intramolecular charge transfer (ICT) and large spin-orbit coupling (SOC) features to facilitate intersystem crossing (ISC) and hence to intensify triplet excitons for type-I ROS generation as well as to improve optical properties for the desired biomedical applications. In this work, a rationally designed series of PSs based on C-6-substituted tetraphenylethylene-fused benzothiazole-coumarin scaffolds, named
TPE-
n
CUMs
, were synthesized
via
a fused-ring-electron-acceptor (FREA) strategy, endowed with AIE properties in aqueous solution and thus self-monitoring type-I ROS generation under white-light irradiation to study the effects of diverse ICT and SOC potentials on their photochemical and optical properties. Both experimental and theoretical results revealed that the concomitantly increasing strengths of both ICT and SOC features promote type-I ROS generation by
TPE-
n
CUMs
. The key role of the SOC-promoting carbonyl group towards the ROS generation ability of
TPE-
n
CUMs
was then examined. Among
TPE-
n
CUMs
,
gem
-2OMe-TPE-2CUM
displayed highly efficient type-I ROS generation. Importantly,
gem
-OMe-TPE-1CUM
acts as a fluorescent indicator in HeLa cells (
in vitro
), revealing its excellent diffusion capability in both lysosomal and mitochondrial organelles with low dark toxicity, high cytotoxicity under white-light and remarkable PDT efficiency. Our study has thus elucidated a rationally designed strategy at the molecular level to fine-tune ICT and SOC features for the advance of AIE-active type-I ROS PSs, opening a new avenue for cancer treatment and image-guided therapy.
Judicious strategy to envision fine-tuning of intramolecular charge transfer (ICT) and spin-orbit coupling (SOC) features for the advances of AIE-active Type-I photosensitizers (PSs) for image-guided photodynamic therapy (PDT). |
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Bibliography: | 1 For ESI and crystallographic data in CIF or other electronic format see DOI 13 and C NMR and mass data. CCDC H Electronic supplementary information (ESI) available: Synthetic procedures and characterization; UV-vis and FL spectra; computational section; and 2175654 https://doi.org/10.1039/d2tb01224c 2175655 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2050-750X 2050-7518 |
DOI: | 10.1039/d2tb01224c |