Anti‐Quenching NIR‐II J‐Aggregates of Benzo[c]thiophene Fluorophore for Highly Efficient Bioimaging and Phototheranostics

Abstract

Molecular fluorophores with the second near‐infrared (NIR‐II) emission hold great potential for deep‐tissue bioimaging owing to their excellent biocompatibility and high resolution. Recently, J‐aggregates are used to construct long‐wavelength NIR‐II emitters as their optical bands show remarkable red shifts upon forming water‐dispersible nano‐aggregates. However, their wide applications in the NIR‐II fluorescence imaging are impeded by the limited varieties of J‐type backbone and serious fluorescence quenching. Herein, a bright benzo[c]thiophene (BT) J‐aggregate fluorophore (BT6) with anti‐quenching effect is reported for highly efficient NIR‐II bioimaging and phototheranostics. The BT fluorophores are manipulated to have Stokes shift over 400 nm and aggregation‐induced emission (AIE) property for conquering the self‐quenching issue of the J‐type fluorophores. Upon forming BT6 assemblies in an aqueous environment, the absorption over 800 nm and NIR‐II emission over 1000 nm are boosted for more than 41 and 26 folds, respectively. In vivo visualization of the whole‐body blood vessel and imaging‐guided phototherapy results verify that BT6 NPs are excellent agent for NIR‐II fluorescence imaging and cancer phototheranostics. This work develops a strategy to construct bright NIR‐II J‐aggregates with precisely manipulated anti‐quenching properties for highly efficient biomedical applications.

A narrow-bandgap photothermal material based on a donor–acceptor structure for the solar–thermal conversion application

“…The absorption spectrum of 2TP-BBT in the solid state exhibits a significant red shift compared to that in the solution state. Remarkably, the absorption spectra of 2TP-BBT in tetrahydrofuran (THF) solution with different water contents showed that 2TP-BBT exhibited a redshift tendency with increasing water content, which indicated the formation of a J aggregated state 48–50 (Fig. S4, ESI†).…”

Adding Flying Wings: Butterfly-Shaped NIR-II AIEgens with Multiple Molecular Rotors for Photothermal Combating of Bacterial Biofilms

“…In previous studies, benzo­[ c ]­thiophene was found to be a perfect candidate to construct NIR-II AIEgens owing to its rich electron-donating feature for lowering band gap and large steric hindrance for guaranteeing AIE characteristics. − Herein, we designed three butterfly-shaped analogues, namely, 4TPA-TQ, 2TPA2TPE-TQ, and 4TPE-TQ in those benzo­[ c ]­thiophene units were utilized as an electron-rich donor/π-bridge, thiadiazolo [3,4- g ] quinoxaline (TQ) acted as an electron acceptor, and four TPA and/or TPE units connected on the periphery of fluorophores served as molecular rotors. As classical building blocks of AIEgens, the TPA/TPE moieties on one hand are advantageous to suppress the fluorescence quenching effect as nanoaggregates according to the mechanism of restriction of intramolecular motions (RIM) .…”

Reactive Oxygen Species-Responsive Sequentially Targeted AIE Fluorescent Probe for Precisely Identifying the Atherosclerotic Plaques

“…18 AIE fluorescent probes have been designed for imaging atherosclerotic plaques based on pathology. 19,20 For example, the excessive accumulation of ox-LDL triggers the formation of lipid droplets (LDs) in foam cells, a hallmark of AS. 21,22 These AIEgens, however, could nonspecifically stain other lipid-laden organelles and tissues (e.g., arterial walls and fatty liver), making them impractical for precise identification of the plaques for the potential clinic.…”

“…Fluorescence imaging has become as an indispensable modality because of its high sensitivity, excellent spatial resolution, and fast acquisition and image processing. , Recently, aggregation-induced emission luminogens (AIEgens) are an alternative class of fluorescent molecules, which are nonemissive when dissolved but strongly fluorescent in the aggregated state . AIE fluorescent probes have been designed for imaging atherosclerotic plaques based on pathology. , For example, the excessive accumulation of ox-LDL triggers the formation of lipid droplets (LDs) in foam cells, a hallmark of AS. , These AIEgens, however, could nonspecifically stain other lipid-laden organelles and tissues (e.g., arterial walls and fatty liver), making them impractical for precise identification of the plaques for the potential clinic. , …”