Real‐Time and High‐Resolution Bioimaging with Bright Aggregation‐Induced Emission Dots in Short‐Wave Infrared Region

Abstract

Fluorescence imaging in the spectral region beyond the conventional near-infrared biological window (700-900 nm) can theoretically afford high resolution and deep tissue penetration. Although some efforts have been devoted to developing a short-wave infrared (SWIR; 900-1700 nm) imaging modality in the past decade, long-wavelength biomedical imaging is still suboptimal owing to the unsatisfactory materials properties of SWIR fluorophores. Taking advantage of organic dots based on an aggregation-induced emission luminogen (AIEgen), herein microscopic vasculature imaging of brain and tumor is reported in living mice in the SWIR spectral region. The long-wavelength emission of AIE dots with certain brightness facilitates resolving brain capillaries with high spatial resolution (≈3 µm) and deep penetration (800 µm). Owning to the deep penetration depth and real-time imaging capability, in vivo SWIR microscopic angiography exhibits superior resolution in monitoring blood-brain barrier damage in mouse brain, and visualizing enhanced permeability and retention effect in tumor sites. Furthermore, the AIE dots show good biocompatibility, and no noticeable abnormalities, inflammations or lesions are observed in the main organs of the mice. This work will inspire new insights on development of advanced SWIR techniques for biomedical imaging.

Aggregation‐Induced Dual‐Phosphorescence from Organic Molecules for Nondoped Light‐Emitting Diodes

“…Recently, luminescent materials, especially aggregation‐induced emission luminogens (AIEgens), have been a hotspot due to their wide applications in biosensors, information storage, and organic light‐emitting diodes (OLEDs) . The main benefit of aggregation‐induced emission (AIE) is the manifestation and augmentation of radiative excited states for organic molecular systems .…”

Quaternary Ammonium Salt Based NIR‐II Probes for In Vivo Imaging

“…Fluorescent chromophores are predominantly rigid planar molecules with π‐conjugated systems, which quickly lead to aggregation‐caused quenching (ACQ), responsible for severe ACQ effects in aqueous solution due to strong intermolecular π–π stacking interactions and therefore quench the excited state of the fluorophores . To solve this problem, Tang and his co‐workers have introduced the concept of aggregation induced emission (AIE) with strong fluorescence in dilute or aqueous solutions . Till now, several methods based on restraint of intramolecular rotations (RIR), restriction of intramolecular charge transfer (ICT), and limitation of twisted intramolecular charge transfer (TICT) have been developed to construct AIE systems .…”

Recent Advance in Near‐Infrared (NIR) Imaging Probes for Cancer Theranostics

“…[20] With several amino groups on the molecule, the peptide can be easily modified via the formation of amide bond. [22] Under 635 nm excitation, the mouse brain vasculature was identified at different depths from 50 to 800 μm. NIR II-emitted small molecule dyes for cancer theranostics.…”