Aggregation-Induced Fluorogens in Bio-Detection, Tumor Imaging, and Therapy: A Review

Abstract

Aggregation-induced emission (AIE) produce strong, stable fluorescence upon aggregation, thus it is pushing a new frontier in bio-detection, cell imaging and other biomedical applications. In this review, we summarize the recent developments of AIEgens about design strategy, bio-detection, cell imaging, tumor imaging, vascular imaging and image-guided tumor therapy. We especially highlight a section on the microfluidic approach to synthesize AIE nanoparticles (NPs) and current challenges and promising prospects of AIE NPs.

Aggregation Turns BODIPY Fluorophores into Photosensitizers: Reversibly Switching Intersystem Crossing On and Off for Smart Photodynamic Therapy

“…It is commonly known that aggregation-induced-emission (AIE) represents an effective approach to enhance fluorescnece upon aggregation. [69][70] In recent years, several groups have also employed AIE strategy to generate ROS in aggregation states. [71][72][73][74][75][76] However, it differs from our present strategy.…”

Molecular Engineering of Noncovalent Dimerization

“…Organic molecular-based functional materials are recognized as crucial drivers of emerging technologies for their rapid development and applications as dyes and semiconductors in optoelectronics, , as probes and medicine in theragnostics, , as active intermediates and catalysts in chemical reactions, , as switches and rotors in molecular machines, − etc. To customize a molecular-based system toward desired functions, it typically requires careful consideration of two aspects: (i) the intrinsic features of a single molecule species determined by its atomic arrangement and connection; and (ii) the coherent features of molecular ensembles determined by the interplay among them .…”

Photosensitizer Encryption with Aggregation Enhanced Singlet Oxygen Production

“…A significant current disadvantage in the implementation of photosensitizers based on conjugated chromophore molecules is their tendency to aggregate in aqueous media because of either general insolubility or enhancement of hydrophobic intermolecular interactions . Aggregation typically causes deactivation of photosensitizers in vivo even if excellent 1 O 2 generation properties are found in vitro . − To ameliorate for aggregation-induced effects, various nanoarchitecturing strategies, as well as numerous macroscale architectures, ,− have been proposed for the sequestration of the photosensitizer moiety to suppress deactivation. , These nanoscale architectures include the encapsulation of photosensitizers in lipid particles or colloids, , incorporation into dendrimeric , or polymeric , architectures, or inclusion of the photosensitizers in hybrid core–shell nanoparticles − or porous nanomaterials. − Multifunctional self-assembled nanostructures have also been investigated although these approaches have often involved highly technical multistep syntheses leading to complex nanosystems of limited stability or efficacy. , Conversely, compared to aggregation-induced/enhanced emission (AIEE), aggregation-induced/enhanced 1 O 2 generation by photosensitizers has hardly been demonstrated for PDT applications. − That being said, there have been several recently reported examples utilizing AIEE photosensitizers in vitro and in vivo ; , however, despite the utilization of AIEE agents, surfactants to stabilize and/or ensure biocompatibility are still required in some cases. − …”