The Biological Applications of Two Aggregation‐Induced Emission Luminogens

Abstract

Fluorescence imaging, as a commonly used scientific tool, is widely applied in various biomedical and material structures through visualization technology. Highly selective and sensitive luminescent biological probes, as well as those with good water solubility, are urgently needed for biomedical research. In contrast to the traditional aggregation‐caused quenching of fluorescence, in the unique phenomenon of aggregation‐induced emission (AIE), the individual luminogens have extremely weak or no emissivity because they each have free intramolecular motion; however, when they form aggregates, these components immediately “light up”. Since the discovery of “turn‐on” mechanism, researchers have been studying and applying AIE in a variety of fields to develop more sensitive, selective, and efficient strategies for the AIE dyes. There are numerous advantages to the use of AIE‐based methods, including low background interference, strong contrast, high performance in intracellular imaging, and the ability for long‐term monitoring in vivo. In this review, two typical examples of AIEgens, TPE‐Cy and TPE‐Ph‐In, are described, including their structure properties and applications. Recent progress in the biological applications is mainly focused on. Undoubtedly, in the near future, an increasing number of encouraging and practical ideas will promote the development of more AIEgens for broad use in biomedical applications.

Probing the Interactions Between Anthanthrene Derivatives and Bovine Serum Albumin (BSA) Through Aggregation Induced Emission

“…The design of such AIE materials often required careful molecular structural tailoring and modification, especially to achieve the emission wavelengths from red to NIR region. For instance, tetrazolate‐functionalized TPE derivatives with excellent AIE properties have been studied for the selective and quantitative detection of HSA [46,52] . Recently, we have demonstrated the AIE properties of super extended anthanthrene materials, derived from anthanthrone dye [53] .…”

“…For the past decade, the AIE property has been widely used as facile and efficient sensory tool to identity the binding events, translating into the detectable signals during the aggregation process. This phenomenon has been exploited in various applications including display technologies, luminescent sensors, biotherapeutics, biosensing and cell imaging [45–51] . The design of such AIE materials often required careful molecular structural tailoring and modification, especially to achieve the emission wavelengths from red to NIR region.…”

Optical molecular imaging and theranostics in neurological diseases based on aggregation-induced emission luminogens

“…In fact, AIE processes have been reported to be also associated with other intramolecular processes such as J-aggregate formation (JAF), twisted intramolecular charge transfer (TICT), and excited-state intramolecular proton transfer (ESIPT) [18,19]. AIEgens not only inherit advantages from conventional organic fluorogens like simple operations, high-fluorescence quantum yield, and good biocompatibility, but also exhibit better photostability and stronger emission with a large Stokes shift, which help to resist photobleaching and have a good potential for biomedical investigations in the complicated environment [20,21]. Furthermore, AIEgens are endowed with excellent specific and sensitive targeting and therapeutic ability based on the molecular structure and optical characteristics to achieve image-guided theranostics, which can exert phototherapy including photodynamic therapy (PDT) and photothermal therapy (PTT) in the targeted sites [22][23][24][25][26].…”

Recent Advances in Aggregation-Induced Emission Active Materials for Sensing of Biologically Important Molecules and Drug Delivery System

“…There are other non-radiative decay processes such as restricted intramolecular vibration and rotational relaxation responsible in the AIE process. Many research groups have reported AIE-active molecules that can be used for chemical sensors [ 18 , 19 , 20 ]. Among them, hexaphenylsilole (HPS) is the common example of the AIE active molecule which exhibits enhancement in fluorescence in an aggregate state.…”