An Intramolecular Charge Transfer and Aggregation Induced Emission Enhancement Fluorescent Probe Based on 2‐Phenyl‐1,2,3‐triazole for Highly Selective and Sensitive Detection of Homocysteine and Its Application in Living Cells

Highly selective and sensitive fluorescent probe possessing AIEE and ICT properties for rapid detection of Pb2+ in aqueous medium and its applications in living cells

In this paper, a novel rapid, highly selective and sensitive Pb²⁺ fluorescent probe (E)-N'-((2-(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl)-2H-1,2,3-triazol-4-yl)methylene) (DBTBH) was synthesized. The probe DBTBH not only exhibited more excellent selectivity and sensitivity to Pb²⁺ detection compared with other analytes (include metal ions and anions) in H₂ O:THF solution (v:v = 9:1, 10 mM Tris-HCl, 1 mM KI, pH 7.4), but also had excellent optical properties such as aggregation-induced emission enhancement (AIEE) and intramolecular charge transfer (ICT). Detection limit of the probe DBTBH towards Pb²⁺ was 4.49 × 10^-8  M. The possible mechanism was verified by ¹ H NMR titration and HR-MS. Furthermore, the successful detection of Pb²⁺ by DBTBH in real water samples and HeLa cells indicated that DBTBH has great potential for selective recognition of Pb²⁺ in the natural environment and biological systems. These findings will provide a promising new idea for designing better Pb²⁺ fluorescent probes in the future.

Real-Time Visualization and Monitoring of Physiological Dynamics by Aggregation-Induced Emission Luminogens (AIEgens)

Physiological dynamics in living cells and tissues are crucial for maintenance and regulation of their normal activities and functionalities. Tiny fluctuations in physiological microenvironments can leverage significant influences on cell growth, metabolism, differentiation, and apoptosis as well as disease evolution. Fluorescence imaging based on aggregation-induced emission luminogens (AIEgens) exhibits superior advantages in real-time sensing and monitoring of the physiological dynamics in living systems, including its unique properties such as high sensitivity and rapid response, flexible molecular design, and versatile nano- to mesostructural fabrication. The introduction of canonic AIEgens with long-wavelength, near-infrared, or microwave emission, persistent luminescence, and diversified excitation source (e.g., chemo- or bioluminescence) offers researchers a tool to evaluate the resulting molecules with excellent performance in response to subtle fluctuations in bioactivities with broader dimensionalities and deeper hierarchies.

Recent Progress of Glutathione (GSH) Specific Fluorescent Probes: Molecular Design, Photophysical Property, Recognition Mechanism and Bioimaging

The selective detection of glutathione (GSH) in vitro and in vivo has attracted great attentions, credited to its important role in life activities and association with a series of diseases. Among all kinds of analytical techniques, the fluorescent probe for GSH detection become prevalent recently because of its ease of operation, high temporal-spatial resolution, visualization and noninvasiveness, etc. The special structural features of GSH, such as the nucleophilicity of sulfhydryl group, the concerted reaction ability of amino group, the negative charged nature, the latent hydrogen bonding ability along with its flexible molecular chain, are all potent factors to be employed to design the specific fluorescent probe for GSH and discriminate it from other bio-species including its analogues cysteine (Cys) and homocysteine (Hcy). This paper reviewed the studies in the last 3 years and was organized based on the reaction mechanism of each probe. According to the reactivity of GSH, various recognition mechanisms including Michael addition, nucleophilic aromatic substitution, ordinary nucleophilic substitution, multi-site reaction, and other unique reactions have been utilized to construct the GSH specific fluorescent probes, and the molecular design strategy, photophysical property, recognition mechanism, and bioimaging application of each reported probe were all discussed here systematically. Great progress has been made in this area, and we believe the analyses and summarization of these excellent studies would provide valuable message and inspiration to researchers to advance the research toward clinic applications.