Vinylpyridine- and vinylnitrobenzene-coating tetraphenylethenes: Aggregation-induced emission (AIE) behavior and mechanochromic property

Design and application of Cd2+ polypeptide fluorescent probes based on Aggregation Induced Emission (AIE)

Cadmium is a toxic heavy metal, which is both an environmental pollutant, and a threat to human health. A fluorescent probe was developed to detect Cd2+ selectively, sensitively, and quickly. This study reports the successful development of a polypeptide fluorescent probe TPE-HC (TPE-His-Pro-Gly-Cys) which selectively detects Cd2+ by Aggregation-Induced Emission effect. After fluorescence excitation, Cd2+ can be effectively detected based on the change of fluorescence intensity. The detection limit of Cd2+ in buffer solution was determined to be 151 nM (R2 = 0.9933). This probe exhibits high sensitivity, high cell permeabilit y, and low biological toxicity, and can perform live cell imaging under biological conditions. This study indicates that TPE-HC can detect Cd2+ in biological environments.

Recent progress in fluorescent probes for bacteria

Food fermentation, antibiotics, and pollutant degradation are closely related to bacteria. Bacteria play an irreplaceable role in life. However, some bacteria seriously threaten human health and cause large-scale infectious diseases. Therefore, there is a pressing need to develop strategies to accurately monitor bacteria. Technology based on molecular probes and fluorescence imaging is noninvasive, results in little damage, and has high specificity and sensitivity, so it has been widely applied in the detection of bacteria. In this review, we summarize the recent progress in bacterial detection using fluorescence. In particular, we generalize the mechanisms commonly used to design organic fluorescent probes for detecting and imaging bacteria. Moreover, a perspective regarding fluorescent probes for bacterial detection is discussed.

Donor triggered aggregation induced dual emission, mechanochromism and sensing of nitroaromatics in aqueous solution

The title paper describes the photophysics of a series of 2-benzylidenemalononitrile (RDC) derivatives, having donor- π - acceptor (D-π-A) architecture in solution, solid state and in hydrosol. Interestingly, it is observed that by tuning the electronic energy levels via changing donor strength, one can play with the emissive properties to the large extent; from non- fluorescent to fluorescent, to aggregation induced dual fluorescence, to aggregation induced enhanced emission (AIEE). The nature of aggregation is studied by Field Emission Scanning Electron Microscope (FESEM). This aggregation induced emission (AIE) in hydrosol is used to develop a thin layer chromatography (TLC) based simple, easy to use technique to identify the trinitrophenol in aqueous solution as well as can distinguish the three positional nitrophenol derivatives.

Cyanine-based fluorescent indicator for mercury ion and bioimaging application in living cells

A commercial cyanine dye IR-780 and a thioether-containing dicarboxylic acid ligand were used to construct the near-infrared fluorescent probe, which was used as a near-infrared fluorescent indicator for the determination of mercury ions in water and in living cells. This indicator displayed high specificity towards Hg²⁺ without any interference from other detecting species. Especially, the emission at 790 nm dramatically increased more than 25 times after interacting with Hg²⁺. The binding experiment showed that the indicator formed 1:1 complex with Hg²⁺. More, this indicator could be applied in the visualization of Hg²⁺ in living cells and measuring the Hg²⁺ concentration of tap-water sample.

Coordination-driven self-assembly of discrete supramolecular double-metallacycles

This review comprehensively summarizes the recent advances in the coordination-driven self-assembly of discrete supramolecular double-metallacycles.

Tetraphenylene-Coated Near-Infrared Benzoselenodiazole Dye: AIE Behavior, Mechanochromism, and Bioimaging

A D-π-A-π-D type of tetraphenylene-coating benzoselenodiazole fluorescence dye with near-infrared emission has been designed and constructed. This dye shows an obvious aggregation-induced-emission behavior. In the solid state, it exhibits a reversible mechanochromism with the changes of near-infrared emission. Furthermore, this dye can be used to track the lysosomes of living cells and images in vivo.

A Versatile Naphthalimide-Sulfonamide-Coated Tetraphenylethene: Aggregation-Induced Emission Behavior, Mechanochromism, and Tracking Glutathione in Living Cells

A tetraphenylethene (TPE) derivative substituted with a sulfonyl-based naphthalimide unit (TPE-Np) was designed and synthesized. Its optical properties in solution and in the solid state were investigated. Photophysical properties indicated that the target molecule, TPE-Np, possessed aggregation-induced emission (AIE) behavior, although the linkage between TPE and the naphthalimide unit was nonconjugated. Additionally, it exhibited an unexpected, highly reversible mechanochromism in the solid state, which was attributed to the change in manner of aggregation between crystalline and amorphous states. On the other hand, a solution of TPE-Np in a mixture of dimethyl sulfoxide/phosphate-buffered saline was capable of efficiently distinguishing glutathione (GSH) from cysteine and homocysteine in the presence of cetyltrimethylammonium bromide. Furthermore, the strategy of using poly(ethylene glycol)-polyethylenimine (PEG-PEI) nanogel as a carrier to cross-link TPE-Np to obtain a water-soluble PEG-PEI/TPE-Np nanoprobe greatly improved the biocompatibility, and this nanoprobe could be successfully applied in the visualization of GSH levels in living cells.

Aggregation-induced emission enhancement (AIEE)-active tetraphenylethene (TPE)-based chemosensor for Hg2+ with solvatochromism and cell imaging characteristics

An aggregation-induced emission enhancement (AIEE)-active fluorescent sensor based on a tetraphenylethene (TPE) unit has been successfully designed and synthesized. Interestingly, the luminogen could detect Hg²⁺ with high selectivity in an acetonitrile solution without interference from other competitive metal ions, and the detection limit was 7.46 × 10⁻⁶ mol L⁻¹. Furthermore, the luminogen also showed interesting solvatochromic behavior and superior cell imaging performance.

A TPE-based AIEE-active fluorescent sensor for Hg²⁺ was synthesized. Furthermore, it showed solvatochromism and cell imaging characteristics.