Near-infrared fluorescent probe to track Cys in plant roots under heavy metal hazards and its application in cells and zebrafish.

Heavy metals, including Hg2+, Cr6+ and Cd2+, have always been a major issue in environmental pollution, leading to abnormal changes in the levels of biologically active molecules including Cys in plants, seriously affecting all aspects of the growth and development of plants. This makes it essential to develop a simple and practical method to study the potential impact of heavy metals on plants. In this paper, our research group has developed near-infrared fluorescent probe WRM-S, which has the advantages of fast response, sensitivity to Cys, and successfully applying it to cells and zebrafish. Moreover, it combined the close relationship between heavy metal stress on plants and Cys, using Cys as the detection target, monitoring the internal environment changes of two plants under Hg2+, Cr6+, and Cd2+ stress in the environment, and then conducting 3D imaging. The results indicated that the probe has strong penetration ability in plant tissues, and revealed abnormal changes in plant Cys levels caused by heavy metal stress-induced cellular oxidative stress or cytotoxicity. Thus, the in-situ imaging detection of this probe provides a direction for the physiological dynamics research of plant environmental stress.

Near-Infrared Fluorescent Probe for Imaging Upregulated Hydrogen Sulfide Levels in Rice under Salt and Drought Stress.

Hydrogen sulfide (H2S) is a hazardous gas found in living organisms and is directly tied to our daily lives. Recent studies show that it plays a significant role in plant growth, development, and response to environmental stresses. However, few of the reported near-infrared (NIR) fluorescent probes have been applied to rice and deeply investigated the influence of the external environment on the biological molecules in its internal environment. Therefore, our team created BSZ-H2S, which has the advantage of an emission wavelength of up to 720 nm with fast response, successfully applying it to cell and zebrafish imaging. More importantly, the probe detected H2S in rice roots by in situ imaging in a facile manner and verified the existence of an upregulation process of H2S in response to salt and drought stress. This work provides a concept for the intervention of external stresses in rice culture.

Sensitive and Visual Detection of Phosgene by a TICT-Based BODIPY Dye with 8-(o-Hydroxy)aniline as the Active Site.

Phosgene and its substitutes (diphosgene and triphosgene) are widely utilized as chemical industrial materials and chemical warfare agents and pose a threat to public health and environmental safety due to their extreme toxicity. Research efforts have been directed to develop selective and sensitive detection methods for phosgene and its substitutes. In this paper, we have prepared two BODIPY-based fluorescent probes, o-Pah and o-Pha, which are two isomers with different active sites, ortho-aminohydroxy (3',4' or 4',3') phenyls at meso position of BODIPY, and compared their sensing performance toward triphosgene. The probe with o-(4'-amino-3'-hydroxyl), o-Pha, exhibits better sensing performance over the o-(3'-amino-4'-hydroxyl), o-Pah, for instance, a lower limit of detection (LOD) (0.34 nm vs. 1.2 nm), and more rapid response (10 s vs. 200 s). Furthermore, based on the above comparative studies, a red-fluorescence probe o-Phae has been constructed through extending 3,5-conjugation of o-Pha. The probe o-Phae displays rapid response (60 s), high sensitivity to triphosgene (LOD=0.88 nm), and high selectivity for triphosgene over relevant analytes including nitric oxide. Finally, a facile test strip for phosgene was fabricated by immobilizing o-Phae in a polyethylene oxide membrane for sensitive (<2 ppm) and selective detection of phosgene in the gas phase.

Synthesis of Oxadiazolones with Hydrazides: The Mechanism and the Sensing Application as Sensitive, Rapid, and Visual Fluorescent Sensors for Phosgene.

The reaction of hydrazides with triphosgene in the presence of triethylamine is a facile method to construct various oxadiazolones. Utilizing this reaction, a new class of colorimetric and fluorogenic phosgene chemosensors were developed with the BODIPY as fluorophore, five BODIPY-based hydrazides, which exhibited highly effective reactions with phosgene. The mechanism was updated. Finally, the test paper with a hydrazide was fabricated for facile, selective, and visual detection of phosgene gas.

A turn-on fluorescence sensor for the highly selective detection of Al3+ based on diarylethene and its application on test strips.

A novel turn-on fluorescent sensor for Al3+ based on photochromic diarylethene with a 2-hydroxybenzhydrazide unit has been successfully designed and synthesized. The photochromic and fluorescent characteristics were studied methodically in methanol under irradiation using UV/vis light and induced by Al3+/EDTA. This fluorescent sensor was highly selective toward Al3+ with an obvious fluorescent color change from dark blue to blue. The Job's plot and mass spectrometry (MS) analysis indicate a binding stoichiometry of 1 : 1 between the fluorescent sensor and Al3+. Moreover, a test strip containing this fluorescent sensor was prepared to allow for the easy detection of Al3+ in water. Finally, a logic circuit was designed using four input signals (In1: UV; In2: vis; In3: Al3+; In4: EDTA) and one output signal.

A highly selective and sensitive fluorescent sensor for relay recognition of Zn2+ and HSO4-/H2PO4- with "on-off" fluorescent responses.

A simple and effective fluorescent sensor bearing pyridine units was designed and synthesized. The sensor can detect Zn2+ with high selectivity accompanied by a distinct fluorescence turn-on response, inducing the fluorescent color markedly changed from darkness to bright green. The limit of detection (LOD) was calculated as 8.56 × 10-9 M with a good linearity (R = 0.95943). In addition, the chelate of sensor with Zn2+ can further recognize H2PO4-/HSO4- with notable fluorescence quenching behaviors over other anions and the LODs were as low as 3.44 × 10-6 M (R = 0.99762) and 3.84 × 10-6 M (R = 0.99315), respectively.

Selective and Real-Time Detection of Nitric Oxide by a Two-Photon Fluorescent Probe in Live Cells and Tissue Slices.

Nitric oxide (NO) is an important signaling molecule involved in many physiological and pathological processes. To understand these NO-mediated processes, it is a key to develop rapid and specific detection methods for NO. In the past 2 decades, numerous excellent fluorescent probes for NO have been designed; however, it still remains limitations such as slow response, low selectivity, and short excitation wavelength (<600 nm). In this Article, a two-photon fluorescent probe, NO-QA5, has been developed with 3-dimethylaminophenyl linking at the 6-position of 5-aminoquinoline as both the active site and prefluorophore for detection of NO. The nonfluorescent NO-QA5 can fast react with NO via a diazonium intermediate to generate two azoic regioisomers, one of which exhibits intramolecular charge transfer (ICT) emission, and two-photon absorption behavior (Î´Φ = 57 GM), giving a turn-on fluorescence rapid response. The sensing reaction is pH-insensitive in the range of 6-11 and highly selective and well sensitive (LOD = 15 nM), possible undergoing the same intermediate diazonium with the reaction under diazotization condition (NaNO2/HCl). Also, as a nitrite fluorescent probe NO-QA5 exhibits highly sensitive (LOD = 7 nM). Therefore, NO-QA5 can serve as a dual functional fluorescent probe for NO and NO2-. Furthermore, NO-QA5 as a specific imaging agent has been demonstrated by achieving both exogenous and endogenous detections of NO in living cells under both one- and two-photon excitation and high resolution in tissue slices under two-photon excitation.