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Among the various essential trace elements for living organisms, the copper (Cu2+) ions are the most important. However, Cu2+ ions are vital for the human body and are associated with necessary physiological processes; insufficient or excessiveness has many hazardous effects on our bodies. In the present contribution, strategically, we have introduced a julolidine-coupled azine-based, 9,9'-((1E,1'E)-hydrazine-1,2-diylidene bis(methanylylidene)) bis(1,2,3,5,6,7-hexahydropyrido [3,2,1-ij] quinolin-8-ol) (HDBQ) reversible chromo-fluorogenic probe for specific detection of Cu2+ ions. Probe HDBQ exhibits observable orange colorimetric change from yellow, which is visible to the naked eye in daylight. The highly green fluorescence HDBQ becomes a non-fluorescent one with the incorporation of Cu2+ ions. Interestingly, the colorimetric change and non-fluorescent HDBQ-Cu2+ complex reverse to the original HDBQ in the presence of ethylenediamine tetraacetic acid (EDTA). The detection and quantification limit of HDBQ towards the detection of Cu2+ ions is found to be in the µM range, which is much lower than the limit (31.5 µM) recommended by WHO. We have also performed a colorimetric and fluorometric paper-based test strips-based experiment employing HDBQ for real-time on-site detection of Cu2+ ions. Using the reversibility characteristics of HDBQ for the consecutive addition of Cu2+ and EDTA, we have established the INHIBIT molecular logic gate. The present report brings a precise and sensitive probe for the detection of Cu2+ ions in real environmental and biological samples. [ABSTRACT FROM AUTHOR]

Organic luminescent materials having photoluminescence in their solid state have become emerging trends in chemistry, materials science, and biology due to their versatile potential applications. In the present contribution, we have introduced some methylenebis(4,1-phenylene) electron donor–acceptor-based fashionable solid-state fluorescent molecules, MBA, MBB, and MBH, having exciting photoluminescence characteristics in their solid and aggregate states. Interestingly, all probes exhibited a compelling aggregation-induced enhanced emission (AIEE) phenomenon in aqueous media. The mechanistic aspects of solid-state brightness and AIEE behavior are elucidated by diverse spectroscopic, microscopic, and X-ray crystallographic analyses. Employing their intriguing AIEE characteristics, the water-suspended low dimensional particles have been employed as a sensor, demonstrating rapid sensitivity and brilliant selectivity towards the nitro-explosive compound picric acid (PA). The estimated limits of detection (LOD) and quantification (LOQ) reach as low as the μM to nM range in the aqueous medium. The fluorescent paper strip-based test kit experiment has been demonstrated for instant detection of PA through visual examination in the solid state, rendering the protocol quick, cost-effective, and appropriate for on-spot solid-state recognition. [ABSTRACT FROM AUTHOR]

Properly fusing various photophysical processes in a single chromo-fluorophore platform is crucial for developing a highly selective and sensitive chromo-fluorogenic probe to detect various target analytes. Moreover, deciphering the mechanistic approach for understanding the detection mechanism for any target analyte is paramount to facilitate the construction and development of new efficient probes for the selective detection and quantification of different target analytes. In this report, we introduce a phthalimide-based chromo-fluorogenic scaffold, DAID, fusing intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and excited-state intermolecular proton transfer (ESIPT) processes in a single molecular platform. DAID showed turn-on and ratiometric chromo-fluorogenic behaviors toward trivalent transition metal ions Al3+, Fe3+, and Cr3+ in a 20% (v/v) water–DMSO mixture. A visual colorimetric change was detected in the DAID solution by incorporating trivalent transition metal ions. A remarkable turn-on green color emission enhancement was noticed in the DAID solution in the presence of these trivalent ions. The limit of detection and limit of quantification for these trivalent transition metal ions were in the nM range and were superior to those of other methods reported in the literature. Time-resolved fluorescence-lifetime-decay, 1H-NMR titration, and high-resolution mass spectrometric analysis were carried out to elucidate the detailed mechanistic aspects to understand the detection mechanism for the identification of the trivalent transition metal ions employing the DAID probe. The successful demonstration of DAID for practical applications is encouraging for its further application in a variety of fields, fusing and deciphering the various photophysical processes in a single chromo-fluorophore platform, which would enable researchers to develop new efficient probes to selectively detect various target analytes. [ABSTRACT FROM AUTHOR]

A chromone‐coupled adenine‐based fluorogenic chemosensor (BD1) has been introduced for cascade detection of Zn2+ and HSO4−ions or Zn2+ and picric acid (PA) based on the fluorescence 'OFF‐ON‐OFF' mechanism. A momentous fluorescence improvement has been observed due to the accumulation of Zn2+ ions in the BD1 solution because of the formation of the Zn2+ chelated BD1 complex. A cyan color fluorescence enhancement is visible under the exposure of a 365 nm UV lamp, which is also manifested in the CIE diagram. The detection limit of our developed sensor BD1 and Zn2+−BD1 complex towards the identification of Zn2+ and HSO4− ions are in the nM and μM range, respectively, in the solution phase. Among the several explosive nitroaromatic compounds (NACs), only PA quenches the fluorescence of the Zn2+ chelated BD1 complex, and the nature of quenching is both static and dynamic. A paper strips‐based test kit experiment is performed for on‐spot identification of Zn2+ ions and PA. Based on these chemically encoded inputs and the fluorescence intensity as optical output, we have constructed an INHIBIT molecular logic circuit. The present report evokes a new approach for the development of new chemosensors from bioinspired materials such as adenine, a purine nucleobase. [ABSTRACT FROM AUTHOR]

During an immune response, activated leukocytes leave the circulation and enter the tissues. Leukocyte migration and extravasation is a multistep process involving the rolling and adhesion of leukocytes to the […]

We tested the hypothesis that microtubule (MT)-binding drugs could be therapeutically beneficial in tauopathies by functionally substituting for the MT-binding protein tau, which is sequestered into inclusions of human tauopathies and transgenic mouse models thereof. Transgenic mice were treated for 12 weeks with weekly i.p. injections of 10 or 25 mg/m² paclitaxel (Paxceed). Both doses restored fast axonal transport in spinal axons, wherein MT numbers and stable (detyrosinated) tubulins were increased, com- pared with sham treatment, and only Paxceed ameliorated motor impairments in tau transgenic mice. Thus, MT-stabilizing drugs could have therapeutic potential for treating neurodegenerative tauopathies by offsetting losses of tau function that result from the sequestration of this MT-stabilizing protein into filamentous inclusions. [ABSTRACT FROM AUTHOR]