Designed Synthesis of Fluorescence 'Turn-on' Dual Sensor for Selective Detection of Al3+ and Zn2+ in Water

Fluorescent Turn-On Anthracene-Based Aluminum(III) Sensor for a Therapeutic Study in Alzheimer's Disease Model of Drosophila

A new anthracene-based probe (E)-N'-(1-(anthracen-9-yl)ethylidene)-2-hydroxybenzohydrazide (AHB) has been efficiently synthesized and characterized by various spectroscopic methods. It exhibits extremely selective and sensitive fluorometric sensing of Al3+ ions with a large enhancement in the fluorescent intensity due to the restricted photoinduced electron transfer (PET) mechanism with a chelation-enhanced fluorescence (CHEF) effect. The AHB-Al3+ complex shows a remarkably low limit of detection at 0.498 nM. The binding mechanism has been proposed based on Job's plot, 1H NMR titration, Fourier transform infrared (FT-IR), high-resolution mass spectrometry (HRMS), and density functional theory (DFT) studies. The chemosensor is reusable and reversible in the presence of ctDNA. The practical usability of the fluorosensor has been established by a test strip kit. Further, the therapeutic potential of AHB against Al3+ ion-induced tau protein toxicity has been tested in the eye of Alzheimer's disease (AD) model of Drosophila via metal chelation therapy. AHB shows great therapeutic potential with 53.3% rescue in the eye phenotype. The in vivo interaction study of AHB with Al3+ in the gut tissue of Drosophila confirms its sensing efficiency in the biological environment. A detailed comparison table included evaluates the effectiveness of AHB.

Anthracene scaffold as highly selective chemosensor for Al3+ and its AIEE activity

Fluorescent chemosensor, 3-(Anthracen-2-yliminomethyl)-benzene-1,2-diol (ANB) has been synthesized by one-step condensation of 2-aminoanthracene and 2,3-dihydroxybenzaldehyde and characterized using ¹H-NMR, FT-IR and Mass spectroscopic techniques. The probe ANB was found to be an efficient 'turn-on' fluorescence chemosensor for the selective detection of Al³⁺ ion over other metal ions in an aqueous solution. The chemosensor exhibits ~ 27-fold enhancement of emission intensity in presence of Al³⁺ ion. Fluorescence quantum values for ANB and (Al³⁺-ANB)-complex are 0.004 and 0.097, respectively. In addition, the binding constant and the limit of detection were found to be 1.22 × 10⁴ M^-1 and 0.391 µM, respectively. The chemosensor ANB binds to Al³⁺ ions in 2:1 stoichiometric ratio which was supported by Job's plot, ¹H-NMR titration and florescence titration. Fluorescence reversibility of the sensor complex was well established by adding EDTA in the same condition and a molecular INHIBIT logic gate was fabricated using this reversible nature of the sensor complex. Additionally, the chemosensor ANB shows a novel aggregation-induced enhanced emission phenomenon, where the aggregate hydrosol of ANB shows enhance emission intensity.

a Versatile Schiff Base Chemosensor for the Determination of Trace Co2+, Ni2+, Cu2+, and Zn2+ in the Water and Its Bioimaging Applications

In this work, a simple and versatile Schiff base chemosensor (L) was developed for the detection of four adjacent row 4 metal ions (Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺) through colorimetric or fluorescent analyses. L could recognize the target ions in solutions containing a wide range of other cations and anions. The recognition mechanisms were verified with a Job's plot, HR-MS assays, and ¹H NMR titration experiments. Then, L was employed to develop colorimetric test strips and TLC plates for Co²⁺. Meanwhile, L was capable of quantitatively measuring the amount of target ions in tap water and river water samples. Notably, L was used for imaging Zn²⁺ in HepG2 cells, zebrafish, and tumor-bearing mice, which demonstrated its potential biological applications. Therefore, L can probably serve as a versatile tool for the detection of the target metal ions in environmental and biological applications.