Ratiometric sensing of Zn2+ with a new benzothiazole-based fluorescent sensor and living cell imaging

A new fluorescent probe, 3-(Benzo[d]thiazol-2-yl)-5-bromosalicylaldehyde-4N-phenyl thiosemicarbazone (BTT) for ratiometric sensing of Zn2+ ions in methanol / HEPES buffer solution (3 : 2, pH = 7.4) is reported in this paper....

Fluorescence Recognition of Al(III) Ions by a New Chemosensor Based E-4-((1-(10H-Phenothiazin-2-yl)ethylidene)amino)-N-(pyrimindin-2-yl)benzenesulfonamide

A novel Schiff base derivative E-4-((1-(10H-phenothiazin-2-yl) ethylidene)amino)-N-(pyrimindin-2- yl)benzenesulfonamide (BT) was synthesized and characterized by 1H & 13C NMR, FT-IR and mass spectrometry. Compound BT acts as a detector for Al3+ in ethanol/water HEPES buffer solution (5 mM, pH 7.4, v/v 1:4) at room temperature. The fluorescence intensity observed at 516 nm was increased due to Al3+ ion present with a fluorescence response “turn-on” process, when excited at 290 nm. This shows compound BT is coordinated to Al3+ ion through the NH group and C=NH of the Schiff base blocking the photoinduced transfer (PET) and chelation induced enhanced fluorescence (CHEF) process, to increase the fluorescence intensity of BT. The detection limit of BT was in a micro-molar range for Al3+ ion, confirming high selectivity and sensitivity of BT. The BT-Al3+ ion binding mode and the recognition mechanism of chemosensor were explored by EDTA titration, Job’s plot, Mass and FT-IR analysis. The theoretical support was established by DFT calculations.

A MODIFIED METHOD FOR STUDYING THE GLYCOXIDATION REACTION

The article considers a particular model of the glycation reaction, called glycoxidation and characterized by a significant involvement of oxidative reactions and the participation of transition metals. The enhancement of oxidative processes, which makes it possible to identify the reaction as glyoxidation, was realized by introducing copper (II) cations (CuSO 4 * 5H 2 O) into the reaction medium in a form accessible for interaction with the reaction participants. The main reagents in the glycoxidation reaction, in addition to CuSO 4 *5H 2 O are bovine serum albumin (1 g/l), glucose (0,5 M), HEPES buffer solution (24 g/l) dissolved in deionized water. The conditions have been selected under which the glycoxidation reaction linearly depends on the concentration of copper (II), which makes the cation activity a sensitive target when monitoring the reaction. The dependence of the reaction on the concentration of CuSO 4 * 5H 2 O under the presented experimental conditions has been confirmed experimentally and mathematically. An analytical range of concentrations of CuSO 4 *5H 2 O has been established, in which a linear dependence of AGE formation on concentration is observed. For the concentration of CuSO 4 *5H 2 O, which produces the greatest potentiating effect on the AGE formation (10 mg/l), the procedure was validated by the indices of internal laboratory reproducibility and convergence. The technique is of interest for investigation of the antiglycoxidative activity of novel compounds.

A selective fluorescent probe for the detection of Cd2+ in different buffer solutions and water

A fluorescent probe NHQ, which exhibited excellent selectivity toward Cd2+ in different buffer solutions such as Tris-HCl buffer solution, HEPES buffer solution, and PBS buffer solution, and even in water, was developed.

An Aptamer-Modified Nanogold Method for the Determination of Trace Ag+ Using Resonance Rayleigh Scattering as Detection Technique

Aptamer was modified the gold nanoparticle (AuNP) to form stable aptamer-AuNP probe that was not gathered in the pH 7.2 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) buffer solution and in the presence of NaCl. The Ag+ react with the aptamer-AuNP probe to fold a hairpin structure complex of Ag+-aptamer and release AuNPs that were aggregated to large particles, which lead to resonance Rayleigh scattering (RRS) peak at 596 nm enhancement. The enhanced value ΔI596nm is linear to Ag + concentration in the range of 6.7×10-8-1.33×10-6 mol/L. Thus, a new RRS methods were proposed for detection of Ag+, with high sensitivity, good selectivity and simplicity.