Trace Level Recognition of Zn2+ and Cd2+ by Biocompatible Chemosensor inside Androecium, Diagnosis of Pick's Disease from Urine and Biomimetic β-Cell Exocytosis.

Abstract

Two chemosensors with varying substitution have been synthesized for selective detection of d10 metal ion analyte Zn2+ and Cd2+ by fluorometric method from aqueous medium at very low limit of detection. Density functional theory (DFT)-based Loewdin spin population analysis reveals that methoxy-substituted chemosensor is much stronger donor than bromo-substituted chemosensor. Eventually, bromo and methoxy substituted chemosensors are moderate and strong donor, respectively, toward selective detection of Cd2+ and Zn2+ by luminescence induced phenomenon (blue for Cd2+ and cyan for Zn2+). The mechanism of sensing could be explained by PET-CHEF-C = N isomerization-ILCT pathway. 1H NMR, ESI-MS and FT-IR has been carried out in order to explore the selective ion sensing mechanism. Intracellular detection of Zn2+ and Cd2+ has been carried out inside androecium (filament and pollens) of Tecoma Stans. Extracellular detection of Zn2+ for yeast cells represents the bio mimetic model experiments toward β-cells exocytosis as a marker of diabetes mellitus. The unprecedented and novel feature of the present biocompatible chemosensor is its application as biosensor to detect in vivo Zn2+ from human urine specimen which could be a next generation diagnostic tool for Pick's disease.