Esterase-Mediated Highly Fluorescent Gold Nanoclusters and Their Use in Ultrasensitive Detection of Mercury: Synthetic and Mechanistic Aspects

Abstract

The fast, accurate, and ultrasensitive detection of toxic mercury in real water samples is still challenging without the use of expensive sophisticated instruments. Herein, highly fluorescent gold nanoclusters (AuNCs) were synthesized using a newer protein templet, esterase (EST). The EST-AuNCs consisted of ∼25 Au atoms in the nanocluster having ∼2 nm size. EST-AuNCs were found to be highly stable in aqueous buffer with a wide range of pH (pH 4–12) and were also stable in powdered form. The fluorescence quantum yield of EST-AuNCs in deionized water was 6.2% which had increased to 7.8% upon the addition of 1 M NaCl (an increase of 23%). The EST-AuNCs selectively sense the toxic Hg 2+ ions with higher sensitivity (limit of detection; 0.88 nM) with the linear range 1–30 nM. The test strips for rapid sensing of Hg 2+ in real water samples were developed on the polymeric surface. The validation of sensing ability of EST-AuNCs suggested 94–98% recovery with linearity. Moreover, because of the widely reported applications of EST, the developed EST-AuNCs could also be used for another sensing, catalytic, and biomedical applications.

Microwave-Assisted Synthesis of Red Emitting Copper Nanoclusters Using Trypsin as a Ligand for Sensing of Pb2+ And Hg2+ Ions in Water and Tobacco Samples

“…The LODs for Pb 2+ and Hg 2+ are 14.32 nM and 56.81 nM, respectively. In addition, the LODs of the proposed technique have lower values as compared to that of other reported methods for the detection of Pb 2+ and Hg 2+ ions [25][26][27][28][44][45][46][47][48][49][50][51][52][53][54] (Table I).…”

Porphyrin Functionalized Gelatin Nanoparticle-Based Biodegradable Phototheranostics: Potential Tools for Antimicrobial Photodynamic Therapy

“…Herein, we observed a sudden increase in the tABpor fluorescence after the incorporation of it into the GNPs. The most plausible reason behind this might be the restriction in the nonradiative decay electrons due to the groups present in the gelatin matrix . This restriction led these electrons to their excited states for a longer time and further to the ground state as radiative electrons with fluorescence.…”

Recent advances in the visual detection of ions and molecules based on gold and silver nanoclusters

“…The color of the solution varied from red to blue in various concentrations of Hg 2+ . 32 The method visually detected Hg 2+ as low as 0.88 nM and the LOD has been greatly reduced. Inspired by the previous work, our group proposed a new method based on the ratiometric and visual detection of Hg 2+ using bovine serum albumin (BSA)-protected Au/AgNCs.…”