The synthesis of Cu nanoclusters and their dual mode colorimetric and fluorescent sensing for 2, 4-dinitrophenol

Abstract

Herein, we have reported a facile one-pot strategy to synthesize fluorescent Cu nanclusters (Cu NCs) by using ʟ-histidine as stabilizer, and ascorbic acid as reducing agent. Cu NCs are stable, water-dispersible, and emit bright cyan emission with a quantum yield 26.08%. The Cu NCs can be employed as colorimetric and fluorimetric dual-mode detector, exhibiting excellent selectivity and sensitivity for detecting 2,4-dinitrophenol (DNP) specifically. Notably, Cu NCs were a sensitive sensor, which had speciality to detect DNP in range of linearity from 0.01 to 0.15 mM with a discernable limit as low as 3.96 μM. The mechanism of efficiently selective detection of DNP by Cu NCs was analyzed by UV absorption, fluorescence decay spectrum, and the performance of 'turn off' towards DNP was determined as the inner filter effect and static quenching effect. Further, the environmental tolerance of the Cu NCs probe was estimated by using the different natural water samples, demonstrating its great promise in the field of DNP monitoring and water sample analysis.

Challenges and Opportunities of Using Fluorescent Metal Nanocluster-Based Colorimetric Assays in Medicine

“…Notably, a new Meisenheimer complex formation through hydrogen bonding, acid–base pairing, and electrostatic interactions caused a yellow color change in the reaction solution from colorless. The recoveries in river water and tap water were found to be 91.2%–102% and 105.8%–114.7%, respectively (Figure D) . In another study, M. Fu et al utilized His-AuNCs, which can catalyze the oxidation of colorless TMB for the detection of iodide (I – ) and Hg 2+ .…”

“…Copyright 2021 Royal Society of Chemistry. (D) Amino acid: (a) the synthesis of l -His-CuNCs and (b) DNP recognition by the inner filter effect (IFE) fluorescence mechanism (turn-off) and a new Meisenheimer complex formation allowing a color change to yellow solution; 69 adapted with permission from ref ( 69 ). Copyright 2021 IOP Publishing Ltd. (E) Nucleic acid: (a) the synthesis of NCs by cytosine-rich DNA in the presence of strong reducing agent (NaBH 4 ) and (b) its application for detection of H 2 O 2 and glucose by peroxidase-like activity of DNA-Cu/AgNCs; 73 adapted with permission from ref ( 73 ).…”

BSA-Capped Dual-Emissive Silver Nanoclusters for Detection of IO4– and Cu2+ Ions

“…Metal nanoclusters (MNCs) possessing inherent intriguing features, viz., molecule-like discrete energy levels, ultrasmall size, and remarkable fluorescence (Fl), continue gaining attention among researchers. − Their exceptional inherent properties render them an extensive platform for offering various applications like sensing toxic metal ions − and hazardous molecules, , bioimaging, photodynamic theory, catalysis, and optoelectronics . MNCs, particularly with red or near-infrared (NIR) emission, possess remarkable advantages in contrast to lower wavelength emitting MNCs due to their beneficial properties like deep cell penetrating power, minimizing the possibility of light scattering, and bypassing autofluorescence, − augmenting their utilization for various applications ranging from sensing of environmental contaminants to biologically hazardous molecules. − MNCs capped by proteins offer excellent biocompatibility and optical stability. − Following the first report of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs), several other proteins, e.g., lysozyme (LYS), ovalbumin, insulin, pea protein, and pepsin, have been utilized for capping many other MNCs.…”

A novel fluorescent nanoprobe for sensitive detection of 6-thioguanine in human serum based on Cu/Ag nanoclusters

“…CuNCs exhibit excellent properties, including large Stokes shifts, good water solubility, excellent catalytic activity, high biocompatibility and strong fluorescence. As a result, they have been widely used in sensing, 25,26 bioimaging 27 and chemical catalysis. 28 Thiols are widely used as a reducing agent and stabilizing agent for the preparation of CuNCs.…”