Colorimetric and ultra-sensitive fluorescence resonance energy transfer determination of H2O2 and glucose by multi-functional Au nanoclusters

Abstract

Ultra-sensitive colorimetric determination of H2O2 is accomplished based on the intrinsic peroxidase-like activity of Au nanoclusters (AuNCs) stabilized by glutathione (GSH). The color change of 3,3,5,5-tetramethylbenzidine (TMB) catalyzed by AuNCs offers an indirect method to measure glucose. This sensing platform makes use of a dual optical signal change, including the color change in an aqueous solution under visible light illumination and an ultra-sensitive fluorescent assay arising from efficient fluorescence resonance energy transfer (FRET) between the AuNCs and oxidized TMB. The detection limits of H2O2 and glucose are 4.9 × 10(-13) M and 1.0 × 10(-11) M, respectively. In addition, enhanced fluorescence is observed from the AuNCs due to the use of ethanol which produces clear changes in the quantum yield and lifetime of the AuNCs. The quantum yield of AuNCs is enhanced from ∼12.5% as an isolated fluorophore to 38.9% in an AuNCs-ethanol complex. The enhanced fluorescence lowers the detection limits of H2O2 and glucose by 2 orders of magnitude compared to those attained from the original AuNCs.

Multiplex sensor for detection of different metal ions based on on–off of fluorescent gold nanoclusters

“…As previous works reported [36,37], the quenching of fluorescent nanoclusters is a result of metal ions in close proximity of the surface of nanoclusters or even the adsorption of metal ions on the surface. Due to the high probability of the coexistence of these metal ions, the problem here is also obvious: with the coexistence of the three kinds of cations, it is difficult to tell the source of the quenching.…”

New Nanomaterials and Luminescent Optical Sensors for Detection of Hydrogen Peroxide

“…The same regeneration scheme could be useful for [15] where a reductant would need to restore the original size of the HRP-Au NCs. A similar scheme could work for [14] and [22] where repetitive addition of TMB would be required for regeneration. For [21] a complete ligand exchange at the Tb 3+ -ions would be required to substitute the carboxyphenyl-4-oxo anions with carboxyphenyl-4-boronic acid groups.…”

“…For example, Lim et al [13] synthesized fluorescein isothiocyanate (FITC)-doped silica nanoparticles (FSNs) with AuNP seeds. Ultra-sensitive colorimetric determination of H2O2 and glucose based on the intrinsic peroxidaselike activity of Au nanoclusters (AuNCs) stabilized by glutathione (GSH) was proposed by Zhao et al [14]. The analyte concentrations are monitored indirectly via the color change of 3,3,5,5-tetramethylbenzidine (TMB) upon oxidation by H2O2 catalyzed by AuNCs.…”

“…After a further mixing loop, the resulting product stream would be measured via fluorescence spectroscopy. FIA-sensors could also be designed for the nanomaterials presented in [12,14,15,[20][21][22]24] if their synthesis can be easily performed and is not too expensive. The continuous feeding of the nanomaterial as required by a FIA instrument would rise the costs for continuous operation, otherwise.…”

Ultrasensitive electrospun fluorescent nanofibrous membrane for rapid visual colorimetric detection of H2O2

“…Thus, recent years have attracted attention regarding the measurement of H 2 O 2 for environmental protection and human health. Until the recent past, various analytical techniques have been devised for the analysis of H 2 O 2 , including chemiluminescence, spectrophotometry, fluorescence, and electrochemical methods [5][6][7][8]. Although these methods offer high sensitivity, rapidity, they also pose disadvantages like increased time consumption, increased operating procedures, expensive reagents, high cost, and the instability of substrates.…”