Enhancement of the Peroxidase-Like Activity of Iodine-Capped Gold Nanoparticles for the Colorimetric Detection of Biothiols

Chia Chen Chang*, Tsz Lian Hsu, Chie Pein Chen, Chen Yu Chen*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

13 Scopus citations

Abstract

A colorimetric assay was developed for the detection of biothiols, based on the peroxidase-like activity of iodine-capped gold nanoparticles (AuNPs). These AuNPs show a synergetic effect in the form of peroxidase-mimicking activity at the interface of AuNPs, while free AuNPs and iodine alone have weak catalytic properties. Thus, iodine-capped AuNPs possess good intrinsic enzymatic activity and trigger the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB), leading to a change in color from colorless to yellow. When added to solution, biothiols, such as cysteine, strongly bind to the interface of AuNPs via gold-thiol bonds, inhibiting the catalytic activity of AuNPs, resulting in a decrease in oxidized TMB. Using this strategy, cysteine could be linearly determined, at a wide range of concentrations (0.5 to 20 µM), with a detection limit of 0.5 µM using UV-Vis spectroscopy. This method was applied for the detection of cysteine in diluted human urine.

Original languageEnglish
Article number113
JournalBiosensors
Volume10
Issue number9
DOIs
StatePublished - 09 2020

Bibliographical note

Publisher Copyright:
© 2020 by the authors.

Keywords

  • Catalytic gold nanoparticle
  • Colorimetric assay
  • Iodine
  • Peroxidase-like activity

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