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Updated: Feb 14, 2026
Fabrication of Thin Film Silver/Silver Chloride Electrodes with Finely Controlled Single Layer Silver Chloride
Published on: July 1, 2020
Detection of urinary spermine by using silver-gold/silver chloride nanozymes
Po-Chih Kuo1, Chia-Wen Lien1, Ju-Yi Mao2
1Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
Abstract:
In this paper, we report a simple one-step synthesis method for silver-gold bimetallic nanoparticles deposition on silver chloride nanosheets to form Ag-Au/AgCl nanohybrid with oxidase-like and peroxidase-like catalytic activity. We used these nanohybrid in the detection of spermine. First, 13 nm-sized Au NPs were synthesized by citrate reduction of HAuCl4 solution, and then, Ag+ ions were added to the solution without any purification. The added Ag+ reacted with the Cl- ions in the dispersion, thus immediately forming AgCl nanosheets through a precipitation reaction, and the aurophilic interactions with the Au NPs resulted in the formation and in situ self-deposition of Ag-Au NPs on the AgCl nanosheets at room temperature. We investigated the enzyme-mimicking activity of the Ag-Au/AgCl nanohybrid in detail via the O2- or H2O2-Amplex Red (AR) redox system. The Ag-Au/AgCl nanohybrid exhibited at least 150-fold higher catalytic activity than that of Ag-Au NPs or AgCl nanosheets, due to synergistic effect. Spermine inhibited the enzyme-mimic activity of the Ag-Au/AgCl nanohybrid, thereby allowing for the construction of a probe for detecting nanomolar concentrations of spermine in urine samples. This cost-effective sensing system was used to easily and rapidly detect the concentrations of spermine in complex urine samples.
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