Detection of urinary spermine by using silver-gold/silver chloride nanozymes

作者：Kuo Po Chih; Lien Chia Wen; Mao Ju Yi; Unnikrishnan Binesh; Chang Huan Tsung; Lin Han Jia; Huang Chih Ching

来源：Analytica Chimica Acta, 2018, 1009: 89-97.

DOI：10.1016/j.aca.2018.01.018

• Silver chloride nanosheets
• Silver-gold nanoparticles
• Peroxidase
• Spermine
• Urine

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 O-2- 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.

• 出版日期2018-6-7