Au@Ag Heterogeneous Nanorods as Nanozyme Interfaces with Peroxidase-Like Activity and Their Application for One-Pot Analysis of Glucose at Nearly Neutral pH

Abstract

As substitutes for natural peroxidases, most nanomaterial-based enzyme mimetics (nanozymes) have unique properties such as high stability, low-cost, large surface area, and high catalytic activity. However, they usually work in acidic conditions and thus impede their real applications. In this work, by modulating the nanostructure, composition, and surface property of the bimetallic materials, the positively charged poly(diallyldimethylammonium)-stabilized Au@Ag heterogeneous nanorods (NRs) were developed as synergistic peroxidase-like interfaces, which exhibited high activity over a wide pH range (pH 4.0-6.5) using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) as the chromogenic substrate. At pH 6.5, the peroxidase-like activity for the Au@Ag heterogeneous NRs was stable and optimal within 20-40 °C. Moreover, the Au@Ag heterogeneous NRs showed excellent temperature stability and long-term storage stability. Given these characters, the detection of H2O2 at pH 6.5 was proposed on the basis of the Au@Ag heterogeneous NRs catalyzing the colorimetric reaction of H2O2 and ABTS, where the oxidized ABTS showed a typical absorption peak at 414 nm. The absorbance at 414 nm was linear with H2O2 concentration from 0.01 to 10 mM. Further, considering that Au@Ag heterogeneous NRs and glucose oxidase (GOx) have similar optimal pH for catalytic activities, a novel one-pot method for the detection of glucose was developed by the coupled catalytic reaction using GOx, Au@Ag heterogeneous NRs, and ABTS at nearly neutral pH (pH 6.5) and 37 °C. This proposed method had simple and rapid processes, wide linear range (0.05-20 mM), and reliability for the successful analysis of real samples. On the basis of these attractive and unique characteristics, Au@Ag heterogeneous NRs can become promising substitutes for peroxidase in analytical chemistry and environmental science.

Peroxidase‐Like Activity of Smart Nanomaterials and Their Advanced Application in Colorimetric Glucose Biosensors

“…Bimetallic nanomaterials consist of two metals and often display enhanced catalytic performance than their monometallic counterparts because of a synergistic effect. Therefore, the peroxidase‐like activity of bimetal nanomaterials such as Au@M (M = Ag, Pt, Bi, Cu), AgM (M = Au, Pd, Pt), and Fe–Co NPs are studied by some groups. The mechanism of peroxidase‐like activity of these metal nanomaterials is that metal nanomaterials can break up the OO bond of H 2 O 2 into two ·OH radical.…”

“…The application of bimetallic nanomaterials for fabricate colormetric glucose biosensor based on the peroxidase‐like activity were reported by many groups as well . For examples, Huang et al reported that Fe–Co bimetallic alloy nanoparticles (Fe–Co NPs) possessed highly peroxidase‐like activity and its application for glucose biosensor.…”

Prussian blue nanocubes peroxidase mimetic-based colorimetric assay for screening acetylcholinesterase activity and its inhibitor

“…Peroxidase mimetics have been intensively utilized in the colorimetric assays for various analysts due to their low cost and high stability [31,[38][39][40][41][42][43]. Prussian blue nanoparticles (PB NPs) have also been proven to exhibit intrinsic peroxidase-like activity and they have been successfully used for colorimetric sensing of H 2 O 2 and glucose [44].…”

“Non‐Naked” Gold with Glucose Oxidase‐Like Activity: A Nanozyme for Tandem Catalysis

“…The regression equation was y = 2.984 x + 0.073 ( R 2 = 0.998) with the linear range of 0.001–0.3 × 10 −3 m . The limit of detection was 0.6 µM (S/N = 3), which was lower than that of reported two‐step assay and one‐pot enzymatic assay . In addition, the response time (30 min) was shorter than that (more than 7 h) of the reported Au NPs‐based enzyme‐free assay method .…”