AsianScientist (Jul. 23, 2015) – In a study published in ACS Applied Materials & Interfaces, researchers describe an artificial peroxidase that is temperature stable and active at near neutral conditions.
Natural peroxidases, which catalyze the breakdown of hydrogen peroxide (H2O2) are of great practical significance in the fields of catalytic industry, pharmaceuticals, biosensor, food safety, environmental protection and genetic breeding. However, being proteins, natural peroxidases suffer some disadvantages such as complicated steps for isolation and purification, as well as denaturation in complex conditions.
As the efficient peroxidase alternatives, nanomaterial-based enzyme mimetics (nanozymes) have many unique properties including high stability, low cost, large surface-to-volume ratio and high catalytic activity. However, most of the peroxidase mimetics reported to date need to work in acidic conditions (pH<5.0) rather than nearly neutral conditions (pH 6.0-7.4), limiting their practical applications. Recently, Professor Liu Aihua and his team from the Biosensing Group, Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences, developed Au@Ag heterogeneous nanorods (Au@Ag NRs) synergistic peroxidase-like interfaces at nearly neutral pH. The researchers discovered that the catalytic activity of nanozyme can be regulated by modulating its nano-structure, composition, surface property of the bimetallic materials, substrates and pH value of the reaction solution. The positively charged Au@Ag NRs exhibit high activity to catalyze H2O2 over a wide pH range (pH 4.0-6.5) using 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) as the chromogenic substrate. In contrast, silver and gold nanoparticles on their own only show activity in acidic conditions (pH 3.5-4.5).
Moreover, the Au@Ag NRs show excellent temperature stability and long-term storage stability. Considering that the nanozyme and glucose oxidase (GOx) have similar optimal pH for catalytic activities, a novel one-pot method for the colorimetric detection of glucose was further developed by using GOx, Au@Ag NRs and ABTS at nearly neutral pH (pH 6.5).
This proposed method shows prominent advantages of low cost, wide linear range, high sensitivity and reliability for the successful analysis of glucose in real samples, which avoids the multi-step operation of conventional colorimetric methods.
The article can be found at: Han et al. (2015) Au@Ag Heterogeneous Nanorods as Nanozyme Interfaces with Peroxidase-Like Activity and Their Application for One-Pot Analysis of Glucose at Nearly Neutral pH.
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Source: Chinese Academy of Sciences.
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