Unusual switchable peroxidase-mimicking nanozyme for the determination of proteolytic biomarker

作     者：Claire McVey Natasha Logan Nguyen T. K. Thanh Christopher Elliott Cuong Cao 

作者机构：Institute for Global Food Security School of Biological Sciences Queens University Belfast 18-30 Malone Road Belfast BT9 5BN UK Biophysics Group Department of Physics and Astronomy University College London London WC1E 6BT UK UCL Healthcare Biomagnetic and Nanomaterials Laboratories 21 Albemarle Street London W1S 4BS UK Material and Advanced Technologies for Healthcare Queens University Belfast 18-30 Malone Road Belfast BT9 5BN UK 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2019年第12卷第3期

页      面：509-516页

核心收录：

学科分类：0839[工学-网络空间安全] 08[工学] 081201[工学-计算机系统结构] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：Ireland Agency (Invest NI)  and the support from the Queen's University of Belfast AMR Network (QUBAN) sponsored by the UK's Engineering and Physical Sciences Research Council (EPSRC) 

主　　题：gold nano particles peroxidase-mimicking nanozyme enzyme detection biomarkers 

摘      要：Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use sensing approach based on the switchable peroxidase-mimicking activity of plasmonic gold nanoparticles (AuNPs) that can catalyse for the oxidation of 3,3’,5’5-tetramethylbenzidine (TMB) for the determination of protease enzyme. The AuNP surface is modified with casein, showing dual functionalities. The first function of the coating molecule is to suppress the intrinsic peroxidase-mimicking activity of AuNPs by up to 77.1%, due to surface shielding effects. Secondly, casein also functions as recognition sites for the enzyme biomarker. In the presence of protease, the enzyme binds to and catalyses the degradation of the coating layer on the AuNP surface, resulting in the recovery of peroxidase-mimicking activity. This is shown visually in the development of a blue colored product (oxidised TMB) or spectroscopically as an increase in absorbance at 370 and 650 nm. This mechanism allows for the detection of protease at 44 ng·mL^-1 in 90 min. The nanosensor circumvents issues associated with current methods of detection in terms of ease of use, compatibility with point-of-care testing, low-cost production and short analysis time. The sensing approach has also been applied for the detection of protease spiked in ultra-heat treated (UHT) milk and synthetic human urine samples at a limit of detection of 490 and 176 ng·mL^-1, respectively, showing great potential in clinical diagnostics, food safety and quality control.