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Chromatographic Separation and Visual Detection on Wicking Microfluidics Devices
Published in Raju Khan, Chetna Dhand, S. K. Sanghi, Shabi Thankaraj Salammal, A. B. P. Mishra, Advanced Microfluidics-Based Point-of-Care Diagnostics, 2022
Keisham Radhapyari, Nirupama Guru Aribam, Suparna Datta, Snigdha Dutta, Rinkumoni Barman, Raju Khan
Kong et al. (2017) combined the adsorption capacity of molecularly imprinted polymer (MIP) membranes with ZnFe2O4 (Figure 14.5(I)) as peroxidase mimetics on one paper microzone through MIP membrane wrapping paper as well as its colorimetric potential to fabricate functional paper for the detection of bisphenol. The colorimetric sensor (Figure 14.5(II)) comprises two layers of patterned rectangular papers called an α-sheet comprising one working zone and a β-sheet with a circular contacting zone respectively from up to down. A wax screen-printed paper is oven treated at 130°C for 150 s so that the wax melts and penetrates the thickness of the paper creating hydrophobic barriers to form the microzone. The modification resulted in high performance and subsequent color development by H2O2 and 3,3',5,5' Tetramethylbenzidine (TMB), which can be observed with the naked eye and quantified by software. The colorimetric sensor for detecting Bisphenol A (BPA) at pH 4.0 HAc-NaAc buffer using ZnFe2O4 as a catalyst and H2O2 as an enzyme-substrate gave a correlation coefficient of 0.9945, with a LOD of 6.18 nM with high selectivity, sensitivity, and regeneration in a complicated matrix.
Nanomaterials-Based Biosensor Application in Environmental Protection
Published in Jayeeta Chattopadhyay, Nimmy Srivastava, Application of Nanomaterials in Chemical Sensors and Biosensors, 2021
Jayeeta Chattopadhyay, Nimmy Srivastava
(ii) Neonicotinoids—First introduced in 1980, neonicotinoids are the largest class of insecticides to be used for agricultural purposes (Jeschke et al. 2011) and are neuro-active. As reported by various researchers, they skeptically affect human health (Simon-Delso et al. 2015). Most of the sensors devised for the detection of neonicotinoids are focused on the detection of acetamiprid with aid of recognition element aptamer (Verdian 2018). It was in 2014 when Weerathunge et al. developed a sensor exploiting aptamer which is based on peroxidase-like activity of gold nanoparticles (Weerathunge et al. 2014). TMB (3,3,5,5-tetramethyl benzidine) was used as a reporter molecule that can change its color to purplish-blue on oxidation. When there is the presence of acetamiprid-specific aptamer, TMB oxidation is blocked as a result it remains colorless. The estimation limit obtained for this scheme was 0.1 ppm.
Nanozymes and Their Applications in Biomedicine
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Qian Liang, Ruofei Zhang, Xiyun Yan, Kelong Fan
Many antigens can be detected rapidly by using an immunological detection method employing nanozymes. In situ growth of porous platinum NPs on graphene oxide (Pt NPs/GO) can act as a colorimetric assay for the direct detection of cancer cells. Through antibody targeting, this system can specifically detect tumor cells expressing corresponding antigens. After specific binding with tumor cells, it can catalyze the substrate TMB to produce a color reaction, thus achieving the goal of cancer detection. Doping with Pt greatly improves the peroxidase-like activity of GO, which showed a higher affinity for TMB than HRP (Figure 15.12a) (Ling-Na Zhang 2014).
Heterogeneous catalytic activation of peroxymonosulfate by Ag@Cu2O composite for Au3+ detection
Published in Journal of Dispersion Science and Technology, 2023
Runmian Ming, Cailing Zhang, Liangbo Xie, Jing Chang, Yi Li
Chloroauric acid (HAuCl4, 23.5%–23.8%), nickel nitrate, sodium citrate and peroxymonosulfate (PMS, KHSO5·0.5KHSO4·0.5K2SO4) were obtained from Aladdin in China. 3,3′,5, 5′-tetramethylbenzidine (TMB, 99%) was purchased from Meryer Chemical Technology Co. Ltd. Polyvinylpyrrolidone (PVP) was received from Tianjin Jerzheng Chemical Trading Co. Ltd. Cupric nitrate (Cu(NO3)2, 99%) was obtained from RON Reagent. Methyl alcohol (MeOH), tertiary butanol (TBA), hydrazine hydrate (N2H4·H2O, 80%), silver nitrate (AgNO3, 99.8%) and interfering ions (SO42−, Na+, Cl−, Ca2+, NH4+, K+, Mg2+, CO32−, Co2+, Zn2+, and Ba2+) were received from Tianjin Jiangtian Chemical Industry Co. Ltd. Other interfering ions (Pb2+, Cr3+, Mn2+, Cd2+, Al3+, Fe2+, Fe3+, and F−) were purchased from Tianjin Yuanli Chemical Co. Ltd. All of the above reagents were analytical grade and have not undergone secondary treatment. All water used was triply-distilled (18 MΩ) in experiment.
Synthesis and peroxidase-like mimic study in H2O2 detection of a stable polyoxometalate-pillared coordination polymer
Published in Journal of Coordination Chemistry, 2018
Jianing Wang, Hairui Zhou, Maokui Ge, Yunliang Wang, Yiqiyuan Zhang, Hongjun Lu
Artificial enzyme mimics have attracted attention because they can overcome the disadvantages of natural enzymes including low operational stability as well as time waste, to some extent [1–5]. Since peroxidase enzymes could activate H2O2 to perform oxidations in nature, detecting and quantifying amounts of H2O2 has attracted attention because its production may affect human health [6–9]. This motivates us to develop an efficient specific system in biomimetic chemistry. Horseradish peroxidase (HRP), the effective catalytic agent used in optical H2O2 detection, can catalyze achromogenic 3,3′,5,5′-tetramethylbenzidine (TMB) forming a blue product. However, inherent drawbacks of this natural enzyme hinder its application in H2O2 detection [10,11]. As a consequence, considerable efforts have been dedicated to design compounds as artificial enzymes to replace the natural enzymes, such as Fe3O4 magnetic nanoparticles [12], many carbon-materials [13,14] and nanocomposites [15]. However, most reported artificial enzymes suffer from drawbacks, including difficulty in preparation and purification, low stability or relative sensitivity to environmental changes or poor peroxidase-like performance. Further developing superior enzyme mimics with higher sensitivity, reusability, and stability is required in the field of biomimetic chemistry.
Global mapping of research outputs on nanoparticles with peroxidase mimetic activity from 2010–2019
Published in Inorganic and Nano-Metal Chemistry, 2023
Raphael Idowu Adeoye, Kunle Okaiyeto, Oluwafemi Omoniyi Oguntibeju
For most peroxidases, the typical substrates are small aromatic molecules. Commonly used peroxidase chromogenic substrates include 2,2′-azino-bis-(3-ethylbenzothiozoline-6-sulfonic acid (ABTS), 3,3′,5,5′-tetramethylbenzidine (TMB), pyrrogallol, o-phenylenediamine (OPD), 4-aminoantypyrine. However, TMB is the most-studied chromogen for nanozymes with peroxidase mimic in an acidic medium due to its high absorption and stability of the reaction products. TMB can be oxidized to a blue intermediate product, TMB+·, this color change can be read at a wavelength of 370 or 650 nm.[4,21] The addition of sufficient acid oxidizes the blue product to a yellow diimine product that can be measured at 450 nm.[22] TMB is preferred as a reducing substrate in applications that require visual detection of target analytes.[10] ABTS is oxidized by peroxidase with the aid of H2O2 into green ABTS+·, which can be monitored at a wavelength of 414 − 420 nm.[5,23,24] 4-amino antipyrine is another chromogenic agent for peroxidase, it utilizes H2O2 to produce quinone imine dye which can be detected at a wavelength of 500 nm.[25] Pyrogallol is a colorless solution that turned yellow when oxidized by hydrogen peroxide due to the formation of purpurogallin, in which absorbance can be followed at 420 nm.[26] The oxidation product of o-phenylenediamine by peroxidase produces the orange-brown color of 2,3-diaminophenazine which can be read spectrophotometrically at 450 nm.[27]