ANALYTICAL CHEMISTRY
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2020
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IF 6.785
Xiao Zhang,Qin Yang,Yunhe Lang,Xia Jiang,Peng Wu
Horseradish peroxidase (HRP)-based assays feature particular interests because of the simple colorimetric readout. In these assays, 3,3′,5,5′-tetramethylbenzidine (TMB) is the most widely used chromogenic substrates for HRP. The later research in nanozyme and DNAzyme also used TMB (the chosen substrate) because they are both HRP-mimics. It should be noted that the substrate of HRP is not just limited to TMB but, in fact, a broad range of benzidine derivatives. However, except decreased carcinogenicity due to tetrasubstitution of benzidine, the rationale for the chosen substrate TMB is not clear yet. Here, we addressed such a fundamental issue from the chemistry point of view. Nine benzidine derivatives featuring varied properties (different substitution groups and varied number of substitutions) were selected and investigated with four typical TMB-involved chromogenic systems. Among the existing benzidine substrates that are used for peroxidase-based assays, TMB exhibited the highest sensitivity, better color purity of colored products, and reasonable stability of oxidation products. Moreover, two tetrasubstituted benzidine derivatives other than TMB (4OCH3 and 2OCH32CH3) were synthesized for comparison. It turned out that the performances (sensitivity, color purity, and stability of the colored products) of TMB are still superior, thus chemically confirming its status of “the chosen substrate” in colorimetric assays.
研究领域:
分析化学
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生物化学
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PubMed
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SENSORS AND ACTUATORS B-CHEMICAL
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2023
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IF 8.4
Minxin Mao,Fengxia Sun,Jun Wang,Xiuping Li,Qiuli Pan,Chifang Peng,Zhouping Wang
Nanozyme amplified lateral flow assay (LFA) demonstrated many attractive performances than the traditional gold nanoparticles (AuNPs) based LFA, however, they required several additional operations to implement the catalytic reaction of substrate. In this work, a chromogenic substrate integrated and nanozyme amplified aptamer lateral flow assay (CSNLFA) was constructed through automatic delivery of chromogenic substrate on strip. By introducing a sucrose-fixed chromogenic substrate loaded fiber (SCF) onto the sample pad of LFA strip, the CSNLFA platform achieved automated sequential catalytic reaction of substrate oxidation deposition after [email protected] nanozyme was fully captured at T line of strip. This design was applied in an acetamiprid aptamer LFA and the developed aptamer CSNLFA (Apt-CSNLFA) achieved a linear range of 1–150 ng/mL for acetamiprid with the limit of detection (LOD) of 0.17 ng/mL. The Apt-CSNLFA demonstrated similar analytical performance to the conventional aptamer NLFAs but eliminated the additional operations for catalytic signal amplification . In addition, the new method was applied to the detection of tomato samples spiked with acetamiprid. The recovery ranged from 95% to 106.4% was obtained, which demonstrated the high application potential in rapid detection of acetamiprid.
研究领域:
分析化学
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环境科学
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农业化学
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JOURNAL OF SEPARATION SCIENCE
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2020
·Vol. 43
·期 15
·3136-3145
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IF 2.878
Hao Zhang,Min Lu,Hui Jiang,Xu Wang,Feng-Qing Yang
In this study, a capillary electrophoresis-based online immobilized enzyme microreactor was developed for evaluating the inhibitory activity of green tea catechins and tea polyphenol extracts on trypsin. The immobilized trypsin activity and other kinetic parameters were evaluated by measuring the peak area of the hydrolyzate of chromogenic substrate S-2765. The results indicated that the activity of the immobilized trypsin remained approximately 90.0% of the initial immobilized enzyme activity after 30 runs. The value of Michaelis–Menten constant ( K m ) was (0.47 ± 0.08) mM, and the half-maximal inhibitory concentration (IC 50 ) and inhibition constant ( K i ) of benzamidine were measured as 3.34 and 3.00 mM, respectively. Then, the inhibitory activity of four main catechins (epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate) and three tea polyphenol extracts (green tea, white tea, and black tea) on trypsin were investigated. The results showed that four catechins and three tea polyphenol extracts had potential trypsin inhibitory activity. In addition, molecular docking results illustrated that epigallocatechin gallate, epicatechin gallate, epicatechin, and epigallocatechin were all located not only in the catalytic cavity, but also in the substrate-binding pocket of trypsin. These results indicated that the developed method is an effective tool for evaluating inhibitory activity of catechins on trypsin.
研究领域:
分析化学
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生物化学
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药理学
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食品科学
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BIOSENSORS & BIOELECTRONICS
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2023
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IF 12.6
Caixia Sun,Xue Zhang,Hao Huang,Ya Liu,Xianwei Mo,Yufei Feng,Jiahong Wang,Wenhua Zhou,Paul K. Chu,Xue-Feng Yu,Wenxin Liu
Nanozymes with enzyme-like characteristics have drawn wide interest but the catalytic activity and substrate selectivity of nanozymes still need improvement. Herein, Se-vacancy-rich TiSe 2-x @Au nanocomposites are designed and demonstrated as nanozymes. The TiSe 2-x @Au nanocomposites show excellent peroxidase-like activity and the chromogenic substrate p-phenylenediamine (PPD) can be selectively oxidized to compounds that exhibit an absorption peak at 413 nm that differs from that of self-oxidation or generally oxidized species, suggesting high catalytic activity and strong substrate selectivity. Theoretical calculations reveal that the PPD adsorption geometry at Se vacancies with an adsorption energy of −3.00 eV shows a unique spatial configuration and charge distribution , thereby inhibiting the free reaction and promoting both the activity and selectivity in PPD oxidation . The TiSe 2-x @Au colorimetric system exhibits a wide linear range of 0.015 mM–0.6 mM and a low detection limit of 0.0037 mM in the detection of glucose. The blood glucose detection performance for human serum samples is comparable to that of a commercial glucose meter in the hospital (relative standard deviation < 6%). Our findings demonstrate a new strategy for rapid and accurate detection of blood glucose and our results provide insights into the future design of nanozymes.
研究领域:
纳米技术
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生物催化
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分析化学
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材料科学
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生物化学
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PubMed
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