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525 results on '"Xu, Zhen-Lin"'

109. Ratiometric Fluorescence Immunoassay Based on MnO2Nanoflakes for Sensitive and Accurate Detection of Tricaine

Author

Liang, Hong-Wei, Jia, Bao-Zhu, Zhang, Wen-Feng, Wang, Xing-Xing, Zhou, Kai, Lei, Hong-Tao, Xu, Zhen-Lin, and Luo, Lin

Abstract

Tricaine is a common anesthetic used in the long-distance transport of live fish. Recently, its negative impact on human health has aroused extensive concern. Thus, rapid and reliable techniques for tricaine residue analysis are essential to ensuring the quality of aquatic products. Herein, a specific anti-tricaine monoclonal antibody (Mab) was prepared. Then, a sensitive and robust ratiometric fluorescence ELISA (RF-ELISA) was constructed for detecting tricaine based on two MnO2nanoflake-mediated (MnO2NFs) fluorogenic reactions. In the RF-ELISA protocol, MnO2NFs with oxidase-like activity can trigger the formation of fluorescent 2,3-diaminophenazine (oxOPD) with an emissive peak at 570 nm from non-fluorescent o-phenylenediamine (OPD), while ascorbic acid (AA) can decompose MnO2NFs to lose their oxidase-mimicking activity, which is accompanied by the oxidation of AA into dehydroascorbic acid (DHAA). The subsequent reaction between the generated DHAA and OPD will result in the production of 3-(1,2-dihydroxy ethyl)furo[3,4-b]quinoxalin-1(3H)-on (DFQ), which has a potent emission peak at 445 nm. By virtue of the alkaline phosphatase (ALP) labeled on the antibody, which can catalyze the production of AA from ascorbic acid 2-phosphate (AAP), the concentration of tricaine can be linked to the variation of the RF signal (F445/F570) via a competitive immunoreaction. After optimization, RF-ELISA displayed a detection limit (LOD) of 0.28 ng/mL toward tricaine (in buffer solution), which was 376-fold lower than that of the traditional colorimetric ELISA. For practical application, the LODs of RF-ELISA for tricaine detection in shrimp and tilapia samples were determined to be 2.8 and 5.6 ng/g, respectively. Recoveries for spiked shrimp and tilapia samples, as well as the validation data from LC–MS/MS, showed that RF-ELISA exhibited good accuracy, precision, and reliability. This RF-ELISA protocol opened up new ways for tricaine and other-target analyses in food safety detection.

Published
2023
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122. Development of Cu-doped CeO2 nanospheres mimic nanozyme-based immunoassay for the specific screening of Bacillus cereus.

Author

Meng, Jingnan, Shen, Haoran, Chen, Jialin, Shen, Xing, Xu, Zeke, Wang, Juan, Liu, Yingju, and Xu, Zhen-Lin

Subjects
BACILLUS cereus, IMMUNOASSAY, FOOD poisoning, PSEUDOPOTENTIAL method, SYNTHETIC enzymes, CATALYTIC activity, PEROXIDASE, MONOCLONAL antibodies
Abstract

Due to the highly similar genetic background, it is difficult to distinguish Bacillus cereus (B. cereus) with other members of B. cereus group. Herein, an antibody-based colorimetric immunoassay using Cu-doped CeO2 nanospheres as peroxidase mimics was developed for the detection of B. cereus in food. First, monoclonal antibodies (mAbs) and polyclonal antibody (pAb) with good specificity to B. cereus were prepared and characterized. Second, the regular-shaped hollow Cu/CeO2 nanospheres with highly catalytic activity and biocompatibility were synthesized as mimic nanozymes to capture secondary antibody. Finally, a sandwich colorimetric immunoassay for the specific and sensitive detection of B. cereus was developed, showing linear detection range from 3.2 × 102 to 1 × 105 CFU/mL and a limit detection of 1.7 × 102 CFU/mL. The developed immunoassay holds great potential as an effective tool for detecting B. cereus in food poisoning. [ABSTRACT FROM AUTHOR]

Published
2022
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125. Broad-specificity immunoassay for O,O-diethyl organophosphorus pesticides: application of molecular modeling to improve assay sensitivity and study antibody recognition

Author

Xu, Zhen-Lin, Shen, Yu-Dong, Zheng, Wen-Xu, Beier, Ross C., Xie, Gui-Mian, Dong, Jie-Xian, Yang, Jin-Yi, Wang, Hong, Lei, Hong-Tao, She, Zhi-Gang, and Sun, Yuan-Ming

Subjects
Immunoassay -- Methods, Pesticides -- Chemical properties, Pesticides -- Composition, Monoclonal antibodies -- Chemical properties, Chemistry
Abstract

A monoclonal antibody (mAb) against 4-(diethoxyphosphorothioyloxy)benzoic acid (hapten 1) was raised and used to develop a broad-specificity competitive indirect enzyme-linked immunosorbent assay (ciELISA) for 14 O,O-dlethyl organophosphorus pesticides (OPs). Computer-assisted molecular modeling was used to model two-dimensional (2D) and three-dimensional (3D) quantitative structure--activity relationships (QSARs) to study antibody recognition. On the basis of insights obtained from the QSAR models, two heterolognus coating haptens, 4-(diethoxyphosphorothioylamino)butanoic acid (hapten 2) and 4-(diethoxyphosphorothioyloxy)-2-methylbenzoic acid (hapten 3) were designed, synthesized, and used to develop heterolognus ciELISAs with significantly improved sensitivity. The heterolognus ciELISA using hapten 2 as the coating hapten showed good sensitivity in a broad-specific manner for eight O,O-diethyl OPs and may be used as a screening method for the determination of these OPs. Our studies demonstrated that molecular modeling can provide insights into the spatial and electronic effects of molecular structures that are important for antibody activity, which can then be used to improve immunoassay sensitivity. 10.1021/ac1018414

Published
2010

126. Enhanced Non-Toxic Immunodetection of Alternaria Mycotoxin Tenuazonic Acid Based on Ferritin-Displayed Anti-Idiotypic Nanobody-Nanoluciferase Multimers

Author

Wang, Feng, primary, Li, Zhen-Feng, additional, Wan, De-Bin, additional, Vasylieva, Natalia, additional, Shen, Yu-Dong, additional, Xu, Zhen-Lin, additional, Yang, Jin-Yi, additional, Gettemans, Jan, additional, Wang, Hong, additional, Hammock, Bruce D., additional, and Sun, Yuan-Ming, additional

Published
2021
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138. Highly selective monoclonal antibody-based lateral flow immunoassay for visual and sensitive determination of conazole fungicides propiconazole in vegetables.

Author

Xu, Ze-Ke, Meng, Jing-Nan, Lei, Yi, Yang, Xing-Xing, Yan, Yi-Yong, Liu, Hai-Hong, Lei, Hong-Tao, Wang, Ting-Cai, Shen, Xing, and Xu, Zhen-Lin

Subjects
PROPICONAZOLE, IMMUNOASSAY, FUNGICIDES, LIQUID chromatography-mass spectrometry, MONOCLONAL antibodies, VEGETABLES, DETECTION limit
Abstract

The conazole fungicide propiconazole is frequently found in vegetables although usage is not allowed. To overcome the high-cost and time-consuming labour requirements of instrumental methods, we developed a simple and visual lateral flow immunoassay for the sensitive determination of propiconazole. A hapten was carefully designed to raise a monoclonal antibody against propiconazole. Bal b/c mice were immunised with the hapten-carrier protein conjugate and a specific monoclonal antibody (mAb) was produced. Based on this mAb, a sensitive immunochromatographic strip assay (ICA) was established for rapid screening of propiconazole in vegetable samples. After optimisation of analytical parameters, the ICA strip showed a detection limit of 0.13 ng g−1 and a linear range from 0.5 to 80 ng g−1 using a strip reader. The assay also can be read by the naked eye with a visual limit of detection of 80 ng g−1. The recoveries for spiked vegetable samples by ICA ranged from 85.2% to 114.9%, with a coefficient of variation less than 11.7%. The assay time is within 45 min for a single sample including the sample pre-treatment. For spiked and blind samples, the detection capability of ICA was equivalent to liquid chromatography-mass spectrometry. [ABSTRACT FROM AUTHOR]

Published
2022
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139. The Most Active Oxidase‐Mimicking Mn2O3 Nanozyme for Biosensor Signal Generation.

Author

Chen, Zi‐Jian, Huang, Zhicheng, Sun, Yuan‐Ming, Xu, Zhen‐Lin, and Liu, Juewen

Subjects
HORSERADISH peroxidase, BLOOD proteins, BIOSENSORS, SERUM albumin, IMMUNOGLOBULINS, GLUTARALDEHYDE
Abstract

Oxidase‐mimicking nanozymes are more desirable than peroxidase‐mimicking ones since H2O2 can be omitted. However, only a few nanomaterials are known for oxidase‐like activities. In this work, we compared the activity of Mn2O3, Mn3O4 and MnO2 and found that Mn2O3 had the highest oxidase activity. Interestingly, the activity of Mn2O3 was even inhibited by H2O2. The oxidase‐like activity of Mn2O3 was not much affected by the presence of proteins such as bovine serum albumin (BSA), but the physisorption of antibodies to Mn2O3 was not strong enough to withstand the displacement by BSA. We then treated Mn2O3 with 3‐aminopropyltriethoxysilane to graft an amine group, which was used to conjugate antibodies using glutaraldehyde as a crosslinker. A one‐step indirect competitive ELISA (icELISA) was developed for the detection of isocarbophos, and an IC50 of 261.7 ng/mL was obtained, comparable with the results of the standard two‐step assay using horseradish peroxidase (HRP)‐labeled antibodies. This assay has the advantage of significant timesaving for rapid detection of large amounts of samples. This work has discovered a highly efficient oxidase‐mimicking nanozyme useful for various nano‐ and analytical applications. [ABSTRACT FROM AUTHOR]

Published
2021
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144. Effect of proteins on the oxidase-like activity of CeO2 nanozymes for immunoassays.

Author

Chen, Zi-Jian, Huang, Zhicheng, Huang, Song, Zhao, Jin-Lin, Sun, Yuanming, Xu, Zhen-Lin, and Liu, Juewen

Subjects
IMMUNOASSAY, HORSERADISH peroxidase, METAL nanoparticles, PROTEINS, SERUM albumin
Abstract

Having the benefits of low cost, excellent stability and tolerance to extreme conditions, nanozymes are a potential alternative of horseradish peroxidase (HRP) or other enzymes for bioanalytical chemistry, especially immunoassays. CeO2 nanoparticles have oxidase-mimicking activity and can avoid the use of unstable H2O2. For robust assays, the effect of proteins on the activity of CeO2 needs to be carefully studied. Herein, we studied the adsorption and desorption of bovine serum albumin (BSA) from CeO2. The CeO2 nanoparticles exhibited a higher protein adsorption capacity compared to the other tested metal oxide nanoparticles. Although the oxidase-like activity of CeO2 was inhibited by BSA, low concentrations of phosphate and fluoride ions boosted the activity of protein-capped CeO2. CeO2 was still active under strong acidic conditions and at high temperature, while HRP lost its activity. For immunoassay development, we covered CeO2 with an amine-modified silane for covalent conjugation to antibodies. A one-step indirect competitive ELISA for fenitrothion was developed, and an IC50 value of 35.6 ng mL−1 and a limit of detection of 2.1 ng mL−1 were obtained. [ABSTRACT FROM AUTHOR]

Published
2021
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146. Isolation of Bactrian Camel Single Domain Antibody for Parathion and Development of One-Step dc-FEIA Method Using VHH-Alkaline Phosphatase Fusion Protein

Author

Zhang, Yu-Qi, primary, Xu, Zhen-Lin, additional, Wang, Feng, additional, Cai, Jun, additional, Dong, Jie-Xian, additional, Zhang, Jin-Ru, additional, Si, Rui, additional, Wang, Cheng-Long, additional, Wang, Yu, additional, Shen, Yu-Dong, additional, Sun, Yuanming, additional, and Wang, Hong, additional

Published
2018
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149. Enhanced Non-Toxic Immunodetection of AlternariaMycotoxin Tenuazonic Acid Based on Ferritin-Displayed Anti-Idiotypic Nanobody-Nanoluciferase Multimers

Author

Wang, Feng, Li, Zhen-Feng, Wan, De-Bin, Vasylieva, Natalia, Shen, Yu-Dong, Xu, Zhen-Lin, Yang, Jin-Yi, Gettemans, Jan, Wang, Hong, Hammock, Bruce D., and Sun, Yuan-Ming

Abstract

The non-toxic immunoassay for mycotoxins is being paid more attention due to its advantages of higher safety and cost savings by using anti-idiotype antibodies to substitute toxins. In this study, with tenuazonic acid (TeA), a kind of highly toxic Alternariamycotoxin as the target, an enhanced non-toxic immunoassay was developed based on the ferritin-displayed anti-idiotypic nanobody-nanoluciferase multimers. First, three specific β-type anti-idiotype nanobodies (AId-Nbs) bearing the internal image of TeA mycotoxin were selected from an immune phage display library. Then, the AId-Nb 2D with the best performance was exploited to generate a nanoluciferase (Nluc)-functionalized fusion monomer, by which a one-step non-toxic immunodetection format for TeA was established and proven to be effective. To further improve the affinity of the monomer, a ferritin display strategy was used to prepare 2D-Nluc fusion multimers. Finally, an enhanced bioluminescent enzyme immunoassay (BLEIA) was established in which the half maximal inhibitory concentration (IC50) for TeA was 6.5 ng/mL with a 10.5-fold improvement of the 2D-based enzyme-linked immunosorbent assay (ELISA). The proposed assay exhibited high selectivities and good recoveries of 80.0–95.2%. The generated AId-Nb and ferritin-displayed AId-Nb-Nluc multimers were successfully extended to the application of TeA in food samples. This study brings a new strategy for production of multivalent AId-Nbs and non-toxic immunoassays for trace toxic contaminants.

Published
2021
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