Methods and Applications in Fluorescence
·
2019
·Vol. 8
·期 1
·015003
·
IF 2.94
Lei Lv,Chengbi Cui,Wancui Xie,Wenyi Sun,Shuang Ji,Jing Tian,Zhijun Guo
A novel label-free fluorescence aptasensor used for the detection of ochratoxin A (OTA) is presented in this study. When aggregated on the surface of DNA aptamer, aggregation-induced emission (AIE) fluorescence probe presents turn-on fluorescence property. The method proposed in this article was based on an AIE probe, 4, 4-(1E,1E)-2, 2-(anthracene-9, 10-diyl) bis (ethene-2, 1-diyl) bis (N, N, N-trimethylbenzenaminium iodide) (DSAI). With OTA present, the aptamer will combine with OTA and the conformation of the aptamer will switch to an antiparallel G-quadruplex from the initial random coil, which obstructs its digestion by Exo I. After the solution is added with DSAI, DSAI will aggregate on the surface of the aptamer/OTA complex and produces a strong emission. In the range of 5 to 500 ng · ml−1 OTA concentrations, the fluorescence increases with a linear logarithm relationship. The detection limit is 1.9 ng · ml−1. This method was used to detect OTA in spiked real samples, with recoveries and RSDs in the range of 92.2% to 106.3%, and 2.7% to 5.2%, respectively.
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TALANTA
·
2023
·
IF 6.1
Pengfei Ma,Hualin Guo,Ke Li,Yin Zhang,Huiqing Guo,Zhouping Wang
Patulin (PAT) and ochratoxin A (OTA) are the two main mycotoxins present in apples. Herein, a sensitive aptasensor for simultaneous detection of PAT and ochratoxin OTA was developed. Dual-color gold nanoclusters (AuNCs) with enhanced fluorescence properties were synthesized and employed as fluorescence amplifiers. Two separated fluorescence peaks at 650 nm and 530 nm were monitored simultaneously by employing single excitation (405 nm), corresponding to the aptamer probes of Cys@BSA-AuNCs-Apt PAT and Arg@ATT-AuNCs-Apt OTA , respectively. The fluorescent aptasensor demonstrated satisfying specificity, storage ability and accuracy. Under the optimal experimental conditions, the linear detection range for PAT and OTA was 0.10–50 ng/mL, with the limit of detection of 0.09 ng/mL and 0.06 ng/mL, respectively. Most importantly, practicability of the constructed aptasensor were confirmed by conducting the determination of PAT and OTA in apple juice sample, indicating the great potential of the aptasensor in practical detection applications.
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ANALYTICA CHIMICA ACTA
·
2018
·
IF 5.123
Baoyi Shao,Xiaoyuan Ma,Sen Zhao,Yan Lv,Xu Hun,Haitao Wang,Zhouping Wang
Contamination of mycotoxins has been a general problem of food safety and afflicts people all around the world. Ochratoxin A (OTA), an abundant and representative food-contaminating mycotoxin, has a detrimental effect on our health. Herein, an ultrasensitive surface-enhanced Raman scattering (SERS) aptasensor was fabricated for OTA detection. Au (core) @Au-Ag (shell) nanogapped nanostructures ( [email protected] NNSs) were coupled with Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs) by OTA aptamer and its complementary DNA sequence . The distance between two nanoparticles become far away in presence of the OTA due to the affinity of aptamer. This effect can obviously bring about the change of Raman intensity which can be used for the detection of OTA. Compared with pure metal nanoparticles, [email protected] NNSs can effectively enhance the Raman intensity of Raman signal molecule (4-MBA) via the ultrasmall nanogap, which contribute to the sensitivity of the sensor system. Additionally, the utilization of Fe 3 O 4 MNPs offers a green, economical and facile technology to capture targets from solution. The specially modified aptamer and its complementary strand establish a bridge connecting between [email protected] NNSs and Fe 3 O 4 MNPs. In this study, OTA concentration with a linear range of 0.01–50 ng mL −1 and the limit of detection (LOD) was as low as 0.004 ng mL −1 . The proposed SERS aptasensor can combine both of these above type of materials and provide a rapid, sensitive, and low-cost methodology for numerous future applications of point-of-care diagnostics.
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ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yuan Xiang,María Belén Camarada,Yangping Wen,Hao Wu,Jinyin Chen,Mingfang Li,Xiaoning Liao
There are few reports on the electrochemical detection of ochratoxin A (OTA) using chemically modified electrode owing to the OTA poor electrochemical activity and strong fouling effect towards electrode surface. In this study, a novel nanosensor based on two-dimensional (2D) layered black phosphorene (BP) was successfully developed for the simple voltammetric detection of OTA in grape juice and red wine samples. The BP modified nanosensor showed a good linear electrochemical response towards OTA in a concentration range of 0.3–10 μg/mL with a detection limit of 0.18 μg/mL (S/N = 3) under the optimal conditions. A mechanism for the electrocatalytic oxidation of OTA was proposed and verified by density functional theory calculations that the oxidation of OTA is an irreversible electrochemical response with an adsorption-controlled process, and the nitrogen atom of the amide is oxidized to N + O − with two protons and two electrons. The proposed electrochemical sensor demonstrated good electrochemical stability, superior anti-fouling property and excellent sensitivity towards OTA detection. A satisfactory practicability with recoveries between 98.8% and 103.3% was obtained in real samples determination. This work puts forward a new sensing platform based on the two-dimensional layered graphene-like nanosensor for the electrochemical determination of mycotoxins in edible agricultural food.
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FOOD CHEMISTRY
·
2019
·
IF 5.399
Tao Wei,Pingping Ren,Linli Huang,Zicheng Ouyang,Ziying Wang,Xiangfeng Kong,Tiejun Li,Yulong Yin,Yongning Wu,Qinghua He
Mycotoxins are toxic metabolites produced by fungi or molds, which may cause serious harm to human health through polluted cereal foods. In order to measure the typical mycotoxin contaminations in wheat and corn, a surface plasmon resonance (SPR) method was established using SPR sensor chip that was fabricated based on self-assembled monolayer. The minimum detection limit of aflatoxin B1, ochratoxin A, zearalenone and deoxynivalenol were identified as 0.59 ng/mL, 1.27 ng/mL, 7.07 ng/mL and 3.26 ng/mL, respectively. The cross-reactivity for all four mycotoxins were demonstrated to be low. Moreover, the test data were compared with HPLC-MS/MS confirmatory analysis results and good agreement was found between them. In conclusion, the SPR method for simultaneously detecting four mycotoxins has been developed with high sensitivity, good linearity and specificity, which can meet the detection requirements of cereal foods.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·1909-1916
·
IF 4.831
Dai Shaoliang,Wu Shijia,Duan Nuo,Wang Zhouping
The authors describe a turn-on luminescence resonance energy transfer (LRET) method for the detection of the mycotoxin Ochratoxin A (OTA). It utilizes upconversion nanoparticles (UCNPs) of the type NaYF 4 : Yb, Er as the energy donor and gold nanorods (Au NRs) as the acceptor. Biotin-labeled OTA aptamers were bound to the surface of the avidin-functionalized UCNPs. The AuNRs, in turn, were modified with thiolated OTA aptamer cDNA via thiol chemistry. The emission band of the UCNPs under 980-nm laser excitation has a maximum peaking at 657 nm and overlaps the absorption band of the AuNRs which peaks at 660 nm. Quenching of luminescence occurs because the hybridization actions shorten the distance between UCNPs and AuNRs. If, however, OTA is added, the two kinds of particles separate again because of the high affinity between OTA and the OTA aptamer. As a result, luminescence is recovered. The calibration plot is linear in the 0.05 to 100 ng mL −1 OTA concentration range, and the limit of detection is 27 pg mL −1 . The method was successfully applied to the determination of OTA in beer.
The luminescence of aptamer-modified upconversion nanoparticles (avidin-UCNPs) is quenched by cDNA-modified gold nanorods (AuNRs) due to hybridization. In the presence of Ochratoxin A (OTA), however, the luminescence of the UCNPs recovers due to competitive binding of aptamer to OTA.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2024
·
IF 6.2
Bu-Da Su,Xiao-Meng Li,Zhi-Wei Huang,Yue Wang,Jia Shao,Yan-Yan Xu,Le-Xin Shu,Yu-Bo Li
Ochratoxin A (OTA) is a common fungal toxin frequently detected in food and human plasma samples. Currently, the physiologically based toxicokinetic (PBTK) model plays an active role in dose translation and can improve and enhance the risk assessment of toxins. In this study, the PBTK model of OTA in rats and humans was established based on knowledge of OTA-specific absorption, distribution, metabolism, and excretion (ADME) in order to better explain the disposition of OTA in humans and the discrepancies with other species. The models were calibrated and optimized using the available kinetic and toxicokinetic (TK) data, and independent test datasets were used for model evaluation. Subsequently, sensitivity analyses and population simulations were performed to characterize the extent to which variations in physiological and specific chemical parameters affected the model output. Finally, the constructed models were used for dose extrapolation of OTA, including the rat-to-human dose adjustment factor (DAF) and the human exposure conversion factor (ECF). The results showed that the unbound fraction (F up ) of OTA in plasma of rat and human was 0.02–0.04% and 0.13–4.21%, respectively. In vitro experiments, the maximum enzyme velocity (V max ) and Michaelis–Menten constant (K m ) of OTA in rat and human liver microsomes were 3.86 and 78.17 μg/g min −1 , 0.46 and 4.108 μg/mL, respectively. The predicted results of the model were in good agreement with the observed data, and the models in rats and humans were verified. The PBTK model derived a DAF of 0.1081 between rats and humans, whereas the ECF was 2.03. The established PBTK model can be used to estimate short- or long-term OTA exposure levels in rats and humans, with the capacity for dose translation of OTA to provide the underlying data for risk assessment of OTA.
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JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Yongli Zhang,Zhenyun He,Zhichang Sun,Sihang Zhang,Xing Liu
Ochratoxin A (OTA) poses significant risks to both environment and human health, necessitating the development of rapid and sensitive detection methods. Lateral flow immunosensors (LFIs) typically use monoclonal antibodies and artificial antigens for mycotoxin detection; however, the preparation of these components is time-intensive, laborious, costly, and environmentally harmful. Herein, we developed an innovative genetic engineering-powered colorimetric/fluorescent dual-mode LFI (CM/FL-dLFI) using nanobodies and the mimotope peptide (MP) of OTA. Initially, a heptameric bifunctional fusion (sfGFP-C4bpα-Y4) containing the superfolder green fluorescent protein, the C4-binding protein α-chain, and the MP Y4 was constructed. The fusion was subsequently labeled on gold nanoflowers (AuNFs) to create the AuNFs@sfGFP-C4bpα-Y4 probe, which can be captured by the nanobody heptamer (Nb-C4bpα) and provides colorimetric/fluorescent signals. The optimized CM/FL-dLFI achieved a colorimetric limit of detection (LOD) of 0.01 ng/mL and a fluorescent LOD of 0.05 ng/mL. It exhibited high selectivity for OTA, good recovery rates of 82.85–102.81 % with relative standard deviations not exceeding 14 %, and excellent long-term stability. Moreover, it showed strong correlation with high-performance liquid chromatography in the analysis of 11 real pepper samples. Therefore, this study highlights the promising application potential of nanobodies and MPs in developing an economical and eco-friendly LFI for OTA detection in pepper.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Fujing Mao,Zhenyun He,Zhichang Sun,Sihang Zhang,Hongmei Cao,Xing Liu
Ochratoxin A (OTA) in food poses a serious challenge to public health. Herein, using the nanobody-driven controllable aggregation of gold nanoparticles (AuNPs) in a glucose oxidase-tyramine-horseradish peroxidase (GOx-TYR-HRP) system, we propose a direct competitive plasmonic enzyme immunoassay (dc-PEIA) for OTA detection. The OTA-GOx conjugate catalyzes glucose to produce hydrogen peroxide (H 2 O 2 ), and then HRP catalyzes H 2 O 2 to generate hydroxyl radical which induces the crosslink of TYR. Crosslinked TYR leads to aggregation of AuNPs through strong electrostatic interactions, which is tunable based on the competition of OTA-GOx and free OTA for binding the immobilized nanobody. The optimized dc-PEIA achieves an instrumental limit of detection (LOD) of 0.275 ng/mL and a visual LOD of 1.56 ng/mL. It exhibits good selectivity for OTA and accuracy in the analysis of pepper samples, with the confirmation of high-performance liquid chromatography. Overall, the dc-PEIA is demonstrated as a useful tool for detecting OTA in food.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Hao-Ze Li,Hai-Long Qian,Shu-Ting Xu,Cheng Yang,Xiu-Ping Yan
Here, we report a monomer planarity modulation strategy for room-temperature constructing molecularly imprinted-covalent organic frameworks (MI-COFs) for selective extraction of ochratoxin A (OTA). 2,4,6-triformylphloroglucinol (Tp) was used as basic building block, while three amino monomers with different planarity were employed as modulators to explore the effect of planarity on the selectivity of MI-COFs. The MI-TpTapa constructed from Tp and the lowest planarity of monomer Tapa gave the highest selectivity for OTA, and was further used as the adsorbent for dispersed-solid phase extraction (DSPE) of OTA in alcohol samples. Coupling MI-TpTapa based DSPE with high-performance liquid chromatography allowed the matrix-effect free determination of OTA in alcohol samples with the limit of detection of 0.023 μg kg −1 and the recoveries of 91.4–97.6%. The relative standard deviation (RSD, n = 6) of intra and inter day was <3.2%. This work provides a new way to construct MI-COFs for selective extraction of hazardous targets.
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Foods
·
2024
·Vol. 13
·期 4
·595
·
IF 4.7
Yanxuan Li,Furong Shao,Jin Wu,Mingzhu Liu,Gaofang Cao,Zunquan Zhao,Jialei Bai,Zhixian Gao
Ochratoxin A (OTA) is a mycotoxin widely found in foodstuffs such as cereal grains. It greatly threatens human health owing to its strong toxicity and high stability. Aptasensors have emerged as promising tools for the analysis of small molecule contaminants. Nucleic-acid-based signal amplification enables detectable signals to be obtained from aptasensors. However, this strategy often requires the use of complex primers or multiple enzymes, entailing problems such as complex system instability. Herein, we propose a fluorescent aptasensor for the ultrasensitive detection of OTA in cereal products, with signal amplification through RecJfexonuclease-assisted target recycling. The aptamer/fluorescein-labeled complementary DNA (cDNA-FAM) duplex was effectively used as the target-recognition unit as well as the potential substrate for RecJfexonuclease cleavage. When the target invaded the aptamer-cDNA-FAM duplex to release cDNA-FAM, RecJfexonuclease could cleave the aptamer bonded with the target and release the target. Thus, the target-triggered cleavage cycling would continuously generate cDNA-FAM as a signaling group, specifically amplifying the response signal. The proposed exonuclease-assisted fluorescent aptasensor exhibited a good linear relationship with OTA concentration in the range from 1 pg/mL to 10 ng/mL with an ultralow limit of detection (6.2 ng/kg of cereal). The analytical method showed that recoveries of the cereal samples ranged from 83.7 to 109.3% with a repeatability relative standard deviation below 8%. Importantly, the proposed strategy is expected to become a common detection model because it can be adapted for other targets by replacing the aptamer. Thus, this model can guide the development of facile approaches for point-of-care testing applications.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2025
·
IF 4.6
Zhixiong Zheng,Yingli Guo,Bingyu Fu,Shengxin Wen,Dongfang Ma,Zhengwu Fang,Xingping Zhang,Hualin Yang
Ochratoxin A (OTA) is a mycotoxin which can seriously affect people's health. Therefore, it is urgent to establish a convenient, rapid and efficient method for detecting OTA. In this paper, a lateral flow immunoassay strip based on polydopamine nanoparticles (PDANs) and gold nanocluster (AuNC) was developed for rapid detection of OTA with colorimetric and fluorescence dual mode. Without OTA, the monoclonal antibody (mAb)-PDANs was captured by OTA-BSA on the Test line (T-line), and a brown line can be observed by naked eyes. Meanwhile, the fluorescence of AuNC which was pre-coated on the T-line was quenched by the PDANs. With OTA, the mAb-PDANs combined with OTA, and mAb-PDANs cannot be captured on the T-line by OTA-BSA. As a result, the brown line disappeared, and the fluorescence of AuNC recovered. The linear ranges of colorimetric and fluorescence modes were 3.90–62.5 ng/mL and 0.98–15.63 ng/mL with the limits of detection (LOD) of 0.084 ng/mL and 0.032 ng/mL, respectively. And the visual limits of detection (VLOD) were 0.25 ng/mL and 0.49 ng/mL, respectively. This novel test strip was convenient in on-site instant detection with good selectivity and satisfactory recovery.
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危险品化学品经营许可证（带存储）