TALANTA
·
2020
·
IF 5.339
Xiaoya Bi,Lijun Luo,Libo Li,Xiaohong Liu,Bainian Chen,Tianyan You
A new fluorescence aptasensor for Ochratoxin A (OTA) analysis in corn and barley flour was developed owing to the favourable quenching function of cobalt oxyhydroxide (CoOOH) nanosheets . The first combination of graphitic carbon nitride quantum dots (g-CNQDs) and CoOOH nanosheets as efficient energy donor-acceptor pair was reported, and the quenching mechanism was proved by investigating the fluorescence lifetime of g-CNQDs. The aptamer-modified g-CNQDs (g-CNQDs-apt) were adsorbed onto CoOOH nanosheets surface by van der Waals force . Consequently, the Förster resonance energy transfer (FRET) from g-CNQDs-apt to CoOOH nanosheets was initiated, leading to quenched fluorescence. With the addition of OTA, the linear aptamer specifically bound with OTA to form G-quadruplex, which had relatively weak interaction with the CoOOH nanosheets and separated from the nanosheets surface. Thus, the FRET process between g-CNQDs-apt and CoOOH nanosheets was hindered, leading to the fluorescence of g-CNQDs-apt recovered clearly. The developed aptasensor exhibited acceptable detection limit with 0.5 nM and desirable linear relationship from 1 nM to 140 nM. Meanwhile, the aptasensor possessed multiple advantages, including easy operation, rapid detection and high selectivity . Moreover, the aptamer sensing platform was favorably applied for OTA determination in cereal (barley and corn flour), in which the recoveries varied from 94.5% to 101% with the relative standard deviation under 2.24%.
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ACS Sensors
·
2020
·
IF 7.333
Xiao-Bin Huang,Shao-Hua Wu,Hao-Cheng Hu,Jian-Jun Sun
The “turn-on” mode surface-enhanced Raman scattering (SERS) aptasensor for ultrasensitive ochratoxin A (OTA) detection was developed based on the SERS “hot spots” of AuNanostar@4-MBA@Au core–shell nanostructures (AuNS@4-MBA@Au) and exonuclease III (Exo III)-assisted target cycle amplification strategy. Compared with conventional gold nanoparticles, AuNS@4-MBA@Au provides a much higher SERS enhancement factor because AuNS exhibits a larger surface roughness and the lightning rod effect, as well as an excellent electromagnetic field between the AuNS core and the Au shell, which contribute to the superstrong SERS signal. Meanwhile, Exo III-assisted target cycle amplification can be used as an effective method for the further amplified detection of OTA. Additionally, the utilization of streptavidin magnesphere paramagnetic particles offers a green, economical, and facile technology for the accumulation and separation of the signal probe AuNS@4-MBA@Au from solution. All these factors lead to a significant enhancement of detectable signals and superhigh sensitivity. As a result, the limit of detection as low as 0.25 fg mL–1 could be achieved, which was lower than that in the other reported literatures on SERS methods for OTA detection as we know. The developed SERS aptasensor also provides a promising tool for foodstuff detection.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 5
·1-9
·
IF 5.705
Yu Xinhui,Lin Yaohui,Wang Xusheng,Xu Liangjun,Wang Zongwen,Fu FengFu
An exonuclease-assisted multicolor aptasensor was developed for the visual detection of ochratoxin A (OTA). It is based on the etching of gold nanorods (AuNRs) mediated by a G-quadruplex-hemin DNAzyme. A DNA sequence (AG4-OTA) was designed that comprises a hemin aptamer and an OTA aptamer. OTA binds to AG4-OTA to form an antiparallel G-quadruplex, which halts its digestion by exonuclease I (Exo I) from the 3′-end of AG4-OTA. Thus, the retained hemin aptamer can bind to hemin to form a G-quadruplex-hemin DNAzyme. This DNAzyme has peroxidase-like activity that catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 to produce its diimine derivative (TMB 2+ ) in acidic solution. TMB 2+ can etch the AuNRs by oxidizing Au(0) into Au(I). This results in the generation of rainbow-like colors and provides a multicolor platform for the visual detection of OTA. The assay is based on the use of a single isolated aptamer and possesses obvious advantages such as multi-color visual inspection, relatively high sensitivity and accuracy. It can be used to detect as little as 30 nM concentrations of OTA by visual observation and even 10 nM concentrations by spectrophotometry. The method was successfully applied to the determination of OTA in spiked beer where it gave recoveries of 101–108%, with a relative standard deviation (RSD, n = 5) of <5%.
Schematic of an exonuclease-assisted multicolor bioassay based on the G-quadruplex-hemin DNAzyme-mediated etching of gold nanorods (AuNRs). It enables visual detection of ochratoxin A (OTA) with a detection limit of 30 nM.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Jidong Tang,Ling Wang,Wenjin Ma,Ping Fu,Yanlin Zhang,Xiaoqiong Li,Xiaoqi Tao
The application of the fluorescence resonance energy transfer (FRET) strategy in the detection of ochratoxin A (OTA) is restricted by factors such as the photobleaching of fluorescent dyes, the autofluorescence of ochratoxin A (OTA), and the necessity for excitation by an external light source. The chemiluminescence resonance energy transfer (CRET) technique provides a more effective solution to this issue. In this paper, we developed a novel CRET aptasensor, based on gold nanoparticle (AuNP)-mediated CRET and Nb.BbvCI-powered DNA walker signal amplification. In the AuNPs/Capture-DNA/HRP probe, horseradish peroxidase (HRP) approached the AuNP surface, resulting in CRET. AuNPs quenched the chemiluminescence generated by HRP-catalyzed luminol. The presence of OTA induced the separation of the Walk-DNA from the aptamer and the formation of a double strand with Capture-DNA. This activated Nb.BbvCI to cleave Capture-DNA, releasing HRP and Walk-DNA. The Walk-DNA acted as a DNA walker, moving toward the adjacent Capture-DNA and initiating the next cleavage by Nb.BbvCI. Ultimately, a significant amount of HRP was released from the AuNP surface, weakening the CRET effect while generating a strong chemiluminescent signal. The CRET aptasensor had a detection limit of 2.75 nM with a linear range of 5–40 nM and was applied to detect OTA in glutinous rice.
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TALANTA
·
2024
·
IF 5.6
Ling Gao,Yue Zhang,Lu Chen,Qingtong Zhou,Nandi Zhou,Xiaole Xia
Target specificity, one of aptamer characteristics that determine recognition efficiency of biosensors, is generally considered to be an intrinsic property of aptamer. However, a high-affinity aptamer may have additional target binding specificity, little is known about the specificity of aptamer binding to multiple targets, which may result in false-positive results that hinder the accuracy of detection. Herein, an aptamer OBA3 with dual target ochratoxin A (OTA) and norfloxacin (NOR) was used as an example to explore the binding specificity mechanism and developed rapid fluorescent aptasensing methods. The nucleotide 15th T of aptamer OBA3 was demonstrated to be critical for specificity and affinity binding of target OTA via site-saturation mutagenesis. Substituting the 15th T base for C base could directly improve recognition specificity of aptamer for NOR and remove the binding affinity for OTA. The combination of π-π stacking interactions, salt bridges and hydrogen bonds between loop pocket of aptamer and quinolone skeleton, piperazinyl group may contributes to the fluoroquinolone antibiotics (NOR and difloxacin)-aptamer recognition interaction. Based on this understanding, a dual-aptamer fluorescent biosensor was fabricated for simultaneous detection of OTA and NOR, which has a linear detection range of 50–6000 nM with a detection limit of 31 nM for OTA and NOR. Combined with T15C biosensor for eliminating interference of OTA, the assay was applied to milk samples with satisfactory recovery (94.06–100.93%), which can achieve detection of OTA and NOR individually within 40 min.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Chen Hu,Chao Yang,Bo Li,Bangzhu Peng
Consumption of contaminated wines is a significant source of ochratoxin A (OTA) intake in humans, yet existing techniques for OTA removal are inadequate. This study constructs a TiO 2 /SiO 2 /g-C 3 N 4 catalyst (TiSiMs-TCN) with a tubular structure, capable of efficiently removing OTA from both simulated and real wines under visible light irradiation. The results of experiments, characterizations, and theoretical calculations demonstrate that the incorporation of silica enhances the adsorption capacity for OTA, and the tubular structure improves the catalyst's photoelectric properties. The internal electric field between TiSiMs and TCN facilitates electron transfer and the generation of active species, rapidly degrading the adsorbed OTA and promoting the regeneration of active sites, thus maintaining continuous adsorption-photocatalysis synergy. The OTA degradation pathway was analyzed using the Fukui index, electrostatic potential distribution, and intermediate product identification. Toxicological experiments confirm that TiSiMs-TCN is a safe and stable material capable of effectively detoxifying OTA contamination.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Xiaoying Wang,Yanqun Shan,Miao Gong,Xin Jin,liangrui Lv,Meng Jiang,Jun Xu
A novel electrochemical sensor for ochratoxin A (OTA) based on the hairpin aptamer (HA) and double report DNA was constructed successfully. In the work, HA was chosen as the OTA recognition element and immobilized on the gold electrode (GE) via Au-S. Au nanoparticles (AuNPs) labeled double report DNA (rDNA1 and rDNA2) were symmetrically hybridized with HA simultaneously. Compared to the single report DNA, the strategy can dramatically increase the amount of AuNPs on the electrode surface and the stability of the HA to prevent lodging. The signal amplification was further implemented by using trithiocyanuric acid (TCA) to aggregate the AuNPs. Thus, it was observed that the differential pulse voltammetry (DPV) response of AuNPs was significantly amplified via multiple signal amplification strategy. When OTA was present, the HA was specifically combined with OTA to form the OTA-HA complex, which caused double report DNA to detach from the electrode, resulting in the decrease of the DPV response. The proposed electrochemical aptasensor can sensitively detect low concentrations of OTA by monitoring the OTA-dependent DPV intensity change. Under the optimized conditions, it exhibited wide linear ranges from 1 pg mL −1 to 1 ng mL −1 with a low detection limit of 0.5 pg mL −1 . The work provides a new idea for the various mycotoxins and even other substances detection at trace level.
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Foods
·
2022
·Vol. 11
·期 3
·335
·
IF 5.561
Disha Lu,Xu Wang,Ruijue Su,Yongjian Cheng,Hong Wang,Lin Luo,Zhili Xiao
A novel and efficient immunoaffinity column (IAC) based on bispecific monoclonal antibody (BsMAb) recognizing aflatoxin B1(AFB1) and ochratoxin A (OTA) was prepared and applied in simultaneous extraction of AFB1and OTA from food samples and detection of AFB1/OTA combined with ic-ELISA (indirect competitive ELISA). Two deficient cell lines, hypoxanthine guanine phosphoribosyl-transferase (HGPRT) deficient anti-AFB1hybridoma cell line and thymidine kinase (TK) deficient anti-OTA hybridoma cell line, were fused to generate a hybrid-hybridoma producing BsMAb against AFB1and OTA. The subtype of the BsMAb was IgG1via mouse antibody isotyping kit test. The purity and molecular weight of BsMAb were confirmed by SDS-PAGE method. The cross-reaction rate with AFB2was 37%, with AFG115%, with AFM148%, with AFM210%, and with OTB 36%. Negligible cross-reaction was observed with other tested compounds. The affinity constant (Ka) was determined by ELISA. The Ka (AFB1) and Ka (OTA) was 2.43 × 108L/mol and 1.57 × 108L/mol, respectively. Then the anti-AFB1/OTA BsMAb was coupled with CNBr-Sepharose, and an AFB1/OTA IAC was prepared. The coupling time and elution conditions of IAC were optimized. The coupling time was 1 h with 90% coupling rate, the eluent was methanol–water (60:40,v:v, pH 2.3) containing 1 mol/L NaCl, and the eluent volume was 4 mL. The column capacities of AFB1and OTA were 165.0 ng and 171.3 ng, respectively. After seven times of repeated use, the preservation rates of column capacity for AFB1and OTA were 69.3% and 68.0%, respectively. The ic-ELISA for AFB1and OTA were applied combined with IAC. The IC50(50% inhibiting concentration) of AFB1was 0.027 ng/mL, the limit of detection (LOD) was 0.004 ng/mL (0.032 µg/kg), and the linear range was 0.006 ng/mL~0.119 ng/mL. The IC50of OTA was 0.878 ng/mL, the LOD was 0.126 ng/mL (1.008 µg/kg), and the linear range was 0.259 ng/mL~6.178 ng/mL. Under optimum conditions, corn and wheat samples were pretreated with AFB1-OTA IAC. The recovery rates of AFB1and OTA were 95.4%~105.0% with ic-ELISA, and the correlations between the detection results and LC-MS were above 0.9. The developed IAC combined with ic-ELISA is reliable and could be applied to the detection of AFB1and OTA in grains.Keywords:aflatoxin B1;ochratoxin A;bispecific monoclonal antibody;immunoaffinity column;ic-ELISA
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Zhiwen Huang,María Luisa Cerón,Kehuai Feng,Dan Wang,María Belén Camarada,Xiaoning Liao
Exploration of an efficient ochratoxin A (OTA) screening technique is highly important because of its highly toxic effect on human health. Electrochemical sensor, characterized with high accuracy and precise, is an emerging detection technique for toxic agents in food samples. However, the inherent fouling effect and low electrochemical activity from OTA molecular hinder its practical application in OTA detection. Herein, we prepared a novel 0D/1D nanohybrid by anchoring black phosphorus quantum dots (BPQDs) over carboxylated multiwalled carbon nanotubes (CNTs-COOH) via a facile sonication assisted assembly approach. Characterization techniques together with theoretical approximations reveal that BPQDs can anchor onto the CNTs-COOH via strong covalent reaction, endowing the nanohybrid with high conductivity, high stability and high anti-fouling property. The electrochemical sensor constructed with the 0D/1D nanohybrid shows high electrochemical activity and a good antifouling effect in OTA detection. In optimized conditions, the sensor provide a quantitative determination of OTA in a wide concentration range from 0.4 to 10 μM with a detection limit of 0.03 μM. Moreover, the sensor shows high reproductivity and satisfactory anti-interference ability. Satisfactory recoveries that can comparable to those of high-performance liquid chromatography indicate that the sensor is promising for the trace-level analysis of OTA in agricultural crops.
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 8
·1-9
·
IF 5.833
Chen Ruipeng,Li Shuang,Sun Yunfeng,Huo Bingyang,Xia Yating,Qin Yingkai,Li Shuning,Shi Baodi,He Defu,Liang Jun,Gao Zhixian
The design and fabrication of a surface-enhanced Raman scattering (SERS) aptasensor for simultaneous detection of zearalenone (ZEN) and ochratoxin A (OTA) in wheat and corn samples is described. The capture and reporter probes were SH-cDNA-modified gold nanorods and SH-Apt-modified Au@Ag core-shell nanoparticles, respectively. After recognizing OTA and ZEN aptamers and complementary strands (SH-cDNA), the reporter probe generated a strong SERS signal. The preferred binding of OTA and ZEN aptamers to OTA and ZEN, respectively, caused reporter probes to release the capture probes, resulting in a linear decrease in SERS intensity. The detection of OTA showed good linearity with an R 2 value of 0.986, which could be maintained across a wide concentration range (0.01 to 100 ng/mL), with the limit of detection of 0.018 ng/mL. For detection of ZEN, good linearity with an R 2 value of 0.987 could be maintained across a wide concentration range (0.05 to 500 ng/mL), with 0.054 ng/mL as the limit of detection. Good accuracy (relative standard deviation < 4.2%) during mycotoxin determination as well as excellent quantitative recoveries (96.0–110.7%) during the analysis of spiked real samples was achieved. The proposed SERS aptasensor exhibited excellent performance in the detection of OTA and ZEN in real food samples. Hence, by simply changing the aptamer, this new model can be applied to the detection of multiple mycotoxins in the food industry. Graphical abstract
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RSC Advances
·
2021
·Vol. 11
·期 35
·21760-21766
·
IF 3.361
Zeling Zhang,Benchao Su,Huan Xu,Zhenyun He,Yuling Zhou,Qi Chen,Zhichang Sun,Hongmei Cao,Xing Liu
Ochratoxin A (OTA) is a common food contaminant with multiple toxicities and thus rapid and accurate detection of OTA is indispensable to minimize the threat of OTA to public health. Herein a novel enzyme cascade-amplified immunoassay (ECAIA) based on the mutated nanobody–alkaline phosphatase fusion (mNb–AP) and MnO2 nanosheets was established for detecting OTA in coffee. The detection principle is that the dual functional mNb–AP could specifically recognize OTA and dephosphorylate the ascorbic acid-2-phosphate (AAP) into ascorbic acid (AA), and the MnO2 nanosheets mimicking the oxidase could be reduced by AA into Mn2+ and catalyze the 3,3′,5,5′-tetramethyl benzidine into blue oxidized product for quantification. Using the optimal conditions, the ECAIA could be finished within 132.5 min and shows a limit of detection of 3.38 ng mL−1 (IC10) with an IC50 of 7.65 ng mL−1 and a linear range (IC20–IC80) of 4.55–12.85 ng mL−1. The ECAIA is highly selective for OTA. Good recovery rates (84.3–113%) with a relative standard deviation of 1.3–3% were obtained and confirmed by high performance liquid chromatography with a fluorescence detector. The developed ECAIA was demonstrated to be a useful tool for the detection of OTA in coffee which provides a reference for the analysis of other toxic small molecules.
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FOOD CHEMISTRY
·
2021
·
IF 7.514
Yingpan Song,Lina He,Shuai Zhang,Xiao Liu,Kun Chen,Qiaojuan Jia,Zhihong Zhang,Miao Du
Iron-based metal-organic framework, NH 2 -MIL-101(Fe), was doped with different dosages of cobalt phthalocyanine nanoparticles (CoPc) to synthesize a series of NH 2 -MIL-101(Fe)@CoPc nanocomposites. The NH 2 -MIL-101(Fe)@CoPc nanocomposites were then employed to construct novel impedimetric aptasensors for the detection of ochratoxin A (OTA). Combining the intrinsic advantages of NH 2 -MIL-101(Fe) (highly porous structure and excellently electrochemical activity) and CoPc (good physiochemical stability and strong bioaffinity), the NH 2 -MIL-101(Fe)@CoPc nanocomposites show promising properties, which are beneficial for immobilizing OTA-targeted aptamer strands. Amongst, the developed impedimetric aptasensor based on NH 2 -MIL-101(Fe)@CoPc 6:1 , prepared using the mass ratio of NH 2 -MIL-101(Fe):CoPc of 6:1, exhibits the best amplified electrochemical signal and highest sensitivity for detecting OTA. The detection limitation is 0.063 fg·mL −1 within the OTA concentration of 0.0001–100 pg·mL −1 , accompanying with high selectivity, good reproducibility and stability, acceptable regenerability, and wide applicability in diverse real samples. Consequently, the proposed sensing strategy can be applied for detecting OTA to cope with food safety.
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