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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JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Yiqiong Chen,Maolin Chen,Jinxin Chi,Xia Yu,Yongxuan Chen,Xucong Lin,Zenghong Xie
A novel aptamer-based polyhedral oligomeric silsesquioxane (POSS)-containing hybrid affinity monolith has been prepared with a facile “one-pot” process simultaneously via “free radical polymerization” and “thiol-ene” click reaction, and used for on-line selective extraction and practical analysis to trace ochratoxin A (OTA). By using the ternary porogenic mixture composed of water/DMF/PEG, a homogeneous polymerization mixture with POSS chemicals, acrylate-based monomers and aptamer aqueous solution was obtained, and the copolymerization of POSS chemicals, polymer monomers and aptamer aqueous solution was systematically studied. Characterizations such as the morphology, FT-IR and fluorescence spectra, mechanical stability, dynamic binding capacity, cross-reactivity and selectivity of the resultant affinity monolith were also evaluated. Attributed to the porous monolithic structure and aptamer-based affinity interaction, acceptable selective recognition and recovery yields towards trace OTA were obtained. With a 5-fold volume enrichment, the limit of detection (LOD) and limit of quantitation (LOQ) of OTA in fortified beer samples were gained at 0.025 ng/mL (S/N = 3) and 0.045 ng/mL (S/N = 10), respectively. It could be competent for the sensitive measure of actual OTA residues in real beer samples. In comparison with the previously reported strategies containing common “sol-gel” chemistry, the proposed protocol to fabricating aptamer-modified POSS-containing hybrid affinity monolith showed a simpler preparation with acceptable selectivity and higher recovery to trace OTA.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Qingjie Yu,Chenxi Ke,Yu Wu,Zichen Song,Mengjiao Li,Hongda Zhu,Huiling Guo,Hongmei Sun,Mingxing Liu
Ochratoxin A (OTA) is a kind of mycotoxin , and developing a sensitive and simple method to detect OTA is of great significance for ensuring food safety and human health. In this study, a competitive fluorescent immunosensor based on fluorescence resonance energy transfer (FRET) was designed for the ultra-sensitive detection of OTA. Here, Ag@SiO 2 @N, S-GQDs nanocomposites were successfully designed, fabricated, and characterized by heteroatom co-doping and metal enhanced fluorescence (MEF) techniques, which can improve the fluorescence intensity and quantum yield . This study indicated that FRET between OTA antigen-modified Ag@SiO 2 @N, S-GQDs (Ag@SiO 2 @N, S-GQDs-OTA-Antigen) and OTA antibody-modified AuNPs can effectively quench the strong fluorescence of Ag@SiO 2 @N, S-GQDs-OTA-Antigen. The competitive fluorescent immunosensor based on FRET can detect OTA with a linear range of 0.5–1000 pg/mL and a limit of detection (LOD) of 0.094 pg/mL under optimal conditions. The recoveries ranged from 94% to 110% for the red wine sample, suggesting that the developed FRET-based competitive fluorescent immunosensor can be an effective tool for the ultra-sensitive detection of OTA, meanwhile, it might provide a better method for the detection of other toxic small molecules in food and the environment.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Li-Hong Yu,Yue-Hong Pang,Xiao-Fang Shen
Ochratoxin A (OTA) is a notable mycotoxin prevalent in grain products. In this paper, we computationally designed a high-affinity molecular recognition peptide (MRP, KQRLKCASLQKFGERAF) targeted at OTA according to structural analysis and molecular dynamics with a dissociation constant (K d ) of 12.18 ± 6.59 nM. A novel fluorescent probe, RhB-MRP (MRP-lysine-rhodamine B), was synthesized to convert the binding of MRP and OTA into optical signals. Based on RhB-MRP, we constructed a ratiometric fluorescence biosensor utilizing the classic blue fluorescent MOFs (NH 2 -MIL-88(Fe)). The fluorescence of NH 2 -MIL-88(Fe) was strongly quenched by RhB-MRP, which formed a ground state complex leading to static quenching. The developed biosensor exhibited exceptional sensitivity with detection limit of 0.32 pg mL −1 and rapid response time (11 min). A good recovery rate of 87.3–114.1 % was achieved in grain products. Although there are currently few MRPs that can specifically recognize small molecules, this highly sensitive and selective biosensor demonstrates the great potential of MRPs for detecting other molecules.
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ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Dehao Jia,Xiaoyue Zhang,Yue Jia,Xuejing Liu,Yu Du,Tingting Wu,Qin Wei,Bin Cai
Gold nanoclusters (AuNCs) exhibit unique optical properties and satisfactory biocompatibility, enabling them as highly promising electrochemiluminescence (ECL) emitters. However, the low ECL efficiency, resulting from the free movement of ligands, significantly hinders the development of AuNCs in the sensing field. In this work, polyelectrolytes were utilized to encapsulate AuNCs within the mesostructured silica xerogel, forming mesostructured silica xerogel-encapsulated gold nanoclusters (AuNCs@MSX). The space-confinement effect of the MSX and the uniform spatial distribution of encapsulated AuNCs reduced energy loss and the self-quenching effect. Compared with the aggregated AuNCs, the ECL efficiency of AuNCs@MSX increases by more than 2-fold. Meanwhile, the quantum yield can reach 16.98%. Furthermore, based on the ECL-resonance energy transfer (ECL-RET), an “on–off” ECL biosensor was designed. By the integration of a DNA walker cyclic amplification strategy, the exonuclease III (Exo III)-assisted biosensor enabled precise detection of ochratoxin A (OTA). As expected, the ECL biosensor exhibited an ideal linear ranging from 0.001 to 100 ng/mL, achieving a low detection limit of 0.31 pg/mL. The results confirm that encapsulating AuNCs in MSX to enhance ECL efficiency is a viable approach for preparing emitters in trace biomarker detection.
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Analytical Methods
·
2024
·Vol. 16
·期 18
·2897-2904
·
IF 2.7
Bingchen Wang,Yifan Wang,Xiuyuan Zhang,Kuo He
Ochratoxin A (OTA) is a mycotoxin that can contaminate a variety of agricultural commodities, including fruit juices and wines. The capability of a magnetic solid-phase extraction (MSPE) method with a magnetic metal–organic framework (MOF) material having a three-layer core–shell structure to improve the detection of OTA in food matrices using high performance liquid chromatography is described. Analysis of the material through X-ray diffraction (XRD) indicated the successful synthesis of the magnetic nanomaterial Fe3O4@SiO2@UiO66-NH2. Scanning electron microscopy (SEM) and Zetasizer lab indicated its nano-sized morphological features. The conditions affecting the magnetic solid-phase extraction procedure, such as material dosage, pH, composition and amount of eluent, desorption solution and desorption time were investigated to obtain the optimal extraction conditions. Under optimized conditions, the recoveries of spiked analytes at three different concentrations ranged from 95.83 to 101.5%, and the relative standard deviations were below 5%. Coupling with HPLC allowed the limit of detection to be 0.3 μg kg−1. This method is simple and specific, and can effectively avoid the influence of coexisting elements and improve the sensitivity of determination through fast MSPE of OTA. It has broad development prospects in OTA detection pre-treatment.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Xiao Liang,Qiu-Lan Li,Ji-Tao Li,Wen-Bo Zhao,De-Zhi Yang,Ya-Ling Yang,Zi-Tao Zhong
Ochratoxin A (OTA) is recognized as a Group 2B carcinogen and poses significant dangers to human, making it crucial to regulate OTA levels in food products. Herein, we developed a colorimetric approach to analyze OTA utilizing the intrinsic catalytic oxidized activity of Fe 3 O 4 magnetic nanoparticles (MNPs). Our findings reveal that OTA shows a significant impact on the absorbance signal of the catalytic system, notably reducing the absorbance at 532 nm with H 2 O 2 and 4-aminoantipyrene (4-AP). This sensor does not require elaborate aptamer or antibody, omitting the cumbersome reaction and the loss during synthesis, thus simply realizing OTA detection. The signal correlates linearly with the OTA concentrations and achieves satisfied sensitivity. The practical application has been verified utilizing beer and rice samples, resulting in recoveries ranging from 91.0 % to 106.2 %. This accuracy and reliability verified the method feasibility for monitoring OTA levels in food products.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Pengfei Yu,Yuyin Wu,Anqi Liu,Mati Ullah Khan,Jun Yang,Jiaqi Cui,Shun Wang,Jiawen Liu,Anqi Chu,Ling Kong,Zhiwei Chen
Ochratoxin A (OTA) is a kind of mycotoxin. It widely exists in all kinds of mammals and has teratogenicity and cytotoxicity. In this paper, a label-free photoelectrochemical (PEC) aptamer sensor based on bismuth oxyiodide/cadmium tungstate (BiOI/CdWO 4 ) was designed to detect OTA. The BiOI/CdWO 4 heterojunction is an excellent optoelectronic active material with remarkable chemical stability. AgNO 3 and Na 2 S were selected to grow in situ to form Ag 2 S quantum dots, which were sensitized to enhance the absorption of visible light and promote the generation of photocurrent. In this system, with the increasing of OTA concentration, the photoelectric signal intensity reduces as the specific binding with aptamer. When the concentration of OTA is between 0.01 ng/mL and 50.00 ng/mL, the linear equation is I (μA) = 48.95 – 10.276 lg c ( c OTA , ng/mL), R 2 = 99.281, and the detection limit is 0.823 pg/mL. The newly designed PEC aptamer sensor has exceptional stability, sensitivity, and reproducibility, making it capable of detecting OTA effectively and sensitively.
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MICROCHIMICA ACTA
·
2025
·Vol. 192
·期 8
·1-9
·
IF 5.3
Yang Yufan,Zhao Bo,Hu Xiaopeng,Gu Huiwen,Yan Xiu-Fang,Yin Xiaoli
A dual-mode fluorescent/colorimetric sensor is presented utilizing Au/ZIF-67 nanocomposites for an ultrasensitive ochratoxin A (OTA) detection. The system employs polydopamine-coated Fe 3 O 4 nanoparticles (Fe 3 O 4 @MIP) as magnetic recognition elements and aptamer/3,3′,5,5′-tetramethylbenzidine (TMB)-functionalized Au/ZIF-67 nanocomposites (Apt/TMB/Au/ZIF-67) as dual-signal probes for both fluorescence and colorimetric detection. Through molecular imprinting-aptamer synergistic recognition, OTA binding induces the formation of sandwich-structured particles (Fe 3 O 4 @MIP-OTA-Apt/TMB/Au/ZIF-67). Magnetic separation of these particles facilitates fluorescence measurements, while residual Apt/TMB/Au/ZIF-67 in solution permits simultaneous colorimetric detection. Crucially, fluorescence intensity increases while colorimetric absorption decreases proportionally with OTA concentration (0.5–25 ng mL⁻ 1 ), enabling self-validating dual-mode detection without requiring reagent replacement. The platform achieves detection limits of 0.15 ng mL⁻ 1 (fluorescence) and 0.13 ng mL⁻ 1 (colorimetry). The sensor was successfully validated for OTA quantification in real food samples, demonstrating significant potential for food safety applications. Graphical
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SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Xingliang Cheng,Ying Chen,Gongke Li,Yuling Hu
Nanozymes, as catalytic nanomaterials mimicking natural enzymes, have emerged as powerful tools for analytical sensing. However, conventional methods for nanozyme synthesis and immobilization often suffer from time-consuming processes and inefficient substrate integration. Herein, we develop an innovative electrochemical strategy that achieves simultaneous synthesis and immobilization of sponge-like two-dimensional tetrakis(4-carboxyphenyl)porphyrin-Fe (Cu-TCPP(Fe)) nanozymes (termed as STCTFzymes) on Cu foils within only 6 min. Kinetic analysis confirms that the electrochemical growth follows a diffusion-controlled instantaneous nucleation mechanism. The resulting STCTFzymes exhibit enhanced operational stability enabled by firm substrate anchoring and facile recyclability through physical retrieval of the copper support. Leaching tests and post-recycling structural analysis further validate the excellent structural integrity and anti-leaching capability of STCTFzymes. Given the excellent peroxidase-like (POD) activity of STCTFzymes, a surface-enhanced Raman scattering (SERS) method based on aptamer-specific recognition was developed using ochratoxin A (OTA) as a model analyte. The OTA aptamer was adsorbed on the surface of STCTFzymes to block the catalytic site and turn off the POD-like activity. Upon specific binding of OTA to the aptamer, the enzyme activity of STCTFzymes was reactivated, resulting in a favorable change in SERS signal. The established method showed a wide linear range (0.3–500 ng/mL) and low detection limit (0.091 ng/mL) for OTA, with superior selectivity, high sensitivity and satisfactory stability. This electrochemically-assisted self-assembly provides a new approach for developing robust nanozymes architectures on heterogeneous substrates. When synergistically integrated with aptamer-based recognition, the STCTFzymes presents a universal strategy for sensitive detection of biotoxins exhibiting inherently weak Raman response.
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Foods
·
2024
·Vol. 13
·期 14
·2177
·
IF 4.7
Yiwei Xu,Xupeng Jia,Sennan Yang,Mengrui Cao,Baoshan He,Wenjie Ren,Zhiguang Suo
A novel electrochemical aptasensor was prepared for the simultaneous determination of aflatoxin B1 (AFB1) and ochratoxin A (OTA). Composites of Au nanoparticles and polyethyleneimine-reduced graphene oxide (AuNPs/PEI-RGO) with good electrical conductivity and high specific surface area were employed as the supporting substrate, demonstrating the ability to provide more binding sites for aptamers and accelerate the electron transfer. Aptamers were immobilized on a AuNPs/PEI-RGO surface to specifically recognize AFB1 and OTA. A metal–organic framework of UiO-66-NH2served as the signal carrier to load metal ions of Cu2+and Pb2+, which facilitated the generation of independent current peaks and effectively improved the electrochemical signals. The prepared aptasensor exhibited sensitive current responses for AFB1 and OTA with a linear range of 0.01 to 1000 ng/mL, with detection limits of 6.2 ng/L for AFB1 and 3.7 ng/L for OTA, respectively. The aptasensor was applied to detect AFB1 and OTA in cereal samples, achieving results comparable with HPLC-MS, with recovery results from 92.5% to 104.1%. With these merits of high sensitivity and good selectivity and stability, the prepared aptasensor proved to be a powerful tool for evaluating contaminated cereals.
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TALANTA
·
2019
·
IF 4.916
Jingwen Gao,Ziyi Chen,Lebao Mao,Wei Zhang,Wei Wen,Xiuhua Zhang,Shengfu Wang
In this work, an innovative aptasensor based on electrochemiluminescence resonance energy transfer (ECL-RET) from CdTe quantum dots (QDs) to a cyanine dye (Cy5) fluorophore for the determination of Ochratoxin A (OTA) was fabricated. A strong cathodic ECL emission was obtained by the CdTe QDs modified glassy carbon electrode (GCE). After the immobilization with the capture DNA (cDNA) and the sequential hybridization with the probe DNA-modified Cy5 (pDNA, the aptamer of OTA), the ECL signal enhanced obviously through the ECL-RET. Meanwhile, the spectrum- and distance-related ECL enhancement effect was investigated. When the target OTA was in the presence, the pDNA-Cy5 molecules were released from the electrode surface owing to the specific interaction between OTA and aptamer, resulting in an evident decrease of ECL signal. Under optimal conditions, the developed aptasensor displayed the linear response toward OTA in the wide range of 0.0005–50 ng/mL with a low detection limit of 0.17 pg/mL. With the excellent selectivity , stability and repeatability, the strategy provided an efficient and universal method for the sensitive detection of target in practical application.
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