Molecular Diagnostic of Ochratoxin A with Specific Aptamers in Corn and Groundnut via Fabrication of A Microfluidic Device

Abstract Ochratoxin A (OTA) is one of the predominant mycotoxins that contaminate a wide range of food commodities. In the present study, a 36-mer aptamer was used as a molecular recognition element coupled with gold nanoparticles (AuNPs) for colorimetric detection of OTA in a microfluidic paper-based analytical device (µPADs). The µPADs consisted of three zones: control, detection, and sample, interconnected by channels. The biophysical characterizations of aptamer conjugated AuNPs were done by UV-vis spectroscopy (UV-vis), dynamic Light Scattering (DLS), and transmission electron microscopy (TEM). The developed colorimetric assay for OTA showed a limit of detection of 242, 545, and 95.69 ng/mL in water, corn, and groundnut, respectively. The HPLC detection method achieved acceptable coefficient in standard curves (r2 = 0.9995), better detection range, and recovery rates in spiked corn and groundnut samples as 43.61 ± 2.18% to 87.10 ± 1.82% and 42.01 ± 1.31% to 86.03 ± 2.64% after multiple sample extractions and cleanup steps. However, the developed µPADs analytical device had the potent ability to rapidly detect OTA without any extraction pre-requirement, derivatization, and cleanup steps, thus illustrating its feasibility in the animal health sector, agricultural, and food industries.

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Enhancement of the Peroxidase-Like Activity of Iodine-Capped Gold Nanoparticles for the Colorimetric Detection of Biothiols

Biosensors ◽

10.3390/bios10090113 ◽

2020 ◽

Vol 10 (9) ◽

pp. 113 ◽

Cited By ~ 1

Author(s):

Chia-Chen Chang ◽

Tsz-Lian Hsu ◽

Chie-Pein Chen ◽

Chen-Yu Chen

Keyword(s):

Gold Nanoparticles ◽

Catalytic Activity ◽

Detection Limit ◽

Enzymatic Activity ◽

Catalytic Properties ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Synergetic Effect ◽

Vis Spectroscopy ◽

Wide Range

A colorimetric assay was developed for the detection of biothiols, based on the peroxidase-like activity of iodine-capped gold nanoparticles (AuNPs). These AuNPs show a synergetic effect in the form of peroxidase-mimicking activity at the interface of AuNPs, while free AuNPs and iodine alone have weak catalytic properties. Thus, iodine-capped AuNPs possess good intrinsic enzymatic activity and trigger the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB), leading to a change in color from colorless to yellow. When added to solution, biothiols, such as cysteine, strongly bind to the interface of AuNPs via gold-thiol bonds, inhibiting the catalytic activity of AuNPs, resulting in a decrease in oxidized TMB. Using this strategy, cysteine could be linearly determined, at a wide range of concentrations (0.5 to 20 μM), with a detection limit of 0.5 μM using UV-Vis spectroscopy. This method was applied for the detection of cysteine in diluted human urine.

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Colorimetric Detection of Hg2+ Based on the Promotion of Oxidase-Like Catalytic Activity of Ag Nanowires

International Journal of Nanoscience ◽

10.1142/s0219581x20500040 ◽

2020 ◽

Vol 19 (05) ◽

pp. 2050004

Author(s):

Leigang Cao ◽

Yumeng Fang ◽

Yue Zhang ◽

Jianzheng Yang ◽

Junhui He

Keyword(s):

Catalytic Activity ◽

Solvothermal Method ◽

Limit Of Detection ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Detection Range ◽

Optimum Parameters ◽

Ag Nanowires ◽

Colorimetric Reaction ◽

Excellent Selectivity

A portable Hg[Formula: see text]nanosensor was developed based on the colorimetric reaction by using the unmodified Ag nanowires (Ag NWs). Ag NWs were synthesized by a solvothermal method, with the length longer than 20[Formula: see text][Formula: see text]m and the diameter of [Formula: see text][Formula: see text]nm. The colorimetric assay can be affected by pH, temperature and the amount of Ag NWs, with the optimum parameters being 5, [Formula: see text]C and 100[Formula: see text][Formula: see text]L, respectively. The developed nanosensor presents excellent selectivity for Hg[Formula: see text]. The dynamic detection range is 25[Formula: see text]5000 ppb, and the limit of detection (LOD) for Hg[Formula: see text] is 19.9[Formula: see text]ppb. The developed Hg[Formula: see text] sensor shows great potentials in environmental monitoring and onsite analysis of Hg[Formula: see text].

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Microcantilever Resonators for Ochratoxin A Detection in Food and Drinks

10.20944/preprints201710.0083.v1 ◽

2017 ◽

Author(s):

Karin Santoro ◽

Ambra Prelle ◽

Davide Spadaro ◽

Maria Lodovica Gullino ◽

Carlo Ricciardi

Keyword(s):

Ochratoxin A ◽

Limit Of Detection ◽

Animal Health ◽

Food Contamination ◽

Grape Juice ◽

Calibration Plot ◽

Highly Sensitive ◽

Wide Range ◽

Time In Literature ◽

First Time

Mycotoxins food contamination represents a serious risk for consumers health. They are secondary metabolites of fungi that can be present in a wide range of foodstuffs. Ochratoxin A (OTA) is one of the most toxic compound and it is classified as a possible carcinogenic molecule. The harmful effects of OTA on human and animal health lead to a big boost to develop and optimize highly sensitive and accurate methods for OTA detection. An innovative and rapid detection method based on microcantilever resonators for ochratoxin A identification in food matrix has been developed. This work demonstrates the possibility to apply microcantilever technology in food safety field, showing for the first time in literature the successful detection of one of the most dangerous mycotoxin in different food matrixes both solids and liquids, such as green coffee, grape juice and wine. Sensing performances are discussed in terms of calibration plot and limit of detection.

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Colorimetric Detection of Trace Arsenic(III) in Aqueous Solution Using Arsenic Aptamer and Gold Nanoparticles

Australian Journal of Chemistry ◽

10.1071/ch13512 ◽

2014 ◽

Vol 67 (5) ◽

pp. 813 ◽

Cited By ~ 49

Author(s):

Minglei Yu

Keyword(s):

Aqueous Solution ◽

Gold Nanoparticles ◽

Detection Limit ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Colour Change ◽

Colorimetric Sensing ◽

Detection Range ◽

Colorimetric Indicator ◽

Blue Solution

In this study, trace arsenic(iii) (AsIII) in aqueous solution was detected by applying a classical aptamer-based gold nanoparticles colorimetric sensing strategy. An arsenic aptamer was used as a sensing probe and gold nanoparticles as a colorimetric indicator. In the absence of AsIII, the gold nanoparticles were stabilised by the arsenic aptamer and remained dispersed at high NaCl concentrations, displaying a red solution. Contrarily, in the presence of AsIII, the gold nanoparticles were prone to aggregation, owing to the formation of aptamer–AsIII complex between the arsenic aptamer and AsIII, and thus exhibited a blue solution. By monitoring the colour change, a simple and fast colorimetric assay for AsIII was established with a detection range of 1.26–200 ppb and a detection limit of 1.26 ppb. Because this colorimetric assay only involves common reagents and can be assessed visually, it holds great potential for arsenic(iii) monitoring in environment-related and other applications.

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In-Vitro Application of a Qatari Burkholderia cepacia strain (QBC03) in the Biocontrol of Mycotoxigenic Fungi and in the Reduction of Ochratoxin A biosynthesis by Aspergillus carbonarius

Toxins ◽

10.3390/toxins11120700 ◽

2019 ◽

Vol 11 (12) ◽

pp. 700 ◽

Cited By ~ 4

Author(s):

Randa Zeidan ◽

Zahoor Ul-Hassan ◽

Roda Al-Thani ◽

Quirico Migheli ◽

Samir Jaoua

Keyword(s):

Antifungal Activity ◽

Ochratoxin A ◽

Burkholderia Cepacia ◽

Culture Supernatant ◽

Animal Health ◽

Aspergillus Carbonarius ◽

Penicillium Verrucosum ◽

Wide Range ◽

Mycotoxigenic Fungi

Mycotoxins are secondary metabolites produced by certain filamentous fungi, causing human and animal health issues upon the ingestion of contaminated food and feed. Among the safest approaches to the control of mycotoxigenic fungi and mycotoxin detoxification is the application of microbial biocontrol agents. Burkholderia cepacia is known for producing metabolites active against a broad number of pathogenic fungi. In this study, the antifungal potential of a Qatari strain of Burkholderia cepacia (QBC03) was explored. QBC03 exhibited antifungal activity against a wide range of mycotoxigenic, as well as phytopathogenic, fungal genera and species. The QBC03 culture supernatant significantly inhibited the growth of Aspergillus carbonarius, Fusarium culmorum and Penicillium verrucosum in PDA medium, as well as A. carbonarius and P. verrucosum biomass in PDB medium. The QBC03 culture supernatant was found to dramatically reduce the synthesis of ochratoxin A (OTA) by A. carbonarius, in addition to inducing mycelia malformation. The antifungal activity of QBC03’s culture extract was retained following thermal treatment at 100 °C for 30 min. The findings of the present study advocate that QBC03 is a suitable biocontrol agent against toxigenic fungi, due to the inhibitory activity of its thermostable metabolites.

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A Colorimetric Aptamer Biosensor Based on Gold Nanoparticles for the Ultrasensitive and Specific Detection of Tetracycline in Milk

Australian Journal of Chemistry ◽

10.1071/ch12446 ◽

2013 ◽

Vol 66 (4) ◽

pp. 485 ◽

Cited By ~ 15

Author(s):

Lan He ◽

Yanfang Luo ◽

Wenting Zhi ◽

Yuangen Wu ◽

Pei Zhou

Keyword(s):

Gold Nanoparticles ◽

Detection Limit ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Colour Change ◽

Raw Milk ◽

Hexadecyltrimethylammonium Bromide ◽

Specific Detection ◽

Wide Range

This paper proposes a sensing strategy which employs an aptamer, unmodified gold nanoparticles (AuNP), and hexadecyltrimethylammonium bromide (CTAB) to detect tetracycline (TET) in raw milk. The method is based on the colorimetric assay of aggregating AuNP. In the absence of TET, the CTAB and aptamer form a complex which allows the aggregation of AuNP. In the presence of TET, the TET aptamer is exhausted first due to the formation of aptamer-TET complexes, which prevents assembly of the CTAB–aptamer supramolecule, causing a colour change and no aggregation of AuNP. This mechanism for the detection of TET proved to be sensitive and convenient. The colorimetric assay has a detection limit of 122 nM TET. This sensor has great potential for the sensitive, colorimetric detection of a wide range of molecular analytes.

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An Electrochemical Immunosensor Based on SPA and rGO-PEI-Ag-Nf for the Detection of Arsanilic Acid

Molecules ◽

10.3390/molecules27010172 ◽

2021 ◽

Vol 27 (1) ◽

pp. 172

Author(s):

Yanwei Wang ◽

Dongdong Ma ◽

Gaiping Zhang ◽

Xuannian Wang ◽

Jingming Zhou ◽

...

Keyword(s):

Electron Microscopy ◽

Limit Of Detection ◽

Electrochemical Immunosensor ◽

Detection Range ◽

Optimal Experiment ◽

Arsanilic Acid ◽

Transmission Electron ◽

Vis Spectroscopy ◽

Good Potential ◽

The Stability

A sensitive electrochemical immunosensor was prepared for rapid detection of ASA based on arsanilic acid (ASA) monoclonal antibody with high affinity. In the preparation of nanomaterials, polyethyleneimine (PEI) improved the stability of the solution and acted as a reducing agent to generate reduced graphene oxide (rGO) with relatively strong conductivity, thereby promoting the transfer of electrons. The dual conductivity of rGO and silver nanoparticles (AgNPs) improved the sensitivity of the sensor. The synthesis of nanomaterials were confirmed by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. In the optimal experiment conditions, the sensor could achieve the detection range of 0.50–500 ng mL−1 and the limit of detection (LOD) of 0.38 ng mL−1 (S/N = 3). Moreover, the sensor exhibited excellent specificity and acceptable stability, suggesting that the proposed sensor possessed a good potential in ASA detection. Thus, the as-prepared biosensor may be a potential way for detecting other antibiotics in meat and animal-derived foods.

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Label-Free Colorimetric Detection of Urine Glucose Based on Color Fading Using Smartphone Ambient-Light Sensor

Chemosensors ◽

10.3390/chemosensors8010010 ◽

2020 ◽

Vol 8 (1) ◽

pp. 10 ◽

Cited By ~ 1

Author(s):

Wang ◽

Guo ◽

Hu ◽

Liang ◽

Li ◽

...

Keyword(s):

Limit Of Detection ◽

Colorimetric Assay ◽

Point Of Care ◽

Colorimetric Detection ◽

Diabetic Patients ◽

Ambient Light ◽

Label Free ◽

Urine Glucose ◽

Light Sensor

In this work, a label-free colorimetric assay was developed for the determination of urine glucose using smartphone ambient-light sensor (ALS). Using horseradish peroxidase—hydrogen peroxide—3,3′,5,5′-tetramethylbenzidine (HRP-H2O2-TMB) colored system, quantitative H2O2 was added to samples to-be-determined for deepest color. The presence of glucose oxidase in urine led to the formation of H2O2 and the reduction of TMBred. As a result of this, the color of the urine faded and the solution changed from deep blue to light blue. We measured the illuminance of the transmitted light by a smartphone ambient light sensor, and thereby color changes were used to calculate the content of urine glucose. After method validation, this colorimetric assay was practically applied for the determination of urine samples from diabetic patients. Good linearity was obtained in the range of 0.039–10.000 mg/mL (R2 = 0.998), and a limit of detection was 0.005 mg/mL. Our method was had high accuracy, sensitivity, simplicity, rapidity, and visualization, providing a new sensor to be potentially applicable for point-of-care detection of urine glucose.

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Biogenic Silver Nanoparticles for Trace Colorimetric Sensing of Enzyme Disrupter Fungicide Vinclozolin

Nanomaterials ◽

10.3390/nano9111604 ◽

2019 ◽

Vol 9 (11) ◽

pp. 1604 ◽

Cited By ~ 2

Author(s):

Masood Hussain ◽

Ayman Nafady ◽

Sirajuddin ◽

Ahmet Avcı ◽

Erol Pehlivan ◽

...

Keyword(s):

Silver Nanoparticles ◽

Limit Of Detection ◽

Colorimetric Detection ◽

Localized Surface Plasmon ◽

Syzygium Aromaticum ◽

Colorimetric Sensing ◽

Green Protocol ◽

Vis Spectroscopy ◽

Clove Extract ◽

Average Size

We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2–20 nm (average size: 14.4 ± 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2–16 µM (R2 = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.

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Co-occurrence of Aflatoxins, Ochratoxin A, Fumonisins, and Zearalenone in Cereals and Feed, Determined by Competitive Direct Enzyme-Linked Immunosorbent Assay and Thin-Layer Chromatography

Archives of Industrial Hygiene and Toxicology ◽

10.2478/10004-1254-60-2009-1975 ◽

2009 ◽

Vol 60 (4) ◽

pp. 427-434 ◽

Cited By ~ 43

Author(s):

Maja Klarić ◽

Zdenka Cvetnić ◽

Stjepan Pepeljnjak ◽

Ivan Kosalec

Keyword(s):

Thin Layer ◽

Thin Layer Chromatography ◽

Ochratoxin A ◽

Immunosorbent Assay ◽

Limit Of Detection ◽

Permissible Limit ◽

Enzyme Linked Immunosorbent Assay ◽

Wide Range ◽

Food And Feed ◽

Layer Chromatography

Co-occurrence of Aflatoxins, Ochratoxin A, Fumonisins, and Zearalenone in Cereals and Feed, Determined by Competitive Direct Enzyme-Linked Immunosorbent Assay and Thin-Layer ChromatographyAspergillus, Penicillium, andFusariumspecies frequently contaminate crops. For this reason mycotoxins such as aflatoxins (AFs), ochratoxin A (OTA), fumonisins (FBs), and zearalenone (ZEA) are found in food and feed in a wide range of concentrations, depending on environmental and storage conditions. Consumption of mycotoxin-contaminated food and feed has been associated with acute and chronic poisoning and carcinoma. The aim of this study was to determine the incidence and co-occurrence of AFs (B1+B2+G1+G2), OTA, FBs (B1+B2+B3), and ZEA in 37 samples of cereals and feed randomly collected in 2007 from households of an endemic nephropathy (EN) area in Croatia. The mycotoxins were determined using the competitive direct ELISA test (CD-ELISA) in combination with thin-layer chromatography (TLC). The most frequent mycotoxin was ZEA (92%, mean 318.3 μg kg-1), followed by FBs (27%, 3690 μg kg-1), AFs (24.3%, 4.6 μg kg-1), and OTA (16.2%, 9.8 μg kg-1). Levels of AFs, ZEA, and FBs detected by CD-ELISA significantly correlated with the TLC results. However, only one OTA-positive sample was confirmed by TLC due to its high limit of detection. The levels of these mycotoxins were below the permissible limit for animal feed. Twenty-nine percent of cereals were contaminated with FBs, OTA, or ZEA in mass fractions above the permissible limit for humans. Co-occurrence of two toxins varied between 4.2% and 54% and of three between 4.2% and 7.6%. Prolonged co-exposure to AFs, OTA, FBs, and ZEA might increase the risk of various chronic diseases.

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