Development of Lateral Flow Immunochromatographic Strips for Micropollutant Screening Using Colorants of Aptamer-Functionalized Nanogold Particles, Part II: Experimental Verification with Aflatoxin B1 and Chloramphenicol

2018 ◽  
Vol 101 (5) ◽  
pp. 1408-1414 ◽  
Author(s):  
Shan Zhang ◽  
Shuai Zhao ◽  
Sai Wang ◽  
Jiahui Liu ◽  
Yiyang Dong
Keyword(s):  
Aflatoxin B1 ◽  
Water Samples ◽  
Lateral Flow ◽  
Competitive Reaction ◽  
Immunochromatographic Strip ◽  
Detection Range ◽  
Nanogold Particles ◽  
Thiolated Aptamer ◽  
Cap Analysis ◽  
Optimized Conditions

Abstract Lateral flow immunochromatographic strips based on colorants of aptamer-functionalized nanogold particles were developed for the detection of micropollutants aflatoxin B1 (AFB1) and chloramphenicol (CAP). The lateral flow immunochromatographic strip was based on a competitive reaction of thiolated-aptamer between micropollutants and bio-DNA probe-streptavidin as capture material immobilized at the test line. General crucial parameters that might influence the sensitivity have been systematically investigated. To test the effectiveness and applicability of the optimized conditions, two structurally unrelated micropollutants, that is, AFB1 and CAP, were chosen for detection. In the present study, lateral flow immunochromatographic strips for AFB1 and CAP analysis by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogold in municipal water samples were reported for the first time. With the optimized conditions, the immunochromatographic strip showed a visual LOD of 10 ppb and a quantitative LOD of 1.05 ppb using an immunochromatographic reader for AFB1 detection and a quantitative LOD of 63.4 ppb using an immunochromatographic reader for CAP detection. Furthermore, the sensitive strip provided a good linear detection range of approximately 0–50 ppm for AFB1 detection and a wider liner detection range of approximately 0–160 ppm for CAP detection. Moreover, the immunochromatographic strip provided recovery rates for water samples of 90–110% in the AFB1 analysis and 84–108% in the CAP analysis. The results demonstrated that the immunochromatographic strip has excellent potential for wide applicability and verified that the strip methods for the optimized conditions are applicable to a variety of micropollutants. The lateral flow immunochromatographic strip could be used as a simple, rapid, and efficient screening tool for rapid on-site detection of a variety of micropollutants.

Development of Lateral Flow Immunochromatographic Strips for Micropollutants Screening Using Colorants of Aptamer Functionalized Nanogold Particles Part I Methodology and Optimization

2018 ◽  
Vol 101 (5) ◽  
pp. 1402-1407 ◽  
Author(s):  
Shuai Zhao ◽  
Shan Zhang ◽  
Sai Wang ◽  
Jiahui Liu ◽  
Yiyang Dong
Keyword(s):  
Reading Time ◽  
Limit Of Detection ◽  
Blocking Agent ◽  
Rapid Identification ◽  
Lateral Flow ◽  
Immunochromatographic Strip ◽  
Assay Performance ◽  
Nanogold Particles ◽  
Visual Limit ◽  
Optimized Conditions

Abstract A methodology of lateral flow immunochromatographic strip based on aptamer was developed for on-site detection of the small molecule micropollutants. In the present study, we try for the first time to investigate the feasibility of developing a strip assay for the analysis of micropollutants as methodological prototypes by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogolds. This quantitative method was based on the competition for the aptamer between targets and DNA probes. Crucial parameters that might influence the sensitivity, such as the size of nanogolds, amount of aptamer, type and pH of streptavidin, type of nitrocellulose (NC) membrane, blocking procedure, and reading time, were systematically investigated to obtain the optimum assay performance. With the optimized conditions [nanogolds 25 nm, 50 μM aptamer, pH 8 of GSA (a type of streptavidin named “SA Gold,” which is a sulfhydrylization streptavidin), Millipore HFC 135 NC membrane, 1% bovine serum albumin as the blocking agent and added in the running buffer and sample pad soakage agents, and 20 min reading time] the aptamer-based lateral flow assay will show a low visual limit of detection and scanning reader LOD. The strip for on-site screening using colorants of aptamer functionalized nanogold particles did not require any complicated equipment and was a potential portable tool for rapid identification of micropollutants.

scholarly journals Developing Gold Nanoparticles-Conjugated Aflatoxin B1 Antifungal Strips

2019 ◽  
Vol 20 (24) ◽  
pp. 6260 ◽  
Author(s):  
Tobiloba Sojinrin ◽  
Kangze Liu ◽  
Kan Wang ◽  
Daxiang Cui ◽  
Hugh J. Byrne ◽  
...  
Keyword(s):  
Detection Limit ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Point Of Care ◽  
Colour Change ◽  
Food Samples ◽  
Lateral Flow ◽  
Resonance Spectroscopy ◽  
Immunochromatographic Strip ◽  
Specificity And Sensitivity

Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests, based on their simplicity, specificity, and sensitivity. In this study, a rapid and sensitive gold nanoparticle (AuNP) immunochromatographic strip is produced for detecting aflatoxin B1 (AFB1) in suspicious fungi-contaminated food samples. The 10 nm AuNPs were encompassed by bovine serum albumin (BSA) and AFB1 antibody. Thin-layer chromatography, gel electrophoresis and nuclear magnetic resonance spectroscopy were employed for analysing the chemical complexes. Various concentrations of AFB1 antigen (0–16 ng/mL) were tested with AFB1 antibody–BSA–AuNPs (conjugated AuNPs) and then analysed by scanning electron microscopy, ultraviolet–visible spectroscopy, and Zetasizer. The results showed that the AFB1 antibody was coupled to BSA by the N-hydroxysuccinimide ester method. The AuNPs application has the potential to contribute to AFB1 detection by monitoring a visible colour change from red to purple-blue, with a detection limit of 2 ng/mL in a 96-well plate. The lateral flow immunochromatographic strip tests are rapid, taking less than 10 min., and they have a detection capacity of 10 ng/g. The smartphone analysis of strips provided the results in 3 s, with a detection limit of 0.3 ng/g for AFB1 when the concentration was below 10 ng/g. Excellent agreement was found with AFB1 determination by high-performance liquid chromatography in the determination of AFB1 among 20 samples of peanuts, corn, rice, and bread.

scholarly journals Label-Free Capacitive Biosensor for Detection of Cryptosporidium

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 258 ◽  
Author(s):  
George Luka ◽  
Ehsan Samiei ◽  
Soroush Dehghani ◽  
Thomas Johnson ◽  
Homayoun Najjaran ◽  
...  
Keyword(s):  
Water Samples ◽  
Fluorescein Isothiocyanate ◽  
Environmental Water ◽  
Immunofluorescence Assay ◽  
Label Free ◽  
Intestinal Protozoan ◽  
Detection Range ◽  
Cryptosporidium Oocysts ◽  
Capacitive Biosensor ◽  
Optimized Conditions

Cryptosporidium, an intestinal protozoan pathogen, is one of the leading causes of diarrhea in healthy adults and death in children. Detection of Cryptosporidium oocysts has become a high priority to prevent potential outbreaks. In this paper, a label-free interdigitated-based capacitive biosensor has been introduced for the detection of Cryptosporidium oocysts in water samples. Specific anti-Cryptosporidium monoclonal antibodies (IgG3) were covalently immobilized onto interdigitated gold electrodes as the capture probes, and bovine serum albumin was used to avoid non-specific adsorption. The immobilization of the antibodies was confirmed by measuring the change in the contact angle. The detection was achieved by measuring the relative change in the capacitive/dielectric properties due to the formation of Cryptosporidium-antibody complex. The biosensor has been tested for different concentrations of Cryptosporidium. The results show that the biosensor developed can accurately distinguish different numbers of captured cells and densities on the surface of the biosensor. The number of Cryptosporidium oocysts captured on the electrode surface was confirmed using a fluorescein isothiocyanate (FITC) immunofluorescence assay. The response from the developed biosensor has been mainly dependent on the concentration of Cryptosporidium under optimized conditions. The biosensor showed a linear detection range between 15 and 153 cells/mm2 and a detection limit of 40 cells/mm2. The label-free capacitive biosensor developed has a great potential for detecting Cryptosporidium in environmental water samples. Furthermore, under optimized conditions, this label-free biosensor can be extended for detection of other biomarkers for biomedical and environmental analyses.

scholarly journals Determination of ultra-trace levels of palladium in water samples by cloud point extraction and graphite furnace atomic absorption spectrometry

2021 ◽  
pp. 174751982110273
Author(s):  
Quan Han ◽  
Yanyan Huo ◽  
Xiaohui Yang ◽  
Xing Yao
Keyword(s):  
Water Samples ◽  
Cloud Point Extraction ◽  
Graphite Furnace ◽  
Chelating Agent ◽  
Absorption Spectrometry ◽  
Graphite Furnace Atomic Absorption ◽  
Ultra Trace ◽  
Triton X ◽  
Optimized Conditions

A highly sensitive method for the determination of ultra-trace levels of palladium in water samples by cloud point extraction and graphite furnace atomic absorption spectrometry is developed. The procedure is based on complexation of palladium with a laboratory-prepared novel chelating agent, 2-(5-bromo-4-methyl-2-pyridylazo)-5-dimethylaminoaniline (5-Br-4-CH3-PADMA) and subsequent micelle-mediated extraction of the product using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as an extracting agent. Analytical parameters affecting the separation and detection process, such as pH, concentration of the chelating agent and surfactant, equilibration temperature, and time are investigated. The optimized conditions are as follows: pH 6.0 HAc–NaAc buffer solution, 1 × 10−5 mol L−1 5-Br-4-CH3-PADMA, and 0.1% (w/v) Triton X-114. Under the optimized conditions, the calibration graph is linear in the range of 0.1–12 ng/mL, the detection limit is 0.05 ng/mL for palladium, and the relative standard deviation is 2.9% ( c = 1.0 ng/mL, n = 10). The enrichment factor, defined as the ratio of the aqueous solution volume to that of the surfactant-rich phase volume after dilution with HNO3–methanol solution, is 200. The proposed method is applied to the determination of palladium in water samples with satisfactory results.

scholarly journals Carbon Quantum Dots Encapsulated Molecularly Imprinted Fluorescence Quenching Particles for Sensitive Detection of Zearalenone in Corn Sample

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 438 ◽  
Author(s):  
Manyu Shao ◽  
Ming Yao ◽  
Sarah De Saeger ◽  
Liping Yan ◽  
Suquan Song
Keyword(s):  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Sol Gel ◽  
Carbon Quantum Dots ◽  
Detection Range ◽  
Molecularly Imprinted ◽  
Relative Standard ◽  
Sol Gel Process ◽  
One Step ◽  
Optimized Conditions

An eco-friendly and efficient one-step approach for the synthesis of carbon quantum dots (CDs) that encapsulated molecularly imprinted fluorescence quenching particles (MIFQP) and their application for the determination of zearalenone (ZEA) in a cereal sample are described in this study. CDs with high luminescence were first synthesized, and then encapsulated in the silica-based matrix through a non-hydrolytic sol-gel process. The resulting ZEA-imprinted particles exhibited not only an excellent specific molecular recognition of ZEA, but also good photostability and obvious template binding-induced fluorescence quenching. Under the optimized conditions, the fluorescence intensity of MIFQP was inversely proportional to the concentration of ZEA. By validation, the detection range of these fluorescence quenching materials for ZEA was between 0.02 and 1.0 mg L−1, and the detection limit was 0.02 mg L−1 (S/N = 3). Finally, the MIFQP sensor was successfully applied for ZEA determination in corn with recoveries from 78% to 105% and the relative standard deviation (RSD %) was lower than 20%, which suggests its potential in actual applications.

A lateral flow assay for simultaneous detection of Deoxynivalenol, Fumonisin B1 and Aflatoxin B1

Toxicon ◽  
2018 ◽  
Vol 156 ◽  
pp. 23-27 ◽  
Author(s):  
Songcheng Yu ◽  
Leiliang He ◽  
Fei Yu ◽  
Lie Liu ◽  
Chenling Qu ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Simultaneous Detection ◽  
Fumonisin B1 ◽  
Lateral Flow ◽  
Lateral Flow Assay
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