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Data on characterization and validation of assays for ultrasensitive quantitative detection of small molecules: Determination of free thyroxine with magnetic and interferometric methods
摘要： The presented data refer to optimization and quantitative characterization of a rapid lateral flow assay based on high-affinity bifunctional ligand and magnetic nanolabels, which was developed for detection of small molecules of thyroid hormones. The results were obtained by including the magnetic particle quantification method, spectral-correlation interferometry and spectral-phase interferometry, dynamic light scattering, enzyme linked immunosorbent assay. The long-term stability of "antibody – magnetic nanoparticle" conjugates is shown. The assay specificity is confirmed, and verification of successful combination of magnetic particles and antibodies is demonstrated. The kinetic and equilibrium dissociation constants are determined for interactions between thyroxine and monoclonal antibodies. The obtained data could be used for design of other platforms for detection of small molecules.
关键词： ELISA,Lateral flow assay,Small molecules,Ultrasensitive detection,Free thyroxine,Interferometry,Magnetic nanolabels,Dynamic light scattering
更新于2025-09-23 15:22:29
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eLISA Telescope In-field Pointing and Scattered Light Study
摘要： The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately ± one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (“backlink” fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance.
关键词： telescope,eLISA,in-field pointing,gravitational wave,scattered light
更新于2025-09-23 15:19:57
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Silver nanoprisms based plasmonic ELISA for sensitive detection of fluoroquinolones
摘要： Fluoroquinolones are synthetic antibiotics that are commonly used in animal husbandry, and the consumption of animal products with fluoroquinolone residues has imposed serious threat to human health. Here, we report a plasmonic enzyme-linked immunosorbent assay (pELISA) method based on oxidative etching of silver nanoprism (AgNPR) for the quantitative and qualitative detection of danofloxacin (DAN), a fluoroquinolone antibiotic. AgNPRs that undergo colorimetric changes upon oxidative etching by H2O2 serve as the signal transducer in our design. The indirect competitive pELISA was constructed by introducing biotinylated monoclonal antibody (mAb), streptavidin and biotinylated glucose oxidase, which catalyzes the generation of H2O2 for etching AgNPRs. The quantitative detection limit of the proposed method was 0.24 ng/mL for DAN. The qualitative detection limit for DAN reached 0.32 ng/mL, which was 32-fold lower than that of the assay using 3, 3’, 5, 5’-Tetramethylbenzidine (TMB) as the signal transducer. The average recoveries of DAN in milk ranged from 103% to 121%, with a coefficient of variation of 0.6% - 3.41%. The recovery results were further confirmed using liquid chromatography-tandem mass spectrometry. In summary, the proposed AgNPR etching pELISA produces high sensitivity, good accuracy and excellent reliability for the quantitative and qualitative detection of DAN in milk.
关键词： Glucose oxidase,Quantitative and qualitative detection,Fluoroquinolones,Plasmonic ELISA,Danofloxacin,Triangular silver nanoprism
更新于2025-09-19 17:13:59
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Highly Sensitive Detection of Salbutamol by ALP-mediated Plasmonic ELISA Based on Controlled Growth of AgNPs
摘要： Salbutamol (SAL), a short-acting β-2 adrenergic receptor agonist, is an undesirable addition to livestock farming and used to improve the growth rates. A direct competitive colorimetric immunoassay for SAL was developed. The alkaline phosphatase (ALP)-mediated controlled growth of the prereduction silver nanoparticles (AgNPs) was used to achieve the highly sensitive, colorimetric detection of SAL through the plasmonic ELISA. Click chemistry reaction was used to synthesize salbutamol biotin label (SAL-Bio) to achieve signal amplification and specific binding with antibody. ALP can efficiently hydrolyze sodium L-ascorbyl-2-phosphate and generate L-ascorbic acid, thereby reducing Ag+ and forming AgNPs. The plasmon resonance absorption signals of AgNPs were enhanced along with a distinct color change. The limit of detection of SAL can be decreased to 26.14 pg/mL. The method offers a good technique for the detection of many small molecular contaminants, such as pesticide residues and veterinary drug residues in food and edible water.
关键词： Salbutamol,alkaline phosphatase,colorimetric detection,direct competitive immunoassay,plasmonic ELISA,silver nanoparticles
更新于2025-09-19 17:13:59
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A Fast and Reproducible ELISA Laser Platform for Ultrasensitive Protein Quantification
摘要： Optofluidic lasers are currently of high interest for sensitive, intra-cavity, biochemical analysis. In comparison with conventional methods such as fluorescence and colorimetric detection, optofluidic lasers provide a method for amplifying small concentration differences in the gain medium, thus achieving high sensitivity. Here we report the development of an on-chip ELISA (enzyme-linked immunosorbent assay) laser platform that is able to complete an assay in short amount of time with small sample/reagent volumes, large dynamic range, and high sensitivity. The arrayed micro-scale reaction wells in the ELISA lasers can be microfabricated directly on dielectric mirrors, thus significantly improving the quality of the reaction wells and detection reproducibility. The details of the fabrication and characterization of those reaction wells on the mirror are described and the ELISA laser assay protocols are developed. Finally, we applied the ELISA laser to detecting IL-6, showing that a detection limit of about 0.1 pg/mL can be achieved in 1.5 hours with 15 μL of sample/reagents per well. This work pushes the ELISA laser a step closer to solving problems in real-world biochemical analysis.
关键词： Interleukin-6,Fabry-Perot cavity,Immunoassay,Optofluidic laser,Microfabrication,ELISA
更新于2025-09-12 10:27:22
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Classification of aflatoxin contaminated single Corn kernels by Ultraviolet to near Infrared spectroscopy
摘要： Aflatoxin contamination in corn poses threats to consumer food safety and grower economic stability. Current industrial methods for aflatoxin management in corn focus on the bulk aflatoxin level, which can lead to either acceptance of lots with contaminated corn kernels (consumer food safety risk) or rejection of lots with mostly harmless corn kernels (grower economic loss). This dilemma may be resolved by utilizing spectroscopy to classify single corn kernels. Hence, our research aims to investigate the potential of using a custom-built UltraViolet-Visible-Near InfraRed spectroscopy system (UV-Vis-NIR) to classify single corn kernels by aflatoxin level. Single kernels from cobs inoculated with aflatoxin-producing Aspergillus flavus (240 kernels) and uninoculated cobs (240 kernels) were i) scanned individually for reflectance from 304 nm to 1,086 nm by an increment of 0.5 nm; ii) ground; iii) measured for aflatoxin by ELISA. Using the spectra and the aflatoxin concentration, a random forest model was trained on 80% of the kernels to classify single corn kernels above or below 20 ppb of aflatoxin and was tested on the remaining 20% of the kernels. Among 480 kernels, 374 kernels had < 20 ppb of aflatoxin and 106 kernels had ≥ 20 ppb of aflatoxin. The random forest model had a sensitivity of 87.1% and specificity of 97.7% in the training set and a sensitivity of 85.7% and specificity of 97.3% in the test set, which is higher than previous models where kernels were in motion and comparable to models where kernels were stationary. Spectral regions around 390, 540, and 1,050 nm are found to be important for classification. This study demonstrated the custom-built UV-Vis-NIR spectroscopy system showed considerable potential in classifying single corn kernels by aflatoxin level while the kernels are in motion.
关键词： ELISA,Spectroscopy,Classification,Aflatoxin,Corn,Random forest
更新于2025-09-09 09:28:46
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Development of a surface plasmon resonance immunosensor and ELISA for 3-nitrotyrosine in human urine
摘要： 3-Nitrotyrosine (3-NT) is thought to be a relevant biomarker of nitrosative stress which is associated with many inflammatory and chronic diseases. It is necessary to develop confidential method for specific and sensitive 3-NT detection. In this paper, on the basis of anti-3-NT specific antibody, we developed a label-free indirect competitive surface plasmon resonance (SPR) immunosensor and ELISA for the detection of 3-NT. Under the optimized conditions, the SPR immunosensor can obtain a linear range of 0.17–6.07 μg/mL and a limit of detection (LOD) of 0.12 μg/mL while the ELISA can reach 0.33–9.94 μg/mL and a LOD of 0.24 μg/mL.The selectivity of 3-NT was also testified by six kinds of amino acid analogues. Besides, the developed SPR immunosensor was compared thoroughly with a conventional ELISA in spiked analysis of urine samples. Good recoveries and correlation between these two methods were observed (R2 = 0.964). Therefore, it is concluded that the automated SPR platform can be applied to quantify 3-NT in biological samples with its sensitivity, accuracy, and real-timing.
关键词： ELISA,Human urine,3-nitrotyrosine,Surface plasmon resonance (SPR)
更新于2025-09-09 09:28:46