A rapid and accurate method for screening T-2 toxin in food and feed using competitive AlphaLISA

2021 ◽  
Vol 368 (6) ◽  
Author(s):  
Liwen Zhang ◽  
Qingyu Lv ◽  
Yuling Zheng ◽  
Xuan Chen ◽  
Decong Kong ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Accurate Method ◽  
Detection Methods ◽  
Cereal Crops ◽  
Detection Range ◽  
Highly Sensitive ◽  
Food And Feed ◽  
Good Repeatability ◽  
Feed Samples ◽  
Better Than

ABSTRACT T-2 is a common mycotoxin contaminating cereal crops. Chronic consumption of food contaminated with T-2 toxin can lead to death, so simple and accurate detection methods in food and feed are necessary. In this paper, we establish a highly sensitive and accurate method for detecting T-2 toxin using AlphaLISA. The system consists of acceptor beads labeled with T-2-bovine serum albumin (BSA), streptavidin-labeled donor beads and biotinylated T-2 antibodies. T-2 in the sample matrix competes with T-2-BSA for antibodies. Adding biotinylated antibodies to the test well followed by T-2 and T-2-BSA acceptor beads yielded a detection range of 0.03–500 ng/mL. The half-maximal inhibitory concentration was 2.28 ng/mL and the coefficient of variation was <10%. In addition, this method had no cross-reaction with other related mycotoxins. This optimized method for extracting T-2 from food and feed samples achieved a recovery rate of approximately 90% in T-2 concentrations as low as 1 ng/mL, better than the performance of a commercial ELISA kit. This competitive AlphaLISA method offers high sensitivity, good specificity, good repeatability and simple operation for detecting T-2 toxin in food and feed.

scholarly journals Development and Validation of a High Sensitivity Assay for Measuring p217 + tau in Cerebrospinal Fluid

2020 ◽  
Vol 77 (4) ◽  
pp. 1417-1430
Author(s):  
Gallen Triana-Baltzer ◽  
Kristof Van Kolen ◽  
Clara Theunis ◽  
Setareh Moughadam ◽  
Randy Slemmon ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Amyloid Β ◽  
High Sensitivity ◽  
Csf Biomarkers ◽  
Highly Sensitive ◽  
Good Potential ◽  
Low Levels ◽  
Good Differentiation ◽  
Development And Validation ◽  
Better Than

Background: Early and accurate detection and staging is critical to managing Alzheimer’s disease (AD) and supporting clinical trials. Cerebrospinal fluid (CSF) biomarkers for amyloid-β peptides, tau species, and various neurodegenerative and inflammatory analytes are leading the way in this regard, yet there is room for improved sensitivity and specificity. In particular tau is known to be present in many different fragments, conformations, and post-translationally modified forms. While the exact tau species that might best reflect AD pathology is unknown, a growing body of evidence suggests that forms with high levels of phosphorylation in the mid-region may be especially enriched in AD. Objective: Develop an assay for measuring p217tau in CSF. Methods: Here we describe the development and validation of a novel sELISA for measuring CSF tau species containing phosphorylation at threonines 212 & 217, aka p217 + tau, using the PT3 antibody. Results: While the analyte is present at extremely low levels the assay is sufficiently sensitive and specific to quantitate p217 + tau with excellent precision, accuracy, and dilution linearity, allowing good differentiation between diagnostic subgroups. The p217 + tau measurements appear to track AD pathology better than the commonly used p181tau epitope, suggesting superior diagnostic and staging performance. Finally, the assay can also be configured to differentiate antibody-bound versus antibody-free tau, and therefore can be used to measure target engagement by p217 + tau-targeting immunotherapeutics. Conclusion: The assay for measuring p217 + tau described here is highly sensitive, accurate, precise, dilution linear, and shows good potential for identifying and staging AD.

A confined carbon dot-based self-calibrated fluorescence probe for visible and high-sensitivity moisture readouts

2021 ◽  
Author(s):  
Zhong-Zheng Ding ◽  
Guang-Song Zheng ◽  
Qing Lou ◽  
Jiang-Fan Han ◽  
Meng-Yuan Wu ◽  
...  
Keyword(s):  
High Performance ◽  
Potential Role ◽  
Fluorescence Probe ◽  
Color Change ◽  
High Sensitivity ◽  
Confinement Effect ◽  
Detection Range ◽  
Fluorescence Color ◽  
Highly Sensitive ◽  
New Type

Abstract Excellent luminescent materials are essential for high-performance fluorescent nanosensors. Here, a new-type self-calibrated humidity sensor has been established through monitoring the fluorescent color change of carbon dots (CDs) confined in sodium hydroxide (CDs@NaOH). The CDs are prepared by a facile and rapid microwave assisted heating method using citric acid, urea, and NaOH as precursors. The confinement effect from NaOH has reduced the nonradiative transition and suppressed the aggregation-induced quenching of the CDs in solid. Compared with other sensors based on CD fluorescent visualization, the sensor has good linearity and wide humidity detection range from 6.9% to 95.4%. With the increased relative humidity, the fluorescence color of the sensor change from green to blue. The proposed sensing mechanism is due to the breaking and reforming of hydrogen bonds and proton transfer occurring at the CD-NaOH matrix interfaces. This finding suggests a potential role for the spatial confinement effect and may provide an avenue for developing highly sensitive humidity readouts.

scholarly journals A cationic quantum dot-based ratiometric fluorescent probe to visually detect berberine hydrochloride in human blood serums

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mingyang Liu ◽  
Xuejun Du ◽  
Ke Xu ◽  
Binwei Yan ◽  
Zaibi Fan ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Human Blood ◽  
Cetylpyridinium Chloride ◽  
High Sensitivity ◽  
Water Soluble ◽  
Detection Methods ◽  
Detection Range ◽  
Berberine Hydrochloride ◽  
Relative Standard ◽  
Ratiometric Fluorescent Probe

AbstractBerberine hydrochloride (BH) is an isoquinoline alkaloid normally used as drug to treat diseases. Compared with the traditional detection methods, the carbon quantum dots (CQDs) have better selectivity, high sensitivity, easy operation, and is inexpensive which could be widely utilized as fluorescent nanoprobes to detect various compounds quantificationally. And ratiometric fluorescent sensors conspicuously increase sensitivity and precision detection and improve quantification. In this work, we use water-soluble and fluorescent cationic carbon dots cetylpyridinium chloride monohydrate (CPC)-CQDs to connect with pinacyanol chloride (PC) and sodium tetraphenylborate (ST) as the ratiometric fluorescent probe to detect BH. The ratiometric fluorescent probe has high sensitivity towards alkaloids and metal ions, photochemical stability (60 min), and pH stability (from 6.0 to 8.0), with the detection range from 0 to 200 μM, and limit was as low as 57.35 nM. The accuracy of the method was verified by spiked recovery experiment in different human blood serums which were drawn from healthy adult volunteers to explore the practicability. The recoveries were in the range 94.34 to 105.48% with relative standard deviations (RSD) of 0.80 to 2.92%. In addition, we could observe that the fluorescence was gradually darkened, and the color turned yellow to realize the visual detection. It is expected that this work would open up a new strategy for detecting BH in the environment and human blood serums.

scholarly journals Development of a Tandem Repeat-Based Polymerase Chain Displacement Reaction Method for Highly Sensitive Detection of ‘Candidatus Liberibacter asiaticus’

2018 ◽  
Vol 108 (2) ◽  
pp. 292-298 ◽  
Author(s):  
Binghai Lou ◽  
Yaqin Song ◽  
Moytri RoyChowdhury ◽  
Chongling Deng ◽  
Ying Niu ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
High Sensitivity ◽  
Cost Effective ◽  
Detection Methods ◽  
Displacement Reaction ◽  
Candidatus Liberibacter Asiaticus ◽  
Highly Sensitive ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Polymerase Chain

Huanglongbing (HLB) is one of the most destructive diseases in citrus production worldwide. Early detection of HLB pathogens can facilitate timely removal of infected citrus trees in the field. However, low titer and uneven distribution of HLB pathogens in host plants make reliable detection challenging. Therefore, the development of effective detection methods with high sensitivity is imperative. This study reports the development of a novel method, tandem repeat-based polymerase chain displacement reaction (TR-PCDR), for the detection of ‘Candidatus Liberibacter asiaticus’, a widely distributed HLB-associated bacterium. A uniquely designed primer set (TR2-PCDR-F/TR2-PCDR-1R) and a thermostable Taq DNA polymerase mutant with strand displacement activity were used for TR-PCDR amplification. Performed in a regular thermal cycler, TR-PCDR could produce more than two amplicons after each amplification cycle. Sensitivity of the developed TR-PCDR was 10 copies of target DNA fragment. The sensitive level was proven to be 100× higher than conventional PCR and similar to real-time PCR. Data from the detection of ‘Ca. L. asiaticus’ with filed samples using the above three methods also showed similar results. No false-positive TR-PCDR amplification was observed from healthy citrus samples and water controls. These results thereby illustrated that the developed TR-PCDR method can be applied to the reliable, highly sensitive, and cost-effective detection of ‘Ca. L. asiaticus’.

scholarly journals Highly sensitive and full-genome interrogation of SARS-CoV-2 using multiplexed PCR enrichment followed by next-generation sequencing

2020 ◽  
Author(s):  
Chenyu Li ◽  
David N. Debruyne ◽  
Julia Spencer ◽  
Vidushi Kapoor ◽  
Lily Y. Liu ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Multiplex Pcr ◽  
High Sensitivity ◽  
Detection Methods ◽  
Next Generation ◽  
Rt Pcr ◽  
Copy Numbers ◽  
Virus Rna ◽  
Highly Sensitive ◽  
Generation Sequencing

AbstractMany detection methods have been used or reported for the diagnosis and/or surveillance of COVID-19. Among them, reverse transcription polymerase chain reaction (RT-PCR) is the most commonly used because of its high sensitivity, typically claiming detection of about 5 copies of viruses. However, it has been reported that only 47-59% of the positive cases were identified by some RT-PCR methods, probably due to low viral load, timing of sampling, degradation of virus RNA in the sampling process, or possible mutations spanning the primer binding sites. Therefore, alternative and highly sensitive methods are imperative. With the goal of improving sensitivity and accommodating various application settings, we developed a multiplex-PCR-based method comprised of 343 pairs of specific primers, and demonstrated its efficiency to detect SARS-CoV-2 at low copy numbers. The assay produced clean characteristic target peaks of defined sizes, which allowed for direct identification of positives by electrophoresis. We further amplified the entire SARS-CoV-2 genome from 8 to half a million viral copies purified from 13 COVID-19 positive specimens, and detected mutations through next generation sequencing. Finally, we developed a multiplex-PCR-based metagenomic method in parallel, that required modest sequencing depth for uncovering SARS-CoV-2 mutational diversity and potentially novel or emerging isolates.

scholarly journals High-Sensitivity Whispering Gallery Mode Humidity Sensor Based on Glycerol Microdroplet Volumetric Expansion

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1746
Author(s):  
Pauls Kristaps Reinis ◽  
Lase Milgrave ◽  
Kristians Draguns ◽  
Inga Brice ◽  
Janis Alnis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Free Space ◽  
Humidity Sensor ◽  
Low Cost ◽  
High Sensitivity ◽  
Whispering Gallery Mode ◽  
Whispering Gallery ◽  
Volumetric Expansion ◽  
Highly Sensitive ◽  
Good Repeatability

We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, as well as the use of a non-toxic and environmentally friendly liquid.

scholarly journals ELISA and Chemiluminescent Enzyme Immunoassay for Sensitive and Specific Determination of Lead (II) in Water, Food and Feed Samples

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 305
Author(s):  
Long Xu ◽  
Xiao-yi Suo ◽  
Qi Zhang ◽  
Xin-ping Li ◽  
Chen Chen ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Quantitative Measurement ◽  
High Sensitivity ◽  
Health Concerns ◽  
Specific Determination ◽  
Food And Feed ◽  
Sensitivity Specificity ◽  
Feed Samples ◽  
Chemiluminescent Enzyme Immunoassay

Lead is a heavy metal with increasing public health concerns on its accumulation in the food chain and environment. Immunoassays for the quantitative measurement of environmental heavy metals offer numerous advantages over other traditional methods. ELISA and chemiluminescent enzyme immunoassay (CLEIA), based on the mAb we generated, were developed for the detection of lead (II). In total, 50% inhibitory concentrations (IC50) of lead (II) were 9.4 ng/mL (ELISA) and 1.4 ng/mL (CLEIA); the limits of detection (LOD) were 0.7 ng/mL (ic-ELISA) and 0.1 ng/mL (ic-CLEIA), respectively. Cross-reactivities of the mAb toward other metal ions were less than 0.943%, indicating that the obtained mAb has high sensitivity and specificity. The recovery rates were 82.1%–108.3% (ic-ELISA) and 80.1%–98.8% (ic-CLEIA), respectively. The developed methods are feasible for the determination of trace lead (II) in various samples with high sensitivity, specificity, fastness, simplicity and accuracy.

Development and Testing of a Miniature Silicon Microgyroscope Prototype

2008 ◽  
Author(s):  
Dunzhu Xia ◽  
Bailing Zhou ◽  
Shourong Wang
Keyword(s):  
High Sensitivity ◽  
Open Loop ◽  
Detection Methods ◽  
Sense Mode ◽  
Zero Bias ◽  
Power Cost ◽  
Mode Detection ◽  
Bias Stability ◽  
Single Side ◽  
Better Than

A silicon microgyroscope with the structure of area-changing capacitor detection is adopted in this paper, and the quality factor of Silicon Microgyroscope sealed with CAN mental package working under the air pressure of 10 Pa is above 3000, so its sense mode detection essentially attains better linear performance and high sensitivity. Single side driving and single side detection methods are applied to make both vibrating amplitude and frequency highly stable in drive mode circuit, and open loop difference detection method is utilized to achieve high precision detection in sense mode circuit. A miniature prototype scheme based on PCB technology has been realized with volume size of 40mm¡ 40mm¡ 30mm and power cost of less than 300 mW. The testing results demonstrate that the useful and quadrate signal will not interact because of their phase decoupling. Under the condition of the scale factor of 9.6 mV/°/s, the zero bias stability attains below 28 ° /h with linearity coefficient less than 500 ppm and simulated bandwidth more than 100 Hz, which has been improved two orders of magnitude better than that at atmospheric pressure. The engineering work is evolving at present.

scholarly journals How to Deal with the Upcoming Challenges in GMO Detection in Food and Feed

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Sylvia R. M. Broeders ◽  
Sigrid C. J. De Keersmaecker ◽  
Nancy H. C. Roosens
Keyword(s):  
Cost Effective ◽  
Plant Genome ◽  
Detection Methods ◽  
Time Saving ◽  
Modern Agriculture ◽  
New Crops ◽  
Food And Feed ◽  
History Of ◽  
Near Future ◽  
Feed Samples

Biotech crops are the fastest adopted crop technology in the history of modern agriculture. The commercialisation of GMO is in many countries strictly regulated laying down the need for traceability and labelling. To comply with these legislations, detection methods are needed. To date, GM events have been developed by the introduction of a transgenic insert (i.e., promoter, coding sequence, terminator) into the plant genome and real-time PCR is the detection method of choice. However, new types of genetic elements will be used to construct new GMO and new crops will be transformed. Additionally, the presence of unauthorised GMO in food and feed samples might increase in the near future. To enable enforcement laboratories to continue detecting all GM events and to obtain an idea of the possible presence of unauthorised GMO in a food and feed sample, an intensive screening will become necessary. A pragmatic, cost-effective, and time-saving approach is presented here together with an overview of the evolution of the GMO and the upcoming needs.

High-sensitivity detection of gold labels by high-angle dark-field STEM imaging

1990 ◽  
Vol 48 (3) ◽  
pp. 892-893 ◽  
Author(s):  
Max T. Otten
Keyword(s):  
High Sensitivity ◽  
Dark Field ◽  
Bright Field ◽  
Backscattered Electron Imaging ◽  
Backscattered Electrons ◽  
Average Atomic Number ◽  
Highly Sensitive ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
High Sensitivity Detection

Labelling of antibodies with small gold probes is a highly sensitive technique for detecting specific molecules in biological tissue. Larger gold probes are usually well visible in TEM or STEM Bright-Field images of unstained specimens. In stained specimens, however, the contrast of the stain is frequently the same as that of the gold labels, making it virtually impossible to identify the labels, especially when smaller gold labels are used to increase the sensitivity of the immunolabelling technique. TEM or STEM Dark-Field images fare no better (Figs. 1a and 2a), again because of the absence of a clear contrast difference between gold labels and stain.Potentially much more useful is backscattered-electron imaging, since this will show differences in average atomic number which are sufficiently large between the metallic gold and the stains normally used. However, for the thin specimens and at high accelerating voltages of the STEM, the yield of backscattered electrons is very small, resulting in a very weak signal. Consequently, the backscattered-electron signal is often too noisy for detecting small labels, even for large spot sizes.

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