scholarly journals Luciferase Immunoprecipitation Systems immunoassay is a sensitive, rapid method to detect allergen component-specific IgE

2020 ◽  
Author(s):  
Adora A. Lin ◽  
Natalia S. Perez ◽  
Pamela A. Frischmeyer-Guerrerio ◽  
Thomas B. Nutman
Keyword(s):  
Dynamic Range ◽  
Specific Ige ◽  
Turnaround Time ◽  
Sample Volume ◽  
Small Sample ◽  
Flexible Tool ◽  
Allergen Component ◽  
Fel D 1 ◽  
Broad Dynamic Range ◽  
Allergen Extracts

AbstractCurrent assays to detect allergen-specific IgE have constraints related to obtaining pure, conformationally active allergen, variability in allergen extracts, sample volume required, and turnaround time. The luciferase immunoprecipitation systems (LIPS) immunoassay is a fast, sensitive assay created using recombinant antigens that requires a low specimen volume. These assays can also be easily modified to detect multiple antigens and antibody isotypes. Here, we demonstrate the use of LIPS assays as an innovative method to quantitatively measure allergen component-specific IgE in small sample volumes. Sera from healthy volunteers, helminth-infected adults, and peanut-allergic children were screened for IgE to cat using ImmunoCAP. These samples were also measured for IgE against Fel d 1 using LIPS. LIPS signal correlated to cat IgE levels with rS = 0.6204, p < 0.001. The LIPS signal: noise ratio differed significantly between cat IgE-samples and cat IgE+ samples with values > 0.5 kU/L, with the ability to differentiate cat IgE – individuals from cat IgE+ individuals with 85% sensitivity and 76% specificity. Given their rapidity, efficiency, sensitivity, and quantitation over a broad dynamic range, LIPS immunoassays can be a robust and flexible tool with potential uses in allergy research, diagnostics, and treatment.

scholarly journals A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

2021 ◽  
Author(s):  
Fanda Meng ◽  
Weisong Huo ◽  
Jie Lian ◽  
Lei Zhang ◽  
Xizeng Shi ◽  
...  
Keyword(s):  
Detection Limit ◽  
Giant Magnetoresistance ◽  
Dynamic Range ◽  
Point Of Care ◽  
Sample Volume ◽  
Small Sample ◽  
Broad Dynamic Range ◽  
Gmr Sensors ◽  
Gmr Sensor ◽  
Sample Volume Requirement

AbstractWe report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 μL), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

Microflow UPLC and high-resolution MS as a sensitive and robust platform for quantitation of intact peptide hormones

Bioanalysis ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 1275-1289 ◽  
Author(s):  
Zhuo Chen ◽  
Yun W Alelyunas ◽  
Mark D Wrona ◽  
Jonathan R Kehler ◽  
Matthew E Szapacs ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Peptide Hormones ◽  
Ultra Performance Liquid Chromatography ◽  
Sample Volume ◽  
Mass Spectrometers ◽  
Broad Dynamic Range ◽  
Comparable Performance ◽  
Increased Sensitivity ◽  
Higher Sensitivity

Aim: Recent advances in microflow ultra performance liquid chromatography (UPLC) systems offer higher sensitivity with robustness to meet the routine bioanalytical demands. Modern high-resolution mass spectrometers (HRMS) enable the development of highly selective methods with broad dynamic range. Results: The quantitative performances of tandem quadrupole MS and HRMS were comprehensively compared using seven intact peptide hormones up to 9.4 kDa. Results show comparable performance between two platforms in sensitivity, accuracy and linearity. For some peptides, HRMS provided lower background interference. The benefit of increased sensitivity using microflow UPLC was also demonstrated. Conclusion: HRMS is a versatile platform capable of both basic characterization and reliable quantitation in complex matrices. Microflow UPLC provides lower LLOQs than conventional flow systems, even with less sample volume injected.

scholarly journals Multiplex Assays of Luminex for Identification of COVID-19 Antibodies in Patient Serum: Performance Evaluation and Comparison to ELISA

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S92-S92
Author(s):  
M S Shapiro ◽  
X Wang ◽  
D R Mendu ◽  
A Firpo
Keyword(s):  
Dynamic Range ◽  
High Titer ◽  
Mount Sinai Hospital ◽  
Antibody Testing ◽  
Luminex Assay ◽  
Multiplex Assays ◽  
Negative Results ◽  
Broad Dynamic Range ◽  
Circulating Antibodies ◽  
Mount Sinai

Abstract Introduction/Objective Mount Sinai Hospital has received emergency use authorization (EUA) from the FDA for Coronavirus Disease 2019 (COVID-19) antibody testing using ELISA. This serological assay detects and titrates the presence of circulating antibodies to COVID-19. Other platforms have aimed to achieve the credentials of the ELISA instrument, including the multiplex assays of Luminex. The platform is known to have a greater throughput (384 wells vs. 96 wells per microplate) and faster processing speed (8 hours vs. 17 hours). Methods Luminex utilizes beads that couple to the same COVID-19 antigens (mRBD and mSpike) which were utilized for the ELISA assay. The beads are read determining the mean fluorescence intensity (MFI). In order to compare the two methods, our study included 61 patients with COVID-19 at Mount Sinai Hospital, to screen and titrate their sera using Luminex, and to correspond the MFI values with the ELISA titers. Results The Luminex assay has achieved the same level of confidence as ELISA. The 61 patients, representing 30 negatives and 31 positives, are consistently identified as such on both platforms. Our data highlights 32% of patients with a low titer (&lt;1:160), 42% of patients with a high titer (1:160 ~ 1:320), and 26% of patients with a very high titer level (&gt;1:320). These titers correlated well with the MFI values. Based on a cutoff of 80,000 MFI, the sensitivity and specificity of the assay is 98% and 85%, respectively, with no overlapping of MFI between positive and negative results. Conclusion Overall, the study has demonstrated that the Luminex is a strong alternative for the ELISA platform. The Luminex highlights the broad dynamic range with no overlapping between positives and negatives. Migration from ELISA to Luminex, a platform with faster and greater throughput, is therefore, highly desirable.

scholarly journals Analysis of Results of Specific IgE in 100 Atopic Dermatitis Patients with the Use of Multiplex Examination ALEX2—Allergy Explorer

2021 ◽  
Vol 22 (10) ◽  
pp. 5286
Author(s):  
Jarmila Čelakovská ◽  
Josef Bukač ◽  
Eva Cermákova ◽  
Radka Vaňková ◽  
Hana Skalská ◽  
...  
Keyword(s):  
Atopic Dermatitis ◽  
Arginine Kinase ◽  
Specific Ige ◽  
Protein Domain ◽  
Storage Mites ◽  
Fel D 1 ◽  
Analysis Of Results ◽  
Can F 1 ◽  
High Level ◽  
Molecular Components

Background and aim: Progress in laboratory diagnostics of IgE-mediated allergy is the use of component-resolved diagnosis. Our study analyses the results of specific IgE to 295 allergen reagents (117 allergenic extracts and 178 molecular components) in patients suffering from atopic dermatitis (AD) with the use of ALEX2 Allergy Explorer. Method: The complete dermatological and allergological examination, including the examination of the sensitization to molecular components with ALEX2 Allergy Explorer testing, was performed. The statistical analysis of results was performed with these methods: TURF (total unduplicated reach and frequency), best reach and frequency by group size, two-sided tests, Fisher’s exact test, and chi-square test (at an expected minimum frequency of at least 5). Results: Altogether, 100 atopic dermatitis patients were examined: 48 men, 52 women, the average age 40.9 years, min. age 14 years, max. age 67 years. The high and very high level of specific IgE was reached in 75.0% of patients to 18 molecular components: from PR-10 proteins (Aln g 1, Bet v 1, Cor a1.0103, Cor a1.0401, Fag s 1), lipocalin (Can f 1), NPC2 family (Der f 2, Der p 2), uteroglobin (Fel d 1), from Alternaria alternata (Alt a 1), Beta expansin (Lol p 1, Phl p 1), molecular components from Timothy, cultivated rye (Secc pollen) and peritrophin-like protein domain Der p 23. The high and very high level of specific IgE to other lipocalins (Fel d 7, Can f 4), to arginine kinase (Bla g 9, German cockroach), and to allergen extracts Art v (mugwort), and Cyn d (Bermuda grass) reached 52.0% of patients. The severity of AD is in significant relation to the sensitization to molecular components of storage mites (Gly d 2, Lep d 2—NPC2 family), lipocalins (Can f 1, Can f 2, Can f 4, and Can f 6), arginine kinase (Asp f 6, Bla g 9, Der p 20, Pen m 2), uteroglobin (Fel d 1, Ory c 3), Mn superoxide dismutase (Mala s 11), PR-10 proteins (Fag s 1, Mal d 1, Cor a 1.0401, Cor a 1.0103), molecular components of the peritrophin-like domain (Der p 21, Der p 23), and to Secc pollen. In the subgroup of patients suffering from bronchial asthma, the significant role play molecular components from house dust mites and storage mites (Lep d 2, Der p 2, Der f 2—NPC2 family), cysteine protease (Der p 1), peritrophin-like protein domain (Der p 21, Der p 23), enolase from Alternaria alternata (Alt a 6), and Beta expansin Phl p 1. Conclusion: The results of our study demonstrate the detailed profile of sensitization to allergens reagents (allergen extract and molecular components) in patients with atopic dermatitis. We show the significance of disturbed epidermal barrier, resulting in increased penetration of allergens. We confirmed the significant relationship between the severity of AD, the occurrence of bronchial asthma and allergic rhinitis, and high levels of specific IgE to allergen reagents. Our results may be important for regime measures and immunotherapy; Der p 23 shall be considered as an essential component for the diagnosis and specific immunotherapy of house dust mite allergy.

scholarly journals Universal Stokes’s nanomechanical viscometer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Komal Chaudhary ◽  
Pooja Munjal ◽  
Kamal P. Singh
Keyword(s):  
Electric Field ◽  
Real Time ◽  
Sample Volume ◽  
Capillary Waves ◽  
Small Sample ◽  
Medical Applications ◽  
Rapid Measurement ◽  
Single Lens ◽  
Universal Applicability ◽  
Small Sample Volume

AbstractAlthough, many conventional approaches have been used to measure viscosity of fluids, most methods do not allow non-contact, rapid measurements on small sample volume and have universal applicability to all fluids. Here, we demonstrate a simple yet universal viscometer, as proposed by Stokes more than a century ago, exploiting damping of capillary waves generated electrically and probed optically with sub-nanoscale precision. Using a low electric field local actuation of fluids we generate quasi-monochromatic propagating capillary waves and employ a pair of single-lens based compact interferometers to measure attenuation of capillary waves in real-time. Our setup allows rapid measurement of viscosity of a wide variety of polar, non-polar, transparent, opaque, thin or thick fluids having viscosity values varying over four orders of magnitude from $$10^{0}{-}10^{4}~\text{mPa} \, \text{s}$$ 10 0 - 10 4 mPa s . Furthermore, we discuss two additional damping mechanisms for nanomechanical capillary waves caused by bottom friction and top nano-layer appearing in micro-litre droplets. Such self-stabilized droplets when coupled with precision interferometers form interesting microscopic platform for picomechanical optofluidics for fundamental, industrial and medical applications.

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

scholarly journals Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Adam Jordan ◽  
Jenna Chandler ◽  
Joshua S. MacCready ◽  
Jingcheng Huang ◽  
Katherine W. Osteryoung ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Morphology ◽  
Dynamic Range ◽  
Enhanced Recovery ◽  
Downstream Processing ◽  
Crop Species ◽  
Content Type ◽  
Alternative Crop ◽  
Cell Harvesting ◽  
Broad Dynamic Range

ABSTRACT Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus PCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCE We show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this manner continue to grow rapidly at time scales similar to those of uninduced controls. To our knowledge, this is the first reported example of engineering the cell morphology of cyanobacteria or algae to make them more compatible with downstream processing steps that present economic barriers to their use as alternative crop species. Therefore, our results are a promising proof-of-principle for the use of morphology engineering to increase the cost-effectiveness of the mass cultivation of cyanobacteria for various sustainability initiatives.

scholarly journals Plasmonic substrates for multiplexed protein microarrays with femtomolar sensitivity and broad dynamic range

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Scott M. Tabakman ◽  
Lana Lau ◽  
Joshua T. Robinson ◽  
Jordan Price ◽  
Sarah P. Sherlock ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Protein Microarrays ◽  
Broad Dynamic Range

A FRET based pH probe with a broad working range applicable to referenced ratiometric dual wavelength and luminescence lifetime read out

2015 ◽  
Vol 51 (28) ◽  
pp. 6145-6148 ◽  
Author(s):  
Robert J. Meier ◽  
Johann M. B. Simbürger ◽  
Tero Soukka ◽  
Michael Schäferling
Keyword(s):  
Dynamic Range ◽  
Dual Wavelength ◽  
Luminescence Lifetime ◽  
Ph Sensing ◽  
Ph Probe ◽  
Broad Dynamic Range ◽  
Europium Chelate ◽  
Ratiometric Ph Sensing

A FRET system composed of a europium chelate and carboxynaphthofluorescein enables ratiometric pH sensing with an exceptionally broad dynamic range.

An Immunodiagnostic Assay for Quantitation of Specific IgE to the Major Pollen Allergen Component, Pas n 1, of the Subtropical Bahia Grass

2014 ◽  
Vol 165 (4) ◽  
pp. 219-228 ◽  
Author(s):  
Victoria L. Timbrell ◽  
Lindsay Riebelt ◽  
Claire Simmonds ◽  
Graham Solley ◽  
William B. Smith ◽  
...  
Keyword(s):  
Specific Ige ◽  
Pollen Allergen ◽  
Allergen Component ◽  
Bahia Grass
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