Fluorescence lifetime-based biosensing of zinc: Origin of the broad dynamic range

1995 ◽  
Vol 5 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Richard B. Thompson ◽  
Marcia W. Patchan
Keyword(s):  
Fluorescence Lifetime ◽  
Dynamic Range ◽  
Broad Dynamic Range

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 (<1:160), 42% of patients with a high titer (1:160 ~ 1:320), and 26% of patients with a very high titer level (>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 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.

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.

scholarly journals Construction of a Nanosensor for Non-Invasive Imaging of Hydrogen Peroxide Levels in Living Cells

Biology ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 430
Author(s):  
Amreen ◽  
Hayssam M. Ali ◽  
Mohammad Ahmad ◽  
Mohamed Z. M. Salem ◽  
Altaf Ahmad
Keyword(s):  
Hydrogen Peroxide ◽  
Real Time ◽  
Mammalian Cells ◽  
Dynamic Range ◽  
Resonance Energy ◽  
Living Cells ◽  
Stress Conditions ◽  
Live Cells ◽  
Cell Physiology ◽  
Broad Dynamic Range

Hydrogen peroxide (H2O2) serves fundamental regulatory functions in metabolism beyond the role as damage signal. During stress conditions, the level of H2O2 increases in the cells and causes oxidative stress, which interferes with normal cell growth in plants and animals. The H2O2 also acts as a central signaling molecule and regulates numerous pathways in living cells. To better understand the generation of H2O2 in environmental responses and its role in cellular signaling, there is a need to study the flux of H2O2 at high spatio–temporal resolution in a real-time fashion. Herein, we developed a genetically encoded Fluorescence Resonance Energy Transfer (FRET)-based nanosensor (FLIP-H2O2) by sandwiching the regulatory domain (RD) of OxyR between two fluorescent moieties, namely ECFP and mVenus. This nanosensor was pH stable, highly selective to H2O2, and showed insensitivity to other oxidants like superoxide anions, nitric oxide, and peroxynitrite. The FLIP-H2O2 demonstrated a broad dynamic range and having a binding affinity (Kd) of 247 µM. Expression of sensor protein in living bacterial, yeast, and mammalian cells showed the localization of the sensor in the cytosol. The flux of H2O2 was measured in these live cells using the FLIP-H2O2 under stress conditions or by externally providing the ligand. Time-dependent FRET-ratio changes were recorded, which correspond to the presence of H2O2. Using this sensor, real-time information of the H2O2 level can be obtained non-invasively. Thus, this nanosensor would help to understand the adverse effect of H2O2 on cell physiology and its role in redox signaling.

scholarly journals PCR-Free Detection of Long Non-Coding HOTAIR RNA in Ovarian Cancer Cell Lines and Plasma Samples

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2233
Author(s):  
Narshone Soda ◽  
Muhammad Umer ◽  
Navid Kashaninejad ◽  
Surasak Kasetsirikul ◽  
Richard Kline ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Dynamic Range ◽  
Cancer Cell Lines ◽  
Plasma Samples ◽  
Isolation And Purification ◽  
Non Coding Rna ◽  
Broad Dynamic Range ◽  
Long Non Coding Rna

Long non-coding RNA HOX transcript antisense intergenic RNA (HOTAIR) is one of the promising biomarkers that has widely been used in determining the stages of many cancers, including ovarian cancer. In cancer diagnostics, the two key analytical challenges for detecting long non-coding RNA biomarkers are i) the low concentration levels (nM to fM range) in which they are found and ii) the analytical method where broad dynamic range is required (four to six orders of magnitude) due to the large variation in expression levels for different HOTAIR RNAs. To meet these challenges, we report on a biosensing platform for the visual (colorimetric) estimation and subsequent electrochemical quantification of ovarian-cancer-specific HOTAIR using a screen-printed gold electrode (SPE-Au). Our assay utilizes a two-step strategy that involves (i) magnetic isolation and purification of target HOTAIR sequences and (ii) subsequent detection of isolated sequences using a sandwich hybridization coupled with horseradish peroxidase (HRP)-catalyzed reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. The assay achieved a detection limit of 1.0 fM HOTAIR in spiked buffer samples with excellent reproducibility (% RSD ≤ 5%, for n = 3). It was successfully applied to detect HOTAIR in cancer cell lines and a panel of plasma samples derived from patients with ovarian cancer. The analytical performance of the method was validated with standard RT-qPCR. We believe that the proof of concept assay reported here may find potential use in routine clinical settings for the screening of cancer-related lncRNAs.

scholarly journals Multitarget, quantitative nanoplasmonic electrical field-enhanced resonating device (NE2RD) for diagnostics

2015 ◽  
Vol 112 (32) ◽  
pp. E4354-E4363 ◽  
Author(s):  
Fatih Inci ◽  
Chiara Filippini ◽  
Murat Baday ◽  
Mehmet Ozgun Ozen ◽  
Semih Calamak ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Point Of Care ◽  
Medical Diagnostics ◽  
Clinical Samples ◽  
Label Free ◽  
Protein Biomarkers ◽  
Electrical Field ◽  
Color Changes ◽  
Sensing Platform ◽  
Broad Dynamic Range

Recent advances in biosensing technologies present great potential for medical diagnostics, thus improving clinical decisions. However, creating a label-free general sensing platform capable of detecting multiple biotargets in various clinical specimens over a wide dynamic range, without lengthy sample-processing steps, remains a considerable challenge. In practice, these barriers prevent broad applications in clinics and at patients’ homes. Here, we demonstrate the nanoplasmonic electrical field-enhanced resonating device (NE2RD), which addresses all these impediments on a single platform. The NE2RD employs an immunodetection assay to capture biotargets, and precisely measures spectral color changes by their wavelength and extinction intensity shifts in nanoparticles without prior sample labeling or preprocessing. We present through multiple examples, a label-free, quantitative, portable, multitarget platform by rapidly detecting various protein biomarkers, drugs, protein allergens, bacteria, eukaryotic cells, and distinct viruses. The linear dynamic range of NE2RD is five orders of magnitude broader than ELISA, with a sensitivity down to 400 fg/mL This range and sensitivity are achieved by self-assembling gold nanoparticles to generate hot spots on a 3D-oriented substrate for ultrasensitive measurements. We demonstrate that this precise platform handles multiple clinical samples such as whole blood, serum, and saliva without sample preprocessing under diverse conditions of temperature, pH, and ionic strength. The NE2RD’s broad dynamic range, detection limit, and portability integrated with a disposable fluidic chip have broad applications, potentially enabling the transition toward precision medicine at the point-of-care or primary care settings and at patients’ homes.

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