scholarly journals Lateral Flow Assay with Near-Infrared Dye for Multiplex Detection

2013 ◽  
Vol 59 (4) ◽  
pp. 641-648 ◽  
Author(s):  
Christina Swanson ◽  
Annalisa D'Andrea
Keyword(s):  
Near Infrared ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Test Strip ◽  
Lateral Flow ◽  
Diagnostic Tools ◽  
High Signal ◽  
Analytical Sensitivity ◽  
Robust Detection ◽  
Lateral Flow Assays

BACKGROUND Lateral flow assays (LFAs) are popular point-of-care diagnostic tools because they are rapid and easy to use. Nevertheless, they often lack analytical sensitivity and quantitative output and may be difficult to multiplex, limiting their usefulness in biomarker measurement. As a proof-of-concept study, we detail the design of a quantitative, multiplex LFA with readily available near-infrared (NIR) detection to improve analytical sensitivity. METHODS NIR dye was conjugated to selected antibodies and incorporated into LFAs. We used singleplex, optimized NIR-LFAs to measure interleukin (IL)-6 from 0 to 200 pg/mL and developed duplex assays to simultaneously measure IL-6 from 0 to 100 pg/mL (0 to 4.5 pmol/L) and C-reactive protein (CRP) from 50 to 2500 ng/mL (0.4 to 20 nmol/L) on a single test strip. Assays were tested on 60 different spiked samples and compared to ELISA results. RESULTS NIR-LFAs detected IL-6 in a 10% plasma matrix with a limit of detection of 4 pg/mL (182 fmol/L) and a CV <7%. Duplex NIR-LFAs quantitatively measured IL-6 and CRP concentrations simultaneously. Values strongly correlated to ELISA measurements, with R2 values of 0.9825 and 0.9711 for IL-6 and CRP, respectively. CONCLUSIONS NIR-LFAs exhibit quantitative measurement at pg/mL concentrations owing to a high signal-to-BACKGROUND ratio and robust detection antibody clearance through the test strip. Moreover, NIR-LFAs are able to detect molecules present at vastly different concentrations in multiplex format and compare favorably to ELISAs. LFAs with direct NIR detection may be a valuable tool for biomarker evaluation in the point-of-care setting.

Development of a Smartphone Based Reader for the Quantitative Analysis of Lateral Flow Assays

2018 ◽  
Vol 941 ◽  
pp. 2522-2527
Author(s):  
Sylvio Schneider ◽  
Martina Selig ◽  
Verena Keil ◽  
Matthias Lehmann ◽  
Andreas H. Foitzik ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Medical Devices ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Thrombotic Event ◽  
Lateral Flow ◽  
Proof Of Concept ◽  
Lateral Flow Assays ◽  
Further Development ◽  
D Dimer

Smartphones are developing into all-purposes devices. In the present work, the employment/application of smartphones as medical devices in home care and point-of-care (POC) diagnostics are investigated in the analysis of Lateral Flow Assays (LFA). A smartphone-based LFA reader was developed for the quantitative analysis of D-Dimer – a biomarker indicating e.g. thrombotic event or danger of embolism.The proof-of-concept has been shown with multiple smartphones in establishing: (I) Optimal dimensions of the LFA cell of 72.11mm distance of smartphone to D-Dimer test leading to a coefficients of variances (CV) between 0.8% and 4.2%. (II) Inter-device investigations: CVs around 13.5%; a limit of detection (LOD) of 100ng/ml (DDU) D-Dimer. (III) Inter-smartphone investigations: CV about 16%, a limit of detection (LOD) at 66.4ng/ml (DDU). (IV) Calibrations: CV and LOD of three smartphones are comparable to the commercial available LFA reader. Further development to put the multiple smartphone-based LFA reader on the market.

scholarly journals Development and Evaluation of Europium-Based Quantitative Lateral Flow Immunoassay for the Chronic Kidney Disease Marker Cystatin-C

2021 ◽  
Author(s):  
SATHEESH NATARAJAN ◽  
Ebru saatci
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Cystatin C ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Fluorescence Measurement ◽  
Analytical Sensitivity ◽  
Linear Calibration ◽  
Time Resolved

Abstract This study aimed to establish a Europium label time-resolved fluorescence immunoassay (TRFIA) to detect the chronic kidney disease (CKD) biomarker Cystatin-C. Some Cystatin-c immunoassays are sensitive, accurate, and available for clinical application, but they are expensive and time-consuming procedures. Also, conventional organic dye-based fluorescence lateral flow assay showed more background fluorescence interference and low analytical sensitivity. So this Europium-based sandwich immunoassay was developed to detect the concentration of cystatin-c in a urine sample with captured anti-cystatin-c antibodies immobilized on nitrocellulose membrane and then bonded with detection anti-cystatin-c labelled with CM-EU, followed by fluorescence measurement using time-resolved fluorometry in 15 minutes. The performance of this TRFIA was evaluated using the clinical urine serum and compared with the ELISA assays. The linear calibration range was 0.015-32 µg/ml, and the limit of detection (LOD) quantified was 0.0001µg/ml. This current work has improved the LOD of our previous work from 0.013µg/ml to 0.001µg/ml. These results indicated that the CM-EU nanoparticle-based LFIA is rapid, more sensitive, reliable, and reproducible for point-of-care testing of Cys-C concentrations in urine

scholarly journals Evaluation of accuracy, exclusivity, limit-of-detection and ease-of-use of LumiraDx™ - Antigen-detecting point-of-care device for SARS-CoV-2

2021 ◽  
Author(s):  
Lisa Johanna Krüger ◽  
Julian A.F. Klein ◽  
Frank Tobian ◽  
Mary Gaeddert ◽  
Federica Lainati ◽  
...  
Keyword(s):  
Viral Load ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Scale Up ◽  
Cross Reactivity ◽  
Ease Of Use ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Clinical Sensitivity ◽  
Lateral Flow Assays

Background: Rapid antigen-detecting tests (Ag-RDTs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transform pandemic control. Thus far, sensitivity (≤85%) of lateral-flow assays has limited scale-up. Conceivably, microfluidic immunofluorescence Ag-RDTs could increase sensitivity for SARS-CoV-2 detection. Materials and Methods: This multi-centre diagnostic accuracy study investigated performance of the microfluidic immunofluorescence LumiraDx™ assay, enrolling symptomatic and asymptomatic participants with suspected SARS-CoV-2 infection. Participants collected a supervised nasal mid-turbinate (NMT) self-swab for Ag-RDT testing, in addition to a professionally-collected nasopharyngeal (NP) swab for routine testing with reverse transcriptase polymerase chain reaction (RT-PCR). Results were compared to calculate sensitivity and specificity. Sub-analyses investigated the results by viral load, symptom presence and duration. An analytical study assessed exclusivity and limit-of-detection (LOD). In addition, we evaluated ease-of-use. Results: Study conduct was between November 2nd 2020 and January 21st 2021. 761 participants were enrolled, with 486 participants reporting symptoms on testing day. 120 out of 146 RT-PCR positive cases were detected positive by LumiraDx™, resulting in a sensitivity of 82.2% (95% CI: 75.2%-87.5%). Specificity was 99.3% (CI: 98.3-99.7%). Sensitivity was increased in individuals with viral load ≥ 7 log10 SARS-CoV2 RNA copies/ml (93.8%; CI: 86.2%-97.3%). Testing against common respiratory commensals and pathogens showed no cross-reactivity and LOD was estimated to be 2-56 PFU/mL. The ease-of-use-assessment was favourable for lower throughput settings. Conclusion: The LumiraDx™ assay showed excellent analytical sensitivity, exclusivity and clinical specificity with good clinical sensitivity using supervised NMT self-sampling.

scholarly journals Comparative assessment of multiple COVID-19 serological technologies supports continued evaluation of point-of-care lateral flow assays in hospital and community healthcare settings

2020 ◽  
Author(s):  
Suzanne Pickering ◽  
Gilberto Betancor ◽  
Rui Pedro Galão ◽  
Blair Merrick ◽  
Adrian W. Signell ◽  
...  
Keyword(s):  
Point Of Care ◽  
Antibody Test ◽  
Lateral Flow ◽  
Diagnostic Tools ◽  
Antibody Testing ◽  
Community Healthcare ◽  
Diagnostic Assays ◽  
Healthcare Settings ◽  
Lateral Flow Assays ◽  
Diagnostic Capabilities

AbstractThere is a clear requirement for an accurate SARS-CoV-2 antibody test, both as a complement to existing diagnostic capabilities and for determining community seroprevalence. We therefore evaluated the performance of a variety of antibody testing technologies and their potential as diagnostic tools. A highly specific in-house ELISA was developed for the detection of anti-spike (S), -receptor binding domain (RBD) and -nucleocapsid (N) antibodies and used for the cross-comparison of ten commercial serological assays – a chemiluminescence-based platform, two ELISAs and seven colloidal gold lateral flow immunoassays (LFIAs) – on an identical panel of 110 SARS-CoV-2-positive samples and 50 pre-pandemic negatives. There was a wide variation in the performance of the different platforms, with specificity ranging from 82% to 100%, and overall sensitivity from 60.9% to 87.3%. However, the head-to-head comparison of multiple sero-diagnostic assays on identical sample sets revealed that performance is highly dependent on the time of sampling, with sensitivities of over 95% seen in several tests when assessing samples from more than 20 days post onset of symptoms. Furthermore, these analyses identified clear outlying samples that were negative in all tests, but were later shown to be from individuals with mildest disease presentation. Rigorous comparison of antibody testing platforms will inform the deployment of point-of-care technologies in healthcare settings and their use in the monitoring of SARS-CoV-2 infections.

scholarly journals Rapid Detection of Hepatitis B Virus in Blood Samples Using a Combination of Polymerase Spiral Reaction With Nanoparticles Lateral-Flow Biosensor

2021 ◽  
Vol 7 ◽  
Author(s):  
Lin Lin ◽  
Jinshuai Guo ◽  
Haiyang Liu ◽  
Xiaofeng Jiang
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Diagnostic Technique ◽  
Lamp Assay ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Nucleic Acid Amplification ◽  
Analytical Sensitivity ◽  
Blood Samples ◽  
Nucleic Acid Amplification Technology

A rapid, highly sensitive, and robust diagnostic technique for point-of-care (PoC) testing can be developed using the combination of the nanoparticle-based lateral flow biosensors (LFB) and isothermal nucleic acid amplification technology. Here, we developed a polymerase spiral reaction (PSR) containing FITC-labeled DNA probes coupled with the nanoparticle-based LFB assay (PSR-LFB) to detect the amplified products to detect HBV visually. Under the optimized conditions, the PSR assay involved incubation of the reaction mixture for 20 min at 63°C, followed by visual detection of positive amplicons using LFB, which would generate a red test line based on the biotin/streptavidin interaction and immunoreactions, within 5 min. A cross-reactivity test revealed that the developed PSR-LFB assay showed good specificity for HBV and could distinguish HBV from other pathogenic microorganisms. For the analytical sensitivity, the limit of detection (LoD) of PSR-LFB assay was recorded as 5.4 copies/mL of HBV genomic DNA, which was ten-times more sensitive than qPCR and loop-mediated isothermal amplification (LAMP). Additionally, all the HBV-positive (29/82) samples, identified using ELISA, were also successfully detected by the PSR-LFB assay. We found that the true positive rate of the PSR-LFB assay was higher than that of qPCR (100 vs. 89.66%, respectively), as well as the LAMP assay (100 vs. 96.55%, respectively). Furthermore, the integrated procedure could be completed in 60 min, including the processing of the blood samples (30 min), an isothermal reaction (20 min), and result visualization (5 min). Thus, this PSR-LFB assay could be a potentially useful technique for PoC diagnosis of HBV in resource-limited countries.

scholarly journals A SARS-CoV-2 Coronavirus Nucleocapsid Protein Antigen-Detecting Lateral Flow Assay

2020 ◽  
Author(s):  
Ben D Grant ◽  
Caitlin E Anderson ◽  
Spencer H Garing ◽  
Luis F Alonzo ◽  
John R Williford ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Rapid Diagnostics ◽  
Rt Pcr ◽  
Efficient Detection ◽  
Lateral Flow Assays ◽  
Optical Reader ◽  
Polymerase Chain

<p></p><p>Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment and mitigation of COVID‑19. Currently, the primary diagnostic tool being utilized is reverse transcription polymerase chain reaction (RT-PCR). RT-PCR delivers results with good sensitivity and excellent specificity, but is expensive, prone to access challenges and is often slowed by transport to centralized testing laboratories. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed, with lateral flow assays (LFAs) being the most common inexpensive antigen test. To date, few antigen-detecting LFAs for COVID-19 have been commercialized. Herein, we present an open source LFA using commercially available antibodies and materials for the detection of SARS-CoV-2. Using an optical reader with comparable sensitivity to a visual read, the LFA yielded a Limit of Detection (LOD) of 23 TCID<sub>50</sub>/mL (95% CI of 9.1 to 37 TCID<sub>50</sub>/mL), equivalent to 1.4x10<sup>5</sup> copies/mL (95% CI of 5.5x10<sup>4</sup> to 2.3x10<sup>5</sup> copies/mL) irradiated virus in pooled nasal matrix. This LOD meets the criteria suggested by WHO for diagnosis of acute SARS-CoV-2 infection in a point of care format. A clinical evaluation and further testing is ongoing.</p><p></p>

scholarly journals Evaluation of accuracy, exclusivity, limit-of-detection and ease-of-use of LumiraDx™: An antigen-detecting point-of-care device for SARS-CoV-2

Infection ◽  
2021 ◽  
Author(s):  
Lisa J. Krüger ◽  
Julian A. F. Klein ◽  
Frank Tobian ◽  
Mary Gaeddert ◽  
Federica Lainati ◽  
...  
Keyword(s):  
Viral Load ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Scale Up ◽  
Cross Reactivity ◽  
Ease Of Use ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Clinical Sensitivity ◽  
Lateral Flow Assays

Abstract Purpose Rapid antigen-detecting tests (Ag-RDTs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transform pandemic control. Thus far, sensitivity (≤ 85%) of lateral-flow assays has limited scale-up. Conceivably, microfluidic immunofluorescence Ag-RDTs could increase sensitivity for SARS-CoV-2 detection. Methods This multi-centre diagnostic accuracy study investigated performance of the microfluidic immunofluorescence LumiraDx™ assay, enrolling symptomatic and asymptomatic participants with suspected SARS-CoV-2 infection. Participants collected a supervised nasal mid-turbinate (NMT) self-swab for Ag-RDT testing, in addition to a professionally collected nasopharyngeal (NP) swab for routine testing with reverse transcriptase polymerase chain reaction (RT-PCR). Results were compared to calculate sensitivity and specificity. Sub-analyses investigated the results by viral load, symptom presence and duration. An analytical study assessed exclusivity and limit-of-detection (LOD). In addition, we evaluated ease-of-use. Results The study was conducted between November 2nd 2020 and 4th of December 2020. 761 participants were enrolled, with 486 participants reporting symptoms on testing day. 120 out of 146 RT-PCR positive cases were detected positive by LumiraDx™, resulting in a sensitivity of 82.2% (95% CI 75.2–87.5%). Specificity was 99.3% (CI 98.3–99.7%). Sensitivity was increased in individuals with viral load ≥ 7 log10 SARS-CoV2 RNA copies/ml (93.8%; CI 86.2–97.3%). Testing against common respiratory commensals and pathogens showed no cross-reactivity and LOD was estimated to be 2–56 PFU/mL. The ease-of-use-assessment was favourable for lower throughput settings. Conclusion The LumiraDx™ assay showed excellent analytical sensitivity, exclusivity and clinical specificity with good clinical sensitivity using supervised NMT self-sampling. Trial registration number and registration date DRKS00021220 and 01.04.2020

scholarly journals A SARS-CoV-2 coronavirus nucleocapsid protein antigen-detecting lateral flow assay

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258819
Author(s):  
Benjamin D. Grant ◽  
Caitlin E. Anderson ◽  
Luis F. Alonzo ◽  
Spencer H. Garing ◽  
John R. Williford ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
World Health ◽  
Analytical Sensitivity ◽  
Rapid Diagnostics ◽  
Middle Income ◽  
Efficient Detection ◽  
Gamma Irradiated ◽  
Health Organization

Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format. While various manufacturers have produced commercially available SARS-Cov2 antigen LFAs, access to validated tests remains difficult or cost prohibitive in low-and middle-income countries. Herein, we present a visually read open-access LFA (OA-LFA) using commercially-available antibodies and materials for the detection of SARS-CoV-2. The LFA yielded a Limit of Detection (LOD) of 4 TCID50/swab of gamma irradiated SARS-CoV-2 virus, meeting the acceptable analytical sensitivity outlined by in World Health Organization target product profile. The open-source architecture presented in this manuscript provides a template for manufacturers around the globe to rapidly design a SARS-CoV2 antigen test.

scholarly journals A SARS-CoV-2 Coronavirus Nucleocapsid Protein Antigen-Detecting Lateral Flow Assay

2020 ◽  
Author(s):  
Ben D Grant ◽  
Caitlin E Anderson ◽  
Spencer H Garing ◽  
Luis F Alonzo ◽  
John R Williford ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Rapid Diagnostics ◽  
Rt Pcr ◽  
Efficient Detection ◽  
Lateral Flow Assays ◽  
Optical Reader ◽  
Polymerase Chain

<p></p><p>Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment and mitigation of COVID‑19. Currently, the primary diagnostic tool being utilized is reverse transcription polymerase chain reaction (RT-PCR). RT-PCR delivers results with good sensitivity and excellent specificity, but is expensive, prone to access challenges and is often slowed by transport to centralized testing laboratories. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed, with lateral flow assays (LFAs) being the most common inexpensive antigen test. To date, few antigen-detecting LFAs for COVID-19 have been commercialized. Herein, we present an open source LFA using commercially available antibodies and materials for the detection of SARS-CoV-2. Using an optical reader with comparable sensitivity to a visual read, the LFA yielded a Limit of Detection (LOD) of 23 TCID<sub>50</sub>/mL (95% CI of 9.1 to 37 TCID<sub>50</sub>/mL), equivalent to 1.4x10<sup>5</sup> copies/mL (95% CI of 5.5x10<sup>4</sup> to 2.3x10<sup>5</sup> copies/mL) irradiated virus in pooled nasal matrix. This LOD meets the criteria suggested by WHO for diagnosis of acute SARS-CoV-2 infection in a point of care format. A clinical evaluation and further testing is ongoing.</p><p></p>

Gold-Aptamer-Nanoconstructs Engineered to Detect Conserved Enteroviral Nucleic Acid Sequences

2019 ◽  
Author(s):  
Veeren Chauhan ◽  
Mohamed M Elsutohy ◽  
C Patrick McClure ◽  
Will Irving ◽  
Neil Roddis ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
In Silico ◽  
Point Of Care ◽  
Lateral Flow ◽  
Nucleic Acid Sequence ◽  
In Silico Screening ◽  
Lateral Flow Assays ◽  
Life Threatening ◽  
Software And Hardware ◽  
Nucleic Acid Sequences

<p>Enteroviruses are a ubiquitous mammalian pathogen that can produce mild to life-threatening disease. Bearing this in mind, we have developed a rapid, accurate and economical point-of-care biosensor that can detect a nucleic acid sequences conserved amongst 96% of all known enteroviruses. The biosensor harnesses the physicochemical properties of gold nanoparticles and aptamers to provide colourimetric, spectroscopic and lateral flow-based identification of an exclusive enteroviral RNA sequence (23 bases), which was identified through in silico screening. Aptamers were designed to demonstrate specific complementarity towards the target enteroviral RNA to produce aggregated gold-aptamer nanoconstructs. Conserved target enteroviral nucleic acid sequence (≥ 1x10<sup>-7</sup> M, ≥1.4×10<sup>-14</sup> g/mL), initiates gold-aptamer-nanoconstructs disaggregation and a signal transduction mechanism, producing a colourimetric and spectroscopic blueshift (544 nm (purple) > 524 nm (red)). Furthermore, lateral-flow-assays that utilise gold-aptamer-nanoconstructs were unaffected by contaminating human genomic DNA, demonstrated rapid detection of conserved target enteroviral nucleic acid sequence (< 60 s) and could be interpreted with a bespoke software and hardware electronic interface. We anticipate our methodology will translate in-silico screening of nucleic acid databases to a tangible enteroviral desktop detector, which could be readily translated to related organisms. This will pave-the-way forward in the clinical evaluation of disease and complement existing strategies at overcoming antimicrobial resistance.</p>

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