scholarly journals Sensitive Colorimetric Detection of Interleukin-6 via Lateral Flow Assay Incorporated Silver Amplification Method

2021 ◽  
Vol 9 ◽  
Author(s):  
Mohammad Rahbar ◽  
Yuling Wu ◽  
J. Anand Subramony ◽  
Guozhen Liu
Keyword(s):  
Interleukin 6 ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Quantitative Detection ◽  
Amplification Method ◽  
Silver Amplification

Interleukin-6 (IL-6) is a pro/anti-inflammatory cytokine, the quantitative detection of which has been extensively considered for diagnosis of inflammatory associated diseases. However, there has not yet been a reliable, low-cost, and user-friendly platform developed for point-of-care (POC) detection of IL-6, which will eliminate the conventional costly, time-consuming, and complex assays. In this work, we developed a lateral flow assay for colorimetric detection of IL-6, using anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs) as the detection probes. Silver amplification technique was incorporated with the newly developed assay in order to enhance the obtained colorimetric signals, allowing sensitive detection of IL-6 in human serum in the desired physiological ranges (i.e., 5–1000 pg/mL). A limit of detection of 5 pg/mL could be achieved for IL-6 detection in serum with the amplification step which was not achievable in the standard assay. The corresponding specificity and reproducibility tests were all preformed to confirm the reliability of this assay for quantitative measurement of IL-6 in a POC manner.

A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

2020 ◽  
Author(s):  
Carla Eiras
Keyword(s):  
Interleukin 6 ◽  
Limit Of Detection ◽  
Inflammatory Diseases ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Aggregation Assay ◽  
Before And After ◽  
Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM).The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

2020 ◽  
Author(s):  
Carla Eiras
Keyword(s):  
Interleukin 6 ◽  
Limit Of Detection ◽  
Inflammatory Diseases ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Aggregation Assay ◽  
Before And After ◽  
Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated at a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM). The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

Sample Preincubation Strategy for Sensitive and Quantitative Detection of Clenbuterol in Swine Urine Using a Fluorescent Microsphere–Based Immunochromatographic Assay

2014 ◽  
Vol 77 (11) ◽  
pp. 1998-2003 ◽  
Author(s):  
SHENG L. DENG ◽  
SHAN SHAN ◽  
CHAO L. XU ◽  
DAO F. LIU ◽  
YONG H. XIONG ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Rapid Screening ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fluorescent Microsphere ◽  
Swine Urine ◽  
Relative Standard

We describe an ultrasensitive and quantitative immunochromatographic assay to determine the amount of clenbuterol (CLB) in swine urine. In this study, fluorescein isothiocyanate polystyrene fluorescent microspheres were used as probes. A sample preincubation strategy was introduced to this immunochromatographic assay. Results showed that the strategy evidently improved the sensitivity and accuracy of lateral flow assay. The method was completed in 20 min, and a half-maximal inhibitory concentration of 0.13 μg liter−1 was obtained. The limit of detection of the proposed method to determine CLB in swine urine was 0.01 μg liter−1, which was lower than the limit of detection of immunochromatographic assays without preincubation. Intra-and interday recoveries of spiked swine urine ranged from 85.0 to 107.5%. The relative standard deviation values of the preincubated test strip ranged from 2.7 to 12.5%. Analysis of the CLB in swine urine samples showed that the result obtained from the lateral flow assay is consistent with that obtained from a commercial enzyme-linked immunosorbent assay kit. Our results suggest that the developed fluorescent microsphere–based immunochromatographic assay may be useful as a rapid screening method to detect CLB quantitatively.

scholarly journals Colorimetric Determination of Nitrate after Reduction to Nitrite in a Paper-Based Dip Strip

2021 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Amer Charbaji ◽  
Hojat Heidari-Bafroui ◽  
Nasim Rahmani ◽  
Constantine Anagnostopoulos ◽  
Mohammad Faghri
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Water Quality Monitoring ◽  
Colorimetric Determination ◽  
Limit Of Quantification ◽  
Point Of Care Diagnostics ◽  
Reduction Efficiency ◽  
Nitrate And Nitrite

Paper-based microfluidic technology is a relatively new field of research that provides low-cost platforms and sensors for point-of-care diagnostics. While the majority of research in this field has been for biomedical applications, more and more paper-based devices and platforms are being designed and developed for environmental applications, such as water quality monitoring and assessment. One such application is the detection of nitrate in water samples. Colorimetric detection of nitrate by paper-based devices using the Griess assay requires the reduction of nitrate to nitrite before undergoing the reaction. In this paper, we measured the performance of a paper-based dip strip for detecting nitrate and nitrite by calculating its limit of detection and limit of quantification. We also calculated the reduction efficiency of vanadium (III) chloride in the dip strip for detecting nitrate. Our results show that the reduction time of nitrate via vanadium (III) chloride is much longer than that when using zinc microparticles. Our results also show that the performance of the dip strip using vanadium (III) chloride for nitrate detection is not as good as more intricate paper-based devices that have a separate reaction zone with zinc microparticles. The limits of detection and quantification calculated were 3.352 and 7.437 ppm, and the nitrate reduction efficiency varied over the range of nitrate concentrations tested.

Rapid Detection of Shellfish Major Allergen Tropomyosin Using Superparamagnetic Nanoparticle-Based Lateral Flow Immunoassay

2011 ◽  
Vol 311-313 ◽  
pp. 436-445 ◽  
Author(s):  
Liang Shi ◽  
Xi Chang Wang ◽  
Yuan Liu ◽  
Ying Lu
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
High Specificity ◽  
Major Allergen ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Quantitative Detection ◽  
Point Of Care Test ◽  
Western Blot Method ◽  
Food Species

In this study, a competitive assay format using superparamagnetic nanoparticle-based lateral flow immunoassay (LFIA) was developed for rapid, quantitative detection of shellfish major allergen tropomyosin (Tm). Sartorius CN140 nitrocellulose membrane and 0.05mg/mL Tm immobilized in the test line (T line) were optimized in order to improve the performance of the LFIA system. Calibration curves for Tm under PBS-T diluents and carp muscle extraction diluents were established. Limit of detection (LOD) for Tm calibrated by carp muscle matrix was 12.4ng/mL with a work range of 0.01 to 20μg/mL. According to magnetic signals change with the time of sample flowing on the strip, the qualitative time of the LFIA was about 10min, while the quantitative time of the LFIA was about 25min. 30 food species were detected separately by the LFIA and Western blot method to evaluate the specificity of the LFIA. Overall relative agreement of the two methods was 96.7% (29/30). Moreover, intra- and inter-assay precisions of the LFIA for Tm detection were <10.20% and <12.34%, respectively. The average recovery range in different food matrices was 80.3~111.8%, within a reasonable range. Our data confirmed that the superparamagnetic nanoparticle-based LFIA method developed in this study is rapid, simple, high specificity and capable of quantitative test. Consequently, the LFIA has the potential application in the field of point-of-care test of shellfish major allergen Tm.

Lateral flow assay with pressure meter readout for rapid point-of-care detection of disease-associated protein

Lab on a Chip ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 965-970 ◽  
Author(s):  
Bingqian Lin ◽  
Zhichao Guan ◽  
Yanling Song ◽  
Eunyeong Song ◽  
Zifei Lu ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Lateral Flow Assays ◽  
Pressure Meter ◽  
User Friendly ◽  
Point Of Care Detection

Paper-based assays such as lateral flow assays are good candidates for portable diagnostics owing to their user-friendly format and low cost.

scholarly journals Rapid and Sensitive Detection of miRNA Based on AC Electrokinetic Capacitive Sensing for Point-of-Care Applications

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3985
Author(s):  
Nan Wan ◽  
Yu Jiang ◽  
Jiamei Huang ◽  
Rania Oueslati ◽  
Shigetoshi Eda ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Clinical Diagnostics ◽  
Detection Methods ◽  
Capacitive Sensing ◽  
Application Potential ◽  
Mirna Detection ◽  
Mirna 25 ◽  
Low Sensitivity

A sensitive and efficient method for microRNAs (miRNAs) detection is strongly desired by clinicians and, in recent years, the search for such a method has drawn much attention. There has been significant interest in using miRNA as biomarkers for multiple diseases and conditions in clinical diagnostics. Presently, most miRNA detection methods suffer from drawbacks, e.g., low sensitivity, long assay time, expensive equipment, trained personnel, or unsuitability for point-of-care. New methodologies are needed to overcome these limitations to allow rapid, sensitive, low-cost, easy-to-use, and portable methods for miRNA detection at the point of care. In this work, to overcome these shortcomings, we integrated capacitive sensing and alternating current electrokinetic effects to detect specific miRNA-16b molecules, as a model, with the limit of detection reaching 1.0 femto molar (fM) levels. The specificity of the sensor was verified by testing miRNA-25, which has the same length as miRNA-16b. The sensor we developed demonstrated significant improvements in sensitivity, response time and cost over other miRNA detection methods, and has application potential at point-of-care.

scholarly journals PERFORMANCE CHARACTERISTICS OF A FRET-BASED IMMUNOASSAY FOR QUANTITATION OF INFLIXIMAB ON A POINT-OF-CARE INSTRUMENT SYSTEM

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S57-S57
Author(s):  
Edgar Ong ◽  
Ruo Huang ◽  
Richard Kirkland ◽  
Michael Hale ◽  
Larry Mimms
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Hook Effect ◽  
Limit Of Quantitation ◽  
Assay Precision

Abstract Introduction A fast (&lt;5 min), time-resolved fluorescence resonance energy transfer (FRET)-based immunoassay was developed for the quantitative detection of infliximab (IFX) and biosimilars for use in therapeutic drug monitoring using only 20 µL of fingerstick whole blood or serum at the point-of-care. The Procise IFX assay and ProciseDx analyzer are CE-marked. Studies were performed to characterize analytical performance of the Procise IFX assay on the ProciseDx analyzer. Methods Analytical testing was performed by spiking known amounts of IFX into negative serum and whole blood specimens. Analytical sensitivity was determined using limiting concentrations of IFX. Linearity was determined by testing IFX across the assay range. Hook effect was assessed at IFX concentrations beyond levels expected to be found within a patient. Testing of assay precision, cross-reactivity and potential interfering substances, and biosimilars was performed. The Procise IFX assay was also compared head-to-head with another CE-marked assay: LISA-TRACKER infliximab ELISA test (Theradiag, France). The accuracy of the Procise IFX assay is established through calibrators and controls traceable to the WHO 1st International Standard for Infliximab (NIBSC code: 16/170). Results The Procise IFX assay shows a Limit of Blank, Limit of Detection, and Lower Limit of Quantitation (LLoQ) of 0.1, 0.2, and 1.1 µg/mL in serum and 0.6, 1.1, and 1.7 µg/mL in whole blood, respectively. The linear assay range was determined to be 1.7 to 77.2 µg/mL in serum and whole blood. No hook effect was observed at an IFX concentration of 200 µg/mL as the value reported as “&gt;ULoQ”. Assay precision testing across 20 days with multiple runs and reagent lots showed an intra-assay coefficient of variation (CV) of 2.7%, an inter-assay CV of &lt;2%, and a total CV of 3.4%. The presence of potentially interfering/cross-reacting substances showed minimal impact on assay specificity with %bias within ±8% of control. Testing of biosimilars (infliximab-dyyb and infliximab-abda) showed good recovery. A good correlation to the Theradiag infliximab ELISA was obtained for both serum (slope=1.01; r=0.99) and whole blood (slope=1.01; r=0.98) samples (Figure 1). Conclusion Results indicate that the Procise IFX assay is sensitive, specific, and precise yielding results within 5 minutes from both whole blood and serum without the operator needing to specify sample type. Additionally, it shows very good correlation to a comparator assay that takes several hours and sample manipulation to yield results. This makes the Procise IFX assay ideal for obtaining fast and accurate IFX quantitation, thus allowing for immediate drug level dosing decisions to be made by the physician during patient treatment.

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 Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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