scholarly journals Instrumentation-Free Semiquantitative Immunoanalysis Using a Specially Patterned Lateral Flow Assay Device

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 87
Author(s):  
Kyung Won Lee ◽  
Ye Chan Yu ◽  
Hyeong Jin Chun ◽  
Yo Han Jang ◽  
Yong Duk Han ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Optical Probe ◽  
Lateral Flow ◽  
Analyte Concentration ◽  
Detection Range ◽  
Optical Instruments ◽  
Naked Eye ◽  
Resource Limited ◽  
Test Zone ◽  
Artificial Urine

In traditional colorimetric lateral flow immunoassay (LFI) using gold nanoparticles (AuNPs) as a probe, additional optical transducers are required to quantify the signal intensity of the test line because it presents as a single red-colored line. In order to eliminate external equipment, the LFI signal should be quantifiable by the naked eye without the involvement of optical instruments. Given this objective, the single line test zone of conventional LFI was converted to several spots that formed herringbone patterns. When the sandwich immunoassay was performed on a newly developed semi-quantitative (SQ)-LFI system using AuNPs as an optical probe, the spots were colorized and the number of colored spots increased proportionally with the analyte concentration. By counting the number of colored spots, the analyte concentration can be easily estimated with the naked eye. To demonstrate the applicability of the SQ-LFI system in practical immunoanalysis, microalbumin, which is a diagnostic marker for renal failure, was analyzed using microalbumin-spiked artificial urine samples. Using the SQ-LFI system, the calibration results for artificial urine-based microalbumin were studied, ranging from 0 to 500 μg/mL, covering the required clinical detection range, and the limit of detection (LOD) value was calculated to be 15.5 μg/mL. Thus, the SQ-LFI system provides an avenue for the realization of an efficient quantification diagnostic device in resource-limited conditions.

scholarly journals Monoclonal Antibodies Application in Lateral Flow Immunochromatographic Assays for Drugs of Abuse Detection

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1058
Author(s):  
Zidane Qriouet ◽  
Yahia Cherrah ◽  
Hassan Sefrioui ◽  
Zineb Qmichou
Keyword(s):  
High Performance ◽  
Drugs Of Abuse ◽  
Limit Of Detection ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Gas Chromatography Mass Spectrometry ◽  
Resource Limited ◽  
Short Period ◽  
Reaction Gas Chromatography ◽  
Lateral Flow Assays

Lateral flow assays (lateral flow immunoassays and nucleic acid lateral flow assays) have experienced a great boom in a wide variety of early diagnostic and screening applications. As opposed to conventional examinations (High Performance Liquid Chromatography, Polymerase Chain Reaction, Gas chromatography-Mass Spectrometry, etc.), they obtain the results of a sample’s analysis within a short period. In resource-limited areas, these tests must be simple, reliable, and inexpensive. In this review, we outline the production process of antibodies against drugs of abuse (such as heroin, amphetamine, benzodiazepines, cannabis, etc.), used in lateral flow immunoassays as revelation or detection molecules, with a focus on the components, the principles, the formats, and the mechanisms of reaction of these assays. Further, we report the monoclonal antibody advantages over the polyclonal ones used against drugs of abuse. The perspective on aptamer use for lateral flow assay development was also discussed as a possible alternative to antibodies in view of improving the limit of detection, sensitivity, and specificity of lateral flow assays.

Development of a monoclonal antibody for the detection of xylazine in milk and its use in an immunochromatographic strip

2021 ◽  
Author(s):  
Mengjia Chao ◽  
Liqiang Liu ◽  
Aihong Wu ◽  
Shanshan Song ◽  
Xinxin Xu ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Gold Nanoparticle ◽  
Limit Of Detection ◽  
Lateral Flow ◽  
Immunochromatographic Strip ◽  
Naked Eye ◽  
Milk Samples ◽  
Flow Test ◽  
Lateral Flow Test

A gold nanoparticle-based lateral-flow test (GNT) strip was developed to detect xylazine (XYL) in milk. And the limit of detection (LOD) and cut-off value of the GNT assay were evaluated to be 20 and 200 ng mL−1 in milk samples by the naked eye.

A Rapid and Sensitive Aptasensor for Cyromazine Detection in Raw Milk Based on a Nanogold Probe and G-Quadruplex Formation

2019 ◽  
Vol 72 (7) ◽  
pp. 555
Author(s):  
Xu Dang ◽  
Wenchao Gu ◽  
Xiyin Zheng ◽  
Xuelian Fei ◽  
Fuxiang Tian ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Raw Milk ◽  
Cationic Polymer ◽  
Remarkable Change ◽  
Detection Range ◽  
Naked Eye ◽  
Diallyldimethylammonium Chloride ◽  
G Quadruplex ◽  
Quadruplex Formation

Herein, a rapid, facile, and colourimetric sensor for the detection of cyromazine in raw milk is reported using an aptamer based on gold nanoparticles (AuNPs). A sequence-specific aptamer for cyromazine called Tcyr1 is designed to absorb on the surface of AuNPs and electrostatically interacts with poly(diallyldimethylammonium chloride) (PDDA), which prevents AuNPs from aggregating. It can also self-assemble to form a G-quadruplex-CYR complex with cyromazine. Because of its specificity and stability, the introduction of cyromazine in raw milk would influence the protection thus the following cationic polymer could aggregate AuNPs and cause a remarkable change in colour. According to this, the presence of cyromazine can be determined by the naked eye and means of absorbance. This sensor is selective for the detection of cyromazine in raw milk and has a limit of detection of 200 ppb by the naked eye and of 5.8 ppb by spectrophotometer, and has a detection range from 0.1 to 1 ppm.

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.

scholarly journals A Compact Detection Platform Based on Gradient Guided-Mode Resonance for Colorimetric and Fluorescence Liquid Assay Detection

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2797
Author(s):  
Jing-Jhong Gao ◽  
Ching-Wei Chiu ◽  
Kuo-Hsing Wen ◽  
Cheng-Sheng Huang
Keyword(s):  
Limit Of Detection ◽  
Detection System ◽  
Fluorescence Emission ◽  
Assay Sensitivity ◽  
Detection Range ◽  
Current Form ◽  
Guided Mode ◽  
Spectral Detection ◽  
Guided Mode Resonance ◽  
Colorimetric Assays

This paper presents a compact spectral detection system for common fluorescent and colorimetric assays. This system includes a gradient grating period guided-mode resonance (GGP-GMR) filter and charge-coupled device. In its current form, the GGP-GMR filter, which has a size of less than 2.5 mm, can achieve a spectral detection range of 500–700 nm. Through the direct measurement of the fluorescence emission, the proposed system was demonstrated to detect both the peak wavelength and its corresponding intensity. One fluorescent assay (albumin) and two colorimetric assays (albumin and creatinine) were performed to demonstrate the practical application of the proposed system for quantifying common liquid assays. The results of our system exhibited suitable agreement with those of a commercial spectrometer in terms of the assay sensitivity and limit of detection (LOD). With the proposed system, the fluorescent albumin, colorimetric albumin, and colorimetric creatinine assays achieved LODs of 40.99 and 398 and 25.49 mg/L, respectively. For a wide selection of biomolecules in point-of-care applications, the spectral detection range achieved by the GGP-GMR filter can be further extended and the simple and compact optical path configuration can be integrated with a lab-on-a-chip system.

scholarly journals Recent Advancements in Enzyme-Based Lateral Flow Immunoassays

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3358
Author(s):  
Donato Calabria ◽  
Maria Maddalena Calabretta ◽  
Martina Zangheri ◽  
Elisa Marchegiani ◽  
Ilaria Trozzi ◽  
...  
Keyword(s):  
Lateral Flow ◽  
Qualitative Information ◽  
Eye Color ◽  
Commercial Success ◽  
Color Changes ◽  
Naked Eye ◽  
Future Developments ◽  
Highly Sensitive ◽  
Critical Overview ◽  
Detection Technologies

Paper-based lateral-flow immunoassays (LFIAs) have achieved considerable commercial success and their impact in diagnostics is continuously growing. LFIA results are often obtained by visualizing by the naked eye color changes in given areas, providing a qualitative information about the presence/absence of the target analyte in the sample. However, this platform has the potential to provide ultrasensitive quantitative analysis for several applications. Indeed, LFIA is based on well-established immunological techniques, which have known in the last year great advances due to the combination of highly sensitive tracers, innovative signal amplification strategies and last-generation instrumental detectors. All these available progresses can be applied also to the LFIA platform by adapting them to a portable and miniaturized format. This possibility opens countless strategies for definitively turning the LFIA technique into an ultrasensitive quantitative method. Among the different proposals for achieving this goal, the use of enzyme-based immunoassay is very well known and widespread for routine analysis and it can represent a valid approach for improving LFIA performances. Several examples have been recently reported in literature exploiting enzymes properties and features for obtaining significative advances in this field. In this review, we aim to provide a critical overview of the recent progresses in highly sensitive LFIA detection technologies, involving the exploitation of enzyme-based amplification strategies. The features and applications of the technologies, along with future developments and challenges, are also discussed.

scholarly journals Ratiometric Fluorescent Biosensors for Glucose and Lactate Using an Oxygen-Sensing Membrane

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 208
Author(s):  
Hong Dinh Duong ◽  
Jong Il Rhee
Keyword(s):  
Limit Of Detection ◽  
Oxygen Sensing ◽  
High Sensitivity ◽  
Glucose Sensing ◽  
Oxidation Reactions ◽  
Lactate Oxidase ◽  
Lactate Oxidation ◽  
Detection Range ◽  
Quenching Effect ◽  
Sensing Membrane

In this study, ratiometric fluorescent glucose and lactate biosensors were developed using a ratiometric fluorescent oxygen-sensing membrane immobilized with glucose oxidase (GOD) or lactate oxidase (LOX). Herein, the ratiometric fluorescent oxygen-sensing membrane was fabricated with the ratio of two emission wavelengths of platinum meso-tetra (pentafluorophenyl) porphyrin (PtP) doped in polystyrene particles and coumarin 6 (C6) captured into silica particles. The operation mechanism of the sensing membranes was based on (i) the fluorescence quenching effect of the PtP dye by oxygen molecules, and (ii) the consumption of oxygen levels in the glucose or lactate oxidation reactions under the catalysis of GOD or LOX. The ratiometric fluorescent glucose-sensing membrane showed high sensitivity to glucose in the range of 0.1–2 mM, with a limit of detection (LOD) of 0.031 mM, whereas the ratiometric fluorescent lactate-sensing membrane showed the linear detection range of 0.1–0.8 mM, with an LOD of 0.06 mM. These sensing membranes also showed good selectivity, fast reversibility, and stability over long-term use. They were applied to detect glucose and lactate in artificial human serum, and they provided reliable measurement results.

scholarly journals Recombinase-Aided Amplification Coupled with Lateral Flow Dipstick for Efficient and Accurate Detection of Porcine Parvovirus

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 762
Author(s):  
Yihong He ◽  
Wenxian Chen ◽  
Jindai Fan ◽  
Shuangqi Fan ◽  
Hongxing Ding ◽  
...  
Keyword(s):  
Detection Method ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Porcine Parvovirus ◽  
Swine Industry ◽  
Resource Limited ◽  
Efficient Detection ◽  
Lateral Flow Dipstick ◽  
Polymerase Chain ◽  
Embryonic Death

Porcine parvovirus (PPV) infection is the primary cause of SMEDI (stillbirth; mummification; embryonic death; infertility) syndrome, which is a global burden for the swine industry. Thus, it is crucial to establish a rapid and efficient detection method against PPV infection. In the present work, we developed a recombinase-aided amplification (RAA) assay, coupled with a lateral flow dipstick (LFD), to achieve an amplification of PPV DNA at 37 °C within 15 min. The detection limits of PPV RAA-LFD assay were 102 copies/μL recombinant plasmid pMD19-T-VP1, 6.38 × 10−7 ng/μL PPV DNA, and 10−1 TCID50/mL virus, respectively. This method was highly specific for PPV detection with no cross-reactivity for other swine pathogens. In contrast to polymerase chain reaction (PCR), the PPV RAA-LFD assay is more sensitive and cost-saving. Hence, the established PPV RAA-LFD assay provided an alternative for PPV detection, especially in resource-limited regions.

Chromogenic ‘naked eye’ and fluorogenic ‘turn on’ sensor for mercury metal ion using thiophene-based Schiff base

RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 65731-65738 ◽  
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh
Keyword(s):  
Schiff Base ◽  
Binding Affinity ◽  
Metal Ion ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Naked Eye ◽  
Turn On

2-((3-Methylthiophen-2-yl)methyleneamino)benzenethiol (Probe 1) is selective for Hg2+. The binding affinity of Hg2+ with Probe 1 was confirmed by DFT and electrochemical behaviour. The limit of detection was 20 μM with 2 : 1 stoichiometry of 1 + Hg2+ complex.

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