Enhancement of the detection limit for lateral flow immunoassays: Evaluation and comparison of bioconjugates

2012 ◽  
Vol 375 (1-2) ◽  
pp. 264-270 ◽  
Author(s):  
Elisângela M. Linares ◽  
Lauro T. Kubota ◽  
Jens Michaelis ◽  
Stefan Thalhammer
Keyword(s):  
Detection Limit ◽  
Lateral Flow

An improved detection limit and working range of lateral flow assays based on a mathematical model

The Analyst ◽  
2018 ◽  
Vol 143 (12) ◽  
pp. 2775-2783 ◽  
Author(s):  
Zhi Liu ◽  
Zhiguo Qu ◽  
Ruihua Tang ◽  
Xiaocong He ◽  
Hui Yang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Detection Limit ◽  
Lateral Flow ◽  
Lateral Flow Assays

The detection limit and working range of lateral flow assays are investigated experimentally and numerically.

scholarly journals Multiplex recombinase polymerase amplification (RPA) assay developed using unique genomic regions and coupled with a lateral flow device for rapid on-site detection of genus Clavibacter and C. nebraskensis

2020 ◽  
Author(s):  
Adriana Larrea-Sarmiento ◽  
James P. Stack ◽  
Anne M. Alvarez ◽  
Mohammad Arif
Keyword(s):  
Detection Limit ◽  
Abc Transporter ◽  
Bacterial Species ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Specific Primer ◽  
Lateral Flow Device ◽  
Flow Device ◽  
Genomic Regions ◽  
Probe Set

ABSTRACTClavibacter is an agriculturally important bacterial genus comprising nine host-specific species/subspecies including C. nebraskensis (Cn), which causes Goss’s wilt and blight of maize. A robust, simple, and field-deployable method is required to specifically detect Cn in infected plants and distinguish it from other Clavibacter species for quarantine purposes and timely disease management. A multiplex Recombinase Polymerase Amplification (RPA) coupled with a Lateral Flow Device (LFD) was developed for sensitive and rapid detection of Clavibacter and Cn directly from infected host. Unique and conserved genomic regions, the ABC transporter ATP-binding protein CDS/ABC-transporter permease and the MFS transporter gene, were used to design primers/probes for specific detection of genus Clavibacter and Cn, respectively. The assay was evaluated using 52 strains, representing all nine species/subspecies of Clavibacter, other closely related bacterial species, and naturally- and artificially-infected plant samples; no false positives or negatives were detected. The RPA reactions were also incubated in a closed hand at body temperature; results were again specific. The assay does not require DNA isolation and can be directly performed using host sap. The detection limit of 10 pg and 100 fg was determined for Clavibacter- and Cn-specific primers/probes, respectively. The detection limit for Cn-specific primer/probe set was decreased to 1,000 fg when 1 µL of host sap was added into the RPA reaction containing 10-fold serially diluted genomic DNA; though no effect was observed on Clavibacter-specific primer/probe set. The assay is accurate and has applications at point-of-need diagnostics. This is the first multiplex RPA for any plant pathogen.IMPORTANCEClavibacter species are prevalent worldwide as have the potential to result in systemic infection. In the past, detection attempts have relied on both molecular- and immunological-based assays; however, current detection methods are time consuming and laborious. Field-deployable tests are desirable to identify potential samples infected with Clavibacter species. This study demonstrates that the field-deployable isothermal multi-target recombinase polymerase amplification can be performed for the simultaneous detection of the genus Clavibacter in general (all species), and C. nebraskensis, in particular, without specialized equipment. Additionally, the multiplex RPA coupled with a LFD may confer the benefits of faster detection and discrimination of Clavibacter species that affect critical regions susceptible to infection. This user-friendly format offers a flexible assay to complement both nucleic acid amplification and novel diagnosis methods without the need for DNA purification; this assay may serve as a point-of-reference for developing multiplex RPA assay for other plant pathogens.

scholarly journals Application of Loop-Mediated Isothermal Amplification combined with colorimetric and lateral flow dipstick visualization as the potential point-of-care testing for diphtheria

2019 ◽  
Author(s):  
Aleksandra Anna Zasada ◽  
Aldona Wiatrzyk ◽  
Urszula Czajka ◽  
Klaudia Brodzik ◽  
Kamila Formińska ◽  
...  
Keyword(s):  
Detection Limit ◽  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Lamp Assay ◽  
Corynebacterium Diphtheriae ◽  
Lateral Flow ◽  
Isothermal Amplification ◽  
Suspected Case ◽  
Point Of Care Testing ◽  
Loop Mediated Isothermal Amplification

Abstract Background Diphtheria outbreaks occurred in endemic areas and imported and indigenous cases are reported in UE/EEA. Because of the high infectiveness and severity of the disease, early and accurate diagnosis of each suspected case is essential for the treatment and management of the case and close contacts. The aim of the study was to establish simple and rapid testing methods based on Loop-Mediated Isothermal Amplification (LAMP) assay for the detection of Corynebacterium diphtheriae and differentiation between toxigenic and non-toxigenic strains.Methods Corynebacterium diphtheriae and Corynebacterium ulcerans isolates from the National Institute of Public Health-National Institute of Hygiene collection were used for the development of LAMP assay for the diagnosis of diphtheria and nontoxigenic C. diphtheriae infections. Various colorimetric methods for visualization of results were investigated. Sensitivity and specificity of the assay were examined using a collection of DNA samples from various gram-positive and gram-negative bacteria.Results The LAMP assay for tox and dtxR genes was developed. The sensitivity and specificity of the assay were calculated as 100%. The detection limit was estimated as 1.42 pg/µl concentration of DNA template when the reaction was conducted for 60 min. However, the detection limit was lowered 10 times for every 10 minutes of reduction in the time of incubation during the reaction. Positive results were successfully detected colorimetrically using hydroxynaphthol blue, calcein, QuantiFluor, and lateral flow Milenia HybriDetect dipsticks.Conclusion The assay developed in the study might be applied for point-of-care testing of diphtheria and other C. diphtheriae infections. It is highly sensitive, specific, inexpensive, easy to use, and suitable for low-resource settings.

scholarly journals Developing Gold Nanoparticles-Conjugated Aflatoxin B1 Antifungal Strips

2019 ◽  
Vol 20 (24) ◽  
pp. 6260 ◽  
Author(s):  
Tobiloba Sojinrin ◽  
Kangze Liu ◽  
Kan Wang ◽  
Daxiang Cui ◽  
Hugh J. Byrne ◽  
...  
Keyword(s):  
Detection Limit ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Point Of Care ◽  
Colour Change ◽  
Food Samples ◽  
Lateral Flow ◽  
Resonance Spectroscopy ◽  
Immunochromatographic Strip ◽  
Specificity And Sensitivity

Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests, based on their simplicity, specificity, and sensitivity. In this study, a rapid and sensitive gold nanoparticle (AuNP) immunochromatographic strip is produced for detecting aflatoxin B1 (AFB1) in suspicious fungi-contaminated food samples. The 10 nm AuNPs were encompassed by bovine serum albumin (BSA) and AFB1 antibody. Thin-layer chromatography, gel electrophoresis and nuclear magnetic resonance spectroscopy were employed for analysing the chemical complexes. Various concentrations of AFB1 antigen (0–16 ng/mL) were tested with AFB1 antibody–BSA–AuNPs (conjugated AuNPs) and then analysed by scanning electron microscopy, ultraviolet–visible spectroscopy, and Zetasizer. The results showed that the AFB1 antibody was coupled to BSA by the N-hydroxysuccinimide ester method. The AuNPs application has the potential to contribute to AFB1 detection by monitoring a visible colour change from red to purple-blue, with a detection limit of 2 ng/mL in a 96-well plate. The lateral flow immunochromatographic strip tests are rapid, taking less than 10 min., and they have a detection capacity of 10 ng/g. The smartphone analysis of strips provided the results in 3 s, with a detection limit of 0.3 ng/g for AFB1 when the concentration was below 10 ng/g. Excellent agreement was found with AFB1 determination by high-performance liquid chromatography in the determination of AFB1 among 20 samples of peanuts, corn, rice, and bread.

scholarly journals Two Orders of Magnitude Improvement in Detection Limit of Lateral Flow Assays Using Isotachophoresis

2015 ◽  
Vol 87 (2) ◽  
pp. 1009-1017 ◽  
Author(s):  
Babak Y. Moghadam ◽  
Kelly T. Connelly ◽  
Jonathan D. Posner
Keyword(s):  
Detection Limit ◽  
Lateral Flow ◽  
Lateral Flow Assays ◽  
Magnitude Improvement

scholarly journals Modification of a nitrocellulose membrane with nanofibers for sensitivity enhancement in lateral flow test strips

RSC Advances ◽  
2021 ◽  
Vol 11 (43) ◽  
pp. 26493-26501
Author(s):  
Xue Wang ◽  
Chao-Hua Xue ◽  
Dong Yang ◽  
Shun-Tian Jia ◽  
Ya-Ru Ding ◽  
...  
Keyword(s):  
Detection Limit ◽  
Sensitivity Enhancement ◽  
Lateral Flow ◽  
Fibrous Membrane ◽  
Nitrocellulose Membrane ◽  
Test Strips ◽  
Flow Test ◽  
New Type ◽  
Lateral Flow Test

We constructed a new type of ICT strip by replacing the conventional nitrocellulose membrane with an electrospin-coated nitrocellulose (ENC) fibrous membrane, and the ICT strip could obtain an HCG detection limit of 0.22 mIU mL−1, and an LH detection limit of 0.36 mIU mL−1.

scholarly journals Gold Nanobeads with Enhanced Absorbance for Improved Sensitivity in Competitive Lateral Flow Immunoassays

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1488
Author(s):  
Xirui Chen ◽  
Xintao Miao ◽  
Tongtong Ma ◽  
Yuankui Leng ◽  
Liangwen Hao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Inhibitory Concentration ◽  
Fumonisin B1 ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Promising Strategy ◽  
Qualitative Detection ◽  
Better Than

Background: Colloidal gold based lateral flow immunoassay (LFIA) commonly suffers from relatively low detection sensitivity due to the insufficient brightness of conventional gold nanoparticles (AuNPs) with the size of 20–40 nm. Methods: Herein, three kinds of gold nanobeads (GNBs) with the size of 94 nm, 129 nm, and 237 nm, were synthesized by encapsulating numerous hydrophobic AuNPs (10 nm) into polymer matrix. The synthesized GNBs exhibited the enhanced colorimetric signal intensity compared with 20–40 nm AuNPs. The effects of the size of GNBs on the sensitivity of LFIA with competitive format were assessed. Results: The results showed that the LFIA using 129 nm GNBs as amplified signal probes exhibits the best sensitivity for fumonisin B1 (FB1) detection with a cut-off limit (for visual qualitative detection) at 125 ng/mL, a half maximal inhibitory concentration at 11.27 ng/mL, and a detection limit at 1.76 ng/mL for detection of real corn samples, which are 8-, 3.82-, and 2.89-fold better than those of conventional AuNP40-based LFIA, respectively. The developed GNB-LFIA exhibited negligible cross-reactions with other common mycotoxins. In addition, the accuracy, precision, reliability, and practicability were demonstrated by determining real corn samples. Conclusions: All in all, the proposed study provides a promising strategy to enhance the sensitivity of competitive LFIA via using the GNBs as amplified signal probes.

Electrochemical studies of lateral flow assay test results for procalcitonin detection

2021 ◽  
Author(s):  
Yachana Gupta Gupta ◽  
Kalpana ◽  
Aditya Sharma Ghrera
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Qualitative Analysis ◽  
Test Line ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Quantitative Detection ◽  
Cyclic Voltammograms ◽  
Paper Strip ◽  
Electrochemical Studies

In this study, the lateral flow assay (LFA) has been developed for the detection of bacterial infection (BI) by specific biomarker procalcitonin (PCT), without a need for complicated instrumentations and technical expertise. For the development of the assay, gold nanoparticles (AuNP) and their conjugates with antibodies specific to the model antigen PCT are assessed. Polyclonal antibody (pAb) labelled with gold nanoparticles (AuNP) to obtain the AuNP-pAb complex and the specific monoclonal antibody (mAb) have been dropped at the test zone. This complex is placed over the conjugate line of the LFA strip. In the absence of PCT or the presence of other biomarkers, the test line remained colourless, which revealed the specificity of assay towards PCT among a pool of various analytes. Herein, observations have been made through two different platforms for quantitative and qualitative analysis for the detection of PCT biomarker. The qualitative analysis has been performed on the basis of appearance red color in the test band, while for quantitative analysis, a novel approach has been adopted. Herein, the nitrocellulose membrane (paper strip) is cut out from the LFA strip and used for electrochemical studies under similar solution conditions. Different paper strips presented different cyclic voltammograms (CV) that could be correlated to varying PCT concentrations captured at the test line of the paper strip. The qualitative detection limit for PCT using this LFA was determined to be 2 ng/ml and the quantitative detection limit was 1 ng/ml. The electrochemical response studies of the paper strip by CV technique revealed the sensitivity value of 0.695 mA ng/ml.

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