Enhancement of lateral flow assay performance by electromagnetic relocation of reporter particles

Jacinto, Maria João; Trabuco, João R. C.; Vu, Binh; Garvey, Gavin; Khodadady, Mohammad; Azevedo, Ana M.; Aires-Barros, M. Raquel; Chang, Long; Kourentzi, Katerina; Litvinov, Dmitri; Willson, Richard C.

doi:10.1371/journal.pone.0186782

Cited by 27 publications

(15 citation statements)

References 30 publications

(25 reference statements)

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“…The loss of the optical signal depends on the properties of the material but is usually estimated [93] as about one order of magnitude. In this regard, the work of Jacinto et al [117] is extremely interesting. They offer an electromagnetic relocation of reporter particles for amplifying an optical signal and describing the fourfold reduction in the detection limit of human chorionic gonadotropin.…”

Section: Proper Response For Lfiamentioning

confidence: 97%

Ways to Reach Lower Detection Limits of Lateral Flow Immunoassays

Zherdev¹,

Dzantiev²

2018

Rapid Test - Advances in Design, Format and Diagnostic Applications

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This chapter considers factors influencing sensitivity of lateral flow immunoassay and modern developments that are focused on reaching lower detection limits. The existing variety of proposed approaches is classified in accordance with the "big five rules" for these assays, including proper sample, receptor, interaction, response, and output. The solutions for rapid extraction of target analytes and preventing negative influence of extractants are considered. Role to antibodies affinity and specificity is characterized. Potential of alternate bioreceptor molecules is discussed. Immunoreactants' compositions, concentrations, and locations on the test strip are characterized as factors determining assay parameters. The existing variety of labels is compared in terms of their optical and alternate registration. Tools to modulate a sequence of analytical reactions and to form aggregates of the detected labels are considered. The discussed approaches are illustrated through developments of test strips for detection of mycotoxins, veterinary drugs, and other analytes.The overall design of the immunochromatographic test strip is shown in Figure 1. It is a composite of several membranes of different structures and porosities, fixed on a support. The bundling of the test strip can vary, so it makes sense to consider its design based on what analytical tasks are being performed on its different sites.A. Typically, the lower portion of the test strip contains a sample pad. It ensures the absorption of sample components, in which the presence of the target analyte is checked.B. The following is a section with immunoreagents that are washed out during the analysis and move upward along with the components of the sample. As a rule, a conjugate pad forms this zone. It contains a conjugate of antibodies against the target analyte with a nanodispersed label-particles of colored latex, colloidal gold, and so on.The next two sections are located on the main working membrane of the test strip. C.First, there is a zone along which the movement of the absorbed components of the sample and the washed immunoreagents continues. During this movement, immune reactions occur, and specific intermolecular complexes are formed. D.Next, a mixture of reacted and unreacted molecules enters the binding area with immobilized immunoreagents. Depending on whether the target analyte was present in the sample and in what amount, binding of labeled immune complexes occurs in certain areas (in the traditional case, with the formation of narrow colored lines). Usually, additional reagents are located here to control the functionality of the test system. E. The upper part of the test strip with the final pad, usually structurally similar to the sample pad, ensures the further movement of the reaction mixture under the action of capillary forces and the washing of unreacted components from the underlying areas. These processes allow the label's binding to be evaluated correctly.Membrane components of the test strip are fixed on a plastic support and partia...

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Section: Proper Response For Lfiamentioning

confidence: 97%

Ways to Reach Lower Detection Limits of Lateral Flow Immunoassays

Zherdev¹,

Dzantiev²

2018

Rapid Test - Advances in Design, Format and Diagnostic Applications

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“…Detection of multiple analytes is also made easier and more precise with this technology. The use of fluorophore, QDot or magnetic particles as reporter particles, are typical efficient strategies to enhance the detection sensitivity [28]. Vashist et al [29] also mentions, among others, the use of acoustic fields and the application of thermal contrasting techniques.…”

Section: J Systems Of Integration Of Detection Processmentioning

confidence: 99%

Point-of-Care Testing Devices for Heart Failure Analyzing Blood and Saliva Samples

Tripoliti

Fotiadis

Ioannidou

et al. 2020

IEEE Rev. Biomed. Eng.

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Heart failure (HF) is the most rapidly growing cardiovascular condition with an estimated prevalence of >37.7 million individuals globally. HF is associated with increased mortality and morbidity and confers a substantial burden, in terms of cost and quality of life, for the individuals and the healthcare systems, highlighting thus the need for early and accurate diagnosis of HF. The accuracy of HF diagnosis, severity estimation and prediction of adverse events has been improved by the utilization of blood tests measuring biomarkers. The contribution of biomarkers for HF management is intensified by the fact that they can be measured in short time at the point-of-care. This is allowed by the development of portable analytical devices, commonly known as Point-of-Care Testing (POCT) devices, exploiting the advancements in the area of microfluidics and nanotechnology. The aim of this review paper is to present a review of POCT devices used for the measurement of biomarkers facilitating decision making when managing HF patients. The devices are either commercially available or in the form of prototypes under development. Both, blood and saliva samples are considered. The challenges concerning the implementation of POCT devices and the barriers for their adoption in clinical practice are discussed.

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“…In this study, an ultrahigh-sensitivity inductive transducer, the femtoMag, designed for the detection and quantification of superparamagnetic nanoparticle reporters immuno-captured in the volume of the test line of an LFA membrane, is demonstrated. Magnetic reporters provide a number of unique advantages over their optical counterparts: (1) magnetic fields do not interact with biological materials, so magnetic field-based detection is immune to signal degradation and distortion inherent to optical detection; (2) magnetic fields are not affected by LFA media, so every magnetic reporter within the test line volume contributes to detection; and (3) the properties of magnetic reporters can be tuned to match the biomarkers to optimize trapping efficiency and detection [10][11][12]. The femtoMag also provides a number of technological advancements over the current state-of-the-art magnetic biosensor technologies, including (1) volumetric detection, (2) high sensitivity, (3) direct quantitation, (4) easy integration with LFA technology, (5) portable electronic controls, and (6) low-cost manufacturability using conventional high-throughput PCB manufacturing technology.…”

Section: Of 11mentioning

confidence: 99%

“…A BioDot XYZ3060 was used to dispense the antibodies (at 1 µg/cm) to form the test and control lines. Test samples were prepared using hCG model protein diluted in LFA buffer (1% Tween-20, 0.5% BSA, in PBS, pH 7.4), and 10 µL of each sample was mixed with 1 µL of 200 nm Adembead reporters functionalized with mouse monoclonal anti-β hCG antibodies (#ABBCG-0402, Arista Biologicals) [12]. Blank samples with no hCG were used as controls.…”

Section: Lfa Membrane and Test Sample Preparationmentioning

confidence: 99%

PCB-Based Magnetometer as a Platform for Quantification of Lateral-Flow Assays

Khodadadi

Chang

Trabuco

et al. 2019

Sensors

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This work presents a proof-of-concept demonstration of a novel inductive transducer, the femtoMag, that can be integrated with a lateral-flow assay (LFA) to provide detection and quantification of molecular biomarkers. The femtoMag transducer is manufactured using a low-cost printed circuit board (PCB) technology and can be controlled by relatively inexpensive electronics. It allows rapid high-precision quantification of the number (or amount) of superparamagnetic nanoparticle reporters along the length of an LFA test strip. It has a detection limit of 10−10 emu, which is equivalent to detecting 4 ng of superparamagnetic iron oxide (Fe3O4) nanoparticles. The femtoMag was used to quantify the hCG pregnancy hormone by quantifying the number of 200 nm magnetic reporters (superparamagnetic Fe3O4 nanoparticles embedded into a polymer matrix) immuno-captured within the test line of the LFA strip. A sensitivity of 100 pg/mL has been demonstrated. Upon further design and control electronics improvements, the sensitivity is projected to be better than 10 pg/mL. Analysis suggests that an average of 109 hCG molecules are needed to specifically bind 107 nanoparticles in the test line. The ratio of the number of hCG molecules in the sample to the number of reporters in the test line increases monotonically from 20 to 500 as the hCG concentration increases from 0.1 ng/mL to 10 ng/mL. The low-cost easy-to-use femtoMag platform offers high-sensitivity/high-precision target analyte quantification and promises to bring state-of-the-art medical diagnostic tests to the point of care.

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Enhancement of lateral flow assay performance by electromagnetic relocation of reporter particles

Cited by 27 publications

References 30 publications

Ways to Reach Lower Detection Limits of Lateral Flow Immunoassays

Ways to Reach Lower Detection Limits of Lateral Flow Immunoassays

Point-of-Care Testing Devices for Heart Failure Analyzing Blood and Saliva Samples

PCB-Based Magnetometer as a Platform for Quantification of Lateral-Flow Assays

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