Simple geometrical modifications for substantial color intensity and detection limit enhancements in lateral-flow immunochromatographic assays

Zadehkafi, Ali; Siavashi, Majid; Asiaei, Sasan; Bidgoli, Mostafa Rabbani

doi:10.1016/j.jchromb.2019.01.019

Cited by 13 publications

(7 citation statements)

References 45 publications

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“…Several fabrication methods have been proposed to modify the strip to reduce the flow rate in the LFA strip. The geometrical modifications of the LFA strips can be achieved by cutting the LFA strip into specific shapes [18,19] or using laser patterned photopolymer to create a barrier on nitrocellulose (NC) membrane [20] to control the flow rates in the LFA strips. Additionally, flow-interrupting materials can be inserted or embedded in the LFA strip to reduce the flow rate [21].…”

Section: Introductionmentioning

confidence: 99%

Pressed Lateral Flow Assay Strips for Flow Delay-Induced Signal Enhancement in Lateral Flow Assay Strips

Park

Shin

2022

BioChip J

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This paper proposes that the signal intensity of a lateral flow assay (LFA) strip can be increased by pressing the top of the strip, effectively reducing its flow rate. The reduced flow rate allows more time for antigen-antibody interactions to occur, resulting in increased signal intensity and an improved detection limit. To assess the potential of the pressed LFA (pLFA) strip, C-reactive protein (CRP) diluted in phosphate-buffered saline (PBS) and serum is detected, affording signal enhancement and a lowered limit of detection. Additionally, to show that the signal enhancement by pressure-induced flow delay applies to existing LFA products, commercially available COVID-19 antigen test strips are pressed, and signal enhancement is observed. Lastly, we show that the signal intensity of COVID-19 LFA kits can be increased by approximately two-fold at maximum by applying pressure on top of the manufactured product. This study suggests that pressed LFA strips can be used to reduce the chances of determining ambiguous signals as false-negative results and can potentially improve the detection sensitivity.

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Section: Introductionmentioning

confidence: 99%

Pressed Lateral Flow Assay Strips for Flow Delay-Induced Signal Enhancement in Lateral Flow Assay Strips

Park

Shin

2022

BioChip J

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“…4C) [30]. In the same line, recent works demonstrated that by decreasing the detection pad width and increasing the distance between the conjugate and the detection pads, a 2-fold better sensitivity is reached [32]. However, modification of the detection pad architecture is an amplification strategy limited by the compromise between the amplification pursuit and the compatibility with the available cartridge holders and strip readers.…”

Section: General Design/architecturementioning

confidence: 99%

Strip modification and alternative architectures for signal amplification in nanoparticle-based lateral flow assays

Díaz‐González

Escosura‐Muñiz

2021

Anal Bioanal Chem

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Nanoparticle (NP)-based lateral flow assay (LFA) technology has outstanding characteristics that make it ideal for point-of-care bioanalytical applications. However, LFAs still have important limitations, especially related to sensitivity, which is in general worse than that of other well-established bioassays such as ELISA or PCR. Many efforts have been made for enhancing the sensitivity of LFAs, mainly actuating on the nanoparticle labels and on alternative optical detection modes. However, strip pads modification for such a purpose is an incipient vast field of research. This article gives a brief overview on the recent advances proposed for signal amplification actuating on different pads and the general architecture of the LFA strips. Such strategies offer universal tools that can be adapted to any LFA, independently of the kind of sample, analyte, and label. The principles of the different strategies developed to achieve novel signal amplification and sensitive detection are discussed, and some examples of relevant approaches are highlighted, together with future prospects and challenges.

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“…Narrowing-width pads, where the wicking velocity is higher than normal strips, reduce the LOD by half, to 5 mIU/mL, whereas widening the detection pad might achieve color intensity of up to 150%. An optimal distance from the conjugate pad to the test line augments the highest possible color intensity by up to four times [ 184 ]. A physical–chemical coupling method using dissoluble saline barriers was developed to enhance LFA sensitivity.…”

Section: Pads Engineering-based Signal Amplificationmentioning

confidence: 99%

Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

Hoang

Phan

et al. 2021

Biomedicines

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Paper-based analytical devices (PADs) have emerged as a promising approach to point-of-care (POC) detection applications in biomedical and clinical diagnosis owing to their advantages, including cost-effectiveness, ease of use, and rapid responses as well as for being equipment-free, disposable, and user-friendly. However, the overall sensitivity of PADs still remains weak, posing a challenge for biosensing scientists exploiting them in clinical applications. This review comprehensively summarizes the current applicable potential of PADs, focusing on total signal-amplification strategies that have been applied widely in PADs involving colorimetry, luminescence, surface-enhanced Raman scattering, photoacoustic, photothermal, and photoelectrochemical methods as well as nucleic acid-mediated PAD modifications. The advances in signal-amplification strategies in terms of signal-enhancing principles, sensitivity, and time reactions are discussed in detail to provide an overview of these approaches to using PADs in biosensing applications. Furthermore, a comparison of these methods summarizes the potential for scientists to develop superior PADs. This review serves as a useful inside look at the current progress and prospective directions in using PADs for clinical diagnostics and provides a better source of reference for further investigations, as well as innovations, in the POC diagnostics field.

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Simple geometrical modifications for substantial color intensity and detection limit enhancements in lateral-flow immunochromatographic assays

Cited by 13 publications

References 45 publications

Pressed Lateral Flow Assay Strips for Flow Delay-Induced Signal Enhancement in Lateral Flow Assay Strips

Pressed Lateral Flow Assay Strips for Flow Delay-Induced Signal Enhancement in Lateral Flow Assay Strips

Strip modification and alternative architectures for signal amplification in nanoparticle-based lateral flow assays

Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

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