Ultrasensitive detection of microbial cells using magnetic focus enhanced lateral flow sensors

Ren, Wen; Cho, Il Hoon; Zhou, Zhongwu; Irudayaraj, Joseph

doi:10.1039/c5cc10240e

Cited by 51 publications

(43 citation statements)

References 26 publications

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“…To confirm the effect of magnetic forces on retarding the movement of particles along the membrane, the particle transit time in a 6-cm unmodified Whatman FF80HP membrane (from sample application to visually-observed arrival of particles at the absorbent pad) was measured in the presence and absence of the magnetic field. Without the magnetic field, the transit took 22 ± 2 minutes (n = 3); When the electromagnets were applied (10-second on/10-second off pulses at 14 V, 0.03 Tesla field strength, electromagnets at top upstream and bottom midstream positions in unsynchronized mode) the transit time increased from 22 to 28 ± 2 minutes (n = 3), confirming that electromagnets can retard the movement of the particles, as previously suggested [ 28 ].…”

Section: Resultssupporting

confidence: 77%

“…Recently Ren et al . (2016) demonstrated that the limit of detection (LoD) of an LFA using magnetic particle reporters could be improved by positioning a permanent magnet under the test line, and suggested that this was because of a longer target-capture line interaction time, leading to increased reporter capture at the detection zone [ 28 ]. It also has previously been shown that delaying the sample flow in gold particle LFAs using strips with incorporated hydrophobic barriers [ 29 ] or focusing target-gold reporter complexes into a thin band and transporting them to the test line using isotachophoresis [ 30 ] can improve the LoD of gold particle LFAs.…”

Section: Introductionmentioning

confidence: 99%

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

Jacinto

Trabuco

et al. 2018

PLoS ONE

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Lateral flow assays (LFAs) are a widely-used point-of care diagnostic format, but suffer from limited analytical sensitivity, especially when read by eye. It has recently been reported that LFA performance can be improved by using magnetic reporter particles and an external magnetic field applied at the test line. The mechanism of sensitivity/performance enhancement was suggested to be concentration/retardation of reporter particles at the test line. Here we demonstrate an additional mechanism of particle relocation where reporter particles from the lower depths of the translucent LFA strip relocate to more-visible locations nearer to the top surface, producing a more visible signal. With a magnetic field we observed an improvement in sensitivity of human chorionic gonadotropin (hCG) detection from 1.25 ng/mL to 0.31 ng/mL. We also observed an increase of the color intensity per particle in test lines when the magnetic field was present.

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Section: Resultssupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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

Jacinto

Trabuco

et al. 2018

PLoS ONE

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“…E. coli O157:H7 as the most common shiga toxin enterotoxigenic (STEC) foodborne pathogen serves as a model for proof of concept, resulting in a state of the art with remarkable improvement over the years gaining more sensitivity, and specificity by taking advantage of novel nanomaterial properties and alternative capture biomolecules. Recent reports of lateral flow modifications excel with enhanced response detecting concentrations as low as 537 colony forming units (CFU) mL −1 in ground beef by using immunochromatographic assay with gold nanoparticle‐assisted enzyme signal amplification, 200 CFU mL −1 (in pineapple juice) by immunomagnetic sample concentration, and 100 CFU mL −1 (in phosphate buffer) using a traditional lateral flow assay with controlled size and dispersion of the gold nanoparticles . When the complexity of the real food matrix tested increases, the limit of detection (LOD) tends to dramatically decrease due to the noise to signal ratio, posing an obstacle for validation under real conditions; In 2017, Jin and collaborators presented gold decorated polystyrene beads as a novel label material for immunocapture, achieving a limit of detection of 500 CFU mL −1 in ground beef without enrichment …”

Section: Introductionmentioning

confidence: 99%

Inkjet Printed Nanopatterned Aptamer‐Based Sensors for Improved Optical Detection of Foodborne Pathogens

Díaz‐Amaya

Zhao

Lin

et al. 2019

Small

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The increasing incidence of infectious outbreaks from contaminated food and water supply continues imposing a global burden for food safety, creating a market demand for on‐site, disposable, easy‐to‐use, and cost‐efficient devices. Despite of the rapid growth of biosensors field and the generation of breakthrough technologies, more than 80% of the platforms developed at lab‐scale never will get to meet the market. This work aims to provide a cost‐efficient, reliable, and repeatable approach for the detection of foodborne pathogens in real samples. For the first time an optimized inkjet printing platform is proposed taking advantage of a carefully controlled nanopatterning of novel carboxyl‐functionalized aptameric ink on a nitrocellulose substrate for the highly efficient detection of E. coli O157:H7 (25 colony forming units (CFU) mL−1 in pure culture and 233 CFU mL−1 in ground beef) demonstrating the ability to control the variation within ±1 SD for at least 75% of the data collected even at very low concentrations. From the best of the knowledge this work reports the lowest limit of detection of the state of the art for paper‐based optical detection of E. coli O157:H7, with enough evidence (p > 0.05) to prove its high specificity at genus, species, strain, and serotype level.

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“…Until now, biosensors based on various analytical techniques and strategies have been reported with improved detection sensitivity. [1][2][3][4][5][6][7][8] However, due to the limited detection capability in large volume samples, there is still a big gap between the reported sensitivity and the regulatory requirement. To bridge the gap, steps to enrich bacteria from samples is usually performed using methods such as culturing, filtration and concentration with NPs.…”

Section: Introductionmentioning

confidence: 99%

A net fishing enrichment strategy for colorimetric detection of E. coli O157:H7

Ren

Liu

Irudayaraj

2017

Sensors and Actuators B: Chemical

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The strict regulatory requirements for pathogen monitoring in food systems to ensure safety demands that the detection method can recognize small numbers of pathogens. Although significant efforts on the development of biosensors have been reported with marked improvement in sensitivity, appropriate enrichment strategies are still needed in a detection scheme. Herein we proposed a unique strategy for the enrichment of pathogens, based on a concept termed as net fishing, to capture target bacteria with antibodies functionalized on porous substrates to fish the target from samples. Because of their large surface area porous nitrocellulose membranes (NC membranes) were used as substrates for target capture. By immersing the antibody modified NC membrane into liquid samples and upon mixing, we expect to anchor target pathogens on the membrane due to the specific interaction between antibody and target, where the nonspecific enrichment could be reduced compared to methods such as filtration. Meanwhile the net fishing enrichment requires 2 hours, less than common culture methods. An enzyme enhanced procedure was performed with the NC membrane after the capture to obtain colorimetric signal. Gold nanoparticle (GNP) probes conjugated with horseradish peroxidase (HRP) and antibody were used to label capture target bacteria, and the presence of pathogens was determined by the colorimetric signal generated from HRP catalyzed TMB reaction. With E. coli

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Ultrasensitive detection of microbial cells using magnetic focus enhanced lateral flow sensors

Cited by 51 publications

References 26 publications

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

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

Inkjet Printed Nanopatterned Aptamer‐Based Sensors for Improved Optical Detection of Foodborne Pathogens

A net fishing enrichment strategy for colorimetric detection of E. coli O157:H7

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