Browsing by Author "Garvey, Gavin"
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Item Enhancement of lateral flow assay performance by electromagnetic relocation of reporter particles(PLoS ONE, 2018-01) Jacinto, Maria Joao; Trabuco, Joao R. C.; Vu, Binh V.; Garvey, Gavin; Khodadady, Mohammad; Azevedo, Ana M.; Aires-Barros, Maria R.; Chang, Lang; Kourentzi, Katerina D.; Litvinov, Dmitri; Willson, Richard C.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.Item Flotation Immunoassay: Masking the Signal from Free Reporters in Sandwich Immunoassays(Scientific Reports, 2016-04) Chen, Hui; Hagstrom, Anna E. V.; Kim, Jinsu; Garvey, Gavin; Paterson, Andrew S.; Ruiz-Ruiz, Federico; Raja, Balakrishnan; Strych, Ulrich; Rito-Palomares, Marco; Kourentzi, Katerina D.; Conrad, Jacinta C.; Atmar, Robert L.; Willson, Richard C.In this work, we demonstrate that signal-masking reagents together with appropriate capture antibody carriers can eliminate the washing steps in sandwich immunoassays. A flotation immunoassay (FI) platform was developed with horseradish peroxidase chemiluminescence as the reporter system, the dye Brilliant Blue FCF as the signal-masking reagent, and buoyant silica micro-bubbles as the capture antibody carriers. Only reporters captured on micro-bubbles float above the dye and become visible in an analyte-dependent manner. These FIs are capable of detecting proteins down to attomole levels and as few as 106 virus particles. This signal-masking strategy represents a novel approach to simple, sensitive and quantitative immunoassays in both laboratory and point-of-care settings.Item Sensitive Detection of Norovirus Using Phage Nanoparticle Reporters in Lateral-Flow Assay(PLoS ONE, 2015-05) Hagstrom, Anna E. V.; Garvey, Gavin; Paterson, Andrew S.; Dhamane, Sagar; Adhikari, Meena; Estes, Mary K.; Strych, Ulrich; Kourentzi, Katerina D.; Atmar, Robert L.; Willson, Richard C.Noroviruses are recognized worldwide as the principal cause of acute, non-bacterial gastroenteritis, resulting in 19-21 million cases of disease every year in the United States. Noroviruses have a very low infectious dose, a short incubation period, high resistance to traditional disinfection techniques and multiple modes of transmission, making early, point-of-care detection essential for controlling the spread of the disease. The traditional diagnostic tools, electron microscopy, RT-PCR and ELISA require sophisticated and expensive instrumentation, and are considered too laborious and slow to be useful during severe outbreaks. In this paper we describe the development of a new, rapid and sensitive lateral-flow assay using labeled phage particles for the detection of the prototypical norovirus GI.1 (Norwalk), with a limit of detection of 107 virus-like particles per mL, one hundred-fold lower than a conventional gold nanoparticle lateral-flow assay using the same antibody pair.