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Enhancing the signal of lateral flow immunoassays by using different developing methods
Journal article   Peer reviewed

Enhancing the signal of lateral flow immunoassays by using different developing methods

Jia Li, David J McMillan and Joanne Macdonald
Sensors and Materials, Vol.27(7), pp.549-561
2015
url
https://doi.org/10.18494/SAM.2015.1090View
Published Version

Abstract

nucleic acid lateral flow sandwich immunoassay gold nanoparticles
Lateral flow immunoassay devices are potential biosensors for point-of-care diagnostics. However, these devices are limited by low analytical sensitivity when coupled with a visual colorimetric signal. Here, we analyzed key parameters related to nucleic acid lateral flow performance and related this to the analytical theory behind lateral flow functionality. In particular, we predicted a set of different physical running methods to optimize the assay signal intensity by ensuring higher binding of the signal molecules to the DNA. We found that a double-run method improved the assay signal intensity on average by approximately 50%, and a fully absorbed conjugate pad method came close to the double-run signal efficacy at high DNA concentrations. Our results demonstrate that even when the signal molecule is supplied in excess, a significant proportion of analytes bind to the detection antibody in a colorless complex. The lowest detection limits achieved were 0.1 picomole for detection using an anti-Cy5 antibody and 0.01 picomole for the detection using an anti-Texas Red antibody. Our double-run method improvement is generic, does not require additional reagents and equipment, reduces assay costs compared to the fully absorbed method, and is applicable to other lateral flow immunoassays.

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