Enhanced lateral flow immunoassay using gold nanoparticles loaded with enzymes

Claudio Parolo, Alfredo de la Escosura-Muñiz, Arben Merkoçi. Biosensors and Bioelectronics, 2013, 40, 412–416

The use of gold nanoparticles (AuNPs) as labeling carriers in combination with the enzymatic activity of the Horseradish Peroxidase (HRP) in order to achieve an improved optical lateral flow immunoassay (LFIA) performance is here presented.

Briefly in a LFIA with an immune-sandwich format AuNPs are functionalized with a detection antibody already modified with HRP, obtaining an “enhanced” label. Two different detection strategies have been tested: the first one following just the red color of the AuNPs and the second one using a substrate for the HRP (3 different substrates are evaluated), which produces a darker color that enhances the intensity of the previous red color of the unmodified AuNPs. In such very simple way it is gained sensitivity (up to 1 order of magnitude) without losing the simplicity of the LFIA format, opening the way to other LFIA applications including their on-demand performance tuning according to the analytical scenario.

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