Abstract

Quantitative, Sensitive and Multiplexed Detection of Staphylococcal Enterotoxins: The Lanthanide-based Luminescent Nanoparticle Contribution to Lateral Flow Assays

Fanny Mousseau, Post doctorate fellow, Laboratoire d'Optiques et Biosciences (LOB), INSERM U1182, CNRS UMR 7645, Ecole Polytechnique

The simple, rapid, portable, and specific detection of biomolecules and pathogens in complex media is of growing interest in many fields such as “point-of-care” medical diagnostics, food industry, environmental monitoring, etc. Lateral Flow Assays (LFAs) are a central tool in this context since they meet most of the criteria recommended by the World Health Organization for such analyses . Examples of consumer use are pregnancy tests sold in pharmacies and, more recently, antigen tests for the detection of COVID-19. However, the standard gold nanoparticle-based LFAs lack sensitivity and generally do not provide quantitative measurements or simultaneous detection of several targets. In order to overcome these limitations, we combined a simple homemade reader coupled to a smartphone with the remarkable optical properties of lanthanide ions using luminescent YVO4:Eu nanoparticles as probes. First, quantitative analysis of the luminescent strips were carried out to detect four staphylococcal enterotoxins responsible for food poisoning. We demonstrated a gain in sensitivity of more than one order of magnitude compared to the reference LFA, approaching or surpassing the ELISA sensitivity. Second, by spatial multiplexing, three toxins were simultaneously detected without any loss of sensitivity. Our method thus constitutes a powerful and versatile approach to detect multiple proteins and could be the basis for future sensitive and portable bioassays or diagnostic tests.