Label-free detection of nosocomial bacteria using a nanophotonic interferometric biosensor
Maldonado, Jesús (Institut Català de Nanociència i Nanotecnologia)
Estévez, M. Carmen (Institut Català de Nanociència i Nanotecnologia)
Fernandez-Gavela, Adrian (Institut Català de Nanociència i Nanotecnologia)
González-López, Juanjo 1975- (Hospital Universitari Vall d'Hebron)
González-Guerrero, Ana Belén (Institut Català de Nanociència i Nanotecnologia)
Lechuga, Laura M (Institut Català de Nanociència i Nanotecnologia)

Títol variant:	Label-free detection of a few number of nosocomial bacteria using a nanophotonic interferometric biosensor
Data:	2020
Resum:	Nosocomial infections are a major concern at the worldwide level. Early and accurate identification of nosocomial pathogens is crucial to provide timely and adequate treatment. A prompt response also prevents the progression of the infection to life-threatening conditions, such as septicemia or generalized bloodstream infection. We have implemented two highly sensitive methodologies using an ultrasensitive photonic biosensor based on a bimodal waveguide interferometer (BiMW) for the fast detection of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), two of the most prevalent bacteria associated with nosocomial infections. For that, we have developed a biofunctionalization strategy based on the use of a PEGylated silane (silane-PEG-COOH) which provides a highly resistant and bacteria-repelling surface, which is crucial to specifically detect each bacterium. Two different biosensor assays have been set under standard buffer conditions: One based on a specific direct immunoassay employing polyclonal antibodies for the detection of P. aeruginosa and another one employing aptamers for the direct detection of MRSA. The biosensor immunoassay for P. aeruginosa is fast (it only takes 12 min) and specific and has experimentally detected concentrations down to 800 cfu mL (cfu: Colony forming unit). The second one relies on the use of an aptamer that specifically detects penicillin-binding protein 2a (PBP2a), a protein only expressed in the MRSA mutant, providing a photonic biosensor with the ability to identify the resistant pathogen MRSA and differentiate it from methicillin-susceptible S. aureus (MSSA). Direct, label-free, and selective detection of whole MRSA bacteria has been achieved, making possible the direct detection of also 800 cfu mL. According to the signal-to-noise (S/N) ratio of the device, a theoretical limit of detection (LOD) of around 49 and 29 cfu mL was estimated for P. aeruginosa and MRSA, respectively. Both results obtained under standard conditions reveal the great potential this interferometric biosensor device has as a versatile and specific tool for bacterial detection and quantification, providing a rapid method for the identification of nosocomial pathogens within the clinical requirements of sensitivity for the diagnosis of infections.
Ajuts:	Ministerio de Economía y Competitividad SEV-2017-0706
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Publicat a:	Analyst, Vol. 145, Issue 2 (January 2020) , p. 497-506, ISSN 1364-5528

DOI: 10.1039/c9an01485c

Preprint 20 p, 1.1 MB

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