Label-free bimodal waveguide immunosensor for rapid diagnosis of bacterial infections in cirrhotic patients
Maldonado, Jesús (Institut Català de Nanociència i Nanotecnologia)
González-Guerrero, Ana Belén (Institut Català de Nanociència i Nanotecnologia)
Dominguez, Carlos (Institut de Microelectrònica de Barcelona)
Lechuga, Laura M (Institut Català de Nanociència i Nanotecnologia)

Data:	2016
Resum:	Spontaneous bacterial peritonitis is an acute bacterial infection of ascitic fluid; it has a high incidence in cirrhotic patients and it is associated with high mortality. In such a situation, early diagnosis and treatment is crucial for the survival of the patient. However, bacterial analysis in ascitic fluid is currently based on culture methods, which are time-consuming and laborious. We report here the application of a photonic interferometer biosensor based on a bimodal waveguide (BiMW) for the rapid and label-free detection of bacteria directly in ascitic fluid. The device consists of a straight waveguide in which two modes of the same polarization interfere while interacting with the external medium through their evanescent fields. A bimolecular event occurring on the sensor area of the device (e. g. capturing bacteria) will differently affect each light mode, inducing a variation in the phase of the light exiting at the output of the waveguide. In this work, we demonstrate the quantitative detection of Bacillus cereus in buffer medium and Escherichia coli in undiluted ascitic fluid from cirrhotic patients. In the case of Bacillus cereus detection, the device was able to specifically detect bacteria at relevant concentrations in 12. 5 min and in the case of Escherichia coli detection, the analysis time was 25 min. Extrapolation of the data demonstrated that the detection limits of the biosensor could reach few bacteria per milliliter. Based on the results obtained, we consider that the BiMW biosensor is positioned as a promising new clinical tool for user-friendly, cost-effective and real-time microbiological analysis.
Ajuts:	Ministerio de Ciencia e Innovación TEC2012-34280 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-624 Ministerio de Economía y Competitividad SEV-2013-0295
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Matèria:	Bimodal waveguide biosensor ; Label-free immunoassay ; Bacillus Cereus ; Escherichia coli ; Ascitic fluid
Publicat a:	Biosensors & bioelectronics, Vol. 85 (November 2016) , p. 310-316, ISSN 1873-4235

DOI: 10.1016/j.bios.2016.04.095

Preprint 20 p, 835.0 KB

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