Simultaneous monitoring of Staphylococcus aureus growth in a multi-parametric microfluidic platform using microscopy and impedance spectroscopy.

O Estrada-Leypon, A Moya, A Guimera, G Gabriel, M Agut, B Sanchez, S Borros

Index: Bioelectrochemistry 105 , 56-64, (2015)

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Abstract

We describe the design, construction, and characterization of a scalable microfluidic platform that allows continuous monitoring of biofilm proliferation under shear stress conditions. Compared to other previous end-point assay studies, our platform offers the advantages of integration into multiple environments allowing simultaneous optical microscopy and impedance spectroscopy measurements. In this work we report a multi-parametric sensor that can monitor the growth and activity of a biofilm. This was possible by combining two interdigitated microelectrodes (IDuEs), and punctual electrodes to measure dissolved oxygen, K+, Na+ and pH. The IDuE has been optimized to permit sensitive and reliable impedance monitoring of Staphylococcus aureus V329 growth with two- and four-electrode measurements. We distinguished structural and morphological changes on intact cellular specimens using four-electrode data modeling. We also detected antibiotic mediated effects using impedance. Results were confirmed by scanning electrode microscopy and fluorescence microscopy after live/dead cell staining. The bacitracin mediated effects detected with impedance prove that the approach described can be used for guiding the development of novel anti-biofilm agents to better address bacterial infection. Copyright © 2015 Elsevier B.V. All rights reserved.