The detection of Escherichia coli (E. coli) with the pH sensitive hydrogel nanofiber-light addressable potentiometric sensor (NF-LAPS)

By Shaibani, Parmiss Mojir; Jiang, Keren; Haghighat, Ghazaleh; Hassanpourfard, Mahtab; Etayash, Hashem; Naicker, Selvaraj; Thundat, Thomas
Published in Sensors and Actuators B: Chemical NULL 2016

Abstract

Abstract We report a simple, rapid and cost effective detection technique for Escherichia coli (E. coli) using a Light Addressable Potentiometric Sensor integrated with electrospun poly acrylic acid/polyvinyl alcohol (PAA/PVA) hydrogel nanofibers as a sensing layer (NF-LAPS). Changes in pH of the media are detected as E. coli cells ferment sugar molecules and increase acidity of the surrounding. A super-Nernstian response of a 74 mV/pH change in the NF-LAPS provides high sensitivity towards E. coli with a theoretical limit of detection (LOD) of 20 CFU/ml. The high sensitivity is associated with the pH sensitive behavior of the {NFs} on the surface. Detection of acidic species released in cellular metabolism of pathogens in the presence of carbon source renders the sensing mechanism cheaper, less time consuming and more practical than the antibody-antigen interaction based approach. Selectivity towards E. coli for applications in drinking water detection is ensured by the incorporation of d-mannose for specific binding.

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