Office Paper Platform for Bioelectrochromic Detection of Electrochemically Active Bacteria using Tungsten Trioxide Nanoprobes

A C Marques,L Santos,R Martins,P Duarte,J M Dantas,M N Costa,A Gonçalves,C A Salgueiro,E Fortunato

doi:10.1038/srep09910

Abstract

Electrochemically active bacteria (EAB) have the capability to transfer electrons to cell exterior, a feature that is currently explored for important applications in bioremediation and biotechnology fields. However, the number of isolated and characterized EAB species is still very limited regarding their abundance in nature. Colorimetric detection has emerged recently as an attractive mean for fast identification and characterization of analytes based on the use of electrochromic materials. In this work, WO3 nanoparticles were synthesized by microwave assisted hydrothermal synthesis and used to impregnate non-treated regular office paper substrates. This allowed the production of a paper-based colorimetric sensor able to detect EAB in a simple, rapid, reliable, inexpensive and eco-friendly method. The developed platform was then tested with Geobacter sulfurreducens, as a proof of concept. G. sulfurreducens cells were detected at latent phase with an RGB ratio of 1.10 ± 0.04, and a response time of two hours.

Highlights

Active bacteria (EAB) have the capability to transfer electrons to cell exterior, a feature that is currently explored for important applications in bioremediation and biotechnology fields
The crystallographic structure of the synthesized WO3 nanoparticles was determined by X-ray diffraction (XRD) (Figure 1) and corroborated by Fourier transform infrared spectroscopy (FT-IR) (Fig. S1)
At pH 0.4 the sample shows a peak assigned to the acid tungstic (r) and two unidentified peaks (D) that are due to lattice distortions of the crystallographic structure, as previously reported for WO3 nanoparticles prepared by hydrothermal synthesis[30]

Summary

Introduction

Active bacteria (EAB) have the capability to transfer electrons to cell exterior, a feature that is currently explored for important applications in bioremediation and biotechnology fields. This allowed the production of a paper-based colorimetric sensor able to detect EAB in a simple, rapid, reliable, inexpensive and eco-friendly method. The WO3 nanoparticles were integrated in a wax-printed office paper platform as an active layer for EAB detection.

Results

Conclusion