Use this URL to cite or link to this record in EThOS:
Title: Electrochemical sensing of aerobic marine bacterial biofilms and the influence of nitric oxide attachment control
Author: Werwinski, Stephane
ISNI:       0000 0004 2727 0588
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2011
Availability of Full Text:
Access from EThOS:
Access from Institution:
An attractive alternative to ineffective and inefficient biocide dosing strategies for seawater piping systems would be to monitor, quantitatively evaluate and then induce biofilm disruption when necessary using an environmentally friendly biocide. The aim of the present Ostl and EPSRC funded project is to (i) sense for the presence of bacterial biofilms on metallic surfaces within seawater handling systems (e.g. heat exchangers, pipework, pumps and valves) by deploying a sensor technology to ultimately disrupt biofilms matrix and to (ii) qualitatively and quantitatively assess the extent of bacterial fouling. An electrochemical sensor using a 0.2 mm diameter gold electrode was characterised in abiotic and biotic media within a modified continuous culture flow cell under a controlled laboratory environment. Herein, electrochemical measurements by imposing electrical cathodic polarisations have demonstrated enhancement of the oxygen reduction reaction within aerobic bacterial biofilms. Importantly, electrochemical impedance spectroscopy at open circuit potential, i. e. without electrical imposed polarisation, was successfully employed to monitor initial bacterial biofilms growth and extent. An important parameter of the sensor response (capacitive component) can provide insight into quantitative evaluation of the interface, where for the first time in situ quantifiable EIS data were in good agreement with ex situ confocal microscopy analyses. Consequently, a relationship for the surface charge density (capacitive component I estimated number of sessile bacterial population) has outlined its potential use for in-service conditions. Uniquely, the electrochemical performances of a 72 h-old biofilmed gold surface dosed with nanomolar concentration; 500 nM, of the nitric oxide donor sodium nitroprusside were presented. Corroborative confocal microscopy studies have revealed effective and efficient dispersal of aerobic bacterial biofilms exposed to nitric oxide. Overall, this unique qualitative and quantitative bacterial biofilm investigation utilising a modified once through flow cell, i.e. combining microbiological and engineering expertise, represents an important first step in controlling of marine biofouling within seawater piping systems. Gold multi-microelectrode arrays located on likely biofouling positions within the seawater piping systems should be used for enhanced effectiveness of the biofilm sensing I disruption strategy.
Supervisor: Wharton, Julian Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QH301 Biology ; T Technology (General)