Blessing in disguise: a protocol to quantify biofouling effects on drinking water electrochemical sensors is a gateway to investigate biofilm using electroanalytival methods

Provision of clean drinking water is regarded as being the most significant positive intervention in human health and it plays a significant role in supporting global health. Population growth, economic development and climate change all drive urbanisation and increase demand for clean water and the infrastructure for its delivery. As demand for clean water increases, so will the pressure to ensure its safety. Indwelling sensor networks offer real-time, long-term and intelligent monitoring system, and would enable optimisation of networks for quality. Electrochemical sensors are inexpensive and simple to construct and operate. However, prolonged exposure of the sensors to water causes biofouling which compromise their performance even in weeks or days, making early detection of performance failure critical. By using a combination of electroanalytical methods (cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy and hydrodynamic voltammetry) we can quantify the mass transport and kinetics effects of the first six days old biofilm layer to electrode reactions. We used agarose hydrogels and cellulose acetate layer as model biofilms to provide rapid and simplified characterisation of early fouling effects which then compared with lab grown biofilm of Pseudomonas fluorescens. We present a protocol forin situdiagnosis of electrochemical sensors fouling during early stages of biofouling. We also demonstrate that the behaviour of lab grown biofilm can be approached by using a simple model made of hydrogels (i.e. agarose) or a dried layer of an organic solution (i.e. cellulose acetate) which provides a potential application in other fields beyond environmental sensors development such as infectious disease and novel antibiotic researches.