Rapid Lab Grown Biofilm As a Tool for Engineering Sensor Networks of Biofouling-Resistant Electrochemical Sensors

Abstract

Robust and rapid biofilm formation is not only a major interest in the development of microbial fuel cell, but it is also be of relevance to the development of indwelling environmental sensor networks. Sensor networks offer real-time, online and long-term monitoring which is an attractive monitoring strategy for water industry to prepare for increasing demand for clean water due to increased urbanisation and the pressures of climate change. Sensor networks support the development of robust and managed drinking water supply networks that are essential to human health. Fouling of sensors due to biofilm formation is very common in indwelling situations and it is a major drawback in the development of sensor networks. Sensors will fail once it is fouled and it can happen in just a couple days or weeks. Engineering robust sensor networks begins with designing a biofouling resistant sensors. Electrochemical sensors are inexpensive and simple to construct and operate, and it is widely used in water industry. Understanding how biofilms affect electrochemical sensor performance is important to enable detection of malfunction in situ, and can inform the development of methodology to restore the performance in situ. Networks can consist of hundreds of sensors and automated restoration of function in biofouled sensors is thus essential. Lab-based models play a vital role. However, it is not always possible to recreate the real conditions for biofilm formation in the lab and it can take too long for it to form. In a situation in which it is not possible to build a permanent testing setup, rapid lab grown biofilm is desirable. Adhesion of pioneering bacterial cells to the surface is the most crucial step in biofilm formation. Adhesion of cells to surfaces can be accelerated by altering the surface chemistry of the surfaces. One way to do this is by plasma treatment of the surface. Formation of a lawn of biofilm is desirable to model early biofouling event. Polysaccharide production that forms the extrapolymeric substance (EPS) of biofilm can be induced by common biocidal substance such as triclosan. Electrochemically generated local concentration of hydrogen peroxide has similar consequences. In this work, we show that it is possible to form some coverage of biofilm on electrode surface in just two hours, which represents early biofouling event. It has a potential for the development of rapid lab grown biofilm that can be useful in developing fail-proof sensor networks.