Microfluidic Microbial Bioelectrochemical Systems: An Integrated Investigation Platform for a More Fundamental Understanding of Electroactive Bacterial Biofilms

Abstract

It is the ambition of many researchers to finally be able to close in on the fundamental, coupled phenomena that occur during the formation and expression of electrocatalytic activity in electroactive biofilms. It is because of this desire to understand that bioelectrochemical systems (BESs) have been miniaturized into microBES by taking advantage of the worldwide development of microfluidics. Microfluidics tools applied to bioelectrochemistry permit even more fundamental studies of interactions and coupled phenomena occurring at the microscale, thanks, in particular, to the concomitant combination of electroanalysis, spectroscopic analytical techniques and real-time microscopy that is now possible. The analytical microsystem is therefore much better suited to the monitoring, not only of electroactive biofilm formation but also of the expression and disentangling of extracellular electron transfer (EET) catalytic mechanisms. This article reviews the details of the configurations of microfluidic BESs designed for selected objectives and their microfabrication techniques. Because the aim is to manipulate microvolumes and due to the high modularity of the experimental systems, the interfacial conditions between electrodes and electrolytes are perfectly controlled in terms of physicochemistry (pH, nutrients, chemical effectors, etc.) and hydrodynamics (shear, material transport, etc.). Most of the theoretical advances have been obtained thanks to work carried out using models of electroactive bacteria monocultures, mainly to simplify biological investigation systems. However, a huge virgin field of investigation still remains to be explored by taking advantage of the capacities of microfluidic BESs regarding the complexity and interactions of mixed electroactive biofilms.

Microbial Electrochemical Systems: Principles, Construction and Biosensing Applications

“…MESs were shown to be the most effective way for studying and understanding the role of the conductive solid surfaces and the environment in biofilm formation [4,72,73]. Bioelectrochemical analysis of the biofilm formation at different electrode modifiers was conducted to understand the influence of the electrode materials on the biofilm progression [11,74].…”

Recent advances in bio-electrochemical system analysis in biorefineries

“…Such a practice provides secure data to be received and electrochemical reaction kinetics reported separately at anodes and cathodes. Up to now, just rare classes of three-electrode arrangements have been developed within microfluidic BESs [198].…”

Bacterial Competition for the Anode Colonization under Different External Resistances in Microbial Fuel Cells

“…The selection of EAB during biofilm formation on the anode is a crucial step for improving the performance of MFCs. Several research groups have reported different strategies to improve EAB enrichment by using various factors that shape biofilm formation, such as substrate, temperature, pH, flow rate, anode potential, anode surface topology and surface chemistry [6][7][8]. One of the most investigated factors is the external resistance (R ext ) used in the external circuit of the MFC to control the electron flow from the anode to the cathode.…”