Microbial bioelectronic sensors use living bacteria that can create an electrical signal in response to the presence of a target substance, or analyte. These types of sensors offer many advantages over other types of biosensors based on proteins and enzymes: The bacteria can perform multiple functions, survive in a variety of environments and even grow and regenerate for potential long-term use.
However, building devices using living bacteria poses several challenges. The mediators some bacteria use to send and receive electrons, creating the electric signal, can be swept away from the sensor by liquid environments researchers would want to monitor, like wastewater. Some mediators are toxic to humans or the environment. Rice University researcher Rafael Verduzco developed a safe bioelectronic sensor that allows for effective electronic communication even in liquid environments. The study was recently published in the journal Advanced Materials.
“This system uses a naturally occurring polymer chitosan, which is found in the hard outer shells of crustaceans. In our system, the chitosan also acts kind of like a shell to keep the bacteria from escaping. It is also modified to have anchor points the mediators can attach to, which are critical to transport electrons,” said Verduzco, corresponding author on the paper and the A.J. Hartsook Professor of Chemical and Biomolecular Engineering. “This material provides a flexible way to encapsulate the bacteria and enhance electronic signals. Since it’s based on a low-cost and renewable polymer, we think it has great potential for real-world applications.”
