A novel biohybrid electronic device architecture for environmental and physiological sensing

The Bacterial Flagellar Motor is one of nature's rare rotary molecular machines. It enables bacterial swimming and is a key part of the bacterial chemotactic network that enables bacteria to direct their movement given the chemical environment. This network is one of the best-studied chemical signalling networks in biology, sensing down to nanomolar concentrations of specific chemicals on the time scale of seconds. The motor's rotational speed is linearly proportional to the bacterial electrochemical gradients, most notably of proton or sodium ions, while its direction is regulated by the chemotactic network. Recently, it has been discovered that the motor is also a mechanosensor. Given these properties, the motor has the potential to serve as a multimodal biosensor with unprecedented speed and sensitivity, and thus a tool for characterizing and studying the external environment, but also bacterial physiology itself. However, at the resolution needed, motor speed and rotational direction are currently detected optically, one motor at a time. A step-change in harnessing the unprecedented potential of this rotary molecular machine would be to detect each motor's rotation electrically and with high throughput. Here I propose to achieve this by specifically attaching individual bacteria to a precise location on the surface and testing two electrical means of detecting the motor's rotation: an integrated circuit and a graphene surface. The detection method will also be employed to fully characterize the three different sensing modalities offered by the flagellar motor: that of cells own physiology, of mechanical forces and of a given set of chemicals. The success of the project we will enable portable biosensor-on-a-chip configuration of the motor speed and rotational direction detection, which can be a game-changer in the biosensing field.