Combining gas vesicle acoustic contrast agents with field-deployable GHz frequency ultrasonic chips to detect gene expression in sentinel microorganisms

Continuous multi-modal measurements of the physical, chemical, and biological properties of soil are key to the advancement of agriculture, farming, and the study of the soil microbiome. Here, we demonstrate that the Geegah GHz imaging platform can detect changes in the acoustic impedance of bacterial colonies due to the presence of gas vesicle contrast agents. We couple the production of these contrast agents to an external nutrient stimulus, further highlighting that the imager may be used to sense gene expression changes in living organisms. This proof-of-concept experiment unlocks future avenues to measure biological properties of soil by coupling the natural sensing capabilities of soil microorganisms with the Geegah GHz imaging platform by way of gas vesicle genetic circuits.