Researchers interfaced synthetic biology with microelectronics through engineered population dynamics that regulate the accumulation of charged metabolites. They demonstrate electrical detection of the bacterial response to heavy metals via a population control circuit. They then implement this approach to a synchronized genetic oscillator where we obtain an oscillatory impedance profile from engineered bacteria. They lastly miniaturize an array of electrodes to form "bacterial integrated circuits" and demonstrate its applicability as an interface with genetic circuits. This approach paves the way for new advances in synthetic biology, analytical chemistry, and microelectronic technologies.
One of the main challenges of our approach is to reduce the response time. The sensor responds in 40 ± 10 min after triggering. The response is likely dependent on the translation of the proteins. Thus, further efforts in the analysis and new gene circuits may decrease these times. Another challenge in measuring bacterial cultures with electrodes is the long-term stability due to biofouling. Some of these processes could be a reason for the overtime divergence between turbidity and admittance. To mitigate these challenges, each experiment used a new disposable screen-printed or lithography-fabricated electrode. In addition, the population control and the interfacing of genetic lysis circuits with electronics provide an inherent antibiofouling mechanism because of the continuous clearing of the chamber after certain periods of time or after certain triggering conditions.