An Integrated Electronic Interface for Bio-electrochemical Plant-based Sensors

We describe a miniature electronic system that was designed for interacting specifically with plant-based electrochemical biosensors. This bare-bones setup manages the actuation of the biosensor, the data acquisition, and processing of the acquired data. The biosensor itself is based on a new concept especially designed for agriculture. In this biosensor, the plant itself functions as the sensor and provides a signal. Thus, the signal is directly related to the well-being and the status of the plant. This is a novel concept that has been conceived for precision agriculture. Using this specific sensor, the information is collected directly from the plant, yielding information directly related to the condition of the plant. This is in contrast with most other sensors today, which measure the physical and chemical variables of the plant's environment; e.g. water, ground, and air. The functional sensors use the expression of β-glucorinadase (GUS) in transgenic tobacco plants and transgenic tobacco and tomato cell lines. The GUS enzyme activity was detected by chronoamperometry, which yielded a measurable electrical current signal. The electronic system is built using relatively cheap off-the-shelf components: an analog potentiostat front end (AFE), a standard A/D converter (ADC), and a single board computer (SBC). The AFE interfaces with the sensor, while the SBC handles the control of the system and the data processing. The system was designed to highlight the possibility of making a complete interface to the internet at a cost of less than USD 15 today (in 2020), expecting the cost to fall dramatically in the next few years. This cost can be further reduced by connecting multiple sensors and AFEs to a single SBC, and by converting the system to an ASIC using VLSI technology.