Biosensor and PNT Integration for Environmental Monitoring

The ‘BIO.PNT’ project, funded by the European Space Agency (ESA), has developed a water quality monitoring system that combines biosensor and positioning, navigation and timing (PNT) technologies. The system enables the association of PNT data with detected organophosphate contamination in fresh water.

Researchers from Fraunhofer and TeleOrbit delivered the project final presentation at a recent ESA-hosted event. Johannes Oeffner of Fraunhofer’s Center for Maritime Logistics and Services said “We wanted to look at different categories of biosensors and investigate the integration potential for PNT. The project brought together knowledge and expertise from a variety of scientific fields, looking at a range of different potential use cases and applications.”

Biosensors typically comprise a biological element, detecting specific biochemical reactions mediated by enzymes, immunosystems, tissues, organelles or whole cells, to detect chemical compounds. These elements are then coupled with a physical sensor or transducer that converts the biological-chemical signal into an electrical or optical signal. Biosensors are widely used in a number of applications, but are mostly seen in the healthcare field, in the monitoring and testing of medical events, in medical diagnosis. They are also used in environmental monitoring, for quality control in the pharmaceuticals and process industries, and in forensics.

Putting it together

The BIO.PNT first undertook an extensive analysis of different categories of biosensors, focusing on their potential for PNT integration. Field-effect transistor based biosensors for environmental monitoring were found to be very good candidates for combination with PNT. From there, the project developed the BIO.PNT sensor for the detection of pesticides within freshwater.

The selected bioreceptor is an organophosphate pesticide-cleaving enzyme combined with a transducer. The transducer comprises a modified field-effect transistor (FET) with amperometry, voltammetry or electrochemical impedance spectrometry (EIS).

System architecture is straightforward. One or more underwater sensor boxes contain physical biosensors for calibration and reference measurements, with pre-processing and signal processing via a microcontroller or analog front end specifically developed for the purpose. On the water’s surface, a communication box, powered by a solar panel, contains a low-power microcontroller serving as the primary control unit, and a GNSS/PNT module, with data storage handled via microSD card, and a communication module to send data to the user.

In summation, Oeffner said, “The BIO.PNT solution allows users to continuously detect organophosphate contamination in fresh water without sample preparation, in combination with PNT parameters that can be assigned to each measured value. This data would allow for environmental monitoring assessing water quality in natural ecosystems, lakes, and rivers, to locate, understand and mitigate the impact of human activities.

BIO.PNT was funded under ESA’s NAVISP program, supporting technology innovation in the European PNT industry.

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