A Low-Power Platform for Selective Sensing of Metals and Nutrients using Engineered Bacterial Autolysis

Clean water supply and distribution is critical to our standard of life and economy. However, across the country, heavy metal and nitrogen contamination threaten the quality of our groundwa- ter. Routine monitoring to ensure that water meets established quality standards is critical both to understanding natural and human influence on water composition in addition to providing early warnings for contamination events that could lead to adverse health effects. Current testing is mostly limited to sporadic sample collection for subsequent laboratory analysis, but these tests are costly and off-line, which makes them poorly-fit to monitor groundwater with high spatial or temporal resolution. As a result, current methods often do not capture the full complexity of how contaminants behave in the environment and are more complicated to deploy to field or hard to reach location. Given the priorities of DOE Biological and Environmental Research BER) and the general demand for cost-effective continuous sensors, the main objective of this SBIR proposal is to developa cost-effective and highly deployable selective platform that integrates electronics and engineered autolysis circuits in bacteria to real-time monitor fluctuations in arsenic, mercury, nitrate, and ammonium in water samples. Several of the BER focus areas, including the ones intended to understand the dynamics of the subsurface, terrestrial ecosystems, and watersheds, would benefit from sensors that would allow spatial and temporal mapping of contamination throughout a large area of concern. A successful outcome of this Phase I proposal would be the prototyping of the envisioned multi-strain electropocket platform capable of real-time detection of arsenic, mercury, nitrate, and ammonium in a continuous water input. A Phase II proposal would focus on field deployability and real-world performance of our electrochemical sensor in addition to tailoring our hardware and software to the needs of the DOE and commercial targets. The ability to detect simultaneously and in real-time several targets using a deployable plat- form is a major advantage of our device over existing technologies. While there are several on- line optical and electrochemical sensors on the water sensing market, they typically require large capital investments over $10-20k), have high maintenance and equipment costs, and need cum- bersome physical footprints. Our biosensor will be cost-effective, low-power, user-friendly, and capable of quickly and selectively measuring the concentration of several contaminants. Provid- ing results locally on the unit itself or transmitting results remotely, the device will dynamically monitor water sources without the need for highly trained personnel. In addition, the small size and weight of the proposed sensor will allow users to deploy many units, which will enable ac- cesibility of data in different points of need and negligible environmental footprint. The novel biosensor platform proposed here will be highly marketable to a wide range of end users from water testing facilities to environmental research groups, as it will meet the increasing need for data to inform management decisions in water monitoring and remediation efforts at waste sites.