Integrated Nanomembrane based Chemical Field Effect Transistors (ChemFETs) for Groundwater Monitoring

The groundwater resources are currently not only threatened by excess use, but also by industrial, agricultural, and municipal sources of contamination. The autonomous and continuous monitoring of groundwater quality and biogeochemical activities is urgently needed to ensure a healthy subsurface environment. The accurate detection and spatial mapping of relevant oxidation states of iron, manganese, copper or other inorganic materials would be used to study the water quality and the chemical cycles within multi-phase flows and at the water-sediment interface. Traditional systems are usually costly, bulky and time consuming, so not suitable for field deployment for the detection and mapping of redox sensitive chemicals. The proposed nanomembrane-based ChemFET sensors offer significantly improved chemical sensitivity and selectivity, combined with the wireless communication of data from multiple small patchable, attachable, portable, or flowable sensors to fixed or mobile receivers. High selectivity can be achieved by designing self-assembled bonding for iron, manganese, copper, and other redox sensitive metals. Multiple sensor devices can be configured in a small, lightweight and low cost array to analyze multiple sensor targets simultaneously. This DOE program would develop the wireless sensors for use in the analysis of hydrobiogeochemical and microbial processes for subsurface monitoring facilities, and remote field sites. The company would first fabricate prototype nanomembrane ChemFET sensor elements, and then design and synthesize ESA thin films and chemical-specific ionophores for the selective detection of targeted redox sensitive elements such as iron, manganese and copper. The performance of prototype sensor devices would then be demonstrated. Commercial Applications and Other Benefits Multiple small-size and low-cost sensors could be distributed over an area to allow 1) spatial mapping of metal targets, as well as 2) real-time updating of metal concentration map as local conditions may change over time. The proposed nanomembrane redox sensitive metal analysis tool would be a viable commercial product for eco system monitoring.