A Microfluidic Biosensor Platform for Real-Time Water Monitoring

Access to clean, reliable water supplies is critical to our quality of life and our economy, yet across the country thousands of hazardous waste sites are so heavily contaminated that the underlying groundwater doesn’t meet drinking water standards. Measuring contamination in the environment is critical to human health and to the DOE Biological and Environmental Research (BER) program’s goal to understand complex subsurface systems, but current testing is mostly limited to sporadic sample collection for laboratory analysis. Not only is this process costly, but it is inefficient, making it difficult 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. We are developing the first customizable in-line biosensor platform that will use a microfluidic device to house many different sensor strains, each with the ability to detect a different water contaminant on a continuous basis. Each spatially-isolated strain will fluoresce when its specific target is present in the water, and we have engineered a customized optics and image processing platform that translates these cell signals into a quantitative information about the level of each target present. A single microfluidic cartridge can take continuous data for at least a month with no intervention, and data can be transmitted remotely to a user-friendly interface. In Phase I, we demonstrated technical feasibility by developing and characterizing new sensor strains for nitrate, nitrite, ammonium, and phosphate. We also developed a mass-manufacturable microfluidic platform for housing many individual sensor strains, and we used this platform to collect hundreds of hours of calibration data to develop computational tools to correlate fluorescent signals with contaminant levels. In Phase II, we propose a two year work plan that will result in a robust, field-deployable biosensor platform that can detect a suite of heavy metals and nutrients in outdoor environments for over a month with no intervention. In addition, by performing field trials with partners in two different disciplines, we aim to demonstrate the value that our sensor can provide to a diverse range of applications. In terms of broad marketability, there is a critical need for novel in-water nutrient sensors in wastewater, agricultural, and environmental monitoring settings. In addition to working with an academic research group to demonstrate the benefits of our sensor for environmental monitoring, we plan to partner with an industrial algae producer to demonstrate the ability of our sensorto tie into an intelligent nitrate dosing system to boost biomass growth and therefore revenues. Ultimately, our goal is to develop sensing technology that is not only marketable but that provides a broader public benefit. The nation’s groundwater resources face many serious threats including industrial waste, agricultural runoff, sewage, and toxic chemicals used in processes like fracking. We believe that addressing the impacts and costs of water contamination can be greatly assisted by the availability of affordable continuous monitoring. An advanced sensor that addresses current limitations would allow monitoring to become more affordable, continuous, and field-deployable. Therefore, not only will the novel biosensor platform that we are developing be highly marketable to a wide range of end-users, it will meet the increasing need for data to address the increasing public awareness of the health risks associated with contaminated drinking water.