Helen Dahlke, Associate Professor in Integrated Hydrologic Sciences, Department of Land, Air and Water Resources, UC Davis
Use of synthetic DNA and nanotechnology to understand hydrologic systems
For many decades, deciphering water sources, flow pathways, and residence times of water has been a focus in the field of hydrology. However, minimum detection limits, tracer expense, and the ability of watersheds to retain a memory of past tracer inputs have restricted the scale of application and the repeated or simultaneous use of most known tracers. By utilizing bio‐molecular nanotechnology developed for nano‐medicines and drug delivery, we are able to produce DNA‐labelled nano‐ and microparticle tracers for use in a myriad of environmental systems. The use of custom sequenced DNA allows for the fabrication of an enormous number of uniquely labelled tracers with identical transport properties (approximately 1.61 x 1060 unique sequences), each independently quantifiable, that can be applied simultaneously in any hydrologic system. By controlling the fabrication procedure to produce particles of custom size and charge, we are able to tag each size‐charge combination uniquely in order to directly probe the effect of these variables on the transport properties of the
particles. Here we present our methods for fabrication, extraction, and analysis of the DNA nano‐ and microparticle tracers, along with results from several successful applications of the tracers, including transport and retention analysis at the lab, continuum, and field scales. Our DNA‐labelled nano‐ and microparticle tracers have proved useful in surface and subsurface water applications, soil retention, and even subglacial flow pathways. The range of potential applications continues to prove nearly limitless.
Helen E. Dahlke, Ph.D., is an Associate Professor in Integrated Hydrologic Sciences at the Department of Land, Air and Water Resources, University of California, Davis. Her research focuses on contributing to a better mechanistic understanding of hydrological processes and their links to climate and biogeochemical cycling. She holds a Masters degree in Geography, Geohydrology and Geoinformatics and a PhD in Environmental Engineering from Cornell University. Helen’s current research interests include surface water – groundwater interaction, water resources management, vadose zone transport processes, hydrologic response functions and applications of DNA nanotechnology in hydrology.
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