High Speed DNA-based Motors for Chemical Sensing

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This project is funded by the Chemical Measurement and Imaging (CMI) Program of the Division of Chemistry at the National Science Foundation. Professor Khalid Salaita of Emory University is developing a new approach for chemical sensing that is based on detecting the motion of DNA-based motors. Chemical sensing is broadly important for fields ranging from point of care diagnostics to agriculture and environmental sustainability. Sensing in biological systems typically occurs in conditions that are far-from-equilibrium, yet most chemical assays are performed at or near equilibrium conditions. Given the extraordinary sensitivity of biological sensing, it is desirable to consider approaches to sensing under conditions that are far-from-equilibrium. There are inherent challenges in pursuing well-controlled reactions that operate out of equilibrium and that can be harnessed for sophisticated chemical measurements. The funded project addresses these challenges and potentially improves current approaches in analytical chemistry. The broader impacts include educational and outreach goals focused on developing new undergraduate and graduate courses that use 3D printing as a tool for the chemical sciences. The course is tailored toward first-year graduate students and undergraduates and enhances their ability to leverage 3D printing in their own research efforts.Professor Salaita's laboratory has examined a new class of synthetic DNA-based motors that move at a speed that is 1000 times faster than current DNA based machines. These motors transport 5-micron particles distances of up to one millimeter. Because the mechanism of motor transport depends on a multistep reaction that involves Watson-Crick base-pairing and catalytic hydrolysis of RNA, the speed of the motor can be used as a reporter of analyte concentration. This assay is optimized for DNA sensing using automated image analysis. The focus is on testing the specificity of the assay by measuring particle speed in response to single nucleotide polymorphism of the target oligonucleotide. The work investigates functional oligonucleotides, thus expanding the scope of motion-based sensing to detect heavy metals and small molecule analytes.