CHAMPAIGN, Ill. Researchers at the University of Illinois at Urbana-Champaign have developed a simple, disposable sensor for detecting hazardous uranium ions, with sensitivity that rivals the performance of much more sophisticated laboratory instruments.
The sensor provides a fast, on-site test for assessing uranium contamination in the environment, and the effectiveness of remediation strategies, said Yi Lu, a chemistry professor at Illinois and senior author of a paper accepted for publication in the Proceedings of the National Academy of Sciences, and posted on its Web site.
A unique feature of our uranium sensor is that it contains a small piece of DNA, the same basic building blocks of our genes, said Lu, who also is a researcher at the universitys Beckman Institute for Advanced Science and Technology, and at the Center of Advanced Materials for the Purification of Water with Systems. Our sensor combines the high metal ion selectivity of catalytic DNA with the high sensitivity of fluorescence detection.
While most DNA is double stranded, the catalytic DNA Lus research group uses has a single strand region that can wrap around like a protein. In that single strand, the researchers fashion a specific binding site a kind of pocket that can only accommodate the metal ion of choice.
In this case, the researchers chose to detect uranyl, the most soluble species of uranium ion and the one that poses the greatest threat to human life.
To search for the unique sequence of DNA that could distinguish uranyl from other metal ions, the researchers used a combinatorial approach called in vitro selection. Simple and cost-effective, the selection process can sample a very large pool of DNA (up to 1,000 trillion molecules), amplify the desired sequence by the polymerase chain reaction, and introduce mutations to improve performance.
Lu, with collaborators at Illinois, the Construction Engineering Research Laboratory, Oregon S
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Contact: James E. Kloeppel, Physical Sciences Editor
kloeppel@uiuc.edu
217-244-1073
University of Illinois at Urbana-Champaign
14-Feb-2007