ENVR 183 |
| Highly sensitive and selective colorimetric sensors for trace contaminants in the environment is an important area of research as they allow simple, on-site and real-time detection and quantification without the need of sophisticated equipment. To the goal, we use a combinatorial biology method called in vitro selection to obtain catalytic DNA molecules (DNAzymes) that can bind any metal ion of choice strongly and specifically1-3. By labeling DNAzymes with gold nanoparticles, we have developed sensitive and specific colorimetric sensors for Pb2+ and UO22+ 4,5. Practical applications such as the detection of Pb2+ in leaded paint and dust, below the federal threshold of 1 mg/cm2 (paint) and 40 µg/ft2 (dust) has been demonstrated. Recently we have expanded to a new methodology, called label-free detection which does not require attachment of the gold nanoparticles to the DNA, thus lowering cost for the tests. In addition, this method is faster and has lowered the detection limit for both Pb2+ and UO22+ to 1 nM, which is significantly below the drinking water toxicity level defined by EPA as 75 nM for Pb2+ and 130 nM for UO22+. 1. Jing Li et al. Nucleic Acids Res. 28, 481-488 (2000). 2. Jing Li and Yi Lu, J. Am. Chem. Soc. 122, 10466-10467 (2000). 3. Juewen Liu et al. Proc. Natl. Acad. Sci. 104, 2056-2061 (2007). 4. Juewen Liu and Yi Lu, J. Am. Chem. Soc. 125, 6642-6643 (2003). 5. Juewen Liu and Yi Lu, J. Am. Chem. Soc. 127, 12677-12683 (2005). |
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Sensors for Detection and Quantification of Contaminants in Drinking Water and the Environment
1:30 PM-5:10 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 235, Oral
Division of Environmental Chemistry |