Miniaturized lead sensor based on lead-specific DNAzyme in a nanocapillary interconnected microfluidic device
| Autor: | Paul W. Bohn, Jonathan V. Sweedler, Won-Suk Kim, Juewen Liu, Donald M. Cannon, Yi Lu, Donald M. Cropek, Joseph J. Tulock, In-Hyoung Chang |
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| Rok vydání: | 2005 |
| Předmět: |
Fluorophore
Microfluidics Deoxyribozyme Analytical chemistry Industrial Waste Biosensing Techniques chemistry.chemical_compound Molecular beacon Environmental Chemistry Electroplating Detection limit Sewage business.industry Chemistry General Chemistry DNA Catalytic Equipment Design Fluorescence Nanostructures Membrane Lead Optoelectronics business Water Pollutants Chemical Environmental Monitoring |
| Zdroj: | Environmental sciencetechnology. 39(10) |
| ISSN: | 0013-936X |
| Popis: | A miniaturized lead sensor has been developed by combining a lead-specific DNAzyme with a microfabricated device containing a network of microfluidic channels that are fluidically coupled via a nanocapillary array interconnect. A DNAzyme construct, selective for cleavage in the presence of Pb2+ and derivatized with fluorophore (quencher) at the 5' (3') end of the substrate and enzyme strands, respectively, forms a molecular beacon that is used as the recognition element. The nanocapillary array membrane interconnect is used to manipulate fluid flows and deliver the small-volume sample to the beacon in a spatially confined detection window where the DNAzyme is interrogated using laser-induced fluorescence detection. A transformed log plot of the fluorescent signal exhibits a linear response (r2 = 0.982) over a Pb2+ concentration range of 0.1 - 100 microM, and a detection limit of 11 nM. The sensor has been applied to the determination of Pb2+ in an electroplating sludge reference material, the result agreeing with the certified value within 4.9%. Quantitative measurement of Pb2+ in this complex sample demonstrates the selectivity of this sensor scheme and points favorably to the application of such technologies to analysis of environmental samples. The unique combination of a DNAzyme with a microfluidic-nanofluidic hybrid device makes it possible to change the DNAzyme to select for other compounds of interest, and to incorporate multiple sensing systems within a single device for greater flexibility. This work represents the initial steps toward creation of a robust field sensor for lead in groundwater or drinking water. |
| Databáze: | OpenAIRE |
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