Incorporation of a DNAzyme into Au-coated nanocapillary array membranes with an internal standard for Pb(II) sensing

A Pb(ii)-specific DNAzyme has been successfully incorporated into Au-coated polycarbonate track-etched (PCTE) nanocapillary array membranes (NCAMs) by thiol-gold immobilization. Incorporation of the DNAzyme into the membrane provides a substrate-bound sensor using a novel internal control methodolog...

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Bibliographic Details
Published in:Analyst (London) 2006-01, Vol.131 (1), p.41-47
Main Authors: WERNETTE, Daryl P, SWEARINGEN, Carla B, CROPEK, Donald M, YI LU, SWEEDLER, Jonathan V, BOHN, Paul W
Format: Article
Language:English
Subjects:
Analytical chemistry
Biosensing Techniques - methods
Chemistry
DNA, Catalytic
Environmental Monitoring - methods
Exact sciences and technology
General, instrumentation
Gold
Lead - analysis
Nanostructures - chemistry
Nanotechnology - methods
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Summary:A Pb(ii)-specific DNAzyme has been successfully incorporated into Au-coated polycarbonate track-etched (PCTE) nanocapillary array membranes (NCAMs) by thiol-gold immobilization. Incorporation of the DNAzyme into the membrane provides a substrate-bound sensor using a novel internal control methodology for fluorescence-based detection of Pb(ii). A non-cleavable substrate strand, identical to the cleavable DNAzyme substrate strand except the RNA-base is replaced by the corresponding DNA-base, is used for ratiometric comparison of intensities. The cleavable substrate strand is labeled with fluorescein, and the non-cleavable strand is labeled with a red fluorophore (Cy5 or Alexa 546) for detection after release from the membrane surface. This internal standard based ratiometric method allows for real-time monitoring of Pb(ii)-induced cleavage, as well as standardizing variations in substrate size, solution detection volume, and monolayer density. The result is a Pb(ii)-sensing structure that can be stored in a prepared state for 30 days, regenerated after reaction, and detect Pb(ii) concentrations as low as 17 nM (3.5 ppb).
ISSN:0003-2654
1364-5528
DOI:10.1039/b510071b