title: Incorporation of a DNAzyme into Au-coated nanocapillary array membranes with an internal standard for Pb(ii) sensing.
abstract: 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).
authors.affiliation: Beckman Institute for Advanced Science and Technology and Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801, USA.
authors.forename: Daryl P
authors.initials: DP
authors.lastname: Wernette
authors.forename: Carla B
authors.initials: CB
authors.lastname: Swearingen
authors.forename: Donald M
authors.initials: DM
authors.lastname: Cropek
authors.forename: Yi
authors.initials: Y
authors.lastname: Lu
authors.forename: Jonathan V
authors.initials: JV
authors.lastname: Sweedler
authors.forename: Paul W
authors.initials: PW
authors.lastname: Bohn
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic; D004784:Environmental Monitoring / Q000379:methods*; D006046:Gold; D007854:Lead / Q000032:analysis*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods
chemical_list: D021881:DNA, Catalytic; D007854:Lead; D006046:Gold