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Updated: Jul 8, 2026
A Method for Selecting Structure-switching Aptamers Applied to a Colorimetric Gold Nanoparticle Assay
Published on: February 28, 2015
Specific colorimetric detection of cyanide triggered by a conformational switch in vitamin B12
1Department of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich, Switzerland. zelder@aci.unizh.ch
Abstract:
"Base on"/"base off" coordination of the intramolecular bound benzimidazole nucleobase of vitamin B 12 allows the specific colorimetric detection of millimolar concentrations of cyanide in water. In various competition experiments, it was demonstrated that up to 12 different anions as well as a 1000-fold excess of Cl (-) over CN (-) do no interfere with the sensor. An 8-fold increased sensitivity in the "naked eye" detection of CN (-) was observed when water was replaced by MeOH/H 2O (5%) as a solvent.
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