In Vitro Selection of Chromium-Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)
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Date
2016-07-04
Authors
Zhou, Wenhu
Vazin, Mahsa
Yu, Tianmeng
Ding, Jinsong
Liu, Juewen
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Chromium is a very important analyte for environmental monitoring, and developing biosensors for chromium is a long-standing analytical challenge. In this work, in vitro selection of RNA-cleaving DNAzymes was carried out in the presence of Cr3+. The most active DNAzyme turned out to be the previously reported lanthanide-dependent Ce13d DNAzyme. Although the Ce13d activity was about 150-fold lower with Cr3+ than that with lanthanides, the activity of lanthanides and other competing metals was masked by using a phosphate buffer; this left Cr3+ as the only metal that could activate Ce13d. With 100 mu mm Cr3+, the cleavage rate is 1.6 h(-1) at pH 6. By using a molecular beacon design, Cr3+ was measured with a detection limit of 70 nm, which was significantly lower than the United States Environmental Protection Agency (EPA) limit (11 mu m). Cr4+ was measured after reduction by NaBH4 to Cr3+, and it could be sensed with a similar detection limit of 140 nm Cr4+; this value was lower than the EPA limit of 300 nm. This sensor was tested for chromium speciation analysis in a real sample, and the results supported its application for environmental monitoring. At the same time, it has enhanced our understanding of the interactions between chromium and DNA.
Description
This is the peer reviewed version of the following article: Zhou, W., Vazin, M., Yu, T., Ding, J., & Liu, J. (2016). In Vitro Selection of Chromium-Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI). Chemistry-a European Journal, 22(28), 9835–9840, which has been published in final form at https://doi.org/10.1002/chem.201601426. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Keywords
Rna-Cleaving DNAzyme, Electrochemical Detection, Metal-Ions, DNA, Speciation, Sensor, Biosensor, Cleavage, Water, Preconcentration