In Vitro Selection of Chromium-Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)
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.
Cite this version of the work
Wenhu Zhou, Mahsa Vazin, Tianmeng Yu, Jinsong Ding, Juewen Liu
(2016).
In Vitro Selection of Chromium-Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI). UWSpace.
http://hdl.handle.net/10012/11782
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