Huang, Po-Jung JimmyLiu, Juewen2017-02-272017-02-272014-05-22http://dx.doi.org/10.1021/ac501070ahttp://hdl.handle.net/10012/11367This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see Huang, P.-J. J., & Liu, J. (2014). Sensing Parts-per-Trillion Cd 2+ , Hg 2+ , and Pb 2+ Collectively and Individually Using Phosphorothioate DNAzymes. Analytical Chemistry, 86(12), 5999–6005. https://doi.org/10.1021/ac501070aCadmium, mercury, and lead are collectively banned by many countries and regions in electronic devices due to their extremely high toxicity. To date, no sensing method can detect them as a group and also individually with sufficient sensitivity and selectivity. An RNA-cleaving DNAzyme (Ce13d) was recently reported to be active with trivalent lanthanides, which are hard Lewis acids. In this work, phosphorothioate (PS) modifications were systematically made on Ce13d. A single PS modification at the substrate cleavage site shifts the activity from being dependent on lanthanides to soft thiophilic metals. By incorporating the PS modification to another DNAzyme, a sensor array was prepared to detect each metal. Individual sensors have excellent sensitivity (limit of detection = 4.8 nM Cd2+, 2.0 nM Hg2+, and 0.1 nM Pb2+). This study provides a new route to obtain metal-specific DNAzymes by atomic replacement and also offers important mechanistic insights into metal binding and DNAzyme catalysis.enDNAzymesRNA cleavageMetal ionsArticle