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Open AccessArticle

DNAzyme Sensor for the Detection of Ca2+ Using Resistive Pulse Sensing

Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
Author to whom correspondence should be addressed.
Sensors 2020, 20(20), 5877;
Received: 24 August 2020 / Revised: 7 October 2020 / Accepted: 10 October 2020 / Published: 17 October 2020
(This article belongs to the Section Chemical Sensors)
DNAzymes are DNA oligonucleotides that can undergo a specific chemical reaction in the presence of a cofactor. Ribonucleases are a specific form of DNAzymes where a tertiary structure undergoes cleavage at a single ribonuclease site. The cleavage is highly specificity to co-factors, which makes them excellent sensor recognition elements. Monitoring the change in structure upon cleavage has given rise to many sensing strategies; here we present a simple and rapid method of following the reaction using resistive pulse sensors, RPS. To demonstrate this methodology, we present a sensor for Ca2+ ions in solution. A nanoparticle was functionalised with a Ca2+ DNAzyme, and it was possible to follow the cleavage and rearrangement of the DNA as the particles translocate the RPS. The binding of Ca2+ caused a conformation change in the DNAzyme, which was monitored as a change in translocation speed. A 30 min assay produced a linear response for Ca2+ between 1–9 μm, and extending the incubation time to 60 min allowed for a concentration as low as 0.3 μm. We demonstrate that the signal is specific to Ca2+ in the presence of other metal ions, and we can quantify Ca2+ in tap and pond water samples. View Full-Text
Keywords: DNAzyme; aptamer; nanopore; resistive pulse sensor; metal ion sensor DNAzyme; aptamer; nanopore; resistive pulse sensor; metal ion sensor
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MDPI and ACS Style

Heaton, I.; Platt, M. DNAzyme Sensor for the Detection of Ca2+ Using Resistive Pulse Sensing. Sensors 2020, 20, 5877.

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