Electrochemical lead(II) biosensor by using an ion-dependent split DNAzyme and a template-free DNA extension reaction fo
- PDF / 1,176,318 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 30 Downloads / 147 Views
ORIGINAL PAPER
Electrochemical lead(II) biosensor by using an ion-dependent split DNAzyme and a template-free DNA extension reaction for signal amplification Li Zhang 1 & Hanmei Deng 1 & Ruo Yuan 1 & Yali Yuan 1 Received: 12 May 2019 / Accepted: 19 September 2019 # Springer-Verlag GmbH Austria, part of Springer Nature 2019
Abstract A voltammetric biosensor for lead(II) (Pb2+) is described that is based on signal amplification by using an ion-dependent split DNAzyme and template-free DNA extension reaction. The Pb2+-dependent split DNAzyme was assembled on gold nanoparticles (Au@Fe3O4), and this nanoprobe then was exposed to Pb2+ which causes the split-off of DNAzymes to release primers containing 3′-OH groups (S1 and S2). The template-free DNA extension reaction triggers the generation of long ssDNA nanotails, which then can bind the free redox probe N,N′-bis(2-(trimethylammonium iodide)propylene)perylene-3,4,9,10tetracarboxyldiimide (PDA+) via electrostatic adsorption. Hence, the concentration of PDA+ in solution is reduced. Therefore, less free PDA+ can be immobilized on a glassy carbon electrode modified with electrodeposited gold nanoparticles (depAu) to produce an electrochemical signal, typically measured at ∼0.38 V (vs. SCE) for quantitation of Pb2+. The use of a Pb2+-dependent split DNAzyme avoids the usage of a proteinic enzyme. It also increases the sensitivity of the sensor which has a lower detection limit of 30 pM of Pb2+. Keywords Long ssDNA nanotails . Electrostatic adsorption . Sensitive detection . Electrochemical biosensor
Introduction Lead ions (Pb2+) are a common environmental pollutant accompanied by severe human health risks [1–3]. It was demonstrated that Pb2+ can react with the sulfhydryl groups of enzymes. It also can become a substitute of essential metal ions such as iron(III), calcium(II) and zinc(II). This can cause acute and chronic illnesses including colic-like abdominal pains and nephropathy [4]. According to the standard of U.S. environmental Protection Agency (EPA) and World Health Organization (WHO), the maximum acceptable amount of lead in drinking water are 50 μg/L and 10 μg/L, respectively [5, 6]. It is therefore of great importance to explore new approaches to achieve the ultrasensitive detection of Pb2+.
* Yali Yuan [email protected] 1
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People’s Republic of China
Recently emerging Pb2+-dependent split DNAzyme, a DNA nanostructure composed by a catalytic DNA strand (Cat) and a ribonucleobase-containing substrate DNA strand (Sub) [7], can be specially cleaved by Pb2+ with high cleavage activity for releasing massive small DNA segments and thus provide a possibility for its application in the on-site Pb2+ analysis. Based on this, many biosensors with the usage of different detection techniques, including surface-enhanced raman scattering (SERS) [8, 9], fluorescence [10], colorimetry [11], electroche
Data Loading...
