Electrochemical Detection of Ultratrace Lead Ion through Attaching and Detaching DNA Aptamer from Electrochemically Reduced Graphene Oxide Electrode

Abstract

This paper describes a simple strategy for the ultratrace level detection of Pb2+ ion based on G-quadruplex DNA and an electrochemically reduced graphene oxide (ERGO) electrode. First, ERGO was formed on a glassy carbon electrode (GCE) by the reduction of graphene oxide (GO) using cyclic voltammetry. Subsequently, a methylene blue (MB)-tagged, guanine-rich DNA aptamer (Apt) was attached to the surface of ERGO via π-π interaction, leading to the Apt-modified ERGO electrode. The presence of Pb2+ could generate the folding of Apt to a G-quadruplex structure. The formation of G-quadruplex resulted in detaching the Apt from the ERGO/GCE, leading to a change in redox current of the MB tag. Electrochemical measurements showed the proposed sensor had an exceptional sensitivity for Pb2+ with a linear range from 10−15 to 10−9 M and a detection limit of 0.51 fM. The sensor also exhibited high selectivity for Pb2+, as well as many other advantages, such as stability, reproducibility, regeneration, as well as simple fabrication and operation processes.

Electrochemical Affinity Biosensors Based on Selected Nanostructures for Food and Environmental Monitoring

“…Regarding nucleic acid-based biosensors, it is remarkable the simple preparation and operation of the aptasensor reported by Yu et al [ 89 ] for the label-free determination of Pb 2+ by attaching via Π-Π interaction a guanine-rich DNA aptamer tagged with methylene blue (MB) to the surface of GCE modified with ERGO ( Figure 6 ). In the presence of the target ion the aptamer was folded to a G-quadruplex structure and detached from the ERGO/GCE, producing a decrease in the reduction peak current of the MB tag recorded by CV and DPV.…”

“… Schematic display of the simple and reusable aptasensor developed for the label-free voltammetric determination of Pb 2+ involving a G-quadruplex DNA and an ERGO-modified GCE; DPV signals recorded for different Pb 2+ concentrations in 10 mM Tris buffer. Reprinted from [ 89 ] with permission. …”

Flexible Screen Printed Aptasensor for Rapid Detection of Furaneol: A Comparison of CNTs and AgNPs Effect on Aptasensor Performance

“…Among different biorecognition elements, aptamers are characterized by different advantages such as low cost, facile synthesis, thermostability, and shelf life [13]. Hence, the aptasensors have become attractive in the bioanalytical field for different reasons: simplicity, high sensitivity, high selectivity, low cost, and fast response [14][15][16], compared to more traditional biorecognition elements like enzymes and antibodies [17]. Aptamers are in vitro-selected single-stranded DNA or RNA that are isolated via an in vitro selection process called 'systematic evolution of ligands by exponential enrichment' (SELEX) [18].…”

“…To increase the sensitivity of the biosensor, usually, the working electrode is functionalized with nanomaterials such as carbon nanotubes (CNTs) and metal-nanoparticles (e.g., gold, platinum, silver, titanium, and iron) [14]. CNTs have attained great interest in electrochemical biosensors due to their high surface area to volume ratio and stability [21], as well as due to their good conductivity.…”

A Novel Ratiometric Electrochemical Biosensor Based on a Split Aptamer for the Detection of Dopamine with Logic Gate Operations

“…Electrochemical aptamer‐based biosensors (E‐AB) have attracted great interest due to their simplicity, robustness, reusability, and low cost, while being also highly sensitive and selective. These sensors have proven to be able to detect a variety of different analytes such as small molecules, proteins, inorganic ions, or even cells . E‐ABs traditionally utilize target‐induced conformational changes as transducer principles to generate a sensor signal.…”