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.
Highlights
The monitoring of lead ions (Pb2+) in the aquatic ecosystem is of great importance due to their harmful effect on the environment and human health [1,2,3]
Conventional methods have been used in the laboratory for detecting trace amounts of Pb2+ include atomic absorption/emission spectrometry, inductively coupled plasma mass spectrometry (ICP-MS) etc. [4,5,6,7]
We developed a regenerative, sensitive and selective electrochemical aptasensor for Pb2+ detection based on electrochemically reduced graphene oxide (ERGO)
Summary
The monitoring of lead ions (Pb2+) in the aquatic ecosystem is of great importance due to their harmful effect on the environment and human health [1,2,3]. Anodic stripping voltammetry (ASV) [8] is conventionally employed to detect Pb2+ which is relatively simple and cost effective compared with other conventional methods still suffers from the low sensitivity for trace analysis. The challenge remains to develop new approaches for Pb2+ detection with high sensitivity, selectivity, cost-effectiveness, and simplicity in order to protect human health and the ecological environment. To meet this objective, many different electrochemical techniques have been proposed and proven to be promising tools for Pb2+ detection due to their high sensitivity, easy operation, rapid analysis, and ease of miniaturization, as well as the low cost of analysis [9,10,11]. We developed a regenerative, sensitive and selective electrochemical aptasensor for Pb2+ detection based on electrochemically reduced graphene oxide (ERGO)
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