Highly sensitive electrochemical sensor using a MWCNTs/GNPs-modified electrode for lead (II) detection based on Pb²⁺-induced G-rich DNA conformation

Abstract

A sensitive electrochemical lead ion (Pb(2+)) sensor based on carboxylic acid group functionalized multi-walled carbon nanotubes (MWNTs-COOH) and direct electrodeposited gold nanoparticles (GNPs) was developed for Pb(2+) detection. The DNA capture probe was self-assembled onto the surface of the modified electrode for hybridizing with the guanine-rich (G-rich) aptamer probe and for forming the DNA double helix structure. When Pb(2+) was added in, the DNA duplex unwound and formed a stabilized G-quadruplex (G4) due to the Pb(2+)-induced G-rich DNA conformation. Also, methylene blue (MB) was selected as the G4-binding indicator. Compared with previous Pb(2+) sensors, the proposed sensor had better sensitivity, because the modified MWCNTs/GNPs could provide a large surface area and good charge-transport capacity to dramatically improve the DNA attachment quantity and sensor performance. The sensor could detect Pb(2+) in a range from 5.0 × 10(-11) to 1.0 × 10(-14) M, with a detection of 4.3 × 10(-15) M.

Electrochemical Sensor based on Imprinted Sol-Gel Polymer on Au NPs-MWCNTs-CS Modified Electrode for the Determination of Acrylamide

“…Electrochemical sensor has received increasing attention in many fields due to their low cost, small size, fast response time, possibility of achieving low detection limits, and strong operability (Zhu et al 2014;Wang et al 2014a, b). A critical aspect of the sensor development is integration of the recognition element with the transducer .…”

Effects of Functionalized Electrodes and Gold Nanoparticle Carrier Signal Amplification on an Electrochemical DNA Sensing Strategy

“…To ensure the comparability of the four kinds of functionalized electrodes, EAuC‐GCE, EAu‐CNT‐GCE, and Ge‐EAu‐GCE were prepared according to our previous work, in which the preparation conditions were optimized to obtain optimal performance . Because the Au electrodeposition time of 60 s was the optimized result for EAu‐CNT‐GCE and Ge‐EAu‐GCE, an electrodeposition time of 60 s was also used in the preparation of EAu‐GCE to maintain consistency. The optimal Au electrodeposition time for EAuC‐GCE was 120 s because Au was not directly electrodeposited on the GCE, and a track‐etched porous polycarbonate (PC) membrane template existed between the GCE and solution .…”

“…Herein, an electrochemical DNA sensing experiment based on functionalized electrodes and the nanoAu carrier signal amplification strategy was designed to investigate the effects of the two ways on the performance of the sensors (Scheme ). The functionalized working electrodes were prepared to achieve optimal performance by using the optimized process we published previously . A thiolated single‐stranded DNA (P1) was used to self‐assemble onto the nanoAu‐modified electrode surface through thiol–gold bonding .…”

Enhanced performance based on a hybrid cathode backing layer using a biomass derived activated carbon framework for methanol fuel cells

“…the reactivity of electrode is reduced by the presence of the nonconductive particles on electrode surface and the type or the amount of binder has crucial effect on electrode reactivity [35][36][37]. Electrochemical impedance is an efficient technique may use to investigate the electrode/electrolyte parameters [38]. Potassium ferrocyanide of 5mM in 0.5 M H2SO4 has been selected to use as redox prop with potential of zero V vs. Ag/AgCl and frequency range is 0.1-10 5 Hz to evaluate diamond composite electrode.…”