Fabrication of a Label‐free Femtomolar Electrochemical Mercury Ion Biosensor Based on Oligonucleotide Receptor Layers Hybridized with Multi‐walled Carbon Nanotubes

Abstract

The feasibility of designing a highly selective and sensitive label-free cost-effective biosensor to determine Hg 2 + ions using gold electrodes functionalized with short-chain, thymine-rich, ss-DNA oligonucleotides wrapped MWNTs is examined. The potassium ferricyanide was used as a redox marker for analytical signal generation. Biosensor response was based on the differ-ence in the electrochemical signal before and after subjecting it to a sample containing Hg 2 + ions. The lowest detection limit of 1 femtomolar (fM) of mercury ions was observed in the aqueous medium, together with good selectivity against common metal cations. The method developed was successfully applied for the determination of Hg 2 + ions in environmental waste water samples.

Boron-Doped Diamond Modified with 4-Mercaptopyridine-Functionalized Gold Nanoparticles for Trace Mercury Detection

“…Wang’s group reported a device based on gold-modified thiol graphene to detect trace Hg 2+ . Pal et al developed a sensor for Hg 2+ detection using gold electrodes functionalized with thymine-rich, ss-DNA oligonucleotide-wrapped carbon nanotubes . Promising results have been achieved by these methods, but complicated fabrication processes and complex biochemical reagents are commonly required, which limits their practical application for on-site detection.…”