DNA Sensors for the Detection of Mercury Ions

Abstract

Ecosystem pollution by mercury ions (Hg²⁺) is a major health concern, yet classical analytical methods for mercury analysis are limited. This paper reviews the advances in Hg²⁺ detection using DNA as recognition elements in the sensors. DNA as a recognition molecule is inexpensive, simple, and appropriate for real-time detection of Hg²⁺. This paper discusses the DNA-based sensors that were used for the detection of Hg²⁺. These can be carried out by electrochemistry, field effect transistors (FET), Raman spectroscopy, colorimetry, and fluorescence resonance energy transfer (FRET). The detection principles and the advantages of DNA in these sensors are also revealed. Finally, the paper provides an overview of prospects and potential challenges in the field.

Keywords: DNA-based sensors; detection of Hg2+; methods.

Figure 1

Heavy metal ions detection using electrochemical sensing. The working electrode, reference electrode, and counter electrode are inserted into an electrolytic cell containing a heavy metal. The heavy metal ion platform or receptor at the interface of the working electrode reacts with the heavy metal to produce a changing current signal. The electrochemistry workstation, consisting of three electrodes, receives the signal and transmits it to the computer for analysis and processing. The output signal materializes the data to detect heavy metals directly or indirectly. Working electrode (WE): The interface contains a variety of materials that act as platforms or receptors for heavy metal ions. This improves the sensitivity, selectivity, and stability in heavy metal detection. The reference electrode (RE) is an electrode used as a reference when measuring the potential of various electrodes. The counter electrode (CE) balances the current to ensure that the electrochemical reaction can continue. Reproduced from Ju et al. (2015) with permission of Elsevier [67].

Figure 2

Preparation of gold nanoparticles (AuNPs)/reduced graphene oxide (rGO). SERS: surface-enhanced Raman scattering; DTT: DL-Dithiothreitol. The active substrates of heterojunction SERS and sensing for Hg²⁺. AuNPs were grown on the surface of rGO to form a SERS substrate, and the DNA probe was fixed with a thiol group using an Au-S bond. The detected trace of Hg²⁺ by T-Hg²⁺-T coordination reached the detection limit of 0.1 nM. Reproduced from Liu et al. (2013) with permission from the American Chemical Society [107].