Electrochemical Biosensor Using DNA Embedded Phosphorothioate Modified RNA for Mercury Ion Determination

Abstract

Mercury (Hg) and its compounds, originating from a variety of natural and anthropogenic sources, are ubiquitous in the natural environment, and cause severe environmental contamination and pose irreversible harm to human health. A fast and accurate sensing approach is of significant importance for mercury detection. Here, a label-free biosensor using Hg(II)-induced cleavage of phosphorothioate (PS) modified RNA was exploited. We designed a specific single-stranded DNA embedded with four PS-modified RNA (Hg-DPR) to improve the cleavage reaction yield, and then Hg-DPR was covalently linked with single-walled carbon nanotube field effect transistor (SWNTs/FET) via a peptide bond. The Hg-DPR can be efficiently cleaved after exposure to Hg(II), which further causes the conductivity of the SWNTs to change. Using the relative resistance change, the Hg-DPR/SWNTs/FET successfully detected Hg(II) levels as low as 10 pM, and the calibration curves were linear in the range of 50 pM to 100 nM and 100 nM to 10 μM. Additionally, Hg-DPR/SWNTs/FET exhibited excellent sensitivity, portability, and low-cost for Hg(II) detection.

Single‐gap Microelectrode Functionalized with Single‐walled Carbon Nanotubes and Pbzyme for the Determination of Pb2+

“…When FET was functionalized with SWNTs, the morphology of SWNTs/FET was tested using a scanning electron microscope and shown in Figure (C). SWNTs were uniformly distributed on the area between the source and drain, which indicated that SWNTs bond with SiO 2 very well .…”

“…Table shows the performance parameters of the reported electrochemical sensors, such as the linear range, limit of detection and detection time. Compared to other sensors , the detecting parameters of Pbzyme/SWNTs/FET were beyond most electrochemical sensors, except DNA/SWNTs/FET. DNA/SWNTs/FET for Pb 2+ determination had a wide linear rang and lower limit of detection of were much better, but the detection time reached 20 min, which was not suitable to rapid detection in site.…”

Bioelectronic Nose Based on Single-Stranded DNA and Single-Walled Carbon Nanotube to Identify a Major Plant Volatile Organic Compound (p-Ethylphenol) Released by Phytophthora Cactorum Infected Strawberries

“…Owing to the excellent electrical, optical, and mechanical properties, carbon materials, including fullerene, carbon black, carbon nanofiber, carbon nanotubes, and graphene, are ideal materials for developing the new generation of miniaturized, low-power, ubiquitous electronic or bioelectronic noses [5][6][7]. As one type of carbon nanotube, single-walled carbon nanotube (SWNT) is a one-atom-thick layer of graphite rolled up into a seamless cylinder with a diameter of several nanometers, and length on the order of 1-100 microns [8], which offers a high specific surface area to enhance the sensitivity. Based on electrical conductivity, there are two different types: semiconducting SWNT and metallic SWNT.…”

One‐step Green Synthetic Approach for the Preparation of Orange Light Emitting Copper Nanoclusters for Sensitive Detection of Mercury(II) Ions

“…In addition, the strong interaction between Hg 2+ and the thiol groups of proteins and enzymes can cause abnormal body function in various vital organs of the human body. Thence, the sensitive and selective detection of mercury ions in the environment is very critical …”