Label-free aptamer-based colorimetric detection of mercury ions in aqueous media using unmodified gold nanoparticles as colorimetric probe

Abstract

We report a simple and sensitive aptamer-based colorimetric detection of mercury ions (Hg(2+)) using unmodified gold nanoparticles as colorimetric probe. It is based on the fact that bare gold nanoparticles interact differently with short single-strand DNA and double-stranded DNA. The anti-Hg(2+) aptamer is rich in thymine (T) and readily forms T-Hg(2+)-T configuration in the presence of Hg(2+). By measuring color change or adsorption ratio, the bare gold nanoparticles can effectively differentiate the Hg(2+)-induced conformational change of the aptamer in the presence of a given salt with high concentration. The assay shows a linear response toward Hg(2+) concentration through a five-decade range of 1 x 10(-4) mol L(-1) to 1 x 10(-9) mol L(-1). Even with the naked eye, we could identify micromolar Hg(2+) concentrations within minutes. By using the spectrometric method, the detection limit was improved to the nanomolar range (0.6 nM). The assay shows excellent selectivity for Hg(2+) over other metal cations including K(+), Ba(2+), Ni(2+), Pb(2+), Cu(2+), Cd(2+), Mg(2+), Ca(2+), Zn(2+), Al(3+), and Fe(3+). The major advantages of this Hg(2+) assay are its water-solubility, simplicity, low cost, visual colorimetry, and high sensitivity. This method provides a potentially useful tool for the Hg(2+) detection.

Adsorption of DNA onto gold nanoparticles and graphene oxide: surface science and applications

“…[142][143][144][145] DNA aptamer conformational change induced by target analytes has also been extensively tested with AuNPs and an example for K + detection is shown in Figure 9E. [146][147][148][149][150][151] This method is popular because of its high sensitivity for visual detection and it allows for label-free detection. However, this method is also susceptible to false results.…”

Gravimetric Viral Diagnostics: QCM Based Biosensors for Early Detection of Viruses

“…They are particularly attractive for sensor applications since they are relatively easily to produce with selectivity for a wide variety of analytes. These range from ions [122,123] or small molecules [124] to a wide range of proteins [125] or even entire cells [126,127]. As a result, aptamers Kleo et al [108] fabricated a DNA-QCM biosensor for indirect determination of vaccinia virus DNA using polymerase chain reaction (PCR) amplification.…”

“…They are particularly attractive for sensor applications since they are relatively easily to produce with selectivity for a wide variety of analytes. These range from ions [122,123] or small molecules [124] to a wide range of proteins [125] or even entire cells [126,127]. As a result, aptamers can be used for detecting viruses directly as well as molecules produced by the affected host in response to the viral infection (as for instance antibodies or certain molecules produced on the host cell surface [128]).…”

High Specific DNAzyme-Aptamer Sensor for Salmonella paratyphi A Using Single-Walled Nanotubes–Based Dual Fluorescence-Spectrophotometric Methods

“…[7][8][9][10][11] They have been used to detect pathogenic bacteria, treat cancer, and identify biomarkers. [12][13][14] They have also been tested as a 528538J BXXXX10.1177/1087057114528538Journal of Biomolecular ScreeningNing et al…”