Highly Sensitive and Selective Colorimetric Detection of Methylmercury Based on DNA Functionalized Gold Nanoparticles

Abstract

A new colorimetric detection of methylmercury (CH3Hg+) was developed, which was based on the surface deposition of Hg enhancing the catalytic activity of gold nanoparticles (AuNPs). The AuNPs were functionalized with a specific DNA strand (HT7) recognizing CH3Hg+, which was used to capture and separate CH3Hg+ by centrifugation. It was found that the CH3Hg+ reduction resulted in the deposition of Hg onto the surface of AuNPs. As a result, the catalytic activity of the AuNPs toward the chromogenic reaction of 3,3,5,5-tetramethylbenzidine (TMB)-H2O2 was remarkably enhanced. Under optimal conditions, a limit of detection of 5.0 nM was obtained for CH3Hg+ with a linear range of 10–200 nM. We demonstrated that the colorimetric method was fairly simple with a low cost and can be conveniently applied to CH3Hg+ detection in environmental samples.

DNA–Gold Nanozyme-Modified Paper Device for Enhanced Colorimetric Detection of Mercury Ions

“…The DNA–AuNP complex were prepared according to our previous reports [ 17 , 41 ]. To each detection zone on paper chip, 2 μL of the DNA–AuNPs (0.6 nM) was added.…”

DNA-Based Gold Nanoparticle Assemblies: From Structure Constructions to Sensing Applications

“…Colorimetric sensors use color changes as the analysis basis and achieve the qualitative or quantitative detection of target objects by observing and analyzing the color changes caused by the aggregation or dispersion of Au NPs directly or indirectly triggered by the target objects [120]. With the advantages of simple operation, a low price and an intuitive nature, they have been widely used in the fields of environmental pollution, biochemical analysis and disease diagnosis, but the sensitivity is relatively low.…”

A rapid and ultrasensitive colorimetric biosensor based on aptamer functionalized Au nanoparticles for detection of saxitoxin

“…15 The colorimetric sensor based on Au NPs has the advantages of high sensitivity and simplicity, and is capable of realizing real-time detection without large-scale instruments and equipment. It has been used to detect proteins, [16][17][18] DNAs, [19][20][21] metal ions, 22,23 and small molecules. [24][25][26][27] To construct Au NPs based colorimetric sensor, a specic molecule is needed to bind with Au NPs, which can specically react with target molecules, and then gets desorbed from Au NPs resulting in the aggregation of Au NPs to induce color change.…”