One-Step, Room Temperature, Colorimetric Detection of Mercury (Hg²⁺) Using DNA/Nanoparticle Conjugates

Abstract

Introduction of Hg2+ into an aqueous solution containing oligonucleotide-tethered gold nanoparticle probes and a linker oligonucleotide with a number of thymine−thymine (T−T) mismatches results in the formation of particle aggregates at room temperature with a concomitant colorimetric response. The high selectivity of this detection system is attributed to Hg2+-mediated formation of T−Hg2+−T base pairs as evidenced by an increase in a sharp melting temperature.

Rapid colorimetric detection of Hg2+ ion by green silver nanoparticles synthesized using Dahlia pinnata leaf extract

“…Exposure to this heavy metal at even very low concentration (~1 μm/ml) may cause digestive disorders [26], kidney dysfunction [27] and various neurological disorders as well [28,29]. The sensors now available for detecting Hg 2+ are either based on organic compounds [30] and fluorophores [31] or functionalized nanorods [32]. However, the biosynthesized silver nanoparticles were rarely tested for their ability to detect Hg 2+ ions.…”

Immobilization of DNA on Magnetic Microparticles for Mercury Enrichment and Detection with Flow Cytometry

“…[18] While thymine binding to mercury has been known for a long time, [19,20] this study was the first attempt to use a thymine-rich DNA for mercury detection. Since then, this DNA-based mercury recognition mechanism has been used to design many fluorescent, [16,17,[21][22][23][24][25] colorimetric, [11,[26][27][28][29][30][31][32][33][34][35] and electrochemical sensors. [36] Currently, detection limits in the low nanomolar range can be reached.…”

Recent developments on nanomaterials-based optical sensors for Hg2+ detection

“…The Hg 2+ concentration was detected by monitoring the change in the solution color at the T m of the DNA-Au NP aggregates. To avoid heating and develop a convenient system that can work at room temperature, Liu's group [31] improved this strategy through optimizing the DNA sequences and introducing an appropriate oligonucleotide linker. Another simple method based on the interparticle crosslinking aggregation mechanism is carried out by using Au NPs modified with thiolates such as 11-mercaptoun- …”