A Label-free “Turn-on” Fluorescence Method for Detecting Mercury Ion in Aqueous Solution Based on N-Methyl Mesoporphyrin IX (NMM)/G-quadruplex DNA

Abstract

In the present work, a simple design of "turn-on" fluorescence method for mercury ion was developed and explored based on specific T-Hg-T mismatches as a recognizer and N-methyl mesoporphyrin IX (NMM)/G-quadruplex DNA system as a reporter. The titration experiment showed that the mercury-ion concentration and the fluorescence intensity signal change exhibited a consistent linear correlation within the 50 to 500 nM range with a detection limit down to 12.9 nM. In a selectivity experiment, our method showed obvious selectivity against other metal ions, being consistent with other reported detection methods of mercury ion based on the specific reactivity of T-Hg-T mismatches. Our method was then successfully employed to detect mercury ion in pond water with excellent reliability.

Mercury Sensing Probes

“…Zhang et al used N-methyl mesoporphylin IX (NMM)/G-quadruplex DNA system as reporter. 7 Xiang et al also used molecular beacon and Hoechst 33258 as a reporter, and applied it to the detection of Hg 2+ in soil with a detection limit of 3 nM. 8 Nanomaterials were also successively applied for Hg detection.…”

Rhodol-derived Colorimetric and Fluorescent Probe with the Receptor of Carbonothioate for the Specific Detection of Mercury Ions

“…1,2 Once inorganic mercury ions are introduced into the environment, bacteria can convert them into organic mercury species (such as methyl mercury). [3][4][5] It can easily pass through biological membranes and cause damage to the brain, liver, kidney, immune and central nervous system based on its high affinity to the thiol group in proteins and enzymes. [6][7][8][9][10] Therefore, developing effective and sensitive techniques to selectively detect Hg 2+ is of great significance in the environmental science and biological science.…”

A Label-free and Highly Sensitive Fluorescence Strategy for Mercury Ion Detection Based on Exonuclease III-aided Recycling Amplification

“…33,34 In our previous work, the NMM/G-quadruplex DNA system was used to detect mercury ions. 35 However, the sensitivity is not good enough due to the lack of a cycle amplification process. Exonuclease III (Exo III) is a sequence-independent enzyme that can catalyze the stepwise removal of mononucleotides from 3′-hydroxyl termini of double-stranded DNA.…”