Quencher-Free Fluorescence Method for the Detection of Mercury(II) Based on Polymerase-Aided Photoinduced Electron Transfer Strategy.

Haisheng Liu,Linbin Ma,Kemin Wang,Meilan Wang,Changbei Ma,Junyan Du

doi:10.3390/s16111945

Abstract

A new quencher-free Hg2+ ion assay method was developed based on polymerase-assisted photoinduced electron transfer (PIET). In this approach, a probe is designed with a mercury ion recognition sequence (MRS) that is composed of two T-rich functional areas separated by a spacer of random bases at the 3′-end, and a sequence of stacked cytosines at the 5′-end, to which a fluorescein (FAM) is attached. Upon addition of Hg2+ ions into this sensing system, the MRS folds into a hairpin structure at the 3′-end with Hg2+-mediated base pairs. In the presence of DNA polymerase, it will catalyze the extension reaction, resulting in the formation of stacked guanines, which will instantly quench the fluorescence of FAM through PIET. Under optimal conditions, the limit of detection for Hg2+ ions was estimated to be 5 nM which is higher than the US Environmental Protection Agency (EPA) standard limit. In addition, no labeling with a quencher was requiring, and the present method is fairly simple, fast and low cost. It is expected that this cost-effective fluorescence method might hold considerable potential in the detection of Hg2+ ions in real biological and environmental samples.

Highlights

Heavy metals are a serious global problem because of their toxicity to the environment and human health [1,2]
Hg2+ is easy to accumulate in human bodies but hard to biodegrade when it enters the body through food or water [4]
30 -end is a The mercury ionisrecognition (MRS) that is composed that composed of two areas

Summary

Introduction

Heavy metals are a serious global problem because of their toxicity to the environment and human health [1,2]. Mercury(II) (Hg2+ ) is one of the toxic heavy metals on the list of the Agency for Toxic. Substances and Disease Registry (ATSDR) of the US Department of Health and Human Services [3]. Hg2+ is easy to accumulate in human bodies but hard to biodegrade when it enters the body through food or water [4]. According to the US Environmental Protection Agency (EPA) standard, the maximum allowable level for Hg2+. The development of a simple, sensitive, environmentally friendly, yet low-cost method for Hg2+ ions detection is needed [9,10]

Methods

Results

Conclusion