Arsenic Removal from Vietnamese Groundwater Using the Arsenic-Binding DNA Aptamer

Abstract

Single-stranded DNA aptamers were generated from a random library to remove arsenic from Vietnamese groundwater. On the basis of significant arsenic contamination levels, three areas in Ha Nam province (Vinh Tru, Bo De, and Hoa Hau) and five areas near the Mekong River Delta (MR1-5) were selected as study areas. The aptamers were in vitro selected using an arsenic aptamer affinity column created by immobilizing arsenic on Affi-gel 10 resin. Quantitative analyses of the aptamer candidates Ars-1 to Ars-8 by surface plasmon resonance (SPR) revealed the Ars-3 aptamer to have the highest affinity to arsenate [(As(V)] and arsenite [As(III)] with a dissociation constant (K(d)) of 4.95 +/- 0.31 and 7.05 +/- 0.91 nM, respectively. The specific affinity interactions of the Ars-3 aptamer to arsenic were verified against other heavy metals. After obtaining successful removal results with a laboratory-prepared aqueous arsenic solution, Ars-3 was applied for removal of any arsenic present in the groundwater samples collected from the studied areas in Vietnam. Field results were also successful: various arsenic concentrations ranging from 28.1 to 739.2 microg/L were completely removed after 5 min of incubation with the arsenic-binding aptamer Ars-3.

A mini-review on functional nucleic acids-based heavy metal ion detection

“…It should be noticed that although the acronym SELEX was often be applied to describe all selection experiments, strictly speaking it applies only to the selections of aptamers but not to that of nucleic acid enzymes (RNAzymes and DNAzymes) (Li and Lu 2009). Though the SELEX method has been reported since 1990 (Ellington and Szostak 1990;Tuerk and Gold 1990) and claimed able to selected aptamer for almost every desired target (Famulok et al, 2007), until now only four heavy metal ions, such as Zn 2+ (Rajendran and Ellington 2008), Cd 2+ (Wang et al, 2016;Wu et al, 2014b), Pd 2+ (Cho et al, 2015) and As (Kim et al, 2009) have obtained their aptamers through SELEX. The actually binding mechanism of aptamer to its target remains indistinct, but it is widely believed that hydrogen bonds (Fig.…”

A simple and sensitive fluorimetric aptasensor for the ultrasensitive detection of arsenic(III) based on cysteamine stabilized CdTe/ZnS quantum dots aggregation

“…Based on the secondary structure predicted of the aptamer, using Zuker's algorithm, Mfold (Kim et al, 2009) (Fig. 3C), there are many sites in the aptasensor to interact with As(III).…”

Aptamer based electrochemical sensors for emerging environmental pollutants

“…According to official sources, arsenic level in water is exceeded than the allowable limit leading to serve arsenic toxicity among inhabitants. As a result, an aptansensor has been proposed by Kim et al group to detect arsenic, with potential tool to be used as alarming method (Kim et al, 2009). Mercury has also been detected by the combination of gold nanoparticles and aptamer with optical output (Li et al, 2009; Helwa et al, 2012).…”