Aptamer-Based Electrochemical Biosensor for Mercury Ions Detection Using AuNPs-Modified Glass Carbon Electrode.

A mercury ion aptamer electrochemical biosensor based on a Thymine-Hg2+ -Thymine (T-Hg2+ -T) structure has been constructed and successfully used to detect mercury ions in tap water samples. The aptamer electrochemical biosensor was assembled using a mercury ion aptamer-functionalized AuNPs-modified glass carbon electrode (aptamer/(AuNPs/CS)₂/GCE) capable of specifically detecting mercury ions through a T-Hg2+ -T structure. The experimental results indicated the optimum electrochemical performance of the prepared aptamer biosensor when the (AuNPs/CS)₂/GCE surface was modified with 1.0 μ M aptamer and incubated with Hg2+ for 60 min. Moreover, the aptamer biosensor exhibits a good linear relationship between the logarithm of the Hg2+ concentration and the DPV peak current in the range from 0.01 to 500 nM following the linearization equation Ip ( μ A) = 2.59902 + 0.2097log C ( R ² = 0.9994) with a limit of detection as low as 0.005 nM. Therefore, the constructed aptamer biosensor provides a simple and sensitive approach for Hg2+ detection in aqueous solution with promising application for trace Hg2+ detection in real samples.