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 μM 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 (μA) = 2.59902 + 0.2097logC (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.