A simple label-free electrochemical aptamer sensor for detection of Hg²⁺ based on black phosphorus

Abstract

In this work, a simple label-free aptamer-based electrochemical sensor was developed for determination of mercury ions (Hg 2+ ) by polylysine (PLL) modified black phosphorus nanosheets (BP) and gold nanoparticles (AuNPs) as signal amplification strategy. The PLL-BP composite materials greatly improved electron transfer speed and electrochemical behavior of electrode in the detection of analytes. AuNPs can amplify the electrochemical signal and facilitate the binding of aptamers to the electrode. The selected aptamer (Apt) can bind specifically to Hg 2+ to form a T-Hg 2+ -T structure, which we used to detect Hg 2+ . Experimental results showed that the prepared electrochemical aptamer sensor exhibited wide linear range from 1.0–500 nM, along with a low detection limit of 0.14 nM. Moreover, the electrochemical aptamer sensor has good specificity, stability, and repeatability. Therefore, this proposed electrochemical aptamer sensor provide a simple and sensitive method for the detection of Hg 2+ , which is expected to be used for the detection of trace amounts of Hg 2+ in actual samples.