Highly Sensitive Detection of Hg²ᐩ Based on Imprinting Sensor Modified DNA

In order to enhance the sensitivity of the imprinted electrochemical sensor for detecting mercury ions, a novel ionimprinted electrochemical sensor modified with deoxyribonucleic acid (DNA) was proposed. A target imprinted with mercury ions was prepared using gold nanoparticles (AuNPs), mercury ion templates, and chitosan. Subsequently, a sensor imprinted with DNA was prepared by immobilizing DNA probes on the surface of AuNPs. The feasibility, electrochemical performance, and electrochemical reaction mechanism of the DNA-imprinted sensors were analyzed through experimental comparisons, scanning electron microscope (SEM), and kinetic studies. The working curve was obtained by the DPV method. The results show that the DNA-imprinted sensor achieves multiple signal amplifications through the unique coordination between Hg2+ and thymine (T) bases, as well as the formation of strong complexes between Hg2+ and chitosan molecularly imprinted polymers. The sensitivity of the DNA-imprinted sensor is significantly improved to
${2.282} \times {10}^{-{6}}$
A
$\cdot $
(uM)-1. In addition, the exchange current density of the DNA-imprinted sensor is
${5.793} \times {10}^{-{8}}$
A
$\cdot $
cm-2. The detection range was 10–60 nM with the detection limit of 1.62 nM (
${3}\sigma $
/slope). The dynamics of DNA-imprinted sensor were analyzed. The proposed detection method provides theoretical and technical support for the detection application of Hg2+ and other ions.