Dual signal amplification sensor based on imprint-modified DNA for high-sensitivity detection of copper ions

In order to improve the sensitivity of ion imprinted electrochemical (IIE) sensor to detect copper ions, a novel dual signal amplification (DSA) sensor was proposed using deoxyribonucleic acid (DNA) modified IIE sensor. Chitosan (CS) was used as a functional monomer for IIE sensor. The IIE sensor was prepared by mixing copper ion templates with CS and removing the templates. Gold nanoparticles (AuNPs) were electrodeposited onto the surface of IIE sensor to improve their conductivity and provide a connecting platform for DNA probes. And then the DNA probe was fixed on the surface of AuNPs to prepare a DSA sensor. The signal of DSA sensor was significantly amplified by the synergistic effect of IIE sensor and DNA probe. The feasibility, parameter optimization and electrochemical performance were analyzed by experimental comparison, surface micro scanning and kinetic study. The results show that compared with IIE sensor, the sensitivity of DSA sensor is significantly improved, with a value of 1.6712 x 10-6 A center dot(mu M)-1. The exchange current density is 5.9765 x 10-8 A center dot cm- 2. The detection range is 10 nM to 100 nM (R2 = 0.99651) with the detection limit of 4.17 nM (3 sigma/slope). The recommended method has high sensitivity and selectivity, as well as very high recovery rates in tap water and milk.