Preparation of a novel DNA-imprinted sensor based on chitosan and its highly sensitive detection of Pb²

Lead ion is very harmful to the environment, so it is very important to study its detection methods. In this study, a novel electrochemical sensor was constructed by modifying deoxyribonucleic acid (DNA) on the electrode, which can be used for the detection of Pb²⁺ in the environment. Part of the mixed solution of chitosan (CS) and Pb²⁺ template ions was dropped onto the surface of a glassy carbon electrode. CS-Pb²⁺ film was cross-linked through sodium tripolyphosphate. And a novel DNA-imprinted sensor was prepared by electrodepositing CS-Pb²⁺ thin film with gold nanoparticles (AuNPs), removing Pb²⁺ templates, and immobilizing specific double-stranded DNA. The electroactive area, surface morphology, sensitivity, and electrochemical reaction mechanism of the DNA-imprinted sensor were analyzed. The elementary reaction steps were studied through electrochemical reaction kinetics analysis. The experimental results indicate that the DNA-imprinted electrochemical biosensor can quantitatively detect Pb²⁺ in the range of 10-100 μM (R² = 0.9935), and its detection limit is 6.5074 μM (3σ/slope). The sensitivity of the electrochemical biosensor is 1.55233 × 10^-6 A/μM, and its active areas is 6.233 cm². The desorption mechanism and adsorption mechanism have been explored through dynamic parameter analysis. The novel DNA imprinted electrochemical biosensor developed in this paper provides a robust method for detecting lead ions in solution. Additionally, it establishes a solid groundwork for detecting other metal ions.