A label-free impedance-based electrochemical sensor based on self-assembled dendritic DNA nanostructures for Pb2+detection

Here, a label-free impedance-based electrochemical sensor was developed for the quantitative detection of Pb2+. Using conductive gold nanomaterials as electrode substrate materials can provide sensors with larger specific surface area, action sites and excellent conductivity. DNA nanostructures are used for the determination of biomolecules due to their good properties. The Y-DNA structure is formed by the annealing of three DNA se-quences, which acts as a stable structure and forms a dendritic structure in combination with the hybrid chain reaction. In the presence of the target Pb2+, it induces the conversion of specific aptamers into G-quadruplexes, resulting in HCR and Y-DNA loading on the electrodes and a significant change in the impedance value signal. Therefore, the proposed biosensor realizes the quantitative detection of Pb2+. Under the optimal experimental conditions, the concentration of Pb2+ exhibited a linear correlation range from 0.5 to1000 nmol/L with a limit of detection (LOD) of 0.38 nmol/L. The designed sensors have good recoveries in real samples (tap water and tea). This flexible experimental protocol has broad application prospects.

Automated summary

This study developed a label-free impedance-based electrochemical sensor for the quantitative detection of Pb2+. The use of conductive gold nanomaterials as electrode substrate materials provides sensors with a larger specific surface area, action sites, and excellent conductivity. DNA nanostructures were utilized for biomolecule determination, leading to successful quantitative detection of Pb2+. The designed sensors demonstrated good recoveries in real samples, making it highly applicable in various fields.