Homogeneous biorecognition reaction-induced assembly of DNA nanostructures for ultrasensitive electrochemical detection of kanamycin antibiotic

By the employment of a homogeneous biorecognition reaction to induce the assembled formation of DNA nanostructures at an electrode, herein we develop a novel biosensing method for the ultrasensitive electrochemical detection of kanamycin (Kana) antibiotic. A DNA complex consisting of Kana-aptamer and a hairpin DNA with an exposed 3'-end was first designed for conducting the homogeneous reaction with Kana in the presence of exonuclease I (Exo I). It resulted in the production of a hairpin DNA with a blunt terminus, which could be used for triggering the assembled formation of a layer of DNA nanostructures with orderly distribution and abundant biotin sites at a gold electrode. Then, high-content methylene blue and horseradish peroxidase (HRP)-functionalized gold nanotags would be captured onto the electrode to realize the electrocatalytic signal transduction. Due to the Exo I and HRP-assisted dual signal amplification, a very low detection limit of 9.1 fg mL(-1) was obtained for the Kana assay along with a very wide linear range over five-order of magnitude. Considering the excellent performance of the method, it exhibits a promising prospect for practical applications. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A novel biosensing method for ultrasensitive electrochemical detection of kanamycin antibiotic was developed by inducing the assembled formation of DNA nanostructures at an electrode. Dual signal amplification assisted by Exo I and HRP led to a very low detection limit of 9.1 fg mL(-1) for Kana assay.