DNAzyme-driven Cascade DNA Walker Fluorescent Biosensor for Highly Sensitive Detection of Kanamycin

The contamination of marine environments with antibiotics, such as kanamycin, poses a significant ecological threat due to its potential harmful effects on marine organisms. Conventional methods for detecting kanamycin, including high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assays (ELISA), face challenges in terms of cost, complexity, and long detection times. This research aims to address these limitations by developing a novel, highly sensitive biosensing platform for kanamycin detection based on a DNAzyme-driven cascade reaction coupled with nanoparticle technology. The method utilizes aptamers for specific kanamycin recognition, which activates DNAzyme-1, triggering a downstream DNA walker system. This cascade reaction amplifies fluorescence signals, significantly enhancing sensitivity. The optimized platform demonstrated a wide detection range (0.05–3 nmol/L) and a low detection limit of 0.0327 nmol/L. This system showed excellent specificity for kanamycin, even in the presence of other antibiotics, and was successfully applied to detecting kanamycin in seawater samples with high recovery rates (94%–102.9%). This DNAzyme-based biosensor offers a promising approach for rapid, cost-effective, and high-sensitivity monitoring of antibiotic contamination in aquatic environments, with potential applications in environmental monitoring and ecological protection.