Aptamer-based DNAzyme walker electrochemical biosensing strategy for Acinetobacter baumannii detection

In this study, an innovative electrochemical biosensor was developed for the rapid, specific, and sensitive detection of Acinetobacter baumannii without the need for sample pretreatment. The biosensor utilized an aptamer as a specific capture probe for A. baumannii and employed a self-powered DNAzyme walker cleavage cycle reaction to achieve signal amplification. Upon introduction of the target bacteria, the aptamer captured the bacteria and released the Trigger, activating the DNAzyme to cleave the substrate chain containing methylene blue (MB). This led to the release of MB-labeled DNA fragments from the electrode surface, resulting in a significant decrease in the square wave voltammetry (SWV) signal of MB on the sensing platform. The limit of detection (LOD) for A. baumannii was determined to be 30 CFU/mL, enabling discrimination of the target bacteria from other common clinical isolates. Furthermore, the biosensor’s potential for real sample analysis was demonstrated in cerebrospinal fluid (CSF), showcasing its efficacy and versatility as a biosensing tool with wide-ranging applications in disease diagnosis and bioanalysis.