Dual-amplification electrochemical sensor based on catalytic hairpin assembly and nanoporous gold for the detection of Acinetobacter baumannii

Acinetobacter baumannii ( A. baumannii ), a prevalent multidrug-resistant nosocomial pathogen, necessitates rapid and highly sensitive detection, which is crucial for clinical diagnosis and infection control. This study endeavors to develop a dual-amplification electrochemical sensor utilizing catalytic hairpin assembly (CHA) and nanoporous gold (NPG) to facilitate ultra-sensitive detection of A. baumannii . Initially, an NPG electrode characterized by a three-dimensional porous architecture and high specific surface area was fabricated through the dealloying method, enabling the first-stage substrate amplification. Subsequently, a CHA cyclic amplification system was introduced, the target gene sequence triggers cascade hybridization reactions between two hairpin probes (H1−H2), cyclically producing a substantial number of H1-H2 double-stranded complexes, thus achieving the second stage of signal amplification. Moreover, the recognition and amplification processes are integrated within a single system, offering the advantages of being enzyme-free and user-friendly. A limit of detection (LOD) as low as 70 CFU/mL was achieved with a good linear range (10(Scoffone et al., 2025a 2 –10(Wong et al., 2017 7 ). In samples of spiked artificial cerebrospinal fluid (CSF), recovery rates varied from 94.6% to 103.0%, underscoring its potential applicability in complex matrices. This study successfully developed a highly efficient dual-amplification sensing platform and offers a novel and reliable analytical approach for the rapid, on-site detection of A. baumannii .