Research Information System
Microchemical Journal, vol.226, 2026 (SCI-Expanded, Scopus)
We report an antimicrobial peptide (AMP)-based electrochemical biosensor for the detection of Aeromonas salmonicida using disposable screen-printed carbon electrodes (SPCEs) surface-engineered with a Zn-Fe layered double hydroxide/Ketjenblack (ZnFe-LDH/KB) nanocomposite. The ZnFe-LDH/KB hybrid was synthesized by coprecipitation, and the characterization studies were conducted by SEM, TEM, XRD, FTIR, and TGA for verification. The nanomaterial was drop-cast onto SPCEs to create a porous, conductive scaffold for peptide immobilization and interfacial signal amplification. Cyclic voltammetry and electrochemical impedance spectroscopy confirmed the stepwise surface modification and demonstrated improved electron-transfer properties after nanocomposite surface modification. Differential pulse voltammetry (DPV) enabled the analytical detection of A. salmonicida, producing a distinct and reproducible response attributed to peptide-mediated bacterial capture at the engineered interface, which depended on the loading concentration of the bacteria. Selective recognition of the AMP was validated against non-target controls. The results revealed that the AMP-biosensor system demonstrated a wide linear range from 1 CFU/mL to 105 CFU/mL, with the limit of detection (LOD) 0.73 CFU/mL and a strong calibration linearity (R2 > 0.98). The assay showed good reproducibility, with an RSD of 3.19%, and demonstrated negligible microbial interference from non-target aquaculture-relevant bacteria. Real-sample validation in seawater confirmed matrix-tolerant detection, with only modest deviations from PBS responses at lower bacterial concentrations, while the peptide-functionalized electrodes retained analytical stability for one month under refrigerated storage. The biosensor system remained stable for one month, preserving its original current peak intensity. The AMP sequence was synthesized, purified, and analytically characterized to ensure sequence fidelity and reproducible sensor fabrication. Ultimately, the combination of a coprecipitated ZnFe-LDH/KB nanocomposite, a compact peptide bioreceptor, and orthogonal kinetic validation delivers a scalable electrochemical platform for sensitive and selective bacterial detection that is readily compatible with low-cost, point-of-use monitoring.