Boosted electrocatalytic activity on FeCoNi LDHs incorporating Cd deposition for Staphylococcus aureus detection

Electrochemical detection of foodborne pathogens requires simplified electrode modification and enhanced sensitivity. This study introduced Cd-decorated ternary FeCoNi layered double hydroxides (Cd-FeCoNi LDHs) platform for label-free Staphylococcus aureus (S. aureus) detection via Cu²⁺ biosorption. The FeCoNi LDHs were engineered with optimized metal sites to create lamellar structures with high electrocatalytic surface area. Further incorporating with Cd particles deposition, the response of the Cd-FeCoNi LDHs to Cu²⁺ exhibited a double-enhanced differential pulse voltammetry signal. Concurrently, S. aureus has been explored to adsorb Cu²⁺ through surface carboxyl and phosphate groups. By integrating with specific magnetic separation, the variation of Cu²⁺ derived from biosorption by S. aureus triggered the rapid electrical response of the Cd-FeCoNi LDHs platform. This approach achieved 5.4 CFU/mL detection without bio-labeling, while resisting matrix interference. This work highlighted the innovative application of bacterial metal ions biosorption and label-free sensing platform for foodborne pathogen detection.