Electrochemical sensing of Staphylococcus aureus based on conductive anti-fouling interface

A system for the rapid and ultra-sensitive detection of Staphylococcus aureus ( S. aureus ), a prevalent foodborne pathogen is introduced. Limitations of typical electrochemical sensing, often subjected to interference from non-specific protein adsorption are addressed. A dual-aptamer-based sandwich immunobiosensor is shown for its benefits regarding specificity and anti-fouling capacity, endowed by a sulfonated polyaniline layer combined with signal amplification via highly conductive gold nanoparticles. EIS spectra (Nyquist plots) were recorded at pH 7.4 PBS containing 5 mM Fe(CN) 6 3− /Fe(CN) 6 4− , in order to verify the possibility of the electrochemical sensing for detection of S. aureus. Results demonstrated that the constructed immunobiosensor presents an extended detection range (1 × 10 1 to 1 × 10 5  CFU/mL) and detection limit as low as 2 CFU/mL. The resistance values of the immunobiosensor developed  maintain at a stable value during 2 weeks.  Besides, the specificity of the system is highlighted by testing raw milk, and the results of which demonstrate the excellent prospects of the system for monitoring foodborne pathogens. Graphical abstract