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

Abstract

Asystem for the rapid and ultra-sensitive detection of Staphylococcus aureus (S. aureus), a prevalent foodborne pathogenis introduced. Limitations of typical electrochemical sensing, often subjected to interference from non-specific protein adsorptionare addressed. Adual-aptamer-based sandwich immunobiosensor is shown for its benefits regardingspecificity 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 5mM Fe(CN)63-/Fe(CN)64-, 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 × 101 to 1 × 105CFU/mL) and detection limit as low as 2CFU/mL. The resistance values of the immunobiosensor developed maintain at a stable value during 2weeks. 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.