Simultaneous Detection of Staphylococcus aureus and E. coli O157:H7 Using a Self-Calibrated Potentiometric Sensors Array Based on Peptide Recognition

Abstract

A novel self-calibrated potentiometric sensors array for simultaneous detection of staphylococcus aureus (SA) and E. coli O157:H7 (E. coli) based on peptide recognition have been proposed on a 4-channel screen printed carbon electrode (SPCE) modified with DenAu and PTAA. Two specific peptides for recognition of SA and E. coli were assembled on two working channels, respectively. For two calibration channels, two non-specific peptides with the same isoelectric point and length as the specific ones were coated on the surface to eliminate the influence of the background matrix on the potentiometric responses of working channels, and improve the detection accuracy. Under the optimal conditions, the sensors array exhibited high sensitivity to SA and E. coli in the range of 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> CFU/mL - 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> CFU/mL and 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> CFU/mL - 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> CFU/mL with the detection limits of 38 CFU/mL and 241 CFU/mL, respectively, and also good specificity and repeatability. Furthermore, it was successfully applied to the detection of milk samples, providing an effective strategy the on-site simultaneous detection of multiple targets.