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

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 has been proposed on a four-channel screen printed carbon electrode (SPCE) modified with dendrimer gold (DenAu) and polythiophene acetic acid (PTAA). Two specific peptides for the recognition of SA and E. coli were assembled on two working channels, respectively. For two calibration channels, two nonspecific 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
$1.0\times 10^{{2}}$
–
$1.0\times 10^{{6}}$
and
$1.0\times 10^{{3}}$
–
$1.0\times 10^{{5}}$
CFU/mL with the detection limits of 38 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 for the on-site simultaneous detection of multiple targets.