Development of an electrochemical sensitive aptasensor based on a zeolite imidazolate framework-8 and gold...

Staphylococcus aureus (S. aureus) is one of the most important pathogens that cause illness and food poisoning. In this research, using a glassy carbon electrode (GCE) modified with zeolite imidazolate framework-8 (ZIF 8) and gold nanoparticles (AuNPs), a sensitive electrochemical aptasensor has been made for the detection of the S. aureus bacteria. The morphology of the prepared AuNPs-ZIF 8 nanocomposite has been carefully characterized by means of transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). In the manufacturing process, the S. aureus aptamer is immobilized on the AuNPs-ZIF 8 surface. Electrochemical impedance spectroscopy (EIS) method has been used for quantitative determination of S. aureus bacteria. The changes in the charge transfer resistance (R_ct) of the aptamer due to the change in the concentration of bacteria are considered as the analytical signals. The proposed aptasensor has linear response in the concentration range of 1.5 × 10¹ to 1.5 × 10⁷ CFU mL^-1 of S. aureus bacteria. The detection limit of the method is 3.4 CFU mL^-1. Using the developed aptasensor, it is possible to determine S. aureus bacteria in water and milk samples.