Interdigitated Array microelectrode-based electrochemical impedance immunosensor for detection of Escherichia coli...

Area of Science:

• Electrochemistry
• Biosensing
• Microfluidics

Background:

• Escherichia coli O157:H7 is a significant foodborne pathogen.
• Rapid and sensitive detection methods are crucial for public health.
• Electrochemical impedance spectroscopy (EIS) offers label-free detection capabilities.

Purpose of the Study:

• To develop a label-free electrochemical impedance immunosensor for rapid detection of Escherichia coli O157:H7.
• To immobilize anti-E. coli antibodies onto an indium-tin oxide interdigitated array (IDA) microelectrode.
• To correlate impedance changes with bacterial concentration.

Main Methods:

• Immobilization of anti-E. coli antibodies on an indium-tin oxide IDA microelectrode.
• Electrochemical impedance spectroscopy (EIS) using [Fe(CN)(6)](3-/4-) as a redox probe.
• Analysis of impedance components using an equivalent circuit model.

Main Results:

• Antibody immobilization and E. coli O157:H7 binding increased electron-transfer resistance.
• A linear correlation was observed between electron-transfer resistance and E. coli O157:H7 concentration (4.36 x 10^5 to 4.36 x 10^8 cfu/mL).
• A detection limit of 10^6 cfu/mL was achieved.

Conclusions:

• The developed label-free electrochemical impedance immunosensor provides a rapid and sensitive method for E. coli O157:H7 detection.
• The IDA microelectrode coupled with EIS is effective for monitoring bacterial binding events.
• This technology holds potential for food safety and clinical diagnostics.