3D interdigitated electrode array in the microchannel free of reference and counter electrodes

Area of Science:

• Electrochemistry
• Biosensing
• Materials Science

Background:

• Traditional electrochemical detection systems often require cumbersome reference and counter electrodes.
• Chip-based electrochemical detection faces challenges in miniaturization and simplicity.
• Developing electrode configurations that simplify electrochemical systems is crucial for practical applications.

Purpose of the Study:

• To demonstrate a three-dimensional interdigitated array (3D IDA) chip operating without reference and counter electrodes.
• To establish a simplified two-electrode (2E) electrochemical system for sensitive detection.
• To validate the 3D IDA chip as a platform for electrochemical immunosensing.

Main Methods:

• Fabrication of a 3D IDA chip with immobilized poly(methylene green) (PMG) and poly(dopamine) (PDA) on an ITO surface via electropolymerization.
• Development of a two-electrode (2E) system where the electron transfer mediator defines the electrochemical potential.
• Utilizing the 3D IDA chip in a microchannel for electrochemical immunosensing of Creatine Kinase-MB in human serum.

Main Results:

• The 3D IDA chip successfully operated in a two-electrode (2E) configuration without external reference or counter electrodes.
• The immobilized PMG/PDA system effectively controlled the electrochemical potential.
• The platform achieved sensitive detection of Creatine Kinase-MB in human serum down to approximately picogram per milliliter levels.

Conclusions:

• The 3D IDA chip in a 2E system offers a simplified, scalable, and sensitive platform for electrochemical detection.
• This technology requires only nanoliter sample volumes, making it suitable for miniaturized multiplex immunoassays.
• The developed system overcomes limitations of traditional electrochemical setups for chip-based sensing.