Electrochemical detection on electrowetting-on-dielectric digital microfluidic chip

Area of Science:

• Analytical Chemistry
• Microfluidics
• Electrochemistry

Background:

• Electrochemical sensing offers sensitive detection but can be limited by sample manipulation.
• Digital microfluidic devices provide precise control over small fluid volumes.
• Integrating these technologies can enhance analytical capabilities.

Purpose of the Study:

• To develop and demonstrate a combined electrowetting-on-dielectric (EWOD) digital microfluidic and electrochemical sensing system.
• To enable rapid quantitative analysis of iodide.
• To minimize reagent consumption in chemical analysis.

Main Methods:

• Fabrication of EWOD chips with silver electrodes on a glass substrate, coated with hydrophobic PDMS and Teflon films.
• Design of a T-junction EWOD mixer for reagent and analyte droplet manipulation.
• Integration of a three-electrode electrochemical system (Au working, Ag reference, Pt auxiliary) with the EWOD device.
• Quantitative analysis of iodide using cyclic voltammetry after droplet mixing and transport via EWOD.

Main Results:

• Successful mixing and transport of buffer and iodide solution droplets using EWOD within seconds at 300V.
• Accurate quantitative analysis of varying iodide concentrations via cyclic voltammetry.
• Demonstration of rapid chemical analysis with significantly reduced reagent volumes.

Conclusions:

• The combination of EWOD digital microfluidics and electrochemical sensing is effective for rapid iodide analysis.
• This integrated system offers a promising platform for microscale chemical analysis.
• The approach minimizes reagent use and processing time, enhancing analytical efficiency.