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Electrochemical pH regulation in droplet microfluidics
Logan M Wilder1, Jonathan R Thompson1, Richard M Crooks1
1Department of Chemistry and the Texas Materials Institute, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712-1224, USA. crooks@cm.utexas.edu.
Lab on a Chip
|January 12, 2022
Summary
This study introduces electrochemical pH control in microfluidic droplets. Researchers precisely adjusted droplet pH by generating reagents electrochemically within moving microdroplets.
Area of Science:
- Microfluidics
- Electrochemistry
- Biotechnology
Background:
- Microfluidic devices enable precise control over small fluid volumes.
- Electrochemical methods offer a way to generate reagents in situ.
- Controlling pH in microdroplets is crucial for various applications.
Purpose of the Study:
- To develop a method for electrochemical pH regulation in microdroplets.
- To demonstrate the controlled generation and isolation of electrochemical products within microdroplets.
- To explore the adaptability of this technique for generating other reagents.
Main Methods:
- Generating approximately 5 nL water-in-oil microdroplets at a T-junction.
- Splitting microdroplets into two descendant droplets.
- Utilizing floor-patterned microelectrodes for water electrolysis and pH modification within droplets.
- Regulating pH by injecting controlled amounts of electrical charge.
Main Results:
- Successfully regulated microdroplet pH over a range of 5.9 to 7.7.
- Achieved pH prediction accuracy within ±0.1 pH units for injected charges between -6.3 and 54.5 nC nL⁻¹.
- Demonstrated isolation of anodic and cathodic products within descendant microdroplets.
Conclusions:
- Electrochemical pH regulation is feasible in microfluidic systems.
- This method allows for precise control and generation of reagents within microdroplets.
- The technique holds potential for broader applications in reagent generation for microfluidic assays.
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