An inkjet-printed electrowetting valve for paper-fluidic sensors

Area of Science:

• Bioengineering
• Microfluidics
• Analytical Chemistry

Background:

• Paper-fluidic devices offer portability and low cost for micro total analysis systems (microTAS).
• Controlling fluid flow rate remains a key challenge in paper-fluidic device development.
• Electrowetting on dielectrics can alter surface properties from hydrophobic to hydrophilic.

Purpose of the Study:

• To develop a method for controlling fluid flow in paper-fluidic devices using electrowetting.
• To fabricate and test electrowetting-based valves for fluid control.
• To integrate these valves into a lateral flow assay for detecting specific biomarkers.

Main Methods:

• Fabrication of paper-fluidic devices using inkjet printing and spraying techniques.
• Integration of conductive hydrophobic electrodes/valves and hydrophilic electrodes.
• Actuation of valves via applied electrical potential to alter a fluorinated monolayer.
• Testing fluid front progression and valve response to varying electrical potential and electrode distance.
• Incorporation of valves into a lateral flow assay for Saccharomyces cerevisiae rRNA detection.

Main Results:

• Electrowetting valves successfully controlled the fluid front of phosphate-buffered saline (PBS).
• Increased applied potential reduced the time for fluid to pass the valve.
• No significant difference in fluid flow time was observed with increased electrode distance.
• The developed valves were successfully integrated into a lateral flow assay for rRNA detection.

Conclusions:

• Electrowetting on dielectrics provides a viable method for precise fluid flow control in paper-fluidic devices.
• This technology enhances the potential for developing complex assays for biomedical, food, and environmental applications.
• The developed paper-fluidic devices show promise for disease detection in resource-limited settings.