A fluidic diode, valves, and a sequential-loading circuit fabricated on layered paper

Area of Science:

• Biomedical Engineering
• Materials Science
• Fluid Dynamics

Background:

• Microfluidic paper-based devices (µPBDs) are cost-effective diagnostic tools but often lack sophisticated fluid control.
• Existing µPBDs struggle with precise manipulation and sequential delivery of multiple reagents.
• The development of passive fluidic components is crucial for advancing µPBD functionality.

Purpose of the Study:

• To design and fabricate a novel fluidic diode entirely on a single layer of paper.
• To demonstrate the diode's ability to control fluid wicking in paper-based channels.
• To integrate the diode into functional circuits for sequential fluid manipulation.

Main Methods:

• Fabrication of a passive fluidic diode using a single layer of paper.
• Characterization of the diode's performance in promoting or inhibiting fluid wicking.
• Construction of trigger and delay valves based on the fluidic diode.
• Assembly of a functional circuit integrating the diode and delay valve for sequential fluid delivery.

Main Results:

• Successful fabrication of a paper-based fluidic diode capable of directional fluid control.
• Demonstration of the diode's ability to act as a one-way valve for controlling wicking.
• Development of functional trigger and delay valves utilizing the fluidic diode.
• Proof-of-concept demonstration of a circuit for sequential manipulation of two fluids.

Conclusions:

• The paper-based fluidic diode offers a transformative solution for fluid control in µPBDs.
• This component enables the development of more complex and functional paper-based analytical devices.
• The study provides essential tools for advancing microfluidics in low-cost diagnostic applications.