Microfluidic Passive Valve with Ultra-Low Threshold Pressure for High-Throughput Liquid Delivery

Area of Science:

• Microfluidics
• Biomedical Engineering
• Mechanical Engineering

Background:

• Accurate flow control is crucial for cost-effective and miniaturized microfluidic devices.
• Existing microvalves often require complex mechanisms or higher operating pressures.
• There is a need for passive valves capable of precise regulation under low fluidic pressure.

Purpose of the Study:

• To propose and validate a novel microfluidic passive valve.
• To achieve high flow rate control with an ultra-low threshold pressure.
• To demonstrate the valve's stability under various pressure conditions and its application in low-cost systems.

Main Methods:

• Fabrication of a prototype microvalve using 3D printing and UV laser-cutting.
• Testing the microvalve under static and time-dependent pressure conditions (sinusoidal, square wave).
• Integration of the microvalve into a gas-driven flow system using low-cost gas sources (air blower, human breath).

Main Results:

• The microvalve demonstrated a nearly constant flow rate of 4.03 mL/min with ~4.22% variation under 6-12 kPa inlet pressures.
• Stable flow rate regulation was achieved under time-varying sinusoidal and square wave pressures.
• Successful steady flow delivery was regulated in a gas-driven system using low driving pressures.

Conclusions:

• The novel microfluidic passive valve effectively controls flow rate under ultra-low pressures.
• The valve's stability and performance make it suitable for portable microfluidic devices.
• This technology offers a cost-effective solution for flow regulation in diverse microfluidic applications.