Finger-Actuated Micropump of Constant Flow Rate without Backflow.

Area of Science:

• Microfluidics
• Biomedical Engineering
• Fluid Dynamics

Background:

• Microfluidic devices require precise fluid control for applications like interstitial fluid (ISF) extraction.
• Existing micropumps often face challenges with consistent flow rates and backflow, limiting their utility.
• Optimizing microfluidic performance necessitates understanding fluid dynamics, including head losses and pressure drops.

Purpose of the Study:

• To develop and characterize a finger-actuated micropump for reliable ISF extraction.
• To investigate the fluid dynamics governing the micropump's operation, focusing on flow consistency and backflow prevention.
• To evaluate the impact of microchannel design and reservoir integration on micropump performance metrics like diodicity.

Main Methods:

• Analytical modeling and computational fluid dynamics (CFD) simulations were employed.
• Experimental methods were used to validate simulation results and measure key performance parameters.
• Characterization included analysis of head losses, pressure drop, hydrogel swelling, and flow rate consistency.

Main Results:

• The finger-actuated micropump achieved a consistent flow rate of approximately 2.2 μL/min after 20 seconds of operation.
• Flow rate discrepancy between experimental and predicted values was found to be around 22%.
• Integration of serpentine microchannels and hydrogel reservoirs significantly increased diodicity (Di = 1.48 and 1.96, respectively) compared to Tesla structures (Di = 1.45), with no observed backflow.

Conclusions:

• The developed finger-actuated micropump demonstrates consistent flow and effective backflow prevention.
• The study highlights the importance of microchannel design and reservoir integration in enhancing microfluidic performance.
• The micropump's characteristics show promise for low-cost, portable microfluidic applications.