Optimization of Microfluidics for Point-of-Care Blood Sensing.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Analytical Chemistry

Background:

• Point-of-care (PoC) blood testing is crucial for remote diagnostics.
• Current PoC devices often require active pumps, increasing cost and size.
• Efficient processing of small blood volumes is needed for portable diagnostics.

Purpose of the Study:

• To investigate capillary structures for passive, pump-free processing of whole blood.
• To optimize microfluidic chip design for rapid blood sample uptake.
• To enable faster and more accessible blood testing at the point of care.

Main Methods:

• Simulated capillary pump pillar shapes using Ansys Fluent for optimal blood uptake.
• Fabricated microfluidic chips from polydimethylsiloxane (PDMS) and polyethylene oxide (PEO).
• Experimentally measured chip filling times using water and whole blood.

Main Results:

• Pillar shape significantly influences chip filling time; high aspect ratio structures showed faster uptake.
• Fabricated chips achieved uptake times of 24 s for water and 111 s for 2 μL whole blood.
• Simulation of blood plasma deviated by ~35% from experimental results, highlighting cell-induced effects.

Conclusions:

• Passive capillary structures offer a viable alternative to active pumps for microfluidic blood sample processing.
• Optimized pillar geometry is key for efficient fluid handling in microfluidic devices.
• This research provides insights for designing advanced passive microfluidic systems for whole blood analysis in sensing applications.