Dean vortex-enhanced blood plasma separation in self-driven spiral microchannel flow with cross-flow microfilters

Area of Science:

• Biomedical Engineering
• Microfluidics
• Diagnostic Devices

Background:

• Point-of-care (POC) diagnostics are advancing, but often rely on saliva, not blood.
• Blood plasma separation for POC devices faces challenges like cell clogging and high viscosity, hindering efficiency.
• Current microfiltration methods struggle with high hematocrit blood, reducing speed and effectiveness.

Purpose of the Study:

• To investigate a power-free microfluidic dilution method for whole blood.
• To improve blood plasma separation efficiency for POC diagnostic applications.
• To address limitations of microfiltration in blood processing.

Main Methods:

• Implemented a spiral microchannel design utilizing inertial focusing and Dean vortex effects.
• Experimentally investigated particle inertial migration in capillary flow.
• Tested whole blood samples within physiological hematocrit ranges in optimized microchannels.

Main Results:

• Achieved a maximum of 88% particle migration to equilibrium positions in an optimized 350 × 60 μm microchannel.
• Demonstrated over 10% hematocrit reduction between outer and inner branch outlets in the optimized microchannel.
• Successfully reduced hematocrit in whole blood samples without external power.

Conclusions:

• The developed microfluidic device effectively reduces blood hematocrit using passive methods.
• This approach shows promise for enhancing blood plasma separation in power-free POC diagnostic systems.
• The findings support the expansion of blood-based POC diagnostics.