Optimised hyperbolic microchannels for the mechanical characterisation of bio-particles

Area of Science:

• Biophysics
• Microfluidics
• Rheology

Background:

• Bio-particle transport in viscous flows shows complex dynamics like deformation and orientation changes.
• Understanding these dynamics is vital for characterizing biological particle mechanics and suspension rheology.
• Generating controlled, long-duration straining flows in microfluidics is challenging.

Purpose of the Study:

• To develop and validate an innovative microfluidic approach for studying bio-particle dynamics under homogeneous straining flow.
• To enable precise characterization of microscopic mechanical and rheological properties of biological materials.
• To investigate the morphologic evolution of bio-particles in controlled flow environments.

Main Methods:

• Utilized numerically optimized microfluidic converging-diverging channels to generate homogeneous straining flow.
• Employed a microscope-based tracking method with a motorized stage and synchronized imaging system.
• Tracked individual bio-particles over extended distances with high-resolution imaging.

Main Results:

• Demonstrated experimentally that optimized microchannels create linear velocity streamwise gradients.
• Achieved extended regions of homogeneous elongation and compression along the channel centerline.
• Successfully characterized the dynamic behavior of diverse bio-particles including DNA, actin filaments, and protein aggregates.

Conclusions:

• The developed microfluidic approach effectively generates controlled homogeneous straining flows.
• This method is versatile for investigating the dynamics of various bio-particles relevant to biology.
• Provides a powerful tool for studying microscopic mechanical properties and rheological behavior.