Hydrodynamic focusing investigation in a micro-flow cytometer

Area of Science:

• Fluid dynamics
• Microfluidics
• Biomedical engineering

Background:

• Hydrodynamic focusing is crucial for micro-flow cytometry, enabling precise sample stream manipulation.
• Understanding fluid interactions within microfluidic devices is essential for optimizing cytometer performance.

Purpose of the Study:

• To develop and validate a two-fluid model for hydrodynamic focusing in micro-flow cytometers.
• To investigate the influence of various parameters on the focused sample stream width and flow characteristics.

Main Methods:

• A two-dimensional, laminar, incompressible, and isothermal two-fluid model was established.
• Transient conservation equations for mass and momentum were solved numerically using the SIMPLEC algorithm.
• Numerical experiments were conducted to analyze flow fields, pressure drops, and focusing times.

Main Results:

• The model accurately predicted focusing width and length, showing good agreement with experimental data.
• The study detailed the hydrodynamic focusing flowfield, pressure drop, and event completion time.
• Parameter variations demonstrated significant effects on the focused sample stream width.

Conclusions:

• The validated two-fluid model provides a robust tool for understanding and designing micro-flow cytometers.
• Numerical simulations offer valuable insights into optimizing hydrodynamic focusing for enhanced cytometer performance.