Liquid plug propagation in computer-controlled microfluidic airway-on-a-chip with semi-circular microchannels

Area of Science:

• Biomedical Engineering
• Respiratory Physiology
• Microfluidics

Background:

• Distal airway fluid dynamics are critical in lung diseases like COPD.
• Previous models lacked the ability to stably generate and analyze liquid plugs under physiologically relevant conditions.
• Understanding liquid plug behavior is essential for developing effective treatments for obstructive lung diseases.

Approach:

• Developed a novel two-inlet, one-outlet lung-on-a-chip device with computer-controlled fluidic switching.
• Engineered a leak-proof bonding protocol for culturing primary human small airway epithelial cells.
• Enabled stable, long-term generation and propagation of liquid plugs, including surfactant-laden ones.

Key Points:

• The device reproducibly generated surfactant-containing liquid plugs, showing reduced propagation pressure.
• Increased fluid viscosity decreased plug propagation speed and increased wall shear stress and pressure differentials.
• Channel geometry influenced epithelial cell injury, with greater damage in the center of semi-circular microchannels.

Conclusions:

• This lung-on-a-chip system advances the study of distal airway fluid mechanics and injury.
• The findings provide insights into the physiological impact of altered mucus viscosity and surfactant dysfunction in obstructive lung diseases.
• The platform facilitates the investigation of liquid plug dynamics and their role in respiratory mechanics.