Temperature-controlled MPa-pressure ultrasonic cell manipulation in a microfluidic chip

Area of Science:

• Biomedical Engineering
• Acoustic Physics
• Cell Biology

Background:

• Acoustophoresis utilizes ultrasonic standing waves for cell manipulation.
• Understanding the impact of acoustic parameters on cell viability is crucial for clinical applications.
• Previous studies have not fully decoupled temperature effects from acoustic pressure effects on cells.

Purpose of the Study:

• To investigate the temperature-independent effects of high-acoustic-pressure ultrasonic exposure on cell viability.
• To assess the safety of using ultrasonic standing waves for cell trapping and aggregation in microfluidic devices.
• To determine the maximum acoustic pressure amplitude and duration compatible with cell viability.

Main Methods:

• Utilized a microfluidic chip with a temperature-controlled ultrasonic transducer for stable 37 °C operation.
• Employed a light-intensity method with polymer beads for accurate acoustic pressure calibration.
• Monitored the viability of A549 lung cancer cells exposed to 1 MPa acoustic pressure for one hour.
• Measured acoustic streaming velocities around trapped cell aggregates.

Main Results:

• Acoustic pressures up to 1 MPa can be achieved using frequency-modulated ultrasonic actuation.
• A549 lung cancer cells maintained viability after one hour of exposure to 1 MPa acoustic pressure.
• Acoustic streaming velocities up to 100 μm s⁻¹ did not compromise cell viability.

Conclusions:

• High-magnitude acoustic pressure exposure in microfluidic devices is compatible with cell viability.
• Temperature-independent effects of acoustic fields on cells can be studied using controlled systems.
• These findings validate the use of acoustophoresis for biomedical applications requiring cell manipulation.