Surface-area-dependent viscoelastic property characterization of monodisperse microbubbles with different...

Area of Science:

• Biomedical Engineering
• Materials Science
• Acoustics

Background:

• Microbubble acoustic response is sensitive to shell viscoelasticity, critical for ultrasound imaging and therapy.
• Limited understanding exists regarding nonlinear, surface-area-dependent shell viscoelasticity.

Purpose of the Study:

• To characterize the surface-area-dependent viscoelastic properties of microbubble shells.
• To establish guidelines for tailoring phospholipids for microbubble design.

Main Methods:

• Fabrication of monodisperse microbubbles (MDMBs) with varying phospholipid shells using microfluidics.
• Analysis of resonance frequency shifts to assess shell compression state.
• Characterization of viscoelastic properties via fitting a linearized oscillation model to pressure-dependent attenuation spectra.

Main Results:

• Shell elasticity and viscosity showed complex changes upon expansion and compression.
• Surface tension increased upon expansion and decreased upon compression.
• Elasticity was radius-independent but lipid-dependent; viscosity increased with radius.
• Initial surface tension depended on acyl chain length.

Conclusions:

• Phospholipid composition significantly impacts microbubble shell viscoelasticity.
• Findings provide a framework for standardized characterization and tailored phospholipid selection for microbubble development.
• This research aids in designing advanced microbubbles for ultrasound applications.