Single microbubble measurements of temperature dependent viscoelastic properties

摘要

We show here that temperature influences single microbubble dynamics by changing lipid shell viscoelastic properties. A newly developed photoacoustic measurement technique drove individual microbubbles into small-amplitude oscillations through ultrasound waves generated by the absorption of an amplitude-modulated laser. Forward light scattering was used to detect bubble oscillations as the modulation frequency was swept across a two megahertz range in order to construct a resonance curve. Microbubble size, resonance frequency, and damping ratio were measured and then used to determine shell elasticity and viscosity by modeling the microbubble as a linear harmonic oscillator. Viscoelastic properties were shown to decrease nearly linearly between 20 to 52 degrees Celcius. These findings may be used to better understand microbubble dynamics for applications in biomedical ultrasound.