INVESTIGATION OF SPHERICAL BUBBLE DYNAMICS UNDER BIOLOGICAL ENVIRONMENT BASED ON RAYLEIGH-PLESSET EQUATION

Cavitation in vivo has a wide range of application prospects in the biomedical field, such as non-invasive lithotripsy, extracorporeal shock wave therapy and target drug delivery. However, the mechanism of the influence of biological environment, such as blood and interstitial fluid, on the bubble's dynamic behaviour is still not fully revealed. In this work, the kinetic process of spherical symmetric bubble in blood under the action of ultrasonic driving pressure field is investigated based on the classical Rayleigh-Plesset equation. The influences of the liquid viscosity and the surface tension on the bubble dynamical properties are discussed in detail. It is found that liquid viscosity and surface tension have different effects on bubble dynamics, where the viscosity of liquid dominates the attenuation of bubble's oscillation amplitude, while the surface tension primary influences the responding time of bubble. Since the stronger viscosity and surface tension related to the longer responding time, the oscillation amplitude of the bubble would be significantly smaller in blood than that in water. This study of the dynamical characteristics of bubble in different fluids might help to understand cavitation behaviour in biomedical applications.