Numerical analysis of the biomechanical effects on micro-vessels by ultrasound-driven cavitation

Purpose: The goal of this study was to evaluate the biomechanical effects such as sonoporation or permeability, produced by ultrasound-driven microbubbles (UDM) within microvessels with various parameters. Methods: In this study, a bubble-fluid-solid coupling system was established through combination of finite element method. The stress, strain and permeability of the vessel wall were theoretically simulated for different ultrasound frequencies, vessel radius and vessel thickness. Results: the bubble oscillation induces the vessel wall dilation and invagination under a pressure of 0.1 MPa. The stress distribution over the microvessel wall was heterogeneous and the maximum value of the midpoint on the inner vessel wall could reach 0.7 MPa as a frequency ranges from 1 to 3 MHz, and a vessel radius and an initial microbubble radius fall within the range of 3.5–13 μm and 1–4 μm, respectively. With the same conditions, the maximum shear stress was equal to 1.2 kPa and occurred at a distance of ±5 μm from the midpoint of 10 μm and the maximum value of permeability was 3.033 × 10–13. Conclusions: Results of the study revealed a strong dependence of biomechanical effects on the excitation frequency, initial bubble radius, and vessel radius. Numerical simulations could provide insight into understanding the mechanism behind bubble-vessel interactions by UDM, which may explore the potential for further improvements to medical applications.