Dynamics of magnetic microbubble transport in blood vessels

Magnetic microbubbles(MMBs)can be controlled and directed to the target site by a suitable external magnetic field,and thus have potential in therapeutic drug-delivery application.However,few studies focus on their dynamics in blood vessels under the action of magnetic and ultrasonic fields,giving little insight into the mechanism generated in diagnostic and therapeutic applications.In this study,equations of MMBs were established for simulating translation,radial pulsation and the coupled effect of both.Meanwhile,the acoustic streaming and shear stress on the vessel wall were also presented,which are associated with drug release.The results suggest that the magnetic pressure increases the bubble pulsation amplitude,and the translation coupled with pulsation is manipulated by the magnetic force,causing retention in the target area.As the bubbles approach the vessel wall,the acoustic streaming and shear stress increase with magnetic field enhancement.The responses of bubbles to a uniform and a gradient magnetic field were explored in this work.The mathematical models derived in this work could provide theoretical support for experimental phenomena in the literature and also agree with the reported models.