INFLUENCE OF CAVITATION BUBBLE DYNAMICS IN A MICROSCOPIC LIQUID CELL ON THE ELASTIC STRESSES IN A POLYMER ENCAPSULATION SHELL
K.V. Leonov1, I.Sh. Akhatov1,2,3
1Moscow Center of Fundamental and Applied Mathematics, Moscow State University (MSU), Moscow, Russia
2Bashkir State Medical University, Ufa, Russia
3Kazan National Research Technical University, Kazan, Russia
Keywords: bubble dynamics, cavitation, ultrasound, targeted drug delivery
Abstract
A new microcapsule design for targeted drug delivery is proposed and investigated. The design consists of a spherical liquid cell (drug solution) containing a nanobubble, encapsulated in a polymer shell. The effect of low- and high-frequency ultrasound on the cavitation bubble dynamics in a confined liquid volume and the resulting elastic tangential (circumferential) stresses in the polymer shell is analyzed. It is found that a relatively weak external ultrasound stimulus can be significantly amplified inside the microcapsule due to explosive cavitation growth of the bubble. The most significant amplification and, consequently, the maximum tangential stresses in the shell are achieved using low-frequency (approximately 20 kHz) ultrasound and a thin shell. It is shown that, in the presence of a cavitation bubble, the mechanical stresses in the shell are many times greater than in a capsule filled with liquid alone.
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