A Multi-Phasic Continuum Damage Mechanics Model of Mechanically Induced Increased Permeability in Tissues

Published

December 30, 2005

Author(s)

Brian O'Neill, Timothy P. Quinn, Victor F. Frankel, King C. Li

Abstract

Recently, we have reported enhanced permeability of tissues due to in vivo treatment with pulsed high intensity focused ultrasound (pHIFU). This new therapy has shown promise as a way of increasing the penetration of large drug molecules both out of the vasculature and into the tissue. To date, no clear physical model of tissue exists that can account for these effects. A new model is proposed that clearly establishes the link between tissue structure and fluid flow properties on one hand, and the history of applied mechanical forces on the other. The model draws inspiration from two different theoretical fields of materials science, multi-phase theory and continuum damage mechanics. The theory differs from the traditional bi-phasic solid-fluid model of tissues in that the fluid part here is broken into trapped (moving with the solid) and free (moving through the solid) parts. A damage-like variable links the effective elasticity of the tissue to the ratio of the trapped to free fluids. As the damage increases, the tissue becomes, in effect, less stiff and more permeable. Elastic energy is released, which drives the process. A distribution of energy barriers opposes the process and governs how the fluid is released as damage increases.

Proceedings Title

Proceedings of the 2005 Fall MRS Meeting

Volume

898E

Conference Dates

November 28-December 2, 2005

Conference Location

Boston, MA, USA

Conference Title

2005 MRS Fall Meeting

Pub Type

Conferences

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Keywords

high intensity focused ultrasound, therapeutic ultrasound

Citation

O'Neill, B. , Quinn, T. , Frankel, V. and Li, K. (2005), A Multi-Phasic Continuum Damage Mechanics Model of Mechanically Induced Increased Permeability in Tissues, Proceedings of the 2005 Fall MRS Meeting, Boston, MA, USA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50254 (Accessed May 13, 2025)