Poroelastic longitudinal wave equation for soft living tissues

Abstract

Making use of the poroelastic theory for hydrated polymeric matrices, the ultrasound (US) propagation in a gel medium filled by spherical cells is studied. The model describes the connection between the poroelastic structure of living tissues and the propagation behavior of the acoustic waves. The equation of fast compressional wave, its phase velocity and its attenuation as a function of the elasticity, porosity and concentration of the cells into the gel external matrix are investigated. The outcomes of the theory agree with the measurements done on Alginic acid gel scaffolds inseminated by porcine liver cells at various concentrations. The model is promising in the quantitative non-invasive estimation of parameters that could assess the change in the tissue structure, composition and architecture.Keywords ultrasound, non-invasive assessment of biological tissue, poroelastic model of living tissues, high frequency poroelastic waves in soft tissues

Multi-length scale structural investigation of lysozyme self-assembly

“…The molecular and structural changes of LYS in solution have a strong influence on the interactions occurring between the monomers and the surrounding hydration water molecules. Indeed, conformational changes have an impact on the macroscopic viscoelasticity, and therefore influence the propagation of the sound wave into the sample ( Chiarelli et al., 2010 , 2014 ). Figure 1 C shows the HD-TG signal at low and high temperatures, whereas Figure 1 F reports the thermal dependence of the viscosity coefficient, D V , for the two investigated wave vectors, 2.1 μm -1 and 1.4 μm -1 , comparing the trend of the LYS 120 solution with that of the pure solvent.…”