High Strain-rate Soft Material Characterization via Inertial Cavitation*

Mechanical characterization of soft materials at high strain-rates is challenging due to their high compliance, slow wave speeds, and non-linear viscoelasticity; however, knowledge of their material behavior is paramount across a spectrum of biological and engineering applications. To address this significant experimental hurdle and accurately measure the viscoelastic properties of soft materials at high strain-rates, we present a minimally invasive, local, 3D microrheology technique based on inertial microcavitation. By combining high-speed time-lapse imaging with a theoretical cavitation-modeling framework, we demonstrate that this technique has the capability of accurately determining the viscoelastic material properties of soft matter as compliant as a few kilopascals at high strain-rates. Given its straightforward implementation into most current microscopy setups, we anticipate that this technique may be easily adopted by researchers interested in characterizing soft material properties at high loading rates including hydrogels, tissues, and various polymeric specimens.