Capillary micromechanics: Measuring the elasticity of microscopic soft objects

TL;DR

This paper introduces a straightforward technique to measure the elastic properties of microscopic soft particles by observing their deformation in a tapered microcapillary, enabling simultaneous determination of compressive and shear moduli.

Contribution

It presents a novel, simple method for measuring elastic properties of microscopic deformable particles using pressure-induced deformation in a microcapillary.

Findings

Excellent agreement with bulk gel measurements

Applicable to a wide range of mechanical properties

Potential for characterizing soft and biological materials

Abstract

We present a simple method for accessing the elastic properties of microscopic deformable particles. This method is based on measuring the pressure-induced deformation of soft particles as they are forced through a tapered glass microcapillary. It allows us to determine both the compressive and the shear modulus of a deformable object in one single experiment. Measurements on a model system of poly-acrylamide microgel particles exhibit excellent agreement with measurements on bulk gels of identical composition. Our approach is applicable over a wide range of mechanical properties and should thus be a valuable tool for the characterization of a variety of soft and biological materials.