Two microgel particles are encapsulated in a microdrop having a spherical diameter smaller than the
sum of the diameters of the microgels; this causes the microgels to be squeezed together by the oil–water
interface of the drop, in turn, making the drop ellipsoidal in shape. By modeling the force applied to the
microgels by the drop and equating this to the Hertz contact force of their deformation, we are able to
estimate their elastic modulus. By varying the surface tension and shape of the drops, we are able to
measure the modulus of the microgels under different loads. This provides a simple technique for
quantifying the elasticity of small, deformable objects, including liquid drops, microgels, and cells.
For more details, please see:
Adam R. Abate, Lloyd Han, Lihua Jin, Zhigang Suo and David A. Weitz. Measuring the elastic modulus of microgels using microdrops. Soft Matter 8, 10032-10035 (2012).