Flow of artificial microcapsules in microfluidic channels: A method for determining the elastic properties of the membrane

Abstract

The paper deals with a method to characterize the membrane mechanical properties of microcapsules. The technique consists in flowing microcapsules into a microchannel of comparable dimensions, observing the deformation as a function of the flow rate, and deducing the membrane elastic modulus by means of an inverse method based on a numerical model of the flowing capsule. The method is tested on liquid-filled microcapsules (average diameter of 67 μm) with a membrane made of crossed-linked ovalbumin flowing inside a cylindrical channel. For a neo-Hookean constitutive law, the method yields a constant value for the membrane shear elastic modulus independently of capsule size or deformation. When the capsules are flowed into a square-section microchannel, an approximate analysis of the deformation yields the same value of the membrane shear modulus provided that the size ratio between the capsule and the channel is of order unity.