Deformation behaviour of soft particles: a review

The study of soft particle deformation is of paramount importance for the advancement of fundamental colloidal science as well as its biomedical applications, particularly in drug delivery and cell mechanics/adhesion. Recent developments of both theoretical modelling and experimental techniques have made it possible to measure the deformation behaviour of a single micro-/nano-particle under both adhesive and non-adhesive deformation and, therefore, to facilitate the determination of its mechanical and interfacial properties. This review aims to introduce several modern experimental techniques, such as atomic force microscopy, the micro-compression method and reflectance interference contrast microscopy, and a number of theoretical models, which have been applied to characterize the mechanical and interfacial properties of the soft particles in a quantitative manner. More specifically, their recent applications to biomimetic/biological particles or vesicles, which normally inherit non-linear elasticity and inhomogeneous structure, will also be reviewed.