A parameter study of the material properties in the vesicle-fluid interaction

Simulation of a deformable vesicle by laser trapping in a Newtonian fluid is performed by the finite element analysis (FEA). The vesicle is modeled as a sphere with two incompressible, Mooney-Rivilin materials to represent the lipid bi-layer membrane and cytoskeleton of a cell. Several parameters such as the Reynolds number, the ratios of Young's modulus and Mooney-Rivilin coefficients are used for a systematic numerical study on the interaction between the fluid and vesicle. Results show that the vesicle deformation is highly localized near the laser-trapping region and it results in a local negative pressure gradient if the membrane's stiffness is low. Corresponding stress analysis also reveals that the deformation mechanism in membrane changes from bending to stretching along the circumferential direction. Finally, it is found that Mooney-Rivilin coefficients of cytoskeleton have a dominated influence on the part of non-linear deformation of vesicle if the stiffness of membrane is low.