Dynamics and rheology of vesicles in a shear flow under gravity and microgravity

Abstract

International audienceThe behaviour of a vesicle suspension in a simple shear flow between plates (Couette flow) was investigated experimentally in parabolic flight and sounding rocket experiments by Digital Holographic Microscopy. The lift force which pushes deformable vesicles away from walls was quantitatively investigated and is found to be rather well described by a theoretical model by Olla [1]. At longer shearing times, vesicles reach a steady distribution about the center plane of the shear flow chamber, through a balance between the lift force and shear induced diffusion due to hydrodynamic interactions between vesicles. This steady distribution was investigated in the BIOMICS experiment in the MASER 11 sounding rocket. The results allow an estimation of self-diffusion coefficients in vesicle suspensions and reveal possible segregation phenomena in polydisperse suspensions

Gravitational effect on the cell in bio-fluid suspension

“…Previously, there have been some computational studies on the effects of microgravity on osteoclasts [43]; however, there are no computational studies involving cells such as RBC and WBC in micro- or hypergravity regimes. Nevertheless, significant experimental advancements have been made on the impact of microgravity on vesicles and RBCs [13–15]. To corroborate the results of our investigation, a comparative analysis was carried out between the detachment and lift of the RBC and vesicles under the 1g condition of Losserand et al [44] (refer to Figure 1(c)) with the present work.…”

“…Therefore, understanding the association between cellular mechanics and mechanotransduction in microgravity is critical to solving the immune dysfunction puzzle. Microgravity research has primarily focused on experimental procedures, and studies have been done from a mechanics perspective on vesicles and RBCs [13][14][15] under microgravity. Similarly, some computational studies have been done on non-adherent cells such as stem cells [16] and bone/osteocytes [17][18][19][20]; their underlying biology has not been investigated.…”