Membrane-mediated hydrodynamic shear transmission to cells

Hydrodynamic shear regulates cellular remodeling and mechanotransduction, yet externally prescribed wall shear stress does not uniquely specify the mechanical stimulus transmitted through the plasma membrane to the cell interior. Here, we develop a reduced-order multiscale framework in which the plasma membrane functions as a mechanically responsive hydrodynamic transmission layer rather than a passive geometric boundary. An effective interfacial slip condition and a first-order membrane thickness-dependent attenuation relation yield closed-form expressions linking external shear to membrane slip velocity, transmitted intracellular velocity, effective strain, forcing frequency, membrane properties, and cellular geometry. A steady-flow extension distinguishes the membrane-mediated mechanical input from slower cytoskeletal remodeling. Comparison with independent endothelial and epithelial studies conducted under shear stresses of approximately 4–15 dyn cm−2 demonstrates qualitative consistency with rapid subcellular structural responses, slower hour-scale remodeling, and substantial variability among cellular systems exposed to comparable external loading. Because the published studies do not report the membrane parameters required for direct evaluation of the model, these comparisons are presented as literature-constrained consistency tests rather than quantitative validation. The framework provides a testable continuum-mechanics description of hydrodynamic transmission from extracellular flow toward the membrane–cortex region, thereby specifying a mechanical input that may subsequently engage established cellular mechanotransduction pathways.