Design and characterization of a flow silicone chamber for combined cell stimulation. a computational fluid dynamic analysis

Cells are able to sense and respond to mechanical stimuli occurring in their microenvironment via mechanotransduction, the cellular process by which the mechanical forces are converted in biological responses. The most relevant mechanical forces that the cells perceive are the substrate deformation and the fluid shear stress. A disruption in the capability to correctly respond to mechanical stimulations results in pathological conditions, including osteoporosis, developmental disorders, arthritis and cancer. Nowadays, the in vitro systems are employed to recreate the mechanical stimuli detected by the cells in a more controlled microenvironment. In this study, we propose the design and characterization of a flow silicone chamber, for shear stress and substrate deformation induction, that will be integrated in a system composed by a uniaxial stretching device and a flow pump system. The flow silicone chamber consists of a central fluidic region designed to have an inlet and an outlet, connected to the pump system and both communicating, through four lateral channels, with two cell channels with dimensions of 8x4 mm of length and width, respectively. Computational fluid dynamics (CFD) simulation tests were performed to evaluate the fluid shear stress distribution occurring on the surface of the chamber, where cells to be tested will be seeded. The analyses were performed by varying the dimension of the lateral channels height and the intensity of the volumetric flow rates. Our results revealed that the configuration with the lateral channels of 2 mm of height allowed to obtain the more homogeneous shear stress distribution and a reduced fluid turbulence.