Biomechanics of microvasculature on blood vessel-on-a-chip*

We use a three-dimensional 3D model blood vessel platform to measure the elasticity and membrane permeability of the endothelial cell layer. The microfluidic platform is connected to a pneumatic pressure controller to apply hydrostatic pressure. The deformation is measured by tracking the mean vessel diameter under varying pressures up to 300 Pa. We obtain a value for the Young's modulus of the cell layer in low strain where a linear elastic response is observed and use a hyperelastic model that describes the strain hardening observed at larger strains. Fluorescent dye is used to track the flow through the cell layer while pressurized to determine the membrane flow resistance as a function of applied pressure. Finally, we track the 3D positions of cell nuclei while the vessel is pressurized to observe local deformation and correlate inter-cell deformation with the local structure of the cell layer. This approach can probe the mechanical properties of blood vessels in vitro and provides a methodology for investigating microvascular related diseases.