Porous microfluidics: A unique platform for transvascular study

This work reports the development of a porous microfluidic system which can serve as an in vitro model of natural vessels in circulatory and respiratory systems. The model possesses both structural and mechanical characteristics of the natural counterparts. To mimic the semi-permeable wall of natural vessels, microfluidic channels with porous walls are fabricated by spinning polymeric nanofibers on the collecting substrate with three-dimensional microelectrodes. The mechanical properties of the porous substrate are evaluated using conventional tensile testing. The permeability of the fibrous membrane is characterized by perfusion experiments. The results collectively show the utility of the membrane in transvascular study. Human umbilical vein endothelial cells (HUVECs) are cultured on the fibrous membrane and form an endothelial monolayer. The resulting structure is elastic and distensible, similar as natural blood vessels. The curved endothelium surface also helps to mimic the complex mechanical loading states of natural vascular endothelium under pulsatile flow. This work is expected to add a new dimension to the widely used microfluidic systems by allowing both in-vessel transport and trans-vessel transport. The immediate impacts of the porous microfluidic systems can be found in in vitro study of circulatory and respiratory systems.