A Bioartificial Organ Scaffold Architecture Design

We develop a diffuse interface approach to study the design of a bioartificial organ scaffold architecture. The scaffold consists of a poroelastic hydrogel with a network of ultrafiltrate channels. The flow of blood plasma through the channels is modeled using the time-dependent Stokes equations, and the flow of blood plasma through the poroelastic hydrogel is modeled by the Biot equations. The two are coupled via a two-way coupling across the linearized channel-hydrogel interface. The resulting blood plasma velocity is then used to calculate oxygen concentration within the scaffold via a diffuse interface advection-reaction-diffusion model for oxygen concentration in the scaffold. The goal is to investigate which geometry of the channels’ network with a given total channels’ volume/area provides the most uniform oxygen supply to the transplanted cells in the poroelastic hydrogel, with oxygen concentration above the critical concentration below which hypoxia occurs. We show that a hexagonal channel network geometry outperforms by far the branching channels’ network and the classical vertical channel geometries. We conclude that the main reason for the superior performance of the hexagonal geometry is a relatively large angle between the dominant channel flow direction and the channel-hydrogel interface, providing larger Darcy velocity and thus larger advection-enhanced oxygen supply to the transplanted cells. This study is significant because recent developments in hydrogel fabrication make it now possible to control hydrogel rheology [1, 2], and utilize the computational results providing optimized scaffold architectures.