# Microfluidic Chamber Design for Organ-on-a-Chip: A Computational Fluid Dynamics Study of Pillar Geometry and Pulsatile Perfusion

## TL;DR

This study uses computational modeling to optimize microfluidic chamber designs for organ-on-a-chip systems, focusing on how geometry and pulsatile flow affect cell environments.

## Contribution

The study introduces a computational fluid dynamics approach to evaluate pillar geometries and pulsatile perfusion effects in organ-on-a-chip systems.

## Key findings

- Pillarized chambers significantly reduce relative residence time compared to flat chambers.
- Small pillar configurations yield the most uniform wall shear stress distribution.
- Pulsatile flow patterns vary with waveform phase, highlighting limitations of steady inflow assumptions.

## Abstract

Organ-on-a-Chip (OOC) platforms are microfluidic systems that recreate key features of human organ physiology in vitro via controlled perfusion. Fluid mechanical stimuli strongly influence cell morphology and function, making this important for cardiovascular OOC applications exposed to pulsatile blood flow. However, many existing OOC devices employ relatively simple chamber geometries and steady inflow assumptions, which may cause non-uniform shear exposure to cells, create stagnant regions with prolonged residence time, and overlook the specific effects of pulsatile perfusion. Here, we used computational fluid dynamics (CFD) to investigate how chamber geometry and inflow conditions shape the near-wall flow environment on a cell culture surface at a matched cycle-averaged volumetric flow rate. Numerical results demonstrated that pillarized chambers markedly reduced relative residence time (RRT) versus the flat chamber, and the small pillar configuration produced the most uniform time-averaged wall shear stress (TAWSS) distribution among the tested designs. Phase-resolved analysis further showed that wall shear stress varies with waveform phase, indicating that steady inflow may not capture features of pulsatile perfusion. These findings provide practical guidance for pillar geometries and perfusion conditions to create more controlled and physiologically relevant microenvironments in OOC platforms, thus improving the reliability of cell experimental readouts.