A 2D microfluidic model of cerebrospinal fluid motion in periarterial spaces

The glymphatic system is a pathway for metabolic waste clearance in the brain. In a crucial step of this pathway, cerebrospinal fluid (CSF) enters the brain via periarterial spaces. Previous studies in live mice have found that peristaltic waves in the arterial wall, driven by pulsatile blood flow, can induce the flow of CSF in the surrounding periarterial space. However, the exact mechanism driving CSF flow remains unclear among multiple possible contributing mechanisms. We developed a microfluidic device that serves as a two-dimensional model of the arterial wall interface between the periarterial space and inner artery to study the flow of peristaltically driven CSF. With this microfluidic model, we found that the induced flow oscillates with each pulsation of the peristaltic wave and travels in the same direction as the wave, with the bulk forward flow decreasing with higher frequency. We additionally found a promising power law relationship between the Root-Mean-Squared velocity of the induced flow and frequency. These observations contribute new insight to the understanding of CSF flow mechanisms.