Computer-Controlled Microcirculatory Support System for Endothelial Cell Culture and Shearing

TLDR

Endothelial cells lining blood vessels are continuously exposed to hemodynamic shear stress, which alters their morphology and biological activity. This paper introduces a self‑contained microcirculatory culture system designed to efficiently study shear‑stress effects on endothelial cell alignment and elongation in vitro. The system integrates elastomeric microfluidic chambers with computer‑controlled piezoelectric pins on a refreshable Braille display, variable‑rate flow through channel design, and on‑chip valving and pumping that allow primary endothelial cell seeding and differential shearing across multiple compartments. Microfluidic flows induced significant alignment and elongation of endothelial cells in the flow direction proportional to shear stress, and the system surpasses previous microfluidic and macroscopic setups by providing higher flow rates and enabling convenient parallel studies of endothelial responses.

Abstract

Endothelial cells (ECs) lining the inner lumen of blood vessels are continuously subjected to hemodynamic shear stress, which is known to modify EC morphology and biological activity. This paper describes a self-contained microcirculatory EC culture system that efficiently studies such effects of shear stress on EC alignment and elongation in vitro. The culture system is composed of elastomeric microfluidic cell shearing chambers interfaced with computer-controlled movement of piezoelectric pins on a refreshable Braille display. The flow rate is varied by design of channels that allow for movement of different volumes of fluid per variable-speed pump stroke. The integrated microfluidic valving and pumping system allowed primary EC seeding and differential shearing in multiple compartments to be performed on a single chip. The microfluidic flows caused ECs to align and elongate significantly in the direction of flow according to their exposed levels of shear stress. This microfluidic system overcomes the small flow rates and the inefficiencies of previously described microfluidic and macroscopic systems respectively to conveniently perform parallel studies of EC response to shear stress.