Determination of the rheological properties of Matrigel for optimum seeding conditions in microfluidic cell cultures

K I W Kane,J Baller,R M T Fleming,S Hachi,E Lucumi Moreno,C M Lehr,C Wagner,R Dannert,R Sanctuary

doi:10.1063/1.5067382

Abstract

Hydrogels are increasingly used as a surrogate extracellular matrix in three-dimensional cell culture systems, including microfluidic cell culture. Matrigel is a hydrogel of natural origin widely used in cell culture, particularly in the culture of stem cell-derived cell lines. The use of Matrigel as a surrogate extracellular matrix in microfluidic systems is challenging due to its biochemical, biophysical, and biomechanical properties. Therefore, understanding and characterising these properties is a prerequisite for optimal use of Matrigel in microfluidic systems. We used rheological measurements and particle image velocimetry to characterise the fluid flow dynamics of liquefied Matrigel during loading into a three-dimensional microfluidic cell culture device. Using fluorescence microscopy and fluorescent beads for particle image velocimetry measurements (velocity profiles) in combination with classical rheological measurements of Matrigel (viscosity versus shear rate), we characterised the shear rates experienced by cells in a microfluidic device for three-dimensional cell culture. This study provides a better understanding of the mechanical stress experienced by cells, during seeding of a mixture of hydrogel and cells, into three-dimensional microfluidic cell culture devices.

Highlights

In vivo cellular microenvironmentIn a human soft tissue, all cells reside within a three-dimensional extracellular matrix, a viscous gel that mechanically strengthens the tissue and supports the cells within it
We characterised the rheological properties of a hydrogel (Matrigel) during a process representative of seeding a three-dimensional microfluidic cell culture device (OrganoPlate, Mimetas B.V.) with live cells
The Particle Image Velocimetry (PIV) measurements lead to the conclusion that the minimum amount of shear stress is obtained when the hydrogel is loaded at a temperature between 8◦C and 10◦C

Summary

Introduction

In vivo cellular microenvironmentIn a human soft tissue, all cells reside within a three-dimensional extracellular matrix, a viscous gel that mechanically strengthens the tissue and supports the cells within it. The extracellular matrix consists of a ground substance formed from large complex macromolecules, especially polysaccharides and proteoglycans, which attract water and ions, and fibrous proteins, especially collagen and elastin, which provide tensile strength and elasticity.[1,2] The cellular microenvironment consists of the extracellular matrix and the molecular species that can diffuse between cells and the microvasculature. The extracellular matrix permits free diffusion of molecules between cells and the microvasculature. It has a strong influence on cellular phenotype.[1] when attempting to mimic an in vivo microenvironment with an in vitro cell culture system, it is important to provide an appropriate surrogate extracellular matrix. An in vivo system refers to an experiment conducted within

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