Dynamics of Interstitial Fluid Pressure in Extracellular Matrix Hydrogels in Microfluidic Devices

Abstract

In order to understand how interstitial fluid pressure and flow affect cell behavior, many studies use microfluidic approaches to apply externally controlled pressures to the boundary of a cell-containing gel. It is generally assumed that the resulting interstitial pressure distribution quickly reaches a steady-state, but this assumption has not been rigorously tested. Here, we demonstrate experimentally and computationally that the interstitial fluid pressure within an extracellular matrix gel in a microfluidic device can, in some cases, react with a long time delay to external loading. Remarkably, the source of this delay is the slight (∼100 nm in the cases examined here) distension of the walls of the device under pressure. Finite-element models show that the dynamics of interstitial pressure can be described as an instantaneous jump, followed by axial and transverse diffusion, until the steady pressure distribution is reached. The dynamics follow scaling laws that enable estimation of a gel's poroelastic constants from time-resolved measurements of interstitial fluid pressure.

Luminal flow actuation generates coupled shear and strain in a microvessel-on-chip

“…The extensive characterization presented demonstrates the complexity of the mechanical behavior of hydrogel-based in vitro microvessels and the inherent coupling that exists among the different mechanical stresses in these systems. The current study, which complements previous work on the use of hydraulic pressure for deforming hydrogels [59][60][61], establishes luminal flow actuation as a novel mechanism for generating physiologically and pathologically relevant strain levels in hydrogel-based microfluidic systems. The extensive investigation of different parameters provides a detailed operating manual that we hope will facilitate the adoption of flow actuation in future in vitro platforms.…”

Poroelastic osmoregulation of living cell volume

“…Consider a thin layer of a poroelastic material attached from one side ( Figure S1 ) to a fixed substrate and immersed in a solvent for a long enough time to reach an equilibrium, that is, a state of homogeneity where C 0 and μ 0 are the initial concentration and chemical potential of solvent respectively. In the present study, the initial state is assumed to be isotropically swollen from the dry state ( Yoon et al, 2010 ; Yang et al., 2014 ; Tien et al, 2015 ; Malandrino and Moeendarbary, 2019 ). We consider the quasistatic deformation of an isotropic fully saturated poroelastic medium with a constant porosity.…”

Tissue culture on a chip: Developmental biology applications of self‐organized capillary networks in microfluidic devices

“…; Tien et al . ). To circumvent this connection problem, the Jeon group cultivated LFs and HUVECs in different positions on the device to facilitate the formation of openings between the self‐organized capillary meshwork and the PDMS channels (Fig.…”

“…Although several groups have successfully generated capillary networks in microfluidic devices, their meshwork usually does not have any connection to the PDMS channels (Hsu et al 2013a). Such devices are limited in their application, only allowing, for example, the effect of intestinal flow to be assayed (Tung et al 2013;Tien et al 2015). To Fig.…”