Introduction In addition to in situ measurements of small molecule permeability (Parts 1, 2 and 3), we wish to enable an assessment of permeability by sampling from the abluminal chamber of the µSiM in a manner similar to what is done with Transwells®-style devices. To begin this, we need to review the methods used with…
This is the third installment in a series of posts focused on the development of a method for measuring barrier permeability in the µSiM. In Part 1 we discussed the goal of making these measurements in situ at a position beneath the membrane. In Part 2 we validated this approach experimentally on the Andor Dragonfly…
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Note: a postscript regarding an assay to determine the activity of our MMP-2/MMP-9 inhibitor was added to this post on June 14, 2021. Introduction The blood-brain barrier (BBB) plays an important role in maintaining brain chemistry by restricting the permeability of small molecules and cells. Inflammatory diseases may disrupt the BBB and promote the development…
Introduction In a previous post, an initial version of the flow module and its sealing components were described. In order to improve the initial version based on collaborators’ feedback, several modifications have been made to simplify the device assembly for the end-user (Fig. 1) and address concerns about: 1) Local regions of high shear stress…
Introduction Static endothelial cell cultures have been routinely performed and optimized on the µSiM platform for multiple membrane and cell types. In order to increase the physiological relevance of our device with tissue vasculature mimetics, we need to incorporate fluid flow to emulate shear stresses experienced by endothelium under physiological circulatory conditions. Recently Mehran has…
Background Previously, we have demonstrated multiplexed digital sensing on MCP1, KC and TNFα secreted by RAW 264.7 cells stimulated in conventional cell culturing well plates. We observed decent TNFα and strong MCP1 response but no KC secretion from RAW cells upon 100ng/ml of LPS stimulation overnight. The work verified our platform’s capability of multiplex cytokine…
Introduction Mural cells, including smooth muscle cells and pericytes, are important for supporting endothelial cells in the vasculature [1]. They play a role in angiogenesis, and contribute to the development of the vascular basement membrane that provides structure for blood vessels [1,2]. Numerous in vitro models of the blood-brain barrier (BBB) have incorporated pericytes alongside…
Introduction Infection or injury of tissue results in inflammatory signalling that motivates leukocyte recruitment to an inflamed location. Monocytes in particular are implicated in both pro inflammatory signalling through the M1 macrophage phenotype and regulation through the M2 macrophage phenotype. The μSiM devices developed in our lab have yet to assess/optimize monocyte transmigration from the…