The Modular µSiM: A Mass Produced, Rapidly Assembled, and Reconfigurable Platform for the Study of Barrier Tissue Models In Vitro

Abstract

Advanced in vitro tissue chip models can reduce and replace animal experimentation and may eventually support “on‐chip” clinical trials. To realize this potential, however, tissue chip platforms must be both mass‐produced and reconfigurable to allow for customized design. To address these unmet needs, an extension of the µSiM (microdevice featuring a silicon‐nitride membrane) platform is introduced. The modular µSiM (m‐µSiM) uses mass‐produced components to enable rapid assembly and reconfiguration by laboratories without knowledge of microfabrication. The utility of the m‐µSiM is demonstrated by establishing an hiPSC‐derived blood–brain barrier (BBB) in bioengineering and nonengineering, brain barriers focused laboratories. In situ and sampling‐based assays of small molecule diffusion are developed and validated as a measure of barrier function. BBB properties show excellent interlaboratory agreement and match expectations from literature, validating the m‐µSiM as a platform for barrier models and demonstrating successful dissemination of components and protocols. The ability to quickly reconfigure the m‐µSiM for coculture and immune cell transmigration studies through addition of accessories and/or quick exchange of components is then demonstrated. Because the development of modified components and accessories is easily achieved, custom designs of the m‐µSiM shall be accessible to any laboratory desiring a barrier‐style tissue chip platform.

Modelling a Human Blood-Brain Barrier Co-Culture Using an Ultrathin Silicon Nitride Membrane-Based Microfluidic Device

“…Fixtures B1 and B2 were used to seal component 2 (bottom PSA channel with 150 µm heights and 50 µm thick cyclic olefin copolymer (COP) imaging layer) and component 1 with the membrane chip in it. In this study, we used a nanoporous silicon nitride (NPSN) membrane with 100 nm thickness, ~15% porosity, and ~50 nm pore size in both single-membrane [ 27 , 28 ] and double-membrane [ 30 ] chip formats. The single membrane chip format and the assembled µSiM are illustrated in Figure 3 A(ii,iii).…”

“…The assembled m-µSiM devices were further sterilised by UV light for 30 min to 1 h in the biosafety cabinet before using for cell culture. Step-by-step guides and tutorials can be found on the website: (accessed on 12 January 2023) and in a recent publication [ 30 ].…”

“…The µSiM has previously been used to set up various in vitro BBB models to study nanoparticle translocation with high-resolution in situ imaging [ 27 ] and immune cell trafficking [ 28 , 29 ]. The µSiM has been recently redesigned to enable a simple and rapid assembly from mass-produced components, eliminating the need for microfabrication tools [ 30 ]. Compared to the traditional hanging filter-based system, the flexible μSiM has a short distance from the objective to the cells, which, in combination with the ultra-thin membrane, allows high-resolution imaging in doubled layered co-culture setup.…”

Sourcing cells for in vitro models of human vascular barriers of inflammation

“…The model was further confirmed to mimic other key MS phenotypes, including disrupted tight junctions and increased interactions with immune cells, and opens the door for testing new drugs and therapeutic approaches ( 112 ). Further, our group recently incorporated EECM-BMEC-like cells into a tissue chip platform known as the modular-µSiM (m-µSiM) ( 66 ). m-µSiM culture was confirmed to mimic the baseline and inflammatory phenotypes of EECM-BMEC-like cells cultured in traditional culture plates and Transwell systems, and supported studies of both neutrophil and T cell TEM.…”

A computer vision approach for analyzing label free leukocyte trafficking dynamics on a microvascular mimetic

“…In our lab, we have developed the µSiM platform (27) as a modular microfluidic system that offers superior imaging quality for studying neutrophil transmigration in blood vasculature models (Figure 1A). The µSiM platform mitigates imaging issues found in conventional MPS platforms as it features optically clear (<100 nm thick) nanoporous silicon nitride (NPN) membranes separating apical and basal compartments of a simple microfluidic device (Figure 1B).…”