Facile Photopatterning of Perfusable Microchannels in Synthetic Hydrogels to Recreate Microphysiological Environments

Abstract

The fabrication of perfusable hydrogels is crucial for recreating in vitro microphysiological environments. Existing strategies to fabricate complex microchannels in hydrogels involve sophisticated equipment/techniques. We report a cost‐effective, facile, versatile, and ultra‐fast methodology to fabricate perfusable microchannels of complex shapes in photopolymerizable hydrogels without the need of specialized equipment or sophisticated protocols. Our methodology utilizes one‐step UV light‐triggered crosslinking and a photomask printed on inexpensive transparent films to photopattern PEG‐norbornene hydrogels. Complex and intricate patterns with high resolution, including perfusable microchannels, can be fabricated in <1 second. We integrate the perfusable hydrogel into a custom‐made microfluidic device that permits connection to external pump systems, allowing continuous fluid perfusion into the microchannels. Under dynamic culture, human endothelial cells form a functional and confluent endothelial monolayer that remains viable for at least 7 days and respond to inflammatory stimuli. Finally, we adapt our approach to photopattern norbornene hyaluronic acid hydrogels, highlighting the versatility of the technique. This study presents an innovative strategy to simplify and reduce the cost of biofabrication techniques for developing functional in vitro models using perfusable 3D hydrogels. Our approach offers a novel solution to overcome the complexities associated with existing methods, allowing engineering advanced in vitro microphysiological environments.This article is protected by copyright. All rights reserved

Tuneable hydrogel patterns in pillarless microfluidic devices

“…An added value of this treatment is the fact that it is possible to reproduce complex geometries using a simpler manufacturing method than photopatterning 40,43 with the ability to create a variety of designs, and, what's more, with total channel-to-channel contact that the phaseguide technique 38,39 containing a step does not give. With this surface treatment, it is possible to design more precise geometries that simulate more realistic tissues or histological structures, reproducing not only the shape but also the shear forces under flow conditions.…”

“…[33][34][35][36] Another pillar free design is the phaseguide technology which consists of meniscus pinning barriers, [37][38][39] but this technique does not allow the possibility of designing any geometry. Photopatternable hydrogels, [40][41][42][43] although representing a cutting-edge technology, present a challenge due to the complex development and manipulation required, despite their capability to achieve highly varied designs and geometries.…”

Measurement of covalent bond formation in light-curing hydrogels predicts physical stability under flow

“…Freestanding islands of gel were photopatterned inside a simple microfluidic flow cell (Fig 3a), following procedures previously described by us and others. 4,30 The chip was filled with fluorescently labeled polymer precursor solution, a photomask laid over the chip, and the precursor exposed through a 800 µm diameter pinhole. This simple photopatterning strategy made it straightforward to evaluate multiple exposure times on a single chip, by exposing one region, re-positioning the mask, re-exposing, and so on (Fig.…”

Mitigating reactive oxygen species production and increasing gel porosity improves lymphocyte motility and fibroblast spreading in photocrosslinked gelatin-thiol hydrogels

“…3,7,8 Similarly, cell-laden hydrogel constructs have been photopatterned with precise spatial and temporal control by lithography through a mask to mimic the complex architecture and local microenvironments of organs in vivo. [9][10][11] While studies have reported successful culture of encapsulated cell lines [12][13][14][15] and induced pluripotent stem cells [16][17][18] within photocrosslinked hydrogels and 3D printed scaffolds, there is also evidence of photoreaction-induced damage to a host of cell types. Exposure to ultraviolet radiation, photoinitiator and the highly reactive free radicals generated during photocrosslinking could damage plasma membranes, DNA and proteins, causing harm to cells and impairing cell viability.…”

“…3,7,8 Similarly, cell-laden hydrogel constructs have been photopatterned with precise spatial and temporal control by lithography through a mask to mimic the complex architecture and local microenvironments of organs in vivo. [9][10][11] (which was not certified by peer review) is the author/funder. All rights reserved.…”