Accessible Silicone Chip-to-Membrane Sealing Procedure for Flexible, Reliable Bonding

Organ-on-Chip platforms are a rapidly growing aspect of biomedical research. The expansion of this field has produced a range of different materials and methodologies for their construction and application. While the number of different devices - either provided commercially or developed in academia - continues to grow, a large step usually remains to be taken for new researchers entering the Organ-on-Chip field. One of the central issues in both novel and ongoing chip technologies remains producing a secure and leak-free sealing of chip devices. In this article, we provide a new path to chip development by presenting a chip sealing workflow that produces reliable water-tight connections between silicone chips and three culture membranes of different materials. The presented procedure is accessible for new chip development with limited input materials and provides an air-liquid interface (ALI) Organ-on-Chip. These chips are intended for cell culture fed through a porous membrane and apically exposed to air, such as in a Gut-, Skin-, or, as in the case presented here, Airway-on-Chip. We provide two different chip mold 3D designs, showing their binding to commercially available plastic membranes as well as porcine extracellular matrix (ECM) scaffolds. This Airway-on-Chip can be produced in-house; the different hurdles that may be encountered are presented here, and a showcase of their previous use as an Airway-on-Chip. This new sealing procedure involves vacuuming toluene-thinned Polydimethylsiloxane (PDMS) mortar to remove the toluene that leads to a thin and strong silicone coat embedded into the porous plastic or native ECM membrane surface. The second novelty of this procedure is the room temperature curing of the PDMS mortar to prevent disruption of the membranes due to differing thermal expansion in the materials being sealed together. This leads to a broadly applicable technique to bind the tested materials, producing multi-chambered PDMS chips with internalized culture membranes.