Figure 1.

Fabrication of vitrified collagen membrane and organ-on-a-chip device in which the membranes were integrated. (A) Vitrified collagen membranes were fabricated by depositing a neutralized collagen solution on a PDMS slab with defined rectangular shapes, which was subsequently dried in aseptic conditions. This resulted in a thin film of collagen along with salts and other phenol red. Following drying, the collagen film was washed with deionized water to remove salts and phenol red. After a second drying process, a thin film of collagen was obtained, which was easily handled and could be incorporated into the organ-on-a-chip device. (B) PDMS-based organ-on-a-chip device with exploded view (left) and assembled final device (right). The device contains a 1 mm² square microchannel (i), at the center of which the membrane (ii) was located. There is an open-top culture chamber (3 mm Ø) situated above the membrane (iii). PDMS layers were assembled by applying mortar to surfaces (blue, I and III) to sandwich the membrane in between. (C) Injection molding was used to eliminate the labor intensive fabrication procedure. (Left) Different layers of the device were assembled by incorporating the collagen I based membranes in between the channels held by magnets on each end. (Middle) Final assembled device consists of a PDMS-coated glass coverslip, a square microchannel, collagen-based membrane stretched in the center, and another square microchannel on top. (Right) The final assembled layer requires only plasma activation of surfaces to be attached to glass coverslip.