Design of multicompartment organ-on-a-chip systems of the human endocervix capable of longitudinal time lapse imaging

• Kira Byers, Biomedical Engineering, University of Delaware

• Jason Gleghorn, Biomedical Engineering, University of Delaware

Design of multicompartment organ-on-a-chip systems of the human endocervix capable of longitudinal time lapse imaging

The vagina and cervix are largely understudied organs, especially in regard to sexually transmitted infection (STI) and the native immune response present from interactions with neighboring vascular cells and the extracellular matrix (ECM). We developed modular multicompartment organ-on-a-chip models to be used for time lapse imaging of a cell laden 3D collagen-I gel. The organ-on-a-chip, contains an “insert” (for cell culture outside the device) and “cassette” that clamps against the insert to create sealed fluidic channels. The insert consists of three layers of silicone. The top and bottom layers provide paths for fluid while the middle layer (ECM layer) allows for placement of a collagen-I gel, modeling the ECM. A dopamine coating was applied to the insert in order to functionalize the surface that is in contact with the gel, creating an adherent surface to polymerize directly in the insert. To test our proof-of-concept, NIH3T3 fibroblasts were incorporated within the collagen gel and polymerized in the insert. The cassette base material properties were selected to ensure compression/fluid seal within the insert and to reduce the distance from the embedded gel to the objective, therefore increasing the working distance. A peristaltic pump was used to perfuse culture medium across the embedded collagen-I gel. This continuous flow ran for multiple hours without leakage and without mixing of the top and bottom channels, proving that the compression of the cassette provided an appropriate fluid seal, and the gel retained integrity under flow conditions.