Abstract

Successful translation of in vivo experimental data to human patients is an unmet need and a bottleneck in the development of effective therapeutics. micro technology aims to address this need with significant advancements reported recently that enable modeling of organ level function. These microengineered chips enable researcher to recreate critical elements such as in vivo relevant tissue-tissue interface, air-liquid interface, and mechanical forces, such as mechanical stretch and fluidic shear stress, are crucial in emulating tissue level functions. Here, we present the development of a new, comprehensive 3D cell-culture system, where we combined our proprietary Organ-Chip technology with recent advantages in three-dimensional organotypic culture. Leveraging microfabrication techniques, we engineered a flexible chip that consists of a channel containing an organotypic epithelium surrounded by two vacuum channels that can be actuated to stretch the hydrogel throughout its thickness. Furthermore, the ceiling of this channel is a removable lid with a built-in microchannel that can be perfused with liquid or air and removed as needed for direct access to the tissue. The floor of this channel is a porous flexible membrane in contact with a microfluidic channel that provides diffusive mass transport to and from the channel. This additional microfluidic channel can be coated with endothelial cells to emulate a blood vessel and capture endothelial interactions. Our results show that the Open-Top Chip design successfully addresses common challenges associated with the Organs-on-Chips technology, including the capability to incorporate a tissue-specific extracellular matrix gel seeded with primary stromal cells, to reproduce the architectural complexity of tissues by micropatterning the gel, that can be extracted for H&E staining. We provide proof-of-concept data on the feasibility of the system using skin and alveolar epithelial primary cells and by simulating alveolar inflammation.