Organ-on-Chip (OoC) systems represent an emerging technique of 3D cell culture that is capable of bridging the gap between conventional 2D cell culture and animal models. OoC platforms typically consist of one or more compartments containing tissue-specific cells grown on a wide range of scaffolds such as membranes or hydrogels¹. The models are capable of mimicking one or more defined organotypic functions. Pumps enable continuous microfluidic perfusion of cell culture medium for removal of cellular waste products, supply with nutrition and growth factors for improved cellular differentiation, and recreating essential in vivo conditions. With the integration of immune cells, OoC systems can mimic human immune response in vitro². To date, a wide range of organs and functional units have been presented¹. These systems include models of the vasculature³, lung⁴, liver²^,⁵, and intestine⁶ that can be facilitated for drug testing⁵^,⁷ and infection studies⁶^,⁸.

We here present a human intestine-on-chip model integrating human epithelial cells forming an organotypic 3D topography of villus-like and crypt-like structures combined with an endothelial lining and tissue-resident macrophages. The model is cultured in a microfluidically perfused biochip in the format of a microscopic slide. Each biochip consists of two separate microfluidic cavities. Each cavity is divided by a porous polyethylene terephthalate (PET) membrane into an upper and lower chamber. The membrane itself also serves as the scaffold for the cells to grow on each side. The pores of the membrane enable cellular crosstalk and cell migration between cell layers. Each chamber can be accessed by two female luer lock-sized ports. Optionally, an additional mini-luer lock-sized port can provide access to the upper or lower chamber (Figure 1).

The OoC platform offers a number of readouts that can be obtained from a single experiment. The intestine-on-chip is tailored towards combining perfused 3D cell culture, effluent analysis, and fluorescence microscopy to assess cell marker expression, metabolization rates, immune response, microbial colonization and infection, and barrier function³^,⁶^,⁸. The model includes tissue-resident immune cells and direct contact of living microorganisms with the host tissue, which is a benefit compared to other published models⁹. Further, epithelial cells self-organize into three-dimensional structures that provide a physiologically relevant interface for the colonization with a living microbiota⁶.

Microfluidic Perfusion of HUVEC and C2BBe1 Cultured Biochips for Analyzing Immune Responses to Microbial Colonization