GelPin Microphysiological Systems for 3D Neural Interfacing

The gut brain axis is a complex bi-directional communication pathway between the gastrointestinal tract, the enteric nervous system (ENS), and the central nervous system (CNS) that is implicated in not only gastrointestinal function but also cognitive tasks like memory and decision making. Gastrointestinal flora has also been implicated in alterations of brain function and behavior, however, mechanisms behind the gut-to-brain communication remain poorly understood. This is in part due to the availability and technical difficulty of innervating tissue engineered platforms. To investigate epithelial and neural interactions in the gastrointestinal tract and understand the impact of alterations in neural activity in response to intestinal contents, we are developing “Microphysiological Systems or Organ-Chips” inclusive of 3D hydrogels for neural-target tissue interfacing. Here I will discuss our laser-cut and assembly-based fabrication method for fast and cost-effective thermoplastic organ chips that include GelPins to enable interfacing cellular compartments of 3D hydrogels by harnessing the meniscus pinning effect.<br/><br/>It has also been proposed that seeding patient-derived cells will enable personalized medicine, but current models often utilize immortalized cells and rarely include support cells such as neurons. I will briefly discuss the inclusion of a patient-derived human epithelial monolayer from intestinal organoids for on-chip studies and methods to innervate our systems with enteric, autonomic, and central nervous system neural cells harnessing light-sensitive hydrogels and GelPins. Using these transparent, 3D cultures on-chip we can control and measure via video microscopy and quantitative image analysis modulation of cell function, such as calcium imaging of genetically modified enteric neurons or beat rate of biosensor cardiomyocytes (innervated by autonomic neurons). Our preliminary results show we are also able to support complex multi-cellular cultures of primary epithelial monolayers, microbiota, and an immune component via dendritic cells towards a better understanding of gut-to-brain signaling. Overall, our work indicates the ability to tailor the geometry of 3D microtissues on-chip to support diverse cell types, including neurons that extend and form functional synapses with target cells from visceral organ tissues. Ongoing work is focused on the inclusion of diseased phenotypes, neuromodulation and electrophysiology on-chip, characterization of the acute and chronic culture of neuronal populations, and multi-cellular chips for long-term evaluation. The combination of microphysiological systems with interfacing photocrosslinkable hydrogel compartments opens the door for further customization to recapitulate key features of innervated visceral organs at the bench.