Existing models of Organ-on-a-Chip cost more to produce and have limited ability to functionally recapitulate human native tissues due to their limited incorporation of cell types. Researchers at Nationwide Children’s Hospital developed an improved model with their microfluidic Organ-on-a-chip fabrication based on 3D printing. This model optimizes and improves formulation of an extracellular matrix (ECM) that mimics the lamina propria (LP) to sustain the attachment and expansion of different cell types meaning this innovative model has cellular complexity that allows it to mimic human organs and replace animal models in various research settings.