PROJECT SUMMARYNanomaterials are increasingly used in consumer products, processed food, and food packaging, and fewstudies have determined the consequences of nanoparticle ingestion. The ultimate goal of this work is todetermine if and how ingested metal oxide nanoparticles alter microorganism populations and intestinal function.A model of the GI tract and a panel of functional assays have been developed, and preliminary data shows thatdietary doses of pristine metal oxide nanoparticles decrease mineral, glucose, and lipid absorption. Thesedecreases in absorption are due to nanoparticle-induced alterations in microvilli structure. The presence of asingle species of beneficial bacteria in the model prevents changes in nutrient absorption following nanoparticleexposure, and early results suggest that nanoparticle reactivity with biological components is related to metaloxidation state. The central hypothesis is that the microbiota can detoxify ingested metal oxide nanomaterials,but high doses or chronic exposure can induce small intestinal dysbiosis, alter intestinal epithelial structure, andresult in decreased barrier properties and nutrient absorption. This hypothesis will be tested with three aims.First, individual strains of bacteria will be introduced into the GI tract model and molecular, functional, andstructural epithelial characteristics and microbial viability and genotoxicity affected by acute and chronic metaloxide nanoparticle exposure will be identified. Second, a mock community of upper GI bacteria will be engineeredand incorporated into the GI tract model to determine the effects of acute or chronic metal oxide nanoparticleexposure on microbial community dynamics and epithelial cell properties under both static and fluidic conditions.Third, a broiler chicken model (Gallus gallus), which is an established and robust method for quantifying nutrientbioavailability, brush border enzyme activity, and microbiome alterations will be used to validate in vitro results.This system, which will be the first to model upper GI conditions using a physiologically realistic, reproducible,high-throughput method with human-derived cells, will provide insight into nanoparticle-biological interactions.This valuable information is necessary for health and safety decisions and will be provided to both researchersand consumers. The scientific outcomes of this work are twofold: 1) the model created will allow quantitativeassessment of the contributions of bacteria toward GI health and function and the ability to determine how whatwe eat governs microbial dynamics; and 2) data collected will determine the overarching behavior of metal oxidenanoparticles with biological GI components and allow for extrapolation across a broad class of commonlyingested nanomaterials.