Table 1.

Knowledge Gaps on Mammalian Gastrointestinal Tract Digestive Parameters Modulating the Integrity, Surface Properties, and Absorption of Food‐Relevant Nanomaterials

Knowledge Gap Questions
Among physical forces, osmotic concentration, pH, digestive enzymes, other biochemicals, and commensal microbes, which GI luminal parameters are the strongest inducers of any changes observed in the size, shape, surface properties, and surface corona of NMs?
Is the size, shape, and surface properties of the full range of potentially food‐relevant NMs modified in the GI luminal milieu, or only certain categories of NMs?
What is the difference in percent absorption through the GI tract epithelium of NMs with different physicochemical properties?
Through which GI tract organs and epithelial cell subsets does the absorption of NMs of different chemical makeup occur?
What inherent properties of NMs of different chemical makeup determine their percent absorption through mucus and epithelial cells?
Does the percent absorption of a given NM differ from the mass‐balanced percent absorption of the bulk or ionic form of the same chemical?