Understanding behavior and dissolution kinetics of ingested ENMs in simulated digestive fluids

I.S. Sohal, Y. Cho, K. Conca, K. Kensil, K. O’Fallon, D. Bello
University of Massachusetts-Lowell,
United States

Keywords: dissolution, food grade, ingested, nanomaterial, digestive fluid

Summary:

Engineered nanomaterials (ENMs) are used extensively in food as food additives, food packaging ingredients, as antimicrobials, for nutrient encapsulation and enhanced bioavailability, and as sensors for microorganism detection and identification. ENMs when ingested can potentially interact with cells/tissues of the gastrointestinal (GI) tract, especially the gastric and intestinal epithelial barrier, and induce a toxic response. In addition, complex fluids of the GI tract with their varying pH, ionic strength and enzymatic activity can influence the behavior and dissolution kinetics of ingested ENMs before they interact with the gastric or intestinal mucosa. A common in vitro approach for safety assessment of ingested ENMs (iENMs) involves exposing the gastric or intestinal epithelial cell lines directly to a specific dose range of iENMs without considering the physical and chemical transformation induced by their passage through the GI tract. Herein, we present a comprehensive study of the behavior and dissolution kinetics of 4 major iENMs in artificial saliva, gastric and intestinal fluids, as well as in a sequential digestion (saliva-gastric-intestinal) cascade with physiological relevance. Well-characterized iENM were introduced in a static dissolution model and systemic changes in morphology, size distribution and ion release were measured over time (up to 1hr in simulated saliva and 8hr in simulated gastric and intestinal fluids). In addition, the dissolution rate constants for each ENM were determined to understand their bio persistence and bio durability. We will present our findings on dissolution kinetics of ENMs in simulated digestive fluids independently, as well as in a sequential digestion model, and discuss their implications for in vitro safety assessment studies of iENMs.