Journal Article

An integrated methodology for assessing the impact of food matrix and gastrointestinal effects on the biokinetics and cellular toxicity of ingested engineered nanomaterials

Wang, Yanli, DeLoid, Glen M., White, Jason C., Demokritou, Philip, Lorente, Laura Rubio, Ericsson, Maria, De La Torre-Roche, Roberto, Pyrgiotakis, Georgios, Kapronezai, Klara, Xiao, Hang, McClements, David Julian, Zhang, Roujie, Konduru, Nagarjun V.

2017

Overview

Background Engineered nanomaterials (ENMs) are increasingly added to foods to improve their quality, sensory appeal, safety and shelf-life. Human exposure to these ingested ENMs (iENMS) is inevitable, yet little is known of their hazards. To assess potential hazards, efficient in vitro methodologies are needed to evaluate particle biokinetics and toxicity. These methodologies must account for interactions and transformations of iENMs in foods (food matrix effect) and in the gastrointestinal tract (GIT) that are likely to determine nano-biointeractions. Here we report the development and application of an integrated methodology consisting of three interconnected stages: 1) assessment of iENM-food interactions (food matrix effect) using model foods; 2) assessment of gastrointestinal transformations of the nano-enabled model foods using a three-stage GIT simulator; 3) assessment of iENMs biokinetics and cellular toxicity after exposure to simulated GIT conditions using a triculture cell model. As a case study, a model food (corn oil-in-water emulsion) was infused with Fe 2 O 3 (Iron(III) oxide or ferric oxide) ENMs and processed using this three-stage integrated platform to study the impact of food matrix and GIT effects on nanoparticle biokinetics and cytotoxicity . Methods A corn oil in phosphate buffer emulsion was prepared using a high speed blender and high pressure homogenizer. Iron oxide ENM was dispersed in water by sonication and combined with the food model. The resulting nano-enabled food was passed through a three stage (mouth, stomach and small intestine) GIT simulator. Size distributions of nano-enabled food model and digestae at each stage were analyzed by DLS and laser diffraction. TEM and confocal imaging were used to assess morphology of digestae at each phase. Dissolution of Fe2O3 ENM along the GIT was assessed by ICP-MS analysis of supernatants and pellets following centrifugation of digestae. An in vitro transwell triculture epithelial model was used to assess biokinetics and toxicity of ingested Fe 2 O 3 ENM. Translocation of Fe 2 O 3 ENM was determined by ICP-MS analysis of cell lysates and basolateral compartment fluid over time. Results It was demonstrated that the interactions of iENMs with food and GIT components influenced nanoparticle fate and transport, biokinetics and toxicological profile. Large differences in particle size, charge, and morphology were observed in the model food with and without Fe 2 O 3 and among digestae from different stages of the simulated GIT (mouth, stomach, and small intestine). Immunoflorescence and TEM imaging of the cell culture model revealed markers and morphology of small intestinal epithelium including enterocytes, goblet cells and M cells. Fe 2 O 3 was not toxic at concentrations tested in the digesta. In biokinetics studies, translocation of Fe 2 O 3 after 4 h was <1% and ~2% for digesta with and without serum, respectively, suggesting that use of serum proteins alters iENMs biokinetics and raises concerns about commonly-used approaches that neglect iENM – food-GIT interactions or dilute digestae in serum-containing media. Conclusions We present a simple integrated methodology for studying the biokinetics and toxicology of iENMs, which takes into consideration nanoparticle-food-GIT interactions. The importance of food matrix and GIT effects on biointeractions was demonstrated, as well as the incorporation of these critical factors into a cellular toxicity screening model. Standardized food models still need to be developed and used to assess the effect of the food matrix effects on the fate and bioactivity of iENMs since commercial foods vary considerably in their compositions and structures.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Administration, Oral / Bioavailability / Biocompatibility / Biological activity / Biomedical and Life Sciences / Biomedicine / Caco-2 Cells / Cell culture / Cell Survival - drug effects / Centrifugation / Corn / Corn oil / Culture media / Cytology / Cytotoxicity / Dietary supplements / Digestion / Drugs / Eating / Emulsions / Enterocytes / Environmental Health / Epithelium / Ferric Compounds - administration & dosage / Ferric Compounds - chemistry / Ferric Compounds - toxicity / Ferric oxide / Food / Food additives / Food matrix / Food products / Functional foods & nutraceuticals / Gastrointestinal system / Gastrointestinal tract / Gastrointestinal Tract - chemistry / Gastrointestinal Tract - drug effects / Gastrointestinal Tract - metabolism / Gastrointestinal Tract - pathology / Goblet cells / Hazard assessment / High pressure / Humans / iENM nanotoxicology / In vitro methods and tests / Ingested engineered nanomaterial / Intestine / Iron oxides / Lysates / M cells / Methodology / Methods / Models, Anatomic / Morphology / Nanomaterials / Nanoparticles / Nanosafety / Nanostructures - administration & dosage / Nanostructures - chemistry / Nanostructures - toxicity / Nanotechnology / Oils & fats / Pharmacology/Toxicology / Physiological aspects / Pneumology/Respiratory System / Proteins / Public Health / Reproducibility of Results / Risk Assessment / Sensory properties / Serum proteins / Shelf life / Small intestine / Solubility / Sonication / Stomach / Studies / Surface Properties / Time Factors / Toxicity testing / Toxicokinetics / Toxicology / Toxicology - methods / Translocation