title: A Facile Method for Separating and Enriching Nano and Submicron Particles from Titanium Dioxide Found in Food and Pharmaceutical Products.
abstract: Recent studies indicate the presence of nano-scale titanium dioxide (TiO2) as an additive in human foodstuffs, but a practical protocol to isolate and separate nano-fractions from soluble foodstuffs as a source of material remains elusive. As such, we developed a method for separating the nano and submicron fractions found in commercial-grade TiO2 (E171) and E171 extracted from soluble foodstuffs and pharmaceutical products (e.g., chewing gum, pain reliever, and allergy medicine). Primary particle analysis of commercial-grade E171 indicated that 54% of particles were nano-sized (i.e., < 100 nm). Isolation and primary particle analysis of five consumer goods intended to be ingested revealed differences in the percent of nano-sized particles from 32%‒58%. Separation and enrichment of nano- and submicron-sized particles from commercial-grade E171 and E171 isolated from foodstuffs and pharmaceuticals was accomplished using rate-zonal centrifugation. Commercial-grade E171 was separated into nano- and submicron-enriched fractions consisting of a nano:submicron fraction of approximately 0.45:1 and 3.2:1, respectively. E171 extracted from gum had nano:submicron fractions of 1.4:1 and 0.19:1 for nano- and submicron-enriched, respectively. We show a difference in particle adhesion to the cell surface, which was found to be dependent on particle size and epithelial orientation. Finally, we provide evidence that E171 particles are not immediately cytotoxic to the Caco-2 human intestinal epithelium model. These data suggest that this separation method is appropriate for studies interested in isolating the nano-sized particle fraction taken directly from consumer products, in order to study separately the effects of nano and submicron particles.
authors: Molecular and Cellular Biosciences, School of Life Sciences, Arizona State University, Tempe AZ 85287-4501, United States of America.
authors: James J
authors: JJ
authors: Faust
authors: Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame IN, 46556, United States of America.
authors: Kyle
authors: http://orcid.org/0000-0003-1912-9819
authors: K
authors: Doudrick
authors: School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe AZ 85287-5306, United States of America.
authors: Yu
authors: Y
authors: Yang
authors: Molecular and Cellular Biosciences, School of Life Sciences, Arizona State University, Tempe AZ 85287-4501, United States of America.
authors: David G
authors: DG
authors: Capco
authors: School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe AZ 85287-5306, United States of America.
authors: Paul
authors: P
authors: Westerhoff
mesh_terms: D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival; D005591:Chemical Fractionation / Q000379:methods; D005503:Food Additives; D006801:Humans; D053768:Metal Nanoparticles / Q000648:ultrastructure; D010316:Particle Size; D004364:Pharmaceutical Preparations; D014025:Titanium
chemical_list: D005503:Food Additives; D004364:Pharmaceutical Preparations; C009495:titanium dioxide; D014025:Titanium