Intestinal absorption and biological effects of orally administered amorphous silica particles

Abstract

Although amorphous silica nanoparticles are widely used in the production of food products (e.g., as anticaking agents), there is little information available about their absorption and biological effects after oral exposure. Here, we examined the in vitro intestinal absorption and in vivo biological effects in mice of orally administered amorphous silica particles with diameters of 70, 300, and 1,000 nm (nSP70, mSP300, and mSP1000, respectively) and of nSP70 that had been surface-modified with carboxyl or amine groups (nSP70-C and nSP70-N, respectively). Analysis of intestinal absorption by means of the everted gut sac method combined with an inductively coupled plasma optical emission spectrometer showed that the intestinal absorption of nSP70-C was significantly greater than that of nSP70. The absorption of nSP70-N tended to be greater than that of nSP70; however, the results were not statistically significant. Our results indicate that silica nanoparticles can be absorbed through the intestine and that particle diameter and surface properties are major determinants of the degree of absorption. We also examined the biological effects of the silica particles after 28-day oral exposure in mice. Hematological, histopathological, and biochemical analyses showed no significant differences between control mice and mice treated with the silica particles, suggesting that the silica nanoparticles evaluated in this study are safe for use in food production.

Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine

“…Although changes in tissue viability could have been a limiting factor in this analysis, the viability/metabolic activity of intestinal tissue is routinely retained for &2 h under physiological conditions (Yoshida et al 2014) and so was not a confounding issue in these analyses.…”

“…Everted gut sac analysis was performed (Yoshida et al 2014) using small intestine isolated from fasted naïve Wistar rat. In brief, the small intestine was gently flushed with Krebs-Ringer buffer (KRB, pH 7.0) and then a 6-8 cm segment was removed and everted over a silicone tube.…”

Combined Action of Human Commensal Bacteria and Amorphous Silica Nanoparticles on the Viability and Immune Responses of Dendritic Cells

“…This choice of NP is based on the fact that the mean human adult intake of amorphous silica, which is used as a drug excipient or as a food additive and which is used for these purposes at concentrations ranging from 3 to 15 g/g of product (40), is estimated to be about 2 mg/kg of body weight/day (41). Although the nanosize nature of this material needs to be clarified (42), experiments suggest that SiO 2 NPs can enter intestinal epithelial cells and diffuse to the undermucosa or to the skin dermis (43)(44)(45)(46), where they may induce anaphylactic reactions (47,48). SiO 2 NPs are reported to induce cytotoxic, proinflammatory, and proimmune effects in murine DCs and skin Langerhans cells in vitro and in vivo (9,49,50).…”

Applications and Safety of Nanomaterials Used in the Food Industry

“…For example, on the basis of the results of a study using human gastric epithelial GES-1 cells and colorectal adenocarcinoma Caco-2 cells, Yang et al suggested that silica nanoparticles (200-450 nm) may arrest the cell cycle and inhibit cell growth but they do not induce apoptosis or necrosis 54) . We previously demonstrated that silicon was not detected in the liver or blood of mice after a 28-day daily oral exposure at a total dose of about 3.5 g silica particles/kg body weight, and that none of the particles tested showed toxic biological effects 36) .…”