Evaluation of the toxicity of food additive silica nanoparticles on gastrointestinal cells

J Appl Toxicol. 2014 Apr;34(4):424-35. doi: 10.1002/jat.2962. Epub 2013 Dec 3.


Silica nanoparticles (NPs) have been widely used in food products as an additive; however, their toxicity and safety to the human body and the environment still remain unclear. As a food additive, silica NPs firstly enter the human gastrointestinal tract along with food, thus their gastrointestinal toxicity deserves thorough study. Herein, we evaluated the toxicity of food additive silica NPs to cells originating from the gastrointestinal tract. Four silica NP samples were introduced to human gastric epithelial cell GES-1 and colorectal adenocarcinoma cell Caco-2 to investigate the effect of silica sample, exposure dose and exposure period on the morphology, viability and membrane integrity of cells. The cell uptake, cellular reactive oxygen species (ROS) level, cell cycle and apoptosis were determined to reveal the toxicity mechanism. The results indicate that all four silica NPs are safe for both GES-1 and Caco-2 cells after 24-h exposure at a concentration lower than 100 µg ml(-1) . At a higher concentration and longer exposure period, silica NPs do not induce the apoptosis/necrosis of cells, but arrest cell cycle and inhibit the cell growth. Notably, silica NPs do not pass through the Caco-2 cell monolayer after 4-h contact, indicating the low potential of silica NPs to cross the gastrointestinal tract in vivo. Our findings indicate that silica NPs could be used as a safe food additive, but more investigations, such as long-term in vivo exposure, are necessary in future studies.

Keywords: cytotoxicity; food additive; gastrointestinal cells; nanotoxicity; silica nanoparticles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Caco-2 Cells
  • Cell Cycle / drug effects
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Food Additives / chemistry
  • Food Additives / toxicity*
  • Humans
  • Microscopy, Electron, Transmission
  • Microscopy, Fluorescence
  • Nanoparticles / chemistry
  • Nanoparticles / toxicity*
  • Particle Size
  • Reactive Oxygen Species / metabolism
  • Silicon Dioxide / chemistry
  • Silicon Dioxide / toxicity*
  • Surface Properties


  • Food Additives
  • Reactive Oxygen Species
  • Silicon Dioxide