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Toxicity of Food Additive Silica Nanoparticles to Gastrointestinal Cells

Author: YangZuoXin
Tutor: WangHaiFang
School: Shanghai University
Course: Applied Chemistry
Keywords: Food additive Silica nanoparticles （nano-SiO2） Nano titanium dioxide（nano-TiO2） Gastrointestinal cells cytotoxicity
CLC: R114
Type: Master's thesis
Year: 2013
Downloads: 2
Quote: 0
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Abstract


Silica particles produced by aerosol and precipitation methods, have beenwidely applied in food products as additive. It is mainly used as an anticaking agentto maintain flow properties of powdered products. Along with the development ofsynthesis methods, silica particles become nano-sized. However, at present the safetystudies of silica nanoparticles （nano-SiO2） focus on the pulmonary toxicity in theview of occupational exposure, the safety data of nano-SiO2as food additive isscarce. Considering food additive nano-SiO2enters body along with food throughoral administration, and gastrointestinal tract will be the most important absorptionsite, a comprehensive study was performed to evaluate the toxicity of food additivenano-SiO2to gastrointestinal cells.Firstly, four food additive silica samples were purchased from differentcompanys with food additive licenses. A comprehensive characterization was givenby TEM, XRF, XRD, FT-IR, DLS and BET techniques. The four food additivenano-SiO2samples were amorphous and nano-sized, with a primary size of10-50nm. These particles had hydroxyl groups and negative charges on surface andaggreageted heavily in aqueous.Subsequently, a systematic sudy was performed on the toxicity of these four foodadditive nano-SiO2on two gastrointestinal cells, the human gastric epithelial cellGES-1and the human colorectal adenocarcinoma cell Caco-2. Generally, low doseof nano-SiO2was safe for human being. We found that nano-SiO2affected cellviabilities in a time-and dose-and sample-dependent manner. Although they did notresult in cell membrane damage, change the cell morphology, decrease themitochondrial membrane potential and increase apoptosis/necrosis of cells, they didenter cells, induce slight ROS generation, and inhibited the cell growth by blockingcells in S phase. The GES-1cells were more sensitive than the Caco-2cells to thesenano-SiO2. No translocation of nano-SiO2across Caco-2cell monolayer indicated it may be difficult for nano-SiO2to pass through the intestinal wall.In addition, the gastrointestinal toxicity of nano-TiO2particles separated fromgum was studied. We found that these nano-TiO2particles were safey under ourexperimental conditions.The results obtained in this thesis are essential for the biosafety assessment offood additives nanoparticles.

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