title: Evaluation of the toxicity of food additive silica nanoparticles on gastrointestinal cells.
abstract: 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.
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai, 200444, China.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Yang
authors.forename: Zheng-Mei
authors.initials: ZM
authors.lastname: Song
authors.forename: Bin
authors.initials: B
authors.lastname: Cheng
authors.forename: Kun
authors.initials: K
authors.lastname: Xiang
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Chen
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Liu
authors.forename: Aoneng
authors.initials: A
authors.lastname: Cao
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuanfang
authors.initials: Y
authors.lastname: Liu
authors.forename: Haifang
authors.initials: H
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D018938:Caco-2 Cells; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005503:Food Additives / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry / Q000633:toxicity*; D013499:Surface Properties
chemical_list: D005503:Food Additives; D017382:Reactive Oxygen Species; D012822:Silicon Dioxide
keywords: cytotoxicity; food additive; gastrointestinal cells; nanotoxicity; silica nanoparticles