Physicochemical and toxicological evaluation of silica nanoparticles suitable for food and consumer products collected by following the EC recommendation.
Specific information about the particle size distribution, agglomeration state, morphology, and chemical composition of four silica samples, used as additives in food and in personal care products, were achieved with a combination of analytical techniques. The combined use of differential centrifugal sedimentation (DCS), sedimentation field flow fractionation (SdFFF), and scanning and transmission electron microscopy (SEM and TEM) allows to classify the water dispersed samples as "nanomaterials" according to the EC definition. The mechanical stirring and the ultrasound treatment were compared as dispersion methods. The particle surface chemical composition, determined by particle-induced X-ray emission (PIXE) and X-ray photoelectron spectroscopy (XPS), assessed the different levels of purity between the pyrogenic and the precipitated silica and highlighted particle surface chemical composition modifications in the outer shell when dispersed by mechanical stirring. The potential toxic effects of silica on intestinal Caco-2 cells were investigated using MTS assay and by measuring lactate dehydrogenase (LDH) release and caspases 3/7 activity after 24 h of incubation. No or limited decrease of cell viability was observed for all particles regardless of dispersion procedure, suggesting a relative innocuity of these silica samples.
Department of Chemical and Pharmaceutical Sciences, University of Ferrara, via L. Borsari, 46, 44121, Ferrara, Italy. catia.contado@unife.it.
Catia
C
Contado
Research Centre for the Physics of Matter and Radiation (PMR-LARN), Namur Nanosafety Center (NNC), NAmur Research Institute for LIfe Science (NARILIS), University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Jorge
J
Mejia
Research Centre for the Physics of Matter and Radiation (PMR-LARN), Namur Nanosafety Center (NNC), NAmur Research Institute for LIfe Science (NARILIS), University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Omar
O
Lozano García
Research Unit in Cellular Biology (URBC), NNC-NARILIS, University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Jean-Pascal
JP
Piret
Research Unit in Cellular Biology (URBC), NNC-NARILIS, University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Elise
E
Dumortier
Research Unit in Cellular Biology (URBC), NNC-NARILIS, University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Olivier
O
Toussaint
Research Centre for the Physics of Matter and Radiation (PMR-LARN), Namur Nanosafety Center (NNC), NAmur Research Institute for LIfe Science (NARILIS), University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Stéphane
S
Lucas
D018938:Caco-2 Cells; D002470:Cell Survival / Q000187:drug effects; D003358:Cosmetics / Q000737:chemistry* / Q000633:toxicity; D005503:Food Additives / Q000737:chemistry* / Q000633:toxicity; D031521:Fractionation, Field Flow; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D056951:Photoelectron Spectroscopy; D012822:Silicon Dioxide / Q000737:chemistry* / Q000633:toxicity
D003358:Cosmetics; D005503:Food Additives; D012822:Silicon Dioxide
Differential centrifugal sedimentation (DCS); Food additives; In vitro tests; Sedimentation field flow fractionation (SdFFF); Silica nanoparticles; Surface analysis