Amorphous slicon dioxide (SiO2) is widely used as a food additive, in particular as anti-caking agent for powdered products, to clarify beverages, to control viscosity, as anti-foaming agent and dough modifier and to preserve color or durability. SiO2 particles are stable and have low toxicity, however, because of their recent use in the “nanoform”, the estimation of a health risk includes the study and the evaluation of new particle parameters, such as size, shape, surface charge and hydrophobicity and the exposure dose should be measured in terms of mass, total surface area and number of particles, or their combination. Nearly all nanoparticles (NPs) used in food products are toxic on cultured cells, SiO2 NPs for example, inhibit cell proliferation, induce cell death and act as pro-inflammatory and genotoxic agents. Even if these effects could not be important if the particles contained in consumer products do not reach metabolically active cells, however, since the information about the penetration of SiO2 NPs through the gastrointestinal track are still limited, information on the toxicity and safety of food additive silica NPs is urgently needed. In this study, four types of amorphous silica classified as A300, A380, T43 and T73, available on the market as additives for food and personal care products, were suspended in deionised water by following different dispersion procedures (mechanical stirring and ultrasound bath). The particles in suspension were size characterized through Differential Centrifugal Sedimentation (DCS), Sedimentation Field Flow Fractionation (SdFFF), SEM and TEM. Particle surface chemical characterization was performed by Particle-Induced X-ray Emission (PIXE) and X-ray Photoelectron Spectroscopy (XPS). To evaluate if the sizes play a role on the cell toxicity, the A380 and T43 suspensions were divided in two fractions; the size cut-offs were 190 nm and 270 nm respectively. The toxicity of all silica suspensions, “as are” and after a simulating acidic gastric digestion, was evaluated by using human intestinal Caco-2 cells as a model of the intestinal barrier. The results prove that the viability of the cells was preserved at around 85-90%, in all cases, independently of the particle sizes.
Physico-chemical characterization and in vitro assays on silica nano and micro-particles suitable for food and personal care applications
CONTADO, Catia;
2014
Abstract
Amorphous slicon dioxide (SiO2) is widely used as a food additive, in particular as anti-caking agent for powdered products, to clarify beverages, to control viscosity, as anti-foaming agent and dough modifier and to preserve color or durability. SiO2 particles are stable and have low toxicity, however, because of their recent use in the “nanoform”, the estimation of a health risk includes the study and the evaluation of new particle parameters, such as size, shape, surface charge and hydrophobicity and the exposure dose should be measured in terms of mass, total surface area and number of particles, or their combination. Nearly all nanoparticles (NPs) used in food products are toxic on cultured cells, SiO2 NPs for example, inhibit cell proliferation, induce cell death and act as pro-inflammatory and genotoxic agents. Even if these effects could not be important if the particles contained in consumer products do not reach metabolically active cells, however, since the information about the penetration of SiO2 NPs through the gastrointestinal track are still limited, information on the toxicity and safety of food additive silica NPs is urgently needed. In this study, four types of amorphous silica classified as A300, A380, T43 and T73, available on the market as additives for food and personal care products, were suspended in deionised water by following different dispersion procedures (mechanical stirring and ultrasound bath). The particles in suspension were size characterized through Differential Centrifugal Sedimentation (DCS), Sedimentation Field Flow Fractionation (SdFFF), SEM and TEM. Particle surface chemical characterization was performed by Particle-Induced X-ray Emission (PIXE) and X-ray Photoelectron Spectroscopy (XPS). To evaluate if the sizes play a role on the cell toxicity, the A380 and T43 suspensions were divided in two fractions; the size cut-offs were 190 nm and 270 nm respectively. The toxicity of all silica suspensions, “as are” and after a simulating acidic gastric digestion, was evaluated by using human intestinal Caco-2 cells as a model of the intestinal barrier. The results prove that the viability of the cells was preserved at around 85-90%, in all cases, independently of the particle sizes.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
