Amorphous Silica NanoParticles (ASNP) can be synthetized via several processes, two of which are the thermal route (to yield pyrogenic silica) or the wet route from a solution containing silicate salts (to obtain precipitated, colloidal or mesoporous silica). Both methods of synthesis lead to ASNP that are applied as food additive (E551). Current food regulation does not require that production methods of additives are indicated on the product label, and, thus, the ASNP are listed without mentioning the production method. Recent results indicate, however, that pyrogenic ASNP are more cytotoxic than ASNP synthetized through the wet route. The present study was aimed at clarifying if two representative preparations of ASNP, NM-203 (pyrogenic) and NM-200 (precipitated), of comparable size, specific surface area, surface charge and hydrodynamic radius in complete growth medium, had different effects on two murine macrophage cell lines (MH-S and RAW264.7 cells). Our results show that, when incubated in protein-rich fluids, NM-203 adsorbed on their surface more proteins than precipitated NM-200 and, once incubated with macrophages, elicited a greater oxidative stress, assessed from Hmox1 induction and ROS production. Flow cytometry and helium ion microscopy indicated that pyrogenic NM-203 interacted with macrophages more strongly than the precipitated NM-200 and triggered a more evident inflammatory response, evaluated with Nos2 induction, NO production, and the secretion of TNF-α, IL-6 and IL-1β. Moreover, both ASNP synergized macrophage activation by bacterial lipopolysaccharide (LPS), with a higher effect observed for NM-203. In conclusion, the results presented here demonstrate that, compared to precipitated, pyrogenic ASNP exhibit enhanced interaction with serum proteins and cell membrane, and cause a larger oxidative stress and stronger pro-inflammatory effects in macrophages. Therefore, these two nanomaterials should not be considered biologically equivalent.
DI CRISTO Luisana;
MOVIA Dania;
BIANCHI Massimiliano G.;
ALLEGRI Manfredi;
MOHAMED Bashir M.;
BELL Alan P.;
MOORE Caroline;
PINELLI Silvana;
RASMUSSEN Kirsten;
RIEGO SINTES Juan;
PRINA-MELLO Adriele;
BUSSOLATI Ovidio;
BERGAMASCHI Enrico;
2015-12-21
OXFORD UNIV PRESS
JRC98514
1096-6080,
http://toxsci.oxfordjournals.org/content/150/1/40,
https://publications.jrc.ec.europa.eu/repository/handle/JRC98514,
10.1093/toxsci/kfv258,
