AUTHOR=Ambrosone Alfredo , Scotto di Vettimo Maria Rosaria , Malvindi Maria Ada , Roopin Modi , Levy Oren , Marchesano Valentina , Pompa Pier Paolo , Tortiglione Claudia , Tino Angela 

TITLE=Impact of Amorphous SiO2 Nanoparticles on a Living Organism: Morphological, Behavioral, and Molecular Biology Implications

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=2

YEAR=2014

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2014.00037

DOI=10.3389/fbioe.2014.00037

ISSN=2296-4185

ABSTRACT=<p>It is generally accepted that silica (SiO<sub>2</sub>) is not toxic. But the increasing use of silica nanoparticles (SiO<sub>2</sub>NPs) in many different industrial fields has prompted the careful investigation of their toxicity in biological systems. In this report, we describe the effects elicited by SiO<sub>2</sub>NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles, 25 nM in diameter, were administered to living <italic>Hydra vulgaris</italic> (Cnidaria). The dose-related effects were defined by morphological and behavioral assays. The results revealed an all-or-nothing lethal toxicity with a rather high threshold (35 nM NPs) and a LT50 of 38 h. At sub lethal doses, the morphophysiological effects included: animal morphology alterations, paralysis of the gastric region, disorganization and depletion of tentacle specialized cells, increase of apoptotic and collapsed cells, and reduction of the epithelial cell proliferation rate. Transcriptome analysis (RNAseq) revealed 45 differentially expressed genes, mostly involved in stress response and cuticle renovation. Our results show that <italic>Hydra</italic> reacts to SiO<sub>2</sub>NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO<sub>2</sub>NPs, and that the physiological modifications are transduced to gene expression modulation.</p>