Impact of Amorphous SiO₂Nanoparticles on a Living Organism: Morphological, Behavioral, and Molecular Biology Implications

Abstract

It is generally accepted that silica (SiO2) is not toxic. But the increasing use of silica nanoparticles (SiO2NPs) 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 SiO2NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles, 25 nM in diameter, were administered to living Hydra vulgaris (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 Hydra reacts to SiO2NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO2NPs, and that the physiological modifications are transduced to gene expression modulation.

An Integrated Multilevel Analysis Profiling Biosafety and Toxicity Induced by Indium- and Cadmium-Based Quantum Dots in Vivo

“…To study the interactions of QDs with Hydra, living polyps were exposed to different concentrations of QDs (from 25 nM to 100 nM) in their culture medium. This range of concentration was selected on the basis of our previous works carried out with different types of nanocrystals [24][25][26][27]30 . After 24 h the animals were thoroughly rinsed to remove QDs that adhere to the external epithelium and inspected by fluorescence microscopy.…”

Proposing Urothelial and Muscle In Vitro Cell Models as a Novel Approach for Assessment of Long-Term Toxicity of Nanoparticles

“…This is in agreement with the observed larger aggregation of NPs in physiological media that hinders NPs internalization. More generally, amorphous SiO 2 NPs were shown in many studies to be nontoxic [ 68 ], but due to many different types of SiO 2 NPs, their toxicity depends upon the physicochemical characteristics of the particles [ 59 , 69 ], and the response against SiO 2 NPs varies in cell-dependent manner [ 70 , 71 , 72 ]. There are not many long-term studies examining the effect of SiO 2 NPs.…”

The engineered nanoparticles in food chain: potential toxicity and effects

“…Despite these changes, Ambrosone et al emphasized that SiO 2 NPs not caused lethal toxicity. Authors considered that Hydra is able to adapt to high doses of SiO 2 NPs and adjust its homeostasis [141]. , ion-regulatory (plasma sodium (Naþ), potassium (Kþ) and chloride (Cl) levels and Naþ/Kþ) and enzymological (ATPase activity in gill) parameters in the tested group.…”