Toxicity of colloidal silica nanoparticles administered orally for 90 days in rats

Abstract

This study was undertaken to investigate the potential toxicity and establish the no observed adverse effect level (NOAEL) and target organ(s) of negatively charged colloidal silica particles of different sizes, ie, SiO 2 EN20(−) (20 nm) or SiO 2 EN100(−) 2(100 nm), administered by gavage in Sprague-Dawley rats. After verification of the physicochemical properties of the SiO 2 particles to be tested, a preliminary dose range-finding study and 90-day repeated dose study were conducted according to the Organisation for Economic Cooperation and Development test guideline. Based on the results of the 14-day dose range-finding study, a high dose was determined to be 2,000 mg/kg, and middle and low doses were set at 1,000 and 500 mg/kg, respectively. In the 90-day toxicity study, there were no animal deaths in relation to administration of SiO 2 particles of either size. In addition, no treatment-related clinical changes or histopathological findings were observed in any of the experimental groups. Moreover, no difference in toxic effects from chronic exposure to SiO 2 EN20(−) (20 nm) or SiO 2 EN100(−) (100 nm) was observed. The results of this study indicate that the NOAEL for SiO 2 EN20(−) and SiO 2 EN100(−) would most likely be 2,000 mg/kg, and no target organ was identified in rats of either sex.

An Evaluation of the in vivo Safety of Nonporous Silica Nanoparticles: Ocular Topical Administration versus Oral Administration

“…In contrast, Kim et al . 25 reported that high-dose oral intake (2000 mg/kg) of 20- and 100-nm SiNPs for 90 days appeared to be relatively safe in rats. The inconsistency in the aforementioned findings on the oral toxicity of SiNPs could be explained by the results of previous studies, which found that the nanotoxicity of SiNPs was dependent on their size and dose, as well as the cell type 13 , 26 .…”

Role of surface modification in zinc oxide nanoparticles and its toxicity assessment toward human dermal fibroblast cells

“…[69][70][71][72] The NPs used in our study were also found to be capable of producing intracellular ROS with increased lipid peroxide levels. The LPO produced more free radicals, which could damage biomolecules, such as DNA, proteins, and lipids in combination with ROS.…”

Nanoparticles in the Food Industry and Their Impact on Human Gut Microbiome and Diseases

“…SiO 2 NPs led to the destruction of the intestinal epithelial layer and liver fibrosis [ 6 , 65 ]. However, other studies showed SiO 2 NPs have no impact on the gut, deeming them safe for use in foods [ 66 , 67 ]. TiO 2 NP treatment led to the irregular arrangement of epithelial cells, increased length of intestinal villi, intestinal inflammation, and preneoplastic lesions [ 59 , 68 ].…”

“…By contrast, other studies have found silica to have no effect on the gut. Colloidal silica particles, differing in size (20 nm and 100 nm), were orally administered to Sprague-Dawley rats [ 66 ]. A ninety-day repeated dose (2000 mg/kg, 1000 mg/kg or 500 mg/kg) study was conducted.…”