Assessment of the In Vivo Toxicity of Gold Nanoparticles

Abstract

The environmental impact of nanoparticles is evident; however, their toxicity due to their nanosize is rarely discussed. Gold nanoparticles (GNPs) may serve as a promising model to address the size-dependent biological response to nanoparticles because they show good biocompatibility and their size can be controlled with great precision during their chemical synthesis. Naked GNPs ranging from 3 to 100 nm were injected intraperitoneally into BALB/C mice at a dose of 8 mg/kg/week. GNPs of 3, 5, 50, and 100 nm did not show harmful effects; however, GNPs ranging from 8 to 37 nm induced severe sickness in mice. Mice injected with GNPs in this range showed fatigue, loss of appetite, change of fur color, and weight loss. Starting from day 14, mice in this group exhibited a camel-like back and crooked spine. The majority of mice in these groups died within 21 days. Injection of 5 and 3 nm GNPs, however, did not induce sickness or lethality in mice. Pathological examination of the major organs of the mice in the diseased groups indicated an increase of Kupffer cells in the liver, loss of structural integrity in the lungs, and diffusion of white pulp in the spleen. The pathological abnormality was associated with the presence of gold particles at the diseased sites, which were verified by ex vivo Coherent anti-Stoke Raman scattering microscopy. Modifying the surface of the GNPs by incorporating immunogenic peptides ameliorated their toxicity. This reduction in the toxicity is associated with an increase in the ability to induce antibody response. The toxicity of GNPs may be a fundamental determinant of the environmental toxicity of nanoparticles.

On Biodecorated Gold Nanoparticles Distributed within Tissues and Cells

“…Similar results were obtained for 3 nm AuNPs, 5nm, 5, 12, 20, 30, 50, and 70nm, 3, 5, 8, 12, 17, 37, 50, and 1200nm, 4 and 13nm, and 40nm 112 [53][54][55][56][57][58]. Taking into account the abovementioned data, it could be possible to expand the boundaries to both the lower level (to 3 nm) and larger particles up to 100 nm to avoid a toxic AuNP effect, if we are considering a limited dose of about 10 12 particles/ml.…”

Microscopic Analysis of the Interaction of Gold Nanoparticles with Cells of the Innate Immune System

“…Although both the in vivo and in vitro testing of AuNPs of different sizes are known to sometimes produce contradictory results 17,18 , we first focused on the 35 nm AuNPs as an example for microscopic detection since this size is easier to examine. Our method was based on correlating the signals of the transmitted high energy electrons and the scattered low energy ones coming mainly from the surface.…”

Gold nanoparticles in cancer therapy

“…In the literature, AuNPs have been reported to lack the ability to induce adverse and acute toxicity [17] and are thus deemed to be biocompatible entities for use in biomedical applications [17,18] . However, recent studies have shown that there could be more to AuNP toxicity than already surmised and that the extent of toxicity response is closely associated with the size of the AuNPs [19,20] . Investigations have revealed that decreasing the size of NPs correlated with more widespread tissue distribution, heightened potential to deeper penetration within certain tissues, more effective internalization by cells, and increased toxic effects [21] .…”