Toxicity studies of six types of carbon nanoparticles in a chicken-embryo model

Abstract

In the present study, the toxicity of six different types of carbon nanoparticles (CNPs) was investigated using a chicken-embryo model. Fertilized chicken eggs were divided into the following treatment groups: placebo, diamond NPs, graphite NPs, pristine graphene, small graphene oxide, large graphene oxide, and reduced graphene oxide. Experimental solutions at a concentration of 500 μg/mL were administrated into the egg albumin. Gross pathology and the rate of survival were examined after 5, 10, 15, and 20 days of incubation. After 20 days of incubation, blood samples were collected and the weight of the body and organs measured. The relative ratio of embryo survival decreased after treatment all treatments except diamond NPs. There was no correlation between the rate of survival and the ζ-potential or the surface charge of the CNPs in solution. Body and organ weight, red blood-cell morphology, blood serum biochemical parameters, and oxidative damage in the liver did not differ among the groups. These results indicate that CNPs can remain in blood circulation without any major side effects, suggesting their potential applicability as vehicles for drug delivery or active compounds per se. However, there is a need for further investigation of their properties, which vary depending on production methods and surface functionalization.

Keywords: diamond; graphene; graphite; nanoparticles; oxidative stress; red blood cells; surface charge; toxicity.

Figure 1

Nanoparticles were visualized using transmission electron microscopy (A, C, E, G, I, K) and a digital camera (B, D, F, H, J, L). Note: Nanoparticles of diamond (A, B), graphite (C, D), pristine graphene (E, F), small graphene oxide (G, H), large graphene oxide (I, J), and reduced graphene oxide (K, L).

Figure 2

Room-temperature Fourier transform infrared spectra. Note: Nanoparticles of diamond (A), graphite (B), pristine graphene (C), small graphene oxide (D), large graphene oxide (E), and reduced graphene oxide (F).

Figure 3

Chicken-embryo development after 10 (A), 15 (B), and 20 (C) days of incubation. Abbreviations: DNPs, diamond nanoparticles; GNPs, graphite nanoparticles; pG, pristine graphene; sGO, small graphene oxide; lGO, large graphene oxide; rGO, reduced graphene oxide.

Figure 4

Red blood-cell morphology by light microscopy. Note: Placebo (A) and nanoparticles of diamond (B), graphite (C), pristine graphene (D), small graphene oxide (E), large graphene oxide (F), and reduced graphene oxide (G).

Figure 5

Concentration of malondialdehyde (MDA) in chicken-embryo liver lysate (nmol/mg protein). Notes: Data are presented as averages of multiple determinations (n=4), with error bars representing standard deviation. Differences were not significant (P>0.05). Abbreviations: Pl, placebo; DNPs, diamond nanoparticles; GNPs, graphite nanoparticles; pG, pristine graphene; sGO, small graphene oxide; lGO, large graphene oxide; rGO, reduced graphene oxide.