Toxicological evaluation of highly water dispersible few-layer graphene in vivo

Abstract

In the last decade, graphene-based materials have received increasing attention for both academic research and industrial uses. However, products containing graphene must meet the same standards for quality, safety and efficacy as products not containing nanomaterials. Our aim is to shed light on the toxicological characterization of few-layer graphene (FLG) dispersions. In the present study, graphene was easily dispersed in water using biocompatible riboflavin-5′-phosphate sodium salt (Rib). A highly concentrated FLG dispersion (G-Rib) was stable for months. G-Rib suspension was characterized by HR-TEM, Raman spectroscopy and ζ-potential. Our results showed that even at high concentration of G-Rib, cell survival was always above 85%. Then, we investigated the tissue distribution and toxic effects of G-Rib in mice up to 30 days after intravenous injections. Histological analysis of the tissues revealed hepatic accumulation and excretion through the kidneys. The biochemical and hematological parameters remained within the reference range showing no hematotoxicity. Finally, no signs of inflammation were detected in the cells isolated from the lymph nodes and spleen. The results of the study show that highly water dispersed FLG is a material with a very low toxic profile, which is one of the first requirements for the future development of biomedical applications.

Graphene‐Based Hybrid Functional Materials

“…[ 132,167 ] In these, water molecules can pass through the narrow hydrophobic channels formed by the unoxidized regions of GO. [ 168 ] The rejection of ions or bigger molecules takes place mainly for size exclusion as these cannot pass between the stacked GO flakes, yet anions can also be rejected by electrostatic interactions. [ 169 ] However, over time GO membranes tend to lose the semipermeability as a result of the increase in the interlayer spacing between flakes.…”

“…Many studies about the toxicity of graphene have been performed; still, notably different results have been reported, mainly because of the high diversity between the available graphene types, e.g., in size and chemical composition. [ 134b,168 ] Furthermore, the functionalization of graphene surface can greatly modify its toxicity. Pristine graphene is highly hydrophobic; thus, it has found limited application in the biomedical field.…”

How macrophages respond to two-dimensional materials: a critical overview focusing on toxicity

“…[55] We also found high cell viability of RAW 264.7 cells after exposure to FLG for 24 h and no in vivo hematotoxicity in Balb/c mice at 300 µg/mouse up to 30 days. [56] Recently, Cristo et al presented the detailed toxicity mechanism of low-dose (2.5 and 5 µg/cm 2 ) of 265 nm FLG in RAW 264.7 macrophages. The results of this study revealed that FLG induced inflammation by oxidative stress, triggering endoplasmic reticulum stress-mediated autophagy.…”

Eco-friendly and mechanochemically functionalised graphene with quick and high water dispersibility

“…34 Interestingly, FMN has the effect of reducing the toxicity profile of graphene, a serious concern with graphene use, 35,36 likely due to reduced graphene agglomeration which could further promote its use in biomedical devices. 37 With these properties in mind, a graphene was sought with the advantages of both liquid exfoliated graphene and ballmilled graphene, by ball-milling graphite in the presence of the surfactant FMN, followed by the removal of any non-covalently bonded FMN by dialysis. The FMN covalently bonded to graphene increased processability, while the synthesis is environmentally friendly and readily scalable.…”

“…34 Interestingly, FMN has the effect of reducing the toxicity profile of graphene, a serious concern with graphene use, 35,36 likely due to reduced graphene agglomeration which could further promote its use in biomedical devices. 37…”