Cytotoxicity of Graphene Oxide and Graphene in Human Erythrocytes and Skin Fibroblasts

Abstract

Two-dimensional carbon-based nanomaterials, including graphene oxide and graphene, are potential candidates for biomedical applications such as sensors, cell labeling, bacterial inhibition, and drug delivery. Herein, we explore the biocompatibility of graphene-related materials with controlled physical and chemical properties. The size and extent of exfoliation of graphene oxide sheets was varied by sonication intensity and time. Graphene sheets were obtained from graphene oxide by a simple (hydrazine-free) hydrothermal route. The particle size, morphology, exfoliation extent, oxygen content, and surface charge of graphene oxide and graphene were characterized by wide-angle powder X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, dynamic light scattering, and zeta-potential. One method of toxicity assessment was based on measurement of the efflux of hemoglobin from suspended red blood cells. At the smallest size, graphene oxide showed the greatest hemolytic activity, whereas aggregated graphene sheets exhibited the lowest hemolytic activity. Coating graphene oxide with chitosan nearly eliminated hemolytic activity. Together, these results demonstrate that particle size, particulate state, and oxygen content/surface charge of graphene have a strong impact on biological/toxicological responses to red blood cells. In addition, the cytotoxicity of graphene oxide and graphene sheets was investigated by measuring mitochondrial activity in adherent human skin fibroblasts using two assays. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, a typical nanotoxicity assay, fails to predict the toxicity of graphene oxide and graphene toxicity because of the spontaneous reduction of MTT by graphene and graphene oxide, resulting in a false positive signal. However, appropriate alternate assessments, using the water-soluble tetrazolium salt (WST-8), trypan blue exclusion, and reactive oxygen species assay reveal that the compacted graphene sheets are more damaging to mammalian fibroblasts than the less densely packed graphene oxide. Clearly, the toxicity of graphene and graphene oxide depends on the exposure environment (i.e., whether or not aggregation occurs) and mode of interaction with cells (i.e., suspension versus adherent cell types).

Environmental applications using graphene composites: water remediation and gas adsorption

“…Liao and co-workers have shown that graphene oxide displays minimal cytotoxicity towards human erythrocytes and skin broblast cells, however graphite oxide and reduced graphene oxide were shown to inhibit cell growth. 229 These results agree well with the anti-bacterial properties observed for certain graphene materials. Additionally, cytotoxicities of graphene and graphene-based materials have also been tested in mice cell lines and have been shown to have negligible toxicity at low concentrations.…”

“…Multiple recent studies have focused on the use of graphene and graphene composites in biomedical applications. 133,[228][229][230][231] From these studies, as well as other cytotoxicity studies on graphene and related compounds, 69,232-251 we are able to draw some conclusions regarding graphene's biological toxicity.…”

“…250,251 Various in vitro toxicity studies have been conducted to determine the toxicity of graphene towards cancer [234][235][236][237][238] and human cell lines. 229,239 The cytotoxicity towards the cancer cell lines A549 was shown to depend largely on the cell culture medium components. 234,235 In particular it was noted that fetal bovine serum played a very important role, as it seems to coat the graphene sheets making them less toxic towards cell lines.…”

Graphene Oxide/Ag Nanoparticles Cooperated with Simvastatin as a High Sensitive X‐Ray Computed Tomography Imaging Agent for Diagnosis of Renal Dysfunctions

“…[11] The effect of simvastatin on hematotoxicity induced by GO/ AgNPs is a crucial indicator to evaluate therapy. [41,42] Herein, the effect of simvastatin to RBCs induced by GO/AgNPs was evaluated by the observation of optical microscopy and scanning electron microscopy (SEM) (Figure 3). As compared with the normal RBCs, the images of microscopy and SEM show the existence of damaged RBC after exposure to 1 mg per kg bw of GO/AgNPs.…”

Cytotoxicity of Group 5 Transition Metal Ditellurides (MTe2; M=V, Nb, Ta)

“…To study the materials' toxicity, A549 cells were exposed to the test materials and the remaining cell viabilities were measured using WST-8 assay.W ST-8, am itochondrial activity-based assay,w orks on the principle that soluble formazan is produced due to cellular reduction by dehydrogenase activities in viable cells. [10,[46][47][48] By normalising the absorbance intensities obtained with ac ontrols etup, where cells were not treated with any test materials, the extent of toxicity exhibited by the Group 5 ditellurides towards A549 cellsc ouldb ed etermined. Data collected from the WST-8 assay is illustrated in Figure 3.…”