Cytotoxicity Effects of Graphene and Single-Wall Carbon Nanotubes in Neural Phaeochromocytoma-Derived PC12 Cells
ABSTRACT Graphitic nanomaterials such as graphene layers (G) and single-wall carbon nanotubes (SWCNT) are potential candidates in a large number of biomedical applications. However, little is known about the effects of these nanomaterials on biological systems. Here we show that the shape of these materials is directly related to their induced cellular toxicity. Both G and SWCNT induce cytotoxic effects, and these effects are concentration- and shape-dependent. Interestingly, at low concentrations, G induced stronger metabolic activity than SWCNT, a trend that reversed at higher concentrations. Lactate dehydrogenase levels were found to be significantly higher for SWCNT as compared to the G samples. Moreover, reactive oxygen species were generated in a concentration- and time-dependent manner after exposure to G, indicating an oxidative stress mechanism. Furthermore, time-dependent caspase 3 activation after exposure to G (10 microg/mL) shows evidence of apoptosis. Altogether these studies suggest different biological activities of the graphitic nanomaterials, with the shape playing a primary role.
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ABSTRACT: Graphene nanoplatelets with lateral dimensions of 50–200 nm and thicknesses <2 nm were utilized for the extraction of nucleic acids (NAs) from eukaryotic and prokaryotic cells. The graphene nanoplatelets (both chemically exfoliated graphene oxide nanoplatelets and hydrazine-reduced graphene oxide nanoplatelets) successfully extracted plasmid DNA (pDNA) from Escherichia coli bacteria, comparable to a conventional phenol–chloroform (PC) method. Furthermore, it was found that the yield of graphene nanoplatelets in genomic DNA (gDNA) and RNA extractions from embryonic stem cells (ESCs) was also comparable to the yield of the conventional methods. The effects of the graphene nanoplatelets on restriction enzyme digestion of the pDNA and gene amplification of all the extracted NAs (including pDNA, gDNA and RNA) were also investigated in order to confirm the quality of the extractions. These results not only demonstrated an easy gene extraction capability of graphene nanoplatelets with a high gene amplification, but also provide an easy, fast, inexpensive and biocompatible DNA/RNA extraction method.RSC Advances 11/2014; 4(105). DOI:10.1039/C4RA11458B · 3.71 Impact Factor
Applied Surface Science 01/2014; 320:596-601. · 2.54 Impact Factor
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ABSTRACT: We have revealed a connection between DNA-nanoparticle (NP) binding and in vitro DNA damage induced by citrate- and branched polyethylenimine-coated silver nanoparticles (c-AgNPs and b-AgNPs) as well as graphene oxide (GO) nanosheets. All three types of nanostructures triggered an early onset of DNA melting, where the extent of the melting point shift depended upon both the type and concentration of the NPs. Specifically, at a DNA/NP weight ratio of 1.1/1, the melting temperature of lambda DNA dropped from 94°C down to 76°C, 60°C and room temperature for GO, c-AgNPs and b-AgNPs, respectively. Consistently, dynamic light scattering revealed that the largest changes in DNA hydrodynamic size were also associated with the binding of b-AgNPs. Upon introduction to cells, b-AgNPs also exhibited the highest cytotoxicity, at the half-maximal inhibitory (IC50) concentrations of 3.2, 2.9 and 5.2 mg/L for B and T-lymphocyte cell lines and primary lymphocytes, compared to the values of 13.4, 12.2 and 12.5 mg/L for c-AgNPs and 331, 251 and 120 mg/L for GO nanosheets, respectively. At cytotoxic concentrations, all NPs elicited elevated genotoxicities via increased number of micronuclei in the lymphocyte cells. However, b-AgNPs also induced micronuclei at subtoxic concentrations starting from 0.1 mg/L, likely due to their stronger cellular adhesion and internalization, as well as their subsequent interference with normal DNA synthesis or chromosome segregation during the cell cycle. This study facilitates our understanding of the effects of NP chemical composition, surface charge and morphology on DNA stability and genotoxicity, with implications ranging from nanotoxicology to nanobiotechnology and nanomedicine.Chemical Research in Toxicology 03/2015; DOI:10.1021/acs.chemrestox.5b00052 · 4.19 Impact Factor