Green and easy synthesis of biocompatible graphene for use as an anticoagulant

Han²,

Kim³

et al. 2015

IJN

158

129

Objective Graphene represents a monolayer or a few layers of sp 2 -bonded carbon atoms with a honeycomb lattice structure. Unique physical, chemical, and biological properties of graphene have attracted great interest in various fields including electronics, energy, material industry, and medicine, where it is used for tissue engineering and scaffolding, drug delivery, and as an antibacterial and anticancer agent. However, graphene cytotoxicity for ovarian cancer cells is still not fully investigated. The objective of this study was to synthesize graphene using a natural polyphenol compound resveratrol and to investigate its toxicity for ovarian cancer cells. Methods The successful reduction of graphene oxide (GO) to graphene was confirmed by UV-vis and Fourier transform infrared spectroscopy. Dynamic light scattering and scanning electron microscopy were employed to evaluate particle size and surface morphology of GO and resveratrol-reduced GO (RES-rGO). Raman spectroscopy was used to determine the removal of oxygen-containing functional groups from GO surface and to ensure the formation of graphene. We also performed a comprehensive analysis of GO and RES-rGO cytotoxicity by examining the morphology, viability, membrane integrity, activation of caspase-3, apoptosis, and alkaline phosphatase activity of ovarian cancer cells. Results The results also show that resveratrol effectively reduced GO to graphene and the properties of RES-rGO nanosheets were comparable to those of chemically reduced graphene. Biological experiments showed that GO and RES-rGO caused a dose-dependent membrane leakage and oxidative stress in cancer cells, and reduced their viability via apoptosis confirmed by the upregulation of apoptosis executioner caspase-3. Conclusion Our data demonstrate a single, simple green approach for the synthesis of highly water-dispersible functionalized graphene nanosheets, suggesting a possibility of replacing toxic hydrazine by a natural and safe phenolic compound resveratrol, which has similar efficacy in the reduction of GO to rGO. Resveratrol-based GO reduction would facilitate large-scale production of graphene-based materials for the emerging graphene-based technologies and biomedical applications.

Section: Notesmentioning

confidence: 99%

Reduction of graphene oxide by resveratrol: a novel and simple biological method for the synthesis of an effective anticancer nanotherapeutic molecule

Han²,

Kim³

et al. 2015

IJN

158

129

“…This obvious change in size distribution indicated that the biomass not only acted as a reducing agent to prepare the rGO but was also functionalized on the surface of the resulting rGO, leading to an increased Brownian motion rate after the reduction process. Wang et al 42 observed that after the reduction of GO with heparin, the average size of rGO layers was larger than that of GO. The rGO particles were formed by reducing GO nanosheets, which are about twice as large as GO nanosheets because of the aggregation of B-rGO fragments.…”

Section: Xrd Analysismentioning

confidence: 99%

“…Raman spectroscopy is highly sensitive to the electronic structure of a substance and has proven to be an essential tool for the characterization of carbon-based materials, especially C=C double bonds, which lead to high Raman intensities. 42 The common characteristics of carbon materials in Raman spectra are the G line (1580 cm −1 ) related to the first-order scattering of the E 2g phonons of sp 2 carbon atoms and the D line (1350 cm −1 ) as a breathing mode of k-point phonons of A 1g symmetry which is assigned to structural imperfections induced by the attachment of hyrodxyl and/or epoxide groups on the carbon surface. 19 Our results show that the G-and D-bands of GO appear at 1587 cm −1 and 1343 cm −1 , respectively ( Figure 6A).…”

Section: Raman Spectral Analysismentioning

confidence: 99%

“…Heparinfunctionalized rGO has been shown to have good stability in aqueous solution, owing to the strong electrostatic and steric repulsions of the heparin, which adsorb on the surfaces of rGO sheets. 42 Moreover, rGO has been shown to exhibit excellent biocompatibility and anticoagulant activity. 42 Hu et al 56 observed that human alveolar basal epithelial cells The effect of graphene oxide (GO) and bacterially reduced graphene oxide (B-rGO) on lactate dehydrogenase (LDH) activity in MCF-7 cells.…”

Section: Cell Mortalitymentioning

confidence: 99%

See 1 more Smart Citation

Green synthesis of graphene and its cytotoxic effects in human breast cancer cells

Han²,

Eppakayala³

et al. 2013

IJN

190

170

Background: This paper describes an environmentally friendly ("green") approach for the synthesis of soluble graphene using Bacillus marisflavi biomass as a reducing and stabilizing agent under mild conditions in aqueous solution. In addition, the study reported here investigated the cytotoxicity effects of graphene oxide (GO) and bacterially reduced graphene oxide (B-rGO) on the inhibition of cell viability, reactive oxygen species (ROS) generation, and membrane integrity in human breast cancer cells. Methods: The reduction of GO was characterized by ultraviolet-visible spectroscopy. Size distribution was analyzed by dynamic light scattering. Further, X-ray diffraction and highresolution scanning electron microscopy were used to investigate the crystallinity of graphene and the morphologies of prepared graphene, respectively. The formation of defects further supports the bio-functionalization of graphene, as indicated in the Raman spectrum of B-rGO. Surface morphology and the thickness of the GO and B-rGO were analyzed using atomic force microscopy, while the biocompatibility of GO and B-rGO were investigated using WST-8 assays on MCF-7 cells. Finally, cellular toxicity was evaluated by ROS generation and membrane integrity assays. Results:In this study, we demonstrated an environmentally friendly, cost-effective, and simple method for the preparation of water-soluble graphene using bacterial biomass. This reduction method avoids the use of toxic reagents such as hydrazine and hydrazine hydrate. The synthesized soluble graphene was confirmed using various analytical techniques. Our results suggest that both GO and B-rGO exhibit toxicity to MCF-7 cells in a dose-dependent manner, with a dose . 60 µg/mL exhibiting obvious cytotoxicity effects, such as decreasing cell viability, increasing ROS generation, and releasing of lactate dehydrogenase. Conclusion: We developed a green and a simple approach to produce graphene using bacterial biomass as a reducing and stabilizing agent. The proposed approach confers B-rGO with great potential for various biological and biomedical applications.

“…This obvious change in size distribution indicates that TEA not only acted as a reducing agent to prepare graphene, but it was also functionalized on the surfaces of the resulting rGO, leading to an increased Brownian motion rate after the reduction process. Wang et al 55 observed that after the reduction of GO with heparin, the average size of rGO was larger than GO. Liu et al 56 analyzed the size of various graphene based materials; among them GO nanosheets are the smallest in size.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Green chemistry approach for the synthesis of biocompatible graphene

Han²,

Kim³

2013

IJN

Background: Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. One of the most common methods for preparation of graphene is chemical exfoliation of graphite using powerful oxidizing agents. Generally, graphene is synthesized through deoxygenation of graphene oxide (GO) by using hydrazine, which is one of the most widespread and strongest reducing agents. Due to the high toxicity of hydrazine, it is not a promising reducing agent in large-scale production of graphene; therefore, this study focused on a green or sustainable synthesis of graphene and the biocompatibility of graphene in primary mouse embryonic fibroblast cells (PMEFs). Methods:Here, we demonstrated a simple, rapid, and green chemistry approach for the synthesis of reduced GO (rGO) from GO using triethylamine (TEA) as a reducing agent and stabilizing agent. The obtained TEA reduced GO (TEA-rGO) was characterized by ultraviolet (UV)-visible absorption spectroscopy, X-ray diffraction (XRD), particle size dynamic light scattering (DLS), scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). Results: The transition of graphene oxide to graphene was confirmed by UV-visible spectroscopy. XRD and SEM were used to investigate the crystallinity of graphene and the surface morphologies of prepared graphene respectively. The formation of defects further supports the functionalization of graphene as indicated in the Raman spectrum of TEA-rGO. Surface morphology and the thickness of the GO and TEA-rGO were analyzed using AFM. The presented results suggest that TEA-rGO shows significantly more biocompatibility with PMEFs cells than GO. Conclusion: This is the first report about using TEA as a reducing as well as a stabilizing agent for the preparation of biocompatible graphene. The proposed safe and green method offers substitute routes for large-scale production of graphene for several biomedical applications.