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RISS 인기검색어
- 검색키워드
- 저자 : Vasuki Eppakayala (검색결과 4 건)
- 무료
- 기관 내 무료
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Green synthesis of graphene and its cytotoxic effects in human breast cancer cells
Gurunathan, Sangiliyandi,Han, Jae Woong,Eppakayala, Vasuki,Kim, Jin-Hoi Dove Medical Press 2013 International journal of nanomedicine Vol.8 No.-
<P><B>Background:</B></P><P>This paper describes an environmentally friendly (“green”) approach for the synthesis of soluble graphene using <I>Bacillus marisflavi</I> 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.</P><P><B>Methods:</B></P><P>The reduction of GO was characterized by ultraviolet–visible spectroscopy. Size distribution was analyzed by dynamic light scattering. Further, X-ray diffraction and high-resolution 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.</P><P><B>Results:</B></P><P>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.</P><P><B>Conclusion:</B></P><P>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.</P>
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Antibacterial activity of dithiothreitol reduced graphene oxide
Sangiliyandi Gurunathan,김진회,한재웅,아브달아메드,Vasuki Eppakayala,박미령,권득남 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.4
A green and simple approach is described for the large scale synthesis of reduced graphene oxide (rGO). The transition of graphene oxide (GO) into graphene was confirmed using various analytical techniques. Raman spectroscopy data indicate the partial removal of oxygen-containing functional groups from the surface of GO and formation of graphene. X-ray diffraction (XRD) was used to investigate the crystallinity of graphene nanosheets. The antibacterial activity of GO and rGO was evaluated using cell viability,reactive oxygen species (ROS) production and DNA fragmentation assays. The results suggest that GO and rGO possessed an excellent antimicrobial activity against Escherichia coli.
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Sangiliyandi Gurunathan,김진회,한재웅,Ahmed Abdal Dayem,Vasuki Eppakayala,박정현,조쌍구,이경진 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5
We described a green, cost effective and rapid method for synthesizing anisotropic AgNPs using a novel bacterium called Escherichia fergusoni. Furthermore, synthesized AgNPs were characterized by various analytical techniques. The present study demonstrates the efficiency of biologically synthesized AgNPs as a cytotoxic agent against MCF-7 cells and also this study investigates possible molecular mechanisms underlying the cytotoxic effects of AgNPs. AgNPs showed dose dependent cytotoxicity against MCF-7cells through activation of the lactate dehydrogenase (LDH), reactive oxygen species (ROS) generation and eventually leading to induction of apoptosis which was further confirmed through resulting nuclear fragmentation.
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<i>Ginkgo biloba</i> : a natural reducing agent for the synthesis of cytocompatible graphene
Gurunathan, Sangiliyandi,Han, Jae Woong,Park, Jung Hyun,Eppakayala, Vasuki,Kim, Jin-Hoi Dove Medical Press 2014 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.9 No.-
<P><B>Background</B></P><P>Graphene is a novel two-dimensional planar nanocomposite material consisting of rings of carbon atoms with a hexagonal lattice structure. Graphene exhibits unique physical, chemical, mechanical, electrical, elasticity, and cytocompatible properties that lead to many potential biomedical applications. Nevertheless, the water-insoluble property of graphene restricts its application in various aspects of biomedical fields. Therefore, the objective of this work was to find a novel biological approach for an efficient method to synthesize water-soluble and cytocompatible graphene using <I>Ginkgo biloba</I> extract (GbE) as a reducing and stabilizing agent. In addition, we investigated the biocompatibility effects of graphene in MDA-MB-231 human breast cancer cells.</P><P><B>Materials and methods</B></P><P>Synthesized graphene oxide (GO) and GbE-reduced GO (Gb-rGO) were characterized using various sequences of techniques: ultraviolet-visible (UV-vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy. Biocompatibility of GO and Gb-rGO was assessed in human breast cancer cells using a series of assays, including cell viability, apoptosis, and alkaline phosphatase (ALP) activity.</P><P><B>Results</B></P><P>The successful synthesis of graphene was confirmed by UV-vis spectroscopy and FTIR. DLS analysis was performed to determine the average size of GO and Gb-rGO. X-ray diffraction studies confirmed the crystalline nature of graphene. SEM was used to investigate the surface morphologies of GO and Gb-rGO. AFM was employed to investigate the morphologies of prepared graphene and the height profile of GO and Gb-rGO. The formation of defects in Gb-rGO was confirmed by Raman spectroscopy. The biocompatibility of the prepared GO and Gb-rGO was investigated using a water-soluble tetrazolium 8 assay on human breast cancer cells. GO exhibited a dose-dependent toxicity, whereas Gb-rGO-treated cells showed significant biocompatibility and increased ALP activity compared to GO.</P><P><B>Conclusion</B></P><P>In this work, a nontoxic natural reducing agent of GbE was used to prepare soluble graphene. The as-prepared Gb-rGO showed significant biocompatibility with human cancer cells. This simple, cost-effective, and green procedure offers an alternative route for large-scale production of rGO, and could be used for various biomedical applications, such as tissue engineering, drug delivery, biosensing, and molecular imaging.</P>
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