GS Institute of Bio and Nanotechnology

Coimbatore, India

GS Institute of Bio and Nanotechnology

Coimbatore, India

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Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology
Journal of Industrial and Engineering Chemistry | Year: 2015

This study was aimed at investigating the toxicological effects of GO on beneficial Bacillus soil microbes. Five bacterial isolates screened from the rhizosphere of a common pulse-growing agricultural field were identified as Bacillus marisflavi, Bacillus cereus, Bacillus subtilis, Bacillus megaterium, and Bacillus mycoides. To study the effect of GO under in vitro conditions, GO was prepared and characterized by various analytical techniques. Our results suggest that GO decreases cell viability in a concentration- and time-dependent manner by regulating biochemical changes and demonstrate that GO nanoparticles can negatively impact beneficial bacterial communities in the soil. © 2015 The Korean Society of Industrial and Engineering Chemistry.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology
Arabian Journal of Chemistry | Year: 2014

Emergence of antibiotic resistance has become an increasingly important public health issue. Although several new antibiotics have been developed in the last few decades, none of them show improved activity against multidrug-resistant bacteria. Silver nanoparticles (AgNPs) have long been known for their broad-spectrum antibacterial effects. The development of a rapid, dependable, simple, cost-effective, biocompatible, and environmentally friendly method to synthesize nanoparticles is an essential aspect of current biomedical research. This paper describes the extracellular biochemical synthesis of AgNPs using supernatants from . Bacillus cereus cultures and characterization of the synthesized AgNPs, using several analytical techniques. The nanoparticles showed a maximum absorbance at 420. nm in ultraviolet-visible spectra. Particle size analysis by dynamic light scattering and transmission electron microscopy revealed the formation of homogeneous and well-dispersed nanoparticles with an average size of 10. nm. We investigated the dose-dependent antibacterial activity of AgNPs against . Escherichia fergusonii and . Streptococcus mutans. In addition, the efficiency of AgNPs with various broad-spectrum antibiotics against these test strains was evaluated. The results show that the combination of antibiotics with AgNPs has significant antimicrobial effects. The greatest enhancement was observed with gentamycin and vancomycin against . E. fergusonii and . S. mutans, respectively. This work supports that AgNPs can be used to enhance the activity of existing antibiotics against Gram-negative and Gram-positive bacteria. © 2014 The Author.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Han J.W.,Konkuk University | Kwon D.-N.,Konkuk University | Kim J.-H.,Konkuk University
Nanoscale Research Letters | Year: 2014

Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases. © 2014 Gurunathan et al.; licensee Springer.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Han J.W.,Konkuk University | Park J.H.,Konkuk University | Kim J.H.,Konkuk University
International Journal of Nanomedicine | Year: 2014

Background: Recently, graphene and graphene-related materials have attracted much attention due their unique properties, such as their physical, chemical, and biocompatibility properties. This study aimed to deter mine the cytotoxic effects of graphene oxide (GO) that is reduced biologically using Ganoderma spp. mushroom extracts in MDA-MB-231 human breast cancer cells. Methods: Herein, we describe a facile and green method for the reduction of GO using extracts of Ganoderma spp. as a reducing agent. GO was reduced without any hazardous chemicals in an aqueous solution, and the reduced GO was characterized using a range of analytical procedures. The Ganoderma extract (GE)-reduced GO (GE-rGO) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, dynamic light scattering, scanning electron microscopy, Raman spectroscopy, and atomic force microscopy. Furthermore, the toxicity of GE-rGO was evaluated using a sequence of assays such as cell viability, lactate dehydrogenase leakage, and reactive oxygen species generation in human breast cancer cells (MDA-MB-231). Results: The preliminary characterization of reduction of GO was confirmed by the red-shifting of the absorption peak for GE-rGO to 265 nm from 230 nm. The size of GO and GE-rGO was found to be 1,880 and 3,200 nm, respectively. X-ray diffraction results confirmed that reduction processes of GO and the processes of removing intercalated water molecules and the oxide groups. The surface functionalities and chemical natures of GO and GE-rGO were confirmed using Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface morphologies of the synthesized graphene were analyzed using high-resolution scanning electron microscopy. Raman spectroscopy revealed single- and multilayer properties of GE-rGO. Atomic force microscopy images provided evidence for the formation of graphene. Furthermore, the effect of GO and GE-rGO was examined using a series of assays, such as cell viability, membrane integrity, and reactive oxygen species generation, which are key molecules involved in apoptosis. The results obtained from cell viability and lactate dehydrogenase assay suggest that GO and GE-rGO cause dose-dependent toxicity in the cells. Interestingly, it was found that biologically derived GE-rGO is more toxic to cancer cells than GO. Conclusion: We describe a simple, green, nontoxic, and cost-effective approach to producing graphene using mushroom extract as a reducing and stabilizing agent. The proposed method could enable synthesis of graphene with potential biological and biomedical applications such as in cancer and angiogenic disorders. To our knowledge, this is the frst report using mushroom extract as a reducing agent for the synthesis of graphene. Mushroom extract can be used as a biocatalyst for the production of graphene. © 2014 Gurunathan et al.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology
Journal of Industrial and Engineering Chemistry | Year: 2015

Here we report a simple, fast, cost-effective, and nonpolluting approach for synthesis of silver nanoparticles (AgNPs) using leaf extract of Typha angustifolia. We demonstrate the dose-dependent antibacterial activity of AgNPs and different antibiotics against Escherichia coli and Klebsiella pneumoniae. Furthermore, we demonstrate the efficacy of AgNPs in combination with various broad-spectrum antibiotics against E. coli and K. pneumoniae. The results show that combinations of antibiotics and AgNPs show significant antimicrobial effects at sub-lethal concentrations of the antibiotics. These data suggest that combinations of antibiotics and AgNPs can be used therapeutically for the treatment of infectious diseases. © 2015 The Korean Society of Industrial and Engineering Chemistry.


Han J.W.,Konkuk University | Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Jeong J.-K.,Konkuk University | And 4 more authors.
Nanoscale Research Letters | Year: 2014

The goal of the present study was to investigate the toxicity of biologically prepared small size of silver nanoparticles in human lung epithelial adenocarcinoma cells A549. Herein, we describe a facile method for the synthesis of silver nanoparticles by treating the supernatant from a culture of Escherichia coli with silver nitrate. The formation of silver nanoparticles was characterized using various analytical techniques. The results from UV-visible (UV-vis) spectroscopy and X-ray diffraction analysis show a characteristic strong resonance centered at 420 nm and a single crystalline nature, respectively. Fourier transform infrared spectroscopy confirmed the possible bio-molecules responsible for the reduction of silver from silver nitrate into nanoparticles. The particle size analyzer and transmission electron microscopy results suggest that silver nanoparticles are spherical in shape with an average diameter of 15 nm. The results derived from in vitro studies showed a concentration-dependent decrease in cell viability when A549 cells were exposed to silver nanoparticles. This decrease in cell viability corresponded to increased leakage of lactate dehydrogenase (LDH), increased intracellular reactive oxygen species generation (ROS), and decreased mitochondrial transmembrane potential (MTP). Furthermore, uptake and intracellular localization of silver nanoparticles were observed and were accompanied by accumulation of autophagosomes and autolysosomes in A549 cells. The results indicate that silver nanoparticles play a significant role in apoptosis. Interestingly, biologically synthesized silver nanoparticles showed more potent cytotoxicity at the concentrations tested compared to that shown by chemically synthesized silver nanoparticles. Therefore, our results demonstrated that human lung epithelial A549 cells could provide a valuable model to assess the cytotoxicity of silver nanoparticles. © 2014, Han et al.; licensee Springer.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Han J.W.,Konkuk University | Park J.H.,Konkuk University | Kim J.-H.,Konkuk University
Nanoscale Research Letters | Year: 2014

Gold nanoparticles (AuNPs) are a fascinating class of nanomaterial that can be used for a wide range of biomedical applications, including bio-imaging, lateral flow assays, environmental detection and purification, data storage, drug delivery, biomarkers, catalysis, chemical sensors, and DNA detection. Biological synthesis of nanoparticles appears to be simple, cost-effective, non-toxic, and easy to use for controlling size, shape, and stability, which is unlike the chemically synthesized nanoparticles. The aim of this study was to synthesize homogeneous AuNPs using pharmaceutically important Ganoderma spp. We developed a simple, non-toxic, and green method for water-soluble AuNP synthesis by treating gold (III) chloride trihydrate (HAuCl4) with a hot aqueous extract of the Ganoderma spp. mycelia. The formation of biologically synthesized AuNPs (bio-AuNPs) was characterized by ultraviolet (UV)-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the biocompatibility of as-prepared AuNPs was evaluated using a series of assays, such as cell viability, lactate dehydrogenase leakage, and reactive oxygen species generation (ROS) in human breast cancer cells (MDA-MB-231). The color change of the solution from yellow to reddish pink and strong surface plasmon resonance were observed at 520 nm using UV-visible spectroscopy, and that indicated the formation of AuNPs. DLS analysis revealed the size distribution of AuNPs in liquid solution, and the average size of AuNPs was 20 nm. The size and morphology of AuNPs were investigated using TEM. The biocompatibility effect of as-prepared AuNPs was investigated in MDA-MB-231 breast cancer cells by using various concentrations of AuNPs (10 to 100 μM) for 24 h. Our findings suggest that AuNPs are non-cytotoxic and biocompatible. To the best of our knowledge, this is the first report to describe the synthesis of monodispersed, biocompatible, and soluble AuNPs with an average size of 20 nm using Ganoderma spp. This study opens up new possibilities of using an inexpensive and non-toxic mushroom extract as a reducing and stabilizing agent for the synthesis of size-controlled, large-scale, biocompatible, and monodispersed AuNPs, which may have future diagnostic and therapeutic applications. © 2014 Gurunathan et al.; licensee Springer.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Woong Han J.,Konkuk University | Kim E.,Konkuk University | And 3 more authors.
Journal of Nanobiotechnology | Year: 2014

Background: Graphene is the 2D form of carbon that exists as a single layer of atoms arranged in a honeycomb lattice and has attracted great interest in the last decade in view of its physical, chemical, electrical, elastic, thermal, and biocompatible properties. The objective of this study was to synthesize an environmentally friendly and simple methodology for the preparation of graphene using a recombinant enhanced green fluorescent protein (EGFP).Results: The successful reduction of GO to graphene was confirmed using UV-vis spectroscopy, and FT-IR. DLS and SEM were employed to demonstrate the particle size and surface morphology of GO and EGFP-rGO. The results from Raman spectroscopy suggest the removal of oxygen-containing functional groups from the surface of GO and formation of graphene with defects. The biocompatibility analysis of GO and EGFP-rGO in human embryonic kidney (HEK) 293 cells suggests that GO induces significant concentration-dependent cell toxicity in HEK cells, whereas graphene exerts no adverse effects on HEK cells even at a higher concentration (100 μg/mL).Conclusions: Altogether, our findings suggest that recombinant EGFP can be used as a reducing and stabilizing agent for the preparation of biocompatible graphene. The novelty and originality of this work is that it describes a safe, simple, and environmentally friendly method for the production of graphene using recombinant enhanced green fluorescent protein. Furthermore, the synthesized graphene shows excellent biocompatibility with HEK cells; therefore, biologically synthesized graphene can be used for biomedical applications. To the best of our knowledge, this is the first and novel report describing the synthesis of graphene using recombinant EGFP. © 2014 Gurunathan et al.; licensee BioMed Central Ltd.


Gurunathan S.,Konkuk University | Gurunathan S.,GS Institute of Bio and Nanotechnology | Jeong J.-K.,Konkuk University | Han J.W.,Konkuk University | And 3 more authors.
Nanoscale Research Letters | Year: 2015

Silver nanoparticles (AgNPs) are prominent group of nanomaterials and are recognized for their diverse applications in various health sectors. This study aimed to synthesize the AgNPs using the leaf extract of Artemisia princeps as a bio-reductant. Furthermore, we evaluated the multidimensional effect of the biologically synthesized AgNPs in Helicobacter pylori, Helicobacter felis, and human lung (L132) and lung carcinoma (A549) cells. UV-visible (UV–vis) spectroscopy confirmed the synthesis of AgNPs. X-ray diffraction (XRD) indicated that the AgNPs are specifically indexed to a crystal structure. The results from Fourier transform infrared spectroscopy (FTIR) indicate that biomolecules are involved in the synthesis and stabilization of AgNPs. Dynamic light scattering (DLS) studies showed the average size distribution of the particle between 10 and 40 nm, and transmission electron microscopy (TEM) confirmed that the AgNPs were significantly well separated and spherical with an average size of 20 nm. AgNPs caused dose-dependent decrease in cell viability and biofilm formation and increase in reactive oxygen species (ROS) generation and DNA fragmentation in H. pylori and H. felis. Furthermore, AgNPs induced mitochondrial-mediated apoptosis in A549 cells; conversely, AgNPs had no significant effects on L132 cells. The results from this study suggest that AgNPs could cause cell-specific apoptosis in mammalian cells. Our findings demonstrate that this environmentally friendly method for the synthesis of AgNPs and that the prepared AgNPs have multidimensional effects such as anti-bacterial and anti-biofilm activity against H. pylori and H. felis and also cytotoxic effects against human cancer cells. This report describes comprehensively the effects of AgNPs on bacteria and mammalian cells. We believe that biologically synthesized AgNPs will open a new avenue towards various biotechnological and biomedical applications in the near future. © 2015, Gurunathan et al.; licensee Springer.

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