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Sample records for extended graphene nanomaterials

  1. Graphene-based nanomaterials and their electrochemistry.

    PubMed

    Pumera, Martin

    2010-11-01

    Graphene-based nanomaterials are in the forefront of chemical research. This tutorial review provides an introduction to their electrochemistry, its fundamentals and applications. Selected examples of applications in energy storage and sensing are presented. The synthetic methods for preparing graphenes as well as their materials chemistry are thoroughly discussed, as they have a profound influence on the electronic and electrochemical behavior of graphene-related nanomaterials. Inherent electrochemistry and spectroelectrochemistry of graphene nanomaterials is discussed thoroughly. Important application in sensing and energy storage areas are highlighted.

  2. Graphene-based nanomaterials for bioimaging.

    PubMed

    Lin, Jing; Chen, Xiaoyuan; Huang, Peng

    2016-10-01

    Graphene-based nanomaterials, due to their unique physicochemical properties, versatile surface functionalization, ultra-high surface area, and good biocompatibility, have attracted considerable interest in biomedical applications such as biosensors, drug delivery, bioimaging, theranostics, and so on. In this review, we will summarize the current advances in bioimaging of graphene-based nanomaterials, including graphene, graphene oxide (GO), reduced graphene oxide (rGO), graphene quantum dots (GQDs), and their derivatives. There are two methods to synthesize graphene-based nanomaterials: in situ synthesis and binding method. We will highlight the molecular imaging modalities including optical imaging (fluorescence (FL), two-photon FL, and Raman imaging), PET/SPECT (positron emission tomography/single photon emission computed tomography), MRI (magnetic resonance imaging), PAI (photoacoustic imaging), CT (computed tomography), and multimodal imaging. In the end, we will elaborate on the prospects and challenges of their future bioimaging applications.

  3. Graphene-related nanomaterials: tuning properties by functionalization

    NASA Astrophysics Data System (ADS)

    Tang, Qing; Zhou, Zhen; Chen, Zhongfang

    2013-05-01

    In this review, we discuss the most recent progress on graphene-related nanomaterials, including doped graphene and derived graphene nanoribbons, graphene oxide, graphane, fluorographene, graphyne, graphdiyne, and porous graphene, from both experimental and theoretical perspectives, and emphasize tuning their stability, electronic and magnetic properties by chemical functionalization.

  4. Recent developments of phototherapy based on graphene family nanomaterials.

    PubMed

    Zhang, Baomei; Wang, Yang; Liu, Jiyong; Zhai, Guangxi

    2016-10-19

    Graphene-based nanomaterials have drawn abundant interest in various fields such as biomedicine in recent years, thanks to their unique physico-chemical properties. Due to the ultra-high surface area of single-layered graphene, higher molecular loading is obtained. In addition, easy modifications are acquired because of its ample oxygen-content functional groups. Based on the above talking advantages, graphene-based nanomaterials have been widely explored as novel nano-vectors for disease theranostics. In this article, we give a comprehensive review about graphene-based nanomaterials, including introduction about different members of graphene family nanomaterials (GFNs), various modifications, toxicity and biomedical applications of graphene-based derivatives. More attentions are given to phototherapy application in this paper. The mechanisms of photothermal and photodynamic therapy are also offered. Finally, the prospects and challenges of the graphene-based nanomaterials are discussed in this review. That this review article will provide a comprehensive understanding of graphene-based nanomaterials is the pursuit.

  5. Surface engineering of graphene-based nanomaterials for biomedical applications.

    PubMed

    Shi, Sixiang; Chen, Feng; Ehlerding, Emily B; Cai, Weibo

    2014-09-17

    Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications.

  6. Surface Engineering of Graphene-Based Nanomaterials for Biomedical Applications

    PubMed Central

    2015-01-01

    Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications. PMID:25117569

  7. Deposition of graphene nanomaterial aerosols in human upper airways.

    PubMed

    Su, Wei-Chung; Ku, Bon Ki; Kulkarni, Pramod; Cheng, Yung Sung

    2016-01-01

    Graphene nanomaterials have attracted wide attention in recent years on their application to state-of-the-art technology due to their outstanding physical properties. On the other hand, the nanotoxicity of graphene materials also has rapidly become a serious concern especially in occupational health. Graphene naomaterials inevitably could become airborne in the workplace during manufacturing processes. The inhalation and subsequent deposition of graphene nanomaterial aerosols in the human respiratory tract could potentially result in adverse health effects to exposed workers. Therefore, investigating the deposition of graphene nanomaterial aerosols in the human airways is an indispensable component of an integral approach to graphene occupational health. For this reason, this study carried out a series of airway replica deposition experiments to obtain original experimental data for graphene aerosol airway deposition. In this study, graphene aerosols were generated, size classified, and delivered into human airway replicas (nasal and oral-to-lung airways). The deposition fraction and deposition efficiency of graphene aerosol in the airway replicas were obtained by a novel experimental approach. The experimental results acquired showed that the fractional deposition of graphene aerosols in airway sections studied were all less than 4%, and the deposition efficiency in each airway section was generally lower than 0.03. These results indicate that the majority of the graphene nanomaterial aerosols inhaled into the human respiratory tract could easily penetrate through the head airways as well as the upper part of the tracheobronchial airways and then transit down to the lower lung airways, where undesired biological responses might be induced.

  8. Bioapplications of graphene constructed functional nanomaterials.

    PubMed

    Gulzar, Arif; Yang, Piaoping; He, Fei; Xu, Jiating; Yang, Dan; Xu, Liangge; Jan, Mohammad Omar

    2017-01-25

    Graphene has distinctive mechanical, electronic, and optical properties, which researchers have applied to develop innovative electronic materials including transparent conductors and ultrafast transistors. Lately, the understanding of various chemical properties of graphene has expedited its application in high-performance devices that generate and store energy. Graphene is now increasing its terrain outside electronic and chemical applications toward biomedical areas such as precise bio sensing through graphene-quenched fluorescence, graphene-enhanced cell differentiation and growth, and graphene-assisted laser desorption/ionization for mass spectrometry. In this Account, we evaluate recent efforts to apply graphene and graphene oxides (GO) to biomedical research and a few different approaches to prepare graphene materials designed for biomedical applications and a brief perspective on their future applications. Because of its outstanding aqueous processability, amphiphilicity, surface functionalizability, surface enhanced Raman scattering (SERS), and fluorescence quenching ability, GO chemically exfoliated from oxidized graphite is considered a promising material for biological applications. In addition, the hydrophobicity and flexibility of large-area graphene synthesized by chemical vapor deposition (CVD) allow this material to play an important role in cell growth and differentiation. Graphene is considered to be an encouraging and smart candidate for numerous biomedical applications such as NIR-responsive cancer therapy and fluorescence bio-imaging and drug delivery. To that end, suitable preparation and unique approaches to utilize graphene-based materials such as graphene oxides (GOs), reduced graphene oxides (rGOs), and graphene quantum dots (GQDs) in biology and medical science are gaining growing interest. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Carbon nanomaterials in biosensors: should you use nanotubes or graphene?

    PubMed

    Yang, Wenrong; Ratinac, Kyle R; Ringer, Simon P; Thordarson, Pall; Gooding, J Justin; Braet, Filip

    2010-03-15

    From diagnosis of life-threatening diseases to detection of biological agents in warfare or terrorist attacks, biosensors are becoming a critical part of modern life. Many recent biosensors have incorporated carbon nanotubes as sensing elements, while a growing body of work has begun to do the same with the emergent nanomaterial graphene, which is effectively an unrolled nanotube. With this widespread use of carbon nanomaterials in biosensors, it is timely to assess how this trend is contributing to the science and applications of biosensors. This Review explores these issues by presenting the latest advances in electrochemical, electrical, and optical biosensors that use carbon nanotubes and graphene, and critically compares the performance of the two carbon allotropes in this application. Ultimately, carbon nanomaterials, although still to meet key challenges in fabrication and handling, have a bright future as biosensors.

  10. Sunlight-induced Transformations of Graphene-based Nanomaterials in Aquatic Environments

    EPA Science Inventory

    Graphene-based nanomaterials and other related carbon nanomaterials (CNMs) can be released from products during their life cycles. Upon entry into aquatic environments, they are potentially transformed by photochemical reactions, oxidation reactions and biological processes, all ...

  11. Sunlight-induced Transformations of Graphene-based Nanomaterials in Aquatic Environments

    EPA Science Inventory

    Graphene-based nanomaterials and other related carbon nanomaterials (CNMs) can be released from products during their life cycles. Upon entry into aquatic environments, they are potentially transformed by photochemical reactions, oxidation reactions and biological processes, all ...

  12. Interaction of Radiation with Graphene Based Nanomaterials for Sensing Fissile Materials

    DTIC Science & Technology

    2016-03-01

    Interaction of Radiation with Graphene Based Nanomaterials for Sensing Fissile Materials Distribution Statement A. Approved for public release...University, West Lafayette IN 47907 Grant#: HDTRA1-09-1-0047 Young Investigator Award “ Interaction of Radiation with Graphene Based Nanomaterials...impact on the development of human resources? What is the impact on physical, institutional, and information resources that form infrastructure? What

  13. Aggregation, Deposition and Release of Graphene Oxide Nanomaterials in the Aquatic Environment

    EPA Science Inventory

    Graphene is an atomically thin two dimensional carbon-based nanomaterial that is composed of a single layer of sp2 – hybridized carbon atoms as found in graphite.1, 2 Usage of graphene-based nanomaterials is increasing rapidly and these materials are predicted to be the most abun...

  14. Aggregation, Deposition and Release of Graphene Oxide Nanomaterials in the Aquatic Environment

    EPA Science Inventory

    Graphene is an atomically thin two dimensional carbon-based nanomaterial that is composed of a single layer of sp2 – hybridized carbon atoms as found in graphite.1, 2 Usage of graphene-based nanomaterials is increasing rapidly and these materials are predicted to be the most abun...

  15. Applications and toxicity of graphene family nanomaterials and their composites

    PubMed Central

    Singh, Zorawar

    2016-01-01

    Graphene has attracted much attention of scientific community due to its enormous potential in different fields, including medical sciences, agriculture, food safety, cancer research, and tissue engineering. The potential for widespread human exposure raises safety concerns about graphene and its derivatives, referred to as graphene family nanomaterials (GFNs). Due to their unique chemical and physical properties, graphene and its derivatives have found important places in their respective application fields, yet they are being found to have cytotoxic and genotoxic effects too. Since the discovery of graphene, a number of researches are being conducted to find out the toxic potential of GFNs to different cell and animal models, finding their suitability for being used in new and varied innovative fields. This paper presents a systematic review of the research done on GFNs and gives an insight into the mode and action of these nanosized moieties. The paper also emphasizes on the recent and up-to-date developments in research on GFNs and their nanocomposites for their toxic effects. PMID:27051278

  16. Biological interactions of graphene-family nanomaterials: an interdisciplinary review.

    PubMed

    Sanchez, Vanesa C; Jachak, Ashish; Hurt, Robert H; Kane, Agnes B

    2012-01-13

    Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. Related materials include few-layer-graphene (FLG), ultrathin graphite, graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanosheets (GNS). This review proposes a systematic nomenclature for this set of Graphene-Family Nanomaterials (GFNs) and discusses specific materials properties relevant for biomolecular and cellular interactions. We discuss several unique modes of interaction between GFNs and nucleic acids, lipid bilayers, and conjugated small molecule drugs and dyes. Some GFNs are produced as dry powders using thermal exfoliation, and in these cases, inhalation is a likely route of human exposure. Some GFNs have aerodynamic sizes that can lead to inhalation and substantial deposition in the human respiratory tract, which may impair lung defense and clearance leading to the formation of granulomas and lung fibrosis. The limited literature on in vitro toxicity suggests that GFNs can be either benign or toxic to cells, and it is hypothesized that the biological response will vary across the material family depending on layer number, lateral size, stiffness, hydrophobicity, surface functionalization, and dose. Generation of reactive oxygen species (ROS) in target cells is a potential mechanism for toxicity, although the extremely high hydrophobic surface area of some GFNs may also lead to significant interactions with membrane lipids leading to direct physical toxicity or adsorption of biological molecules leading to indirect toxicity. Limited in vivo studies demonstrate systemic biodistribution and biopersistence of GFNs following intravenous delivery. Similar to other smooth, continuous, biopersistent implants or foreign bodies, GFNs have the potential to induce foreign body tumors. Long-term adverse health impacts must be considered in the design of GFNs for drug delivery, tissue engineering

  17. Graphene oxide vs. reduced graphene oxide as carbon support in porphyrin peroxidase biomimetic nanomaterials.

    PubMed

    Socaci, C; Pogacean, F; Biris, A R; Coros, M; Rosu, M C; Magerusan, L; Katona, G; Pruneanu, S

    2016-02-01

    The paper describes the preparation of supramolecular assemblies of tetrapyridylporphyrin (TPyP) and its metallic complexes with graphene oxide (GO) and thermally reduced graphene oxide (TRGO). The two carbon supports are introducing different characteristics in the absorption spectra of the investigated nanocomposites. Raman spectroscopy shows that the absorption of iron-tetrapyridylporphyrin is more efficient on GO than TRGO, suggesting that oxygen functionalities are involved in the non-covalent interaction between the iron-porphyrin and graphene. The biomimetic peroxidase activity is investigated and the two iron-containing composites exhibit a better catalytic activity than each component of the assembly, and their cobalt and manganese homologues, respectively. The main advantages of this work include the demonstration of graphene oxide as a very good support for graphene-based nanomaterials with peroxidase-like activity (K(M)=0.292 mM), the catalytic activity being observed even with very small amounts of porphyrins (the TPyP:graphene ratio=1:50). Its potential application in the detection of lipophilic antioxidants (vitamin E can be measured in the 10(-5)-10(-4) M range) is also shown.

  18. Colloidal Properties and Stability of Graphene Oxide Nanomaterials in the Aquatic Environment

    EPA Science Inventory

    While graphene oxide (GO) has been found to be the most toxic graphene-based nanomaterial, its environmental fate is still unexplored. In this study, the aggregation kinetics and stability of GO were investigated using time-resolved dynamic light scattering over a wide range of a...

  19. Colloidal Properties and Stability of Graphene Oxide Nanomaterials in the Aquatic Environment

    EPA Science Inventory

    While graphene oxide (GO) has been found to be the most toxic graphene-based nanomaterial, its environmental fate is still unexplored. In this study, the aggregation kinetics and stability of GO were investigated using time-resolved dynamic light scattering over a wide range of a...

  20. Facile synthesis of two-dimensional graphene/SnO₂ /Pt ternary hybrid nanomaterials and their catalytic properties.

    PubMed

    Zhu, Chengzhou; Wang, Ping; Wang, Li; Han, Lei; Dong, Shaojun

    2011-10-05

    In this paper, we reported a simple, aqueous-phase route to the synthesis of two-dimensional graphene/SnO(2) composite nanosheets (GSCN) hybrid nanostructures consisting of 5 nm Pt nanoparticles supported on the both sides of GSCN. Functional two-dimensional GSCN were obtained through the reduction of graphene oxide (GO) using SnCl(2) in the presence of polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA). The main advantages of this preparation are that the reduction of GO, the formation of SnO(2) and the functionalization of GSCN were achieved simultaneously through one-pot reaction. GSCN/Pt ternary hybrid nanomaterials were generated by in situ reduction of negatively charged PtCl(6)(2-) precursors adsorbed on the positively charged surface of GSCN through electrostatic attraction. The as-synthesized GSCN/Pt ternary hybrid nanomaterials exhibited high cycle stabilization during the catalytic reduction of p-nitrophenol into p-aminophenol by NaBH(4). Additionally, our approach is expected to extend to other hybrid nanomaterials. We believe that the obtained GSCN/Pt ternary hybrid nanomaterials have great potential for applications in other field, such as electrochemical energy storage, sensors, and so on.

  1. Nanomaterial resistant microorganism mediated reduction of graphene oxide.

    PubMed

    Chouhan, Raghuraj S; Pandey, Ashish; Qureshi, Anjum; Ozguz, Volkan; Niazi, Javed H

    2016-10-01

    In this study, soil bacteria were isolated from nanomaterials (NMs) contaminated pond soil and enriched in the presence of graphene oxide (GO) in mineral medium to obtain NMs resistant bacteria. The isolated resistant bacteria were biochemically and genetically identified as Fontibacillus aquaticus. The resistant bacteria were allowed to interact with engineered GO in order to study the biotransformation in GO structure. Raman spectra of GO extracted from culture medium revealed decreased intensity ratio of ID/IG with subsequent reduction of CO which was consistent with Fourier transform infrared (FTIR) results. The structural changes and exfoliatied GO nanosheets were also evident from transmission electron microscopy (TEM) images. Ultraviolet-visible spectroscopy, high resolution X-ray diffraction (XRD) and current-voltage measurements confirmed the reduction of GO after the interaction with resistant bacteria. X-ray photoelectron spectroscopy (XPS) analysis of biotransformed GO revealed reduction of oxygen-containing species on the surface of nanosheets. Our results demonstrated that the presented method is an environment friendly, cost effective, simple and based on green approaches for the reduction of GO using NMs resistant bacteria.

  2. Thinnest two-dimensional nanomaterial-graphene for solar energy.

    PubMed

    Hu, Yun Hang; Wang, Hui; Hu, Bo

    2010-07-19

    Graphene is a rapidly rising star in materials science. This two-dimensional material exhibits unique properties, such as low resistance, excellent optical transmittance, and high mechanical and chemical stabilities. These exceptional advantages possess great promise for its potential applications in photovoltaic devices. In this Review, we present the status of graphene research for solar energy with emphasis on solar cells. Firstly, the preparation and properties of graphene are described. Secondly, applications of graphene as transparent conductive electrodes and counter electrodes are presented. Thirdly, graphene-based electron- (or hole) accepting materials for solar energy conversion are evaluated. Fourthly, the promoting effect of graphene on photovoltaic devices and the photocatalytic property of graphene-semiconductor composites are discussed. Finally, the challenges to increase the power conversion efficiency of graphene-based solar cells are explored.

  3. Controlled Covalent Functionalization of Thermally Reduced Graphene Oxide To Generate Defined Bifunctional 2D Nanomaterials

    PubMed Central

    Faghani, Abbas; Donskyi, Ievgen S.; Fardin Gholami, Mohammad; Ziem, Benjamin; Lippitz, Andreas; Unger, Wolfgang E. S.; Böttcher, Christoph; Rabe, Jürgen P.

    2017-01-01

    Abstract A controlled, reproducible, gram‐scale method is reported for the covalent functionalization of graphene sheets by a one‐pot nitrene [2+1] cycloaddition reaction under mild conditions. The reaction between commercially available 2,4,6‐trichloro‐1,3,5‐triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine‐functionalized sheets. The different reactivities of the chlorine substituents on the functionalized graphene allow stepwise post‐modification by manipulating the temperature. This new method provides unique access to defined bifunctional 2D nanomaterials, as exemplified by chiral surfaces and multifunctional hybrid architectures. PMID:28165179

  4. Graphene-like 2D nanomaterial-based biointerfaces for biosensing applications.

    PubMed

    Zhu, Chengzhou; Du, Dan; Lin, Yuehe

    2017-03-15

    Due to their unique structures and multifunctionalities, two-dimensional (2D) nanomaterials have aroused increasing interest in the construction of the novel biointerfaces for biosensing applications. Efforts in constructing novel biointerfaces led to exploit the more versatile and tunable graphene-like 2D nanomaterials (e.g. graphitic carbon nitride, boron nitride, transition metal dichalcogenides, and transition metal oxides) with various structural and compositional characteristics. This review highlights recent efforts in the design of graphene-like 2D nanomaterials and their derived biointerfaces and exploitation of their research on fluorescent sensors and a series of electrochemical sensors, including amperometric, electrochemiluminescence, photoelectrochemical and field-effect transistor sensors. Finally, we discuss some critical challenges and future perspectives in this field. Copyright © 2016. Published by Elsevier B.V.

  5. Preparation, characterization, and electrochemical performances of graphene/Ni(OH)2 hybrid nanomaterials

    NASA Astrophysics Data System (ADS)

    Yang, Duanguang; Wang, Fan; Yan, Jing; Gao, Yong; Li, Huaming

    2013-06-01

    Graphene-based hybrid nanomaterials have recently been investigated and proposed as a promising platform for electronic, optoelectronic, and electrochemical devices because of their high-surface area, remarkable chemical stability, and electrical conductivity. In this study, we demonstrated a facile method for the preparation of graphene/Ni(OH)2 hybrid nanomaterials. First, polymer-functionalized graphene oxide (PGO) was prepared by Cu(I)-catalyzed click coupling of alkyne-functionalized graphene oxide with azide-terminated poly(vinylpyrrolidone). Subsequently, Ni(OH)2 nanoparticles were deposited onto graphene nanosheets using PGO as a template. Upon reduction with NaBH4, graphene/Ni(OH)2 hybrid nanostructures were constructed. The as-prepared graphene/Ni(OH)2 hybrid nanosheets were directly immobilized onto the surface of glassy carbon electrode for glucose determination. The as-fabricated nonenzymatic glucose sensor exhibited a wider linearity range from 0.3 to 750 μM with a detection limit of 30 nM ( S/ N = 3).

  6. Advanced review of graphene-based nanomaterials in drug delivery systems: Synthesis, modification, toxicity and application.

    PubMed

    Zhang, Qi; Wu, Zhuona; Li, Ning; Pu, Yiqiong; Wang, Bing; Zhang, Tong; Tao, Jiansheng

    2017-08-01

    The discovery of graphene, a notable achievement in the field of novel carbon nanomaterials, has triggered the worldwide exploration of the biomedical applications of this material since 2004 because of its unique properties. The two-dimensional planar structure, large surface area, chemical stability, mechanical stability, and good biocompatibility of graphene are promising for applications in drug delivery systems (DDSs). In this review, we briefly discuss the characteristics, synthesis, and modification of graphene. We also investigate its toxicity and its applications in DDSs, with several representative examples. This review presents a comprehensive summary of graphene-based nanomaterials from their characteristics to their synthesis and applications, as well as their in vitro and in vivo evaluation in medicine. This paper provides a guiding strategy for the selection of optimal approaches to the fabrication of nanocarriers that are suitable for medical treatments and to controlling the toxicity within therapeutic safety limits. The promising achievements made with graphene-based nanomaterials indicate several possibilities for further biomedical research, as well as theoretical and applied development. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Recent advances in graphene-based nanomaterials for fabricating electrochemical hydrogen peroxide sensors.

    PubMed

    Zhang, Ruizhong; Chen, Wei

    2017-03-15

    Due to the large specific surface area, extraordinary mechanical flexibility, chemical stability, and superior electrical and thermal conductivities, graphene (G)-based materials have recently opened up an exciting field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. In the past several years, graphene-based materials have been well designed, synthesized, and investigated for sensing applications. In this review, we discuss the synthesis and application of graphene-based 2D nanomaterials for the fabrication of hydrogen peroxide (H2O2) electrochemical sensors. In particular, graphene-based nanomaterials as immobilization matrix of heme proteins for the fabrication of enzymatic H2O2 electrochemical biosensors is first summarized. Then, the application of graphene-based electrocatalysts (metal-free, noble-metals and non-noble metals) in constructing non-enzymatic H2O2 electrochemical sensors is discussed in detail. We hope that this review is helpful to push forward the advancement of this academic issue (189 references).

  8. Recent advances in electrochemical biosensors based on graphene two-dimensional nanomaterials.

    PubMed

    Song, Yang; Luo, Yanan; Zhu, Chengzhou; Li, He; Du, Dan; Lin, Yuehe

    2016-02-15

    Graphene as a star among two-dimensional nanomaterials has attracted tremendous research interest in the field of electrochemistry due to their intrinsic properties, including the electronic, optical, and mechanical properties associated with their planar structure. The marriage of graphene and electrochemical biosensors has created many ingenious biosensing strategies for applications in the areas of clinical diagnosis and food safety. This review provides a comprehensive overview of the recent advances in the development of graphene based electrochemical biosensors. Special attention is paid to graphene-based enzyme biosensors, immunosensors, and DNA biosensors. Future perspectives on high-performance graphene-based electrochemical biosensors are also discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Vibrational properties of noncovalently oligothiophene-functionalized graphene nanomaterials

    NASA Astrophysics Data System (ADS)

    Boutahir, M.; Rahmani, A. H.; Chadli, H.; Rahmani, A.

    2016-10-01

    In this paper, the non resonant Raman spectra of hybrid nanostructures obtained by confinement of oligothiophene derivatives in two sheets of graphene are calculated in the framework of spectral moments method, together with a bond-polarizability model. Minimum energy calculations are performed, using a convenient Lennard-Jones expression of the van der Waals intermolecular potential, to derive the optimum configurations of oligothiophene with graphene. Parallel configuration of thiophene molecules with respect to the graphene plane was considered.

  10. Investigating the Toxicity and Environmental Fate of Graphene Nanomaterials

    EPA Science Inventory

    The Hersam Laboratory at Northwestern University works with the Center for Environmental Implications of Nanotechnology and the United States Environmental Protection Agency to study the toxicity and environmental fate of emergent nanomaterials, specifically carbon-based nanomate...

  11. Investigating the Toxicity and Environmental Fate of Graphene Nanomaterials

    EPA Science Inventory

    The Hersam Laboratory at Northwestern University works with the Center for Environmental Implications of Nanotechnology and the United States Environmental Protection Agency to study the toxicity and environmental fate of emergent nanomaterials, specifically carbon-based nanomate...

  12. Graphene, carbon nanotubes, zinc oxide and gold as elite nanomaterials for fabrication of biosensors for healthcare.

    PubMed

    Kumar, Sandeep; Ahlawat, Wandit; Kumar, Rajesh; Dilbaghi, Neeraj

    2015-08-15

    Technological advancements worldwide at rapid pace in the area of materials science and nanotechnology have made it possible to synthesize nanoparticles with desirable properties not exhibited by the bulk material. Among variety of available nanomaterials, graphene, carbon nanotubes, zinc oxide and gold nanopartilces proved to be elite and offered amazing electrochemical biosensing. This encourages us to write a review which highlights the recent achievements in the construction of genosensor, immunosensor and enzymatic biosensor based on the above nanomaterials. Carbon based nanomaterials offers a direct electron transfer between the functionalized nanomaterials and active site of bioreceptor without involvement of any mediator which not only amplifies the signal but also provide label free sensing. Gold shows affinity towards immunological molecules and is most routinely used for immunological sensing. Zinc oxide can easily immobilize proteins and hence offers a large group of enzyme based biosensor. Modification of the working electrode by introduction of these nanomaterials or combination of two/three of above nanomaterials together and forming a nanocomposite reflected the best results with excellent stability, reproducibility and enhanced sensitivity. Highly attractive electrochemical properties and electrocatalytic activity of these elite nanomaterials have facilitated achievement of enhanced signal amplification needed for the construction of ultrasensitive electrochemical affinity biosensors for detection of glucose, cholesterol, Escherichia coli, influenza virus, cancer, human papillomavirus, dopamine, glutamic acid, IgG, IgE, uric acid, ascorbic acid, acetlycholine, cortisol, cytosome, sequence specific DNA and amino acids. Recent researches for bedside biosensors are also discussed.

  13. Investigation of graphene-based nanomaterial as nanocarrier for adsorption of paclitaxel anticancer drug: a molecular dynamics simulation study.

    PubMed

    Hasanzade, Zohre; Raissi, Heidar

    2017-02-01

    In this work, molecular dynamics simulations are used to study the adsorption of paclitaxel (PTX) drug on the graphene-based nanomaterials including graphene (G), graphene oxide (GO), and functionalized GO with chitosan (GO-CS). The drug is adsorbed through different patterns on the surface of graphene-based nanomaterials. Our results show that PTX on graphene is adsorbed more quickly than other systems. Comparing center of mass (COM) in GO and GO-CS systems indicated that PTX approaches GO-CS surface faster than GO surface. The binding of PTX molecule to graphene surface is stronger than the other investigated systems. Our study indicated that π-π stacking and hydrophobic interactions are the main driving forces for the adsorption of the drug on graphene, while the adsorption of PTX on GO-CS is dominated by the formation of hydrogen bonds. It is found that the number of hydrogen bonds in PTX-GO-CS system is more than that of PTX-GO emphasizing the advantages of the functional group of chitosan in improving the adsorption of the drug onto nanomaterial. These results suggest that hydrogen bond, π-π stacking, and hydrophobic interactions play a key role in the adsorption of PTX in graphene-based nanomaterials. In spite of similar dimensions of investigated nanomaterials, the difference in surface chemistries and also the type of functional group can be effective factors in determining their interactions with PTX.

  14. Chemical preparation of graphene-based nanomaterials and their applications in chemical and biological sensors.

    PubMed

    Jiang, Hongji

    2011-09-05

    Graphene is a flat monolayer of carbon atoms packed tightly into a 2D honeycomb lattice that shows many intriguing properties meeting the key requirements for the implementation of highly excellent sensors, and all kinds of proof-of-concept sensors have been devised. To realize the potential sensor applications, the key is to synthesize graphene in a controlled way to achieve enhanced solution-processing capabilities, and at the same time to maintain or even improve the intrinsic properties of graphene. Several production techniques for graphene-based nanomaterials have been developed, ranging from the mechanical cleavage and chemical exfoliation of high-quality graphene to direct growth onto different substrates and the chemical routes using graphite oxide as a precusor to the newly developed bottom-up approach at the molecular level. The current review critically explores the recent progress on the chemical preparation of graphene-based nanomaterials and their applications in sensors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Adsorption of halogenated aliphatic contaminants by graphene nanomaterials.

    PubMed

    Zhou, Yang; Apul, Onur Guven; Karanfil, Tanju

    2015-08-01

    In this study, adsorption of ten environmentally halogenated aliphatic synthetic organic compounds (SOCs) by a pristine graphene nanosheet (GNS) and a reduced graphene oxide (rGO) was examined, and their adsorption behaviors were compared with those of a single-walled carbon nanotube (SWCNT) and a granular activated carbon (GAC). In addition, the impacts of background water components (i.e., natural organic matter (NOM), ionic strength (IS) and pH) on the SOC adsorption behavior were investigated. The results indicated HD3000 and SWCNT with higher microporous volumes exhibited higher adsorption capacities for the selected aliphatic SOCs than graphenes, demonstrating microporosity of carbonaceous adsorbents played an important role in the adsorption. Analysis of adsorption isotherms demonstrated that hydrophobic interactions were the dominant contributor to the adsorption of aliphatic SOCs by graphenes. However, π-π electron donor-acceptor and van der Waals interactions are likely the additional mechanisms contributing to the adsorption of aliphatic SOCs on graphenes. Among the three background solution components examined, NOM showed the most influential effect on adsorption of the selected aliphatic SOCs, while pH and ionic strength had a negligible effects. The NOM competition on aliphatic adsorption was less pronounced on graphenes than SWCNT. Overall, in terms of adsorption capacities, graphenes tested in this study did not exhibit a major advantage over SWCNT and GAC for the adsorption of aliphatic SOCs.

  16. 2-Dimensional graphene as a route for emergence of additional dimension nanomaterials.

    PubMed

    Patra, Santanu; Roy, Ekta; Tiwari, Ashutosh; Madhuri, Rashmi; Sharma, Prashant K

    2017-03-15

    Dimension has a different and impactful significance in the field of innovation, research and technologies. Starting from one-dimension, now, we all are moving towards 3-D visuals and try to do the things in this dimension. However, we still have some very innovative and widely applicable nanomaterials, which have tremendous potential in the form of 2-D only i.e. graphene. In this review, we have tried to incorporate the reported pathways used so far for modification of 2-D graphene sheets to make is three-dimensional. The modified graphene been applied in many fields like supercapacitors, sensors, catalysis, energy storage devices and many more. In addition, we have also incorporated the conversion of 2-D graphene to their various other dimensions like zero-, one- or three-dimensional nanostructures.

  17. Computational nanomaterials for novel desalination membrane design: Nanoporous graphene

    NASA Astrophysics Data System (ADS)

    Cohen-Tanugi, David; Grossman, Jeffrey C.

    2012-02-01

    We describe a novel approach for desalination based on nanoporous graphene. Our molecular dynamics calculations show that freestanding graphene patterned with nanometer-sized pores can act as an ultra-thin filtration membrane. Due to size exclusion and chemical interactions with the confining pores, salt ions can be blocked from permeating the membrane at sufficiently small pore diameters. Notably, the pore diameter and the chemical interactions at the water-membrane interface are most important criteria for this system's desalination performance. We will share insights from Molecular Dynamics calculations regarding the theoretical performance of this membrane system and the effects of chemical passivation of the graphene pores on the filtration dynamics. Although the narrow range of acceptable pore sizes suggests that further design innovations will be necessary at the molecular scale before large-scale applications are possible, our existing results predict that pressure requirements for this system can be made roughly competitive with commercial Reverse Osmosis.

  18. Graphene and Other Nanomaterial-Based Electrochemical Aptasensors

    PubMed Central

    Hernandez, Frank J.; Ozalp, Veli Cengiz

    2012-01-01

    Electrochemical aptasensors, which are based on the specificity of aptamer-target recognition, with electrochemical transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. Aptamers are functional nucleic acids with specific and high affinity to their targets, similar to antibodies. However, they are completely selected in vitro in contrast to antibodies. Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices. In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors. In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors. PMID:25585628

  19. Adsorption of Estrogen Contaminants by Graphene Nanomaterials under Natural Organic Matter Preloading: Comparison to Carbon Nanotube, Biochar, and Activated Carbon.

    PubMed

    Jiang, Luhua; Liu, Yunguo; Liu, Shaobo; Zeng, Guangming; Hu, Xinjiang; Hu, Xi; Guo, Zhi; Tan, Xiaofei; Wang, Lele; Wu, Zhibin

    2017-06-06

    Adsorption of two estrogen contaminants (17β-estradiol and 17α-ethynyl estradiol) by graphene nanomaterials was investigated and compared to those of a multi-walled carbon nanotube (MWCNT), a single-walled carbon nanotube (SWCNT), two biochars, a powdered activated carbon (PAC), and a granular activate carbon (GAC) in ultrapure water and in the competition of natural organic matter (NOM). Graphene nanomaterials showed comparable or better adsorption ability than carbon nanotubes (CNTs), biochars (BCs), and activated carbon (ACs) under NOM preloading. The competition of NOM decreased the estrogen adsorption by all adsorbents. However, the impact of NOM on the estrogen adsorption was smaller on graphenes than CNTs, BCs, and ACs. Moreover, the hydrophobicity of estrogens also affected the uptake of estrogens. These results suggested that graphene nanomaterials could be used to removal estrogen contaminants from water as an alternative adsorbent. Nevertheless, if transferred to the environment, they would also adsorb estrogen contaminants, leading to great environmental hazards.

  20. Safety and biocompatibility of graphene: A new generation nanomaterial for biomedical application.

    PubMed

    Syama, S; Mohanan, P V

    2016-05-01

    Graphene, a material with great application potential is expected to revolutionize various fields in the near future particularly biomedical field with its inherent properties. However, significant increase in the research on graphene in the recent years has created anxiety about their safety/biocompatibility towards living organisms. Though there is increase in reports on graphene synthesis and application, in parallel reports on unwanted toxic effects of these materials is under scrutiny. Before exploiting their use, any engineered nanomaterials should undergo through investigation regarding the risk and health hazards imposed by them. Toxicity of nanomaterial depends on many factors like size, shape, surface chemistry, dose, duration and the biological milieu. In this account, we reviewed physico-chemical properties of graphene that plays a key role in toxicity prediction. We also detailed some examples of the in vitro and in vivo toxicity studies that have been published so far. The potential environmental risk associated with these carbon materials is also addressed, in order to avoid unintentional leaching of these materials into surface water. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Graphene nanomaterials as biocompatible and conductive scaffolds for stem cells: impact for tissue engineering and regenerative medicine.

    PubMed

    Menaa, Farid; Abdelghani, Adnane; Menaa, Bouzid

    2015-12-01

    The discovery of the interesting intrinsic properties of graphene, a two-dimensional nanomaterial, has boosted further research and development for various types of applications from electronics to biomedicine. During the last decade, graphene and several graphene-derived materials, such as graphene oxide, carbon nanotubes, activated charcoal composite, fluorinated graphenes and three-dimensional graphene foams, have been extensively explored as components of biosensors or theranostics, or to remotely control cell-substrate interfaces, because of their remarkable electro-conductivity. To date, despite the intensive progress in human stem cell research, only a few attempts to use carbon nanotechnology in the stem cell field have been reported. Interestingly, most of the recent in vitro studies indicate that graphene-based nanomaterials (i.e. mainly graphene, graphene oxide and carbon nanotubes) promote stem cell adhesion, growth, expansion and differentiation. Although cell viability in vitro is not affected, their potential nanocytoxicity (i.e. nanocompatibility and consequences of uncontrolled nanobiodegradability) in a clinical setting using humans remains unknown. Therefore, rigorous internationally standardized clinical studies in humans that would aim to assess their nanotoxicology are requested. In this paper we report and discuss the recent and pertinent findings about graphene and derivatives as valuable nanomaterials for stem cell research (i.e. culture, maintenance and differentiation) and tissue engineering, as well as for regenerative, translational and personalized medicine (e.g. bone reconstruction, neural regeneration). Also, from scarce nanotoxicological data, we also highlight the importance of functionalizing graphene-based nanomaterials to minimize the cytotoxic effects, as well as other critical safety parameters that remain important to take into consideration when developing nanobionanomaterials.

  2. Interactions of graphene oxide nanomaterials with natural organic matter and metal oxide surfaces.

    PubMed

    Chowdhury, Indranil; Duch, Matthew C; Mansukhani, Nikhita D; Hersam, Mark C; Bouchard, Dermont

    2014-08-19

    Interactions of graphene oxide (GO) nanomaterials with natural organic matter (NOM) and metal oxide surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Three different types of NOM were studied: Suwannee River humic and fulvic acids (SRHA and SRFA) and alginate. Aluminum oxide surface was used as a model metal oxide surface. Deposition trends show that GO has the highest attachment on alginate, followed by SRFA, SRHA, and aluminum oxide surfaces, and that GO displayed higher interactions with all investigated surfaces than with silica. Deposition and release behavior of GO on aluminum oxide surface is very similar to positively charged poly-L-lysine-coated surface. Higher interactions of GO with NOM-coated surfaces are attributed to the hydroxyl, epoxy, and carboxyl functional groups of GO; higher deposition on alginate-coated surfaces is attributed to the rougher surface created by the extended conformation of the larger alginate macromolecules. Both ionic strength (IS) and ion valence (Na(+) vs Ca(2+)) had notable impact on interactions of GO with different environmental surfaces. Due to charge screening, increased IS resulted in greater deposition for NOM-coated surfaces. Release behavior of deposited GO varied significantly between different environmental surfaces. All surfaces showed significant release of deposited GO upon introduction of low IS water, indicating that deposition of GO on these surfaces is reversible. Release of GO from NOM-coated surfaces decreased with IS due to charge screening. Release rates of deposited GO from alginate-coated surface were significantly lower than from SRHA and SRFA-coated surfaces due to trapping of GO within the rough surface of the alginate layer.

  3. Graphene-like two-dimensional layered nanomaterials: applications in biosensors and nanomedicine

    NASA Astrophysics Data System (ADS)

    Yang, Guohai; Zhu, Chengzhou; Du, Dan; Zhu, Junjie; Lin, Yuehe

    2015-08-01

    The development of nanotechnology provides promising opportunities for various important applications. The recent discovery of atomically-thick two-dimensional (2D) nanomaterials can offer manifold perspectives to construct versatile devices with high-performance to satisfy multiple requirements. Many studies directed at graphene have stimulated renewed interest on graphene-like 2D layered nanomaterials (GLNs). GLNs including boron nitride nanosheets, graphitic-carbon nitride nanosheets and transition metal dichalcogenides (e.g. MoS2 and WS2) have attracted significant interest in numerous research fields from physics and chemistry to biology and engineering, which has led to numerous interdisciplinary advances in nano science. Benefiting from the unique physical and chemical properties (e.g. strong mechanical strength, high surface area, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization), these 2D layered nanomaterials have shown great potential in biochemistry and biomedicine. This review summarizes recent advances of GLNs in applications of biosensors and nanomedicine, including electrochemical biosensors, optical biosensors, bioimaging, drug delivery and cancer therapy. Current challenges and future perspectives in these rapidly developing areas are also outlined. It is expected that they will have great practical foundation in biomedical applications with future efforts.

  4. Graphene-like two-dimensional layered nanomaterials: applications in biosensors and nanomedicine.

    PubMed

    Yang, Guohai; Zhu, Chengzhou; Du, Dan; Zhu, Junjie; Lin, Yuehe

    2015-09-14

    The development of nanotechnology provides promising opportunities for various important applications. The recent discovery of atomically-thick two-dimensional (2D) nanomaterials can offer manifold perspectives to construct versatile devices with high-performance to satisfy multiple requirements. Many studies directed at graphene have stimulated renewed interest on graphene-like 2D layered nanomaterials (GLNs). GLNs including boron nitride nanosheets, graphitic-carbon nitride nanosheets and transition metal dichalcogenides (e.g. MoS2 and WS2) have attracted significant interest in numerous research fields from physics and chemistry to biology and engineering, which has led to numerous interdisciplinary advances in nano science. Benefiting from the unique physical and chemical properties (e.g. strong mechanical strength, high surface area, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization), these 2D layered nanomaterials have shown great potential in biochemistry and biomedicine. This review summarizes recent advances of GLNs in applications of biosensors and nanomedicine, including electrochemical biosensors, optical biosensors, bioimaging, drug delivery and cancer therapy. Current challenges and future perspectives in these rapidly developing areas are also outlined. It is expected that they will have great practical foundation in biomedical applications with future efforts.

  5. Dispersing carbon-based nanomaterials in aqueous phase by graphene oxides.

    PubMed

    Li, Yilun; Yang, Juan; Zhao, Qinghua; Li, Yan

    2013-11-05

    Graphene oxides (GO) can be considered as polyelectrolytes with surfactant-like characteristics. On one hand, due to the electrical repulsion between the negatively charged ionized edges, GO exhibits great water solubility; on the other hand, its hydrophobic central plane retains the potential of strong π-π interaction with other conjugated sp(2) network structures. Therefore, it is expected that GO can serve as an excellent dispersing agent for dispersion of various carbon-based nanomaterials in aqueous phase. Here we report a systematic study of dispersing various carbon-based nanomaterials, including SWNTs, C60, and graphene, by aqueous GO. The GO-dispersed all-carbon nanocomposites are characterized using various spectroscopic methods and electron microscopies, and their stabilities are tested. Compared to other dispersing agents, the GO concentration is much lower than the concentrations of other dispersing agents used when similar contents of carbon-based nanomaterials are dispersed. Involving only simple ultrasonication and centrifugation processes, GO dispersion thus offers an easy manipulation for large-scale solution-dispersed all-carbon nanocomposites.

  6. Extended friction elucidates the breakdown of fast water transport in graphene oxide membranes

    NASA Astrophysics Data System (ADS)

    Montessori, A.; Amadei, C. A.; Falcucci, G.; Sega, M.; Vecitis, C. D.; Succi, S.

    2016-12-01

    The understanding of water transport in graphene oxide (GO) membranes stands out as a major theoretical problem in graphene research. Notwithstanding the intense efforts devoted to the subject in the recent years, a consolidated picture of water transport in GO membranes is yet to emerge. By performing mesoscale simulations of water transport in ultrathin GO membranes, we show that even small amounts of oxygen functionalities can lead to a dramatic drop of the GO permeability, in line with experimental findings. The coexistence of bulk viscous dissipation and spatially extended molecular friction results in a major decrease of both slip and bulk flow, thereby suppressing the fast water transport regime observed in pristine graphene nanochannels. Inspection of the flow structure reveals an inverted curvature in the near-wall region, which connects smoothly with a parabolic profile in the bulk region. Such inverted curvature is a distinctive signature of the coexistence between single-particle zero-temperature (noiseless) Langevin friction and collective hydrodynamics. The present mesoscopic model with spatially extended friction may offer a computationally efficient tool for future simulations of water transport in nanomaterials.

  7. Graphene-based nanomaterials as heterogeneous acid catalysts: a comprehensive perspective.

    PubMed

    Garg, Bhaskar; Bisht, Tanuja; Ling, Yong-Chien

    2014-09-15

    Acid catalysis is quite prevalent and probably one of the most routine operations in both industrial processes and research laboratories worldwide. Recently, "graphene", a two dimensional single-layer carbon sheet with hexagonal packed lattice structure, imitative of nanomaterials, has shown great potential as alternative and eco-friendly solid carbocatalyst for a variety of acid-catalyzed reactions. Owing to their exceptional physical, chemical, and mechanical properties, graphene-based nanomaterials (G-NMs) offer highly stable Brønsted acidic sites, high mass transfer, relatively large surface areas, water tolerant character, and convenient recoverability as well as recyclability, whilst retaining high activity in acid-catalyzed chemical reactions. This comprehensive review focuses on the chemistry of G-NMs, including their synthesis, characterization, properties, functionalization, and up-to-date applications in heterogeneous acid catalysis. In line with this, in certain instances readers may find herein some criticisms that should be taken as constructive and would be of value in understanding the scope and limitations of current approaches utilizing graphene and its derivatives for the same.

  8. An extended defect in graphene as a metallic wire.

    PubMed

    Lahiri, Jayeeta; Lin, You; Bozkurt, Pinar; Oleynik, Ivan I; Batzill, Matthias

    2010-05-01

    Many proposed applications of graphene require the ability to tune its electronic structure at the nanoscale. Although charge transfer and field-effect doping can be applied to manipulate charge carrier concentrations, using them to achieve nanoscale control remains a challenge. An alternative approach is 'self-doping', in which extended defects are introduced into the graphene lattice. The controlled engineering of these defects represents a viable approach to creation and nanoscale control of one-dimensional charge distributions with widths of several atoms. However, the only experimentally realized extended defects so far have been the edges of graphene nanoribbons, which show dangling bonds that make them chemically unstable. Here, we report the realization of a one-dimensional topological defect in graphene, containing octagonal and pentagonal sp(2)-hybridized carbon rings embedded in a perfect graphene sheet. By doping the surrounding graphene lattice, the defect acts as a quasi-one-dimensional metallic wire. Such wires may form building blocks for atomic-scale, all-carbon electronics.

  9. Humic acid acts as a natural antidote of graphene by regulating nanomaterial translocation and metabolic fluxes in vivo.

    PubMed

    Hu, Xiangang; Mu, Li; Kang, Jia; Lu, Kaicheng; Zhou, Ruiren; Zhou, Qixing

    2014-06-17

    Graphene-related research has intensified rapidly in a wide range of disciplines, but few studies have examined ecosystem risks, particularly phytotoxicity. This study revealed that graphene significantly inhibits the number of wheat roots and the biosynthesis of chlorophyll, and altered the morphology of shoots. Humic acid (HA), a ubiquitous form of natural organic matter, significantly (P < 0.05) relieved this phytotoxicity and recovered the sharp morphology of shoot tips. Both graphene and graphene-HA were transferred from wheat roots to shoots and were found in the cytoplasms and chloroplasts. HA increased the disordered structure and surface negative charges, and reduced the aggregation of graphene. HA enhanced the storage of graphene in vacuoles, potentially indicating an effective detoxification path. The content of cadaverine, alkane, glyconic acid, and aconitic acid was up-regulated by graphene, greatly contributing to the observed phytotoxicity. Conversely, inositol, phenylalanine, phthalic acid, and octadecanoic acid were up-regulated by graphene-HA. The metabolic pathway analysis revealed that the direction of metabolic fluxes governed nanotoxicity. This work presents the innovative concept that HA acts as a natural antidote of graphene by regulating its translocation and metabolic fluxes in vivo. This knowledge is critical for avoiding the overestimation of nanomaterial risks and can be used to control nanomaterial contamination.

  10. Not just graphene: The wonderful world of carbon and related nanomaterials

    SciTech Connect

    Gogotsi, Yury

    2015-11-27

    Carbon, with its variety of allotropes and forms, is the most versatile material, and virtually any combination of mechanical, optical, electrical, and chemical properties can be achieved with carbon by controlling its structure and surface chemistry. The goal of this article is to help readers appreciate the variety of carbon nanomaterials and to describe some engineering applications of the most important of these. Many different materials are needed to meet a variety of performance requirements, but they can all be built of carbon. Considering the example of supercapacitor electrodes, zero- and one-dimensional nanoparticles, such as carbon onions and nanotubes, respectively, deliver very high power because of fast ion sorption/desorption on their outer surfaces. Two-dimensional (2D) graphene offers higher charge/discharge rates than porous carbons and a high volumetric energy density. Three-dimensional porous activated, carbide-derived, and templated carbon networks, with high surface areas and porosities in the angstrom or nanometer range, can provide high energy densities if the pore size is matched with the electrolyte ion size. Finally, carbon-based nanostructures further expand the range of available nanomaterials: Recently discovered 2D transition-metal carbides (MXenes) have already grown into a family with close to 20 members in about four years and challenge graphene in some applications.

  11. Low-toxic and safe nanomaterials by surface-chemical design, carbon nanotubes, fullerenes, metallofullerenes, and graphenes

    NASA Astrophysics Data System (ADS)

    YanEqual Contribution, Liang; Zhao, Feng; Li, Shoujian; Hu, Zhongbo; Zhao, Yuliang

    2011-02-01

    The toxicity grade for a bulk material can be approximately determined by three factors (chemical composition, dose, and exposure route). However, for a nanomaterial it depends on more than ten factors. Interestingly, some nano-factors (like huge surface adsorbability, small size, etc.) that endow nanomaterials with new biomedical functions are also potential causes leading to toxicity or damage to the living organism. Is it possible to create safe nanomaterials if such a number of complicated factors need to be regulated? We herein try to find answers to this important question. We first discuss chemical processes that are applicable for nanosurface modifications, in order to improve biocompatibility, regulate ADME, and reduce the toxicity of carbon nanomaterials (carbon nanotubes, fullerenes, metallofullerenes, and graphenes). Then the biological/toxicological effects of surface-modified and unmodified carbon nanomaterials are comparatively discussed from two aspects: the lowered toxic responses or the enhanced biomedical functions. We summarize the eight biggest challenges in creating low-toxicity and safer nanomaterials and some significant topics of future research needs: to find out safer nanofactors; to establish controllable surface modifications and simpler chemistries for low-toxic nanomaterials; to explore the nanotoxicity mechanisms; to justify the validity of current toxicological theories in nanotoxicology; to create standardized nanomaterials for toxicity tests; to build theoretical models for cellular and molecular interactions of nanoparticles; and to establish systematical knowledge frameworks for nanotoxicology.

  12. Graphene valley pseudospin filter using an extended line defect

    NASA Astrophysics Data System (ADS)

    Gunlycke, Daniel; White, Carter

    2011-03-01

    Although graphene exhibits excellent electron and thermal transport properties, it does not have an intrinsic band gap, required to use graphene as a replacement material for silicon and other semiconductors in conventional electronics. The band structure of graphene with its two cones near the Fermi level, however, offers opportunities to develop non-traditional applications. One such avenue is to exploit the valley degeneracy in graphene to develop valleytronics. A central component in valleytronics is the valley filter, just as the spin filter is central in spintronics. Herein, we present a two-dimensional valley filter based on scattering of electrons and holes off a recently observed extended line defect [Nat. Nanotech.5, 326 (2010)] within graphene. The transmission probability depends strongly on the valley pseudospin and the angle of incidence of the incident quasiparticles. Quasiparticles arriving at the line defect at a high angle of incidence lead to a valley polarization of the transmitted beam that is near 100 percent. This work was supported by ONR, directly and through NRL.

  13. A review of toxicity studies on graphene-based nanomaterials in laboratory animals.

    PubMed

    Ema, Makoto; Gamo, Masashi; Honda, Kazumasa

    2017-04-01

    We summarized the findings of toxicity studies on graphene-based nanomaterials (GNMs) in laboratory mammals. The inhalation of graphene (GP) and graphene oxide (GO) induced only minimal pulmonary toxicity. Bolus airway exposure to GP and GO caused acute and subacute pulmonary inflammation. Large-sized GO (L-GO) was more toxic than small-sized GO (S-GO). Intratracheally administered GP passed through the air-blood barrier into the blood and intravenous GO distributed mainly in the lungs, liver, and spleen. S-GO and L-GO mainly accumulated in the liver and lungs, respectively. Limited information showed the potential behavioral, reproductive, and developmental toxicity and genotoxicity of GNMs. There are indications that oxidative stress and inflammation may be involved in the toxicity of GNMs. The surface reactivity, size, and dispersion status of GNMs play an important role in the induction of toxicity and biodistribution of GNMs. Although this review paper provides initial information on the potential toxicity of GNMs, data are still very limited, especially when taking into account the many different types of GNMs and their potential modifications. To fill the data gap, further studies should be performed using laboratory mammals exposed using the route and dose anticipated for human exposure scenarios.

  14. Colloidal properties and stability of graphene oxide nanomaterials in the aquatic environment.

    PubMed

    Chowdhury, Indranil; Duch, Matthew C; Mansukhani, Nikhita D; Hersam, Mark C; Bouchard, Dermont

    2013-06-18

    While graphene oxide (GO) has been found to be the most toxic graphene-based nanomaterial, its environmental fate is still unexplored. In this study, the aggregation kinetics and stability of GO were investigated using time-resolved dynamic light scattering over a wide range of aquatic chemistries (pH, salt types (NaCl, MgCl2, CaCl2), ionic strength) relevant to natural and engineered systems. Although pH did not have a notable influence on GO stability from pH 4 to 10, salt type and ionic strength had significant effects on GO stability due to electrical double layer compression, similar to other colloidal particles. The critical coagulation concentration (CCC) values of GO were determined to be 44 mM NaCl, 0.9 mM CaCl2, and 1.3 mM MgCl2. Aggregation and stability of GO in the aquatic environment followed colloidal theory (DLVO and Schulze-Hardy rule), even though GO's shape is not spherical. CCC values of GO were lower than reported fullerene CCC values and higher than reported carbon nanotube CCC values. CaCl2 destabilized GO more aggressively than MgCl2 and NaCl due to the binding capacity of Ca(2+) ions with hydroxyl and carbonyl functional groups of GO. Natural organic matter significantly improved the stability of GO in water primarily due to steric repulsion. Long-term stability studies demonstrated that GO was highly stable in both natural and synthetic surface waters, although it settled quickly in synthetic groundwater. While GO remained stable in synthetic influent wastewater, effluent wastewater collected from a treatment plant rapidly destabilized GO, indicating GO will settle out during the wastewater treatment process and likely accumulate in biosolids and sludge. Overall, our findings indicate that GO nanomaterials will be stable in the natural aquatic environment and that significant aqueous transport of GO is possible.

  15. Photoacoustic bio-quantification of graphene based nanomaterials at a single cell level (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Nedosekin, Dmitry A.; Nolan, Jacqueline; Biris, Alexandru S.; Zharov, Vladimir P.

    2017-03-01

    Arkansas Nanomedicine Center at the University of Arkansas for Medical Sciences in collaboration with other Arkansas Universities and the FDA-based National Center of Toxicological Research in Jefferson, AR is developing novel techniques for rapid quantification of graphene-based nanomaterials (GBNs) in various biological samples. All-carbon GBNs have wide range of potential applications in industry, agriculture, food processing and medicine; however, quantification of GBNs is difficult in carbon reach biological tissues. The accurate quantification of GBNs is essential for research on material toxicity and the development of GBNs-based drug delivery platforms. We have developed microscopy and cytometry platforms for detection and quantification of GBNs in single cells, tissue and blood samples using photoacoustic contrast of GBNs. We demonstrated PA quantification of individual graphene uptake by single cells. High-resolution PA microscopy provided mapping of GBN distribution within live cells to establish correlation with intracellular toxic phenomena using apoptotic and necrotic assays. This new methodology and corresponding technical platform provide the insight on possible toxicological risks of GBNs at singe cells levels. In addition, in vivo PA image flow cytometry demonstrated the capability to monitor of GBNs pharmacokinetics in mouse model and to map the resulting biodistribution of GBNs in mouse tissues. The integrated PA platform provided an unprecedented sensitivity toward GBNs and allowed to enhance conventional toxicology research by providing a direct correlation between uptake of GBNs at a single cell level and cell viability status.

  16. Magnetic nanomaterial derived from graphene oxide/layered double hydroxide hybrid for efficient removal of methyl orange from aqueous solution.

    PubMed

    Yang, Zhe; Ji, Shanshan; Gao, Wei; Zhang, Chao; Ren, Lulu; Tjiu, Weng Weei; Zhang, Zheng; Pan, Jisheng; Liu, Tianxi

    2013-10-15

    Magnetic hybrid nanomaterials composed of reduced graphene oxide, zero-valent nickel, and NiAl-mixed metal oxides (rGO/Ni/MMO) have been synthesized by calcining graphene oxide (GO)/layered double hydroxide (LDH) hybrid in nitrogen atmosphere. Structural characterizations demonstrate that with the presence of GO substrate, NiAl-LDHs can be reduced into zero-valent Ni and NiAl-MMOs during calcination. Transmission electron microscopy (TEM) is used to investigate the morphology of the as-prepared hybrid nanomaterials, demonstrating that the introduction of GO substrate prevents the aggregation of LDHs. Magnetism characterization proves the ferromagnetic property of rGO/Ni/MMO hybrid. This magnetic hybrid nanomaterial exhibits excellent adsorption ability toward methyl orange (MO) in aqueous solutions. The kinetics of the adsorption process and the adsorption isotherm are investigated. The MO removal process is found to obey the Redlich-Peterson isotherm model, and its kinetics follows pseudo-second-order rate equation. In addition, the magnetic hybrid also exhibits good recycle ability for MO removal. This novel magnetic hybrid nanomaterial derived from GO/LDH hybrid demonstrates great potential in the applications of water treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Enhanced dehydrochlorination of 1,1,2,2-tetrachloroethane by graphene-based nanomaterials.

    PubMed

    Li, Xuguang; Chen, Weifeng; Zhang, Chengdong; Li, Yao; Wang, Fanfan; Chen, Wei

    2016-07-01

    Graphene oxide (GO) and reduced graphene oxide (RGO) materials contain a variety of surface O-functional groups that are chemically reactive. When released into the environment these materials may significantly affect the abiotic transformation of organic contaminants, and therefore, may alter their fate and risks. We found that two GO and five RGO materials that varied in C/O ratio, hydrophobicity, and type/distribution of surface O-functionality all had catalytic effects on the dehydrochlorination of 1,1,2,2-tetrachloroethane (TeCA). Even though the catalytic effects of the materials originated from their deprotonated surface O-functional groups, which served as conjugated bases to catalyze the reaction, the catalytic efficiencies of the materials did not correlate strongly with their surface O contents. The spectroscopic evidence (X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy), surface charge data, and adsorption experiments demonstrated that the catalytic efficiencies of the GO/RGO materials were controlled by a complex interplay of the type and distribution of surface O-functionality, as well as adsorption affinity of the materials. Both Ca(2+) and Mg(2+) inhibited the catalytic efficiency of the materials by binding to the surface O-functional groups, and consequently, decreasing the basicity of the functional groups. At an environmentally relevant concentration of 10 mg/L, Suwannee River humic acid (used as a model dissolved organic matter) alone had little effect on the dehydrochlorination of TeCA. However, it could inhibit the catalytic efficiency of the GO/RGO materials by coating on their surface and thus, decreasing the adsorption affinity of these materials for TeCA. The findings further underline the potentially important impacts of nanomaterials on contaminant fate and effects in the environment.

  18. Differential genotoxic and epigenotoxic effects of graphene family nanomaterials (GFNs) in human bronchial epithelial cells.

    PubMed

    Chatterjee, Nivedita; Yang, JiSu; Choi, Jinhee

    2016-03-01

    The widespread applications of graphene family nanomaterials (GFNs) raised the considerable concern over human health and environment. The cyto-genotoxic potentiality of GFNs has attracted much more attention, albeit the potential effects on the cellular epigenome remain largely unknown. The effects of GFNs on cellular genome were evaluated with single and double stranded DNA damage and DNA repair gene expressions while the effects on epigenome was accomplished by addressing the global DNA methylation and expression of DNA methylation machineries at non-cytotoxic to moderately cytotoxic doses in in vitro system. We used five different representatives of GFNs-pristine (GNP-Prist), carboxylated (GNP-COOH) and aminated (GNP-NH2) graphene nanoplatelets as well as single layer (SLGO) and few layer (FLGO) graphene oxide. The order of single stranded DNA damage was observed as GNP-Prist ≥ GNP-COOH>GNP-NH2≥FLGO>SLGO at 10mg/L and marked dose dependency was found in SLGO. The GFNs possibly caused genotoxicity by affecting nucleotide excision repair and non-homologus end joining repair systems. Besides, dose dependent increase in global DNA methylation (hypermethylation) were observed in SLGO/FLGO exposure and conversely, GNPs treatment caused hypomethylation following the order as GNP-COOH>GNP-NH2 ≥ GNP-Prist. The decrements of DNA methyltransferase (DNMT3B gene) and methyl-CpG binding domain protein (MBD1) genes were probably the cause of global hypomethylation induced by GNPs. Conversely, the de novo methylation through the up-regulation of DNMT3B and MBD1 genes gave rise to the global DNA hypermethylation in SLGO/FLGO treated cells. In general, the GFNs induced genotoxicity and alterations of global DNA methylation exhibited compounds type specificity with differential physico-chemical properties. Taken together, our study suggests that the GFNs could cause more subtle changes in gene expression programming by modulating DNA methylation status and this information

  19. Graphene oxide nanoribbons as nanomaterial for bone regeneration: Effects on cytotoxicity, gene expression and bactericidal effect.

    PubMed

    Ricci, R; Leite, N C S; da-Silva, N S; Pacheco-Soares, C; Canevari, R A; Marciano, F R; Webster, T J; Lobo, A O

    2017-09-01

    Graphene oxide nanoribbons (O-GNR) surges as an interesting nanomaterial for biomedical applications due to feasibility to incorporate functional groups and possible bactericidal properties. Herein, high concentrations of O-GNR were biologically evaluated using human osteoblast cells and gram positive and negative bacteria. Briefly, our goal were to evaluate: (1) synthetic pathway, (2) characterization and (3) effects of O-GNR composition and structural factors as a new approach for biomedical applications. For this, O-GNR were produced combining chemical vapor deposition and oxygen plasma treatment of multiwalled carbon nanotubes. Then, we analyzed the bioactivity, cell viability, osteogenic differentiation, matrix mineralization, mRNA levels of the five genes related direct to bone repair and bactericidal effect of high concentrations of O-GNR (10μgmL(-1), 100μgmL(-1), 200μgmL(-1) and 300μgmL(-1)). Impressively, O-GNR showed no cytotoxic effects up to a concentration of 100μgmL(-1) and no gene expression alteration when used in its dose. We also observed that S. aureus and E. coli bacteria are susceptible to damage when incubated with 100μgmL(-1) of O-GNR, showing approximately 50% of bacterial death. We consider that O-GNR displays attractive properties when used at a suitable dose, displaying bactericidal effect and apparently lacking to cause damages in the bone repair process. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Graphene-Based Nanomaterials as Efficient Peroxidase Mimetic Catalysts for Biosensing Applications: An Overview.

    PubMed

    Garg, Bhaskar; Bisht, Tanuja; Ling, Yong-Chien

    2015-08-04

    "Artificial enzymes", a term coined by Breslow for enzyme mimics is an exciting and promising branch of biomimetic chemistry aiming to imitate the general and essential principles of natural enzymes using a variety of alternative materials including heterogeneous catalysts. Peroxidase enzymes represent a large family of oxidoreductases that typically catalyze biological reactions with high substrate affinity and specificity under relatively mild conditions and thus offer a wide range of practical applications in many areas of science. The increasing understanding of general principles as well as intrinsic drawbacks such as low operational stability, high cost, difficulty in purification and storage, and sensitivity of catalytic activity towards atmospheric conditions of peroxidases has triggered a dynamic field in nanotechnology, biochemical, and material science that aims at joining the better of three worlds by combining the concept adapted from nature with the processability of catalytically active graphene-based nanomaterials (G-NMs) as excellent peroxidase mimetic catalysts. This comprehensive review discusses an up-to-date synthesis, kinetics, mechanisms, and biosensing applications of a variety of G-NMs that have been explored as promising catalysts to mimic natural peroxidases.

  1. Electrochemical and spectroscopic studies of ssDNA damage induced by hydrogen peroxide using graphene based nanomaterials.

    PubMed

    Berghian-Grosan, Camelia; Biris, Alexandru Radu; Coros, Maria; Pogacean, Florina; Pruneanu, Stela

    2015-06-01

    The oxidative damage of deoxyribonucleic acid (DNA) has been intensively studied due to its role in the occurrence of some diseases. The hydrogen peroxide (H2O2) is one of the reactive oxygen species (ROS). It can induce oxidation of DNA bases, sugar lesions or DNA strand breaks. The Pt/Gr-Au-3 modified electrode was employed for the analysis of four ssDNA samples: single-stranded DNA (ssDNA), ssDNA pre-treated with hydrogen peroxide (ssDNA-H2O2), ssDNA pre-treated with graphene-gold nanoparticles (ssDNA-Gr-Au) and ssDNA-Gr-Au complex pre-treated with hydrogen peroxide (ssDNA-Gr-Au-H2O2). By monitoring the changes of the purine oxidation peaks currents, we obtained valuable information about the damage induced by the hydrogen peroxide onto the un-treated or graphene pre-treated ssDNA and also about the interaction between ssDNA and graphene-based nanomaterial. The FTIR analysis has been also used to obtain information about the ssDNA damage. These findings allowed us to prove the utility of graphene-based nanomaterials (mainly Gr-Au-3) not only for the investigation of the oxidative damage induced by a non-radical oxidant, but also for the determination of the type of interaction between ssDNA and graphene surface. The stability of the ssDNA-Gr-Au-3 complex against the damage induced by H2O2, in the absence of reduced transition metals, was also established. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Cytotoxicity assessment of graphene-based nanomaterials on human dental follicle stem cells.

    PubMed

    Olteanu, Diana; Filip, Adriana; Socaci, Crina; Biris, Alexandru Radu; Filip, Xenia; Coros, Maria; Rosu, Marcela Corina; Pogacean, Florina; Alb, Camelia; Baldea, Ioana; Bolfa, Pompei; Pruneanu, Stela

    2015-12-01

    Graphene-oxide (GO) and its most encountered derivatives, thermally reduced graphene oxide (TRGO) and nitrogen-doped graphene (N-Gr), were synthesized and structurally characterized by spectroscopic techniques, like Raman and (13)C MAS solid state NMR. Several biological effects (cytotoxicity, oxidative stress induction, and cellular and mithocondrial membrane alterations) induced by such graphene-based materials on human dental follicle stem cells were investigated. Graphene oxide shows the lowest cytotoxic effect, followed by the nitrogen-doped graphene, while thermally reduced graphene oxide exhibits high cytotoxic effects. Graphene oxide induces oxidative stress without causing cell membrane damage. Nitrogen-doped graphene shows a slight antioxidant activity; however, at high doses (20 and 40 μg/ml) it causes membrane damage. Both graphene oxide and nitrogen-doped graphene seem to be valuable candidates for usage in dental nanocomposites. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Removal of graphene oxide nanomaterials from aqueous media via coagulation: Effects of water chemistry and natural organic matter.

    PubMed

    Duan, Lin; Hao, Rongjie; Xu, Zhu; He, Xizhen; Adeleye, Adeyemi S; Li, Yao

    2017-02-01

    With the increasing use of graphene oxide (GO) nanomaterials, its possible environmental release and human effects have received much attention. As GO may enter drinking or wastewater treatment systems like other carbonaceous nanomaterials, and have potential impact on human and/or environmental health, its removal efficiency during water treatment is important and requires investigation. In this study, the removal efficiency of GO during water treatment procedure via coagulation was evaluated, and the effects of solution chemistry and natural organic matter on the coagulation-based removal of GO nanomaterials were investigated. The results indicate that the removal efficiency of GO with alum coagulation can reach 80% with 20 mg/L alum dosage at neutral pH, and will not change significantly with higher concentration of alum. The coagulation mechanism and efficiency were strongly affected by the Al species in aqueous phase, which are controlled by pH. Co-existing cations (e.g. Na) may have minimal effect on GO removal efficiency, and the presence of humic acid (HA) suppresses coagulation remarkably at alum concentrations below 40 mg/L. The results from this study provide critical information for predicting the removal efficiency of GO nanomaterials during alum coagulation phase of water treatment procedure.

  4. Differential cytotoxicity and internalization of graphene family nanomaterials in myocardial cells.

    PubMed

    Contreras-Torres, Flavio F; Rodríguez-Galván, Andrés; Guerrero-Beltrán, Carlos E; Martínez-Lorán, Erick; Vázquez-Garza, Eduardo; Ornelas-Soto, Nancy; García-Rivas, Gerardo

    2017-04-01

    Given the well-known physical properties of graphene oxide (GO), numerous applications for this novel nanomaterial have been recently envisioned to improve the performance of biomedical devices. However, the toxicological assessment of GO, which strongly depends on the used material and the studied cell line, is a fundamental task that needs to be performed prior to its use in biomedical applications. Therefore, the toxicological characterization of GO is still ongoing. This study contributes to this, aiming to synthesize and characterize GO particles and thus investigate their toxic effects in myocardial cells. Herein, GO particles were produced from graphite using the Tour method and subsequent mild reduction was carried out to obtain low-reduced GO (LRGO) particles. A qualitative analysis of the viability, cellular uptake, and internalization of particles was carried out using GO (~54% content of oxygen) and LRGO (~37% content of oxygen) and graphite. GO and LRGO reduce the viability of cardiac cells at IC50 of 652.1±1.2 and 129.4±1.2μg/mL, respectively. This shows that LRGO particles produce a five-fold increase in cytotoxicity when compared to GO. The cell uptake pattern of GO and LRGO particles demonstrated that cardiac cells retain a similar complexity to control cells. Morphological alterations examined with electron microscopy showed that internalization by GO and LRGO-treated cells (100μg/mL) occurred affecting the cell structure. These results suggest that the viability of H9c2 cells can be associated with the surface chemistry of GO and LRGO, as defined by the amount of oxygen functionalities, the number of graphitic domains, and the size of particles. High angle annular dark-field scanning transmission electron microscopy, dynamic light-scattering, Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopies were used to characterize the as-prepared materials.

  5. The role of graphene oxide and graphene oxide-based nanomaterials in the removal of pharmaceuticals from aqueous media: a review.

    PubMed

    Khan, Ayub; Wang, Jian; Li, Jun; Wang, Xiangxue; Chen, Zhongshan; Alsaedi, Ahmed; Hayat, Tasawar; Chen, Yuantao; Wang, Xiangke

    2017-03-01

    In this review paper, the ill effects of pharmaceuticals (PhAs) on the environment and their adsorption on graphene oxide (GO) and graphene oxide-based (GO-based) nanomaterials have been summarised and discussed. The adsorption of prominent PhAs discussed herein includes beta-blockers (atenolol and propranolol), antibiotics (tetracycline, ciprofloxacin and sulfamethoxazole), pharmaceutically active compounds (carbamazepine) and analgesics such as diclofenac. The adsorption of PhAs strictly depends upon the experimental conditions such as pH, adsorbent and adsorbate concentrations, temperature, ionic strength, etc. To understand the adsorption mechanism and feasibility of the adsorption process, the adsorption isotherms, thermodynamics and kinetic studies were also considered. Except for some cases, GO and its derivatives show excellent adsorption capacities for PhAs, which is crucial for their applications in the environmental pollution cleanup.

  6. Envelopment-Internalization Synergistic Effects and Metabolic Mechanisms of Graphene Oxide on Single-Cell Chlorella vulgaris Are Dependent on the Nanomaterial Particle Size.

    PubMed

    Ouyang, Shaohu; Hu, Xiangang; Zhou, Qixing

    2015-08-19

    The interactions between nanomaterials and cells are fundamental in biological responses to nanomaterials. However, the size-dependent synergistic effects of envelopment and internalization as well as the metabolic mechanisms of nanomaterials have remained unknown. The nanomaterials tested here were larger graphene oxide nanosheets (GONS) and small graphene oxide quantum dots (GOQD). GONS intensively entrapped single-celled Chlorella vulgaris, and envelopment by GONS reduced the cell permeability. In contrast, GOQD-induced remarkable shrinkage of the plasma membrane and then enhanced cell permeability through strong internalization effects such as plasmolysis, uptake of nanomaterials, an oxidative stress increase, and inhibition of cell division and chlorophyll biosynthesis. Metabolomics analysis showed that amino acid metabolism was sensitive to nanomaterial exposure. Shrinkage of the plasma membrane is proposed to be linked to increases in the isoleucine levels. The inhibition of cell division and chlorophyll a biosynthesis was associated with decreases in aspartic acid and serine, the precursors of chlorophyll a. The increases in mitochondrial membrane potential loss and oxidative stress were correlated with an increase in linolenic acid. The above metabolites can be used as indicators of the corresponding biological responses. These results enhance our systemic understanding of the size-dependent biological effects of nanomaterials.

  7. Few-layer graphene shells and nonmagnetic encapsulates: a versatile and nontoxic carbon nanomaterial.

    PubMed

    Bachmatiuk, Alicja; Mendes, Rafael G; Hirsch, Cordula; Jähne, Carsten; Lohe, Martin R; Grothe, Julia; Kaskel, Stefan; Fu, Lei; Klingeler, Rüdiger; Eckert, Jürgen; Wick, Peter; Rümmeli, Mark H

    2013-12-23

    In this work a simple and scalable approach to coat nonmagnetic nanoparticles with few-layer graphene is presented. In addition, the easy processing of such nanoparticles to remove their core, leaving only the 3D graphene nanoshell, is demonstrated. The samples are comprehensively characterized, as are their versatility in terms of functionalization and as a material for electrochemical storage. Indeed, these 3D graphene nanostructures are easily functionalized much as is found with carbon nanotubes and planar graphene. Electrochemical investigations indicate these nanostructures are promising for stable long-life battery applications. Finally, initial toxicological investigations suggest no acute health risk from these 3D graphene nanostructures.

  8. A Critical Review of Glucose Biosensors Based on Carbon Nanomaterials: Carbon Nanotubes and Graphene

    PubMed Central

    Zhu, Zhigang; Garcia-Gancedo, Luis; Flewitt, Andrew J.; Xie, Huaqing; Moussy, Francis; Milne, William I.

    2012-01-01

    There has been an explosion of research into the physical and chemical properties of carbon-based nanomaterials, since the discovery of carbon nanotubes (CNTs) by Iijima in 1991. Carbon nanomaterials offer unique advantages in several areas, like high surface-volume ratio, high electrical conductivity, chemical stability and strong mechanical strength, and are thus frequently being incorporated into sensing elements. Carbon nanomaterial-based sensors generally have higher sensitivities and a lower detection limit than conventional ones. In this review, a brief history of glucose biosensors is firstly presented. The carbon nanotube and grapheme-based biosensors, are introduced in Sections 3 and 4, respectively, which cover synthesis methods, up-to-date sensing approaches and nonenzymatic hybrid sensors. Finally, we briefly outline the current status and future direction for carbon nanomaterials to be used in the sensing area. PMID:22778628

  9. Tapered optical fiber coated with graphene based nanomaterials for measurement of ethanol concentrations in water

    NASA Astrophysics Data System (ADS)

    Girei, Saad H.; Shabaneh, Atafat A.; Ngee-Lim, Hong; Hamidon, Mohd N.; Mahdi, Mohd A.; Yaacob, Mohd H.

    2015-06-01

    Tapered optical fibers coated with graphene and graphene oxide (GO) as the active layer for ethanol sensing were reported. The multimode optical fiber with 125 µm diameter was tapered to 40 µm diameter to enhance the sensitivity. Graphene and GO thin films were characterized using a scanning electron microscopy, Raman spectroscopy and ultraviolet-visible (UV-Vis) spectroscopy. The absorbance properties of the developed sensors increased when exposed to ethanol due to the change of light in the evanescent field. The sensing results indicated that the GO-coated sensor showed better performance with absorbance change of 80 % towards ethanol concentration of 5 % when compared to graphene-coated sensor with 40 % absorbance change towards ethanol with similar concentrations. The reliable response of the graphene and GO-coated on tapered fibers for detecting ethanol concentrations was achieved at room temperature.

  10. Extended Simulations of Graphene Growth with Updated Rate Coefficients

    SciTech Connect

    Whitesides, R; You, X; Frenklach, M

    2010-03-18

    New simulations of graphene growth in flame environments are presented. The simulations employ a kinetic Monte Carlo (KMC) algorithm coupled to molecular mechanics (MM) geometry optimization to track individual graphenic species as they evolve. Focus is given to incorporation of five-member rings and resulting curvature and edge defects. The model code has been re-written to be more computationally efficient enabling a larger set of simulations to be run, decreasing stochastic fluctuations in the averaged results. The model also includes updated rate coefficients for graphene edge reactions recently published in the literature. The new simulations are compared to results from the previous model as well as to hydrogen to carbon ratios recorded in experiment and calculated with alternate models.

  11. Synthesis of Extended Atomically Perfect Zigzag Graphene - Boron Nitride Interfaces

    PubMed Central

    Drost, Robert; Kezilebieke, Shawulienu; M. Ervasti, Mikko; Hämäläinen, Sampsa K.; Schulz, Fabian; Harju, Ari; Liljeroth, Peter

    2015-01-01

    The combination of several materials into heterostructures is a powerful method for controlling material properties. The integration of graphene (G) with hexagonal boron nitride (BN) in particular has been heralded as a way to engineer the graphene band structure and implement spin- and valleytronics in 2D materials. Despite recent efforts, fabrication methods for well-defined G-BN structures on a large scale are still lacking. We report on a new method for producing atomically well-defined G-BN structures on an unprecedented length scale by exploiting the interaction of G and BN edges with a Ni(111) surface as well as each other. PMID:26584674

  12. Diffusion and separation of CH4/N2 in pillared graphene nanomaterials: A molecular dynamics investigation

    NASA Astrophysics Data System (ADS)

    Zhou, Sainan; Lu, Xiaoqing; Wu, Zhonghua; Jin, Dongliang; Guo, Chen; Wang, Maohuai; Wei, Shuxian

    2016-09-01

    Diffusion and separation of CH4/N2 in pillared graphene were investigated by molecular dynamics. The pillared graphene with (6, 6) carbon nanotube (CNT) exhibited the higher diffusion and selectivity of CH4 over N2 than that with (7, 7) CNT due to the cooperative effect of pore topological characteristics and interaction energy. The stronger interaction facilitated CH4 to enter CNT prior to N2, and higher pressure promoted CH4 to pass CNT more easily. The relative concentrations profiles showed that CH4 reached equilibrium state faster than N2 at low pressure. Our results highlight potential use of pillared graphene in gas purification and separation.

  13. Functionalized graphene nanomaterials: new insight into direct exfoliation of graphite with supramolecular polymers

    NASA Astrophysics Data System (ADS)

    Cheng, Chih-Chia; Chang, Feng-Chih; Wang, Jui-Hsu; Chen, Jem-Kun; Yen, Ying-Chieh; Lee, Duu-Jong

    2015-12-01

    A novel urea-cytosine end-capped polypropylene glycol (UrCy-PPG) can self-assemble into a long-range ordered lamellar microstructure on the surface of graphene, due to the strong specific interactions between UrCy-PPG and graphene. In addition, the graphene composite produced exhibits a high conductivity (~1093 S m-1) with a dramatic thermo-responsive ON/OFF resistance-switching behavior (10 consecutive cycles).A novel urea-cytosine end-capped polypropylene glycol (UrCy-PPG) can self-assemble into a long-range ordered lamellar microstructure on the surface of graphene, due to the strong specific interactions between UrCy-PPG and graphene. In addition, the graphene composite produced exhibits a high conductivity (~1093 S m-1) with a dramatic thermo-responsive ON/OFF resistance-switching behavior (10 consecutive cycles). Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07076g

  14. Biofabrication of a novel biomolecule-assisted reduced graphene oxide: an excellent biocompatible nanomaterial.

    PubMed

    Zhang, Xi-Feng; Gurunathan, Sangiliyandi

    Graphene has been shown much interest, both in academics and industry due to its extraordinary physical, chemical, and biological proprieties. It shows great promises in biotechnological and biomedical applications as an antibacterial and anticancer agent, nanocarrier, sensor, etc. However, many studies demonstrated the toxicity of graphene in several cell lines, which is an obstacle to its use in biomedical applications. In this study, to improve the biocompatibility of graphene, we used nicotinamide (NAM) as a reducing and stabilizing agent to catalyze the reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The resulted smaller-sized GO (NAM-rGO) showed excellent biocompatibility with mouse embryonic fibroblast cells, evidenced by various cellular assays. Furthermore, NAM-rGO had no effect on mitochondrial membrane permeability and caspase-3 activity compared to GO. Reverse transcription polymerase chain reaction analysis allowed us to identify the molecular mechanisms responsible for NAM-rGO-induced biocompatibility. NAM-rGO significantly induced the expression of genes encoding tight junction proteins (TJPs) such as zona occludens-1 (Tjp1) and claudins (Cldn3) without any effect on the expression of cytoskeleton proteins. Furthermore, NAM-rGO enhances the expression of alkaline phosphatase (ALP) gene, and it does this in a time-dependent manner. Overall, our study depicted the molecular mechanisms underlying NAM-rGO biocompatibility depending on upregulation of TJPs and ALP. This potential quality of graphene could be used in diverse applications including tissue regeneration and tissue engineering.

  15. Biofabrication of a novel biomolecule-assisted reduced graphene oxide: an excellent biocompatible nanomaterial

    PubMed Central

    Zhang, Xi-Feng; Gurunathan, Sangiliyandi

    2016-01-01

    Graphene has been shown much interest, both in academics and industry due to its extraordinary physical, chemical, and biological proprieties. It shows great promises in biotechnological and biomedical applications as an antibacterial and anticancer agent, nanocarrier, sensor, etc. However, many studies demonstrated the toxicity of graphene in several cell lines, which is an obstacle to its use in biomedical applications. In this study, to improve the biocompatibility of graphene, we used nicotinamide (NAM) as a reducing and stabilizing agent to catalyze the reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The resulted smaller-sized GO (NAM-rGO) showed excellent biocompatibility with mouse embryonic fibroblast cells, evidenced by various cellular assays. Furthermore, NAM-rGO had no effect on mitochondrial membrane permeability and caspase-3 activity compared to GO. Reverse transcription polymerase chain reaction analysis allowed us to identify the molecular mechanisms responsible for NAM-rGO-induced biocompatibility. NAM-rGO significantly induced the expression of genes encoding tight junction proteins (TJPs) such as zona occludens-1 (Tjp1) and claudins (Cldn3) without any effect on the expression of cytoskeleton proteins. Furthermore, NAM-rGO enhances the expression of alkaline phosphatase (ALP) gene, and it does this in a time-dependent manner. Overall, our study depicted the molecular mechanisms underlying NAM-rGO biocompatibility depending on upregulation of TJPs and ALP. This potential quality of graphene could be used in diverse applications including tissue regeneration and tissue engineering. PMID:27994461

  16. Potentiating effect of graphene nanomaterials on aromatic environmental pollutant-induced cytochrome P450 1A expression in the topminnow fish hepatoma cell line PLHC-1.

    PubMed

    Lammel, Tobias; Boisseaux, Paul; Navas, José M

    2015-09-01

    Graphene and its derivatives are an emerging class of carbon nanomaterial with great potential for a broad range of industrial and consumer applications. However, their increasing production and use is expected to result in release of nano-sized graphene platelets into the environment, where they may interact with chemical pollutants modifying their fate and toxic potential. The objective of this study was to assess whether graphene nanoplatelets can act as vector for aromatic environmental pollutants increasing their cellular uptake and associated hazardous effects in vitro. For this purpose, cell cultures of the topminnow fish (Poeciliopsis lucida) hepatoma cell line PLHC-1 were simultaneously (and successively) exposed to graphene nanoplatelets (graphene oxide (GO) or carboxyl graphene (CXYG)) and an aryl hydrocarbon receptor (AhR) agonist (β-naphthoflavone (β-NF), benzo(k)fluoranthene (BkF) or 3,3',4,4',5,5'-hexachlorobiphenyl (PCB169)). Following exposure cytochrome P450 1A (Cyp1A) induction was assessed by measuring cyp1A mRNA expression levels using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Cyp1A-dependent ethoxyresorufin-O-deethylase (EROD) activity. It was observed that pre- and co-exposure of cells to GO and CXYG nanoplatelets had a potentiating effect on β-NF, BkF, and PCB169-dependent Cyp1A induction suggesting that graphene nanoplatelets increase the effective concentration of AhR agonists by facilitating their passive diffusion into the cells by damaging the cells' plasma membrane and/or by transporting them over the plasma membrane via a Trojan horse-like mechanism. The results demonstrate the existence of combination effects between nanomaterials and environmental pollutants and stress the importance of considering these effects when evaluating their respective hazard.

  17. Anomalous Dirac point transport due to extended defects in bilayer graphene.

    PubMed

    Shallcross, Sam; Sharma, Sangeeta; Weber, Heiko B

    2017-08-24

    Charge transport at the Dirac point in bilayer graphene exhibits two dramatically different transport states, insulating and metallic, that occur in apparently otherwise indistinguishable experimental samples. We demonstrate that the existence of these two transport states has its origin in an interplay between evanescent modes, that dominate charge transport near the Dirac point, and disordered configurations of extended defects in the form of partial dislocations. In a large ensemble of bilayer systems with randomly positioned partial dislocations, the distribution of conductivities is found to be strongly peaked at both the insulating and metallic limits. We argue that this distribution form, that occurs only at the Dirac point, lies at the heart of the observation of both metallic and insulating states in bilayer graphene.In seemingly indistinguishable bilayer graphene samples, two distinct transport regimes, insulating and metallic, have been identified experimentally. Here, the authors demonstrate that these two states originate from the interplay between extended defects and evanescent modes at the Dirac point.

  18. Interactions of Graphene Oxide Nanomaterials with Natural Organic Matter and Metal Oxide Surfaces

    EPA Science Inventory

    Interactions of graphene oxide (GO) with silica surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Both GO deposition and release were monitored on silica- and poly-l-lysine (PLL) coated surfaces as a function of GO concentration a...

  19. Interactions of Graphene Oxide Nanomaterials with Natural Organic Matter and Metal Oxide Surfaces

    EPA Science Inventory

    Interactions of graphene oxide (GO) with silica surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Both GO deposition and release were monitored on silica- and poly-l-lysine (PLL) coated surfaces as a function of GO concentration a...

  20. Biological Interactions of Graphene-Family Nanomaterials – An Interdisciplinary Review

    PubMed Central

    Sanchez, Vanesa C.; Jachak, Ashish; Hurt, Robert H.; Kane, Agnes B.

    2011-01-01

    Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. Related materials include few-layer-graphene (FLG), ultrathin graphite, graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanosheets (GNS). This review proposes a systematic nomenclature for this set of “Graphene-Family Nanomaterials” (GFNs) and discusses specific materials properties relevant for biomolecular and cellular interactions. The article discusses several unique modes of interaction between GFNs and nucleic acids, lipid bilayers, and conjugated small molecule drugs and dyes. Some GFNs are produced as dry powders using thermal exfoliation, and in these cases inhalation is a likely route of human exposure. Some GFNs have aerodynamic sizes that can lead to inhalation and substantial deposition in the human respiratory tract, which may impair lung defense and clearance leading to formation of granulomas and lung fibrosis. The limited literature on in vitro toxicity suggests that GFNs can be either benign or toxic to cells, and it is hypothesized that the biological response will vary across the material family depending on layer number, lateral size, stiffness, hydrophobicity, surface functionalization, and dose. Generation of reactive oxygen species (ROS) in target cells is a potential mechanism for toxicity, although the extremely high hydrophobic surface area of some GFNs may also lead to significant interactions with membrane lipids leading to direct physical toxicity or adsorption of biological molecules leading to indirect toxicity. Limited in vivo studies demonstrate systemic biodistribution and biopersistence of GFNs following intravenous delivery. Similar to other smooth, continuous, biopersistent implants or foreign bodies, GFNs have the potential to induce foreign body tumors. Long-term adverse health impacts must be considered in design of GFNs for drug delivery, tissue

  1. Cuprous Sulfide/Reduced Graphene Oxide Hybrid Nanomaterials: Solvothermal Synthesis and Enhanced Electrochemical Performance

    NASA Astrophysics Data System (ADS)

    He, Zhanjun; Zhu, Yabo; Xing, Zheng; Wang, Zhengyuan

    2016-01-01

    The cuprous sulfide nanoparticles (CuS NPs)-decorated reduced graphene oxide (rGO) nanocomposites have been successfully prepared via a facile and efficient solvothermal synthesis method. Scanning electron microscopy and transmission electron microscopy images demonstrated that CuS micronspheres composed of nanosheets and distributed on the rGO layer in well-monodispersed form. Fourier-transform infrared spectroscopy analyses and x-ray photoelectron spectroscopy showed that graphene oxide (GO) had been reduced to rGO. The electrochemical performances of CuS/rGO nanocomposites were investigated by cyclic voltammetry and charge/discharge techniques, which showed that the specific capacitance of CuS/rGO nanocomposites was enhanced because of the introduction of rGO.

  2. Two-dimensional collagen-graphene as colloidal templates for biocompatible inorganic nanomaterial synthesis.

    PubMed

    Kumari, Divya; Sheikh, Lubna; Bhattacharya, Soumya; Webster, Thomas J; Nayar, Suprabha

    2017-01-01

    In this study, natural graphite was first converted to collagen-graphene composites and then used as templates for the synthesis of nanoparticles of silver, iron oxide, and hydroxyapatite. X-ray diffraction did not show any diffraction peaks of graphene in the composites after inorganic nucleation, compared to the naked composite which showed (002) and (004) peaks. Scanning electron micrographs showed lateral gluing/docking of these composites, possibly driven by an electrostatic attraction between the positive layers of one stack and negative layers of another, which became distorted after inorganic nucleation. Docking resulted in single layer-like characteristics in certain places, as seen under transmission electron microscopy, but sp(2)/sp(3) ratios from Raman analysis inferred three-layer composite formation. Strain-induced folding of these layers into uniform clusters at the point of critical nucleation, revealed beautiful microstructures under scanning electron microscopy. Lastly, cell viability studies using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed the highest cell viability for the collagen-graphene-hydroxyapatite composites. In this manner, this study provided - to the field of nanomedicine - a new process for the synthesis of several nanoparticles (with low toxicity) of high interest for numerous medical applications.

  3. Two-dimensional collagen-graphene as colloidal templates for biocompatible inorganic nanomaterial synthesis

    PubMed Central

    Kumari, Divya; Sheikh, Lubna; Bhattacharya, Soumya; Webster, Thomas J; Nayar, Suprabha

    2017-01-01

    In this study, natural graphite was first converted to collagen-graphene composites and then used as templates for the synthesis of nanoparticles of silver, iron oxide, and hydroxyapatite. X-ray diffraction did not show any diffraction peaks of graphene in the composites after inorganic nucleation, compared to the naked composite which showed (002) and (004) peaks. Scanning electron micrographs showed lateral gluing/docking of these composites, possibly driven by an electrostatic attraction between the positive layers of one stack and negative layers of another, which became distorted after inorganic nucleation. Docking resulted in single layer-like characteristics in certain places, as seen under transmission electron microscopy, but sp2/sp3 ratios from Raman analysis inferred three-layer composite formation. Strain-induced folding of these layers into uniform clusters at the point of critical nucleation, revealed beautiful microstructures under scanning electron microscopy. Lastly, cell viability studies using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed the highest cell viability for the collagen-graphene-hydroxyapatite composites. In this manner, this study provided – to the field of nanomedicine – a new process for the synthesis of several nanoparticles (with low toxicity) of high interest for numerous medical applications. PMID:28553102

  4. A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

    PubMed Central

    Comini, Elisabetta; Kholmanov, Iskandar; Ponzoni, Andrea; Sberveglieri, Veronica; Poli, Nicola; Faglia, Guido; Sberveglieri, Giorgio

    2016-01-01

    Summary A hybrid nanostructure based on reduced graphene oxide and ZnO has been obtained for the detection of volatile organic compounds. The sensing properties of the hybrid structure have been studied for different concentrations of ethanol and acetone. The response of the hybrid material is significantly higher compared to pristine ZnO nanostructures. The obtained results have shown that the nanohybrid is a promising structure for the monitoring of environmental pollutants and for the application of breath tests in assessment of exposure to volatile organic compounds. PMID:27826516

  5. Aerosol synthesis and application of folded graphene-based materials

    NASA Astrophysics Data System (ADS)

    Chen, Yantao; Wang, Zhongying; Qiu, Yang

    2015-12-01

    Graphene oxide colloid has been widely used in the synthesis of various graphene-based materials. Graphene oxide sheets, with a low bending rigidity, can be folded when assembled in aqueous phase. A simple but industrial scalable way, aerosol processing, can be used to fabricate folded graphene-based materials. These folded materials can carry various cargo materials and be used in different applications such as time-controlled drug release, medical imaging enhancement, catalyst support and energy related areas. The aerosol synthesis of folded graphene-based materials can also be easily extended to fabricate hybrid nanomaterials without any complicated chemistries.

  6. Photocatalytic degradation of commercially sourced naphthenic acids by TiO2-graphene composite nanomaterial.

    PubMed

    Liu, Juncheng; Wang, Lin; Tang, Jingchun; Ma, Jianli

    2016-04-01

    Naphthenic acids (NAs) are a major contributor to the toxicity in oil sands process-affected water (OSPW), which is produced by hot water extraction of bitumen. NAs are extremely difficult to be degraded due to its complex ring and side chain structure. Photocatalysis is recognized as a promising technology in the removal of refractory organic pollutants. In this work, TiO2-graphene (P25-GR) composites were synthesized by means of solvothermal method. The results showed that P25-GR composite exhibited better photocatalytic activity than pure P25. The removal efficiency of naphthenic acids in acid solution was higher than that in neutral and alkaline solutions. It was the first report ever known on the photodegradation of NAs based on graphene, and this process achieved a higher removal rate than other photocatalysis degradation of NAs in a shorter reaction time. LC/MS analysis showed that macromolecular NAs (carbon number 17-22, z value -2) were easy to be degraded than the micromolecular ones (carbon number 11-16, z value -2). Furthermore, the reactive oxygen species that play the main role in the photocatalysis system were studied. It was found that holes and ·OH were the main reactive species in the UV/P25-GR photocatalysis system. Given the high removal efficiency of refractory organic pollutants and the short degradation time, photodegradation based on composite catalysts has a broad and practical prospect. The study on the photodegradation of commercially sourced NAs may provide a guidance for the degradation of OSPW NAs by this method.

  7. Application of graphene-based nanomaterials as novel cathode catalysts for improving power generation in single chamber microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Valipour, Alireza; Ayyaru, Sivasankaran; Ahn, Youngho

    2016-09-01

    The low catalytic activity, limited resources, complexity and costs, and non-environmentally friendly nature are key factors limiting the application of non-precious metals and their composites at the cathode in microbial fuel cells (MFCs). This study evaluated the feasibility of graphene-based nanomaterials (RGOHI-AcOH vs. RGO/Ni nanoparticle composite) as novel cathode catalysts in single chamber air-cathode MFCs. A series of MFCs with different catalyst loadings were produced. The electrochemical behavior of the MFCs were evaluated by cyclic voltammetry (CV) and impedance spectroscopy (EIS). As a result, the MFCs with the RGOHI-AcOH cathodes showed greater maximum power densities (>37%) than those with the RGO/Ni nanoparticle cathodes. In the MFCs, the highest maximum power density of 1683 ± 23 mW/m2 (CE = 72 ± 3%), which covers 77% of that estimated for Pt/C (2201 ± 45 mW/m2, CE = 81 ± 4%), was obtained from the double loading RGOHI-AcOH cathodes. Among the MFCs with the RGO/Ni nanoparticle composite cathodes, those loaded with a double catalyst (1015 ± 28 mW/m2, CE = 70 ± 2%) showed better power performance than the others. Both CV and EIS showed good agreement with the MFC results. This study suggests that the RGOHI-AcOH cathode, particularly with a double catalyst loading, is promising for sustainable low-cost green materials, stable power generation and the long-term operation of MFCs.

  8. Cation-Inhibited Transport of Graphene Oxide Nanomaterials in Saturated Porous Media: The Hofmeister Effects.

    PubMed

    Xia, Tianjiao; Qi, Yu; Liu, Jing; Qi, Zhichong; Chen, Wei; Wiesner, Mark R

    2017-01-17

    Transport of negatively charged nanoparticles in porous media is largely affected by cations. To date, little is known about how cations of the same valence may affect nanoparticle transport differently. We observed that the effects of cations on the transport of graphene oxide (GO) and sulfide-reduced GO (RGO) in saturated quartz sand obeyed the Hofmeister series; that is, transport-inhibition effects of alkali metal ions followed the order of Na(+) < K(+) < Cs(+), and those of alkaline earth metal ions followed the order of Mg(2+) < Ca(2+) < Ba(2+). With batch adsorption experiments and microscopic data, we verified that cations having large ionic radii (and thus being weakly hydrated) interacted with quartz sand and GO and RGO more strongly than did cations of small ionic radii. In particular, the monovalent Cs(+) and divalent Ca(2+) and Ba(2+), which can form inner-sphere complexes, resulted in very significant deposition of GO and RGO via cation bridging between quartz sand and GO and RGO, and possibly via enhanced straining, due to the enhanced aggregation of GO and RGO from cation bridging. The existence of the Hofmeister effects was further corroborated with the interesting observation that cation bridging was more significant for RGO, which contained greater amounts of carboxyl and phenolic groups (i.e., metal-complexing moieties) than did GO. The findings further demonstrate that transport of nanoparticles is controlled by the complex interplay between nanoparticle surface functionalities and solution chemistry constituents.

  9. Energy gap of extended states in SiC-doped graphene nanoribbon: Ab initio calculations

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoshi; Wu, Yong; Li, Zhongyao; Gao, Yong

    2017-04-01

    The energy gap of extended states in zigzag graphene nanoribbons (ZGNRs) was examined on the basis of density-functional theory. In isolated ZGNRs, the energy gap is inversely proportional to the width of ribbon. It agrees well with the results from the Dirac equation in spin-unpolarized ZGNRs, although the considered ZGNRs have spin-polarized edges. However, the energy gap in SiC-doped ZGNRs cannot be modeled by effective width approximation. The doping also lifts the spin-degenerate of edge states and results in a metallic-like band structure near the Fermi level in SiC-doped ZGNRs. Our calculations may be helpful for understanding the origin of the reported single-channel ballistic transport in epitaxial graphene nanoribbons.

  10. In Situ Fabrication of CoS and NiS Nanomaterials Anchored on Reduced Graphene Oxide for Reversible Lithium Storage.

    PubMed

    Tan, Yingbin; Liang, Ming; Lou, Peili; Cui, Zhonghui; Guo, Xiangxin; Sun, Weiwei; Yu, Xuebin

    2016-06-15

    CoS and NiS nanomaterials anchored on reduced graphene oxide (rGO) sheets, synthesized via combination of hydrothermal with sulfidation process, are studied as high-capacity anode materials for the reversible lithium storage. The obtained CoS nanofibers and NiS nanoparticles are uniformly dispersed on rGO sheets without aggregation, forming the sheet-on-sheet composite structure. Such nanoarchitecture can not only facilitate ion/electron transport along the interfaces, but also effectively prevent metal-sulfide nanomaterials aggregation during the lithium reactions. Both the rGO-supported CoS nanofibers (NFs) and NiS nanoparticles (NPs) show superior lithium storage performance. In particular, the CoS NFs-rGO electrodes deliver the discharge capacity as high as 939 mA h g(-1) after the 100th cycle at 100 mA g(-1) with Coulombic efficiency above 98%. This strategy for construction of such composite structure can also synthesize other metal-sulfide-rGO nanomaterials for high-capacity lithium-ion batteries.

  11. [Provision of the population with sanitary-and-epidemiological wellbeing under conditions of extended use of nanomaterials and nanotechnologies].

    PubMed

    Onishchenko, G G

    2010-01-01

    As of now, work is ever increasingly and successfully proceeding on the development of nanotechnologies and promising nanomaterials. By 2015, the nanotechnology product market may be expected to amount to US$ 1.2-2.9 trillion. Nanotechnology as a set of methods for the controlled manipulation of material objects with the sizes of less than 100 nm makes it possible to use a substance with a traditional chemical composition to design structures in the nanometer range (nanomaterials) and to endow them with fundamentally new properties, such as unique mechanical strength, special spectral, electrical, magnetic, chemical, and biological characteristics. Among the main domains for applications of nanomaterials, we should now single out optics, power engineering, researches, wildlife conservation, etc. The specific physicochemical properties of nanomaterials suggest that they can be toxic to humans. That is the reason that society should be keenly aware of what the nanomaterials are. Despite the fact that nanomaterials have been already used worldwide for more than 10 years, none kind has been fully investigated for its safety in any country.

  12. Ferromagnetically coupled local moments along an extended line defect in graphene

    NASA Astrophysics Data System (ADS)

    White, Carter T.; Vasudevan, Smitha; Gunlycke, Daniel

    2011-03-01

    Recently an extended line defect was observed composed of octagonal and pentagonal carbon rings embedded in a graphene sheet [Nat. Nanotech. 5, 326 (2010)]. We report results of studies we have made of this defect using both first-principles and semi-empirical methods. Two types of boundary-localized states arising from the defect are identified. The first (second) type has eigenstates with wavefunctions that are anti- symmetric (symmetric) with respect to a mirror plane that is perpendicular to the graphene sheet and passes through the line defect center line. The boundary-localized anti-symmetric states are shown to be intimately connected to the zigzag edge states of semi-infinite graphene. They exhibit little dispersion along the defect line and lie close to the Fermi level giving rise to a spontaneous spin polarization along the defect once electron-electron interactions are included at the level of a mean field approximation to a Hubbard Model. Within this approach, symmetry requires that the principal moments couple ferromagnetically both along and across the line defect leading to approximately 2/3 more up than down spin electrons per defect repeat unit. This work was supported by ONR, directly and through NRL.

  13. Nanomaterials for biosensing with electrochemiluminescence (ECL) detection.

    PubMed

    Bertoncello, Paolo

    2011-01-01

    Analytical applications of nanomaterials used in electrochemiluminescence (ECL)-based detection methods are reviewed. Among nanomaterials, carbon-based nanomaterials (carbon nanotubes, graphene), metal nanoparticles, quantum dots, inorganic metal complexes and conducting polymers are considered. The most common mechanisms of ECL detections are also described in this review. Finally, challenges and perspectives of the use of such materials in chemical analysis are discussed.

  14. Conductive nanomaterials for printed electronics.

    PubMed

    Kamyshny, Alexander; Magdassi, Shlomo

    2014-09-10

    This is a review on recent developments in the field of conductive nanomaterials and their application in printed electronics, with particular emphasis on inkjet printing of ink formulations based on metal nanoparticles, carbon nanotubes, and graphene sheets. The review describes the basic properties of conductive nanomaterials suitable for printed electronics (metal nanoparticles, carbon nanotubes, and graphene), their stabilization in dispersions, formulations of conductive inks, and obtaining conductive patterns by using various sintering methods. Applications of conductive nanomaterials for electronic devices (transparent electrodes, metallization of solar cells, RFID antennas, TFTs, and light emitting devices) are also briefly reviewed.

  15. Spectroscopic Studies of Abiotic and Biological Nanomaterials: Silver Nanoparticles, Rhodamine 6G Adsorbed on Graphene, and c-Type Cytochromes and Type IV Pili in Geobacter sulfurreducens

    NASA Astrophysics Data System (ADS)

    Thrall, Elizabeth S.

    This thesis describes spectroscopic studies of three different systems: silver nanoparticles, the dye molecule rhodamine 6G adsorbed on graphene, and the type IV pili and c-type cytochromes produced by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens. Although these systems are quite different in some ways, they can all be considered examples of nanomaterials. A nanomaterial is generally defined as having at least one dimension below 100 nm in size. Silver nanoparticles, with sub-100 nm size in all dimensions, are examples of zero-dimensional nanomaterials. Graphene, a single atomic layer of carbon atoms, is the paradigmatic two-dimensional nanomaterial. And although bacterial cells are on the order of 1 μm in size, the type IV pili and multiheme c-type cytochromes produced by G. sulfurreducens can be considered to be one- and zero-dimensional nanomaterials respectively. A further connection between these systems is their strong interaction with visible light, allowing us to study them using similar spectroscopic tools. The first chapter of this thesis describes research on the plasmon-mediated photochemistry of silver nanoparticles. Silver nanoparticles support coherent electron oscillations, known as localized surface plasmons, at resonance frequencies that depend on the particle size and shape and the local dielectric environment. Nanoparticle absorption and scattering cross-sections are maximized at surface plasmon resonance frequencies, and the electromagnetic field is amplified near the particle surface. Plasmonic effects can enhance the photochemistry of silver particles alone or in conjunction with semiconductors according to several mechanisms. We study the photooxidation of citrate by silver nanoparticles in a photoelectrochemical cell, focusing on the wavelength-dependence of the reaction rate and the role of the semiconductor substrate. We find that the citrate

  16. Quasi-one-dimensional electronic states induced by an extended line defect in graphene: an analytic solution.

    PubMed

    Lü, Xiaoling; Jiang, Liwei; Zheng, Yisong

    2014-01-22

    Analytic solutions of the quasi-one-dimensional (q1D) electron states around an extended line defect in a graphene lattice are derived within the tight-binding model. Then, the electronic properties of this kind of boundary state in graphene are studied in detail. It is found that one subband composed of the even-parity boundary states emerges in the vicinity of the Dirac point. In particular, when the bulk band is gapped, such a one-dimensional subband remains in the bandgap, spanning two inequivalent valleys. In addition, this boundary state subband exhibits nontrivial dispersion, which can carry the valley polarized charge current flowing along the extended line defect. As a result, the line defect behaves like a one-dimensional channel for electronic transport. Moreover, its appearance in graphene or a hexagonal boron nitride sheet provides a promising way to print electric circuits in these two-dimensional materials.

  17. Screening-engineered Field-effect Photovoltaics and Synthesis, Characterization, and Applications of Carbon-based and Related Nanomaterials

    NASA Astrophysics Data System (ADS)

    Regan, William Raymond

    Carbon nanomaterials, and especially graphene (a 2D carbon allotrope), possess unique electronic, optical, and mechanical properties and allow access to both new physical phenomena and reinventions of familiar technologies. In the first part of this thesis (chapter 2), the low carrier density and high conductivity of graphene are used to repurpose the electric field effect (used for many decades in transistors) into a universally-applicable doping method for electrically-contacted semiconductors. This method, referred to as "screening-engineered field-effect photovoltaics" as the electric field doping is enabled by a carefully-designed poorly-screening electrode (e.g. graphene), is shown to open up many new low-cost and abundant semiconductors for use in high efficiency solar cells. We extend this method beyond ultrathin materials such as graphene and show that 1D nanowire electrodes made of any material also allow penetration of applied electric fields. The next part of this thesis (chapter 3) focuses on the fundamental properties of graphene -- its structure, synthesis, characterization, and manipulation -- and on using graphene as a building block for other nanostructures: grafold, graphene sandwiches and veils, and graphritos. In chapter 4, various graphene electronics are constructed and tested. Graphene field-effect transistors (FETs) and p-n junctions are fabricated to study the influence of the substrate on graphene carrier mobility and doping. Graphene nanoribbons and grafold FETs are made to investigate the effects of additional confinement on electronic transport. Chapter 5 summarizes synthesis methods and additional experiments with other nanomaterials, including dichalcogenides and chalcogenides (magnesium diboride, gallium selenide, and tin sulfide), carbon nanomaterials (carbon nanotubes and graphene), and copper oxide. Additional measurement and fabrication methods are discussed in appendix A.

  18. Interactions between Carbon Nanomaterials and Biomolecules.

    PubMed

    Han, Xu; Li, Shanghao; Peng, Zhili; Al-Yuobi, Abdulrahman Obaid; Omar Bashammakh, Abdulaziz Saleh; El-Shahawi, M S; Leblanc, Roger M

    2016-01-01

    Interactions between carbon nanomaterials, including carbon dots, fullerene, carbon nanotube, graphene, and graphene oxide, and biomolecules play an important role in the field of nanobiotechnology. Due to the unique properties of carbon nanomaterials and the magnificent features of their colloids, it shows high potential in fibrillation inhibition, high sensitivity sensor fabrication, bioimaging, drug delivery, and other areas. Hereby, we will go over different families of carbon nanomaterials regarding to the interaction between carbon nanomaterials and biomolecules at the interface, and their applications will be reviewed as well.

  19. Controlled Folding of Single Crystal Graphene.

    PubMed

    Wang, Bin; Huang, Ming; Kim, Na Yeon; Cunning, Benjamin V; Huang, Yuan; Qu, Deshun; Chen, Xianjue; Jin, Sunghwan; Biswal, Mandakini; Zhang, Xu; Lee, Sun Hwa; Lim, Hyunseob; Yoo, Won Jong; Lee, Zonghoon; Ruoff, Rodney S

    2017-03-08

    Folded graphene in which two layers are stacked with a twist angle between them has been predicted to exhibit unique electronic, thermal, and magnetic properties. We report the folding of a single crystal monolayer graphene film grown on a Cu(111) substrate by using a tailored substrate having a hydrophobic region and a hydrophilic region. Controlled film delamination from the hydrophilic region was used to prepare macroscopic folded graphene with good uniformity on the millimeter scale. This process was used to create many folded sheets each with a defined twist angle between the two sheets. By identifying the original lattice orientation of the monolayer graphene on Cu foil, or establishing the relation between the fold angle and twist angle, this folding technique allows for the preparation of twisted bilayer graphene films with defined stacking orientations and may also be extended to create folded structures of other two-dimensional nanomaterials.

  20. Purifying Nanomaterials

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor); Hurst, Janet (Inventor)

    2014-01-01

    A method of purifying a nanomaterial and the resultant purified nanomaterial in which a salt, such as ferric chloride, at or near its liquid phase temperature, is used to penetrate and wet the internal surfaces of a nanomaterial to dissolve impurities that may be present, for example, from processes used in the manufacture of the nanomaterial.

  1. Hybrid graphene-BC2N monolayers and nanoribbons with extended line defects: An ab initio study

    NASA Astrophysics Data System (ADS)

    Guerra, T.; Azevedo, S.; Machado, M.

    2017-02-01

    Opening a bandgap in graphene is probably one of the most important and urgent topics in the graphene research currently, since most of the proposed applications for graphene in nanoelectronic devices require the ability to adjust its bandgap. In this work we perform first-principles calculations to investigate the alterations at the structural, energetic, electronic and magnetic properties of hybrid graphene-BC2N monolayers (GBMLs) and zigzag graphene-BC2N nanoribbons (ZGBNRs) with different types of extended line defects (ELDs) at the grain boundary. Different reconstruction processes are observed forming different types of ELDs depending on the nature of the atoms into the grain boundary as well as the structures type, arrangement, position/size of domains, and inserted atoms. The inclusion of these ELDs creates edge type effects in the ELD at GBNMLs, inducing spin polarization and localization of states at the Fermi level. GBNMLs show a wide range of electronic structures going from semimetallic to semiconducting and metallic, which can have magnetic ground states with ferromagnetic and antiferromagnetic. ZGBNRs are always metallic with ferromagnetic coupling between carbon atoms at the structures edges.

  2. Is graphene a promising nano-material for promoting surface modification of implants or scaffold materials in bone tissue engineering?

    PubMed

    Gu, Ming; Liu, Yunsong; Chen, Tong; Du, Feng; Zhao, Xianghui; Xiong, Chunyang; Zhou, Yongsheng

    2014-10-01

    Bone tissue engineering promises to restore bone defects that are caused by severe trauma, congenital malformations, tumors, and nonunion fractures. How to effectively promote the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) or seed cells has become a hot topic in this field. Many researchers are studying the ways of conferring a pro-osteodifferentiation or osteoinductive capability on implants or scaffold materials, where osteogenesis of seed cells is promoted. Graphene (G) provides a new kind of coating material that may confer the pro-osteodifferentiation capability on implants and scaffold materials by surface modification. Here, we review recent studies on the effects of graphene on surface modifications of implants or scaffold materials. The ability of graphene to improve the mechanical and biological properties of implants or scaffold materials, such as nitinol and carbon nanotubes, and its ability to promote the adhesion, proliferation, and osteogenic differentiation of MSCs or osteoblasts have been demonstrated in several studies. Most previous studies were performed in vitro, but further studies will explore the mechanisms of graphene's effects on bone regeneration, its in vivo biocompatibility, its ability to promote osteodifferentiation, and its potential applications in bone tissue engineering.

  3. Is Graphene a Promising Nano-Material for Promoting Surface Modification of Implants or Scaffold Materials in Bone Tissue Engineering?

    PubMed Central

    Gu, Ming; Liu, Yunsong; Chen, Tong; Du, Feng; Zhao, Xianghui; Xiong, Chunyang

    2014-01-01

    Bone tissue engineering promises to restore bone defects that are caused by severe trauma, congenital malformations, tumors, and nonunion fractures. How to effectively promote the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) or seed cells has become a hot topic in this field. Many researchers are studying the ways of conferring a pro-osteodifferentiation or osteoinductive capability on implants or scaffold materials, where osteogenesis of seed cells is promoted. Graphene (G) provides a new kind of coating material that may confer the pro-osteodifferentiation capability on implants and scaffold materials by surface modification. Here, we review recent studies on the effects of graphene on surface modifications of implants or scaffold materials. The ability of graphene to improve the mechanical and biological properties of implants or scaffold materials, such as nitinol and carbon nanotubes, and its ability to promote the adhesion, proliferation, and osteogenic differentiation of MSCs or osteoblasts have been demonstrated in several studies. Most previous studies were performed in vitro, but further studies will explore the mechanisms of graphene's effects on bone regeneration, its in vivo biocompatibility, its ability to promote osteodifferentiation, and its potential applications in bone tissue engineering. PMID:24447041

  4. Anti-bacterial activity of graphene oxide as a new weapon nanomaterial to combat multidrug-resistance bacteria.

    PubMed

    Yousefi, Mohammadreza; Dadashpour, Mehdi; Hejazi, Maryam; Hasanzadeh, Mohammad; Behnam, Behzad; de la Guardia, Miguel; Shadjou, Nasrin; Mokhtarzadeh, Ahad

    2017-05-01

    Antibiotic resistance in microbial pathogens has become a serious health problem in the world. The increasing spread of hospital acquired infections especially in immunocompromised and cancer patients caused by multidrug-resistant (MDR) microbial pathogens is restricting the choices for impressive antibiotic therapy. So many efforts have been made to develop new compounds with antimicrobial activity. In recent years, nanoparticles, particularly graphene oxide (GO) nanoparticles have found many applications in various fields, including antibacterial action, pathogens bio detection, cancer therapy, and drug and gene delivery. The use of graphene oxide as an antibacterial agent for the treatment of infections with multidrug resistance is growing due to the unique physicochemical properties as wide surface area, excellent electrical and thermal conductivity, and biocompatibility. To reduce toxicity and increase the efficiency of graphene oxide as an antimicrobial agent, different surface modification and functionalization with inorganic nanostructures, biomolecules and polymers were developed. In this review article, we give our overview of the progress made on the graphene oxide nanocomposites as a new generation of antimicrobial agents.

  5. Evaluation of pulmonary and systemic toxicity following lung exposure to graphite nanoplates: a member of the graphene-based nanomaterial family.

    PubMed

    Roberts, Jenny R; Mercer, Robert R; Stefaniak, Aleksandr B; Seehra, Mohindar S; Geddam, Usha K; Chaudhuri, Ishrat S; Kyrlidis, Angelos; Kodali, Vamsi K; Sager, Tina; Kenyon, Allison; Bilgesu, Suzan A; Eye, Tracy; Scabilloni, James F; Leonard, Stephen S; Fix, Natalie R; Schwegler-Berry, Diane; Farris, Breanne Y; Wolfarth, Michael G; Porter, Dale W; Castranova, Vincent; Erdely, Aaron

    2016-06-21

    Graphene, a monolayer of carbon, is an engineered nanomaterial (ENM) with physical and chemical properties that may offer application advantages over other carbonaceous ENMs, such as carbon nanotubes (CNT). The goal of this study was to comparatively assess pulmonary and systemic toxicity of graphite nanoplates, a member of the graphene-based nanomaterial family, with respect to nanoplate size. Three sizes of graphite nanoplates [20 μm lateral (Gr20), 5 μm lateral (Gr5), and <2 μm lateral (Gr1)] ranging from 8-25 nm in thickness were characterized for difference in surface area, structure,, zeta potential, and agglomeration in dispersion medium, the vehicle for in vivo studies. Mice were exposed by pharyngeal aspiration to these 3 sizes of graphite nanoplates at doses of 4 or 40 μg/mouse, or to carbon black (CB) as a carbonaceous control material. At 4 h, 1 day, 7 days, 1 month, and 2 months post-exposure, bronchoalveolar lavage was performed to collect fluid and cells for analysis of lung injury and inflammation. Particle clearance, histopathology and gene expression in lung tissue were evaluated. In addition, protein levels and gene expression were measured in blood, heart, aorta and liver to assess systemic responses. All Gr samples were found to be similarly composed of two graphite structures and agglomerated to varying degrees in DM in proportion to the lateral dimension. Surface area for Gr1 was approximately 7-fold greater than Gr5 and Gr20, but was less reactive reactive per m(2). At the low dose, none of the Gr materials induced toxicity. At the high dose, Gr20 and Gr5 exposure increased indices of lung inflammation and injury in lavage fluid and tissue gene expression to a greater degree and duration than Gr1 and CB. Gr5 and Gr20 showed no or minimal lung epithelial hypertrophy and hyperplasia, and no development of fibrosis by 2 months post-exposure. In addition, the aorta and liver inflammatory and acute phase genes were transiently

  6. Soft bioelectronics using nanomaterials

    NASA Astrophysics Data System (ADS)

    Lee, Hyunjae; Kim, Dae-Hyeong

    2016-09-01

    Recently, soft bioelectronics has attracted significant attention because of its potential applications in biointegrated healthcare devices and minimally invasive surgical tools. Mechanical mismatch between conventional electronic/optoelectronic devices and soft human tissues/organs, however, causes many challenges in materials and device designs of bio-integrated devices. Intrinsically soft hybrid materials comprising twodimensional nanomaterials are utilized to solve these issues. In this paper, we describe soft bioelectronic devices based on graphene synthesized by a chemical vapor deposition process. These devices have unique advantages over rigid electronics, particularly in biomedical applications. The functionalized graphene is hybridized with other nanomaterials and fabricated into high-performance sensors and actuators toward wearable and minimally invasive healthcare devices. Integrated bioelectronic systems constructed using these devices solve pending issues in clinical medicine while providing new opportunities in personalized healthcare.

  7. Adsorption of toxic carbamate pesticide oxamyl from liquid phase by newly synthesized and characterized graphene quantum dots nanomaterials.

    PubMed

    Agarwal, Shilpi; Sadeghi, Nima; Tyagi, Inderjeet; Gupta, Vinod Kumar; Fakhri, Ali

    2016-09-15

    Graphene quantum dots have been synthesized using the microwave-assisted hydrothermal route. The surface textural and morphological structure of synthesized adsorbent i.e. graphene quantum dots was analyzed using various analytical techniques such as X-ray diffraction, Transmission electron Microscopy, Atomic Force Microscopy and N2 adsorption-desorption instrumental techniques. The application of graphene quantum dots as an adsorbent for the removal of noxious pesticide compound i.e. oxamyl from aqueous solutions was well investigated and elucidated. The impact of several effective parameters such as effect of agitation speed, pH, adsorbent dose, contact time, temperature and initial concentration on sorption efficiency was studied and optimized using batch adsorption experiments. The optimized pH for maximum oxamyl adsorption was found to be 8.0 and for the maximum adsorption rates the adsorbent dose of 0.6g was found to be optimum to carry out the adsorption with in less than 25min of contact time. From the results obtained, it is clear that for all contact times, an increase in oxamyl concentration resulted in increase in the percent oxamyl removal. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with the Langmuir isotherm and pseudo-second-order kinetic model.

  8. Carbon Nanomaterials as Antibacterial Colloids

    PubMed Central

    Maas, Michael

    2016-01-01

    Carbon nanomaterials like graphene, carbon nanotubes, fullerenes and the various forms of diamond have attracted great attention for their vast potential regarding applications in electrical engineering and as biomaterials. The study of the antibacterial properties of carbon nanomaterials provides fundamental information on the possible toxicity and environmental impact of these materials. Furthermore, as a result of the increasing prevalence of resistant bacteria strains, the development of novel antibacterial materials is of great importance. This article reviews current research efforts on characterizing the antibacterial activity of carbon nanomaterials from the perspective of colloid and interface science. Building on these fundamental findings, recent functionalization strategies for enhancing the antibacterial effect of carbon nanomaterials are described. The review concludes with a comprehensive outlook that summarizes the most important discoveries and trends regarding antibacterial carbon nanomaterials. PMID:28773737

  9. Electrochemical sensor for Isoniazid based on the glassy carbon electrode modified with reduced graphene oxide-Au nanomaterials.

    PubMed

    Guo, Zhuo; Wang, Ze-Yu; Wang, Hui-Hua; Huang, Guo-Qing; Li, Meng-Meng

    2015-12-01

    A sensitive electrochemical sensor has been fabricated to detect Isoniazid (INZ) using reduced graphene oxide (RGO) and Au nanocomposites (RGO-Au). RGO-Au nanocomposites were synthesized by a solution-based approach of chemical co-reduction of Au(III) and graphene oxide (GO), and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and Fourier transform infrared (FT-IR). The Au nanoparticles separate the RGO sheets in the precipitate and prevent RGO sheets from aggregation upon π-π stacking interactions. RGO-Au nanocomposites were used to modify the glassy carbon electrode (GCE). The electrochemical properties of RGO-Au/GCE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the RGO-Au/GCE exhibited remarkably strong electrocatalytic activities towards INZ. Under the optimized conditions, there was linear relationships between the peak currents and the concentrations in the range of 1.0×10(-7)M to 1.0×10(-3)M for INZ, with the limit of detection (LOD) (based on S/N=3) of 1.0×10(-8)M for INZ.

  10. Superconductivity in carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Dlugon, Katarzyna

    The purpose of this thesis is to explain the phenomenon of superconductivity in carbon nanomaterials such as graphene, fullerenes and carbon nanotubes. In the introductory chapter, there is a description of superconductivity and how it occurs at critical temperature (Tc) that is characteristic and different to every superconducting material. The discovery of superconductivity in mercury in 1911 by Dutch physicist Heike Kamerlingh Onnes is also mentioned. Different types of superconductors, type I and type II, low and high temperatures superconductors, as well as the BCS theory that was developed in 1957 by Bardeen, Cooper, and Schrieffer, are also described in detail. The BCS theory explains how Cooper's pairs are formed and how they are responsible for the superconducting properties of many materials. The following chapters explain superconductivity in doped fullerenes, graphene and carbon nanotubes, respectively. There is a thorough explanation followed by many examples of different types of carbon nanomaterials in which small changes in chemical structure cause significant changes in superconducting properties. The goal of this research was not only to take into consideration well known carbon based superconductors but also to search for the newest available materials such as the fullerene nanowhiskers discovered quite recently. There is also a presentation of fairly new ideas about inducing superconductivity in a monolayer of graphene which is more challenging than inducing superconductivity in graphite by simply intercalating metal atoms between its graphene sheets. An effort has been taken to look for any available information about carbon nanomaterials that have the potential to superconduct at room temperature, mainly because discovery of such materials would be a real revolution in the modern world, although no such materials have been discovered yet.

  11. Nanomaterials for optical data storage

    NASA Astrophysics Data System (ADS)

    Gu, Min; Zhang, Qiming; Lamon, Simone

    2016-12-01

    The growing amount of data that is generated every year creates an urgent need for new and improved data storage methods. Nanomaterials, which have unique mechanical, electronic and optical properties owing to the strong confinement of electrons, photons and phonons at the nanoscale, are enabling the development of disruptive methods for optical data storage with ultra-high capacity, ultra-long lifetime and ultra-low energy consumption. In this Review, we survey recent advancements in nanomaterials technology towards the next generation of optical data storage systems, focusing on metallic nanoparticles, graphene and graphene oxide, semiconductor quantum dots and rare-earth-doped nanocrystals. We conclude by discussing the use of nanomaterials in data storage systems that do not rely on optical mechanisms and by surveying the future prospects for the field.

  12. Planar graphene oxide-based magnetic ionic liquid nanomaterial for extraction of chlorophenols from environmental water samples coupled with liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Mei-Qiang; Su, Jie; Hu, Jian-Qiang; Wang, Qian; Dong, Chun-Ying; Pan, Sheng-Dong; Jin, Mi-Cong

    2016-08-12

    A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Role of solution chemistry in the retention and release of graphene oxide nanomaterials in uncoated and iron oxide-coated sand.

    PubMed

    Wang, Dengjun; Shen, Chongyang; Jin, Yan; Su, Chunming; Chu, Lingyang; Zhou, Dongmei

    2017-02-01

    Understanding the fate and transport including remobilization of graphene oxide nanomaterials (GONMs) in the subsurface would enable us to expedite their benign use and evaluate their environmental impacts and health risks. In this study, the retention and release of GONMs were investigated in water-saturated columns packed with uncoated sand (Un-S) or iron oxide-coated sand (FeS) at environmentally relevant solution chemistries (1-100mM KCl and 0.1-10mM CaCl2 at pH7 and 11). Our results showed that increasing ionic strength (IS) inhibited GONMs' transport, and the impact of K(+) was less than Ca(2+). The positively charged iron oxide coating on sand surfaces immobilized the negatively charged GONMs (pH7) in the primary minimum, yielding hyperexponential retention profiles particularly in Ca(2+). A stepwise decrease in pore-water IS caused detachment of previously retained GONMs. The mass of GONMs released during each detachment step correlated positively with the difference in secondary minimum depth (ΔΦmin2) at each IS, indicating that the released GONMs were retained in the secondary minimum. While most retained GONMs were re-entrained upon lowering pore-water IS in Un-S, decreasing IS only released limited GONMs in FeS, which were captured in the primary minimum. Introducing 1mM NaOH (pH11) released most retained GONMs in FeS; and average hydrodynamic diameters of the detached GONMs upon injecting NaOH were significantly smaller than those of GONMs in the influent and retentate, suggesting that NaOH induced GONMs disaggregation. Our findings advance current knowledge to better predict NMs' fate and transport under various solution chemistries such as during rainfall events or in the mixing zones between sea water and fresh water where transient IS changes drastically.

  14. New Insight into the Aggregation of Graphene Oxide Using Molecular Dynamics Simulations and Extended Derjaguin-Landau-Verwey-Overbeek Theory.

    PubMed

    Tang, Huan; Zhao, Ying; Yang, Xiaonan; Liu, Dongmei; Shao, Penghui; Zhu, Zhigao; Shan, Sujie; Cui, Fuyi; Xing, Baoshan

    2017-09-05

    A comparative experimental and molecular dynamics (MD) simulation study was carried out to investigate the aggregation of graphene oxide (GO). Mechanisms behind the effects of solution chemistries (pH, metal ions, and tannic acid (TA)) and GO topology (carboxyl content, GO size, and GO thickness) were uncovered. For example, MD results showed that more hydrogen bonds formed between GO and water at higher pH, according well with the increased hydrophilicity of GO calculated based on contact angle measurements. Radial distribution functions analysis suggested Ca(2+) interacted more strongly with GO than Na(+), which explained the experimental observations that Ca(2+) was more effective in accelerating the aggregation process than Na(+). The adsorption-bridging and steric effects of TA were simulated, and TA was found to be unfolded upon wrapping on GOs, leading to an increased capacity for ion and solvent binding. The evaluations of contributions to GO hydrophilicity, electrostatic energy, and intensities of interactions with metal ions indicated the carboxyl group is the essential functional group in mediating the stability of GO. Overall, by combining MD simulations with experimental measurements, we provided molecular-level understandings toward the aggregation of GO, indicating MD, if used properly, can be applied as a useful tool to obtain insights into the aggregation of nanomaterials.

  15. Ice Nucleation Properties of Oxidized Carbon Nanomaterials

    PubMed Central

    2015-01-01

    Heterogeneous ice nucleation is an important process in many fields, particularly atmospheric science, but is still poorly understood. All known inorganic ice nucleating particles are relatively large in size and tend to be hydrophilic. Hence it is not obvious that carbon nanomaterials should nucleate ice. However, in this paper we show that four different readily water-dispersible carbon nanomaterials are capable of nucleating ice. The tested materials were carboxylated graphene nanoflakes, graphene oxide, oxidized single walled carbon nanotubes and oxidized multiwalled carbon nanotubes. The carboxylated graphene nanoflakes have a diameter of ∼30 nm and are among the smallest entities observed so far to nucleate ice. Overall, carbon nanotubes were found to nucleate ice more efficiently than flat graphene species, and less oxidized materials nucleated ice more efficiently than more oxidized species. These well-defined carbon nanomaterials may pave the way to bridging the gap between experimental and computational studies of ice nucleation. PMID:26267196

  16. Ice Nucleation Properties of Oxidized Carbon Nanomaterials.

    PubMed

    Whale, Thomas F; Rosillo-Lopez, Martin; Murray, Benjamin J; Salzmann, Christoph G

    2015-08-06

    Heterogeneous ice nucleation is an important process in many fields, particularly atmospheric science, but is still poorly understood. All known inorganic ice nucleating particles are relatively large in size and tend to be hydrophilic. Hence it is not obvious that carbon nanomaterials should nucleate ice. However, in this paper we show that four different readily water-dispersible carbon nanomaterials are capable of nucleating ice. The tested materials were carboxylated graphene nanoflakes, graphene oxide, oxidized single walled carbon nanotubes and oxidized multiwalled carbon nanotubes. The carboxylated graphene nanoflakes have a diameter of ∼30 nm and are among the smallest entities observed so far to nucleate ice. Overall, carbon nanotubes were found to nucleate ice more efficiently than flat graphene species, and less oxidized materials nucleated ice more efficiently than more oxidized species. These well-defined carbon nanomaterials may pave the way to bridging the gap between experimental and computational studies of ice nucleation.

  17. Superhydrophobic functionalized graphene aerogels.

    PubMed

    Lin, Yirong; Ehlert, Gregory J; Bukowsky, Colton; Sodano, Henry A

    2011-07-01

    Carbon-based nanomaterials such as carbon nanotubes and graphene are excellent candidates for superhydrophobic surfaces because of their intrinsically high surface area and nonpolar carbon structure. This paper demonstrates that graphene aerogels with a silane surface modification can provide superhydrophobicity. Graphene aerogels of various concentrations were synthesized and the receding contact angle of a water droplet was measured. It is shown that graphene aerogels are hydrophobic and become superhydrophobic following the application of a fluorinated surfactant. The aerogels produced for this experiment outperform previous carbon nanomaterials in creating superhydrophobic surfaces and offer a more scalable synthetic procedure for production.

  18. Upconversion of rare Earth nanomaterials.

    PubMed

    Sun, Ling-Dong; Dong, Hao; Zhang, Pei-Zhi; Yan, Chun-Hua

    2015-04-01

    Rare earth nanomaterials, which feature long-lived intermediate energy levels and intraconfigurational 4f-4f transitions, are promising supporters for photon upconversion. Owing to their unique optical properties, rare earth upconversion nanomaterials have found applications in bioimaging, theranostics, photovoltaic devices, and photochemical reactions. Here, we review recent advances in the photon upconversion processes of these nanomaterials. We start by considering energy transfer models involved in the study of upconversion emissions, as well as well-established synthesis strategies to control the size and shape of rare earth upconversion nanomaterials. Progress in engineering energy transfer pathways, which play a dominant role in determining upconversion emission outputs, is then discussed. Lastly, representative optical applications of these materials are considered. The aim of this review is to provide inspiration for researchers to explore novel upconversion nanomaterials and extended optical applications.

  19. Bridging Redox Species-Coated Graphene Oxide Sheets to Electrode for Extending Battery Life Using Nanocomposite Electrolyte.

    PubMed

    Huang, Yi Fu; Ruan, Wen Hong; Lin, Dong Ling; Zhang, Ming Qiu

    2017-01-11

    Substituting conventional electrolyte for redox electrolyte has provided a new intriguing method for extending battery life. The efficiency of utilizing the contained redox species (RS) in the redox electrolyte can benefit from increasing the specific surface area of battery electrodes from the electrode side of the electrode-electrolyte interface, but is not limited to that. Herein, a new strategy using nanocomposite electrolyte is proposed to enlarge the interface with the aid of nanoinclusions from the electrolyte side. To do this, graphene oxide (GO) sheets are first dispersed in the electrolyte solution of tungstosilicic salt/lithium sulfate/poly(vinyl alcohol) (SiWLi/Li2SO4/PVA), and then the sheets are bridged to electrode, after casting and evaporating the solution on the electrode surface. By applying in situ conductive atomic force microscopy and Raman spectra, it is confirmed that the GO sheets doped with RS of SiWLi/Li2SO4 can be bridged and electrically reduced as an extended electrode-electrolyte interface. As a result, the RS-coated GO sheets bridged to LiTi2(PO4)3//LiMn2O4 battery electrodes are found to deliver extra energy capacity (∼30 mAh/g) with excellent electrochemical cycling stability, which successfully extends the battery life by over 50%.

  20. Roles of Direct and Indirect Light-Induced Transformations of Carbon Nanomaterials in Exposures in Aquatic Systems

    EPA Science Inventory

    Carbon nanomaterials (CNMs) such as fullerenes, carbon nanotubes and graphene-based nanomaterials have a variety of useful characteristics such as extraordinary electron and heat conducting abilities, optical absorption and mechanical properties, and potential applications in tra...

  1. Roles of Direct and Indirect Light-Induced Transformations of Carbon Nanomaterials in Exposures in Aquatic Systems

    EPA Science Inventory

    Carbon nanomaterials (CNMs) such as fullerenes, carbon nanotubes and graphene-based nanomaterials have a variety of useful characteristics such as extraordinary electron and heat conducting abilities, optical absorption and mechanical properties, and potential applications in tra...

  2. Synthesizing and Characterizing Graphene via Raman Spectroscopy: An Upper-Level Undergraduate Experiment That Exposes Students to Raman Spectroscopy and a 2D Nanomaterial

    ERIC Educational Resources Information Center

    Parobek, David; Shenoy, Ganesh; Zhou, Feng; Peng, Zhenbo; Ward, Michelle; Liu, Haitao

    2016-01-01

    In this upper-level undergraduate experiment, students utilize micro-Raman spectroscopy to characterize graphene prepared by mechanical exfoliation and chemical vapor deposition (CVD). The mechanically exfoliated samples are prepared by the students while CVD graphene can be purchased or obtained through outside sources. Owing to the intense Raman…

  3. Synthesizing and Characterizing Graphene via Raman Spectroscopy: An Upper-Level Undergraduate Experiment That Exposes Students to Raman Spectroscopy and a 2D Nanomaterial

    ERIC Educational Resources Information Center

    Parobek, David; Shenoy, Ganesh; Zhou, Feng; Peng, Zhenbo; Ward, Michelle; Liu, Haitao

    2016-01-01

    In this upper-level undergraduate experiment, students utilize micro-Raman spectroscopy to characterize graphene prepared by mechanical exfoliation and chemical vapor deposition (CVD). The mechanically exfoliated samples are prepared by the students while CVD graphene can be purchased or obtained through outside sources. Owing to the intense Raman…

  4. Reproductive toxicity of carbon nanomaterials: a review

    NASA Astrophysics Data System (ADS)

    Vasyukova, I.; Gusev, A.; Tkachev, A.

    2015-11-01

    In the current review, we assembled the experimental evidences of an association between carbon nanomaterials including carbon black, graphite nanoplatelets, graphene, single- and multi-walled carbon nanotubes, and fullerene exposure and adverse reproductive and developmental effects, in vitro and in vivo studies. It is shown that carbon nanomaterials reveal toxic effect on reproductive system and offspring development of the animals of various system groups to a certain degree depending on carbon crystal structure. Although this paper provides initial information about the potential male and female reproductive toxicity of carbon nanomaterials, further studies, using characterized nanoparticles, relevant routes of administration, and doses closely reflecting all the expected levels of exposure are needed.

  5. Nanomaterial Based Sensors for NASA Missions

    NASA Technical Reports Server (NTRS)

    Koehne, Jessica E.

    2016-01-01

    Nanomaterials such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene and metal nanowires have shown interesting electronic properties and therefore have been pursued for a variety of space applications requiring ultrasensitive and light-weight sensor and electronic devices. We have been pursuing development of chemical and biosensors using carbon nanotubes and carbon nanofibers for the last several years and this talk will present the benefits of nanomaterials these applications. More recently, printing approaches to manufacturing these devices have been explored as a strategy that is compatible to a microgravity environment. Nanomaterials are either grown in house or purchased and processed as electrical inks. Chemical modification or coatings are added to the nanomaterials to tailor the nanomaterial to the exact application. The development of printed chemical sensors and biosensors will be discussed for applications ranging from crew life support to exploration missions.

  6. Auxetic nanomaterials: Recent progress and future development

    NASA Astrophysics Data System (ADS)

    Jiang, Jin-Wu; Kim, Sung Youb; Park, Harold S.

    2016-12-01

    Auxetic materials (materials with negative Poisson's ratio) and nanomaterials have independently been, for many years, two of the most active research fields in material science. Recently, these formerly independent fields have begun to intersect in new and interesting ways due to the recent discovery of auxeticity in nanomaterials like graphene, metal nanoplates, black phosphorus, and others. Here, we review the research emerging at the intersection of auxeticity and nanomaterials. We first survey the atomistic mechanisms, both intrinsic and extrinsic, that have been found, primarily through atomistic simulations, to cause auxeticity in nanomaterials. We then outline the available experimental evidence for auxetic nanomaterials. In order to lay the groundwork for future work in this exciting area, we close by discussing several future prospects as well as the current challenges in this field.

  7. Surface potentials and layer charge distributions in few-layer graphene films.

    PubMed

    Datta, Sujit S; Strachan, Douglas R; Mele, E J; Johnson, A T Charlie

    2009-01-01

    Graphene-derived nanomaterials are emerging as ideal candidates for postsilicon electronics. Elucidating the electronic interaction between an insulating substrate and few-layer graphene (FLG) films is crucial for device applications. Here, we report electrostatic force microscopy (EFM) measurements revealing that the FLG surface potential increases with film thickness, approaching a "bulk" value for samples with five or more graphene layers. This behavior is in sharp contrast with that expected for conventional conducting or semiconducting films, and derives from unique aspects of charge screening by graphene's relativistic low energy carriers. EFM measurements resolve previously unseen electronic perturbations extended along crystallographic directions of structurally disordered FLGs, likely resulting from long-range atomic defects. These results have important implications for graphene nanoelectronics and provide a powerful framework by which key properties can be further investigated.

  8. A real-space study of random extended defects in solids: Application to disordered Stone-Wales defects in graphene

    NASA Astrophysics Data System (ADS)

    Chowdhury, Suman; Baidya, Santu; Nafday, Dhani; Halder, Soumyajyoti; Kabir, Mukul; Sanyal, Biplab; Saha-Dasgupta, Tanusri; Jana, Debnarayan; Mookerjee, Abhijit

    2014-07-01

    We propose here a first-principles, parameter free, real space method for the study of disordered extended defects in solids. We shall illustrate the power of the technique with an application to graphene sheets with randomly placed Stone-Wales defects and shall examine the signature of such random defects on the density of states as a function of their concentration. The technique is general enough to be applied to a whole class of systems with lattice translational symmetry broken not only locally but by extended defects and defect clusters. The real space approach will allow us to distinguish signatures of specific defects and defect clusters. The authors go on to remark that although this disorder may not affect the vibrational spectrum significantly, the electronic structure obtained from a periodic array of SW defects needs to be interpreted with care. Our real space recursion approach [41] makes no appeal to lattice translational symmetry and is thus ideal for studying topological disorder and its effect on electronic structure. The illustration of this point is the justification of our proposed methodology and the main focus of this communication.

  9. Role of solution chemistry in the retention and release of graphene oxide nanomaterials in uncoated and iron oxide-coated sand

    EPA Science Inventory

    Upon increasing production and use of graphene oxide nanoparticles (GONPs), concerns agitate over their potential impacts and risks to the environment, ecosystem, and human health. An improved understanding of the fate and transport including remobilization of GONPs in the subsur...

  10. Role of solution chemistry in the retention and release of graphene oxide nanomaterials in uncoated and iron oxide-coated sand

    EPA Science Inventory

    Upon increasing production and use of graphene oxide nanoparticles (GONPs), concerns agitate over their potential impacts and risks to the environment, ecosystem, and human health. An improved understanding of the fate and transport including remobilization of GONPs in the subsur...

  11. Dimensionality of Carbon Nanomaterials Determines the Binding and Dynamics of Amyloidogenic Peptides: Multiscale Theoretical Simulations

    PubMed Central

    Hine, Nicholas D. M.; Mostofi, Arash A.; Yarovsky, Irene

    2013-01-01

    Experimental studies have demonstrated that nanoparticles can affect the rate of protein self-assembly, possibly interfering with the development of protein misfolding diseases such as Alzheimer's, Parkinson's and prion disease caused by aggregation and fibril formation of amyloid-prone proteins. We employ classical molecular dynamics simulations and large-scale density functional theory calculations to investigate the effects of nanomaterials on the structure, dynamics and binding of an amyloidogenic peptide apoC-II(60-70). We show that the binding affinity of this peptide to carbonaceous nanomaterials such as C60, nanotubes and graphene decreases with increasing nanoparticle curvature. Strong binding is facilitated by the large contact area available for π-stacking between the aromatic residues of the peptide and the extended surfaces of graphene and the nanotube. The highly curved fullerene surface exhibits reduced efficiency for π-stacking but promotes increased peptide dynamics. We postulate that the increase in conformational dynamics of the amyloid peptide can be unfavorable for the formation of fibril competent structures. In contrast, extended fibril forming peptide conformations are promoted by the nanotube and graphene surfaces which can provide a template for fibril-growth. PMID:24339760

  12. Toxicological properties of nanomaterials.

    PubMed

    Zhang, Mingyi; Jin, Junjiang; Chang, Ya-Nan; Chang, Xueling; Xing, Gengmei

    2014-01-01

    The development of engineered nanomaterials opens tremendous opportunities for their application as therapeutic and diagnostic tools, as well as in the fields of consumer products. As the newly developed material subtype, they exhibit great activities for the high ratio of surface to total atoms. In the bio-system, the activity can render nanomaterials some negative outcomes for their unexpected deposition in organs and cells, the cellular response to the exogenous substance and the interfacial reaction with biomolecules. In this review, we have discussed the evolution of nanotoxicology studies in the past ten years mainly emerging from our laboratory. The early in vivo studies mainly focused on the biokinetic of inhaled nanoparticles and their impacts on mammal tissues, such as the central nervous system, respiratory system, cardiovascular system and so on. Then the scope extended to engineered nanomaterials used as food additives and medicines, as well as their influence on alimentary and reproductive systems. In vitro experiments to study the nanoparticle-cell interaction and nanoparticle-biomolecule interplay are indispensable to reveal the mechanisms behind the macroscopic phenomenon. In addition, novel tools such as new model organisms and synchrotron radiation-based techniques are used to facilitate our understanding of the toxicology profile of nanomaterials.

  13. Measuring graphene adhesion using atomic force microscopy with a microsphere tip

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Zhu, Yong

    2015-06-01

    Van der Waals adhesion between graphene and various substrates has an important impact on the physical properties, device applications and nanomanufacturing processes of graphene. Here we report a general, high-throughput and reliable method that can measure adhesion energies between ultraflat graphene and a broad range of materials using atomic force microscopy with a microsphere tip. In our experiments, only van der Waals force between the tip and a graphene flake is measured. The Maugis-Dugdale theory is employed to convert the measured adhesion force using AFM to the adhesion energy. The ultraflatness of monolayer graphene on mica eliminates the effect of graphene surface roughness on the adhesion, while roughness of the microsphere tip is addressed by the modified Rumpf model. Adhesion energies of monolayer graphene to SiO2 and Cu are obtained as 0.46 and 0.75 J m-2, respectively. This work provides valuable insight into the mechanism of graphene adhesion and can readily extend to the adhesion measurement for other 2D nanomaterials.Van der Waals adhesion between graphene and various substrates has an important impact on the physical properties, device applications and nanomanufacturing processes of graphene. Here we report a general, high-throughput and reliable method that can measure adhesion energies between ultraflat graphene and a broad range of materials using atomic force microscopy with a microsphere tip. In our experiments, only van der Waals force between the tip and a graphene flake is measured. The Maugis-Dugdale theory is employed to convert the measured adhesion force using AFM to the adhesion energy. The ultraflatness of monolayer graphene on mica eliminates the effect of graphene surface roughness on the adhesion, while roughness of the microsphere tip is addressed by the modified Rumpf model. Adhesion energies of monolayer graphene to SiO2 and Cu are obtained as 0.46 and 0.75 J m-2, respectively. This work provides valuable insight into the

  14. Graphene and Graphene Oxide: Biofunctionalization and Applications in Biotechnology

    SciTech Connect

    Wang, Ying; Li, Zhaohui; Wang, Jun; Li, Jinghong; Lin, Yuehe

    2011-05-01

    Graphene is the basic building block of zero-dimensional fullerene, 1D carbon nanotubes, and 3D graphite. Graphene has a unique planar structure as well as novel electronic properties, which have attracted great interest from scientists. This review selectively analyzes current advances in the field of graphene bioapplications. In particular, the functionalization of graphene for biological applications, FRET-based biosensor development by using graphene-based nanomaterials, and the investigation of graphene for living cell studies have been summarized in more details. Future perspectives and possible challenges in this rapidly developing area are also discussed.

  15. Carbon Nanomaterials in Biological Studies and Biomedicine.

    PubMed

    Teradal, Nagappa L; Jelinek, Raz

    2017-09-01

    The "carbon nano-world" has made over the past few decades huge contributions in diverse scientific disciplines and technological advances. While dramatic advances have been widely publicized in using carbon nanomaterials such as fullerenes, carbon nanotubes, and graphene in materials sciences, nano-electronics, and photonics, their contributions to biology and biomedicine have been noteworthy as well. This Review focuses on the use of carbon nanotubes (CNTs), graphene, and carbon quantum dots [encompassing graphene quantum dots (GQDs) and carbon dots (C-dots)] in biologically oriented materials and applications. Examples of these remarkable nanomaterials in bio-sensing, cell- and tissue-imaging, regenerative medicine, and other applications are presented and discussed, emphasizing the significance of their unique properties and their future potential. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Recent applications of nanomaterials in capillary electrophoresis.

    PubMed

    González-Curbelo, Miguel Ángel; Varela-Martínez, Diana Angélica; Socas-Rodríguez, Bárbara; Hernández-Borges, Javier

    2017-10-01

    Nanomaterials have found an important place in Analytical Chemistry and, in particular, in Separation Science. Among them, metal-organic frameworks, magnetic and non-magnetic nanoparticles, carbon nanotubes and graphene, as well as their combinations, are the most important nanomaterials that have been used up to now. Concerning capillary electromigration techniques, these nanomaterials have also been used as both pseudostationary phases in electrokinetic chromatography (EKC) and as stationary phases in microchip capillary electrophoresis (CE) and capillary electrochromatography (CEC), as a result of their interesting and particular properties. This review article pretends to provide a general and critical revision of the most recent applications of nanomaterials in this field (period 2010-2017). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Graphene Sandwiched Mesostructured Li-Ion Battery Electrodes.

    PubMed

    Liu, Jinyun; Zheng, Qiye; Goodman, Matthew D; Zhu, Haoyue; Kim, Jinwoo; Krueger, Neil A; Ning, Hailong; Huang, Xingjiu; Liu, Jinhuai; Terrones, Mauricio; Braun, Paul V

    2016-09-01

    A deterministic graphene-sandwiched Li-ion battery electrode consisting of an integrated 3D mesostructure of electrochemically active materials and graphene is presented. As demonstrations, electrodes with active nanomaterials that coat (V2 O5 @graphene@V2 O5 cathode) or are coated by (graphene@Si@graphene anode) graphene are fabricated. These electrodes exhibit high capacities and ultralong cycle lives (the cathode can be cycled over 2000 times with minimal capacity fade).

  18. Combustion-Assisted Photonic Annealing of Printable Graphene Inks via Exothermic Binders.

    PubMed

    Secor, Ethan B; Gao, Theodore Z; Dos Santos, Manuel H; Wallace, Shay G; Putz, Karl W; Hersam, Mark C

    2017-09-06

    High-throughput and low-temperature processing of high-performance nanomaterial inks is an important technical challenge for large-area, flexible printed electronics. In this report, we demonstrate nitrocellulose as an exothermic binder for photonic annealing of conductive graphene inks, leveraging the rapid decomposition kinetics and built-in energy of nitrocellulose to enable versatile process integration. This strategy results in superlative electrical properties that are comparable to extended thermal annealing at 350 °C, using a pulsed light process that is compatible with thermally sensitive substrates. The resulting porous microstructure and broad liquid-phase patterning compatibility are exploited for printed graphene microsupercapacitors on paper-based substrates.

  19. Application of Carbon Nanomaterials in Lithium-Ion Battery Electrodes

    NASA Astrophysics Data System (ADS)

    Jaber-Ansari, Laila

    Carbon nanomaterials such as single-walled carbon nanotubes (SWCNTs) and graphene have emerged as leading additives for high capacity nanocomposite lithium ion battery electrodes due to their ability to improve electrode conductivity, current collection efficiency, and charge/discharge rate for high power applications. In this work, the these nanomaterials have been developed and their properties have been fine-tuned to help solve fundamental issues in conventional lithium ion battery electrodes. Towards this end, the application of SWCNTs in lithium-ion anodes has been studied. As-grown SWCNTs possess a distribution of physical and electronic structures, and it is of high interest to determine which subpopulations of SWCNTs possess the highest lithiation capacity and to develop processing methods that can enhance the lithiation capacity of underperforming SWCNT species. Towards this end, SWCNT electronic type purity is controlled via density gradient ultracentrifugation, enabling a systematic study of the lithiation of SWCNTs as a function of metal versus semiconducting content. Experimentally, vacuum filtered freestanding films of metallic SWCNTs are found to accommodate lithium with an order of magnitude higher capacity than their semiconducting counterparts. In contrast, SWCNT film densification leads to the enhancement of the lithiation capacity of semiconducting SWCNTs to levels comparable to metallic SWCNTs, which is corroborated by theoretical calculations. To understand the interaction of the graphene with lithium ions and electrolyte species during electrochemical we use Raman spectroscopy in a model system of monolayer graphene transferred on a Si(111) substrate and density functional theory (DFT) to investigate defect formation as a function of lithiation. This model system enables the early stages of defect formation to be probed in a manner previously not possible with commonly-used reduced graphene oxide or multilayer graphene substrates. Using ex

  20. Emerging Carbon and Post-Carbon Nanomaterial Inks for Printed Electronics.

    PubMed

    Secor, Ethan B; Hersam, Mark C

    2015-02-19

    Carbon and post-carbon nanomaterials present desirable electrical, optical, chemical, and mechanical attributes for printed electronics, offering low-cost, large-area functionality on flexible substrates. In this Perspective, recent developments in carbon nanomaterial inks are highlighted. Monodisperse semiconducting single-walled carbon nanotubes compatible with inkjet and aerosol jet printing are ideal channels for thin-film transistors, while inkjet, gravure, and screen-printable graphene-based inks are better-suited for electrodes and interconnects. Despite the high performance achieved in prototype devices, additional effort is required to address materials integration issues encountered in more complex systems. In this regard, post-carbon nanomaterial inks (e.g., electrically insulating boron nitride and optically active transition-metal dichalcogenides) present promising opportunities. Finally, emerging work to extend these nanomaterial inks to three-dimensional printing provides a path toward nonplanar devices. Overall, the superlative properties of these materials, coupled with versatile assembly by printing techniques, offer a powerful platform for next-generation printed electronics.

  1. Heat-Initiated Chemical Functionalization of Graphene

    PubMed Central

    Gao, Guodong; Liu, Dandan; Tang, Shangcheng; Huang, Can; He, Mengci; Guo, Yu; Sun, Xiudong; Gao, Bo

    2016-01-01

    A heat-initiated chemical reaction was developed to functionalize CVD-grown graphene at wafer scale and the reaction was universally extended to carbon nanotubes, and other precursors that could be thermally converted to active radicals. The chemical reaction can occur in absence of oxygen and water vapor when the temperature is above the decomposition temperature of the reactants. The chemical reaction was also found to be substrate-dependent due to surface doping and inhomogeneity. A large-scale graphene pattern was demonstrated by combing with microfluidic technique. This heat-initiated solid-phase chemical reaction provides a facile and environmentally friendly approach to functionalize carbon nanomaterials with various functional groups. PMID:26818231

  2. 2D nanomaterials based electrochemical biosensors for cancer diagnosis.

    PubMed

    Wang, Lu; Xiong, Qirong; Xiao, Fei; Duan, Hongwei

    2017-03-15

    Cancer is a leading cause of death in the world. Increasing evidence has demonstrated that early diagnosis holds the key towards effective treatment outcome. Cancer biomarkers are extensively used in oncology for cancer diagnosis and prognosis. Electrochemical sensors play key roles in current laboratory and clinical analysis of diverse chemical and biological targets. Recent development of functional nanomaterials offers new possibilities of improving the performance of electrochemical sensors. In particular, 2D nanomaterials have stimulated intense research due to their unique array of structural and chemical properties. The 2D materials of interest cover broadly across graphene, graphene derivatives (i.e., graphene oxide and reduced graphene oxide), and graphene-like nanomaterials (i.e., 2D layered transition metal dichalcogenides, graphite carbon nitride and boron nitride nanomaterials). In this review, we summarize recent advances in the synthesis of 2D nanomaterials and their applications in electrochemical biosensing of cancer biomarkers (nucleic acids, proteins and some small molecules), and present a personal perspective on the future direction of this area.

  3. Layered-nanomaterial-amplified chemiluminescence systems and their analytical applications.

    PubMed

    Zhong, Jinpan; Yuan, Zhiqin; Lu, Chao

    2016-12-01

    Layered nanomaterial has become a popular hierarchical material for amplifying chemiluminescence (CL) in recent years, mainly because of its ease of preparation and modification, large specific surface area, and high catalytic activity. In this review, we mainly discuss layered-nanomaterial-amplified CL systems based on graphene and its derivatives, layered double hydroxides, and clay. Detection mechanisms and strategies of layered-nanomaterial-amplified CL systems are provided to show the basic concepts for designing sensitive and selective sensing systems. Strategies for expanding the applications of layered-nanomaterial-amplified CL systems by combination with surfactants, quantum dots, organic dyes, and nanoparticles are introduced for the analysis of various analytes in real samples. The challenges and future trends of layered-nanomaterial-amplified CL systems are discussed at the end of the review. Graphical Abstract Schematic illustration of layered nanomaterial amplified chemiluminescence.

  4. Genotoxicity of Graphene in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Sharma, Ananya

    Rapid advances in nanotechnology necessitate assessment of the safety of nanomaterials in the resulting products and applications. One key nanomaterial attracting much interest in many areas of science and technology is graphene. Graphene is a one atom thick carbon allotrope arranged in a two-dimensional honeycomb lattice. In addition to being extremely thin, graphene has several extraordinary physical properties such as its exceptional mechanical strength, thermal stability, and high electrical conductivity. Graphene itself is relatively chemically inert and therefore pristine graphene must undergo a process called functionalization, which is combination of chemical and physical treatments that change the properties of graphene, to make it chemically active. Functionalization of graphene is of crucial importance as the end application of graphene depends on proper functionalization. In the field of medicine, graphene is currently a nanomaterial of high interest for building biosensors, DNA transistors, and probes for cancer detection. Despite the promising applications of graphene in several areas of biomedicine, there have been only few studies in recent years that focus on evaluating cytotoxicity of graphene on cells, and almost no studies that investigate how graphene exposure affects cellular genetic material. Therefore, in this study we used a novel approach to evaluate the genotoxicity, i.e., the effects of graphene on DNA, using Escherichia coli as a prokaryotic model organism.

  5. Capillarity Composited Recycled Paper/Graphene Scaffold for Lithium-Sulfur Batteries with Enhanced Capacity and Extended Lifespan.

    PubMed

    Zhang, Yunya; Gao, Zan; Li, Xiaodong

    2017-09-20

    An effective strategy to tackle the twin crises of global deforestation and fossil fuel depletion is to recycle biomass materials for energy storage devices. This study reports a unique and innovative solution to capitalize on a currently overlooked resource to produce high-performance lithium-sulfur (Li-S) batteries from recycled paper. The recycled paper fibers are creatively composited with graphene oxide sheets via a capillary adsorption method. The recycled paper/graphene oxide hybrid is then converted to activated paper carbon/reduced graphene oxide (APC/graphene) scaffold for sulfur infiltration. The assembled Li-APC/graphene/S battery exhibits a superior lifespan of 620 cycles with an excellent capacity retention rate of 60.5%. An APC interlayer is sandwiched between the Li anode and the separator to suppress the degradation of Li anode by preventing the nonhomogeneous growth of mossy Li whiskers, stretching the battery lifespan up to 1000 cycles with a capacitance retention rate of 52.3%. The capillary adsorption method coupled with the porous carbonaceous anode interlayer configuration creates a new opportunity for the development of batteries derived from porous biomass materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Programmable hydrogenation of graphene for novel nanocages

    NASA Astrophysics Data System (ADS)

    Zhang, Liuyang; Zeng, Xiaowei; Wang, Xianqiao

    2013-11-01

    Folded graphene has exhibited novel electrical and mechanical properties unmatched by pristine graphene, which implies that morphology of graphene adds the dimensionality of design space to tailor its properties. However, how to overcome the energy barrier of the folding process to fold the graphene with the specific morphology remains unexplored. Here we propose a programmable chemical functionalization by doping a pristine graphene sheet in a certain pattern with hydrogen atoms to precisely control its folding morphology. Molecular dynamics simulation has been performed to create a cross-shaped cubic graphene nanocage encapsulating a biomolecule by warping the top graphene layer downward and the bottom graphene layer upward to mimic the drug delivery vehicle. Such a paradigm, programmable enabled graphene nanocage, opens up a new avenue to control the 3D architecture of folded graphene and therefore provides a feasible way to exploit and fabricate the graphene-based unconventional nanomaterials and nanodevices for drug delivery.

  7. Graphene based biosensors

    SciTech Connect

    Gürel, Hikmet Hakan; Salmankurt, Bahadır

    2016-03-25

    Nanometer-sized graphene as a 2D material has unique chemical and electronic properties. Because of its unique physical, chemical, and electronic properties, its interesting shape and size make it a promising nanomaterial in many biological applications. It is expected that biomaterials incorporating graphene will be developed for the graphene-based drug delivery systems and biomedical devices. The interactions of biomolecules and graphene are long-ranged and very weak. Development of new techniques is very desirable for design of bioelectronics sensors and devices. In this work, we present first-principles calculations within density functional theory to calculate effects of charging on nucleobases on graphene. It is shown that how modify structural and electronic properties of nucleobases on graphene by applied charging.

  8. Dry spinning approach to continuous graphene fibers with high toughness.

    PubMed

    Tian, Qishi; Xu, Zhen; Liu, Yingjun; Fang, Bo; Peng, Li; Xi, Jiabin; Li, Zheng; Gao, Chao

    2017-08-31

    Graphene fiber (GF) has emerged as a new carbonaceous fiber species since graphene-based liquid crystals were discovered. The growing performances of GFs in terms of their mechanical performance and their functionalities have assured their extensive applications in structural materials and functional textiles. To date, many spinning strategies utilizing coagulation baths have been applied in GF, which necessitates a complicated washing process. Dry spinning is a more convenient and green method for use with fibers in the chemical fiber industry, and should be a good option for GFs; however, this technique has never been used in a system of GF. In this research, first the dry spinning technique was used to fabricate continuous GFs and the dry spun GFs showed good toughness and flexibility. The dry spinnability of graphene oxide liquid crystals was achieved by choosing dispersive solvents with low surface tension and high volatility. The dry spun neat GFs possessed high toughness up to 19.12 MJ m(-3), outperforming the wet spun neat GFs. This dry spinning methodology facilitates the green fabrication of fibers of graphene and graphene-beyond two-dimensional nanomaterials, and it may also be extended to other printing technologies for complex graphene architectures.

  9. Graphene-like single-layered covalent organic frameworks: synthesis strategies and application prospects.

    PubMed

    Liu, Xuan-He; Guan, Cui-Zhong; Wang, Dong; Wan, Li-Jun

    2014-10-29

    Two-dimensional (2D) nanomaterials, such as graphene and transition metal chalcogenides, show many interesting dimension-related materials properties. Inspired by the development of 2D inorganic nanomaterials, single-layered covalent organic frameworks (sCOFs), featuring atom-thick sheets and crystalline extended organic structures with covalently bonded building blocks, have attracted great attention in recent years. With their unique graphene-like topological structure and the merit of structural diversity, sCOFs promise to possess novel and designable properties. However, the synthesis of sCOFs with well-defined structures remains a great challenge. Herein, the recent development of the bottom-up synthesis methods of 2D sCOFs, such as thermodynamic equilibrium control methods, growth-kinetics control methods, and surface-assisted covalent polymerization methods, are reviewed. Finally, some of the critical properties and application prospects of these materials are outlined.

  10. Evaluation of in vivo graphene oxide toxicity for Acheta domesticus in relation to nanomaterial purity and time passed from the exposure.

    PubMed

    Dziewięcka, Marta; Karpeta-Kaczmarek, Julia; Augustyniak, Maria; Majchrzycki, Łukasz; Augustyniak-Jabłokow, Maria A

    2016-03-15

    Graphene and its oxidized form-graphene oxide (GO) have become exceptionally popular in industry and medicine due to their unique properties. However, there are suspicions that GO can cause adverse effects. Therefore, comprehensive knowledge on its potential toxicity is essential. This research assesses the in vivo toxicity of pure and manganese ion contaminated GO, which were injected into the hemolymph of Acheta domesticus. The activity of catalase (CAT) and gluthiathione peroxidases (GSTPx) as well as heat shock protein (HSP 70) and total antioxidant capacity (TAC) levels were measured at consecutive time points-1h, 24h, 48h and 72h after injection. Neither pure GO nor GO contaminated with manganese were neutral to the organism. The results proved the intensification of oxidative stress after GO injection, which was confirmed by increased enzyme activity. The organism seems to cope with this stress, especially in the first 24h after injection. In the following days, increasing HSP 70 levels were observed, which might suggest the synthesis of new proteins and the removal of old and damaged ones. With that in mind, the potential toxicity of the studied material, which could lead to serious and permanent damage to the organism, should still be taken into consideration. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Two-dimensional soft nanomaterials: a fascinating world of materials.

    PubMed

    Zhuang, Xiaodong; Mai, Yiyong; Wu, Dongqing; Zhang, Fan; Feng, Xinliang

    2015-01-21

    The discovery of graphene has triggered great interest in two-dimensional (2D) nanomaterials for scientists in chemistry, physics, materials science, and related areas. In the family of newly developed 2D nanostructured materials, 2D soft nanomaterials, including graphene, Bx Cy Nz nanosheets, 2D polymers, covalent organic frameworks (COFs), and 2D supramolecular organic nanostructures, possess great advantages in light-weight, structural control and flexibility, diversity of fabrication approaches, and so on. These merits offer 2D soft nanomaterials a wide range of potential applications, such as in optoelectronics, membranes, energy storage and conversion, catalysis, sensing, biotechnology, etc. This review article provides an overview of the development of 2D soft nanomaterials, with special highlights on the basic concepts, molecular design principles, and primary synthesis approaches in the context.

  12. Plasmonics of 2D Nanomaterials: Properties and Applications

    PubMed Central

    Li, Yu; Li, Ziwei; Chi, Cheng; Shan, Hangyong; Zheng, Liheng

    2017-01-01

    Plasmonics has developed for decades in the field of condensed matter physics and optics. Based on the classical Maxwell theory, collective excitations exhibit profound light‐matter interaction properties beyond classical physics in lots of material systems. With the development of nanofabrication and characterization technology, ultra‐thin two‐dimensional (2D) nanomaterials attract tremendous interest and show exceptional plasmonic properties. Here, we elaborate the advanced optical properties of 2D materials especially graphene and monolayer molybdenum disulfide (MoS2), review the plasmonic properties of graphene, and discuss the coupling effect in hybrid 2D nanomaterials. Then, the plasmonic tuning methods of 2D nanomaterials are presented from theoretical models to experimental investigations. Furthermore, we reveal the potential applications in photocatalysis, photovoltaics and photodetections, based on the development of 2D nanomaterials, we make a prospect for the future theoretical physics and practical applications. PMID:28852608

  13. Plasmonics of 2D Nanomaterials: Properties and Applications.

    PubMed

    Li, Yu; Li, Ziwei; Chi, Cheng; Shan, Hangyong; Zheng, Liheng; Fang, Zheyu

    2017-08-01

    Plasmonics has developed for decades in the field of condensed matter physics and optics. Based on the classical Maxwell theory, collective excitations exhibit profound light-matter interaction properties beyond classical physics in lots of material systems. With the development of nanofabrication and characterization technology, ultra-thin two-dimensional (2D) nanomaterials attract tremendous interest and show exceptional plasmonic properties. Here, we elaborate the advanced optical properties of 2D materials especially graphene and monolayer molybdenum disulfide (MoS2), review the plasmonic properties of graphene, and discuss the coupling effect in hybrid 2D nanomaterials. Then, the plasmonic tuning methods of 2D nanomaterials are presented from theoretical models to experimental investigations. Furthermore, we reveal the potential applications in photocatalysis, photovoltaics and photodetections, based on the development of 2D nanomaterials, we make a prospect for the future theoretical physics and practical applications.

  14. Recent applications of carbon nanomaterials in fluorescence biosensing and bioimaging.

    PubMed

    Wen, Jia; Xu, Yongqian; Li, Hongjuan; Lu, Aiping; Sun, Shiguo

    2015-07-21

    Carbon-based nanomaterials as important agents for biological applications have emerged in the past few years due to their unique optical, electronic, mechanical, and chemical properties. Many of these applications rely on successful surface modifications. This review article comprises two main parts. In the first part, we briefly review the properties and surface modifications of several classes of carbon nanomaterials, mainly carbon nanotubes (CNTs), graphene and its derivatives, carbon dots (CDs) and graphene quantum dots (GQDs), as well as some other forms of carbon-based nanomaterials such as fullerene, carbon nanohorns (CNHs) and carbon nanoonions (CNOs). In the second part, we focus on the biological applications of these carbon nanomaterials, in particular their applications for fluorescence biosensing as well as bioimaging.

  15. Nanomaterials for Sensor Applications

    SciTech Connect

    Márquez, Francisco; Morant, Carmen

    2015-01-15

    A large part of the advances in nanotechnology have been directed towards the development of highspeed electronics, more efficient catalysts, and sensors. This latter group of applications has great relevance and unprecedented development potential for the coming years. Some of the main objectives for the development of sensors have focused on making more sensitive, effective and specific sensing devices. The improvement of these systems and the increase of specificity are clearly associated with a decrease in size of the components, which can lead to obtaining more rapid action, almost in real time. Nanomaterials currently used in sensor development include a long list of nanostructured systems, as for example: Metal nanotubes, nanowires, nanofibers, nanocomposites, nanorods, nanoparticles, nanostructured polymers, and different allotropes of carbon as carbon nanotubes, graphene or fullerenes, among others [1]. These nanomaterials are characterized by having unique physicochemical properties, including high electrical and thermal conductivity, extremely high surface area/volume ratio, high mechanical strength and even excellent catalytic properties [1] [2]. These materials, may exhibit relevant physicochemical behavior, such as quantization or electronic confinement effects, which can be used in the development of all kinds of sensors [2]. So far, sensors have been developed for determination and quantification of gases, radiation, biomolecules, microorganisms, etc. [2] [3]. The sensors developed so far usually use the system lock and key, wherein the selective receptor (lock) is selectively anchored to the analyte of interest (or key). This system has great limitations when analyzing the analyte in the presence of other analytes, which can alter the sensitivity or specificity of the measure, as occurs in sensors used in biomedical applications [3] [4]. One possible solution is based on the development of sensor arrays, consisting of a combination of different and

  16. Nanomaterials for Sensor Applications

    DOE PAGES

    Márquez, Francisco; Morant, Carmen

    2015-01-15

    A large part of the advances in nanotechnology have been directed towards the development of highspeed electronics, more efficient catalysts, and sensors. This latter group of applications has great relevance and unprecedented development potential for the coming years. Some of the main objectives for the development of sensors have focused on making more sensitive, effective and specific sensing devices. The improvement of these systems and the increase of specificity are clearly associated with a decrease in size of the components, which can lead to obtaining more rapid action, almost in real time. Nanomaterials currently used in sensor development include amore » long list of nanostructured systems, as for example: Metal nanotubes, nanowires, nanofibers, nanocomposites, nanorods, nanoparticles, nanostructured polymers, and different allotropes of carbon as carbon nanotubes, graphene or fullerenes, among others [1]. These nanomaterials are characterized by having unique physicochemical properties, including high electrical and thermal conductivity, extremely high surface area/volume ratio, high mechanical strength and even excellent catalytic properties [1] [2]. These materials, may exhibit relevant physicochemical behavior, such as quantization or electronic confinement effects, which can be used in the development of all kinds of sensors [2]. So far, sensors have been developed for determination and quantification of gases, radiation, biomolecules, microorganisms, etc. [2] [3]. The sensors developed so far usually use the system lock and key, wherein the selective receptor (lock) is selectively anchored to the analyte of interest (or key). This system has great limitations when analyzing the analyte in the presence of other analytes, which can alter the sensitivity or specificity of the measure, as occurs in sensors used in biomedical applications [3] [4]. One possible solution is based on the development of sensor arrays, consisting of a combination of

  17. Nanomaterial-mediated Biosensors for Monitoring Glucose

    PubMed Central

    Taguchi, Masashige; Ptitsyn, Andre; McLamore, Eric S.

    2014-01-01

    Real-time monitoring of physiological glucose transport is crucial for gaining new understanding of diabetes. Many techniques and equipment currently exist for measuring glucose, but these techniques are limited by complexity of the measurement, requirement of bulky equipment, and low temporal/spatial resolution. The development of various types of biosensors (eg, electrochemical, optical sensors) for laboratory and/or clinical applications will provide new insights into the cause(s) and possible treatments of diabetes. State-of-the-art biosensors are improved by incorporating catalytic nanomaterials such as carbon nanotubes, graphene, electrospun nanofibers, and quantum dots. These nanomaterials greatly enhance biosensor performance, namely sensitivity, response time, and limit of detection. A wide range of new biosensors that incorporate nanomaterials such as lab-on-chip and nanosensor devices are currently being developed for in vivo and in vitro glucose sensing. These real-time monitoring tools represent a powerful diagnostic and monitoring tool for measuring glucose in diabetes research and point of care diagnostics. However, concerns over the possible toxicity of some nanomaterials limit the application of these devices for in vivo sensing. This review provides a general overview of the state of the art in nanomaterial-mediated biosensors for in vivo and in vitro glucose sensing, and discusses some of the challenges associated with nanomaterial toxicity. PMID:24876594

  18. Terahertz science and technology of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Hartmann, R. R.; Kono, J.; Portnoi, M. E.

    2014-08-01

    The diverse applications of terahertz (THz) radiation and its importance to fundamental science makes finding ways to generate, manipulate and detect THz radiation one of the key areas of modern applied physics. One approach is to utilize carbon nanomaterials, in particular, single-wall carbon nanotubes and graphene. Their novel optical and electronic properties offer much promise to the field of THz science and technology. This article describes the past, current, and future of THz science and technology of carbon nanotubes and graphene. We will review fundamental studies such as THz dynamic conductivity, THz nonlinearities and ultrafast carrier dynamics as well as THz applications such as THz sources, detectors, modulators, antennas and polarizers.

  19. Spiers Memorial Lecture. Advances of carbon nanomaterials.

    PubMed

    Ma, Lulu; Hart, Amelia H C; Ozden, Sehmus; Vajtai, Robert; Ajayan, Pulickel M

    2014-01-01

    During the last two decades the exciting properties of carbon nanomaterials, i.e. fullerene, carbon nanotubes and graphene, have drawn pronounced attention. This brief review will discuss the recent advances in the science and applications of nanocarbons, mainly of nanotubes and graphene, and the opportunities and challenges that exist in future technologies based on these emerging materials. The review will discuss the growth and selection, chemical modifications, substitutional doping, and engineering three-dimensional structures, and demonstrations of possible applications. This is a perspective on how the advent of nanocarbons will enable the development of the next generation of carbon materials and technologies relevant for a broad range of applications.

  20. Terahertz science and technology of carbon nanomaterials.

    PubMed

    Hartmann, R R; Kono, J; Portnoi, M E

    2014-08-15

    The diverse applications of terahertz (THz) radiation and its importance to fundamental science makes finding ways to generate, manipulate and detect THz radiation one of the key areas of modern applied physics. One approach is to utilize carbon nanomaterials, in particular, single-wall carbon nanotubes and graphene. Their novel optical and electronic properties offer much promise to the field of THz science and technology. This article describes the past, current, and future of THz science and technology of carbon nanotubes and graphene. We will review fundamental studies such as THz dynamic conductivity, THz nonlinearities and ultrafast carrier dynamics as well as THz applications such as THz sources, detectors, modulators, antennas and polarizers.

  1. Recent developments in carbon nanomaterial sensors.

    PubMed

    Baptista, Frederico R; Belhout, S A; Giordani, S; Quinn, S J

    2015-07-07

    Carbon nanomaterials are among the most broadly discussed, researched and applied of synthetic nanomaterials. The structural diversity of these materials provides an array of unique electronic, magnetic and optical properties, which when combined with their robust chemistry and ease of manipulation, makes them attractive candidates for sensor applications. Furthermore, the biocompatibility exhibited by many carbon nanomaterials has seen them used as in vivo biosensors. Carbon nanotubes, graphene and carbon dots have come under intense scrutiny, as either discrete molecular-like sensors, or as components which can be integrated into devices. In this review we consider recent developments in the use of carbon nanoparticles and nanostructures as sensors and consider how they can be used to detect a diverse range of analytes.

  2. Chemical Functionalization of Graphene Family Members

    NASA Astrophysics Data System (ADS)

    Vacchi, Isabella Anna; Ménard-Moyon, Cécilia; Bianco, Alberto

    2017-01-01

    Thanks to their outstanding physicochemical properties, graphene and its derivatives are interesting nanomaterials with a high potential in several fields. Graphene, graphene oxide, and reduced graphene oxide, however, differ partially in their characteristics due to their diverse surface composition. Those differences influence the chemical reactivity of these materials. In the following chapter the reactivity and main functionalization reactions performed on graphene, graphene oxide, and reduced graphene oxide are discussed. A part is also dedicated to the main analytical techniques used for characterization of these materials. Functionalization of graphene and its derivatives is highly important to modulate their characteristics and design graphene-based conjugates with novel properties. Functionalization can be covalent by forming strong and stable bonds with the graphene surface, or non-covalent via π-π, electrostatic, hydrophobic, and/or van der Waals interactions. Both types of functionalization are currently exploited.

  3. Graphene-based antibacterial paper.

    PubMed

    Hu, Wenbing; Peng, Cheng; Luo, Weijie; Lv, Min; Li, Xiaoming; Li, Di; Huang, Qing; Fan, Chunhai

    2010-07-27

    Graphene is a monolayer of tightly packed carbon atoms that possesses many interesting properties and has numerous exciting applications. In this work, we report the antibacterial activity of two water-dispersible graphene derivatives, graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets. Such graphene-based nanomaterials can effectively inhibit the growth of E. coli bacteria while showing minimal cytotoxicity. We have also demonstrated that macroscopic freestanding GO and rGO paper can be conveniently fabricated from their suspension via simple vacuum filtration. Given the superior antibacterial effect of GO and the fact that GO can be mass-produced and easily processed to make freestanding and flexible paper with low cost, we expect this new carbon nanomaterial may find important environmental and clinical applications.

  4. Nanomaterials Enabled Dye-sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Dong, Pei

    Dye sensitized solar cells (DSCs), as the third generation of solar cells, have attracted tremendous attention for their unique properties. The semi-transparent nature, low-cost, environmental friendliness, and convenient manufacturing conditions of this generation of solar cells are promising aspects of DSCs that make them competitive in their future applications. However, much improvement in many aspects of DSCs' is required for the realization of its full potential. In this thesis, various nanomaterials, such as graphene, multi wall carbon nanotubes, vertically aligned single wall carbon nanotubes, hybrid structures and etc, have been used to improve the performance of DSCs. First, the application of graphene covered metal grids as transparent conductive electrodes in DSCs is explored. It is demonstrated that the mechanical properties of these flexible hybrid transparent electrodes, in both bending and stretching tests, are better than their oxide-based counter parts. Moreover, different kinds of carbon nanotubes, for instance vertically aligned single wall carbon nanotubes, have been used as a replacement for traditional platinum counter electrodes, in both iodine electrolyte, and sulfide-electrolyte. Further, a flexible, seamlessly connected, 3-dimensional vertically-aligned few wall carbon nanotubes graphene hybrid structures on Ni foil as DSCs' counter electrodes improve their efficiency significantly. All these nanomaterials enabled DSCs architectures achieve a comparable or better performance than standard brittle platinum/fluorine doped tin oxide combination. The large surface area of such nanomaterials in addition to the high electrical conductivity and their mechanical robustness provides a platform for significant enhancements in DSCs' performance.

  5. Parameterizing water quality analysis and simulation program (WASP) for carbon-based nanomaterials

    EPA Science Inventory

    Carbon nanotubes (CNT) and graphenes are among the most popular carbon-based nanomaterials due to their unique electronic, mechanic and structural properties. Exposure modeling of these nanomaterials in the aquatic environment is necessary to predict the fate of these materials. ...

  6. Parameterizing water quality analysis and simulation program (WASP) for carbon-based nanomaterials

    EPA Science Inventory

    Carbon nanotubes (CNT) and graphenes are among the most popular carbon-based nanomaterials due to their unique electronic, mechanic and structural properties. Exposure modeling of these nanomaterials in the aquatic environment is necessary to predict the fate of these materials. ...

  7. A Novel Nanomaterial of Graphene Oxide Dotted with Ni Nanoparticles Produced by Supercritical CO2-Assisted Deposition for Reducing Friction and Wear.

    PubMed

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2015-06-03

    Graphene oxide dotted with nickel nanoparticles (Sc-Ni/GO) was synthesized by chemical deposition with the assistance of supercritical carbon dioxide (scCO2). The deposited Ni nanoparticles with diameters less than 5 nm are uniformly anchored on the surfaces of GO nanosheets. The as-prepared Sc-Ni/GO composites were employed as lubricating additives in paraffin oil and their tribological properties were tested using a four-ball tribometer. The results demonstrate that the Sc-Ni/GO composites are efficient lubricant additives. Adding 0.08 wt % Sc-Ni/GO into paraffin oil can reduce the friction coefficient and wear scar diameter by 32 and 42%, respectively, in comparison with the pure oil. In addition, Sc-Ni/GO composites exhibit superior lubricating performances than nano-Ni, GO nanosheets, and Ni/GO composites produced without the aid of scCO2. Such excellent lubricating properties of the Sc-Ni/GO composites derive from the synergistic lubricating actions of Ni nanoparticles and GO nanosheets during the rubbing process. The synergistic lubricating actions are closely related to the microstructure of the nanocomposites and the characteristic features of transfer film formed on the contact steel balls. The anchored Ni nanoparticles with smaller size and more uniform distribution on GO surfaces and the thin transfer film formed on the contact balls favor the full play of the synergistic actions.

  8. 25th anniversary article: hybrid nanostructures based on two-dimensional nanomaterials.

    PubMed

    Huang, Xiao; Tan, Chaoliang; Yin, Zongyou; Zhang, Hua

    2014-04-09

    Two-dimensional (2D) nanomaterials, such as graphene and transition metal dichalcogenides (TMDs), receive a lot of attention, because of their intriguing properties and wide applications in catalysis, energy-storage devices, electronics, optoelectronics, and so on. To further enhance the performance of their application, these 2D nanomaterials are hybridized with other functional nanostructures. In this review, the latest studies of 2D nanomaterial-based hybrid nanostructures are discussed, focusing on their preparation methods, properties, and applications.

  9. ECOTOXICOLOGY OF NANOMATERIALS

    EPA Science Inventory

    An overview of issues associated with potential ecological toxicity of nanomaterials with research needs outlined, current literature reviewed and discussion of nanomaterial toxicity relative to concerns that EPA and state risk assessors might have.

  10. ECOTOXICOLOGY OF NANOMATERIALS

    EPA Science Inventory

    An overview of issues associated with potential ecological toxicity of nanomaterials with research needs outlined, current literature reviewed and discussion of nanomaterial toxicity relative to concerns that EPA and state risk assessors might have.

  11. Water flattens graphene wrinkles: laser shock wrapping of graphene onto substrate-supported crystalline plasmonic nanoparticle arrays

    NASA Astrophysics Data System (ADS)

    Hu, Yaowu; Lee, Seunghyun; Kumar, Prashant; Nian, Qiong; Wang, Wenqi; Irudayaraj, Joseph; Cheng, Gary J.

    2015-11-01

    Hot electron injection into an exceptionally high mobility material can be realized in graphene-plasmonic nanoantenna hybrid nanosystems, which can be exploited for several front-edge applications including photovoltaics, plasmonic waveguiding and molecular sensing at trace levels. Wrinkling instabilities of graphene on these plasmonic nanostructures, however, would cause reactive oxygen or sulfur species to diffuse and react with the materials, decrease charge transfer rates and block intense hot-spots. No ex situ graphene wrapping technique has been explored so far to control these wrinkles. Here, we present a method to generate seamless integration by using water as a flyer to transfer the laser shock pressure to wrap graphene onto plasmonic nanocrystals. This technique decreases the interfacial gap between graphene and the covered substrate-supported plasmonic nanoparticle arrays by exploiting a shock pressure generated by the laser ablation of graphite and the water impermeable nature of graphene. Graphene wrapping of chemically synthesized crystalline gold nanospheres, nanorods and bipyramids with different field confinement capabilities is investigated. A combined experimental and computational method, including SEM and AFM morphological investigation, molecular dynamics simulation, and Raman spectroscopy characterization, is used to demonstrate the effectiveness of this technique. Graphene covered gold bipyramid exhibits the best result among the hybrid nanosystems studied. We have shown that the hybrid system fabricated by laser shock can be used for enhanced molecular sensing. The technique developed has the characteristics of tight integration, and chemical/thermal stability, is instantaneous in nature, possesses a large scale and room temperature processing capability, and can be further extended to integrate other 2D materials with various 0-3D nanomaterials.Hot electron injection into an exceptionally high mobility material can be realized in graphene

  12. Water flattens graphene wrinkles: laser shock wrapping of graphene onto substrate-supported crystalline plasmonic nanoparticle arrays.

    PubMed

    Hu, Yaowu; Lee, Seunghyun; Kumar, Prashant; Nian, Qiong; Wang, Wenqi; Irudayaraj, Joseph; Cheng, Gary J

    2015-12-21

    Hot electron injection into an exceptionally high mobility material can be realized in graphene-plasmonic nanoantenna hybrid nanosystems, which can be exploited for several front-edge applications including photovoltaics, plasmonic waveguiding and molecular sensing at trace levels. Wrinkling instabilities of graphene on these plasmonic nanostructures, however, would cause reactive oxygen or sulfur species to diffuse and react with the materials, decrease charge transfer rates and block intense hot-spots. No ex situ graphene wrapping technique has been explored so far to control these wrinkles. Here, we present a method to generate seamless integration by using water as a flyer to transfer the laser shock pressure to wrap graphene onto plasmonic nanocrystals. This technique decreases the interfacial gap between graphene and the covered substrate-supported plasmonic nanoparticle arrays by exploiting a shock pressure generated by the laser ablation of graphite and the water impermeable nature of graphene. Graphene wrapping of chemically synthesized crystalline gold nanospheres, nanorods and bipyramids with different field confinement capabilities is investigated. A combined experimental and computational method, including SEM and AFM morphological investigation, molecular dynamics simulation, and Raman spectroscopy characterization, is used to demonstrate the effectiveness of this technique. Graphene covered gold bipyramid exhibits the best result among the hybrid nanosystems studied. We have shown that the hybrid system fabricated by laser shock can be used for enhanced molecular sensing. The technique developed has the characteristics of tight integration, and chemical/thermal stability, is instantaneous in nature, possesses a large scale and room temperature processing capability, and can be further extended to integrate other 2D materials with various 0-3D nanomaterials.

  13. Ultrathin Tungsten Oxide Nanowires/Reduced Graphene Oxide Composites for Toluene Sensing.

    PubMed

    Hassan, Muhammad; Wang, Zhi-Hua; Huang, Wei-Ran; Li, Min-Qiang; Liu, Jian-Wei; Chen, Jia-Fu

    2017-09-29

    Graphene-based composites have gained great attention in the field of gas sensor fabrication due to their higher surface area with additional functional groups. Decorating one-dimensional (1D) semiconductor nanomaterials on graphene also show potential benefits in gas sensing applications. Here we demonstrate the one-pot and low cost synthesis of W18O49 NWs/rGO composites with different amount of reduced graphene oxide (rGO) which show excellent gas-sensing properties towards toluene and strong dependence on their chemical composition. As compared to pure W18O49 NWs, an improved gas sensing response (2.8 times higher) was achieved in case of W18O49 NWs composite with 0.5 wt. % rGO. Promisingly, this strategy can be extended to prepare other nanowire based composites with excellent gas-sensing performance.

  14. Price tag in nanomaterials?

    NASA Astrophysics Data System (ADS)

    Gkika, D. A.; Vordos, N.; Nolan, J. W.; Mitropoulos, A. C.; Vansant, E. F.; Cool, P.; Braet, J.

    2017-05-01

    With the evolution of the field of nanomaterials in the past number of years, it has become apparent that it will be key to future technological developments. However, while there are unlimited research undertakings on nanomaterials, limited research results on nanomaterial costs exist; all in spite of the generous funding that nanotechnology projects have received. There has recently been an exponential increase in the number of studies concerning health-related nanomaterials, considering the various medical applications of nanomaterials that drive medical innovation. This work aims to analyze the effect of the cost factor on acceptability of health-related nanomaterials independently or in relation to material toxicity. It appears that, from the materials studied, those used for cancer treatment applications are more expensive than the ones for drug delivery. The ability to evaluate cost implications improves the ability to undertake research mapping and develop opinions on nanomaterials that can drive innovation.

  15. Nanomaterial-based barcodes.

    PubMed

    Wang, Miao; Duong, Binh; Fenniri, Hicham; Su, Ming

    2015-07-14

    Two-dimensional (2D) barcodes ubiquitously used to label, track and authenticate objects face increasing challenges of being damaged, altered and falsified. The past effort in nanomaterials has paved the way for controlled synthesis of nanomaterials with desired size, shape and function. Due to their extremely small sizes, these nanomaterials are promising as next generation barcodes that can be added into or mixed with objects of interest without being noticed. These barcodes can be effectively read owing to their physical properties by manufacturers, law enforcement and security agencies. Meanwhile, nanomaterial-based barcodes are hard to reverse-engineer or imitate without advanced knowledge and technical expertise. This review describes how nanomaterials can be used as barcodes, discusses advantages and limitations of each type of nanomaterial-based barcode, and points out ways that could help design and prepare better nanomaterial-based barcodes.

  16. Immobilization techniques in the fabrication of nanomaterial-based electrochemical biosensors: a review.

    PubMed

    Putzbach, William; Ronkainen, Niina J

    2013-04-11

    The evolution of 1st to 3rd generation electrochemical biosensors reflects a simplification and enhancement of the transduction pathway. However, in recent years, modification of the transducer with nanomaterials has become increasingly studied and imparts many advantages. The sensitivity and overall performance of enzymatic biosensors has improved tremendously as a result of incorporating nanomaterials in their fabrication. Given the unique and favorable qualities of gold nanoparticles, graphene and carbon nanotubes as applied to electrochemical biosensors, a consolidated survey of the different methods of nanomaterial immobilization on transducer surfaces and enzyme immobilization on these species is beneficial and timely. This review encompasses modification of enzymatic biosensors with gold nanoparticles, carbon nanotubes, and graphene.

  17. Applications of graphene electrophoretic deposition. A review.

    PubMed

    Chavez-Valdez, A; Shaffer, M S P; Boccaccini, A R

    2013-02-14

    This Review summarizes research progress employing electrophoretic deposition (EPD) to fabricate graphene and graphene-based nanostructures for a wide range of applications, including energy storage materials, field emission devices, supports for fuel cells, dye-sensitized solar cells, supercapacitors and sensors, among others. These carbonaceous nanomaterials can be dispersed in organic solvents, or more commonly in water, using a variety of techniques compatible with EPD. Most deposits are produced under constant voltage conditions with deposition time also playing an important role in determining the morphology of the resulting graphene structures. In addition to simple planar substrates, it has been shown that uniform graphene-based layers can be deposited on three-dimensional, porous, and even flexible substrates. In general, electrophoretically deposited graphene layers show excellent properties, e.g., high electrical conductivity, large surface area, good thermal stability, high optical transparency, and robust mechanical strength. EPD also enables the fabrication of functional composite materials, e.g., graphene combined with metallic nanoparticles, with other carbonaceous materials (e.g., carbon nanotubes) or polymers, leading to novel nanomaterials with enhanced optical and electrical properties. In summary, the analysis of the available literature reveals that EPD is a simple and convenient processing method for graphene and graphene-based materials, which is easy to apply and versatile. EPD has, therefore, a promising future for applications in the field of advanced nanomaterials, which depend on the reliable manipulation of graphene and graphene-containing systems.

  18. Multi-functional carbon nanomaterials: Tailoring morphology for multidisciplinary applications

    SciTech Connect

    Dervishi, Enkeleda

    2015-05-14

    Carbon based nanomaterials are being developed to have many new properties and applications. Graphene, is a mono-layer 2D atomic thick structure formed from hexagons of carbon atoms bound together by sp^2hybrid bonds. A carbon nanotube (CNT) can be viewed as a sheet of graphene rolled up into a cylinder, usually 1-2 nanometers in diameter and a few microns thick. A few applications of graphene and carbon nanotubes include the development of Nanoelectronics, nanocomposite materials, Hydrogen storage and Li⁺ battery, etc.

  19. Nanomaterials for Electronics and Optoelectronics

    NASA Technical Reports Server (NTRS)

    Koehne, Jessica E.; Meyyappan, M.

    2011-01-01

    Nanomaterials such as carbon nanotubes(CNTs), graphene, and inorganic nanowires(INWs) have shown interesting electronic, mechanical, optical, thermal, and other properties and therefore have been pursued for a variety of applications by the nanotechnology community ranging from electronics to nanocomposites. While the first two are carbon-based materials, the INWs in the literature include silicon, germanium, III-V, II-VI, a variety of oxides, nitrides, antimonides and others. In this talk, first an overview of growth of these three classes of materials by CVD and PECVD will be presented along with results from characterization. Then applications in development of chemical sensors, biosensors, energy storage devices and novel memory architectures will be discussed.

  20. EDITORIAL: Whither nanomaterials? Whither nanomaterials?

    NASA Astrophysics Data System (ADS)

    Mallouk, Thomas E.; Pinkerton, Fred; Stetson, Ned

    2009-10-01

    As the journal Nanotechnology enters its third decade it is interesting to look back on the field and to think about where it may be headed in the future. The growth of the journal over the past twenty years mirrors that of the field, with exponentially rising numbers of citations and a widening diversity of topics that we identify as nanotechnology. In the early 1990s, Nanotechnology was focused primarily on nanoscale electronics and on scanning probe tools for fabricating and characterizing nanostructures. The synthesis and assembly of nanomaterials was already an active area in chemical research; however, it did not yet intersect strongly with the activities of the physics community, which was interested primarily in new phenomena that emerged on the nanoscale and on the devices that derived from them. In the 1990s there were several key advances that began to bridge this gap. Techniques were developed for making nanocrystals of compound semiconductors, oxides, and metals with very fine control over shape and superstructure. Carbon nanotubes were discovered and their unique electronic properties were demonstrated. Research on the self-assembly of organic molecules on surfaces led to the development of soft lithography and layer-by- layer assembly of materials. The potential to use DNA and then proteins as building blocks of precise assemblies of nanoparticles was explored. These bottom-up structures could not be made by top-down techniques, and their unique properties as components of sensors, electronic devices, biological imaging agents, and drug delivery vehicles began to change the definition of the field. Ten years ago, Inelke Malsch published a study on the scientific trends and organizational dynamics of nanotechology in Europe (1999 Nanotechnology 10 1-7). Scientists from a variety of disciplines were asked which areas of research they would include in the definition of nanotechnology. Although the article concluded with forward-looking thoughts in the

  1. Nanomaterial disposal by incineration.

    PubMed

    Holder, Amara L; Vejerano, Eric P; Zhou, Xinzhe; Marr, Linsey C

    2013-09-01

    As nanotechnology-based products enter into widespread use, nanomaterials will end up in disposal waste streams that are ultimately discharged to the environment. One possible end-of-life scenario is incineration. This review attempts to ascertain the potential pathways by which nanomaterials may enter incinerator waste streams and the fate of these nanomaterials during the incineration process. Although the literature on incineration of nanomaterials is scarce, results from studies of their behavior at high temperature or in combustion environments for other applications can help predict their fate within an incinerator. Preliminary evidence suggests nanomaterials may catalyze the formation or destruction of combustion by-products. Depending on their composition, nanomaterials may undergo physical and chemical transformations within the incinerator, impacting their partitioning within the incineration system (e.g., bottom ash, fly ash) and the effectiveness of control technology for removing them. These transformations may also drastically affect nanomaterial transport and impacts in the environment. Current regulations on incinerator emissions do not specifically address nanomaterials, but limits on particle and metal emissions may prove somewhat effective at reducing the release of nanomaterials in incinerator effluent. Control technology used to meet these regulations, such as fabric filters, electrostatic precipitators, and wet electrostatic scrubbers, are expected to be at least partially effective at removing nanomaterials from incinerator flue gas.

  2. Risk management of nanomaterials.

    PubMed

    Gwinn, Maureen R; Tran, Lang

    2010-01-01

    Nanotechnology has become the focus of a large amount of scientific, political, and financial interest. Limited information on the exposure to nanomaterials is available, with only a few occupational exposure studies having been performed. While laboratory animal studies on the biological effects of some nanomaterials have been published, no epidemiological studies have been reported to date. This lack of data on exposure and human health effects hinders risk assessment of these materials. As the use of nanomaterials increases rapidly, it is of vital importance that the risk assessment community understands the complexities of the issues surrounding the manufacture, use and disposal of nanomaterials, the potential of environmental and occupational exposure to human populations, as well as adverse health outcomes. For this to happen, it is in many ways necessary for the scientific community to also understand what questions risk assessors need to ask, and what research will best answer them. Risk management of nanomaterials requires more information as to the human and ecological effects of exposure to various nanomaterials. At this time, there are no specific regulations for nanomaterials, but a few efforts to include nanomaterials under existing environmental regulations have begun. The purpose of this article is to describe the potential regulations for nanomaterials, and the current issues related to the risk assessment of nanomaterials.

  3. Recent progress in application of carbon nanomaterials in laser desorption/ionization mass spectrometry.

    PubMed

    Wang, Jing; Liu, Qian; Liang, Yong; Jiang, Guibin

    2016-04-01

    Carbon nanomaterials have attracted great interest over past decades owing to their unique physical properties, versatile functionalization chemistry, and biological compatibility. In this article, we review recent progress in application of carbon nanomaterials in laser desorption/ionization mass spectrometry (LDI MS). Various types of carbon nanomaterials, including fullerenes, carbon nanotubes, graphene, carbon nanodots, nanodiamond, nanofibers, nanohorns, and their derivative forms, are involved. The applications of these materials as new matrices or probes in matrix-assisted or surface-enhanced laser desorption/ionization mass spectrometry (MALDI or SELDI MS) are discussed. Finally, we summarize current challenges and give our perspectives on the future of applications of carbon nanomaterials in LDI MS.

  4. Graphene and graphene-like two-denominational materials based fluorescence resonance energy transfer (FRET) assays for biological applications.

    PubMed

    Tian, Feng; Lyu, Jing; Shi, Jingyu; Yang, Mo

    2017-03-15

    In the past decades, Förster resonance energy transfer (FRET) has been applied in many biological applications to reveal the biological information at the nanoscale. Recently, graphene and graphene-like two-dimensional (2D) nanomaterials started to be used in FRET assays as donors or acceptors including graphene oxide (GO), graphene quantum dot (GQD), graphitic-carbon nitride nanosheets (g-C3N4) and transition metal dichalcogenides (e.g. MoS2, MnO2, and WS2). Due to the remarkable properties such as large surface to volume ratio, tunable energy band, photoluminescence and excellent biocompatibility, these 2D nanomaterials based FRET assays have shown great potential in various biological applications. This review summarizes the recent development of graphene and graphene-like 2D nanomaterials based FRET assays in applications of biosensing, bioimaging, and drug delivery monitoring. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Simulation of field-effect transistors and resonant tunneling diodes based on graphene

    NASA Astrophysics Data System (ADS)

    Abramov, Igor I.; Labunov, Vladimir A.; Kolomejtseva, Natali V.; Romanova, Irina A.

    2016-12-01

    Graphene is a nanomaterial that due to unique properties has attracted great interest for various applications, in particular, for development of nanoelectronic devices. In the paper the graphene field-effect transistors (GFET) and resonant tunneling diodes (RTD) are analyzed with the use of proposed models. First, simulation of dual-gate field-effect transistor based on monolayer graphene with the use of proposed combined model is considered. In the model the following important factors such as quantum capacitance, hole and electron mobility difference, drain and source resistances are taken into account. Investigations of dependence of a drain current on drain voltage for various top-gate-to-source voltages are performed. Influence of channel length, source and drain resistances on output characteristics of the device is analyzed. Comparison of calculation results with simulation ones obtained with the known models was carried out. Secondly, simulation of graphene-based nanostructures on hexagonal boron nitride, silicon carbide and silicon dioxide substrates was performed using proposed self-consistent numerical model, based on effective wave function formalism. The developed models in detail were described in our previous works. The possibility of using a proposed self-consistent model for double- and triple-barrier graphene-based RTD simulation was illustrated. As well as it was investigated the influence of different parameters on IV-characteristics of graphene-based RTDs. It was shown that it is necessary to take into account extended (passive) regions for adequate simulation of these devices.

  6. Rebar graphene.

    PubMed

    Yan, Zheng; Peng, Zhiwei; Casillas, Gilberto; Lin, Jian; Xiang, Changsheng; Zhou, Haiqing; Yang, Yang; Ruan, Gedeng; Raji, Abdul-Rahman O; Samuel, Errol L G; Hauge, Robert H; Yacaman, Miguel Jose; Tour, James M

    2014-05-27

    As the cylindrical sp(2)-bonded carbon allotrope, carbon nanotubes (CNTs) have been widely used to reinforce bulk materials such as polymers, ceramics, and metals. However, both the concept demonstration and the fundamental understanding on how 1D CNTs reinforce atomically thin 2D layered materials, such as graphene, are still absent. Here, we demonstrate the successful synthesis of CNT-toughened graphene by simply annealing functionalized CNTs on Cu foils without needing to introduce extraneous carbon sources. The CNTs act as reinforcing bar (rebar), toughening the graphene through both π-π stacking domains and covalent bonding where the CNTs partially unzip and form a seamless 2D conjoined hybrid as revealed by aberration-corrected scanning transmission electron microscopy analysis. This is termed rebar graphene. Rebar graphene can be free-standing on water and transferred onto target substrates without needing a polymer-coating due to the rebar effects of the CNTs. The utility of rebar graphene sheets as flexible all-carbon transparent electrodes is demonstrated. The in-plane marriage of 1D nanotubes and 2D layered materials might herald an electrical and mechanical union that extends beyond carbon chemistry.

  7. Rebar Graphene

    PubMed Central

    2015-01-01

    As the cylindrical sp2-bonded carbon allotrope, carbon nanotubes (CNTs) have been widely used to reinforce bulk materials such as polymers, ceramics, and metals. However, both the concept demonstration and the fundamental understanding on how 1D CNTs reinforce atomically thin 2D layered materials, such as graphene, are still absent. Here, we demonstrate the successful synthesis of CNT-toughened graphene by simply annealing functionalized CNTs on Cu foils without needing to introduce extraneous carbon sources. The CNTs act as reinforcing bar (rebar), toughening the graphene through both π–π stacking domains and covalent bonding where the CNTs partially unzip and form a seamless 2D conjoined hybrid as revealed by aberration-corrected scanning transmission electron microscopy analysis. This is termed rebar graphene. Rebar graphene can be free-standing on water and transferred onto target substrates without needing a polymer-coating due to the rebar effects of the CNTs. The utility of rebar graphene sheets as flexible all-carbon transparent electrodes is demonstrated. The in-plane marriage of 1D nanotubes and 2D layered materials might herald an electrical and mechanical union that extends beyond carbon chemistry. PMID:24694285

  8. Face the Edges: Catalytic Active Sites of Nanomaterials

    PubMed Central

    Ni, Bing

    2015-01-01

    Edges are special sites in nanomaterials. The atoms residing on the edges have different environments compared to those in other parts of a nanomaterial and, therefore, they may have different properties. Here, recent progress in nanomaterial fields is summarized from the viewpoint of the edges. Typically, edge sites in MoS2 or metals, other than surface atoms, can perform as active centers for catalytic reactions, so the method to enhance performance lies in the optimization of the edge structures. The edges of multicomponent interfaces present even more possibilities to enhance the activities of nanomaterials. Nanoframes and ultrathin nanowires have similarities to conventional edges of nanoparticles, the application of which as catalysts can help to reduce the use of costly materials. Looking beyond this, the edge structures of graphene are also essential for their properties. In short, the edge structure can influence many properties of materials. PMID:27980960

  9. Nanomaterials meet microfluidics.

    PubMed

    Pumera, Martin

    2011-05-28

    Nanomaterials and lab-on-a-chip platforms have undergone enormous development during the past decade. Here, we present an overview of how microfluidics benefited from the use of nanomaterials for the enhanced separation and detection of analytes. We also discuss how nanomaterials benefit from microfluidics in terms of synthesis and in terms of the simulation of environments for nanomotors and nanorobots. In our opinion, the "marriage" of nanomaterials and microfluidics is highly beneficial and is expected to solve vital challenges in related fields. © The Royal Society of Chemistry 2011

  10. Nanomaterials in preventive dentistry

    NASA Astrophysics Data System (ADS)

    Hannig, Matthias; Hannig, Christian

    2010-08-01

    The prevention of tooth decay and the treatment of lesions and cavities are ongoing challenges in dentistry. In recent years, biomimetic approaches have been used to develop nanomaterials for inclusion in a variety of oral health-care products. Examples include liquids and pastes that contain nano-apatites for biofilm management at the tooth surface, and products that contain nanomaterials for the remineralization of early submicrometre-sized enamel lesions. However, the treatment of larger visible cavities with nanomaterials is still at the research stage. Here, we review progress in the development of nanomaterials for different applications in preventive dentistry and research, including clinical trials.

  11. Carbon-based nanomaterials for tissue engineering.

    PubMed

    Ku, Sook Hee; Lee, Minah; Park, Chan Beum

    2013-02-01

    Carbon-based nanomaterials such as graphene sheets and carbon nanotubes possess unique mechanical, electrical, and optical properties that present new opportunities for tissue engineering, a key field for the development of biological alternatives that repair or replace whole or a portion of tissue. Carbon nanomaterials can also provide a similar microenvironment as like a biological extracellular matrix in terms of chemical composition and physical structure, making them a potential candidate for the development of artificial scaffolds. In this review, we summarize recent research advances in the effects of carbon nanomaterial-based substrates on cellular behaviors, including cell adhesion, proliferation, and differentiation into osteo- or neural- lineages. The development of 3D scaffolds based on carbon nanomaterials (or their composites with polymers and inorganic components) is introduced, and the potential of these constructs in tissue engineering, including toxicity issues, is discussed. Future perspectives and emerging challenges are also highlighted. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Virtual substrate method for nanomaterials characterization

    PubMed Central

    Da, Bo; Liu, Jiangwei; Yamamoto, Mahito; Ueda, Yoshihiro; Watanabe, Kazuyuki; Cuong, Nguyen Thanh; Li, Songlin; Tsukagoshi, Kazuhito; Yoshikawa, Hideki; Iwai, Hideo; Tanuma, Shigeo; Guo, Hongxuan; Gao, Zhaoshun; Sun, Xia; Ding, Zejun

    2017-01-01

    Characterization techniques available for bulk or thin-film solid-state materials have been extended to substrate-supported nanomaterials, but generally non-quantitatively. This is because the nanomaterial signals are inevitably buried in the signals from the underlying substrate in common reflection-configuration techniques. Here, we propose a virtual substrate method, inspired by the four-point probe technique for resistance measurement as well as the chop-nod method in infrared astronomy, to characterize nanomaterials without the influence of underlying substrate signals from four interrelated measurements. By implementing this method in secondary electron (SE) microscopy, a SE spectrum (white electrons) associated with the reflectivity difference between two different substrates can be tracked and controlled. The SE spectrum is used to quantitatively investigate the covering nanomaterial based on subtle changes in the transmission of the nanomaterial with high efficiency rivalling that of conventional core-level electrons. The virtual substrate method represents a benchmark for surface analysis to provide ‘free-standing' information about supported nanomaterials. PMID:28548114

  13. Virtual substrate method for nanomaterials characterization

    NASA Astrophysics Data System (ADS)

    da, Bo; Liu, Jiangwei; Yamamoto, Mahito; Ueda, Yoshihiro; Watanabe, Kazuyuki; Cuong, Nguyen Thanh; Li, Songlin; Tsukagoshi, Kazuhito; Yoshikawa, Hideki; Iwai, Hideo; Tanuma, Shigeo; Guo, Hongxuan; Gao, Zhaoshun; Sun, Xia; Ding, Zejun

    2017-05-01

    Characterization techniques available for bulk or thin-film solid-state materials have been extended to substrate-supported nanomaterials, but generally non-quantitatively. This is because the nanomaterial signals are inevitably buried in the signals from the underlying substrate in common reflection-configuration techniques. Here, we propose a virtual substrate method, inspired by the four-point probe technique for resistance measurement as well as the chop-nod method in infrared astronomy, to characterize nanomaterials without the influence of underlying substrate signals from four interrelated measurements. By implementing this method in secondary electron (SE) microscopy, a SE spectrum (white electrons) associated with the reflectivity difference between two different substrates can be tracked and controlled. The SE spectrum is used to quantitatively investigate the covering nanomaterial based on subtle changes in the transmission of the nanomaterial with high efficiency rivalling that of conventional core-level electrons. The virtual substrate method represents a benchmark for surface analysis to provide `free-standing' information about supported nanomaterials.

  14. Virtual substrate method for nanomaterials characterization.

    PubMed

    Da, Bo; Liu, Jiangwei; Yamamoto, Mahito; Ueda, Yoshihiro; Watanabe, Kazuyuki; Cuong, Nguyen Thanh; Li, Songlin; Tsukagoshi, Kazuhito; Yoshikawa, Hideki; Iwai, Hideo; Tanuma, Shigeo; Guo, Hongxuan; Gao, Zhaoshun; Sun, Xia; Ding, Zejun

    2017-05-26

    Characterization techniques available for bulk or thin-film solid-state materials have been extended to substrate-supported nanomaterials, but generally non-quantitatively. This is because the nanomaterial signals are inevitably buried in the signals from the underlying substrate in common reflection-configuration techniques. Here, we propose a virtual substrate method, inspired by the four-point probe technique for resistance measurement as well as the chop-nod method in infrared astronomy, to characterize nanomaterials without the influence of underlying substrate signals from four interrelated measurements. By implementing this method in secondary electron (SE) microscopy, a SE spectrum (white electrons) associated with the reflectivity difference between two different substrates can be tracked and controlled. The SE spectrum is used to quantitatively investigate the covering nanomaterial based on subtle changes in the transmission of the nanomaterial with high efficiency rivalling that of conventional core-level electrons. The virtual substrate method represents a benchmark for surface analysis to provide 'free-standing' information about supported nanomaterials.

  15. Electrodynamic Arrays Having Nanomaterial Electrodes

    NASA Technical Reports Server (NTRS)

    Trigwell, Steven (Inventor); Biris, Alexandru S. (Inventor); Calle, Carlos I. (Inventor)

    2013-01-01

    An electrodynamic array of conductive nanomaterial electrodes and a method of making such an electrodynamic array. In one embodiment, a liquid solution containing nanomaterials is deposited as an array of conductive electrodes on a substrate, including rigid or flexible substrates such as fabrics, and opaque or transparent substrates. The nanomaterial electrodes may also be grown in situ. The nanomaterials may include carbon nanomaterials, other organic or inorganic nanomaterials or mixtures.

  16. Genotoxicity investigations on nanomaterials.

    PubMed

    Oesch, Franz; Landsiedel, Robert

    2012-07-01

    This review is based on the lecture presented at the April 2010 nanomaterials safety assessment Postsatellite to the 2009 EUROTOX Meeting and summarizes genotoxicity investigations on nanomaterials published in the open scientific literature (up to 2008). Special attention is paid to the relationship between particle size and positive versus negative outcome, as well as the dependence of the outcome on the test used. Salient conclusions and outstanding recommendations emerging from the information summarized in this review are as follows: recognize that nanomaterials are not all the same; therefore know and document what nanomaterial has been tested and in what form; take nanomaterials specific properties into account; in order to make your results comparable with those of others and on other nanomaterials: use or at least include in your studies standardized methods; use in vivo studies to put in vitro results into perspective; take uptake and distribution of the nanomaterial into account; and in order to become able to make extrapolations to risk for human: learn about the mechanism of nanomaterials genotoxic effects. Past experience with standard non-nanosubstances already had shown that mechanisms of genotoxic effects can be complex and their elucidation can be demanding, while there often is an immediate need to assess the genotoxic hazard. Thus, a practical and pragmatic approach to genotoxicity investigations of novel nanomaterials is the use of a battery of standard genotoxicity testing methods covering a wide range of mechanisms. Application of these standard methods to nanomaterials demands, however, adaptations, and the interpretation of results from the genotoxicity testing of nanomaterials needs additional considerations exceeding those used for standard size materials.

  17. Nano-QSPR Modelling of Carbon-Based Nanomaterials Properties.

    PubMed

    Salahinejad, Maryam

    2015-01-01

    Evaluation of chemical and physical properties of nanomaterials is of critical importance in a broad variety of nanotechnology researches. There is an increasing interest in computational methods capable of predicting properties of new and modified nanomaterials in the absence of time-consuming and costly experimental studies. Quantitative Structure- Property Relationship (QSPR) approaches are progressive tools in modelling and prediction of many physicochemical properties of nanomaterials, which are also known as nano-QSPR. This review provides insight into the concepts, challenges and applications of QSPR modelling of carbon-based nanomaterials. First, we try to provide a general overview of QSPR implications, by focusing on the difficulties and limitations on each step of the QSPR modelling of nanomaterials. Then follows with the most significant achievements of QSPR methods in modelling of carbon-based nanomaterials properties and their recent applications to generate predictive models. This review specifically addresses the QSPR modelling of physicochemical properties of carbon-based nanomaterials including fullerenes, single-walled carbon nanotube (SWNT), multi-walled carbon nanotube (MWNT) and graphene.

  18. Nanomaterials and Retinal Toxicity

    EPA Science Inventory

    The neuroretina should be considered as a potential site of nanomaterial toxicity. Engineered nanomaterials may reach the retina through three potential routes of exposure including; intra­ vitreal injection of therapeutics; blood-borne delivery in the retinal vasculature an...

  19. Nanomaterials and Retinal Toxicity

    EPA Science Inventory

    The neuroretina should be considered as a potential site of nanomaterial toxicity. Engineered nanomaterials may reach the retina through three potential routes of exposure including; intra­ vitreal injection of therapeutics; blood-borne delivery in the retinal vasculature an...

  20. Phototoxicity of Selected Nanomaterials

    EPA Science Inventory

    Quantification of exposure to nanomaterials is critical for assessing their environmental hazard and risk. This is an immediate issue for nano-TiO2 because it is one of more common nanomaterials now in commerce, and is difficult to analyze using common acid-digestion techniques. ...

  1. Phototoxicity of Selected Nanomaterials

    EPA Science Inventory

    Quantification of exposure to nanomaterials is critical for assessing their environmental hazard and risk. This is an immediate issue for nano-TiO2 because it is one of more common nanomaterials now in commerce, and is difficult to analyze using common acid-digestion techniques. ...

  2. Molecular toxicity of nanomaterials.

    PubMed

    Chang, Xue-Ling; Yang, Sheng-Tao; Xing, Gengmei

    2014-10-01

    With the rapid developments in the fields of nanoscience and nanotechnlogy, more and more nanomaterials and their based consumer products have been used into our daily life. The safety concerns of nanomaterials have been well recognized by the scientific community and the public. Molecular mechanism of interactions between nanomaterials and biosystems is the most essential topic and final core of the biosafety. In the last two decades, nanotoxicology developed very fast and toxicity phenomena of nanomaterials have been reported. To achieve better understanding and detoxication of nanomaterials, thorough studies of nanotoxicity at molecular level are important. The interactions between nanomaterials and biomolecules have been widely investigated as the first step toward the molecular nanotoxicology. The consequences of such interactions have been discussed in the literature. Besides this, the chemical mechanism of nanotoxicology is gaining more attention, which would lead to a better design of nontoxic nanomaterials. In this review, we focus on the molecular nanotoxicology and explore the toxicity of nanomaterials at molecular level. The molecular level studies of nanotoxicology are summarized and the published nanotoxicological data are revisited.

  3. Nanomaterials in Biomedicine

    SciTech Connect

    Abdel-Wahhab, Mosaad A.; Márquez, Francisco

    2015-06-11

    Nowadays, nanomaterials have become an emerging field that has shown great promise in the development of novel diagnostic, imaging and therapeutic agents for a variety of diseases, including cancer, due to their nanoscale size effects and increased surface area. In comparison to their larger counterparts, nanomaterials have unique physicochemical and biological properties including size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility which can affect their interactions with biomolecules and cells. In addition, nanoparticles (NPs) with size-tunable light emission have demonstrated an impressive potential as high-efficiency delivery transporters for biomolecules into cells, being used to produce exceptional images of tumor sites. Moreover, NPs delivery system has been widely applied in pharmaceutical field to enhance absorption of bioactive compounds since they can interact with several phytochemicals by hydrogen bonds and hydrophobic interactions to encapsulate these phytochemicals in NPs and thus enhance aqueous solubility of the chemicals. Moreover, NPs also can prevent against oxidation/degradation of the phytochemicals encapsulated in the gastrointestinal tract and can be taken directly up by epithelial cells in the small intestine resulting in the increase of absorption and bioavailability of phytochemicals. In general, there are two specific fields of utilization of intrinsically active NPs as pharmacologic agents including oxidative-related pathologies and cancer. On the other hand, Redox active NPs have been shown to ameliorate many clinically relevant pathological disorders that implicate oxidative stress, reducing the oxidative burden and alleviating many important symptoms. In additionuch NPs act either in a catalytic way resembling the action of antioxidant enzymes such as catalase and superoxide dismutase, or as activating surfaces to facilitate reactions between the aqueous environment and the

  4. Nanomaterials in Biomedicine

    DOE PAGES

    Abdel-Wahhab, Mosaad A.; Márquez, Francisco

    2015-06-11

    Nowadays, nanomaterials have become an emerging field that has shown great promise in the development of novel diagnostic, imaging and therapeutic agents for a variety of diseases, including cancer, due to their nanoscale size effects and increased surface area. In comparison to their larger counterparts, nanomaterials have unique physicochemical and biological properties including size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility which can affect their interactions with biomolecules and cells. In addition, nanoparticles (NPs) with size-tunable light emission have demonstrated an impressive potential as high-efficiency delivery transporters for biomolecules into cells, being used to producemore » exceptional images of tumor sites. Moreover, NPs delivery system has been widely applied in pharmaceutical field to enhance absorption of bioactive compounds since they can interact with several phytochemicals by hydrogen bonds and hydrophobic interactions to encapsulate these phytochemicals in NPs and thus enhance aqueous solubility of the chemicals. Moreover, NPs also can prevent against oxidation/degradation of the phytochemicals encapsulated in the gastrointestinal tract and can be taken directly up by epithelial cells in the small intestine resulting in the increase of absorption and bioavailability of phytochemicals. In general, there are two specific fields of utilization of intrinsically active NPs as pharmacologic agents including oxidative-related pathologies and cancer. On the other hand, Redox active NPs have been shown to ameliorate many clinically relevant pathological disorders that implicate oxidative stress, reducing the oxidative burden and alleviating many important symptoms. In additionuch NPs act either in a catalytic way resembling the action of antioxidant enzymes such as catalase and superoxide dismutase, or as activating surfaces to facilitate reactions between the aqueous environment

  5. Suppression of copper thin film loss during graphene synthesis.

    PubMed

    Lee, Alvin L; Tao, Li; Akinwande, Deji

    2015-01-28

    Thin metal films can be used to catalyze the growth of nanomaterials in place of the bulk metal, while greatly reducing the amount of material used. A big drawback of copper thin films (0.5-1.5 μm thick) is that, under high temperature/vacuum synthesis, the mass loss of films severely reduces the process time due to discontinuities in the metal film, thereby limiting the time scale for controlling metal grain and film growth. In this work, we have developed a facile method, namely "covered growth" to extend the time copper thin films can be exposed to high temperature/vacuum environment for graphene synthesis. The key to preventing severe mass loss of copper film during the high temperature chemical vapor deposition (CVD) process is to have a cover piece on top of the growth substrate. This new "covered growth" method enables the high-temperature annealing of the copper film upward of 4 h with minimal mass loss, while increasing copper film grain and graphene domain size. Graphene was then successfully grown on the capped copper film with subsequent transfer for device fabrication. Device characterization indicated equivalent physical, chemical, and electrical properties to conventional CVD graphene. Our "covered growth" provides a convenient and effective solution to the mass loss issue of thin films that serve as catalysts for a variety of 2D material syntheses.

  6. The rational designed graphene oxide-Fe2O3 composites with low cytotoxicity.

    PubMed

    Yan, Dong; Zhao, Haiyan; Pei, Jiayun; Wu, Xin; Liu, Yue

    2017-03-01

    Novel two-dimensional materials with a layered structure are of special interest for a variety of promising applications. In current research, the nanostructured graphene oxide-Fe2O3 composite (GO-Fe2O3) was firstly obtained via a carefully elaborated approach of vacuum freeze-drying. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images revealed that α-Fe2O3 nanoparticles loaded well on the surfaces of graphene. A series of characterization were performed to further elucidate the as-obtained nanomaterial's physicochemical properties. These results suggested the current route could be further extended to obtain the other kinds of two-dimensional materials based composites. For the sake of extending the potential application of herein achieved graphene composites, its cytotoxicity assessment on HeLa cells was systematically investigated. CCK-8 assay in HeLa cells treated by GO-Fe2O3 showed dose- (1-100μg/ml) and time- (24-48h) dependent cytotoxicity, which was comparable to that of GO. The excess generation of intracellular reactive oxygen species (ROS) induced by these nanomaterials was responsible for the cytotoxicity. TEM analysis vividly illustrated GO-Fe2O3 internalized by HeLa cells in endomembrane compartments such as lysosomes, and degraded through autophagic pathway. The detrimental biological consequence accompanied by cell internalization was limited. Based on the above results, it expected to render useful information for the development of new and popular strategies to design graphene-based composites, as well as deep insights into the mechanism of graphene-based composites cytotoxicity for further potential application. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Carbon nanomaterials for electronics, optoelectronics, photovoltaics, and sensing.

    PubMed

    Jariwala, Deep; Sangwan, Vinod K; Lauhon, Lincoln J; Marks, Tobin J; Hersam, Mark C

    2013-04-07

    In the last three decades, zero-dimensional, one-dimensional, and two-dimensional carbon nanomaterials (i.e., fullerenes, carbon nanotubes, and graphene, respectively) have attracted significant attention from the scientific community due to their unique electronic, optical, thermal, mechanical, and chemical properties. While early work showed that these properties could enable high performance in selected applications, issues surrounding structural inhomogeneity and imprecise assembly have impeded robust and reliable implementation of carbon nanomaterials in widespread technologies. However, with recent advances in synthesis, sorting, and assembly techniques, carbon nanomaterials are experiencing renewed interest as the basis of numerous scalable technologies. Here, we present an extensive review of carbon nanomaterials in electronic, optoelectronic, photovoltaic, and sensing devices with a particular focus on the latest examples based on the highest purity samples. Specific attention is devoted to each class of carbon nanomaterial, thereby allowing comparative analysis of the suitability of fullerenes, carbon nanotubes, and graphene for each application area. In this manner, this article will provide guidance to future application developers and also articulate the remaining research challenges confronting this field.

  8. The effect of pristine carbon-based nanomaterial on the growth of green gram sprouts and pH of water

    PubMed Central

    2014-01-01

    We examined the toxicity of four carbon-based nanomaterials (unmodified) by using carbon quantum dots (CQDs), graphene quantum dots (GQDs), graphene oxide (GO), and single-walled carbon nanotubes (SWCNTs) to cultivate bean sprout. Results showed that the toxicity of these four carbon nanomaterials increases with the increasing of concentration and cultivating time. In addition, pH test was applied to study the effect of carbon-based nanomaterials on water. pH of culture solution displayed unconspicuous dose-dependent, but nanomaterials indeed have a considerable impact on the pH even at low concentration. PMID:25346649

  9. The effect of pristine carbon-based nanomaterial on the growth of green gram sprouts and pH of water

    NASA Astrophysics Data System (ADS)

    Li, Xiaolin; Zhou, Zhihua; Lu, Dejiong; Dong, Xinwei; Xu, Minghan; Wei, Liangming; Zhang, Yafei

    2014-10-01

    We examined the toxicity of four carbon-based nanomaterials (unmodified) by using carbon quantum dots (CQDs), graphene quantum dots (GQDs), graphene oxide (GO), and single-walled carbon nanotubes (SWCNTs) to cultivate bean sprout. Results showed that the toxicity of these four carbon nanomaterials increases with the increasing of concentration and cultivating time. In addition, pH test was applied to study the effect of carbon-based nanomaterials on water. pH of culture solution displayed unconspicuous dose-dependent, but nanomaterials indeed have a considerable impact on the pH even at low concentration.

  10. Biological applications of graphene oxide

    SciTech Connect

    Gürel, Hikmet Hakan; Salmankurt, Bahadır

    2016-03-25

    Graphene as a 2D material has unique chemical and electronic properties. Because of its unique physical, chemical, and electronic properties, its interesting shape and size make it a promising nanomaterial in many biological applications. However, the lower water-solubility and the irreversible aggregation due to the strong π-π stacking hinder the wide application of graphene nanosheets in biomedical field. Thus, graphene oxide (GO), one derivative of graphene, has been used more frequently in the biological system owing to its relatively higher water solubility and biocompatibility. Recently, it has been demonstrated that nanomaterials with different functional groups on the surface can be used to bind the drug molecules with high affinity. GO has different functional groups such as H, OH and O on its surface; it can be a potential candidate as a drug carrier. The interactions of biomolecules and graphene like structures are long-ranged and very weak. Development of new techniques is very desirable for design of bioelectronics sensors and devices. In this work, we present first-principles spin polarized calculations within density functional theory to calculate effects of charging on DNA/RNA nucleobases on graphene oxide. It is shown that how modify structural and electronic properties of nucleobases on graphene oxide by applied charging.

  11. Enzyme-catalyzed degradation of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Kotchey, Gregg P.

    Carbon nanotubes and graphene, the nanoscale sp 2 allotropes of carbon, have garnered widespread attention as a result of their remarkable electrical, mechanical, and optical properties and the promise of new technologies that harness these properties. Consequently, these carbon nanomaterials (CNMs) have been employed for diverse applications such as electronics, sensors, composite materials, energy conversion devices, and nanomedicine. The manufacture and eventual disposal of these products may result in the release of CNMs into the environment and subsequent exposure to humans, animals, and vegetation. Given the possible pro-inflammatory and toxic effects of CNMs, much attention has been focused on the distribution, toxicity, and persistence of CNMs both in living systems and the environment. This dissertation will guide the reader though recent studies aimed at elucidating fundamental insight into the persistence of CNMs such as carbon nanotubes (CNTs) and graphene derivatives (i.e., graphene oxide and reduced graphene oxide). In particular, in-testtube oxidation/degradation of CNMs catalyzed by peroxidase enzymes will be examined, and the current understanding of the mechanisms underlying these processes will be discussed. Finally, an outlook of the current field including in vitro and in vivo biodegradation experiments, which have benefits in terms of human health and environmental safety, and future directions that could have implications for nanomedical applications such as imaging and drug delivery will be presented. Armed with an understanding of how and why CNMs undergo enzyme-catalyzed oxidation/biodegradation, researchers can tailor the structure of CNMs to either promote or inhibit these processes. For example, in nanomedical applications such as drug delivery, the incorporation of carboxylate functional groups could facilitate biodegradation of the nanomaterial after delivery of the cargo. Also, the incorporation of CNMs with defect sites in consumer

  12. Ab initio study on the noncovalent adsorption of camptothecin anticancer drug onto graphene, defect modified graphene and graphene oxide

    NASA Astrophysics Data System (ADS)

    Saikia, Nabanita; Deka, Ramesh C.

    2013-09-01

    The application of graphene and related nanomaterials like boron nitride (BN) nanosheets, BN-graphene hybrid nanomaterials, and graphene oxide (GO) for adsorption of anticancer chemotherapeutic camptothecin (CPT) along with the effect on electronic properties prior to functionalization and after functionalization has been reported using density functional theory (DFT) calculations. The inclusion of dispersion correction to DFT is instrumental in accounting for van der Waals π-π stacking between CPT and the nanomaterial. The adsorption of CPT exhibits significant strain within the nanosheets and noncovalent adsorption of CPT is thermodynamically favoured onto the nanosheets. In case of GO, surface incorporation of functional groups result in significant crumpling along the basal plane and the interaction is basically mediated by H-bonding rather than π- π stacking. Docking studies predict the plausible binding of CPT, CPT functionalized graphene and GO with topoisomerase I (top 1) signifying that CPT interacts through π stacking with AT and GC base pairs of DNA and in presence of nano support, DNA bases preferentially gets bound to the basal plane of graphene and GO rather than the edges. At a theoretical level of understanding, our studies point out the noncovalent interaction of CPT with graphene based nanomaterials and GO for loading and delivery of anticancer chemotherapeutic along with active binding to Top1 protein.

  13. Synthesis of water soluble graphene.

    PubMed

    Si, Yongchao; Samulski, Edward T

    2008-06-01

    A facile and scalable preparation of aqueous solutions of isolated, sparingly sulfonated graphene is reported. (13)C NMR and FTIR spectra indicate that the bulk of the oxygen-containing functional groups was removed from graphene oxide. The electrical conductivity of thin evaporated films of graphene (1250 S/m) relative to similarly prepared graphite (6120 S/m) implies that an extended conjugated sp (2) network is restored in the water soluble graphene.

  14. Nanomaterials for Environmental Remediation

    SciTech Connect

    Fryxell, Glen E.; Mattigod, Shas V.

    2006-01-30

    Over the last 10-15 years, there has been an explosion of activity in the design and synthesis of nanomaterials built around a wide variety of basic architectures. In more recent years, a portion of this effort has focused on the environmental impacts and environmental applications of these nanomaterials. Why all this interest in nanomaterials? What advantages might these tiny structures provide to environmental remediation efforts? This chapter is intended to provide an overview of research in this area, as well as outline some of the advantages that these materials provide to environmental clean-up efforts.

  15. Specific heat and thermal conductivity of nanomaterials

    NASA Astrophysics Data System (ADS)

    Bhatt, Sandhya; Kumar, Raghuvesh; Kumar, Munish

    2017-01-01

    A model is proposed to study the size and shape effects on specific heat and thermal conductivity of nanomaterials. The formulation developed for specific heat is based on the basic concept of cohesive energy and melting temperature. The specific heat of Ag and Au nanoparticles is reported and the effect of size and shape has been studied. We observed that specific heat increases with the reduction of particle size having maximum shape effect for spherical nanoparticle. To provide a more critical test, we extended our model to study the thermal conductivity and used it for the study of Si, diamond, Cu, Ni, Ar, ZrO2, BaTiO3 and SrTiO3 nanomaterials. A significant reduction is found in the thermal conductivity for nanomaterials by decreasing the size. The model predictions are consistent with the available experimental and simulation results. This demonstrates the suitability of the model proposed in this paper.

  16. Graphene based enzymatic bioelectrodes and biofuel cells.

    PubMed

    Karimi, Anahita; Othman, Ali; Uzunoglu, Aytekin; Stanciu, Lia; Andreescu, Silvana

    2015-04-28

    The excellent electrical conductivity and ease of functionalization make graphene a promising material for use in enzymatic bioelectrodes and biofuel cells. Enzyme based biofuel cells have attracted substantial interest due to their potential to harvest energy from organic materials. This review provides an overview of the functional properties and applications of graphene in the construction of biofuel cells as alternative power sources. The review covers the current state-of-the-art research in graphene based nanomaterials (physicochemical properties and surface functionalities), the role of these parameters in enhancing electron transfer, the stability and activity of immobilized enzymes, and how enhanced power density can be achieved. Specific examples of enzyme immobilization methods, enzyme loading, stability and function on graphene, functionalized graphene and graphene based nanocomposite materials are discussed along with their advantages and limitations. Finally, a critical evaluation of the performance of graphene based enzymatic biofuel cells, the current status, challenges and future research needs are provided.

  17. Graphene based enzymatic bioelectrodes and biofuel cells

    NASA Astrophysics Data System (ADS)

    Karimi, Anahita; Othman, Ali; Uzunoglu, Aytekin; Stanciu, Lia; Andreescu, Silvana

    2015-04-01

    The excellent electrical conductivity and ease of functionalization make graphene a promising material for use in enzymatic bioelectrodes and biofuel cells. Enzyme based biofuel cells have attracted substantial interest due to their potential to harvest energy from organic materials. This review provides an overview of the functional properties and applications of graphene in the construction of biofuel cells as alternative power sources. The review covers the current state-of-the-art research in graphene based nanomaterials (physicochemical properties and surface functionalities), the role of these parameters in enhancing electron transfer, the stability and activity of immobilized enzymes, and how enhanced power density can be achieved. Specific examples of enzyme immobilization methods, enzyme loading, stability and function on graphene, functionalized graphene and graphene based nanocomposite materials are discussed along with their advantages and limitations. Finally, a critical evaluation of the performance of graphene based enzymatic biofuel cells, the current status, challenges and future research needs are provided.

  18. Electrowetting on dielectric experiments using graphene

    NASA Astrophysics Data System (ADS)

    Tan, Xuebin; Zhou, Zhixian; Ming-Cheng Cheng, Mark

    2012-09-01

    We report electrowetting on dielectric (EWOD) experiments using graphene; a transparent, flexible and stretchable nanomaterial. Graphene sheets were synthesized by chemical vapor deposition, and transferred to various substrates (including glass slides and PET films). Reversible contact angle changes were observed on the Teflon-coated graphene electrode with both AC and DC voltages. Nyquist plots of the EWOD reveal that the graphene electrode has higher capacitive impedance than gold electrodes under otherwise identical conditions, suggesting a lower density of pin-holes and defects in the Teflon/graphene electrode than in the Teflon/gold electrode. Furthermore, we have observed reduced electrolysis of the electrolyte and smaller leakage current in the dielectric layer (Teflon) on graphene electrodes than on Au electrodes at the same Teflon thickness and applied voltage. We expect that the improved EWOD properties using graphene as an electrode material will open the door to various applications, including flexible displays and droplet manipulation in three-dimensional microfluidics.

  19. Emerging frontiers of graphene in biomedicine.

    PubMed

    Byun, Jonghoe

    2015-02-01

    Graphene is a next-generation biomaterial with increasing biomedical applicability. As a new class of one-atom-thick nanosheets, it is a true two-dimensional honeycomb network nanomaterial that attracts interest in various scientific fields and is rapidly becoming the most widely studied carbon-based material. Since its discovery in 2004, its unique optical, mechanical, electronic, thermal, and magnetic properties are the basis of exploration of the potential applicability of graphene. Graphene materials, such as graphene oxide and its reduced form, are studied extensively in the biotechnology arena owing to their multivalent functionalization and efficient surface loading with various biomolecules. This review provides a brief summary of the recent progress in graphene and graphene oxide biological research together with current findings to spark novel applications in biomedicine. Graphene-based applications are progressively developing; hence, the opportunities and challenges of this rapidly growing field are discussed together with the versatility of these multifaceted materials.

  20. Graphene cardboard: From ripples to tunable metamaterial

    NASA Astrophysics Data System (ADS)

    Koskinen, Pekka

    2014-03-01

    Recently, graphene was introduced with tunable ripple texturing, a nanofabric enabled by graphene's remarkable elastic properties. However, one can further envision sandwiching the ripples, thus constructing composite nanomaterial, graphene cardboard. Here, the basic mechanical properties of such structures are investigated computationally. It turns out that graphene cardboard is highly tunable material, for its elastic figures of merit vary orders of magnitude, with Poisson ratio tunable from 10 to -0.5 as one example. These trends set a foundation to guide the design and usage of metamaterials made of rippled van der Waals solids.

  1. Solution-Based Processing of Monodisperse Two-Dimensional Nanomaterials.

    PubMed

    Kang, Joohoon; Sangwan, Vinod K; Wood, Joshua D; Hersam, Mark C

    2017-04-18

    Exfoliation of single-layer graphene from bulk graphite and the subsequent discovery of exotic physics and emergent phenomena in the atomically thin limit has motivated the isolation of other two-dimensional (2D) layered nanomaterials. Early work on isolated 2D nanomaterial flakes has revealed a broad range of unique physical and chemical properties with potential utility in diverse applications. For example, the electronic and optical properties of 2D nanomaterials depend strongly on atomic-scale variations in thickness, enabling enhanced performance in optoelectronic technologies such as light emitters, photodetectors, and photovoltaics. Much of the initial research on 2D nanomaterials has relied on micromechanical exfoliation, which yields high-quality 2D nanomaterial flakes that are suitable for fundamental studies but possesses limited scalability for real-world applications. In an effort to overcome this limitation, solution-processing methods for isolating large quantities of 2D nanomaterials have emerged. Importantly, solution processing results in 2D nanomaterial dispersions that are amenable to roll-to-roll fabrication methods that underlie lost-cost manufacturing of thin-film transistors, transparent conductors, energy storage devices, and solar cells. Despite these advantages, solution-based exfoliation methods typically lack control over the lateral size and thickness of the resulting 2D nanomaterial flakes, resulting in polydisperse dispersions with heterogeneous properties. Therefore, post-exfoliation separation techniques are needed to achieve 2D nanomaterial dispersions with monodispersity in lateral size, thickness, and properties. In this Account, we survey the latest developments in solution-based separation methods that aim to produce monodisperse dispersions and thin films of emerging 2D nanomaterials such as graphene, boron nitride, transition metal dichalcogenides, and black phosphorus. First, we motivate the need for precise thickness

  2. Minimizing Oxidation and Stable Nanoscale Dispersion Improves the Biocompatibility of Graphene in the Lung

    PubMed Central

    Duch, Matthew C.; Scott Budinger, G. R.; Liang, Yu Teng; Soberanes, Saul; Urich, Daniela; Chiarella, Sergio E.; Campochiaro, Laura A; Gonzalez, Angel; Chandel, Navdeep S.; Hersam, Mark C.; Mutlu, Gökhan M.

    2011-01-01

    To facilitate the proposed use of graphene and its derivative graphene oxide (GO) in widespread applications, we explored strategies that improve the biocompatibility of graphene nanomaterials in the lung. In particular, solutions of aggregated graphene, Pluronic dispersed graphene, and GO were administered directly into the lungs of mice. The introduction of GO resulted in severe and persistent lung injury. Furthermore, in cells, GO increased the rate of mitochondrial respiration and the generation of reactive oxygen species, activating inflammatory and apoptotic pathways. In contrast, this toxicity was significantly reduced in the case of pristine graphene after liquid phase exfoliation, and was further minimized when the unoxidized graphene was well-dispersed with the block copolymer Pluronic. Our results demonstrate that the covalent oxidation of graphene is a major contributor to its pulmonary toxicity and suggest that dispersion of pristine graphene in Pluronic provides a pathway for the safe handling and potential biomedical application of two-dimensional carbon nanomaterials. PMID:22023654

  3. Applications of Nanomaterials in Food Packaging.

    PubMed

    Bumbudsanpharoke, Nattinee; Choi, Jungwook; Ko, Seonghyuk

    2015-09-01

    Nanomaterials have drawn great interest in recent years due to their extraordinary properties that make them advantageous in food packaging applications. Specifically, nanoparticles can impart significant barrier properties, as well as mechanical, optical, catalytic, and antimicrobial properties into packaging. Silver nanoparticles (AgNPs) and nanoclay account for the majority of the nano-enabled food packaging on the market, while others, such as nano-zinc oxide (ZnO) and titanium, share less of the current market. In current food packaging, these nanomaterials are primarily used to impart antimicrobial function and to improve barrier properties, thereby extending the shelf life and freshness of packaged food. On the other hand, there is growing concern about the migration of nanomaterials from food contact materials to foodstuffs and its associated potential risks. Indeed, insufficient data about environmental and human safety assessments of migration and exposure of nanomaterials are hindering their market growth. To overcome this barrier, the public believes that legislation from government agencies is critical. This review provides an overview of the characteristics and functions of major nanomaterials that are commonly applied to food packaging, including available and near- future products. Migration research, safety issues, and public concerns are also discussed.

  4. Hybrid 2D-nanomaterials-based electrochemical immunosensing strategies for clinical biomarkers determination.

    PubMed

    Campuzano, S; Pedrero, M; Nikoleli, G-P; Pingarrón, J M; Nikolelis, D P

    2017-03-15

    Owing to the outstanding conductivity and biocompatibility as well as numerous other fascinating properties of two-dimensional (2D)-nanomaterials, 2D-based nanohybrids have shown unparalleled superiorities in the field of electrochemical biosensors. This review highlights latest advances in electrochemical immunosensors for clinical biomarkers based on different hybrid 2D-nanomaterials. Particular attention will be given to hybrid nanostructures involving graphene and other graphene-like 2D-layered nanomaterials (GLNs). Several recent strategies for using such 2D-nanomaterial heterostructures in the development of modern immunosensors, both for tagging or modifying electrode transducers, are summarized and discussed. These hybrid nanocomposites, quite superior than their rival materials, will undoubtedly have an important impact within the near future and not only in clinical areas. Current challenges and future perspectives in this rapidly growing field are also outlined.

  5. Potential risks of nanomaterials

    NASA Astrophysics Data System (ADS)

    Bakalova, Totka; Louda, Petr

    2014-05-01

    Nanotechnology is the design and manipulation of materials at the nanometer scale such that novel or enhanced properties emerge. It is a new area of knowledge that promises a dazzling array of opportunities in areas as diverse as manufacturing, energy, health care, and waste treatment. But while the ability to develop nanomaterials and incorporate them into products is advancing rapidly, our understanding of the potential environmental, health, and safety effects of nanomaterials — and of the most effective ways to manage such effects — has proceeded at a much slower pace. Because of the novel properties that emerge at the nano scale, nanomaterials may require more and different information than called for under traditional risk management systems. And given the enormous commercial and societal benefits that may potentially come from this technology, it is likely that nanomaterials, and the products and other applications containing them, will be widely produced and used. Therefore it is especially important to understand and minimize the potential risks.

  6. Food decontamination using nanomaterials

    USDA-ARS?s Scientific Manuscript database

    The research indicates that nanomaterials including nanoemulsions are promising decontamination media for the reduction of food contaminating pathogens. The inhibitory effect of nanoparticles for pathogens could be due to deactivate cellular enzymes and DNA; disrupting of membrane permeability; and/...

  7. Recent advances in applications of nanomaterials for sample preparation.

    PubMed

    Xu, Linnan; Qi, Xiaoyue; Li, Xianjiang; Bai, Yu; Liu, Huwei

    2016-01-01

    Sample preparation is a key step for qualitative and quantitative analysis of trace analytes in complicated matrix. Along with the rapid development of nanotechnology in material science, numerous nanomaterials have been developed with particularly useful applications in analytical chemistry. Benefitting from their high specific areas, increased surface activities, and unprecedented physical/chemical properties, the potentials of nanomaterials for rapid and efficient sample preparation have been exploited extensively. In this review, recent progress of novel nanomaterials applied in sample preparation has been summarized and discussed. Both nanoparticles and nanoporous materials are evaluated for their unusual performance in sample preparation. Various compositions and functionalizations extended the applications of nanomaterials in sample preparations, and distinct size and shape selectivity was generated from the diversified pore structures of nanoporous materials. Such great variety make nanomaterials a kind of versatile tools in sample preparation for almost all categories of analytes. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Semiquantitative Performance and Mechanism Evaluation of Carbon Nanomaterials as Cathode Coatings for Microbial Fouling Reduction

    PubMed Central

    Zhang, Qiaoying; Nghiem, Joanne; Silverberg, Gregory J.

    2015-01-01

    In this study, we examine bacterial attachment and survival on a titanium (Ti) cathode coated with various carbon nanomaterials (CNM): pristine carbon nanotubes (CNT), oxidized carbon nanotubes (O-CNT), oxidized-annealed carbon nanotubes (OA-CNT), carbon black (CB), and reduced graphene oxide (rGO). The carbon nanomaterials were dispersed in an isopropyl alcohol-Nafion solution and were then used to dip-coat a Ti substrate. Pseudomonas fluorescens was selected as the representative bacterium for environmental biofouling. Experiments in the absence of an electric potential indicate that increased nanoscale surface roughness and decreased hydrophobicity of the CNM coating decreased bacterial adhesion. The loss of bacterial viability on the noncharged CNM coatings ranged from 22% for CB to 67% for OA-CNT and was dependent on the CNM dimensions and surface chemistry. For electrochemical experiments, the total density and percentage of inactivation of the adherent bacteria were analyzed semiquantitatively as functions of electrode potential, current density, and hydrogen peroxide generation. Electrode potential and hydrogen peroxide generation were the dominant factors with regard to short-term (3-h) bacterial attachment and inactivation, respectively. Extended-time electrochemical experiments (12 h) indicated that in all cases, the density of total deposited bacteria increased almost linearly with time and that the rate of bacterial adhesion was decreased 8- to 10-fold when an electric potential was applied. In summary, this study provides a fundamental rationale for the selection of CNM as cathode coatings and electric potential to reduce microbial fouling. PMID:25956770

  9. SnO₂-based nanomaterials: synthesis and application in lithium-ion batteries.

    PubMed

    Chen, Jun Song; Lou, Xiong Wen David

    2013-06-10

    The development of new electrode materials for lithium-ion batteries (LIBs) has always been a focal area of materials science, as the current technology may not be able to meet the high energy demands for electronic devices with better performance. Among all the metal oxides, tin dioxide (SnO₂) is regarded as a promising candidate to serve as the anode material for LIBs due to its high theoretical capacity. Here, a thorough survey is provided of the synthesis of SnO₂-based nanomaterials with various structures and chemical compositions, and their application as negative electrodes for LIBs. It covers SnO₂ with different morphologies ranging from 1D nanorods/nanowires/nanotubes, to 2D nanosheets, to 3D hollow nanostructures. Nanocomposites consisting of SnO₂ and different carbonaceous supports, e.g., amorphous carbon, carbon nanotubes, graphene, are also investigated. The use of Sn-based nanomaterials as the anode material for LIBs will be briefly discussed as well. The aim of this review is to provide an in-depth and rational understanding such that the electrochemical properties of SnO₂-based anodes can be effectively enhanced by making proper nanostructures with optimized chemical composition. By focusing on SnO₂, the hope is that such concepts and strategies can be extended to other potential metal oxides, such as titanium dioxide or iron oxides, thus shedding some light on the future development of high-performance metal-oxide based negative electrodes for LIBs.

  10. Graphene in turbine blades

    NASA Astrophysics Data System (ADS)

    Das, D. K.; Swain, P. K.; Sahoo, S.

    2016-07-01

    Graphene, the two-dimensional (2D) nanomaterial, draws interest of several researchers due to its many superior properties. It has extensive applications in numerous fields. A turbine is a hydraulic machine which extracts energy from a fluid and converts it into useful work. Recently, Gudukeya and Madanhire have tried to increase the efficiency of Pelton turbine. Beucher et al. have also tried the same by reducing friction between fluid and turbine blades. In this paper, we study the advantages of using graphene as a coating on Pelton turbine blades. It is found that the efficiency of turbines increases, running and maintenance cost is reduced with more power output. By the application of graphene in pipes, cavitation will be reduced, durability of pipes will increase, operation and maintenance cost of water power plants will be less.

  11. Nanomaterials for biosensing applications: A Review

    NASA Astrophysics Data System (ADS)

    Holzinger, Michael; Le Goff, Alan; Cosnier, Serge

    2014-08-01

    A biosensor device is defined by its biological, or bioinspired receptor unit with unique specificities towards corresponding analytes. These analytes are often of biological origin like DNAs or proteins from the immune system (antibodies, antigens) of diseases or infections. Such analytes can also be simple molecules like glucose or pollutants when a biological receptor unit with particular specificity is available. One of many other challenges in biosensor development is the efficient signal capture of the biological recognition event (transduction). Such transducers translate the interaction of the analyte with the biological element into electrochemical, electrochemiluminescent, magnetic, gravimetric, or optical signals. In order to increase sensitivities and to lower detection limits down to even individual molecules, nanomaterials are promising candidates due to the possibility to immobilize an enhanced quantity of bioreceptor units at reduced volumes and even to act itself as transduction element. Among such nanomaterials, gold nanoparticles, semi-conductor quantum dots, polymer nanoparticles, carbon nanotubes, nanodiamonds, and graphene are intensively studied. Due to the vast evolution of this research field, this review summarizes in a non-exhaustive way the advantages of nanomaterials by focusing on nano-objects which provide further beneficial properties than “just” an enhanced surface area.

  12. Nanomaterials from Nanocomponents: Synthesis and Properties of Hybrid Nanomaterials

    NASA Astrophysics Data System (ADS)

    Akey, Austin Joseph

    This thesis consists of two series of investigations into two different classes of hybrid nanomaterials, their formation and properties. In the first part of this thesis, hybrid nanomaterials composed of cadmium selenide nanoparticles and single-walled carbon nanotubes (SWNTs) are discussed; a novel synthetic method for these hybrids is presented, and an anomalous photoluminescence behavior is examined. Our experiments show that SWNTs can be decorated with CdSe nanoparticles at high loading densities, following the removal of the nanoparticle surface ligands and replacement with pyridine. The resulting hybrids are thermally stable up to 350°C and mechanically stable against sonication. The photoluminescence Stokes shift in the bound nanoparticles is shown to be reduced relative to that of unbound nanoparticles. This difference is attributed to Forster resonance energy transfer from the nanoparticles to the nanotube, leading to hot luminescence in the nanoparticles. The second part of this thesis focuses on formation strategies and mechanisms for nanoparticle superlattices. Supercrystals, as they are called, are formed using lithographically-patterned reservoirs and capillary channels, giving control over both supercrystal dimensions and placement; these supercrystals form within a few hours, much faster than those previously reported. These results are extended to the formation of large-area (> 10 mum lateral dimension) thick (> 1 mum) supercrystals on substrates, and the formation mechanism probed by in situ small-angle x-ray scattering. Both monocomponent and binary supercrystals are examined.

  13. Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

    NASA Astrophysics Data System (ADS)

    Yao, Shanshan; Zhu, Yong

    2016-04-01

    Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

  14. Green Processing of Carbon Nanomaterials.

    PubMed

    Kawamoto, Masuki; He, Pan; Ito, Yoshihiro

    2017-07-01

    Carbon nanomaterials (CNMs) from fullerenes, carbon nanotubes, and graphene are promising carbon allotropes for various applications such as energy-conversion devices and biosensors. Because pristine CNMs show substantial van der Waals interactions and a hydrophobic nature, precipitation is observed immediately in most organic solvents and water. This inevitable aggregation leads to poor processability and diminishes the intrinsic properties of the CNMs. Highly toxic and hazardous chemicals are used for chemical and physical modification of CNMs, even though efficient dispersed solutions are obtained. The development of an environmentally friendly dispersion method for both safe and practical processing is a great challenge. Recent green processing approaches for the manipulation of CNMs using chemical and physical modification are highlighted. A summary of the current research progress on: i) energy-efficient and less-toxic chemical modification of CNMs using covalent-bonding functionality and ii) non-covalent-bonding methodologies through physical modification using green solvents and dispersants, and chemical-free mechanical stimuli is provided. Based on these experimental studies, recent advances and challenges for the potential application of green-processable energy-conversion and biological devices are provided. Finally, a conclusion section is provided summarizing the insights from the present studies as well as some future perspectives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Graphene and graphene-like 2D materials for optical biosensing and bioimaging: a review

    NASA Astrophysics Data System (ADS)

    Zhu, Chengzhou; Du, Dan; Lin, Yuehe

    2015-09-01

    The increasing demands of bioassay and biomedical applications have significantly promoted the rational design and fabrication of a wide range of functional nanomaterials. Coupling these advanced nanomaterials with biomolecule recognition events leads to novel sensing and diagnostic platforms. Because of their unique structures and multifunctionalities, two-dimensional nanomaterials, such as graphene and graphene-like materials (e.g., graphitic carbon nitride, transition metal dichalcogenides, boron nitride, and transition metal oxides), have stimulated great interest in the field of optical biosensors and imaging because of their innovative mechanical, physicochemical and optical properties. Depending on the different applications, the graphene and graphene-like nanomaterials can be tailored to form either fluorescent emitters or efficient fluorescence quenchers, making them powerful platforms for fabricating a series of optical biosensors to sensitively detect various targets including ions, small biomolecules, DNA/RNA and proteins. This review highlights the recent progress in optical biosensors based on graphene and graphene-like 2D materials and their imaging applications. Finally, the opportunities and some critical challenges in this field are also addressed.

  16. Recent trends in carbon nanomaterial-based electrochemical sensors for biomolecules: A review.

    PubMed

    Yang, Cheng; Denno, Madelaine E; Pyakurel, Poojan; Venton, B Jill

    2015-08-05

    Carbon nanomaterials are advantageous for electrochemical sensors because they increase the electroactive surface area, enhance electron transfer, and promote adsorption of molecules. Carbon nanotubes (CNTs) have been incorporated into electrochemical sensors for biomolecules and strategies have included the traditional dip coating and drop casting methods, direct growth of CNTs on electrodes and the use of CNT fibers and yarns made exclusively of CNTs. Recent research has also focused on utilizing many new types of carbon nanomaterials beyond CNTs. Forms of graphene are now increasingly popular for sensors including reduced graphene oxide, carbon nanohorns, graphene nanofoams, graphene nanorods, and graphene nanoflowers. In this review, we compare different carbon nanomaterial strategies for creating electrochemical sensors for biomolecules. Analytes covered include neurotransmitters and neurochemicals, such as dopamine, ascorbic acid, and serotonin; hydrogen peroxide; proteins, such as biomarkers; and DNA. The review also addresses enzyme-based electrodes that are used to detect non-electroactive species such as glucose, alcohols, and proteins. Finally, we analyze some of the future directions for the field, pointing out gaps in fundamental understanding of electron transfer to carbon nanomaterials and the need for more practical implementation of sensors.

  17. Recent trends in carbon nanomaterial-based electrochemical sensors for biomolecules: A review

    PubMed Central

    Yang, Cheng; Denno, Madelaine E.; Pyakurel, Poojan; Venton, B. Jill

    2015-01-01

    Carbon nanomaterials are advantageous for electrochemical sensors because they increase the electroactive surface area, enhance electron transfer, and promote adsorption of molecules. Carbon nanotubes (CNTs) have been incorporated into electrochemical sensors for biomolecules and strategies have included the traditional dip coating and drop casting methods, direct growth of CNTs on electrodes and the use of CNT fibers and yarns made exclusively of CNTs. Recent research has also focused on utilizing many new types of carbon nanomaterials beyond CNTs. Forms of graphene are now increasingly popular for sensors including reduced graphene oxide, carbon nanohorns, graphene nanofoams, graphene nanorods, and graphene nanoflowers. In this review, we compare different carbon nanomaterial strategies for creating electrochemical sensors for biomolecules. Analytes covered include neurotransmitters and neurochemicals, such as dopamine, ascorbic acid, and serotonin; hydrogen peroxide; proteins, such as biomarkers; and DNA. The review also addresses enzyme-based electrodes that are used to detect non-electroactive species such as glucose, alcohols, and proteins. Finally, we analyze some of the future directions for the field, pointing out gaps in fundamental understanding of electron transfer to carbon nanomaterials and the need for more practical implementation of sensors. PMID:26320782

  18. Recent applications of carbon-based nanomaterials in analytical chemistry: critical review.

    PubMed

    Scida, Karen; Stege, Patricia W; Haby, Gabrielle; Messina, Germán A; García, Carlos D

    2011-04-08

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005-2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry.

  19. Recent Applications of Carbon-Based Nanomaterials in Analytical Chemistry: Critical Review

    PubMed Central

    Scida, Karen; Stege, Patricia W.; Haby, Gabrielle; Messina, Germán A.; García, Carlos D.

    2011-01-01

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005–2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry. PMID:21458626

  20. Measurement of Transport Properties of Aerosolized Nanomaterials

    PubMed Central

    Ku, Bon Ki; Kulkarni, Pramod

    2015-01-01

    Airborne engineered nanomaterials such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), functionalized MWCNT, graphene, fullerene, silver and gold nanorods were characterized using a tandem system of a differential mobility analyzer and an aerosol particle mass analyzer to obtain their airborne transport properties and understand their relationship to morphological characteristics. These nanomaterials were aerosolized using different generation methods such as electrospray, pneumatic atomization, and dry aerosolization techniques, and their airborne transport properties such as mobility and aerodynamic diameters, mass scaling exponent, dynamic shape factor, and effective density were obtained. Laboratory experiments were conducted to directly measure mobility diameter and mass of the airborne nanomaterials using tandem mobility-mass measurements. Mass scaling exponents, aerodynamic diameters, dynamic shape factors and effective densities of mobility-classified particles were obtained from particle mass and the mobility diameter. Microscopy analysis using Transmission Electron Microscopy (TEM) was performed to obtain morphological descriptors such as envelop diameter, open area, aspect ratio, and projected area diameter. The morphological information from the TEM was compared with measured aerodynamic and mobility diameters of the particles. The results showed that aerodynamic diameter is smaller than mobility diameter below 500 nm by a factor of 2 to 4 for all nanomaterials except silver and gold nanorods. Morphologies of MWCNTs generated by liquid-based method, such as pneumatic atomization, are more compact than those of dry dispersed MWCNTs, indicating that the morphology depends on particle generation method. TEM analysis showed that projected area diameter of MWCNTs appears to be in reasonable agreement with mobility diameter in the size range from 100 – 400 nm. Principal component analysis of the obtained airborne particle

  1. Measurement of Transport Properties of Aerosolized Nanomaterials.

    PubMed

    Ku, Bon Ki; Kulkarni, Pramod

    2015-12-01

    Airborne engineered nanomaterials such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), functionalized MWCNT, graphene, fullerene, silver and gold nanorods were characterized using a tandem system of a differential mobility analyzer and an aerosol particle mass analyzer to obtain their airborne transport properties and understand their relationship to morphological characteristics. These nanomaterials were aerosolized using different generation methods such as electrospray, pneumatic atomization, and dry aerosolization techniques, and their airborne transport properties such as mobility and aerodynamic diameters, mass scaling exponent, dynamic shape factor, and effective density were obtained. Laboratory experiments were conducted to directly measure mobility diameter and mass of the airborne nanomaterials using tandem mobility-mass measurements. Mass scaling exponents, aerodynamic diameters, dynamic shape factors and effective densities of mobility-classified particles were obtained from particle mass and the mobility diameter. Microscopy analysis using Transmission Electron Microscopy (TEM) was performed to obtain morphological descriptors such as envelop diameter, open area, aspect ratio, and projected area diameter. The morphological information from the TEM was compared with measured aerodynamic and mobility diameters of the particles. The results showed that aerodynamic diameter is smaller than mobility diameter below 500 nm by a factor of 2 to 4 for all nanomaterials except silver and gold nanorods. Morphologies of MWCNTs generated by liquid-based method, such as pneumatic atomization, are more compact than those of dry dispersed MWCNTs, indicating that the morphology depends on particle generation method. TEM analysis showed that projected area diameter of MWCNTs appears to be in reasonable agreement with mobility diameter in the size range from 100 - 400 nm. Principal component analysis of the obtained airborne particle

  2. The interplay between carbon nanomaterials and amyloid fibrils in bio-nanotechnology.

    PubMed

    Li, Chaoxu; Mezzenga, Raffaele

    2013-07-21

    Recent advances in bio-nanotechnology have not only rapidly broadened the applications and scope of hybrid nanomaterials in biological fields, but also greatly enriched the examples of ordered materials based on supramolecular self-assembly. Among eminent examples of functional nanostructured materials of undisputed impact in nanotechnology and biological environments, carbon nanomaterials (such as fullerenes, carbon nanotubes and graphene) and amyloid fibrils have attracted great attention because of their unique architectures and exceptional physical properties. Nonetheless, combination of these two classes of nanomaterials into functional hybrids is far from trivial. For example, the presence of carbon nanomaterials can offer either an inhibitory effect or promotion of amyloid fibrillation, depending on the structural architectures of carbon nanomaterials and the starting amyloid proteins/peptides considered. To date, numerous studies have been devoted to evaluating both the biological toxicity of carbon nanomaterials and their use in developing therapies for amyloidosis. At the same time, hybridization of these two classes of nanomaterials offers new possibilities for combining some of their desirable properties into nanocomposites of possible use in electronics, actuators, sensing, biomedicine and structural materials. This review describes recent developments in the hybridization of carbon nanomaterials and amyloid fibrils and discusses the current state of the art on the application of carbon nanomaterial-amyloid fibril hybrids in bio-nanotechnology.

  3. The interplay between carbon nanomaterials and amyloid fibrils in bio-nanotechnology

    NASA Astrophysics Data System (ADS)

    Li, Chaoxu; Mezzenga, Raffaele

    2013-06-01

    Recent advances in bio-nanotechnology have not only rapidly broadened the applications and scope of hybrid nanomaterials in biological fields, but also greatly enriched the examples of ordered materials based on supramolecular self-assembly. Among eminent examples of functional nanostructured materials of undisputed impact in nanotechnology and biological environments, carbon nanomaterials (such as fullerenes, carbon nanotubes and graphene) and amyloid fibrils have attracted great attention because of their unique architectures and exceptional physical properties. Nonetheless, combination of these two classes of nanomaterials into functional hybrids is far from trivial. For example, the presence of carbon nanomaterials can offer either an inhibitory effect or promotion of amyloid fibrillation, depending on the structural architectures of carbon nanomaterials and the starting amyloid proteins/peptides considered. To date, numerous studies have been devoted to evaluating both the biological toxicity of carbon nanomaterials and their use in developing therapies for amyloidosis. At the same time, hybridization of these two classes of nanomaterials offers new possibilities for combining some of their desirable properties into nanocomposites of possible use in electronics, actuators, sensing, biomedicine and structural materials. This review describes recent developments in the hybridization of carbon nanomaterials and amyloid fibrils and discusses the current state of the art on the application of carbon nanomaterial-amyloid fibril hybrids in bio-nanotechnology.

  4. Nanomaterial-based biosensors using dual transducing elements for solution phase detection.

    PubMed

    Li, Ning; Su, Xiaodi; Lu, Yi

    2015-05-07

    Biosensors incorporating nanomaterials have demonstrated superior performance compared to their conventional counterparts. Most reported sensors use nanomaterials as a single transducer of signals, while biosensor designs using dual transducing elements have emerged as new approaches to further improve overall sensing performance. This review focuses on recent developments in nanomaterial-based biosensors using dual transducing elements for solution phase detection. The review begins with a brief introduction of the commonly used nanomaterial transducers suitable for designing dual element sensors, including quantum dots, metal nanoparticles, upconversion nanoparticles, graphene, graphene oxide, carbon nanotubes, and carbon nanodots. This is followed by the presentation of the four basic design principles, namely Förster Resonance Energy Transfer (FRET), Amplified Fluorescence Polarization (AFP), Bio-barcode Assay (BCA) and Chemiluminescence (CL), involving either two kinds of nanomaterials, or one nanomaterial and an organic luminescent agent (e.g. organic dyes, luminescent polymers) as dual transducers. Biomolecular and chemical analytes or biological interactions are detected by their control of the assembly and disassembly of the two transducing elements that change the distance between them, the size of the fluorophore-containing composite, or the catalytic properties of the nanomaterial transducers, among other property changes. Comparative discussions on their respective design rules and overall performances are presented afterwards. Compared with the single transducer biosensor design, such a dual-transducer configuration exhibits much enhanced flexibility and design versatility, allowing biosensors to be more specifically devised for various purposes. The review ends by highlighting some of the further development opportunities in this field.

  5. Promising applications of graphene and graphene-based nanostructures

    NASA Astrophysics Data System (ADS)

    Nguyen, Bich Ha; Hieu Nguyen, Van

    2016-06-01

    densities; fabrication of anodes for lithium ion batteries from crumpled graphene-encapsulated Si nanoparticles; liquid-mediated dense integration of graphene materials for compact capacitive energy storage; scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage; superior micro-supercapacitors based on graphene quantum dots; all-graphene core-sheat microfibres for all-solid-state, stretchable fibriform supercapacitors and wearable electronic textiles; micro-supercapacitors with high electrochemical performance based on three-dimensional graphene-carbon nanotube carpets; macroscopic nitrogen-doped graphene hydrogels for ultrafast capacitors; manufacture of scalable ultra-thin and high power density graphene electrochemical capacitor electrodes by aqueous exfoliation and spray deposition; scalable synthesis of hierarchically structured carbon nanotube-graphene fibers for capacitive energy storage; phosphorene-graphene hybrid material as a high-capacity anode material for sodium-ion batteries. Beside above-presented promising applications of graphene and graphene-based nanostructures, other less widespread, but perhaps not less important, applications of graphene and graphene-based nanomaterials, are also briefly discussed.

  6. Nanomaterials and bone regeneration

    PubMed Central

    Gong, Tao; Xie, Jing; Liao, Jinfeng; Zhang, Tao; Lin, Shiyu; Lin, Yunfeng

    2015-01-01

    The worldwide incidence of bone disorders and conditions has been increasing. Bone is a nanomaterials composed of organic (mainly collagen) and inorganic (mainly nano-hydroxyapatite) components, with a hierarchical structure ranging from nanoscale to macroscale. In consideration of the serious limitation in traditional therapies, nanomaterials provide some new strategy in bone regeneration. Nanostructured scaffolds provide a closer structural support approximation to native bone architecture for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. In this article, we focused on reviewing the classification and design of nanostructured materials and nanocarrier materials for bone regeneration, their cell interaction properties, and their application in bone tissue engineering and regeneration. Furthermore, some new challenges about the future research on the application of nanomaterials for bone regeneration are described in the conclusion and perspectives part. PMID:26558141

  7. DNA-decorated graphene chemical sensors

    NASA Astrophysics Data System (ADS)

    Goldsmith, Brett; Lu, Ye; Kybert, Nicholas; Johnson, A. T. Charlie

    2010-03-01

    We measure the sensing response of DNA functionalized graphene to various analytes. Graphene is the current flagship nanomaterial and has been actively studied as a chemical sensor since shortly after it was isolated. Increasingly sophisticated device processing has revealed that some early measurements of graphene chemical sensing have been amplified by unintentional functionalization. We start with chemically clean graphene transistors and purposefully functionalize them to allow chemical sensing responses not found using pristine graphene. By using different DNA sequences during our functionalization, we are able to change the chemical sensitivity of the graphene. The resulting devices show fast response times, complete recovery at room temperature and discrimination between several similar analytes. This work has been supported by the IC Postdoc program, REU and the Nano/Bio Interface Center.

  8. Graphene-based materials for tissue engineering.

    PubMed

    Shin, Su Ryon; Li, Yi-Chen; Jang, Hae Lin; Khoshakhlagh, Parastoo; Akbari, Mohsen; Nasajpour, Amir; Zhang, Yu Shrike; Tamayol, Ali; Khademhosseini, Ali

    2016-10-01

    Graphene and its chemical derivatives have been a pivotal new class of nanomaterials and a model system for quantum behavior. The material's excellent electrical conductivity, biocompatibility, surface area and thermal properties are of much interest to the scientific community. Two-dimensional graphene materials have been widely used in various biomedical research areas such as bioelectronics, imaging, drug delivery, and tissue engineering. In this review, we will highlight the recent applications of graphene-based materials in tissue engineering and regenerative medicine. In particular, we will discuss the application of graphene-based materials in cardiac, neural, bone, cartilage, skeletal muscle, and skin/adipose tissue engineering. We will also discuss the potential risk factors of graphene-based materials in tissue engineering. In conclusion, we will outline the opportunities in the usage of graphene-based materials for clinical applications. Published by Elsevier B.V.

  9. Functional DNA Nanomaterials

    NASA Astrophysics Data System (ADS)

    Zhao, Zhao

    The discovery of DNA helical structure opened the door of modern molecular biology. Ned Seeman utilized DNA as building block to construct different nanoscale materials, and introduced a new field, know as DNA nanotechnology. After several decades of development, different DNA structures had been created, with different dimension, different morphology and even with complex curvatures. In addition, after construction of enough amounts DNA structure candidates, DNA structure template, with excellent spatial addressability, had been used to direct the assembly of different nanomaterials, including nanoparticles and proteins, to produce different functional nanomaterials. However there are still many challenges to fabricate functional DNA nanostructures. The first difficulty is that the present finite sized template dimension is still very small, usually smaller than 100nm, which will limit the application for large amount of nanomaterials assembly or large sized nanomaterials assembly. Here we tried to solve this problem through developing a new method, superorigami, to construct finite sized DNA structure with much larger dimension, which can be as large as 500nm. The second problem will be explored the ability of DNA structure to assemble inorganic nanomaterials for novel photonic or electronic properties. Here we tried to utilize DNA Origami method to assemble AuNPs with controlled 3D spacial position for possible chiral photonic complex. We also tried to assemble SWNT with discrete length for possible field effect transistor device. In addition, we tried to mimic in vivo compartment with DNA structure to study internalized enzyme behavior. From our results, constructed DNA cage origami can protect encapsulated enzyme from degradation, and internalized enzyme activity can be boosted for up to 10 folds. In summary, DNA structure can serve as an ideal template for construction of functional nanomaterials with lots of possibilities to be explored.

  10. Biological and Pharmaceutical Nanomaterials

    NASA Astrophysics Data System (ADS)

    Kumar, Challa S. S. R.

    2006-01-01

    This first comprehensive yet concise overview of all important classes of biological and pharmaceutical nanomaterials presents in one volume the different kinds of natural biological compounds that form nanomaterials or that may be used to purposefully create them. This unique single source of information brings together the many articles published in specialized journals, which often remain unseen by members of other, related disciplines. Covering pharmaceutical, nucleic acid, peptide and DNA-Chitosan nanoparticles, the book focuses on those innovative materials and technologies needed for the continued growth of medicine, healthcare, pharmaceuticals and human wellness. For chemists, biochemists, cell biologists, materials scientists, biologists, and those working in the pharmaceutical and chemical industries.

  11. Nanomaterials for Defense Applications

    NASA Astrophysics Data System (ADS)

    Turaga, Uday; Singh, Vinitkumar; Lalagiri, Muralidhar; Kiekens, Paul; Ramkumar, Seshadri S.

    Nanotechnology has found a number of applications in electronics and healthcare. Within the textile field, applications of nanotechnology have been limited to filters, protective liners for chemical and biological clothing and nanocoatings. This chapter presents an overview of the applications of nanomaterials such as nanofibers and nanoparticles that are of use to military and industrial sectors. An effort has been made to categorize nanofibers based on the method of production. This chapter particularly focuses on a few latest developments that have taken place with regard to the application of nanomaterials such as metal oxides in the defense arena.

  12. Fluorescent biosensors enabled by graphene and graphene oxide.

    PubMed

    Zhang, Huan; Zhang, Honglu; Aldalbahi, Ali; Zuo, Xiaolei; Fan, Chunhai; Mi, Xianqiang

    2017-03-15

    During the past few years, graphene and graphene oxide (GO) have attracted numerous attentions for the potential applications in various fields from energy technology, biosensing to biomedical diagnosis and therapy due to their various functionalization, high volume surface ratio, unique physical and electrical properties. Among which, graphene and graphene oxide based fluorescent biosensors enabled by their fluorescence-quenching properties have attracted great interests. The fluorescence of fluorophore or dye labeled on probes (such as molecular beacon, aptamer, DNAzymes and so on) was quenched after adsorbed on to the surface of graphene. While in the present of the targets, due to the strong interactions between probes and targets, the probes were detached from the surface of graphene, generating dramatic fluorescence, which could be used as signals for detection of the targets. This strategy was simple and economy, together with great programmable abilities of probes; we could realize detection of different kinds of species. In this review, we first briefly introduced the history of graphene and graphene oxide, and then summarized the fluorescent biosensors enabled by graphene and GO, with a detailed account of the design mechanism and comparison with other nanomaterials (e.g. carbon nanotubes and gold nanoparticles). Following that, different sensing platforms for detection of DNAs, ions, biomolecules and pathogens or cells as well as the cytotoxicity issue of graphene and GO based in vivo biosensing were further discussed. We hope that this review would do some help to researchers who are interested in graphene related biosening research work. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Intracellular Signal Modulation by Nanomaterials

    PubMed Central

    Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

    2016-01-01

    A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive Oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can crucially affect the cytotoxicity of nanomaterials and membrane-dependent signaling pathways can be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future. PMID:24683030

  14. Intracellular signal modulation by nanomaterials.

    PubMed

    Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

    2014-01-01

    A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can be of crucial importance for the cytotoxicity of nanomaterials and membrane-dependent signaling pathways have also been shown to be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials, effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future.

  15. Graphene: a versatile nanoplatform for biomedical applications

    PubMed Central

    Zhang, Yin; Nayak, Tapas R.; Hong, Hao; Cai, Weibo

    2012-01-01

    Graphene, with its excellent physical, chemical, and mechanical properties, holds tremendous potential for a wide variety of biomedical applications. As research on graphene-based nanomaterials is still at a nascent stage, due to the very short time span since its initial report in 2004, a focused review on this topic is timely and necessary. In this feature review, we first summarize the results from toxicity studies of graphene and its derivatives. Although literature reports have mixed findings, we emphasize that the key question is not how toxic graphene itself is, but how to modify and functionalize it and its derivatives so that they do not exhibit acute/chronic toxicity, can be cleared from the body over time, and thereby can be best used for biomedical applications. Next, we discuss in detail the exploration of graphene-based nanomaterials for tissue engineering, molecular imaging, and drug/gene delivery applications. The future of graphene-based nanomaterials in biomedicine looks brighter than ever, and it is expected that they will find a wide range of biomedical applications with future research effort and interdisciplinary collaboration. PMID:22653227

  16. Advanced Nanomaterials for High-Efficiency Solar Cells

    SciTech Connect

    Chen, Junhong

    2013-11-29

    Energy supply has arguably become one of the most important problems facing humankind. The exponential demand for energy is evidenced by dwindling fossil fuel supplies and record-high oil and gas prices due to global population growth and economic development. This energy shortage has significant implications to the future of our society, in addition to the greenhouse gas emission burden due to consumption of fossil fuels. Solar energy seems to be the most viable choice to meet our clean energy demand given its large scale and clean/renewable nature. However, existing methods to convert sun light into electricity are not efficient enough to become a practical alternative to fossil fuels. This DOE project aims to develop advanced hybrid nanomaterials consisting of semiconductor nanoparticles (quantum dots or QDs) supported on graphene for cost-effective solar cells with improved conversion efficiency for harvesting abundant, renewable, clean solar energy to relieve our global energy challenge. Expected outcomes of the project include new methods for low-cost manufacturing of hybrid nanostructures, systematic understanding of their properties that can be tailored for desired applications, and novel photovoltaic cells. Through this project, we have successfully synthesized a number of novel nanomaterials, including vertically-oriented graphene (VG) sheets, three-dimensional (3D) carbon nanostructures comprising few-layer graphene (FLG) sheets inherently connected with CNTs through sp{sup 2} carbons, crumpled graphene (CG)-nanocrystal hybrids, CdSe nanoparticles (NPs), CdS NPs, nanohybrids of metal nitride decorated on nitrogen-doped graphene (NG), QD-carbon nanotube (CNT) and QD-VG-CNT structures, TiO{sub 2}-CdS NPs, and reduced graphene oxide (RGO)-SnO{sub 2} NPs. We further assembled CdSe NPs onto graphene sheets and investigated physical and electronic interactions between CdSe NPs and the graphene. Finally we have demonstrated various applications of these

  17. Deformable devices with integrated functional nanomaterials for wearable electronics

    NASA Astrophysics Data System (ADS)

    Kim, Jaemin; Lee, Jongsu; Son, Donghee; Choi, Moon Kee; Kim, Dae-Hyeong

    2016-03-01

    As the market and related industry for wearable electronics dramatically expands, there are continuous and strong demands for flexible and stretchable devices to be seamlessly integrated with soft and curvilinear human skin or clothes. However, the mechanical mismatch between the rigid conventional electronics and the soft human body causes many problems. Therefore, various prospective nanomaterials that possess a much lower flexural rigidity than their bulk counterparts have rapidly established themselves as promising electronic materials replacing rigid silicon and/or compound semiconductors in next-generation wearable devices. Many hybrid structures of multiple nanomaterials have been also developed to pursue both high performance and multifunctionality. Here, we provide an overview of state-of-the-art wearable devices based on one- or two-dimensional nanomaterials (e.g., carbon nanotubes, graphene, single-crystal silicon and oxide nanomembranes, organic nanomaterials and their hybrids) in combination with zero-dimensional functional nanomaterials (e.g., metal/oxide nanoparticles and quantum dots). Starting from an introduction of materials strategies, we describe device designs and the roles of individual ones in integrated systems. Detailed application examples of wearable sensors/actuators, memories, energy devices, and displays are also presented.

  18. Deformable devices with integrated functional nanomaterials for wearable electronics.

    PubMed

    Kim, Jaemin; Lee, Jongsu; Son, Donghee; Choi, Moon Kee; Kim, Dae-Hyeong

    2016-01-01

    As the market and related industry for wearable electronics dramatically expands, there are continuous and strong demands for flexible and stretchable devices to be seamlessly integrated with soft and curvilinear human skin or clothes. However, the mechanical mismatch between the rigid conventional electronics and the soft human body causes many problems. Therefore, various prospective nanomaterials that possess a much lower flexural rigidity than their bulk counterparts have rapidly established themselves as promising electronic materials replacing rigid silicon and/or compound semiconductors in next-generation wearable devices. Many hybrid structures of multiple nanomaterials have been also developed to pursue both high performance and multifunctionality. Here, we provide an overview of state-of-the-art wearable devices based on one- or two-dimensional nanomaterials (e.g., carbon nanotubes, graphene, single-crystal silicon and oxide nanomembranes, organic nanomaterials and their hybrids) in combination with zero-dimensional functional nanomaterials (e.g., metal/oxide nanoparticles and quantum dots). Starting from an introduction of materials strategies, we describe device designs and the roles of individual ones in integrated systems. Detailed application examples of wearable sensors/actuators, memories, energy devices, and displays are also presented.

  19. DNA-incorporating nanomaterials in biotechnological applications

    SciTech Connect

    Stadler, A.; van der Lelie, D.; Chi, C.; Gang, O.

    2010-02-01

    The recently developed ability to controllably connect biological and inorganic objects on a molecular scale opens a new page in biomimetic methods with potential applications in biodetection, tissue engineering, targeted therapeutics and drug/gene delivery. Particularly in the biodetection arena, a rapid development of new platforms has largely been stimulated by a spectrum of novel nanomaterials with physical properties that offer efficient, sensitive and inexpensive molecular sensing. Recently, DNA-functionalized nano-objects have emerged as a new class of nanomaterials that can be controllably assembled in predesigned structures. Such DNA-based nanoscale structures might provide a new detection paradigm due to their regulated optical, electrical and magnetic responses, chemical heterogeneity and high local biomolecular concentration. The specific biorecognition DNA and its physical-chemical characteristics allows for an exploitation of DNA-functionalized nanomaterials for sensing of nucleic acids, while a broad tunability of DNA interactions permits extending their use for detection of proteins, small molecules and ions. We discuss the progress that was achieved in the last decade in the exploration of new detection methods based on DNA-incorporating nanomaterials as well as their applications to gene delivery. The comparison between various detection platforms, their sensitivity and selectivity, and specific applications are reviewed.

  20. Growing Carbon Nanotubes from Both Sides of Graphene.

    PubMed

    Jiang, Jinlong; Li, Yilun; Gao, Caitian; Kim, Nam Dong; Fan, Xiujun; Wang, Gunuk; Peng, Zhiwei; Hauge, Robert H; Tour, James M

    2016-03-23

    The design and synthesis of hybrid structures between graphene and carbon nanotubes is an intriguing topic in the field of carbon nanomaterials. Here the synthesis of vertically aligned CNT carpets underneath graphene and from both sides of graphene is described with continuous ordering over a large area. Scanning electron microscopy and Raman spectroscopic characterizations show that CNT carpets grow underneath graphene through a base-growth mechanism, and grow on top of graphene through a tip-growth mechanism. Good electrical contact is observed from the top CNT carpets, through the graphene layer, to the bottom CNT carpets. This sandwich-like CNT/graphene/CNT hybrid structure could provide an approach to design and fabricate multilayered graphene/CNTs materials, as well as potential applications in the fields of nanomanufacturing and energy storage.

  1. Graphene-Based Materials for Biosensors: A Review.

    PubMed

    Suvarnaphaet, Phitsini; Pechprasarn, Suejit

    2017-09-21

    The advantages conferred by the physical, optical and electrochemical properties of graphene-based nanomaterials have contributed to the current variety of ultrasensitive and selective biosensor devices. In this review, we present the points of view on the intrinsic properties of graphene and its surface engineering concerned with the transduction mechanisms in biosensing applications. We explain practical synthesis techniques along with prospective properties of the graphene-based materials, which include the pristine graphene and functionalized graphene (i.e., graphene oxide (GO), reduced graphene oxide (RGO) and graphene quantum dot (GQD). The biosensing mechanisms based on the utilization of the charge interactions with biomolecules and/or nanoparticle interactions and sensing platforms are also discussed, and the importance of surface functionalization in recent up-to-date biosensors for biological and medical applications.

  2. Toxicity of nanomaterials

    PubMed Central

    Sharifi, Shahriar; Behzadi, Shahed; Laurent, Sophie; Forrest, M. Laird; Stroeve, Pieter

    2015-01-01

    Nanoscience has matured significantly during the last decade as it has transitioned from bench top science to applied technology. Presently, nanomaterials are used in a wide variety of commercial products such as electronic components, sports equipment, sun creams and biomedical applications. There are few studies of the long-term consequences of nanoparticles on human health, but governmental agencies, including the United States National Institute for Occupational Safety and Health and Japan’s Ministry of Health, have recently raised the question of whether seemingly innocuous materials such as carbon-based nanotubes should be treated with the same caution afforded known carcinogens such as asbestos. Since nanomaterials are increasing a part of everyday consumer products, manufacturing processes, and medical products, it is imperative that both workers and end-users be protected from inhalation of potentially toxic NPs. It also suggests that NPs may need to be sequestered into products so that the NPs are not released into the atmosphere during the product’s life or during recycling. Further, non-inhalation routes of NP absorption, including dermal and medical injectables, must be studied in order to understand possible toxic effects. Fewer studies to date have addressed whether the body can eventually eliminate nanomaterials to prevent particle build-up in tissues or organs. This critical review discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity. PMID:22170510

  3. Nanomaterial disposal by incineration

    EPA Science Inventory

    As nanotechnology-based products enter into widespread use, nanomaterials will end up in disposal waste streams that are ultimately discharged to the environment. One possible end-of-life scenario is incineration. This review attempts to ascertain the potential pathways by which ...

  4. Plasmonic nanomaterials for biodiagnostics

    PubMed Central

    Howes, Philip D.; Rana, Subinoy; Stevens, Molly M.

    2017-01-01

    The application of nanomaterials to detect disease biomarkers is giving rise to ultrasensitive assays, with scientists exploiting the many advantageous physical and chemical properties of nanomaterials. The fundamental basis of such work is to link unique phenomena that arise at the nanoscale to the presence of a specific analyte biomolecule, and to modulate the intensity of such phenomena in a ratiometric fashion, in direct proportion with analyte concentration. Precise engineering of nanomaterial surfaces is of utmost importance here, as the interface between the material and the biological environment is where the key interactions occur. In this tutorial review, we discuss the use of plasmonic nanomaterials in the development of biodiagnostic tools for the detection of a large variety of biomolecular analytes, and how their plasmonic properties give rise to tunable optical characteristics and surface enhanced Raman signals. We put particular focus on studies that have explored the efficacy of the systems using physiological samples in an effort to highlight the clinical potential of such assays. PMID:24323079

  5. Nanomaterial disposal by incineration

    EPA Science Inventory

    As nanotechnology-based products enter into widespread use, nanomaterials will end up in disposal waste streams that are ultimately discharged to the environment. One possible end-of-life scenario is incineration. This review attempts to ascertain the potential pathways by which ...

  6. Nanomaterials for Electrochemical Immunosensing

    PubMed Central

    Pan, Mingfei; Gu, Ying; Yun, Yaguang; Li, Min; Jin, Xincui; Wang, Shuo

    2017-01-01

    Electrochemical immunosensors resulting from a combination of the traditional immunoassay approach with modern biosensors and electrochemical analysis constitute a current research hotspot. They exhibit both the high selectivity characteristics of immunoassays and the high sensitivity of electrochemical analysis, along with other merits such as small volume, convenience, low cost, simple preparation, and real-time on-line detection, and have been widely used in the fields of environmental monitoring, medical clinical trials and food analysis. Notably, the rapid development of nanotechnology and the wide application of nanomaterials have provided new opportunities for the development of high-performance electrochemical immunosensors. Various nanomaterials with different properties can effectively solve issues such as the immobilization of biological recognition molecules, enrichment and concentration of trace analytes, and signal detection and amplification to further enhance the stability and sensitivity of the electrochemical immunoassay procedure. This review introduces the working principles and development of electrochemical immunosensors based on different signals, along with new achievements and progress related to electrochemical immunosensors in various fields. The importance of various types of nanomaterials for improving the performance of electrochemical immunosensor is also reviewed to provide a theoretical basis and guidance for the further development and application of nanomaterials in electrochemical immunosensors. PMID:28475158

  7. Cytotoxicity of halogenated graphenes

    NASA Astrophysics Data System (ADS)

    Teo, Wei Zhe; Khim Chng, Elaine Lay; Sofer, Zdeněk; Pumera, Martin

    2013-12-01

    Graphene and its family of derivatives possess unique and remarkable physicochemical properties which make them valuable materials for applications in many areas like electronics, energy storage and biomedicine. In response to the possibility of its large-scale manufacturing as commercial products in the future, an investigation was conducted to determine the cytotoxicity of one particular family of graphene derivatives, the halogenated graphenes, for the first time. Halogenated graphenes were prepared through thermal exfoliation of graphite oxide in gaseous chlorine, bromine or iodine atmospheres to yield chlorine- (TRGO-Cl), bromine- (TRGO-Br) and iodine-doped graphene (TRGO-I) respectively. 24 h exposure of human lung carcinoma epithelial cells (A549) to the three halogenated graphenes and subsequent cell viability assessments using methylthiazolyldiphenyl-tetrazolium bromide (MTT) and water-soluble tetrazolium salt (WST-8) assays revealed that all the halogenated graphenes examined are rather cytotoxic at the concentrations tested (3.125 μg mL-1 to 200 μg mL-1) and the effects are dose-dependent, with TRGO-Cl reducing the cell viability to as low as 25.7% at the maximum concentration of 200 μg mL-1. Their levels of cytotoxicity can be arranged in the order of TRGO-Cl > TRGO-Br > TRGO-I, and it is suggested that the amount of halogen present in the graphene material is the determining factor for the observed trend. Control experiments were carried out to test for possible nanomaterial-induced interference as a consequence of reaction between the halogenated graphenes and the viability markers (MTT/WST-8 reagent) or binding of the formazan products under cell-free conditions. The data obtained eliminate the probability of significant influence by these interferents as the change in the normalized percentage of formazan formed is relatively small and thorough washings were performed prior to the viability assessments to reduce the amount of halogenated

  8. Nanomaterials for reducing amyloid cytotoxicity.

    PubMed

    Zhang, Min; Mao, Xiaobo; Yu, Yue; Wang, Chen-Xuan; Yang, Yan-Lian; Wang, Chen

    2013-07-26

    This review is intended to reflect the recent progress on therapeutic applications of nanomaterials in amyloid diseases. The progress on anti-amyloid functions of various nanomaterials including inorganic nanoparticles, polymeric nanoparticles, carbon nanomaterials and biomolecular aggregates, is reviewed and discussed. The main functionalization strategies for general nanoparticle modifications are reviewed for potential applications of targeted therapeutics. The interaction mechanisms between amyloid peptides and nanomaterials are discussed from the perspectives of dominant interactions and kinetics. The encapsulation of anti-amyloid drugs, targeted drug delivery, controlled drug release and drug delivery crossing blood brain barrier by application of nanomaterials would also improve the therapeutics of amyloid diseases.

  9. Synthesis, characterization, and biosensing application of novel hybrid nanomaterials

    NASA Astrophysics Data System (ADS)

    Mao, Shun

    Hybrid nanomaterials consisting of nanoparticles (NPs) distributed on the surface of the carbon nanotube (CNT)/graphene represent a new class of materials. These materials could potentially display not only the unique properties of NPs and those of the CNT/graphene, but also additional novel properties due to the interaction between the NP and the CNT/graphene. This thesis entails the synthesis and characterization of NP-CNT/graphene hybrid nanomaterials and the demonstration of their use for biosensors. A simple method that combines an electrospray technique with electrostatic force directed assembly (ESFDA) was developed for successful functionalization of the CNT/thermally-reduced graphene oxide (TRGO) with NPs. Colloidal CdSe NPs, Au NPs, and Au NP-antibody conjugates were electrosprayed and assembled onto random CNTs, vertically-aligned CNT arrays, and TRGO sheets in a controlled manner. CNT and TRGO field-effect transistors (FETs) were fabricated; and novel electronic protein biosensors based on the CNTFET/TRGO FET and Au NP-antibody conjugates were demonstrated. The electrical detection of the protein binding was accomplished by the introduction of Au NP-antibody conjugates in the CNTFET/TRGO FET, in which the Au-coated CNT/TRGO serves as the electrical conducting channel. Antibody (anti-horseradish peroxidase/anti-Immunoglobulin G) and antigen (horseradish peroxidase/Immunoglobulin G) binding events led to the change in the CNT/TRGO conductivity, which was sensitively detected by FET and direct current (dc) measurements. The CNTFET biosensor had a detection limit of 0.2 mg/ml (˜4.5 microM, horseradish peroxidase) while the TRGO FET biosensor exhibited a detection limit of 2 ng/ml (˜13 pM, Immunoglobulin G), which is among the best of carbon nanomaterial (e.g., CNT, graphene, GO)-based protein sensors. The dependence of the sensor response on the TRGO resistance and the antibody areal density on the TRGO sheet was systematically studied, and the sensor

  10. Colloidal nanomaterial-based immunoassay.

    PubMed

    Teste, Bruno; Descroix, Stephanie

    2012-06-01

    Nanomaterials have been widely developed for their use in nanomedicine, especially for immunoassay-based diagnosis. In this review we focus on the use of nanomaterials as a nanoplatform for colloidal immunoassays. While conventional heterogeneous immunoassays suffer from mass transfer limitations and consequently long assay time, colloidal immunosupports allow target capture in the entire volume, thus speeding up reaction kinetics and shortening assay time. Owing to their wide range of chemical and physical properties, nanomaterials are an interesting candidate for immunoassay development. The most popular colloidal nanomaterials for colloidal immunoassays will be discussed, as well as their influence on immune reactions. Recent advances in nanomaterial applications for different formats of immunoassays will be reported, such as nanomaterial-based indirect immunoassays, optical-based agglutination immunoassays, resonance energy transfer-based immunoassays and magnetic relaxation-based immunoassays. Finally, the future of using nanomaterials for homogeneous immunoassays dedicated to clinical diagnosis will be discussed.

  11. Metabolomic Analysis of Liver Cells Exposed to Carbon Nanotubes and Graphene Oxide

    EPA Science Inventory

    Carbon nanotubes (CNTs) and other graphenic nanomaterials are being used extensively in industrial, consumer, and mechanical applications based in part on their unique structural, optical and electronic properties. Due to the widespread use of these nanoparticles (NPs), human and...

  12. Metabolomic Analysis of Liver Cells Exposed to Carbon Nanotubes and Graphene Oxide

    EPA Science Inventory

    Carbon nanotubes (CNTs) and other graphenic nanomaterials are being used extensively in industrial, consumer, and mechanical applications based in part on their unique structural, optical and electronic properties. Due to the widespread use of these nanoparticles (NPs), human and...

  13. Chemical modifications and bioconjugate reactions of nanomaterials for sensing, imaging, drug delivery and therapy.

    PubMed

    Biju, Vasudevanpillai

    2014-02-07

    As prepared nanomaterials of metals, semiconductors, polymers and carbon often need surface modifications such as ligand exchange, and chemical and bioconjugate reactions for various biosensor, bioanalytical, bioimaging, drug delivery and therapeutic applications. Such surface modifications help us to control the physico-chemical, toxicological and pharmacological properties of nanomaterials. Furthermore, introduction of various reactive functional groups on the surface of nanomaterials allows us to conjugate a spectrum of contrast agents, antibodies, peptides, ligands, drugs and genes, and construct multifunctional and hybrid nanomaterials for the targeted imaging and treatment of cancers. This tutorial review is intended to provide an introduction to newcomers about how chemical and bioconjugate reactions transform the surface of nanomaterials such as silica nanoparticles, gold nanoparticles, gold quantum clusters, semiconductor quantum dots, carbon nanotubes, fullerene and graphene, and accordingly formulate them for applications such as biosensing, bioimaging, drug and gene delivery, chemotherapy, photodynamic therapy and photothermal therapy. Nonetheless, controversial reports and our growing concerns about toxicity and pharmacokinetics of nanomaterials suggest the need for not only rigorous in vivo experiments in animal models but also novel nanomaterials for practical applications in the clinical settings. Further reading of original and review articles cited herein is necessary to buildup in-depth knowledge about the chemistry, bioconjugate chemistry and biological applications of individual nanomaterials.

  14. Resolving Atomic Connectivity in Graphene Nanostructure Junctions.

    PubMed

    Dienel, Thomas; Kawai, Shigeki; Söde, Hajo; Feng, Xinliang; Müllen, Klaus; Ruffieux, Pascal; Fasel, Roman; Gröning, Oliver

    2015-08-12

    We report on the structural characterization of junctions between atomically well-defined graphene nanoribbons (GNRs) by means of low-temperature, noncontact scanning probe microscopy. We show that the combination of simultaneously acquired frequency shift and tunneling current maps with tight binding (TB) simulations allows a comprehensive characterization of the atomic connectivity in the GNR junctions. The proposed approach can be generally applied to the investigation of graphene nanomaterials and their interconnections and is thus expected to become an important tool in the development of graphene-based circuitry.

  15. Functionalized carbon nanomaterials derived from carbohydrates.

    PubMed

    Jagadeesan, Dinesh; Eswaramoorthy, Muthusamy

    2010-02-01

    A tremendous growth in the field of carbon nanomaterials has led to the emergence of carbon nanotubes, fullerenes, mesoporous carbon and more recently graphene. Some of these materials have found applications in electronics, sensors, catalysis, drug delivery, composites, and so forth. The high temperatures and hydrocarbon precursors involved in their synthesis usually yield highly inert graphitic surfaces. As some of the applications require functionalization of their inert graphitic surface with groups like -COOH, -OH, and -NH(2), treatment of these materials in oxidizing agents and concentrated acids become inevitable. More recent works have involved using precursors like carbohydrates to produce carbon nanostructures rich in functional groups in a single-step under hydrothermal conditions. These carbon nanostructures have already found many applications in composites, drug delivery, materials synthesis, and Li ion batteries. The review aims to highlight some of the recent developments in the application of carbohydrate derived carbon nanostructures and also provide an outlook of their future prospects.

  16. Modification of conductive polyaniline with carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Sedaghat, Sajjad; Alavijeh, Mahdi Soleimani

    2014-08-01

    The synthesis of polyaniline/single-wall nanotube, polyaniline/multi-wall nanotube and polyaniline/single-wall nanotube/graphen nanosheets nanocomposites by in situ polymerization are reported in this study. The substrates were treated with a mixture of concentrated sulfuric acid and concentrated nitric acid before usage to functionalize with carboxylic and hydroxyl groups. Aniline monomers are adsorbed and polymerized on the surface of these fillers. Structural analysis using scanning electron microscopy showed that nanomaterials dispersed into polymer matrix and made tubular structures with diameters several tens to hundreds nanometers depending on the polyaniline content. These nanocomposites can be used for production of excellent electrode materials applications in high-performance supercapacitors.

  17. Films of Carbon Nanomaterials for Transparent Conductors

    PubMed Central

    Ho, Xinning; Wei, Jun

    2013-01-01

    The demand for transparent conductors is expected to grow rapidly as electronic devices, such as touch screens, displays, solid state lighting and photovoltaics become ubiquitous in our lives. Doped metal oxides, especially indium tin oxide, are the commonly used materials for transparent conductors. As there are some drawbacks to this class of materials, exploration of alternative materials has been conducted. There is an interest in films of carbon nanomaterials such as, carbon nanotubes and graphene as they exhibit outstanding properties. This article reviews the synthesis and assembly of these films and their post-treatment. These processes determine the film performance and understanding of this platform will be useful for future work to improve the film performance. PMID:28809267

  18. Two- and Three-Dimensional All-Carbon Nanomaterial Assemblies for Tissue Engineering and Regenerative Medicine.

    PubMed

    Lalwani, Gaurav; Patel, Sunny C; Sitharaman, Balaji

    2016-06-01

    Carbon nanomaterials such as carbon nanotubes and graphene have gained significant interest in the fields of materials science, electronics and biomedicine due to their interesting physiochemical properties. Typically these carbon nanomaterials have been dispersed in polymeric matrices at low concentrations to improve the functional properties of nanocomposites employed as two-dimensional (2D) substrates or three-dimensional (3D) porous scaffolds for tissue engineering applications. There has been a growing interest in the assembly of these nanomaterials into 2D and 3D architectures without the use of polymeric matrices, surfactants or binders. In this article, we review recent advances in the development of 2D or 3D all-carbon assemblies using carbon nanotubes or graphene as nanoscale building-block biomaterials for tissue engineering and regenerative medicine applications.

  19. Immobilization Techniques in the Fabrication of Nanomaterial-Based Electrochemical Biosensors: A Review

    PubMed Central

    Putzbach, William; Ronkainen, Niina J.

    2013-01-01

    The evolution of 1st to 3rd generation electrochemical biosensors reflects a simplification and enhancement of the transduction pathway. However, in recent years, modification of the transducer with nanomaterials has become increasingly studied and imparts many advantages. The sensitivity and overall performance of enzymatic biosensors has improved tremendously as a result of incorporating nanomaterials in their fabrication. Given the unique and favorable qualities of gold nanoparticles, graphene and carbon nanotubes as applied to electrochemical biosensors, a consolidated survey of the different methods of nanomaterial immobilization on transducer surfaces and enzyme immobilization on these species is beneficial and timely. This review encompasses modification of enzymatic biosensors with gold nanoparticles, carbon nanotubes, and graphene. PMID:23580051

  20. Graphene-Induced Pore Formation on Cell Membranes

    NASA Astrophysics Data System (ADS)

    Duan, Guangxin; Zhang, Yuanzhao; Luan, Binquan; Weber, Jeffrey K.; Zhou, Royce W.; Yang, Zaixing; Zhao, Lin; Xu, Jiaying; Luo, Judong; Zhou, Ruhong

    2017-02-01

    Examining interactions between nanomaterials and cell membranes can expose underlying mechanisms of nanomaterial cytotoxicity and guide the design of safer nanomedical technologies. Recently, graphene has been shown to exhibit potential toxicity to cells; however, the molecular processes driving its lethal properties have yet to be fully characterized. We here demonstrate that graphene nanosheets (both pristine and oxidized) can produce holes (pores) in the membranes of A549 and Raw264.7 cells, substantially reducing cell viability. Electron micrographs offer clear evidence of pores created on cell membranes. Our molecular dynamics simulations reveal that multiple graphene nanosheets can cooperate to extract large numbers of phospholipids from the membrane bilayer. Strong dispersion interactions between graphene and lipid-tail carbons result in greatly depleted lipid density within confined regions of the membrane, ultimately leading to the formation of water-permeable pores. This cooperative lipid extraction mechanism for membrane perforation represents another distinct process that contributes to the molecular basis of graphene cytotoxicity.

  1. CE and nanomaterials - Part II: Nanomaterials in CE.

    PubMed

    Adam, Vojtech; Vaculovicova, Marketa

    2017-10-01

    The scope of this two-part review is to summarize publications dealing with CE and nanomaterials together. This topic can be viewed from two broad perspectives, and this article is trying to highlight these two approaches: (i) CE of nanomaterials, and (ii) nanomaterials in CE. The second part aims at summarization of publications dealing with application of nanomaterials for enhancement of CE performance either in terms of increasing the separation resolution or for improvement of the detection. To increase the resolution, nanomaterials are employed as either surface modification of the capillary wall forming open tubular column or as additives to the separation electrolyte resulting in a pseudostationary phase. Moreover, nanomaterials have proven to be very beneficial for increasing also the sensitivity of detection employed in CE or even they enable the detection (e.g., fluorescent tags of nonfluorescent molecules). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Graphene hybrids: synthesis strategies and applications in sensors and sensitized solar cells

    PubMed Central

    Badhulika, Sushmee; Terse-Thakoor, Trupti; Villarreal, Claudia; Mulchandani, Ashok

    2015-01-01

    Graphene exhibits unique 2-D structural, chemical, and electronic properties that lead to its many potential applications. In order to expand the scope of its usage, graphene hybrids which combine the synergetic properties of graphene along with metals/metal oxides and other nanostructured materials have been synthesized and are a widely emerging field of research. This review presents an overview of the recent progress made in the field of graphene hybrid architectures with a focus on the synthesis of graphene-carbon nanotube (G-CNT), graphene-semiconductor nanomaterial (G-SNM), and graphene-metal nanomaterial (G-MNM) hybrids. It attempts to identify the bottlenecks involved and outlines future directions for development and comprehensively summarizes their applications in the field of sensing and sensitized solar cells. PMID:26176007

  3. Progress in Large-Scale Production of Graphene. Part 1: Chemical Methods

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Chopra, Nitin

    2015-01-01

    Graphene is a two-dimensional nanomaterial that has unique electrical, mechanical, thermal, and optical properties. For realizing the practical applications of graphene, one of the major challenges lies in cost-effective production of graphene-based nanomaterials at a large scale. Significant research efforts have been demonstrated in regard to scalable manufacturing of graphene and show strong potential for their commercialization and industrialization. Here, we review the state-of-the-art techniques developed for the scalable production of graphene. This review mainly discusses the top-down techniques including exfoliation of bulk graphite and chemical reduction of graphene oxide. Critical comparison for graphene quality, structure, and yields for different techniques is discussed and specific examples are described in detail.

  4. Graphene Growth and Defects on Ni(111)

    NASA Astrophysics Data System (ADS)

    Batzill, Matthias; Lahiri, Jayeeta

    2011-03-01

    Using scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES) we have investigated the growth of graphene on Ni(111) surfaces by carbon segregation from the bulk. We reveal two distinct growth modes for graphene growth. Between 480 and 650 C graphene forms on clean Ni(111) and below 480 C graphene grows by an in-plane conversion of a surface carbide phase. This is the first time that graphene formation is observed by transformation of a surface carbide. STM indicates that a lattice-matched, one-dimensional in-plane domain boundary between graphene and the carbide forms and graphene grows by replacing Ni-atoms with carbon at this interface. In addition to the growth of graphene we will also briefly discuss atomic-scale defects that can be synthesized in Ni-supported graphene. In particular we emphasize the formation of an extended line-defect with metallic properties.

  5. Characterisation of nanomaterial hydrophobicity using engineered surfaces

    NASA Astrophysics Data System (ADS)

    Desmet, Cloé; Valsesia, Andrea; Oddo, Arianna; Ceccone, Giacomo; Spampinato, Valentina; Rossi, François; Colpo, Pascal

    2017-03-01

    Characterisation of engineered nanomaterials (NMs) is of outmost importance for the assessment of the potential risks arising from their extensive use. NMs display indeed a large variety of physico-chemical properties that drastically affect their interaction with biological systems. Among them, hydrophobicity is an important property that is nevertheless only slightly covered by the current physico-chemical characterisation techniques. In this work, we developed a method for the direct characterisation of NM hydrophobicity. The determination of the nanomaterial hydrophobic character is carried out by the direct measurement of the affinity of the NMs for different collectors. Each collector is an engineered surface designed in order to present specific surface charge and hydrophobicity degrees. Being thus characterised by a combination of surface energy components, the collectors enable the NM immobilisation with surface coverage in relation to their hydrophobicity. The experimental results are explained by using the extended DLVO theory, which takes into account the hydrophobic forces acting between NMs and collectors.

  6. The nanomaterial characterization bottleneck.

    PubMed

    Richman, Erik K; Hutchison, James E

    2009-09-22

    The future of nanotechnology rests upon approaches to making new, useful nanomaterials and testing them in complex systems. Currently, the advance from discovery to application is constrained in nanomaterials relative to a mature market, as seen in molecular and bulk matter. To reap the benefits of nanotechnology, improvements in characterization are needed to increase throughput as creativity outpaces our ability to confirm results. The considerations of research, commerce, and regulation are part of a larger feedback loop that illustrates a mutual need for rapid, easy, and standardized characterization of a large property matrix. Now, we have an opportunity and a need to strike a new balance that drives higher quality research, simplifies commercial exploitation, and allows reasoned regulatory approaches.

  7. Engineering epitaxial graphene with oxygen

    NASA Astrophysics Data System (ADS)

    Kimouche, Amina; Martin, Sylvain; Winkelmann, Clemens; Fruchart, Olivier; Courtois, Hervé; Coraux, Johann; Hybrid system at low dimension Team

    2013-03-01

    Almost free-standing graphene can be obtained on metals by decoupling graphene from its substrate, for instance by intercalation of atoms beneath graphene, as it was shown with oxygen atoms. We show that the interaction of oxygen with epitaxial graphene on iridium leads to the formation of an ultrathin crystalline oxide extending between graphene and the metallic substrate via the graphene wrinkles. Graphene studied in this work was prepared under ultra-high vacuum by CVD. The samples were studied by combining scanning probe microscopy (STM, AFM) and spatially resolved spectroscopy (Raman, STS). The ultrathin oxide forms a decoupling barrier layer between graphene and Ir, yielding truly free-standing graphene whose hybridization and charge transfers with the substrate have been quenched. Our work presents novel types of graphene-based nanostructures, and opens the route to the transfer-free preparation of graphene directly onto an insulating support contacted to the metallic substrate which could serve as a gate electrode. Work supported by the EU-NMP GRENADA project

  8. Center for Functional Nanomaterials

    SciTech Connect

    BNL

    2008-08-12

    Staff from Brookhaven's new Center for Functional Nanomaterials (CFN) describe how this advanced facility will focus on the development and understanding of nanoscale materials. The CFN provides state-of-the-art capabilities for the fabrication and study of nanoscale materials, with an emphasis on atomic-level tailoring to achieve desired properties and functions. The overarching scientific theme of the CFN is the development and understanding of nanoscale materials that address the Nation's challenges in energy security.

  9. Center for Functional Nanomaterials

    ScienceCinema

    BNL

    2016-07-12

    Staff from Brookhaven's new Center for Functional Nanomaterials (CFN) describe how this advanced facility will focus on the development and understanding of nanoscale materials. The CFN provides state-of-the-art capabilities for the fabrication and study of nanoscale materials, with an emphasis on atomic-level tailoring to achieve desired properties and functions. The overarching scientific theme of the CFN is the development and understanding of nanoscale materials that address the Nation's challenges in energy security.

  10. Colloidal Stability of Graphene Oxide Nanosheets in Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Guikema, Janice; Wang, Yung-Li; Chen, Kai

    2013-03-01

    Carbon-based nanomaterials are increasingly used in commercial products as well as in research and industrial applications. Due to its extraordinary properties, graphene has attracted intense research interest and has been demonstrated in many potential applications including solar cells, conductive ink, and transistors. Graphene oxide has also been studied extensively and has been used to produce biocompatible antibacterial paper. Chemical reduction of graphene oxide is commonly used to produce inexpensive graphene in large quantities. With the increasing use of graphene and graphene oxide in consumer products, these nanomaterials may inevitably be released to aqueous systems, resulting in potential risk to environmental ecosystems and human health. The fate and mobility of graphene and its oxides in aquatic systems is dependent on their colloidal stability. We will discuss our study of the early-stage aggregation kinetics of graphene oxide in aqueous solutions. We prepared a suspension of single-layer graphene oxide nanosheets in water and used time-resolved dynamic light scattering to study the influence of electrolytes and pH on the aggregation kinetics of the nanosheets. Atomic force microscopy was employed to further examine the graphene oxide nanosheets.

  11. Engineered Carbon-Nanomaterial-Based Electrochemical Sensors for Biomolecules.

    PubMed

    Tiwari, Jitendra N; Vij, Varun; Kemp, K Christian; Kim, Kwang S

    2016-01-26

    The study of electrochemical behavior of bioactive molecules has become one of the most rapidly developing scientific fields. Biotechnology and biomedical engineering fields have a vested interest in constructing more precise and accurate voltammetric/amperometric biosensors. One rapidly growing area of biosensor design involves incorporation of carbon-based nanomaterials in working electrodes, such as one-dimensional carbon nanotubes, two-dimensional graphene, and graphene oxide. In this review article, we give a brief overview describing the voltammetric techniques and how these techniques are applied in biosensing, as well as the details surrounding important biosensing concepts of sensitivity and limits of detection. Building on these important concepts, we show how the sensitivity and limit of detection can be tuned by including carbon-based nanomaterials in the fabrication of biosensors. The sensing of biomolecules including glucose, dopamine, proteins, enzymes, uric acid, DNA, RNA, and H2O2 traditionally employs enzymes in detection; however, these enzymes denature easily, and as such, enzymeless methods are highly desired. Here we draw an important distinction between enzymeless and enzyme-containing carbon-nanomaterial-based biosensors. The review ends with an outlook of future concepts that can be employed in biosensor fabrication, as well as limitations of already proposed materials and how such sensing can be enhanced. As such, this review can act as a roadmap to guide researchers toward concepts that can be employed in the design of next generation biosensors, while also highlighting the current advancements in the field.

  12. Capillary electrophoresis and nanomaterials - Part I: Capillary electrophoresis of nanomaterials.

    PubMed

    Adam, Vojtech; Vaculovicova, Marketa

    2017-10-01

    Nanomaterials are in analytical science used for a broad range of purposes, covering the area of sample pretreatment as well as separation, detection, and identification of target molecules. This part of the review covers capillary electrophoresis (CE) of nanomaterials and focuses on the application of CE as a method for characterization used during nanomaterial synthesis and modification as well as the monitoring of their properties and interactions with other molecules. The heterogeneity of the nanomaterial family is extremely large. Depending on different definitions of the term Nanomaterial/Nanoparticle, the group may cover metal and polymeric nanoparticles, carbon nanomaterials, liposomes and even dendrimers. Moreover, these nanomaterials are usually subjected to some kind of surface modification or functionalization, which broadens the diversity even more. Not only for purposes of verification of nanomaterial synthesis and batch-to-batch quality check, but also for determination the polydispersity and for functionality characterization on the nanoparticle surface, has CE offered very beneficial capabilities. Finally, the monitoring of interactions between nanomaterials and other (bio)molecules is easily performed by some kind of capillary electromigration technique. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Thermal conduction in graphene and graphene multilayers

    NASA Astrophysics Data System (ADS)

    Ghosh, Suchismita

    There has been increasing interest in thermal conductivity of materials motivated by the heat removal issues in electronics and by the need of fundamental science to understand heat conduction at nanoscale [1, 2, 3]. This dissertation reports the results of the experimental investigation of heat conduction in graphene and graphene multilayers. Graphene is a planar single sheet of sp2-bonded carbon atoms arranged in honeycomb lattice. It reveals many unique properties, including the extraordinarily high carrier mobility. In order to measure the thermal conductivity of graphene we developed an original non-contact technique based on micro-Raman spectroscopy. The samples for this study were prepared by mechanical exfoliation and suspended across trenches in Si/SiO2 substrates. The number of atomic planes was determined by deconvolution of the Raman 2D band. The suspended graphene flakes attached to the heat sinks were heated by the laser light focused in the middle. The Raman G peak's temperature sensitivity allowed us to monitor the local temperature change produced by the variation of the excitation laser power. A special calibration procedure was developed to determine the fraction of power absorbed by graphene. Our measurements revealed that single-layer graphene has an extremely high room-temperature thermal conductivity in the range 3800-5300 W/mK depending on the flake size and quality. It was also found that most of the heat near room temperature is transferred by acoustic phonons rather than electrons. Theoretical studies of the phonon thermal conduction in graphene, which included detail treatment of the Umklapp scattering, are in agreement with our experiments. The measurements were also extended to few-layer graphene. It was shown that the thermal conductivity reduces with the increasing number of layers approaching the bulk graphite limit. To validate the measurement technique we investigated the thermal conductivity of the polycrystalline graphene films

  14. Towards application of one- and two-dimensional nanomaterials for reinforcement of polymeric nanocomposite bone grafts

    NASA Astrophysics Data System (ADS)

    Farrshid, Behzad

    One- and two-dimensional (1-D and 2-D) nanomaterials possess extraordinary physiochemical properties such as large surface area, excellent mechanical properties, high surface energy and good dispersivity in organic and biological solvents, therefore, they have been extensively used as reinforcing agents to improve the mechanical properties of polymeric scaffolds for bone tissue engineering applications. Carbon nanomaterials such as carbon nanotubes and graphene have been used as reinforcing agents for biodegradable polymeric scaffolds and composites, however, their short- and long-term in vitro cytotoxicity and in vivo biocompatibility is an area of extensive debate. In this study, we have systematically investigated the effects of addition of low concentrations (0.01-0.2 wt. %) of 1-D and 2-D carbon nanomaterials (graphene oxide nanoplatelets, graphene oxide nanoribbons and carbon nanotubes) and inorganic nanomaterials (boron nitride nanotubes, boron nitride nanoplatelers, tungsten disulfide nanotubes and molybdenum disulfide nanoplatelets) on the mechanical properties, cytocompatibility, and bioactivity of poly(propylene fumarate) (PPF) nanocomposites towards their potential applications as porous and nonporous implants for bone tissue engineering. Addition of nanomaterials in the PPF matrix improved the compressive and flexural mechanical properties of non-porous crosslinked PPF nanocomposites and porous PPF scaffolds. Our results suggest that in addition to high surface roughness and surface area of the nanomaterials, the presence of functional groups on the surface of nanomaterials leads to an increased nanomaterial-polymer interaction and a uniform dispersion of nanomaterials in polymer matrix which may be the key factors responsible for an improved mechanical reinforcement. The in vitro studies showed an excellent cytocompatibility for both carbon and inorganic nanomaterial reinforced PPF nanocomposites and scaffolds. Protein adsorption studies and in vitro

  15. Modelling of particle-laden flow inside nanomaterials

    NASA Astrophysics Data System (ADS)

    Chan, Yue; Wylie, Jonathan J.; Xia, Liang; Ren, Yong; Chen, Yung-Tsang

    2016-08-01

    In this paper, we demonstrate the usage of the Nernst-Planck equation in conjunction with mean-field theory to investigate particle-laden flow inside nanomaterials. Most theoretical studies in molecular encapsulation at the nanoscale do not take into account any macroscopic flow fields that are crucial in squeezing molecules into nanostructures. Here, a multi-scale idea is used to address this issue. The macroscopic transport of gas is described by the Nernst-Planck equation, whereas molecular interactions between gases and between the gas and the host material are described using a combination of molecular dynamics simulation and mean-field theory. In particular, we investigate flow-driven hydrogen storage inside doubly layered graphene sheets and graphene-oxide frameworks (GOFs). At room temperature and with slow velocity fields, we find that a single molecular layer is formed almost instantaneously on the inner surface of the graphene sheets, while molecular ligands between GOFs induce multi-layers. For higher velocities, multi-layers are also formed between graphene. For even larger velocities, the cavity of graphene is filled entirely with hydrogen, whereas for GOFs there exist two voids inside each periodic unit. The flow-driven hydrogen storage inside GOFs with various ligand densities is also investigated.

  16. Modelling of particle-laden flow inside nanomaterials

    PubMed Central

    Wylie, Jonathan J.; Xia, Liang; Ren, Yong; Chen, Yung-Tsang

    2016-01-01

    In this paper, we demonstrate the usage of the Nernst–Planck equation in conjunction with mean-field theory to investigate particle-laden flow inside nanomaterials. Most theoretical studies in molecular encapsulation at the nanoscale do not take into account any macroscopic flow fields that are crucial in squeezing molecules into nanostructures. Here, a multi-scale idea is used to address this issue. The macroscopic transport of gas is described by the Nernst–Planck equation, whereas molecular interactions between gases and between the gas and the host material are described using a combination of molecular dynamics simulation and mean-field theory. In particular, we investigate flow-driven hydrogen storage inside doubly layered graphene sheets and graphene-oxide frameworks (GOFs). At room temperature and with slow velocity fields, we find that a single molecular layer is formed almost instantaneously on the inner surface of the graphene sheets, while molecular ligands between GOFs induce multi-layers. For higher velocities, multi-layers are also formed between graphene. For even larger velocities, the cavity of graphene is filled entirely with hydrogen, whereas for GOFs there exist two voids inside each periodic unit. The flow-driven hydrogen storage inside GOFs with various ligand densities is also investigated. PMID:27616926

  17. Carbon nanomaterials-based electrochemical aptasensors.

    PubMed

    Wang, Zonghua; Yu, Jianbo; Gui, Rijun; Jin, Hui; Xia, Yanzhi

    2016-05-15

    Carbon nanomaterials (CNMs) have attracted increasing attention due to their unique electrical, optical, thermal, mechanical and chemical properties. CNMs are extensively applied in electronic, optoelectronic, photovoltaic and sensing devices fields, especially in bioassay technology. These excellent properties significantly depend on not only the functional atomic structures of CNMs, but also the interactions with other materials, such as gold nanoparticles, SiO2, chitosan, etc. This review systematically summarizes applications of CNMs in electrochemical aptasensors (ECASs). Firstly, definition and development of ECASs are introduced. Secondly, different ways of ECASs about working principles, classification and construction of CNMs are illustrated. Thirdly, the applications of different CNMs used in ECASs are discussed. In this review, different types of CNMs are involved such as carbon nanotubes, graphene, graphene oxide, etc. Besides, the newly emerging CNMs and CNMs-based composites are also discoursed. Finally, we demonstrate the future prospects of CNMs-based ECASs, and some suggestions about the near future development of CNMs-based ECASs are highlighted.

  18. Optical and optoelectronic properties of organic nanomaterials

    NASA Astrophysics Data System (ADS)

    Satapathi, Soumitra

    In this dissertation research, organic nanomaterials, such as semiconducting polymer nanoparticles, graphene nanosheets and organic small molecules were successfully utilized for fabrication of organic solar cells, optical sensors and for high contrast imaging of cancer cells. Semiconducting polymer nanoparticles were synthesized by a simple miniemulsion technique. These size controllable polymeric nanoparticles were proven to be able to optimize the morphologies of the bulk heterojunction solar cells and to provide fundamental insight into the evolution of the nanostructures. Highly sensitive optical sensors were fabricated using these polymeric nanoparticles for efficient detection of nitroaromatic explosives, such as 2,4 dinitrotoluene (DNT) and 2,4,6 trinitrotoluene (TNT) in aqueous medium as well as in vapor the phase. Moreover, these water dispersible and fluorescent polymer nanodots were two-photon active and could be internalized by tumor cells as demonstrated by two-photon confocal imaging. In addition to the polymer nanoparticles, the role of the graphene nanosheets in the performance enhancement of dye sensitized solar cells was also investigated. The use of organic small molecules for optical sensing of different nerve gas agents and their potential use in multiphoton imaging of cancer cells were discussed. Controlling material properties at nanoscale for optoelectronics and imaging application as discussed in this dissertation would provide new dimensions in the areas of applied physics and materials science researches.

  19. Quantum mechanical calculation of nanomaterial-ligand interaction energies by molecular fractionation with conjugated caps method

    NASA Astrophysics Data System (ADS)

    Zhang, Dawei

    2017-03-01

    Molecular fractionation with conjugate caps (MFCC) method is introduced for the efficient estimation of quantum mechanical (QM) interaction energies between nanomaterial (carbon nanotube, fullerene, and graphene surface) and ligand (charged and neutral). In the calculations, nanomaterials are partitioned into small fragments and conjugated caps that are properly capped, and the interaction energies can be obtained through the summation of QM calculations of the fragments from which the contribution of the conjugated caps is removed. All the calculations were performed by density functional theory (DFT) and dispersion contributions for the attractive interactions were investigated by dispersion corrected DFT method. The predicted interaction energies by MFCC at each computational level are found to give excellent agreement with full system (FS) calculations with the mean energy deviation just a fractional kcal/mol. The accurate determination of nanomaterial-ligand interaction energies by MFCC suggests that it is an effective method for performing QM calculations on nanomaterial-ligand systems.

  20. Quantum mechanical calculation of nanomaterial-ligand interaction energies by molecular fractionation with conjugated caps method

    PubMed Central

    Zhang, Dawei

    2017-01-01

    Molecular fractionation with conjugate caps (MFCC) method is introduced for the efficient estimation of quantum mechanical (QM) interaction energies between nanomaterial (carbon nanotube, fullerene, and graphene surface) and ligand (charged and neutral). In the calculations, nanomaterials are partitioned into small fragments and conjugated caps that are properly capped, and the interaction energies can be obtained through the summation of QM calculations of the fragments from which the contribution of the conjugated caps is removed. All the calculations were performed by density functional theory (DFT) and dispersion contributions for the attractive interactions were investigated by dispersion corrected DFT method. The predicted interaction energies by MFCC at each computational level are found to give excellent agreement with full system (FS) calculations with the mean energy deviation just a fractional kcal/mol. The accurate determination of nanomaterial-ligand interaction energies by MFCC suggests that it is an effective method for performing QM calculations on nanomaterial-ligand systems. PMID:28300179

  1. Theranostic applications of carbon nanomaterials in cancer: Focus on imaging and cargo delivery.

    PubMed

    Chen, Daiqin; Dougherty, Casey A; Zhu, Kaicheng; Hong, Hao

    2015-07-28

    Carbon based nanomaterials have attracted significant attention over the past decades due to their unique physical properties, versatile functionalization chemistry, and biological compatibility. In this review, we will summarize the current state-of-the-art applications of carbon nanomaterials in cancer imaging and drug delivery/therapy. The carbon nanomaterials will be categorized into fullerenes, nanotubes, nanohorns, nanodiamonds, nanodots and graphene derivatives based on their morphologies. The chemical conjugation/functionalization strategies of each category will be introduced before focusing on their applications in cancer imaging (fluorescence/bioluminescence, magnetic resonance (MR), positron emission tomography (PET), single-photon emission computed tomography (SPECT), photoacoustic, Raman imaging, etc.) and cargo (chemo/gene/therapy) delivery. The advantages and limitations of each category and the potential clinical utilization of these carbon nanomaterials will be discussed. Multifunctional carbon nanoplatforms have the potential to serve as optimal candidates for image-guided delivery vectors for cancer.

  2. Design and application of carbon nanomaterials for photoactive and charge transport layers in organic solar cells

    NASA Astrophysics Data System (ADS)

    Jin, Sunghwan; Jun, Gwang Hoon; Jeon, Seokwoo; Hong, Soon Hyung

    2016-04-01

    Commercialization of organic solar cell (OSC) has faltered due to their low power conversion efficiency (PCE) compared to inorganic solar cell. Low electrical conductivity, low charge mobility, and short-range light absorption of most organic materials limit the PCE of OSCs. Carbon nanomaterials, especially carbon nanotubes (CNTs) and graphenes, are of great interest for use in OSC applications due to their high electrical conductivity, mobility, and unique optical properties for enhancing the performance of OSCs. In this review, recent progress toward the integration of carbon nanomaterials into OSCs is described. The role of carbon nanomaterials and strategies for their integration into various layers of OSCs, including the photoactive layer and charge transport layer, are discussed. Based on these, we also discuss the prospects of carbon nanomaterials for specific OSC layers to maximize the PCE.

  3. Design and application of carbon nanomaterials for photoactive and charge transport layers in organic solar cells.

    PubMed

    Jin, Sunghwan; Jun, Gwang Hoon; Jeon, Seokwoo; Hong, Soon Hyung

    2016-01-01

    Commercialization of organic solar cell (OSC) has faltered due to their low power conversion efficiency (PCE) compared to inorganic solar cell. Low electrical conductivity, low charge mobility, and short-range light absorption of most organic materials limit the PCE of OSCs. Carbon nanomaterials, especially carbon nanotubes (CNTs) and graphenes, are of great interest for use in OSC applications due to their high electrical conductivity, mobility, and unique optical properties for enhancing the performance of OSCs. In this review, recent progress toward the integration of carbon nanomaterials into OSCs is described. The role of carbon nanomaterials and strategies for their integration into various layers of OSCs, including the photoactive layer and charge transport layer, are discussed. Based on these, we also discuss the prospects of carbon nanomaterials for specific OSC layers to maximize the PCE.

  4. Recent advances in superhydrophobic nanomaterials and nanoscale systems.

    PubMed

    Nagappan, Saravanan; Park, Sung Soo; Ha, Chang-Sik

    2014-02-01

    This review describes the recent advances in the field of superhydrophobic nanomaterials and nanoscale systems. The term superhydrophobic is defined from the surface properties when the surface shows the contact angle (CA) higher than 150 degrees. This could be well known from the lotus effect due to the non-stick and self-cleaning properties of the lotus leaf (LL). We briefly introduced the methods of preparing superhydrophobic surfaces using top-down approaches, bottom-up approaches and a combination of top-down and bottom-up approaches and various ways to prepare superhydrophobic nanomaterials and nanoscale systems using the bio-inspired materials, polymer nanocomposites, metal nanoparticles graphene oxide (GO) and carbon nanotubes (CNTs). We also pointed out the recent applications of the superhydrophobic nanomaterials and nanoscale systems in oil-spill capture and separations, self-cleaning and self-healing systems, bio-medicals, anti-icing and anti-corrosive, electronics, catalysis, textile fabrics and papers etc. The review also highlights the visionary outlook for the future development and use of the superhydrophobic nanomaterials and nanoscale systems for a wide variety of applications.

  5. Carbon nanomaterials for advanced energy conversion and storage.

    PubMed

    Dai, Liming; Chang, Dong Wook; Baek, Jong-Beom; Lu, Wen

    2012-04-23

    It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Nanomaterials in the field of design ergonomics: present status.

    PubMed

    Chowdhury, Anirban; Sanjog, J; Reddy, Swathi Matta; Karmakar, Sougata

    2012-01-01

    Application of nanotechnology and nanomaterials is not new in the field of design, but a recent trend of extensive use of nanomaterials in product and/or workplace design is drawing attention of design researchers all over the world. In the present paper, an attempt has been made to describe the diverse use of nanomaterials in product and workplace design with special emphasis on ergonomics (occupational health and safety; thermo-regulation and work efficiency, cognitive interface design; maintenance of workplace, etc.) to popularise the new discipline 'nanoergonomics' among designers, design users and design researchers. Nanoergonomics for sustainable product and workplace design by minimising occupational health risks has been felt by the authors to be an emerging research area in coming years. Use of nanomaterials in the field of design ergonomics is less explored till date. In the present review, an attempt has been made to extend general awareness among ergonomists/designers about applications of nanomaterials/nanotechnology in the field of design ergonomics and about health implications of nanomaterials during their use.

  7. Negative Poisson's ratio in rippled graphene.

    PubMed

    Qin, Huasong; Sun, Yu; Liu, Jefferson Zhe; Li, Mengjie; Liu, Yilun

    2017-03-10

    In this work, we perform molecular dynamics (MD) simulations to study the effect of rippling on the Poisson's ratio of graphene. Due to the atomic scale thickness of graphene, out-of-plane ripples are generated in free standing graphene with topological defects (e.g. heptagons and pentagons) to release the in-plane deformation energy. Through MD simulations, we have found that the Poisson's ratio of rippled graphene decreases upon increasing its aspect ratio η (amplitude over wavelength). For the rippled graphene sheet η = 0.188, a negative Poisson's ratio of -0.38 is observed for a tensile strain up to 8%, while the Poisson's ratio for η = 0.066 is almost zero. During uniaxial tension, the ripples gradually become flat, thus the Poisson's ratio of rippled graphene is determined by the competing factors of the intrinsic positive Poisson's ratio of graphene and the negative Poisson's ratio due to the de-wrinkling effect. Besides, the rippled graphene exhibits excellent fracture strength and toughness. With the combination of its auxetic and excellent mechanical properties, rippled graphene may possess potential for application in nano-devices and nanomaterials.

  8. Synthesis and Modification of Carbon Nanomaterials utilizing Microwave Heating.

    PubMed

    Schwenke, Almut M; Hoeppener, Stephanie; Schubert, Ulrich S

    2015-07-22

    Microwave-assisted synthesis and processing represents a growing field in materials research and successfully entered the field of carbon nanomaterials during the last decade. Due to the strong interaction of carbon materials with microwave radiation, fast heating rates and localized heating can be achieved. These features enable the acceleration of reaction processes, as well as the formation of nanostructures with special morphologies. A comprehensive overview is provided here on the possibilities and achievements in the field of carbon-nanomaterial research when using microwave-based heating approaches. This includes the synthesis and processing of carbon nanotubes and fibers, graphene materials, carbon nanoparticles, and capsules, as well as porous carbon materials. Additionally, the principles of microwave-heating, in particular of carbon materials, are introduced and important issues, i.e., safety and reproducibility, are discussed.

  9. Graphene-plasmon polaritons: From fundamental properties to potential applications

    NASA Astrophysics Data System (ADS)

    Xiao, Sanshui; Zhu, Xiaolong; Li, Bo-Hong; Mortensen, N. Asger

    2016-04-01

    With unique possibilities for controlling light in nanoscale devices, graphene plasmonics has opened new perspectives to the nanophotonics community with potential applications in metamaterials, modulators, photodetectors, and sensors. In this paper, we briefly review the recent exciting progress in graphene plasmonics. We begin with a general description of the optical properties of graphene, particularly focusing on the dispersion of graphene-plasmon polaritons. The dispersion relation of graphene-plasmon polaritons of spatially extended graphene is expressed in terms of the local response limit with an intraband contribution. With this theoretical foundation of graphene-plasmon polaritons, we then discuss recent exciting progress, paying specific attention to the following topics: excitation of graphene plasmon polaritons, electron-phonon interactions in graphene on polar substrates, and tunable graphene plasmonics with applications in modulators and sensors. Finally, we address some of the apparent challenges and promising perspectives of graphene plasmonics.

  10. Sign-tunable Poisson's ratio in semi-fluorinated graphene.

    PubMed

    Qin, Rui; Zheng, Jiaxin; Zhu, Wenjun

    2017-01-07

    Poisson's ratio is a fundamental property of a material which reflects the transverse strain response to the applied axial strain. Negative Poisson's ratio is allowed theoretically, but is rare in nature. Besides the discovery and tailoring of bulk auxetic materials, recent studies have also found a negative Poisson's ratio in nanomaterials, while their negative Poisson's ratio is mainly based on conventional rigid mechanical models as bulk auxetic materials. In this work, we report the existence of in-plane negative Poisson's ratio in a two-dimensional convex structure of newly synthesized semi-fluorinated graphene by using first-principles calculations. In addition, the sign of the Poisson's ratio can be tuned by the applied strain. Interestingly, we find that this unconventional negative Poisson's ratio cannot be explained by conventional rigid mechanical models but originates from the enhanced bond angle strain over the bond strain due to chemical functionalization. This new mechanism of auxetics extends the scope of auxetic nanomaterials and can serve as design principles for future discovery and design of new auxetic materials.

  11. Electrocatalysis at metal nanomaterials

    NASA Astrophysics Data System (ADS)

    Dai, Lin

    Direct liquid fuel cells, such as direct methanol fuel cells and direct formic acid fuel cells, have attracted much attention in the past decades due to the need of clean and efficient power sources. One of the most critical issues in the development of highly efficient fuel cells is to increase the rates of fuel-cell reactions as a commercial product. As a result, the topic of electrocatalysis plays a significant role in the investigations of fuel cell reactions. For methanol oxidation, platinum based nanomaterials are the most important catalysts. For formic acid oxidation, both platinum and palladium based nanomaterials are widely employed as the catalysts. Recently, shape-control of the nanoparticles has become an imperative task due to the fact that most of the reactions in fuel cells are sensitive to the surface structure of the catalysts. Though numerous studies have been conducted in past to elucidate the catalytic activity on the nanomaterials with different shapes, the results are inconclusive. Herein, systematic comparison of catalytic activity toward methanol and formic acid oxidation on shape-controlled cubic platinum-based alloy nanoparticles with different alloy element are reported in this dissertation. Methanol and formic acid oxidation reactions on spherical and cubic Pt-Cu nanoparticles are also studied. Cu-Pd nanoparticles are synthesized through galvanic redox reactions to provide significantly higher and much more stable formic acid oxidation activities. Interparticle distance effect is investigated on two dimensional nanoparticle array electrodes with controlled particle size, which is ideal model system for exploring the interparticle distance effects on the voltammetric behavior and reaction mechanisms.

  12. Nanomaterial-Based Electrochemical Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

    2010-08-31

    This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

  13. Characterisation of nanomaterial hydrophobicity using engineered surfaces.

    PubMed

    Desmet, Cloé; Valsesia, Andrea; Oddo, Arianna; Ceccone, Giacomo; Spampinato, Valentina; Rossi, François; Colpo, Pascal

    2017-01-01

    Characterisation of engineered nanomaterials (NMs) is of outmost importance for the assessment of the potential risks arising from their extensive use. NMs display indeed a large variety of physico-chemical properties that drastically affect their interaction with biological systems. Among them, hydrophobicity is an important property that is nevertheless only slightly covered by the current physico-chemical characterisation techniques. In this work, we developed a method for the direct characterisation of NM hydrophobicity. The determination of the nanomaterial hydrophobic character is carried out by the direct measurement of the affinity of the NMs for different collectors. Each collector is an engineered surface designed in order to present specific surface charge and hydrophobicity degrees. Being thus characterised by a combination of surface energy components, the collectors enable the NM immobilisation with surface coverage in relation to their hydrophobicity. The experimental results are explained by using the extended DLVO theory, which takes into account the hydrophobic forces acting between NMs and collectors. Graphical abstractDetermination of hydrophobicity character of nanomaterials by measuring their affinity to engineered surfaces.

  14. Effect of carbon nanomaterials on the germination and growth of rice plants.

    PubMed

    Nair, Remya; Mohamed, M Sheikh; Gao, Wei; Maekawa, Toru; Yoshida, Yasuhiko; Ajayan, Pulickel M; Kumar, D Sakthi

    2012-03-01

    For the successful diverse applications of different nanomaterials in life sciences, it is necessary to understand the ultimate fate, distribution and potential environmental impacts of manufactured nanomaterials. Phytotoxicity studies using higher plants is an important criterion for understanding the toxicity of engineered nanomaterials. We studied the effects of engineered carbon nanomaterials of various dimensionalities (carbon nanotubes, C60, graphene) on the germination of rice seeds. A pronounced increase in the rate of germination was observed for rice seeds in the presence of some of these carbon nanostructures, in particular the nanotubes. Increased water content was observed in the carbon nanomaterial treated seeds during germination compared to controls. The germinated seeds were then grown in a basal growth medium supplemented with carbon nanomaterials for studying their impact on further seedling growth. Treated seedlings appeared to be healthier with well-developed root and shoot systems compared to control seedlings. Our results indicate the possible use for carbon nanomaterials as enhancers in the growth of rice seedlings.

  15. Experimental investigation of interactions between proteins and carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Sengupta, Bishwambhar

    The global market for nanomaterials based products is forecasted to reach $1 trillion per annum per annum for 2015. Engineered nanomaterials (ENMs) exhibit unique physicochemical properties with potential to impact diverse aspects of society through applications in electronics, renewable energy, and medicine. While the research and proposed applications of ENMs continue to grow rapidly, the health and safety of ENMs still remains a major concern to the public as well as to policy makers and funding agencies. It is now widely accepted that focused efforts are needed for identifying the list of physicochemical descriptors of ENM before they can be evaluated for nanotoxicity and biological response. This task is surprisingly challenging, as many physicochemical properties of ENMs are closely inter related and cannot be varied independently (e.g. increasing the size of an ENM can introduce additional defects). For example, varying toxic response may ensue due to different methods of nanomaterial preparation, dissimilar impurities and defects. Furthermore, the inadvertent coating of proteins on ENM surface in any biological milieu results in the formation of the so-called "protein/bio-corona" which can in turn alter the fate of ENMs and their biological response. Carbon nanomaterials (CNMs) such as carbon nanotubes, graphene, and graphene oxide are widely used ENMs. It is now known that defects in CNMs play an important role not only in materials properties but also in the determination of how materials interact at the nano-bio interface. In this regard, this work investigates the influence of defect-induced hydrophilicity on the bio-corona formation using micro Raman, photoluminescence, infrared spectroscopy, electrochemistry, and molecular dynamics simulations. Our results show that the interaction of proteins (albumin and fibrinogen) with CNMs is strongly influenced by charge transfer between them, inducing protein unfolding which enhances conformational entropy and

  16. Surface engineered two-dimensional and quasi-one-dimensional nanomaterials for electronic and optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Du, Xiang

    As the sizes of individual components in electronic and optoelectronic devices approach nano scale, the performance of the devices is often determined by surface properties due to their large surface-to-volume ratio. Surface phenomena have become one of the cornerstones in nanoelectronic industry. For this reason, research on the surface functionalization has been tremendous amount of growth over the past decades, and promises to be an increasingly important field in the future. Surface functionalization, as an effective technique to modify the surface properties of a material through a physical or chemical approach, exhibits great potential to solve the problems and challenges, and modulate the performance of nanomaterials based functional devices. Surface functionalization drives the developments and applications of modern electronic and optoelectronic devices fabricated by nanomaterials. In this thesis, I demonstrate two surface functionalization approaches, namely, surface transfer doping and H2 annealing, to effectively solve the problems and significantly enhance the performance of 2D (single structure black phosphorus (BP) and heterostructure graphene/Si Schottky junction), and quasi-1D (molybdenum trioxide (MoO 3) nanobelt) nanomaterials based functional devices, respectively. In situ photoelectron spectroscopy (PES) measurements were also carried out to explore the interfacial charge transfer occurring at the interface between the nanostructures and doping layers, and the gap states in MoO 3 thin films, which provides the underlying mechanism to understand and support our device measurement results. In the first part of this thesis, I will discuss the first surface functionalization approach, namely, surface transfer doping, to effectively modulate the ambipolar characteristics of 2D few-layer BP flakes based FETs. The ambipolar characteristics of BP transistors were effectively modulated through in situ surface functionalization with cesium carbonate (Cs2

  17. Nanomaterials, Inflammation and Tissue Engineering

    PubMed Central

    Padmanabhan, Jagannath

    2014-01-01

    Nanomaterials exhibit unique properties that are absent in the bulk material because decreasing material size leads to an exponential increase in surface area, surface area to volume ratio, and effective stiffness, resulting in altered physiochemical properties. Diverse categories of nanomaterials such as nanoparticles, nanoporous scaffolds, nanopatterned surfaces, nanofibers and carbon nanotubes can be generated using advanced fabrication and processing techniques. These materials are being increasingly incorporated in tissue engineering scaffolds to facilitate the development of biomimetic substitutes to replace damaged tissues and organs. Long term success of nanomaterials in tissue engineering is contingent upon the inflammatory responses they elicit in vivo. This review seeks to summarize the recent developments in our understanding of biochemical and biophysical attributes of nanomaterials and the inflammatory responses they elicit, with a focus on strategies for nanomaterial design in tissue engineering applications. PMID:25421333

  18. Nanomaterials for bio-functionalized electrodes: recent trends

    SciTech Connect

    Walcarius, Alain; Minteer, Shelley D.; Wang, Joseph; Lin, Yuehe; Merkoci, Arben

    2013-09-10

    This review intends to highlight the interest of nanomaterials for building biologically-modified electrodes. Rather than giving a comprehensive overview of the topic, the present work intends to give a flavour on the most exciting achievements and most recent approaches to get (and use) nanostructured electrode surfaces (or electrodes modified with nano-objects) comprising biomolecules. It will mainly consider nano-engineered functional polymers, nano-sized objects such as nanoparticles, carbon nanotubes, graphene or related materials, as well as template-based nanostructures, as modifiers for bio-functionalised electrodes.

  19. Carbon nanomaterial-based electrochemical biosensors: an overview

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoyin; Dai, Zhihui

    2015-04-01

    Carbon materials on the nanoscale exhibit diverse outstanding properties, rendering them extremely suitable for the fabrication of electrochemical biosensors. Over the past two decades, advances in this area have continuously emerged. In this review, we attempt to survey the recent developments of electrochemical biosensors based on six types of carbon nanomaterials (CNs), i.e., graphene, carbon nanotubes, carbon dots, carbon nanofibers, nanodiamonds and buckminsterfullerene. For each material, representative samples are introduced to expound the different roles of the CNs in electrochemical bioanalytical strategies. In addition, remaining challenges and perspectives for future developments are also briefly discussed.

  20. Health effects of nanomaterials.

    PubMed

    Tetley, T D

    2007-06-01

    With the rapid growth of nanotechnology and future bulk manufacture of nanomaterials comes the need to determine, understand and counteract any adverse health effects of these materials that may occur during manufacture, during use, or accidentally. Nanotechnology is expanding rapidly and will affect many aspects of everyday life; there are already hundreds of products that utilize nanoparticles. Paradoxically, the unique properties that are being exploited (e.g. high surface reactivity and ability to cross cell membranes) might have negative health impacts. The rapid progress in development and use of nanomaterials is not yet matched by toxicological investigations. Epidemiological studies implicate the ultrafine (nano-sized) fraction of particulate air pollution in the exacerbation of cardiorespiratory disease and increased morbidity. Experimental animal studies suggest that the increased concentration of nanoparticles and higher reactive surface area per unit mass, alongside unique chemistry and functionality, is important in the acute inflammatory and chronic response. Some animal models have shown that nanoparticles which are deposited in one organ (e.g. lung and gut) may access the vasculature and target other organs (e.g. brain and liver). The exact relationship between the physicochemistry of a nanoparticle, its cellular reactivity, and its biological and systemic consequences cannot be predicted. It is important to understand such relationships to enjoy the benefits of nanotechnology without being exposed to the hazards.

  1. Shaping electrocatalysis through tailored nanomaterials

    SciTech Connect

    Kang, Yijin; Yang, Peidong; Markovic, Nenad M.; Stamenkovic, Vojislav R.

    2016-09-21

    Electrocatalysis is a subclass of heterogeneous catalysis that is aimed towards increase of the electrochemical reaction rates that are taking place at the surface of electrodes. Real-world electrocatalysts are usually based on precious metals in the form of nanoparticles due to their high surface-to-volume ratio, which enables better utilization of employed materials. Ability to tailor nanostructure of an electrocatalyst is critical in order to tune their electrocatalytic properties. Over the last decade, that has mainly been achieved through implementation of fundamental studies performed on well-defined extended surfaces with distinct single crystalline and polycrystalline structures. Based on these studies, it has been demonstrated that performance of an electrocatalyst could be significantly changed through the control of size, composition, morphology and architecture of employed nanomaterials. Here, this review outlines the following steps in the process of rational development of an efficient electrocatalyst: 1) electrochemical properties of well-defined surfaces, 2) synthesis and characterization of different classes of electrocatalysts, and 3) correlation between physical properties (size, shape, composition and morphology) and electrochemical behavior (adsorption, electrocatalytic activity and durability) of electrocatalyst. In addition, this is a brief summary of the novel research platforms in the development of functional nano materials for energy conversion and storage applications such as fuel cells electrolyzers and batteries.

  2. Shaping electrocatalysis through tailored nanomaterials

    DOE PAGES

    Kang, Yijin; Yang, Peidong; Markovic, Nenad M.; ...

    2016-09-21

    Electrocatalysis is a subclass of heterogeneous catalysis that is aimed towards increase of the electrochemical reaction rates that are taking place at the surface of electrodes. Real-world electrocatalysts are usually based on precious metals in the form of nanoparticles due to their high surface-to-volume ratio, which enables better utilization of employed materials. Ability to tailor nanostructure of an electrocatalyst is critical in order to tune their electrocatalytic properties. Over the last decade, that has mainly been achieved through implementation of fundamental studies performed on well-defined extended surfaces with distinct single crystalline and polycrystalline structures. Based on these studies, it hasmore » been demonstrated that performance of an electrocatalyst could be significantly changed through the control of size, composition, morphology and architecture of employed nanomaterials. Here, this review outlines the following steps in the process of rational development of an efficient electrocatalyst: 1) electrochemical properties of well-defined surfaces, 2) synthesis and characterization of different classes of electrocatalysts, and 3) correlation between physical properties (size, shape, composition and morphology) and electrochemical behavior (adsorption, electrocatalytic activity and durability) of electrocatalyst. In addition, this is a brief summary of the novel research platforms in the development of functional nano materials for energy conversion and storage applications such as fuel cells electrolyzers and batteries.« less

  3. Nonlinear graphene plasmonics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cox, Joel D.; Marini, Andrea; Garcia de Abajo, Javier F.

    2016-09-01

    The combination of graphene's intrinsically-high nonlinear optical response with its ability to support long-lived, electrically tunable plasmons that couple strongly with light has generated great expectations for application of the atomically-thin material to nanophotonic devices. These expectations are mainly reinforced by classical analyses performed using the response derived from extended graphene, neglecting finite-size and nonlocal effects that become important when the carbon layer is structured on the nanometer scale in actual device designs. Based on a quantum-mechanical description of graphene using tight-binding electronic states combined with the random-phase approximation, we show that finite-size effects produce large contributions that increase the nonlinear response associated with plasmons in nanostructured graphene to significantly higher levels than previously thought, particularly in the case of Kerr-type optical nonlinearities. Motivated by this finding, we discuss and compare saturable absorption in extended and nanostructured graphene, with or without plasmonic enhancement, within the context of passive mode-locking for ultrafast lasers. We also explore the possibility of high-harmonic generation in doped graphene nanoribbons and nanoislands, where illumination by an infrared pulse of moderate intensity, tuned to a plasmon resonance, is predicted to generate light at harmonics of order 13 or higher, extending over the visible and UV regimes. Our atomistic description of graphene's nonlinear optical response reveals its complex nature in both extended and nanostructured systems, while further supporting the exceptional potential of this material for nonlinear nanophotonic devices.

  4. Terahertz Dynamics in Carbon Nanomaterials

    NASA Astrophysics Data System (ADS)

    Kono, Junichiro

    2012-02-01

    This NSF Partnerships for International Research and Education (PIRE) project supports a unique interdisciplinary and international partnership investigating terahertz (THz) dynamics in nanostructures. The 0.1 to 10 THz frequency range of the electromagnetic spectrum is where electrical transport and optical transitions merge, offering exciting opportunities to study a variety of novel physical phenomena in condensed matter. By combining THz technology and nanotechnology, we can advance our understanding of THz physics while improving and developing THz devices. Specifically, this PIRE research explores THz dynamics of electrons in carbon nanomaterials, namely, nanotubes and graphene --- low-dimensional, sp^2-bonded carbon systems with unique finite-frequency properties. Japan and the U.S. are global leaders in both THz research and carbon research, and stimulating cooperation is critical to further advance THz science and to commercialize products developed in the lab. However, obstacles exist for international collaboration --- primarily linguistic and cultural barriers --- and this PIRE project aims to address these barriers through the integration of our research and education programs. Our strong educational portfolio endeavours to cultivate interest in nanotechnology amongst young U.S. undergraduate students and encourage them to pursue graduate study and academic research in the physical sciences, especially those from underrepresented groups. Our award-winning International Research Experience for Undergraduates Program, NanoJapan, provides structured research internships in Japanese university laboratories with Japanese mentors --- recognized as a model international education program for science and engineering students. The project builds the skill sets of nanoscience researchers and students by cultivating international and inter-cultural awareness, research expertise, and specific academic interests in nanotechnology. U.S. project partners include Rice

  5. Terms of endearment: Bacteria meet graphene nanosurfaces.

    PubMed

    Tegou, Evangelia; Magana, Maria; Katsogridaki, Alexandra Eleni; Ioannidis, Anastasios; Raptis, Vasilios; Jordan, Sheldon; Chatzipanagiotou, Stylianos; Chatzandroulis, Stavros; Ornelas, Catia; Tegos, George P

    2016-05-01

    Microbial multidrug resistance poses serious risks in returning the human species into the pre-antibiotic era if it remains unsolved. While conventional research approaches to combat infectious diseases have been inadequate, nanomaterials are a promising alternative for the development of sound antimicrobial countermeasures. Graphene, a two-dimensional ultra-thin nanomaterial, possesses excellent electronic and biocompatibility properties, which position it in the biotechnology forefront for diverse applications in biosensing, therapeutics, diagnostics, drug delivery and device development. Yet, several questions remain unanswered. For instance, the way these nanosurfaces interact with the microbial entities is poorly understood. The mechanistic elucidation of this interface seems critical to determine the feasibility of applications under development. Are graphene derivatives appropriate materials to design potent antimicrobial agents, vehicles or effective diagnostic microsensors? Has the partition of major microbial resistance phenotypic determinants been sufficiently investigated? Can toxicity become a limiting factor? Are we getting closer to clinical implementation? To facilitate research conducive to answer such questions, this review describes the features of the graphene-bacterial interaction. An overview on paradigms of graphene-microbial interactions is expected to shed light on the range of materials available, and identify possible applications, serving the ultimate goal to develop deeper understanding and collective conscience for the true capabilities of this nanomaterial platform. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Oxidative Stress and Mitochondrial Activation as the Main Mechanisms Underlying Graphene Toxicity against Human Cancer Cells

    PubMed Central

    2016-01-01

    Due to the development of nanotechnology graphene and graphene-based nanomaterials have attracted the most attention owing to their unique physical, chemical, and mechanical properties. Graphene can be applied in many fields among which biomedical applications especially diagnostics, cancer therapy, and drug delivery have been arousing a lot of interest. Therefore it is essential to understand better the graphene-cell interactions, especially toxicity and underlying mechanisms for proper use and development. This review presents the recent knowledge concerning graphene cytotoxicity and influence on different cancer cell lines. PMID:26649139

  7. Optimal nanomaterial concentration: harnessing percolation theory to enhance polymer nanocomposite performance

    NASA Astrophysics Data System (ADS)

    Nadiv, Roey; Shtein, Michael; Shachar, Gal; Varenik, Maxim; Regev, Oren

    2017-07-01

    A major challenge in nanocomposite research is to predict the optimal nanomaterial concentration (ONC) yielding a maximal reinforcement in a given property. We present a simple approach to identify the ONC based on our finding that it is typically located in close proximity to an abrupt increase in polymer matrix viscosity, termed the rheological percolation threshold, and thus may be used as an indicator of the ONC. This premise was validated by rheological and fractography studies of composites loaded by nanomaterials including graphene nanoribbons or carbon or tungsten disulfide nanotubes. The correlation between in situ viscosity, the rheological percolation threshold concentration and the nanocomposite fractography demonstrates the utility of the method.

  8. Carbon-Supported Copper Nanomaterials: Recyclable Catalysts for Huisgen [3+2] Cycloaddition Reactions.

    PubMed

    Shaygan Nia, Ali; Rana, Sravendra; Döhler, Diana; Jirsa, Franz; Meister, Annette; Guadagno, Liberata; Koslowski, Eik; Bron, Michael; Binder, Wolfgang H

    2015-07-20

    Highly disperse copper nanoparticles immobilized on carbon nanomaterials (CNMs; graphene/carbon nanotubes) were prepared and used as a recyclable and reusable catalyst to achieve Cu(I) -catalyzed [3+2] cycloaddition click chemistry. Carbon nanomaterials with immobilized N-heterocyclic carbene (NHC)-Cu complexes prepared from an imidazolium-based carbene and Cu(I) show excellent stability including high efficiency at low catalyst loading. The catalytic performance evaluated in solution and in bulk shows that both types of Cu-CNMs can function as an effective recyclable catalysts (more than 10 cycles) for click reactions without decomposition and the use of external additives.

  9. Synthesis of graphene-conjugated polymer nanocomposites for electronic device applications.

    PubMed

    Qi, Xiaoying; Tan, Chaoliang; Wei, Jun; Zhang, Hua

    2013-02-21

    Graphene-based polymer nanocomposites have attracted increasing interest because of their superior physicochemical properties over polymers. Semiconductor conjugated polymers (CPs) with excellent dispersibility and stability, and efficient electronic and optical properties have been recently integrated with graphene to form a new class of functional nanomaterials. In this minireview, we will summarize the recent advances in the development of graphene-CP nanocomposites for electronic device applications.

  10. Interfacing nanocarbons with organic and inorganic semiconductors: from nanocrystals/quantum dots to extended tetrathiafulvalenes.

    PubMed

    Katsukis, Georgios; Romero-Nieto, Carlos; Malig, Jenny; Ehli, Christian; Guldi, Dirk M

    2012-08-14

    There is no doubt that the outstanding optical and electronic properties that low-dimensional carbon-based nanomaterials exhibit call for their implementation into optoelectronic devices. However, to harvest the enormous potential of these nanocarbons it is essential to probe them in multifunctional electron donor-acceptor systems, placing particular attention on the interactions between electron donors/electron acceptors and nanocarbons. This feature article outlines challenges and recent breakthroughs in the area of interfacing organic and inorganic semiconductors with low-dimensional nanocarbons that range from fullerenes (0D) and carbon nanotubes (1D) to graphene (2D). In the context of organic semiconductors, we focus on aromatic macrocycles and extended tetrathiafulvalenes, and CdTe nanocrystals/quantum dots represent the inorganic semiconductors. Particular emphasis is placed on designing and probing solar energy conversion nanohybrids.

  11. Nanomaterials for renewable energy

    SciTech Connect

    Chen, Shimou; Li, Liang; Sun, Hanwen; Sun, Jian; Lu, Baowang

    2015-05-19

    With demand for sustainable energy, resource, and environment protection, new material technologies are constantly expanding during the last few couple of decades. An intensive attention has been given by the scientific communities. In particular, nanomaterials are increasingly playing an active role either by increasing the efficiency of the energy storage and conversion processes or by improving the device design and performance. This special issue presents recent research advances in various aspects of energy storage technologies, advanced batteries, fuel cells, solar cell, biofuels, and so on. Design and synthesis of novel materials have demonstrated great impact on the utilization of the sustainable energy, which need to solve the increasing shortage of resource and the issues of environmental pollution.

  12. Nanomaterials for renewable energy

    DOE PAGES

    Chen, Shimou; Li, Liang; Sun, Hanwen; ...

    2015-05-19

    With demand for sustainable energy, resource, and environment protection, new material technologies are constantly expanding during the last few couple of decades. An intensive attention has been given by the scientific communities. In particular, nanomaterials are increasingly playing an active role either by increasing the efficiency of the energy storage and conversion processes or by improving the device design and performance. This special issue presents recent research advances in various aspects of energy storage technologies, advanced batteries, fuel cells, solar cell, biofuels, and so on. Design and synthesis of novel materials have demonstrated great impact on the utilization of themore » sustainable energy, which need to solve the increasing shortage of resource and the issues of environmental pollution.« less

  13. Nanomaterials for Space Exploration Applications

    NASA Technical Reports Server (NTRS)

    Moloney, Padraig G.

    2006-01-01

    Nano-engineered materials are multi-functional materials with superior mechanical, thermal and electrical properties. Nanomaterials may be used for a variety of space exploration applications, including ultracapacitors, active/passive thermal management materials, and nanofiltration for water recovery. Additional applications include electrical power/energy storage systems, hybrid systems power generation, advanced proton exchange membrane fuel cells, and air revitalization. The need for nanomaterials and their growth, characterization, processing and space exploration applications is discussed. Data is presented for developing solid-supported amine adsorbents based on carbon nanotube materials and functionalization of nanomaterials is examined.

  14. Extrinsic and Intrinsic Charge Trapping at the Graphene/Ferroelectric Interface

    NASA Astrophysics Data System (ADS)

    Yusuf, Mohammed Humed; Nielsen, Bent; Dawber, Matthew; Du, Xu

    2015-03-01

    In previous works on graphene ferroelectric field effect transistors (GFeFETs), the characteristics of the devices were found to be largely affected by ``anti-hysteresis'' associated with charge trapping instead of ferroelectric domain switching. In this work, with PbTiO3/SrTiO3 (PTO/STO) superlattices, the effect of surface adsorbates was largely diminished by tuning the transition temperature of superlattices and depositing exfoliated graphene at an elevated temperature. With the removal of such extrinsic charge traps, the impact from the ``intrinsic'' defects of the ferroelectric substrate was revealed, inducing fast (~10 μs) charge-trapping and remaining active even at cryogenic temperatures. The defects manifested themselves as unit-cell deep square pits, which were evident from contact-mode Atomic Force Microscopy (AFM) of the interface. An asymmetry in electron and hole trapping was observed. Optimized superlattice growth conditions minimized the surface defects and subdued the charge trapping associated with it. The result was a robust, ramping speed independent, room temperature ferroelectric switching in GFeFETs. With an ideal interface, the work was further extended to study graphene transport across potential barriers/junctions. This work was supported by NSF (Grant DMR 1105202). Part of this research was carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory.

  15. The Molecular Influence of Graphene and Graphene Oxide on the Immune System Under In Vitro and In Vivo Conditions.

    PubMed

    Dudek, Ilona; Skoda, Marta; Jarosz, Anna; Szukiewicz, Dariusz

    2016-06-01

    Graphene and graphene oxide (GO), due to their physicochemical properties and biocompatibility, can be used as an innovative biomedical material in biodetection, drug distribution in the body, treating neoplasms, regenerative medicine, and in implant surgery. Research on the biomedical use of graphene and GO that has been carried out until now is very promising and shows that carbon nanomaterials present high biocompatibility. However, the intolerance of the immune system to graphene nanomaterials, however low, may in consequence make it impossible to use them in medicine. This paper shows the specific mechanism of the molecular influence of graphene and GO on macrophages and lymphocytes under in vitro and in vivo conditions and their practical application in medicine. Under in vitro conditions graphene and GO cause an increased production of pro-inflammatory cytokines, mainly IL-1, IL-6, IL-10 and TNF-α, as a result of the activation of Toll-like receptors in macrophages. Graphene activates apoptosis in macrophages through the TGFbr/Smad/Bcl-2 pathway and also through JNK kinases that are stimulated by an increase of ROS in the cell or through a signal received by Smad proteins. Under in vivo conditions, graphene nanomaterials induce the development of the local inflammatory reaction and the development of granulomas in parenchymal organs. However, there is a huge discrepancy between the results obtained by different research groups, which requires a detailed analysis. In this work we decided to collect and analyze existing research and tried to explain the discrepancies. Understanding the precise mechanism of how this nanomaterial influences immune system cells allows estimating the potential influence of grapheme and GO on the human body.

  16. Graphene electrochemistry: an overview of potential applications.

    PubMed

    Brownson, Dale A C; Banks, Craig E

    2010-11-01

    Graphene, a 2D nanomaterial that possesses spectacular physical, chemical and thermal properties, has caused immense excitement amongst scientists since its freestanding form was isolated in 2004. With research into graphene rife, it promises enhancements and vast applicability within many industrial aspects. Furthermore, graphene possesses a vast array of unique and highly desirable electrochemical properties, and it is this application that offers the most enthralling and spectacular journey. We present a review of the current literature concerning the electrochemical applications and advancements of graphene, starting with its use as a sensor substrate through to applications in energy production and storage, depicting the truly remarkable journey of a material that has just come of age.

  17. Graphene-based platforms for cancer therapeutics.

    PubMed

    Patel, Sunny C; Lee, Stephen; Lalwani, Gaurav; Suhrland, Cassandra; Chowdhury, Sayan Mullick; Sitharaman, Balaji

    2016-01-01

    Graphene is a multifunctional carbon nanomaterial and could be utilized to develop platform technologies for cancer therapies. Its surface can be covalently and noncovalently functionalized with anticancer drugs and functional groups that target cancer cells and tissue to improve treatment efficacies. Furthermore, its physicochemical properties can be harnessed to facilitate stimulus responsive therapeutics and drug delivery. This review article summarizes the recent literature specifically focused on development of graphene technologies to treat cancer. We will focus on advances at the interface of graphene based drug/gene delivery, photothermal/photodynamic therapy and combinations of these techniques. We also discuss the current understanding in cytocompatibility and biocompatibility issues related to graphene formulations and their implications pertinent to clinical cancer management.

  18. Graphene-based platforms for cancer therapeutics

    PubMed Central

    Patel, Sunny C; Lee, Stephen; Lalwani, Gaurav; Suhrland, Cassandra; Chowdhury, Sayan Mullick; Sitharaman, Balaji

    2016-01-01

    Graphene is a multifunctional carbon nanomaterial and could be utilized to develop platform technologies for cancer therapies. Its surface can be covalently and noncovalently functionalized with anticancer drugs and functional groups that target cancer cells and tissue to improve treatment efficacies. Furthermore, its physicochemical properties can be harnessed to facilitate stimulus responsive therapeutics and drug delivery. This review article summarizes the recent literature specifically focused on development of graphene technologies to treat cancer. We will focus on advances at the interface of graphene based drug/gene delivery, photothermal/photodynamic therapy and combinations of these techniques. We also discuss the current understanding in cytocompatibility and biocompatibility issues related to graphene formulations and their implications pertinent to clinical cancer management. PMID:26769305

  19. Interactions of graphene with mammalian cells: Molecular mechanisms and biomedical insights.

    PubMed

    Zhang, Bo; Wei, Peng; Zhou, Zhixiang; Wei, Taotao

    2016-10-01

    Carbon-based functional nanomaterials have attracted immense scientific interest from many disciplines and, due to their extraordinary properties, have offered tremendous potential in a diverse range of applications. Among the different carbon nanomaterials, graphene is one of the newest and is considered the most important. Graphene, a monolayer material composed of sp(2)-hybridized carbon atoms hexagonally arranged in a two-dimensional structure, can be easily functionalized by chemical modification. Functionalized graphene and its derivatives have been used in diverse nano-biotechnological applications, such as in environmental engineering, biomedicine, and biotechnology. However, the prospective use of graphene-related materials in a biological context requires a detailed comprehension of these materials, which is essential for expanding their biomedical applications in the future. In recent years, the number of biological studies involving graphene-related nanomaterials has rapidly increased. These studies have documented the effects of the biological interactions between graphene-related materials and different organizational levels of living systems, ranging from biomolecules to animals. In the present review, we will summarize the recent progress in understanding mainly the interactions between graphene and cells. The impact of graphene on intracellular components, and especially the uptake and transport of graphene by cells, will be discussed in detail. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Beyond graphene: Electrochemical sensors and biosensors for biomarkers detection.

    PubMed

    Bollella, Paolo; Fusco, Giovanni; Tortolini, Cristina; Sanzò, Gabriella; Favero, Gabriele; Gorton, Lo; Antiochia, Riccarda

    2017-03-15

    Graphene's success has stimulated great interest and research in the synthesis and characterization of graphene-like 2D materials, single and few-atom-thick layers of van der Waals materials, which show fascinating and technologically useful properties. This review presents an overview of recent electrochemical sensors and biosensors based on graphene and on graphene-like 2D materials for biomarkers detection. Initially, we will outline different electrochemical sensors and biosensors based on chemically derived graphene, including graphene oxide and reduced graphene oxide, properly functionalized for improved performances and we will discuss the various strategies to prepare graphene modified electrodes. Successively, we present electrochemical sensors and biosensors based on graphene-like 2D materials, such as boron nitride (BN), graphite-carbon nitride (g-C3N4), transition metal dichalcogenides (TMDs), transition metal oxides and graphane, outlining how the new modified 2D nanomaterials will improve the electrochemical performances. Finally, we will compare the results obtained with different sensors and biosensors for the detection of important biomarkers such as glucose, hydrogen peroxide and cancer biomarkers and highlight the advantages and disadvantages of the use of graphene and graphene-like 2D materials in different sensing platforms. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Deposition of Graphene Nanoparticles in Human Upper Airways

    PubMed Central

    Su, Wei-Chung; Ku, Bon-Ki; Kulkarni, Pramod; Cheng, Yung Sung

    2016-01-01

    Graphene nanomaterials have attracted wide attention in recent years on their application to state-of-the-art technology due to their outstanding physical properties. On the other hand, the nanotoxicity of graphene materials also has rapidly become a serious concern especially in occupational health. Graphene materials inevitably could become airborne in the workplace during manufacturing processes. The inhalation and subsequent deposition of graphene nanoparticles in the human respiratory tract could potentially result in adverse health effects to exposed workers. Therefore, investigating the deposition of graphene nanoparticles in the human airways is considered essential for an integral graphene occupational health study. For this reason, this study carried out a series of airway replica deposition experiments to obtain original data of graphene nanoparticle airway deposition. In this study, size classified graphene nanoparticles were delivered into human airway replicas (both nasal and oral-to-lung airways). The deposition fraction and efficiency of graphene nanoparticle in the airway were obtained by a novel experimental approach. The experimental results acquired showed that the fractional deposition of graphene nanoparticles in airway sections studied were all less than 4%, and the deposition efficiencies in each airway section were generally lower than 0.03. These results implies that the majority of the graphene nanoparticles inhaled into the human respiratory tract could easily penetrate through the head airways as well as the upper part of the tracheobronchial airways and then transit down to the lower lung airways, where undesired biological responses might be induced. PMID:26317666

  2. Microscopic Fuel Particles Produced by Self-Assembly of Actinide Nanoclusters on Carbon Nanomaterials

    SciTech Connect

    Na, Chongzheng

    2016-10-17

    Many consider further development of nuclear power to be essential for sustained development of society; however, the fuel forms currently used are expensive to recycle. In this project, we sought to create the knowledge and knowhow that are needed to produce nanocomposite materials by directly depositing uranium nanoclusters on networks of carbon-­ based nanomaterials. The objectives of the proposed work were to (1) determine the control of uranium nanocluster surface chemistry on nanocomposite formation, (2) determine the control of carbon nanomaterial surface chemistry on nanocomposite formation, and (3) develop protocols for synthesizing uranium-­carbon nanomaterials. After examining a wide variety of synthetic methods, we show that synthesizing graphene-­supported UO2 nanocrystals in polar ethylene glycol compounds by polyol reduction under boiling reflux can enable the use of an inexpensive graphene precursor graphene oxide in the production of uranium-carbon nanocomposites in a one-­pot process. We further show that triethylene glycol is the most suitable solvent for producing nanometer-­sized UO2 crystals compared to monoethylene glycol, diethylene glycol, and polyethylene glycol. Graphene-­supported UO2 nanocrystals synthesized with triethylene glycol show evidence of heteroepitaxy, which can be beneficial for facilitating heat transfer in nuclear fuel particles. Furthermore, we show that graphene-supported UO2 nanocrystals synthesized by polyol reduction can be readily stored in alcohols, preventing oxidation from the prevalent oxygen in air. Together, these methods provide a facile approach for preparing and storing graphene-supported UO nanocrystals for further investigation and development under ambient conditions.

  3. Multiscale mechanics of graphene oxide and graphene based composite films

    NASA Astrophysics Data System (ADS)

    Cao, Changhong

    The mechanical behavior of graphene oxide is length scale dependent: orders of magnitude different between the bulk forms and monolayer counterparts. Understanding the underlying mechanisms plays a significant role in their versatile application. A systematic multiscale mechanical study from monolayer to multilayer, including the interactions between layers of GO, can provide fundamental support for material engineering. In this thesis, an experimental coupled with simulation approach was used to study the multiscale mechanics of graphene oxide (GO) and the methods developed for GO study are proved to be applicable also to mechanical study of graphene based composites. GO is a layered nanomaterial comprised of hierarchical units whose characteristic dimension lies between monolayer GO (0.7 nm - 1.2 nm) and bulk GO papers (≥ 1 mum). Mechanical behaviors of monolayer GO and GO nanosheets (10 nm- 100 nm) were comprehensively studied this work. Monolayer GO was measured to have an average strength of 24.7 GPa,, orders of magnitude higher than previously reported values for GO paper and approximately 50% of the 2D intrinsic strength of pristine graphene. The huge discrepancy between the strength of monolayer GO and that of bulk GO paper motivated the study of GO at the intermediate length scale (GO nanosheets). Experimental results showed that GO nanosheets possess high strength in the gigapascal range. Molecular Dynamic simulations showed that the transition in the failure behavior from interplanar fracture to intraplanar fracture was responsible for the huge strength discrepancy between nanometer scale GO and bulk GO papers. Additionally, the interfacial shear strength between GO layers was found to be a key contributing factor to the distinct mechanical behavior among hierarchical units of GO. The understanding of the multiscale mechanics of GO is transferrable in heterogeneous layered nanomaterials, such as graphene-metal oxide based anode materials in Li

  4. How graphene slides: measurement and theory of strain-dependent frictional forces between graphene and SiO2.

    PubMed

    Kitt, Alexander L; Qi, Zenan; Rémi, Sebastian; Park, Harold S; Swan, Anna K; Goldberg, Bennett B

    2013-06-12

    Strain, bending rigidity, and adhesion are interwoven in determining how graphene responds when pulled across a substrate. Using Raman spectroscopy of circular, graphene-sealed microchambers under variable external pressure, we demonstrate that graphene is not firmly anchored to the substrate when pulled. Instead, as the suspended graphene is pushed into the chamber under pressure, the supported graphene outside the microchamber is stretched and slides, pulling in an annulus. Analyzing Raman G band line scans with a continuum model extended to include sliding, we extract the pressure dependent sliding friction between the SiO2 substrate and mono-, bi-, and trilayer graphene. The sliding friction for trilayer graphene is directly proportional to the applied load, but the friction for monolayer and bilayer graphene is inversely proportional to the strain in the graphene, which is in violation of Amontons' law. We attribute this behavior to the high surface conformation enabled by the low bending rigidity and strong adhesion of few layer graphene.

  5. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite

    PubMed Central

    Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D.; Pumera, Martin

    2012-01-01

    Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research. PMID:22826262

  6. Synthesis and cyto-genotoxicity evaluation of graphene on mice spermatogonial stem cells.

    PubMed

    Hashemi, Ehsan; Akhavan, Omid; Shamsara, Mehdi; Daliri, Morteza; Dashtizad, Mojtaba; Farmany, Abbas

    2016-10-01

    The present study analyzed the dose-dependent cyto- and genotoxicity of graphene oxide and reduced graphene oxide on spermatogonial stem cells (SSCs) for the first time. The results showed that graphene oxide significantly increased oxidative stress at concentrations of 100 and 400μg/ml, while low concentrations did not have a significant effect. In addition, according to the MTT assay, the cell number decreased in high-concentration (100 and 400μg/ml) graphene oxide-treated samples compared to untreated cells. However, a reduced graphene-treated sample demonstrated a significant increase in cell number. Moreover, microscopic analysis found high concentrations of graphene nanosheets in cell culture medium that reduced the number of colonies and colony forming cells. We conclude that a high concentration of graphene can be toxic to SSCs. However, such toxicity can be reduced by the surface modification of graphene nanomaterials. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite.

    PubMed

    Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D; Pumera, Martin

    2012-08-07

    Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research.

  8. Neurotoxicity of manganese oxide nanomaterials

    NASA Astrophysics Data System (ADS)

    Stefanescu, Diana M.; Khoshnan, Ali; Patterson, Paul H.; Hering, Janet G.

    2009-11-01

    Manganese (Mn) toxicity in humans has been observed as manganism, a disease that resembles Parkinson's disease. The mechanism of Mn toxicity and the chemical forms that may be responsible for its neurotoxicity are not well understood. We examined the toxicity of Mn oxide nanomaterials in a neuronal precursor cell model, using the MTS assay to evaluate mitochondrial function in living cells and the LDH assay to quantify the release of the enzyme lactate dehydrogenase as a result of damage to the cell membrane. Both assays show that the toxicity of Mn is dependent on the type of Mn oxide nanomaterial and its concentration as well as on the state of cell differentiation. Following exposure to Mn oxide nanomaterials, reactive oxygen species (ROS) are generated, and flow cytometry experiments suggest that cell death occurred through apoptosis. During exposure to Mn oxide nanomaterials, increased levels of the transcription factor NF-κB (which mediates the cellular inflammatory response) were observed.

  9. Gold-based hybrid nanomaterials for biosensing and molecular diagnostic applications.

    PubMed

    Kim, Jung Eun; Choi, Ji Hye; Colas, Marion; Kim, Dong Ha; Lee, Hyukjin

    2016-06-15

    The properties of gold nanomaterials are particularly of interest to many researchers, since they show unique physiochemical properties such as optical adsorption of specific wavelength of light, high electrical conductance with rich surface electrons, and facile surface modification with sulfhydryl groups. These properties have facilitated the use of gold nanomaterials in the development of various hybrid systems for biosensors and molecular diagnostics. Combined with various synthetic materials such as fluorescence dyes, polymers, oligonucleotides, graphene oxides (GO), and quantum dots (QDs), the gold-based hybrid nanomaterials offer multi-functionalities in molecular detection with high specificity and sensitivity. These two aspects result in the increase of detection speed as well as the lower detection limits, having shown that this diagnosis method is more effective than other conventional ones. In this review, we have highlighted various examples of nanomaterials for biosensing and molecular diagnostics. The gold-based hybrid systems are categorized by three distinct detection approaches, in which include (1) optical, such as surface plasmon resonance (SPR), RAMAN, and surface-enhanced Raman scattering (SERS), (2) fluorescence, such as förster resonance energy transfer (FRET) and nanomaterial surface energy transfer (NSET), and (3) electrochemical, such as potentiometic, amperometric, and conductometric. Each example provides the detailed mechanism of molecular detection as well as the supporting experimental result with the limit of detection (LOD). Lastly, future perspective on novel development of gold-based hybrid nanomaterials is discussed as well as their challenges.

  10. Toxicity of Graphene Shells, Graphene Oxide, and Graphene Oxide Paper Evaluated with Escherichia coli Biotests

    PubMed Central

    Efremova, Ludmila V.; Vasilchenko, Alexey S.; Rakov, Eduard G.; Deryabin, Dmitry G.

    2015-01-01

    The plate-like graphene shells (GS) produced by an original methane pyrolysis method and their derivatives graphene oxide (GO) and graphene oxide paper (GO-P) were evaluated with luminescent Escherichia coli biotests and additional bacterial-based assays which together revealed the graphene-family nanomaterials' toxicity and bioactivity mechanisms. Bioluminescence inhibition assay, fluorescent two-component staining to evaluate cell membrane permeability, and atomic force microscopy data showed GO expressed bioactivity in aqueous suspension, whereas GS suspensions and the GO-P surface were assessed as nontoxic materials. The mechanism of toxicity of GO was shown not to be associated with oxidative stress in the targeted soxS::lux and katG::lux reporter cells; also, GO did not lead to significant mechanical disruption of treated bacteria with the release of intracellular DNA contents into the environment. The well-coordinated time- and dose-dependent surface charge neutralization and transport and energetic disorders in the Escherichia coli cells suggest direct membrane interaction, internalization, and perturbation (i.e., “membrane stress”) as a clue to graphene oxide's mechanism of toxicity. PMID:26221608

  11. Toxicity of Graphene Shells, Graphene Oxide, and Graphene Oxide Paper Evaluated with Escherichia coli Biotests.

    PubMed

    Efremova, Ludmila V; Vasilchenko, Alexey S; Rakov, Eduard G; Deryabin, Dmitry G

    2015-01-01

    The plate-like graphene shells (GS) produced by an original methane pyrolysis method and their derivatives graphene oxide (GO) and graphene oxide paper (GO-P) were evaluated with luminescent Escherichia coli biotests and additional bacterial-based assays which together revealed the graphene-family nanomaterials' toxicity and bioactivity mechanisms. Bioluminescence inhibition assay, fluorescent two-component staining to evaluate cell membrane permeability, and atomic force microscopy data showed GO expressed bioactivity in aqueous suspension, whereas GS suspensions and the GO-P surface were assessed as nontoxic materials. The mechanism of toxicity of GO was shown not to be associated with oxidative stress in the targeted soxS::lux and katG::lux reporter cells; also, GO did not lead to significant mechanical disruption of treated bacteria with the release of intracellular DNA contents into the environment. The well-coordinated time- and dose-dependent surface charge neutralization and transport and energetic disorders in the Escherichia coli cells suggest direct membrane interaction, internalization, and perturbation (i.e., "membrane stress") as a clue to graphene oxide's mechanism of toxicity.

  12. Highly energetic compositions based on functionalized carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Yan, Qi-Long; Gozin, Michael; Zhao, Feng-Qi; Cohen, Adva; Pang, Si-Ping

    2016-02-01

    In recent years, research in the field of carbon nanomaterials (CNMs), such as fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene, and graphene oxide (GO), has been widely used in energy storage, electronics, catalysts, and biomaterials, as well as medical applications. Regarding energy storage, one of the most important research directions is the development of CNMs as carriers of energetic components by coating or encapsulation, thus forming safer advanced nanostructures with better performances. Moreover, some CNMs can also be functionalized to become energetic additives. This review article covers updated preparation methods for the aforementioned CNMs, with a more specific orientation towards the use of these nanomaterials in energetic compositions. The effects of these functionalized CNMs on thermal decomposition, ignition, combustion and the reactivity properties of energetic compositions are significant and are discussed in detail. It has been shown that the use of functionalized CNMs in energetic compositions greatly improves their combustion performances, thermal stability and sensitivity. In particular, functionalized fullerenes, CNTs and GO are the most appropriate candidate components in nanothermites, solid propellants and gas generators, due to their superior catalytic properties as well as facile preparation methods.

  13. Highly energetic compositions based on functionalized carbon nanomaterials.

    PubMed

    Yan, Qi-Long; Gozin, Michael; Zhao, Feng-Qi; Cohen, Adva; Pang, Si-Ping

    2016-03-07

    In recent years, research in the field of carbon nanomaterials (CNMs), such as fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene, and graphene oxide (GO), has been widely used in energy storage, electronics, catalysts, and biomaterials, as well as medical applications. Regarding energy storage, one of the most important research directions is the development of CNMs as carriers of energetic components by coating or encapsulation, thus forming safer advanced nanostructures with better performances. Moreover, some CNMs can also be functionalized to become energetic additives. This review article covers updated preparation methods for the aforementioned CNMs, with a more specific orientation towards the use of these nanomaterials in energetic compositions. The effects of these functionalized CNMs on thermal decomposition, ignition, combustion and the reactivity properties of energetic compositions are significant and are discussed in detail. It has been shown that the use of functionalized CNMs in energetic compositions greatly improves their combustion performances, thermal stability and sensitivity. In particular, functionalized fullerenes, CNTs and GO are the most appropriate candidate components in nanothermites, solid propellants and gas generators, due to their superior catalytic properties as well as facile preparation methods.

  14. Polymer-directed synthesis of metal oxide-containing nanomaterials for electrochemical energy storage.

    PubMed

    Mai, Yiyong; Zhang, Fan; Feng, Xinliang

    2014-01-07

    Metal oxide-containing nanomaterials (MOCNMs) of controllable structures at the nano-scale have attracted considerable interest because of their great potential applications in electrochemical energy storage devices, such as lithium-ion batteries (LIBs) and supercapacitors. Among many structure-directing agents, polymers and macromolecules, including block copolymers (BCPs) and graphene, exhibit distinct advantages in the template-assisted synthesis of MOCNMs. In this feature article, we introduce the controlled preparation of MOCNMs employing BCPs and graphene as structure-directing agents. Typical synthetic strategies are presented for the control of structures and sizes as well as the improvement of physical properties and electrochemical performance of MOCNMs in LIBs and supercapacitors.

  15. Catalytically active nanomaterials: a promising candidate for artificial enzymes.

    PubMed

    Lin, Youhui; Ren, Jinsong; Qu, Xiaogang

    2014-04-15

    Natural enzymes, exquisite biocatalysts mediating every biological process in living organisms, are able to accelerate the rate of chemical reactions up to 10(19) times for specific substrates and reactions. However, the practical application of enzymes is often hampered by their intrinsic drawbacks, such as low operational stability, sensitivity of catalytic activity to environmental conditions, and high costs in preparation and purification. Therefore, the discovery and development of artificial enzymes is highly desired. Recently, the merging of nanotechnology with biology has ignited extensive research efforts for designing functional nanomaterials that exhibit various properties intrinsic to enzymes. As a promising candidate for artificial enzymes, catalytically active nanomaterials (nanozymes) show several advantages over natural enzymes, such as controlled synthesis in low cost, tunability in catalytic activities, as well as high stability against stringent conditions. In this Account, we focus on our recent progress in exploring and constructing such nanoparticulate artificial enzymes, including graphene oxide, graphene-hemin nanocomposites, carbon nanotubes, carbon nanodots, mesoporous silica-encapsulated gold nanoparticles, gold nanoclusters, and nanoceria. According to their structural characteristics, these enzyme mimics are categorized into three classes: carbon-, metal-, and metal-oxide-based nanomaterials. We aim to highlight the important role of catalytic nanomaterials in the fields of biomimetics. First, we provide a practical introduction to the identification of these nanozymes, the source of the enzyme-like activities, and the enhancement of activities via rational design and engineering. Then we briefly describe new or enhanced applications of certain nanozymes in biomedical diagnosis, environmental monitoring, and therapeutics. For instance, we have successfully used these biomimetic catalysts as colorimetric probes for the detection of

  16. Plasma nanofabrication and nanomaterials safety

    NASA Astrophysics Data System (ADS)

    Han, Z. J.; Levchenko, I.; Kumar, S.; Yajadda, M. M. A.; Yick, S.; Seo, D. H.; Martin, P. J.; Peel, S.; Kuncic, Z.; Ostrikov, K.

    2011-05-01

    The fast advances in nanotechnology have raised increasing concerns related to the safety of nanomaterials when exposed to humans, animals and the environment. However, despite several years of research, the nanomaterials safety field is still in its infancy owing to the complexities of structural and surface properties of these nanomaterials and organism-specific responses to them. Recently, plasma-based technology has been demonstrated as a versatile and effective way for nanofabrication, yet its health and environment-benign nature has not been widely recognized. Here we address the environmental and occupational health and safety effects of various zero- and one-dimensional nanomaterials and elaborate the advantages of using plasmas as a safe nanofabrication tool. These advantages include but are not limited to the production of substrate-bound nanomaterials, the isolation of humans from harmful nanomaterials, and the effective reforming of toxic and flammable gases. It is concluded that plasma nanofabrication can minimize the hazards in the workplace and represents a safe way for future nanofabrication technologies.

  17. Radioactive Nanomaterials for Multimodality Imaging

    PubMed Central

    Chen, Daiqin; Dougherty, Casey A.; Yang, Dongzhi; Wu, Hongwei; Hong, Hao

    2016-01-01

    Nuclear imaging techniques, including primarily positron emission tomography (PET) and single-photon emission computed tomography (SPECT), can provide quantitative information for a biological event in vivo with ultra-high sensitivity, however, the comparatively low spatial resolution is their major limitation in clinical application. By convergence of nuclear imaging with other imaging modalities like computed tomography (CT), magnetic resonance imaging (MRI) and optical imaging, the hybrid imaging platforms can overcome the limitations from each individual imaging technique. Possessing versatile chemical linking ability and good cargo-loading capacity, radioactive nanomaterials can serve as ideal imaging contrast agents. In this review, we provide a brief overview about current state-of-the-art applications of radioactive nanomaterials in the circumstances of multimodality imaging. We present strategies for incorporation of radioisotope(s) into nanomaterials along with applications of radioactive nanomaterials in multimodal imaging. Advantages and limitations of radioactive nanomaterials for multimodal imaging applications are discussed. Finally, a future perspective of possible radioactive nanomaterial utilization is presented for improving diagnosis and patient management in a variety of diseases. PMID:27227167

  18. Graphene aerogels

    DOEpatents

    Pauzauskie, Peter J; Worsley, Marcus A; Baumann, Theodore F; Satcher, Jr., Joe H; Biener, Juergen

    2015-03-31

    Graphene aerogels with high conductivity and surface areas including a method for making a graphene aerogel, including the following steps: (1) preparing a reaction mixture comprising a graphene oxide suspension and at least one catalyst; (2) curing the reaction mixture to produce a wet gel; (3) drying the wet gel to produce a dry gel; and (4) pyrolyzing the dry gel to produce a graphene aerogel. Applications include electrical energy storage including batteries and supercapacitors.

  19. Graphene oxide assisted synthesis of GaN nanostructures for reducing cell adhesion.

    PubMed

    Yang, Rong; Zhang, Ying; Li, Jingying; Han, Qiusen; Zhang, Wei; Lu, Chao; Yang, Yanlian; Dong, Hongwei; Wang, Chen

    2013-11-21

    We report a general approach for the synthesis of large-scale gallium nitride (GaN) nanostructures by the graphene oxide (GO) assisted chemical vapor deposition (CVD) method. A modulation effect of GaN nanostructures on cell adhesion has been observed. The morphology of the GaN surface can be controlled by GO concentrations. This approach, which is based on the predictable choice of the ratio of GO to catalysts, can be readily extended to the synthesis of other materials with controllable nanostructures. Cell studies show that GaN nanostructures reduced cell adhesion significantly compared to GaN flat surfaces. The cell-repelling property is related to the nanostructure and surface wettability. These observations of the modulation effect on cell behaviors suggest new opportunities for novel GaN nanomaterial-based biomedical devices. We believe that potential applications will emerge in the biomedical and biotechnological fields.

  20. Probing mechanical principles of cell-nanomaterial interactions

    NASA Astrophysics Data System (ADS)

    Gao, Huajian

    2014-01-01

    With the rapid development of nanotechnology, various types of nanoparticles, nanowires, nanofibers, nanotubes, and atomically thin plates and sheets have emerged as candidates for an ever increasing list of potential applications for next generation electronics, microchips, composites, barrier coatings, biosensors, drug delivery, and energy harvesting and conversion systems. There is now an urgent societal need to understand both beneficial and hazardous effects of nanotechnology which is projected to produce and release thousands of tons of nanomaterials into the environment in the coming decades. This paper aims to present an overview of some recent studies conducted at Brown University on the mechanics of cell-nanomaterial interactions, including the modeling of nanoparticles entering cells by receptor-mediated endocytosis and coarse-grained molecular dynamics simulations of nanoparticles interacting with cell membranes. The discussions will be organized around the following questions: Why and how does cellular uptake of nanoparticles depend on particle size, shape, elasticity and surface structure? In particular, we will discuss the effect of nanoparticle size on receptor-mediated endocytosis, the effect of elastic stiffness on cell-particle interactions, how high aspect ratio nanomaterials such as carbon nanotubes and graphenes enter cells and how different geometrical patterns of ligands on a nanoparticle can be designed to control the rate of particle uptake.

  1. Nanomaterials incorporated ultrasound contrast agents for cancer theranostics.

    PubMed

    Fu, Lei; Ke, Heng-Te

    2016-09-01

    Nanotechnology provides various nanomaterials with tremendous functionalities for cancer diagnostics and therapeutics. Recently, theranostics has been developed as an alternative strategy for efficient cancer treatment through combination of imaging diagnosis and therapeutic interventions under the guidance of diagnostic results. Ultrasound (US) imaging shows unique advantages with excellent features of real-time imaging, low cost, high safety and portability, making US contrast agents (UCAs) an ideal platform for construction of cancer theranostic agents. This review focuses on the development of nanomaterials incorporated multifunctional UCAs serving as theranostic agents for cancer diagnostics and therapeutics, via conjugation of superparamagnetic iron oxide nanoparticles (SPIOs), CuS nanoparticles, DNA, siRNA, gold nanoparticles (GNPs), gold nanorods (GNRs), gold nanoshell (GNS), graphene oxides (GOs), polypyrrole (PPy) nanocapsules, Prussian blue (PB) nanoparticles and so on to different types of UCAs. The cancer treatment could be more effectively and accurately carried out under the guidance and monitoring with the help of the achieved theranostic agents. Furthermore, nanomaterials incorporated theranostic agents based on UCAs can be designed and constructed by demand for personalized and accurate treatment of cancer, demonstrating their great potential to address the challenges of cancer heterogeneity and adaptation, which can provide alternative strategies for cancer diagnosis and therapeutics.

  2. Nanomaterials incorporated ultrasound contrast agents for cancer theranostics

    PubMed Central

    Fu, Lei; Ke, Heng-Te

    2016-01-01

    Nanotechnology provides various nanomaterials with tremendous functionalities for cancer diagnostics and therapeutics. Recently, theranostics has been developed as an alternative strategy for efficient cancer treatment through combination of imaging diagnosis and therapeutic interventions under the guidance of diagnostic results. Ultrasound (US) imaging shows unique advantages with excellent features of real-time imaging, low cost, high safety and portability, making US contrast agents (UCAs) an ideal platform for construction of cancer theranostic agents. This review focuses on the development of nanomaterials incorporated multifunctional UCAs serving as theranostic agents for cancer diagnostics and therapeutics, via conjugation of superparamagnetic iron oxide nanoparticles (SPIOs), CuS nanoparticles, DNA, siRNA, gold nanoparticles (GNPs), gold nanorods (GNRs), gold nanoshell (GNS), graphene oxides (GOs), polypyrrole (PPy) nanocapsules, Prussian blue (PB) nanoparticles and so on to different types of UCAs. The cancer treatment could be more effectively and accurately carried out under the guidance and monitoring with the help of the achieved theranostic agents. Furthermore, nanomaterials incorporated theranostic agents based on UCAs can be designed and constructed by demand for personalized and accurate treatment of cancer, demonstrating their great potential to address the challenges of cancer heterogeneity and adaptation, which can provide alternative strategies for cancer diagnosis and therapeutics. PMID:27807499

  3. Evaluation of antibacterial effects of carbon nanomaterials against copper-resistant Ralstonia solanacearum.

    PubMed

    Wang, Xiuping; Liu, Xueqin; Han, Heyou

    2013-03-01

    In this paper, we investigated the antibacterial activity and the action mode of carbon nanomaterials (CNMs) against the copper-resistant plant pathogenic bacterium Ralstonia solanacearum (R. solanacearum). Single-walled carbon nanotubes (SWCNTs) dispersion was found to show the strongest antibacterial activity, sequentially followed by graphene oxide (GO), multi-walled carbon nanotubes (MWCNTs), reduced graphene oxide (rGO) and fullerene (C(60)). Our investigation of the antibacterial mechanism of SWCNTs and GO indicated that the damage to the cell membrane leads to the release of cytoplasm materials from the bacterium, which is the causative factor for the inactivation of R. solanacearum bacterial cells. The superior antibacterial effect, and the novel antibacterial mode of SWCNTs and GO suggest that those carbon nanomaterials may have important applications in the control of plant bacterial diseases. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  4. PREFACE: Ultrafast and nonlinear optics in carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Kono, Junichiro

    2013-02-01

    Carbon-based nanomaterials—single-wall carbon nanotubes (SWCNTs) and graphene, in particular—have emerged in the last decade as novel low-dimensional systems with extraordinary properties. Because they are direct-bandgap systems, SWCNTs are one of the leading candidates to unify electronic and optical functions in nanoscale circuitry; their diameter-dependent bandgaps can be utilized for multi-wavelength devices. Graphene's ultrahigh carrier mobilities are promising for high-frequency electronic devices, while, at the same time, it is predicted to have ideal properties for terahertz generation and detection due to its unique zero-gap, zero-mass band structure. There have been a large number of basic optical studies on these materials, but most of them were performed in the weak-excitation, quasi-equilibrium regime. In order to probe and assess their performance characteristics as optoelectronic materials under device-operating conditions, it is crucial to strongly drive them and examine their optical properties in highly non-equilibrium situations and with ultrashot time resolution. In this section, the reader will find the latest results in this rapidly growing field of research. We have assembled contributions from some of the leading experts in ultrafast and nonlinear optical spectroscopy of carbon-based nanomaterials. Specific topics featured include: thermalization, cooling, and recombination dynamics of photo-generated carriers; stimulated emission, gain, and amplification; ultrafast photoluminescence; coherent phonon dynamics; exciton-phonon and exciton-plasmon interactions; exciton-exciton annihilation and Auger processes; spontaneous and stimulated emission of terahertz radiation; four-wave mixing and harmonic generation; ultrafast photocurrents; the AC Stark and Franz-Keldysh effects; and non-perturbative light-mater coupling. We would like to express our sincere thanks to those who contributed their latest results to this special section, and the

  5. Chiral Graphene Quantum Dots.

    PubMed

    Suzuki, Nozomu; Wang, Yichun; Elvati, Paolo; Qu, Zhi-Bei; Kim, Kyoungwon; Jiang, Shuang; Baumeister, Elizabeth; Lee, Jaewook; Yeom, Bongjun; Bahng, Joong Hwan; Lee, Jaebeom; Violi, Angela; Kotov, Nicholas A

    2016-02-23

    Chiral nanostructures from metals and semiconductors attract wide interest as components for polarization-enabled optoelectronic devices. Similarly to other fields of nanotechnology, graphene-based materials can greatly enrich physical and chemical phenomena associated with optical and electronic properties of chiral nanostructures and facilitate their applications in biology as well as other areas. Here, we report that covalent attachment of l/d-cysteine moieties to the edges of graphene quantum dots (GQDs) leads to their helical buckling due to chiral interactions at the "crowded" edges. Circular dichroism (CD) spectra of the GQDs revealed bands at ca. 210-220 and 250-265 nm that changed their signs for different chirality of the cysteine edge ligands. The high-energy chiroptical peaks at 210-220 nm correspond to the hybridized molecular orbitals involving the chiral center of amino acids and atoms of graphene edges. Diverse experimental and modeling data, including density functional theory calculations of CD spectra with probabilistic distribution of GQD isomers, indicate that the band at 250-265 nm originates from the three-dimensional twisting of the graphene sheet and can be attributed to the chiral excitonic transitions. The positive and negative low-energy CD bands correspond to the left and right helicity of GQDs, respectively. Exposure of liver HepG2 cells to L/D-GQDs reveals their general biocompatibility and a noticeable difference in the toxicity of the stereoisomers. Molecular dynamics simulations demonstrated that d-GQDs have a stronger tendency to accumulate within the cellular membrane than L-GQDs. Emergence of nanoscale chirality in GQDs decorated with biomolecules is expected to be a general stereochemical phenomenon for flexible sheets of nanomaterials.

  6. Energetics of Nanomaterials

    SciTech Connect

    Alexandra Navrotsky; Brian Woodfield; Juliana Boerio-Goates; Frances Hellman

    2005-01-28

    This project, "Energetics of Nanomaterials," represents a three-year collaboration among Alexandra Navrotsky (UC Davis), Brian Woodfield and Juliana Boerio-Goates (BYU), and Frances Hellman (UC Berkeley). It's purpose has been to explore the differences between bulk materials, nanoparticles, and thin films in term of their thermodynamic properties, with an emphasis on heat capaacities and entropies, as well as enthalpies. the three groups have brought very different expertise and capabilities to the project. Navrotsky is a solid-state chemist and geochemist, with a unique Thermochemistry Facility emphasizing enthalpy of formation measurements by high temperature oxide melt and room temperatue acid solution calorimetry. Boerio-Goates and Woodfield are calorimetry. Hellman is a physicist with expertise in magnetism and heat capacity measurements using microscale "detector on a chip" calorimetric technology that she pioneered. The overarching question of our work is "How does the free energy play out in nanoparticles?", or "How do differences in free energy affect overall nanoparticle behavior?" Because the free energy represents the temperature-dependent balance between the enthalpy of a system and its entropy, there are two separate, but related, components to the experimental investigations: Solution calorimetric measurements provide the energetics and two types of heat capacity measurements the entropy. We use materials that are well characterized in other ways (structurally, magnetically, and chemically), and samples are shared across the collaboration.

  7. Vascular Distribution of Nanomaterials

    PubMed Central

    Stapleton, Phoebe A.; Nurkiewicz, Timothy R.

    2014-01-01

    Once considered primarily occupational, novel nanotechnology innovation and application has led to widespread domestic use and intentional biomedical exposures. With these exciting advances, the breadth and depth of toxicological considerations must also be expanded. The vascular system interacts with every tissue in the body, striving to homeostasis. Engineered nanomaterials (ENM) have been reported to distribute in many different organs and tissues. However, these observations have tended to use approaches requiring tissue homogenization and/or gross organ analyses. These techniques, while effective in establishing presence, preclude an exact determination of where ENM are deposited within a tissue. It is necessary to identify this exact distribution and deposition of ENM throughout the cardiovascular system, with respect to vascular hemodynamics and in vivo/ in vitro ENM modifications taken into account if nanotechnology is to achieve its full potential. Distinct levels of the vasculature will first be described as individual compartments. Then the vasculature will be considered as a whole. These unique compartments and biophysical conditions will be discussed in terms of their propensity to favor ENM deposition. Understanding levels of the vasculature will also be discussed. Ultimately, future studies must verify the mechanisms speculated on and presented herein. PMID:24777845

  8. Structure of graphene oxide dispersed with ZnO nanoparticles

    SciTech Connect

    Yadav, Rishikesh Pandey, Devendra K.; Khare, P. S.

    2014-10-15

    Graphene has been proposed as a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal and mechanical properties for many applications. In present work a process of dispersion of graphene oxide with ZnO nanoparticles in ethanol solution with different pH values, have been studied. Samples have been characterized by XRD, SEM, PL, UV-visible spectroscopy and particles size measurement. The results analysis indicates overall improved emission spectrum. It has been observed that the average diameter of RGO (Reduced Graphene Oxide) decreases in presence of ZnO nanoparticles from 3.8μm to 0.41μm.

  9. Mass spectrometry imaging reveals the sub-organ distribution of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Chen, Suming; Xiong, Caiqiao; Liu, Huihui; Wan, Qiongqiong; Hou, Jian; He, Qing; Badu-Tawiah, Abraham; Nie, Zongxiu

    2015-02-01

    Label and label-free methods to image carbon-based nanomaterials exist. However, label-based approaches are limited by the risk of tag detachment over time, and label-free spectroscopic methods have slow imaging speeds, weak photoluminescence signals and strong backgrounds. Here, we present a label-free mass spectrometry imaging method to detect carbon nanotubes, graphene oxide and carbon nanodots in mice. The large molecular weights of nanoparticles are difficult to detect using conventional mass spectrometers, but our method overcomes this problem by using the intrinsic carbon cluster fingerprint signal of the nanomaterials. We mapped and quantified the sub-organ distribution of the nanomaterials in mice. Our results showed that most carbon nanotubes and nanodots were found in the outer parenchyma of the kidney, and all three materials were seen in the red pulp of the spleen. The highest concentrations of nanotubes in the spleen were found within the marginal zone.

  10. Radio-graphene in Theranostic Perspectives.

    PubMed

    Hwang, Do Won

    2017-03-01

    Owing to its unique physicochemical properties such as high surface area, notable biocompatibility, robust mechanical strength, high thermal conductivity, and ease of functionalization, 2D-layered graphene has received tremendous attention as a futuristic nanomaterial and its-associated research has been rapidly evolving in a variety of fields. With the remarkable advances of graphene especially in the biomedical realm, in vivo evaluation techniques to examine in vivo behavior of graphene are largely demanded under the hope of clinical translation. Many different types of drugs such as the antisense oligomer and chemotherapeutics require optimal delivery conveyor and graphene is now recognized as a suitable candidate due to its simple and high drug loading property. Termed as 'radio-graphene', radioisotope-labeled graphene approach was recently harnessed in the realm of biomedicine including cancer diagnosis and therapy, contributing to the acquisition of in vivo information for targeted drug delivery. In this review, we highlight current examples for bioapplication of radiolabeled graphene with brief perspectives on future strategies in its extensive bio- or clinical applications.

  11. Nucleic acid functionalized graphene for biosensing.

    PubMed

    Bonanni, Alessandra; Ambrosi, Adriano; Pumera, Martin

    2012-02-06

    There is immense demand for complex nanoarchitectures based on graphene nanostructures in the fields of biosensing or nanoelectronics. DNA molecules represent the most versatile and programmable recognition element and can provide a unique massive parallel assembly strategy with graphene nanomaterials. Here we demonstrate a facile strategy for covalent linking of single stranded DNA (ssDNA) to graphene using carbodiimide chemistry and apply it to genosensing. Since graphenes can be prepared by different methods and can contain various oxygen containing groups, we thoroughly investigated the utility of four different chemically modified graphenes for functionalization by ssDNA. The materials were characterized in detail and the different DNA functionalized graphene platforms were then employed for the detection of DNA hybridization and DNA polymorphism by using impedimetric methods. We believe that our findings are very important for the development of novel devices that can be used as alternatives to classical techniques for sensitive and fast DNA analysis. In addition, covalent functionalization of graphene with ssDNA is expected to have broad implications, from biosensing to nanoelectronics and directed, DNA programmable, self-assembly.

  12. Harvesting energy from water flow over graphene?

    PubMed

    Yin, Jun; Zhang, Zhuhua; Li, Xuemei; Zhou, Jianxin; Guo, Wanlin

    2012-03-14

    It is reported excitingly in a previous letter (Nano Lett. 2011, 11, 3123) that a small piece of graphene sheet about 30 × 16 μm(2) immersed in flowing water with 0.6 M hydrochloric acid can produce voltage ~20 mV. Here we find that no measurable voltage can be induced by the flow over mono-, bi- and trilayered graphene samples of ~1 × 1.5 cm(2) in size in the same solution once the electrodes on graphene are isolated from interacting with the solution, mainly because the H(3)O(+) cations in the water adsorb onto graphene by strong covalent bonds as revealed by our first-principles calculations. When both the graphene and its metal electrodes are exposed to the solution as in the previous work, water flow over the graphene-electrode system can induce voltages from a few to over a hundred millivolts. In this situation, the graphene mainly behaves as a load connecting between the electrodes. Therefore, the harvested energy is not from the immersed carbon nanomaterials themselves in ionic water flow but dominated by the exposed electrodes.

  13. Physicochemical characteristics of pristine and functionalized graphene.

    PubMed

    Bourdo, Shawn E; Al Faouri, Radwan; Sleezer, Robert; Nima, Zeid A; Lafont, Andersen; Chhetri, Bijay P; Benamara, Mourad; Martin, Betty; Salamo, Gregory J; Biris, Alexandru S

    2017-11-01

    Graphene-based nanomaterials have received significant attention in the last decade due to their interesting properties. Its electrical and thermal conductivity and strength make graphene well suited for a variety of applications, particularly for use as a composite material in plastics. Furthermore, much work is taking place to utilize graphene as a biomaterial for uses such as drug delivery and tissue regeneration scaffolds. Owing to the rapid progress of graphene and its potential in many marketplaces, the potential toxicity of these materials has garnered attention. Graphene, while simple in its purest form, can have many different chemical and physical properties. In this paper, we describe our toxicity evaluation of pristine graphene and a functionalized graphene sample that has been oxidized for enhanced hydrophilicity, which was synthesized from the pristine sample. The samples were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, thermogravimetric analysis, zeta-potential, atomic force microscopy and electron microscopy. We discuss the disagreement between the size of imaged samples analyzed by atomic force microscopy and by transmission electron microscopy. Furthermore, the samples each exhibit quite different surface chemistry and structure, which directly affects their interaction with aqueous environments and is important to consider when evaluating the toxicity of materials both in vitro and in vivo. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  14. PREFACE: Graphene Graphene

    NASA Astrophysics Data System (ADS)

    Singleton, John; Ferry, David K.

    2009-08-01

    As is now well known, graphene was made in 2004 by the 'simple' expedient of cleaving a single atomic layer from a sample of graphite using a piece of sticky tape [1, 2]. This discovery stimulated a whirlwind of activity; at last, predictions about the unique behaviour of band electrons in a two-dimensional honeycomb lattice made as early as the 1940s could be verified experimentally [1, 2]. Perhaps the most influential result has been the confirmation that the charge carriers in graphene behave in many ways as 'Dirac fermions', mimicing the dynamics of hyper-relativistic electrons, but with 1/300th of the velocity. Another important pairing of prediction and result has been the observation of carrier mobilities that have an unusual (in)dependence on impurity concentration, suggesting applications in high-speed ballistic transistors and even the eventual part replacement of silicon by graphene as the devices on chips become ever smaller [1, 2]. As a result of the considerable and rapid activity in this field, reviews of the properties of graphene have appeared; a good introduction to the early work at a level appropriate to students is given in [1], whilst [2] covers more recent progress at a more advanced level. However, the field is progressing so rapidly that even good reviews become dated by the time they appear in print, and new work and studies are appearing daily. In this issue, we have tried to pull together a group of papers which examine some of these new areas of work in graphene; these range from low-temperature physics to high electric field transport at room temperature [3]. Given the postulated future use of graphene in ultra-small devices, it is no surprise that quantum dots and wires feature heavily in the articles by Peres et al [4], Huang et al [5] and Sun and Xie [6]. Moreover, applications will inevitably involve graphene in contact with other materials and chemical systems, resulting in modifications to its electronic properties. For example

  15. Graphene spintronics.

    PubMed

    Han, Wei; Kawakami, Roland K; Gmitra, Martin; Fabian, Jaroslav

    2014-10-01

    The isolation of graphene has triggered an avalanche of studies into the spin-dependent physical properties of this material and of graphene-based spintronic devices. Here, we review the experimental and theoretical state-of-art concerning spin injection and transport, defect-induced magnetic moments, spin-orbit coupling and spin relaxation in graphene. Future research in graphene spintronics will need to address the development of applications such as spin transistors and spin logic devices, as well as exotic physical properties including topological states and proximity-induced phenomena in graphene and other two-dimensional materials.

  16. Carbon nanomaterials: Biologically active fullerene derivatives.

    PubMed

    Bogdanović, Gordana; Djordjević, Aleksandar

    2016-01-01

    Since their discovery, fullerenes, carbon nanotubes, and graphene attract significant attention of researches in various scientific fields including biomedicine. Nano-scale size and a possibility for diverse surface modifications allow carbon nanoallotropes to become an indispensable nanostructured material in nanotechnologies, including nanomedicine. Manipulation of surface chemistry has created diverse populations of water-soluble derivatives of fullerenes, which exhibit different behaviors. Both non-derivatized and derivatized fullerenes show various biological activities. Cellular processes that underline their toxicity are oxidative, genotoxic, and cytotoxic responses.The antioxidant/cytoprotective properties of fullerenes and derivatives have been considered in the prevention of organ oxidative damage and treatment. The same unique physiochemical properties of nanomaterials may also be associated with potential health hazards. Non-biodegradability and toxicity of carbon nanoparticles still remain a great concern in the area of biomedical application. In this review, we report on basic physical and chemical properties of carbon nano-clusters--fullerenes, nanotubes, and grapheme--their specificities, activities, and potential application in biological systems. Special emphasis is given to our most important results obtained in vitro and in vivo using polyhydroxylated fullerene derivative C₆₀(OH)₂₄.

  17. Crown ethers in graphene.

    PubMed

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I; Gallego, Nidia C; Pantelides, Sokrates T; Pennycook, Stephen J; Moyer, Bruce A; Chisholm, Matthew F

    2014-11-13

    Crown ethers are at their most basic level rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted attention for their ability to selectively incorporate various atoms or molecules within the cavity formed by the ring. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity. Here we present atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar. First-principles calculations show that the close similarity of the structures should also extend to their selectivity towards specific metal cations. Crown ethers in graphene offer a simple environment that can be systematically tested and modelled. Thus, we expect that our finding will introduce a new wave of investigations and applications of chemically functionalized graphene.

  18. Graphene transistors.

    PubMed

    Schwierz, Frank

    2010-07-01

    Graphene has changed from being the exclusive domain of condensed-matter physicists to being explored by those in the electron-device community. In particular, graphene-based transistors have developed rapidly and are now considered an option for post-silicon electronics. However, many details about the potential performance of graphene transistors in real applications remain unclear. Here I review the properties of graphene that are relevant to electron devices, discuss the trade-offs among these properties and examine their effects on the performance of graphene transistors in both logic and radiofrequency applications. I conclude that the excellent mobility of graphene may not, as is often assumed, be its most compelling feature from a device perspective. Rather, it may be the possibility of making devices with channels that are extremely thin that will allow graphene field-effect transistors to be scaled to shorter channel lengths and higher speeds without encountering the adverse short-channel effects that restrict the performance of existing devices. Outstanding challenges for graphene transistors include opening a sizeable and well-defined bandgap in graphene, making large-area graphene transistors that operate in the current-saturation regime and fabricating graphene nanoribbons with well-defined widths and clean edges.

  19. Graphene Oxide as Mine of Knowledge: Using Graphene Oxide to Teach Undergraduate Students Core Chemistry and Nanotechnology Concepts

    ERIC Educational Resources Information Center

    Kondratowicz, Izabela; Z?elechowska, Kamila

    2017-01-01

    The aim of this laboratory experiment is to utilize graphene oxide (GO) material to introduce undergraduate students to many well-known concepts of general chemistry. GO is a new nanomaterial that has generated worldwide interest and can be easily produced in every well-equipped undergraduate chemical laboratory. An in-depth examination of GO…

  20. Carbon Nanomaterials Based Electrochemical Sensors/Biosensors for the Sensitive Detection of Pharmaceutical and Biological Compounds.

    PubMed

    Adhikari, Bal-Ram; Govindhan, Maduraiveeran; Chen, Aicheng

    2015-09-04

    Electrochemical sensors and biosensors have attracted considerable attention for the sensitive detection of a variety of biological and pharmaceutical compounds. Since the discovery of carbon-based nanomaterials, including carbon nanotubes, C60 and graphene, they have garnered tremendous interest for their potential in the design of high-performance electrochemical sensor platforms due to their exceptional thermal, mechanical, electronic, and catalytic properties. Carbon nanomaterial-based electrochemical sensors have been employed for the detection of various analytes with rapid electron transfer kinetics. This feature article focuses on the recent design and use of carbon nanomaterials, primarily single-walled carbon nanotubes (SWCNTs), reduced graphene oxide (rGO), SWCNTs-rGO, Au nanoparticle-rGO nanocomposites, and buckypaper as sensing materials for the electrochemical detection of some representative biological and pharmaceutical compounds such as methylglyoxal, acetaminophen, valacyclovir, β-nicotinamide adenine dinucleotide hydrate (NADH), and glucose. Furthermore, the electrochemical performance of SWCNTs, rGO, and SWCNT-rGO for the detection of acetaminophen and valacyclovir was comparatively studied, revealing that SWCNT-rGO nanocomposites possess excellent electrocatalytic activity in comparison to individual SWCNT and rGO platforms. The sensitive, reliable and rapid analysis of critical disease biomarkers and globally emerging pharmaceutical compounds at carbon nanomaterials based electrochemical sensor platforms may enable an extensive range of applications in preemptive medical diagnostics.

  1. Structural perturbations on huntingtin N17 domain during its folding on 2D-nanomaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Leili; Feng, Mei; Zhou, Ruhong; Luan, Binquan

    2017-09-01

    A globular protein’s folded structure in its physiological environment is largely determined by its amino acid sequence. Recently, newly discovered transformer proteins as well as intrinsically disordered proteins may adopt the folding-upon-binding mechanism where their secondary structures are highly dependent on their binding partners. Due to the various applications of nanomaterials in biological sensors and potential wearable devices, it is important to discover possible conformational changes of proteins on nanomaterials. Here, through molecular dynamics simulations, we show that the first 17 residues of the huntingtin protein (HTT-N17) exhibit appreciable differences during its folding on 2D-nanomaterials, such as graphene and MoS2 nanosheets. Namely, the protein is disordered on the graphene surface but is helical on the MoS2 surface. Despite that the amphiphilic environment at the nanosheet-water interface promotes the folding of the amphipathic proteins (such as HTT-N17), competitions between protein-nanosheet and intra-protein interactions yield very different protein conformations. Therefore, as engineered binding partners, nanomaterials might significantly affect the structures of adsorbed proteins.

  2. Structural perturbations on huntingtin N17 domain during its folding on 2D-nanomaterials.

    PubMed

    Zhang, Leili; Feng, Mei; Zhou, Ruhong; Luan, Binquan

    2017-09-01

    A globular protein's folded structure in its physiological environment is largely determined by its amino acid sequence. Recently, newly discovered transformer proteins as well as intrinsically disordered proteins may adopt the folding-upon-binding mechanism where their secondary structures are highly dependent on their binding partners. Due to the various applications of nanomaterials in biological sensors and potential wearable devices, it is important to discover possible conformational changes of proteins on nanomaterials. Here, through molecular dynamics simulations, we show that the first 17 residues of the huntingtin protein (HTT-N17) exhibit appreciable differences during its folding on 2D-nanomaterials, such as graphene and MoS2 nanosheets. Namely, the protein is disordered on the graphene surface but is helical on the MoS2 surface. Despite that the amphiphilic environment at the nanosheet-water interface promotes the folding of the amphipathic proteins (such as HTT-N17), competitions between protein-nanosheet and intra-protein interactions yield very different protein conformations. Therefore, as engineered binding partners, nanomaterials might significantly affect the structures of adsorbed proteins.

  3. Carbon Nanomaterials Based Electrochemical Sensors/Biosensors for the Sensitive Detection of Pharmaceutical and Biological Compounds

    PubMed Central

    Adhikari, Bal-Ram; Govindhan, Maduraiveeran; Chen, Aicheng

    2015-01-01

    Electrochemical sensors and biosensors have attracted considerable attention for the sensitive detection of a variety of biological and pharmaceutical compounds. Since the discovery of carbon-based nanomaterials, including carbon nanotubes, C60 and graphene, they have garnered tremendous interest for their potential in the design of high-performance electrochemical sensor platforms due to their exceptional thermal, mechanical, electronic, and catalytic properties. Carbon nanomaterial-based electrochemical sensors have been employed for the detection of various analytes with rapid electron transfer kinetics. This feature article focuses on the recent design and use of carbon nanomaterials, primarily single-walled carbon nanotubes (SWCNTs), reduced graphene oxide (rGO), SWCNTs-rGO, Au nanoparticle-rGO nanocomposites, and buckypaper as sensing materials for the electrochemical detection of some representative biological and pharmaceutical compounds such as methylglyoxal, acetaminophen, valacyclovir, β-nicotinamide adenine dinucleotide hydrate (NADH), and glucose. Furthermore, the electrochemical performance of SWCNTs, rGO, and SWCNT-rGO for the detection of acetaminophen and valacyclovir was comparatively studied, revealing that SWCNT-rGO nanocomposites possess excellent electrocatalytic activity in comparison to individual SWCNT and rGO platforms. The sensitive, reliable and rapid analysis of critical disease biomarkers and globally emerging pharmaceutical compounds at carbon nanomaterials based electrochemical sensor platforms may enable an extensive range of applications in preemptive medical diagnostics. PMID:26404304

  4. Hydrophilic graphene surface prepared by electrochemically reduced micellar graphene oxide as a platform for electrochemical sensor.

    PubMed

    Akkarachanchainon, Nontapol; Rattanawaleedirojn, Pranee; Chailapakul, Orawon; Rodthongkum, Nadnudda

    2017-04-01

    Graphene is one of the promising hydrophobic carbon-based nanomaterials used for electrode modification in electrochemical sensor. However, hydrophobicity of graphene makes it incompatible with aqueous electrolyte solution, leading to significant impediment to the electron transfer process. Here, we aim to alter graphene property to be hydrophilicity by using an electrochemically reduced micellar graphene oxide for electrode surface modification. Then, this system was applied for the simultaneous determination of toxic pesticides (e.g. carbofuran and carbendazim). Interestingly, the modified electrode offers an improved electrochemical sensitivity, verified by a drastic increase in current signal of carbofuran (4 times) and carbendazim (12 times) compared to an unmodified electrode. Under the optimal conditions, low detection limits of carbofuran and carbendazim were found to be 10µgL(-1) and 5µgL(-1), respectively. Ultimately, this system was successfully applied for the sensitive and simultaneous determination of carbofuran and carbendazim residues in various agricultural products.

  5. Synthesis and Functionalization of 3D Nano-graphene Materials: Graphene Aerogels and Graphene Macro Assemblies.

    PubMed

    Campbell, Patrick G; Worsley, Marcus A; Hiszpanski, Anna M; Baumann, Theodore F; Biener, Juergen

    2015-11-05

    Efforts to assemble graphene into three-dimensional monolithic structures have been hampered by the high cost and poor processability of graphene. Additionally, most reported graphene assemblies are held together through physical interactions (e.g., van der Waals forces) rather than chemical bonds, which limit their mechanical strength and conductivity. This video method details recently developed strategies to fabricate mass-producible, graphene-based bulk materials derived from either polymer foams or single layer graphene oxide. These materials consist primarily of individual graphene sheets connected through covalently bound carbon linkers. They maintain the favorable properties of graphene such as high surface area and high electrical and thermal conductivity, combined with tunable pore morphology and exceptional mechanical strength and elasticity. This flexible synthetic method can be extended to the fabrication of polymer/carbon nanotube (CNT) and polymer/graphene oxide (GO) composite materials. Furthermore, additional post-synthetic functionalization with anthraquinone is described, which enables a dramatic increase in charge storage performance in supercapacitor applications.

  6. Editorial: Functional nanomaterials for energy applications

    SciTech Connect

    Devan, Rupesh S.; Ma, Yuan -Ron; Kim, Jin -Hyeok; Bhattacharya, Raghu N.; Ghosh, Kartik C.

    2015-02-16

    In order to leap forward from the energy crisis issues and improve lifestyle, we all are looking positively toward nanomaterials or nanostructures. Thus, the exploration of new features of both typical and novel materials at the nanoscale level is playing important role in the development of innovative and improved energy technologies that have the capability of conserve/convert energy at large extend. By tailoring the surface morphology of materials in its nanoforms, the functional properties can be significantly adapted and specifically combined to produce highly potent multifunctional materials for conversion, storage, and consumption of energy in various forms. The papers selected for this special issue represent a good panel for addressing various energy applications including solar cell, fuel cells, nanofluid twisters, and gas sensors. Of course, the selected topic and the papers are not an exhaustive representation of the utilization of functional nanomaterials for energy applications. Nevertheless, they represent the rich and many-facet knowledge, which we have the pleasure of sharing with the readers.

  7. Editorial: Functional nanomaterials for energy applications

    DOE PAGES

    Devan, Rupesh S.; Ma, Yuan -Ron; Kim, Jin -Hyeok; ...

    2015-02-16

    In order to leap forward from the energy crisis issues and improve lifestyle, we all are looking positively toward nanomaterials or nanostructures. Thus, the exploration of new features of both typical and novel materials at the nanoscale level is playing important role in the development of innovative and improved energy technologies that have the capability of conserve/convert energy at large extend. By tailoring the surface morphology of materials in its nanoforms, the functional properties can be significantly adapted and specifically combined to produce highly potent multifunctional materials for conversion, storage, and consumption of energy in various forms. The papers selectedmore » for this special issue represent a good panel for addressing various energy applications including solar cell, fuel cells, nanofluid twisters, and gas sensors. Of course, the selected topic and the papers are not an exhaustive representation of the utilization of functional nanomaterials for energy applications. Nevertheless, they represent the rich and many-facet knowledge, which we have the pleasure of sharing with the readers.« less

  8. NEIMiner: nanomaterial environmental impact data miner.

    PubMed

    Tang, Kaizhi; Liu, Xiong; Harper, Stacey L; Steevens, Jeffery A; Xu, Roger

    2013-01-01

    As more engineered nanomaterials (eNM) are developed for a wide range of applications, it is crucial to minimize any unintended environmental impacts resulting from the application of eNM. To realize this vision, industry and policymakers must base risk management decisions on sound scientific information about the environmental fate of eNM, their availability to receptor organisms (eg, uptake), and any resultant biological effects (eg, toxicity). To address this critical need, we developed a model-driven, data mining system called NEIMiner, to study nanomaterial environmental impact (NEI). NEIMiner consists of four components: NEI modeling framework, data integration, data management and access, and model building. The NEI modeling framework defines the scope of NEI modeling and the strategy of integrating NEI models to form a layered, comprehensive predictability. The data integration layer brings together heterogeneous data sources related to NEI via automatic web services and web scraping technologies. The data management and access layer reuses and extends a popular content management system (CMS), Drupal, and consists of modules that model the complex data structure for NEI-related bibliography and characterization data. The model building layer provides an advanced analysis capability for NEI data. Together, these components provide significant value to the process of aggregating and analyzing large-scale distributed NEI data. A prototype of the NEIMiner system is available at http://neiminer.i-a-i.com/.

  9. NEIMiner: nanomaterial environmental impact data miner

    PubMed Central

    Tang, Kaizhi; Liu, Xiong; Harper, Stacey L; Steevens, Jeffery A; Xu, Roger

    2013-01-01

    As more engineered nanomaterials (eNM) are developed for a wide range of applications, it is crucial to minimize any unintended environmental impacts resulting from the application of eNM. To realize this vision, industry and policymakers must base risk management decisions on sound scientific information about the environmental fate of eNM, their availability to receptor organisms (eg, uptake), and any resultant biological effects (eg, toxicity). To address this critical need, we developed a model-driven, data mining system called NEIMiner, to study nanomaterial environmental impact (NEI). NEIMiner consists of four components: NEI modeling framework, data integration, data management and access, and model building. The NEI modeling framework defines the scope of NEI modeling and the strategy of integrating NEI models to form a layered, comprehensive predictability. The data integration layer brings together heterogeneous data sources related to NEI via automatic web services and web scraping technologies. The data management and access layer reuses and extends a popular content management system (CMS), Drupal, and consists of modules that model the complex data structure for NEI-related bibliography and characterization data. The model building layer provides an advanced analysis capability for NEI data. Together, these components provide significant value to the process of aggregating and analyzing large-scale distributed NEI data. A prototype of the NEIMiner system is available at http://neiminer.i-a-i.com/. PMID:24098076

  10. Photoinduced toxicity of engineered nanomaterials

    NASA Astrophysics Data System (ADS)

    Jones, Philip Scott

    Engineered nanomaterials including metal, metal oxide and carbon based nanomaterials are extensively used in a wide variety of applications to the extent that their presence in the environment is expected to increase dramatically over the next century. These nanomaterials may be photodegraded by solar radiation and thereby release metal ions into the environment that can produce cytotoxic and genotoxic effects. Photoinduced toxicity experiments are performed exposing human lung epithelial carcinoma cells [H1650] to engineered semiconductor nanoparticles such as CdSe quantum dots and ZnO nanoparticles after exposure to 3, 6, and 9 hours of solar simulated radiation. Cytotoxicity and genotoxicity of the metal ions are evaluated using ZnSO4 and CdCl2 solutions for the MTT assay and Comet assay respectively. The objective of the dissertation is to obtain quantitative information about the environmental transformation of engineered nanomaterials and their mechanism of toxicity. This information is critical for addressing the environmental health and safety risks of engineered nanomaterials to workers, consumers and the environment.

  11. Health hazards associated with nanomaterials.

    PubMed

    Pattan, Gurulingappa; Kaul, Gautam

    2014-07-01

    Nanotechnology is a major scientific and economic growth area and presents a variety of hazards for human health and environment. It is widely believed that engineered nanomaterials will be increasingly used in biomedical applications (as therapeutics and as diagnostic tools). However, before these novel materials can be safely applied in a clinical setting, their toxicity needs to be carefully assessed. Nanoscale materials often behave different from the materials with a larger structure, even when the basic material is same. Many mammals get exposed to these nanomaterials, which can reach almost every cell of the mammalian body, causing the cells to respond against nanoparticles (NPs) resulting in cytotoxicity and/or genotoxicity. The important key to understand the toxicity of nanomaterials is that their minute size, smaller than cellular organelles, allows them to penetrate the basic biological structures, disrupting their normal function. There is a wealth of evidence for the noxious and harmful effects of engineered NPs as well as other nanomaterials. The rapid commercialization of nanotechnology field requires thoughtful, attentive environmental, animal and human health safety research and should be an open discussion for broader societal impacts and urgent toxicological oversight action. While 'nanotoxicity' is a relatively new concept to science, this comprehensive review focuses on the nanomaterials exposure through the skin, respiratory tract, and gastrointestinal tract and their mechanism of toxicity and effect on various organs of the body.

  12. Strain Relaxation in CVD Graphene: Wrinkling with Shear Lag.

    PubMed

    Bronsgeest, Merijntje S; Bendiab, Nedjma; Mathur, Shashank; Kimouche, Amina; Johnson, Harley T; Coraux, Johann; Pochet, Pascal

    2015-08-12

    We measure uniaxial strain fields in the vicinity of edges and wrinkles in graphene prepared by chemical vapor deposition (CVD), by combining microscopy techniques and local vibrational characterization. These strain fields have magnitudes of several tenths of a percent and extend across micrometer distances. The nonlinear shear-lag model remarkably captures these strain fields in terms of the graphene-substrate interaction and provides a complete understanding of strain-relieving wrinkles in graphene for any level of graphene-substrate coherency.

  13. The structural development of primary cultured hippocampal neurons on a graphene substrate.

    PubMed

    He, Zuhong; Zhang, Shasha; Song, Qin; Li, Wenyan; Liu, Dong; Li, Huawei; Tang, Mingliang; Chai, Renjie

    2016-10-01

    The potential of graphene-based nanomaterials as a neural interfacing material for neural repair and regeneration remains poorly understood. In the present study, the response to the graphene substrate by neurons was determined in a hippocampal culture model. The results revealed the growth and maturation of hippocampal cultures on graphene substrates were significantly improved compared to the commercial control. In details, graphene promoted growth cone growth and microtubule formation inside filopodia 24h after seeding as evidenced by a higher average number of filopodia emerging from growth cones, a longer average length of filopodia, and a larger growth cone area. Graphene also significantly boosted neurite sprouting and outgrowth. The dendritic length, the number of branch points, and the dendritic complex index were significantly improved on the graphene substrate during culture. Moreover, the spine density was enhanced and the maturation of dendritic spines from thin to stubby spines was significantly promoted on graphene at 21 days after seeding. Lastly, graphene significantly elevated the synapse density and synaptic activity in the hippocampal cultures. The present study highlights graphene's potential as a neural interfacing material for neural repair and regeneration and sheds light on the future biomedical applications of graphene-based nanomaterials. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Graphene in high magnetic fields

    NASA Astrophysics Data System (ADS)

    Orlita, Milan; Escoffier, Walter; Plochocka, Paulina; Raquet, Bertrand; Zeitler, Uli

    2013-01-01

    Carbon-based nano-materials, such as graphene and carbon nanotubes, represent a fascinating research area aiming at exploring their remarkable physical and electronic properties. These materials not only constitute a playground for physicists, they are also very promising for practical applications and are envisioned as elementary bricks of the future of the nano-electronics. As for graphene, its potential already lies in the domain of opto-electronics where its unique electronic and optical properties can be fully exploited. Indeed, recent technological advances have demonstrated its effectiveness in the fabrication of solar cells and ultra-fast lasers, as well as touch-screens and sensitive photo-detectors. Although the photo-voltaic technology is now dominated by silicon-based devices, the use of graphene could very well provide higher efficiency. However, before the applied research to take place, one must first demonstrates the operativeness of carbon-based nano-materials, and this is where the fundamental research comes into play. In this context, the use of magnetic field has been proven extremely useful for addressing their fundamental properties as it provides an external and adjustable parameter which drastically modifies their electronic band structure. In order to induce some significant changes, very high magnetic fields are required and can be provided using both DC and pulsed technology, depending of the experimental constraints. In this article, we review some of the challenging experiments on single nano-objects performed in high magnetic and low temperature. We shall mainly focus on the high-field magneto-optical and magneto-transport experiments which provided comprehensive understanding of the peculiar Landau level quantization of the Dirac-type charge carriers in graphene and thin graphite.

  15. Graphene oxide: a carrier for pharmaceuticals and a scaffold for cell interactions.

    PubMed

    Durán, Nelson; Martinez, Diego Stéfani T; Silveira, Camila P; Durán, Marcela; de Moraes, Ana C M; Simões, Mateus B; Alves, Oswaldo L; Fávaro, Wagner J

    2015-01-01

    During the last ten years, graphene oxide has been explored in many applications due to its remarkable electroconductivity, thermal properties and mobility of charge carriers, among other properties. As discussed in this review, the literature suggests that a total characterization of graphene oxide must be conducted because oxidation debris (synthesis impurities) present in the graphene oxides could act as a graphene oxide surfactant, stabilizing aqueous dispersions. It is also important to note that the structure models of graphene oxide need to be revisited because of significant implications for its chemical composition and its direct covalent functionalization. Another aspect that is discussed is the need to consider graphene oxide surface chemistry. The hemolysis assay is recommended as a reliable test for the preliminary assessment of graphene oxide toxicity, biocompatibility and cell membrane interaction. More recently, graphene oxide has been extensively explored for drug delivery applications. An important increase in research efforts in this emerging field is clearly represented by the hundreds of related publications per year, including some reviews. Many studies have been performed to explore the graphene oxide properties that enable it to deliver more than one activity simultaneously and to combine multidrug systems with photothermal therapy, indicating that graphene oxide is an attractive tool to overcome hurdles in cancer therapies. Some strategic aspects of the application of these materials in cancer treatment are also discussed. In vitro studies have indicated that graphene oxide can also promote stem cell adhesion, growth and differentiation, and this review discusses the recent and pertinent findings regarding graphene oxide as a valuable nanomaterial for stem cell research in medicine. The protein corona is a key concept in nanomedicine and nanotoxicology because it provides a biomolecular identity for nanomaterials in a biological environment

  16. Cellular Stress Responses Elicited by Engineered Nanomaterials

    EPA Science Inventory

    Engineered nanomaterials are being incorporated continuously into consumer products, resulting in increased human exposures. The study of engineered nanomaterials has focused largely on oxidative stress and inflammation endpoints without further investigation of underlying pathwa...

  17. Engineered Nanomaterials Elicit Cellular Stress Responses

    EPA Science Inventory

    Engineered nanomaterials are being developed continuously and incorporated into consumer products, resulting in increased human exposures. The study of engineered nanomaterials has focused largely on toxicity endpoints without further investigating potential mechanisms or pathway...

  18. NANOMATERIALS, NANOTECHNOLOGY: APPLICATIONS, CONSUMER PRODUCTS, AND BENEFITS

    EPA Science Inventory

    Nanotechnology is a platform technology that is finding more and more applications daily. Today over 600 consumer products are available globally that utilize nanomaterials. This chapter explores the use of nanomaterials and nanotechnology in three areas, namely Medicine, Environ...

  19. Engineered Nanomaterials Elicit Cellular Stress Responses

    EPA Science Inventory

    Engineered nanomaterials are being developed continuously and incorporated into consumer products, resulting in increased human exposures. The study of engineered nanomaterials has focused largely on toxicity endpoints without further investigating potential mechanisms or pathway...

  20. How Do Enzymes 'Meet' Nanoparticles and Nanomaterials?

    PubMed

    Chen, Ming; Zeng, Guangming; Xu, Piao; Lai, Cui; Tang, Lin

    2017-09-13

    Enzymes are fundamental biological catalysts responsible for biological regulation and metabolism. The opportunity for enzymes to 'meet' nanoparticles and nanomaterials is rapidly increasing due to growing demands for applications in nanomaterial design, environmental monitoring, biochemical engineering, and biomedicine. Therefore, understanding the nature of nanomaterial-enzyme interactions is becoming important. Since 2014, enzymes have been used to modify, degrade, or make nanoparticles/nanomaterials, while numerous nanoparticles/nanomaterials have been used as materials for enzymatic immobilization and biosensors and as enzyme mimicry. Among the various nanoparticles and nanomaterials, metal nanoparticles and carbon nanomaterials have received extensive attention due to their fascinating properties. This review provides an overview about how enzymes meet nanoparticles and nanomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. NANOMATERIALS, NANOTECHNOLOGY: APPLICATIONS, CONSUMER PRODUCTS, AND BENEFITS

    EPA Science Inventory

    Nanotechnology is a platform technology that is finding more and more applications daily. Today over 600 consumer products are available globally that utilize nanomaterials. This chapter explores the use of nanomaterials and nanotechnology in three areas, namely Medicine, Environ...

  2. Cellular Stress Responses Elicited by Engineered Nanomaterials

    EPA Science Inventory

    Engineered nanomaterials are being incorporated continuously into consumer products, resulting in increased human exposures. The study of engineered nanomaterials has focused largely on oxidative stress and inflammation endpoints without further investigation of underlying pathwa...

  3. The nanomaterial toolkit for neuroengineering

    NASA Astrophysics Data System (ADS)

    Shah, Shreyas

    2016-10-01

    There is a growing interest in developing effective tools to better probe the central nervous system (CNS), to understand how it works and to treat neural diseases, injuries and cancer. The intrinsic complexity of the CNS has made this a challenging task for decades. Yet, with the extraordinary recent advances in nanotechnology and nanoscience, there is a general consensus on the immense value and potential of nanoscale tools for engineering neural systems. In this review, an overview of specialized nanomaterials which have proven to be the most effective tools in neuroscience is provided. After a brief background on the prominent challenges in the field, a variety of organic and inorganic-based nanomaterials are described, with particular emphasis on the distinctive properties that make them versatile and highly suitable in the context of the CNS. Building on this robust nano-inspired foundation, the rational design and application of nanomaterials can enable the generation of new methodologies to greatly advance the neuroscience frontier.

  4. Porous substrates filled with nanomaterials

    DOEpatents

    Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.; Stadermann, Michael

    2014-08-19

    A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

  5. Graphene as multi-functional delivery platform in cancer therapy.

    PubMed

    Nejabat, Mojgan; Charbgoo, Fahimeh; Ramezani, Mohammad

    2017-04-03

    The biomedical applications of graphene-based nanomaterials including drug and gene delivery have grown rapidly in the past few years. This is due to its high surface area that results in high cargo loading capacity. It is demonstrated that graphene can improve drug efficacy without increasing the dose of the chemotherapeutic agent in cancer treatment. Considering these valuable benefits of graphene, this review focused on the newest advancements in drug and gene delivery systems using graphene and unveiling advantages and disadvantages of different graphene-based materials in introducing an effective cargo delivery system for cancer therapy. Different approaches for reducing cytotoxic impacts of grapheme oxide and production of biocompatible delivery platform were also reviewed. This article is protected by copyright. All rights reserved.

  6. Competitive Binding of Natural Amphiphiles with Graphene Derivatives

    PubMed Central

    Radic, Slaven; Geitner, Nicholas K.; Podila, Ramakrishna; Käkinen, Aleksandr; Chen, Pengyu; Ke, Pu Chun; Ding, Feng

    2013-01-01

    Understanding the transformation of graphene derivatives by natural amphiphiles is essential for elucidating the biological and environmental implications of this emerging class of engineered nanomaterials. Using rapid discrete-molecular-dynamics simulations, we examined the binding of graphene and graphene oxide with peptides, fatty acids, and cellulose, and complemented our simulations by experimental studies of Raman spectroscopy, FTIR, and UV-Vis spectrophotometry. Specifically, we established a connection between the differential binding and the conformational flexibility, molecular geometry, and hydrocarbon content of the amphiphiles. Importantly, our dynamics simulations revealed a Vroman-like competitive binding of the amphiphiles for the graphene oxide substrate. This study provides a mechanistic basis for addressing the transformation, evolution, transport, biocompatibility, and toxicity of graphene derivatives in living systems and the natural environment. PMID:23881402

  7. Carbon Nanomaterials and DNA: from Molecular Recognition to Applications.

    PubMed

    Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2016-03-15

    DNA is polymorphic. Increasing evidence has indicated that many biologically important processes are related to DNA's conformational transition and assembly states. In particular, noncanonical DNA structures, such as the right-handed A-form, the left-handed Z-form, the triplex, the G-quadruplex, the i-motif, and so forth, have been specific targets for the diagnosis and therapy of human diseases. Meanwhile, they have been widely used in the construction of smart DNA nanomaterials and nanoarchitectures. As rising stars in materials science, the family of carbon nanomaterials (CNMs), including two-dimensional graphene, one-dimensional carbon nanotubes (CNTs), and zero-dimensional graphene or carbon quantum dots (GQDs or CQDs), interact with DNA and are able to regulate the conformational transitions of DNA. The interaction of DNA with CNMs not only opens new opportunities for specific molecular recognition, but it also expands the promising applications of CNMs from materials science to biotechnology and biomedicine. In this Account, we focus on our contributions to the field of interactions between CNMs and DNA in which we have explored their promising applications in nanodevices, sensing, materials synthesis, and biomedicine. For one-dimensional CNTs, two-dimensional graphene, and zero-dimensional GQDs and CQDs, the basic principles, binding modes, and applications of the interactions between CNMs and DNA are reviewed. We aim to give prominence to the important status of CNMs in the field of molecular recognition for DNA. First, we summarized our discovery of the interactions between single-walled carbon nanotubes (SWNTs) with duplex, triplex, and human telomeric i-motif DNA and their interesting applications. For example, SWNTs are the first chemical agents that can selectively stabilize human telomeric i-motif DNA and induce its formation under physiological conditions. On the basis of this principle, two types of nanodevices were designed. One was used for

  8. Receptor-Mediated Endocytosis of Two-Dimensional Nanomaterials Undergoes Flat Vesiculation and Occurs by Revolution and Self-Rotation.

    PubMed

    Mao, Jian; Chen, Pengyu; Liang, Junshi; Guo, Ruohai; Yan, Li-Tang

    2016-01-26

    Two-dimensional nanomaterials, such as graphene and transitional metal dichalcogenide nanosheets, are promising materials for the development of antimicrobial surfaces and the nanocarriers for intracellular therapy. Understanding cell interaction with these emerging materials is an urgently important issue to promoting their wide applications. Experimental studies suggest that two-dimensional nanomaterials enter cells mainly through receptor-mediated endocytosis. However, the detailed molecular mechanisms and kinetic pathways of such processes remain unknown. Here, we combine computer simulations and theoretical derivation of the energy within the system to show that the receptor-mediated transport of two-dimensional nanomaterials, such as graphene nanosheet across model lipid membrane, experiences a flat vesiculation event governed by the receptor density and membrane tension. The graphene nanosheet is found to undergo revolution relative to the membrane and, particularly, unique self-rotation around its normal during membrane wrapping. We derive explicit expressions for the formation of the flat vesiculation, which reveals that the flat vesiculation event can be fundamentally dominated by a dimensionless parameter and a defined relationship determined by complicated energy contributions. The mechanism offers an essential understanding on the cellular internalization and cytotoxicity of the emerging two-dimensional nanomaterials.

  9. One-step synthesis of large-scale graphene film doped with gold nanoparticles at liquid-air interface for electrochemistry and Raman detection applications.

    PubMed

    Zhang, Panpan; Huang, Ying; Lu, Xin; Zhang, Siyu; Li, Jingfeng; Wei, Gang; Su, Zhiqiang

    2014-07-29

    We demonstrated a facile one-step synthesis strategy for the preparation of a large-scale reduced graphene oxide multilayered film doped with gold nanoparticles (RGO/AuNP film) and applied this film as functional nanomaterials for electrochemistry and Raman detection applications. The related applications of the fabricated RGO/AuNP film in electrochemical nonenzymatic H2O2 biosensor, electrochemical oxygen reduction reaction (ORR), and surface-enhanced Raman scattering (SERS) detection were investigated. Electrochemical data indicate that the H2O2 biosensor fabricated by RGO/AuNP film shows a wide linear range, low limitation of detection, high selectivity, and long-term stability. In addition, it was proved that the created RGO/AuNP film also exhibits excellent ORR electrochemical catalysis performance. The created RGO/AuNP film, when serving as SERS biodetection platform, presents outstanding performances in detecting 4-aminothiophenol with an enhancement factor of approximately 5.6 × 10(5) as well as 2-thiouracil sensing with a low concentration to 1 μM. It is expected that this facile strategy for fabricating large-scale graphene film doped with metallic nanoparticles will spark inspirations in preparing functional nanomaterials and further extend their applications in drug delivery, wastewater purification, and bioenergy.

  10. Nanomaterials under high-pressure.

    PubMed

    San-Miguel, Alfonso

    2006-10-01

    The use of high-pressure for the study and elaboration of homogeneous nanostructures is critically reviewed. Size effects, the interaction between nanostructures and guest species or the interaction of the nanosystem with the pressure transmitting medium are emphasized. Phase diagrams and the possibilities opened by the combination of pressure and temperature for the elaboration of new nanomaterials is underlined through the examination of three different systems: nanocrystals, nano-cage materials which include fullerites and group-14 clathrates, and single wall nanotubes. This tutorial review is addressed to scientist seeking an introduction or a panoramic view of the study of nanomaterials under high-pressure.

  11. Exposure monitoring of graphene nanoplatelets manufacturing workplaces.

    PubMed

    Lee, Ji Hyun; Han, Jong Hun; Kim, Jae Hyun; Kim, Boowook; Bello, Dhimiter; Kim, Jin Kwon; Lee, Gun Ho; Sohn, Eun Kyung; Lee, Kyungmin; Ahn, Kangho; Faustman, Elaine M; Yu, Il Je

    2016-01-01

    Graphenes have emerged as a highly promising, two-dimensional engineered nanomaterial that can possibly substitute carbon nanotubes. They are being explored in numerous R&D and industrial applications in laboratories across the globe, leading to possible human and environmental exposures to them. Yet, there are no published data on graphene exposures in occupational settings and no readily available methods for their detection and quantitation exist. This study investigates for the first time the potential exposure of workers and research personnel to graphenes in two research facilities and evaluates the status of the control measures. One facility manufactures graphene using graphite exfoliation and chemical vapor deposition (CVD), while the other facility grows graphene on a copper plate using CVD, which is then transferred to a polyethylene terephthalate (PET) sheet. Graphene exposures and process emissions were investigated for three tasks - CVD growth, exfoliation, and transfer - using a multi-metric approach, which utilizes several direct reading instruments, integrated sampling, and chemical and morphological analysis. Real-time instruments included a dust monitor, condensation particle counter (CPC), nanoparticle surface area monitor, scanning mobility particle sizer, and an aethalometer. Morphologically, graphenes and other nanostructures released from the work process were investigated using a transmission electron microscope (TEM). Graphenes were quantified in airborne respirable samples as elemental carbon via thermo-optical analysis. The mass concentrations of total suspended particulate at Workplaces A and B were very low, and elemental carbon concentrations were mostly below the detection limit, indicating very low exposure to graphene or any other particles. The real-time monitoring, especially the aethalometer, showed a good response to the released black carbon, providing a signature of the graphene released during the opening of the CVD reactor

  12. Transfer matrix theory of monolayer graphene/bilayer graphene heterostructure superlattice

    SciTech Connect

    Wang, Yu

    2014-10-28

    We have formulated a transfer matrix method to investigate electronic properties of graphene heterostructure consisting of monolayer graphene and bilayer counterpart. By evaluating transmission, conductance, and band dispersion, we show that, irrespective of the different carrier chiralities in monolayer graphene and bilayer graphene, superlattice consisting of biased bilayer graphene barrier and monolayer graphene well can mimic the electronic properties of conventional semiconductor superlattice, displaying the extended subbands in the quantum tunneling regime and producing anisotropic minigaps for the classically allowed transport. Due to the lateral confinement, the lowest mode has shifted away from the charge neutral point of monolayer graphene component, opening a sizeable gap in concerned structure. Following the gate-field and geometry modulation, all electronic states and gaps between them can be externally engineered in an electric-controllable strategy.

  13. Biodegradation of Carbon Nanotubes, Graphene, and Their Derivatives.

    PubMed

    Chen, Ming; Qin, Xiaosheng; Zeng, Guangming

    2017-09-01

    Carbon nanotubes (CNTs), graphene (GRA), and their derivatives are promising materials for a wide range of applications such as pollutant removal, enzyme immobilization, bioimaging, biosensors, and drug delivery and are rapidly increasing in use and increasingly mass produced. The biodegradation of carbon nanomaterials by microbes and enzymes is now of great importance for both reducing their toxicity to living organisms and removing them from the environment. Here we review recent progress in the biodegradation field from the point of view of the primary microbes and enzymes that can degrade these nanomaterials, along with experimental and molecular simulation methods for the exploration of nanomaterial degradation. Further efforts should primarily aim toward expanding the repertoire of microbes and enzymes and exploring optimal conditions for the degradation of nanomaterials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. New Insights on the Influence of Organic Co-Contaminants on the Aquatic Toxicology of Carbon Nanomaterials.

    PubMed

    Sanchís, Josep; Olmos, Mar; Vincent, Phil; Farré, Marinella; Barceló, Damià

    2016-01-19

    At present, there is a lack of understanding of the combined ecotoxicity of carbon-based nanomaterials and co-contaminants. In this paper, we report on the toxicity of three carbon nanomaterials (fullerene-soot, multiwall carbon nanotubes, and graphene). Two standardized toxicity bioassays, the immobilization of the invertebrate Daphnia magna and the bioluminescence inhibition of the marine bacteria Vibrio fischeri, have been used. Synergistic and antagonistic effects of binary mixtures composed of fullerene soot and organic co-contaminants as malathion, glyphosate, diuron, triclosan, and nonylphenol were assessed. The isobologram method was used to evaluate the concentrations producing an effect, in comparison to those effects expected by a simple additive approach. In this study, antagonism was the predominant effect. However, synergism was also observed as in the case of D. magna exposed to mixtures of malathion and fullerene soot. D. magna was shown to be the most sensitive assay when carbon nanomaterials were present. Toxicity to D. magna was as follows: fullerene soot > multiwall carbon nanotubes > graphene. These results were proportional to the size of aggregates, smaller aggregates being the most toxic. The vector function of nanomaterials aggregates and the unexpected release inside living organisms was proven for malathion. These results highlight new insights on the risks associated with the release of carbon nanomaterials into the environment.

  15. Influence of carbon-based nanomaterials on lux-bioreporter Escherichia coli.

    PubMed

    Jia, Kun; Marks, Robert S; Ionescu, Rodica E

    2014-08-01

    The cytotoxic effects of carbon-based nanomaterials are evaluated via the induction of luminescent genetically engineered Escherichia coli bacterial cells. Specifically, two engineered E. coli bacteria strains of DPD2794 and TV1061 were incubated with aqueous dispersion of three carbon allotropes (multi-wall carbon nanotubes (MWCNTs), graphene nanosheets and carbon black nanopowders) with different concentrations and the resulting bioluminescence was recorded at 30°C and 25°C, respectively. The corresponding optical density changes of bacterial cells in the presence of various carbon nanomaterials were recorded as well. Based on these results, E. coli DPD2794 bacterial induction responds to a greater degree than E. coli TV1061 bacteria when exposed to various carbon-based nanomaterials. Finally, the surface morphology of E. coli DPD2794 bacteria cells before and after carbon-based nanomaterials treatment was observed using a field emission scanning electron microscope (FESEM), from which morphological changes from the presence of carbon-based nanomaterials were observed and discussed.

  16. Aromatic graphene

    SciTech Connect

    Das, D. K.; Sahoo, S.

    2016-04-13

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  17. Aromatic graphene

    NASA Astrophysics Data System (ADS)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  18. Atomic-scale insights into 1D and 2D nano-materials

    NASA Astrophysics Data System (ADS)

    Bangert, U.; Pierce, W.; Boothroyd, C. B.; Migliorato, M.; Pan, C.-T.; Harvey, A. J.; Kepatsoglou, D. M.; Ramasse, Q. M.

    2015-10-01

    Atomic resolution imaging and narrow-energy spread spectroscopy in aberration corrected (scanning) transmission electron microscopes, in combination with DFT modelling has made it possible to uncover atomic-scale morphology, defect constellations, lattice impurities and ad-atoms in nano-materials, as well as revealing their influence on the surrounding bandstructure. Using atomic-scale imaging, EEL spectroscopy and EFTEM, we address issues beyond the more common investigations of their atomic lattice structure. We focus on the demonstration of (i) ripples in graphene and on effects of (ii) metal ad-atoms as well as of (iii) controllably introduced impurities -via low energy ion implantation- in both, graphene and carbon nanotubes, on the electronic band structure. We demonstrate the creation of a new feature with collective charge carrier behaviour (plasmon) in the UV/vis range in graphene and carbon nanotubes via EEL spectrum imaging and EFTEM, and support this with dielectric theory modelling.

  19. Theory of graphene saturable absorption

    NASA Astrophysics Data System (ADS)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  20. Energetics of Nanomaterials

    SciTech Connect

    Hellman, Frances

    2004-12-13

    This project, ''Energetics of Nanomaterials'', represents a three-year collaboration among Alexandra Navrotsky (University of California at Davis), Brian Woodfield and Juliana Boerio-Goates (Brigham Young University) and Frances Hellman (University of California at San Diego). Its purpose has been to explore the differences between bulk materials, nanoparticles, and thin films in terms of their thermodynamic properties, with an emphasis on heat capacities and entropies, as well as enthalpies. We used our combined experimental techniques to address the following questions: How does energy and entropy depend on particle size and crystal structure? Do entropic differences have their origins in changes in vibrational densities of states or configurational (including surface configuration) effects? Do material preparation and sample geometry, i.e., nanoparticles versus thin films, change these quantities? How do the thermodynamics of magnetic and structural transitions change in nanoparticles and thin films? Are different crystal structures stabilized for a given composition at the nanoscale, and are the responsible factors energetic, entropic, or both? How do adsorption energies (for water and other gases) depend on particle size and crystal structure in the nanoregime? What are the energetics of formation and strain energies in artificially layered thin films? Do the differing structures of grain boundaries in films and nanocomposites alter the energetics of nanoscale materials? Of the several directions we first proposed, we initially concentrated on a few systems: TiO(sub 2), CoO, and CoO-MgO. In these systems, we were able to clearly identify particle size-dependent effects on energy and vibrational entropy, and to separate out the effect of particle size and water content on the enthalpy of formation of the various TiO(sub 2) polymorphs. With CoO, we were able to directly compare nanoparticle films and bulk materials; this comparison is important because films can

  1. Directed Nanoscale Assembly of Graphene Based Materials

    NASA Astrophysics Data System (ADS)

    Kim, Sang Ouk

    Graphene based materials, including fullerene, carbon nanotubes and graphene, are two-dimensional polymeric materials consisting of sp2 hybrid carbons. Those carbon materials have attracted enormous research attention for their outstanding material properties along with molecular scale dimension. The optimized utilization of those materials in various application fields inevitably requires the subtle controllability of their structures and properties. In this presentation, our research achievements associated to directed nanoscale assembly of B- or N-doped graphene based materials will be introduced. Graphene based materials can be efficiently processed into various three-dimensional structures via self-assembly principles. Those carbon assembled structures with extremely large surface and high electro-conductivity are potentially useful for energy and environmental applications. Aqueous dispersion of graphene oxide shows liquid crystalline phase, whose spontaneous molecular ordering is useful for display or fiber spinning. Along with the structure control by directed nanoscale assembly, substitutional doping of graphene based materials with B- or N- can be attained via various chemical treatment methods. The resultant chemically modified carbon materials with tunable workfunction, charge carrier density and enhanced surface activity could be employed for various nanomaterials and nanodevices for improved functionalities and performances.

  2. Graphene-based screen-printed electrochemical (bio)sensors and their applications: Efforts and criticisms.

    PubMed

    Cinti, Stefano; Arduini, Fabiana

    2017-03-15

    K.S. Novoselov in his Nobel lecture (December 8, 2010), described graphene as "more than just a flat crystal" and summarized the best possible impression of graphene with (i) it is the first example of 2D atomic crystals, (ii) it demonstrated unique electronic properties, thanks to charge carriers which mimic massless relativistic particles, and (iii) it has promise for a number of applications. The fascinating and unusual properties of this 2D material were indeed recently investigated and exploited in several disciplines including physics, medicine, and chemistry, indicating the extremely versatile and polyedric aspect of this nanomaterial. The utilization of nanomaterials, printed technology, and microfluidics in electroanalysis has resulted in a period that can be called the "Electroanalysis Renaissance" (Escarpa, 2012) in which graphene is without any doubt a forefront nanomaterial. The rise in affordable fabrication processes, along with the great dispersing attitude in a plenty of matrices, have made graphene powerful in large-scale production of electrochemical platforms. Herein, we overview the employment of graphene to customize and/or fabricate printable based (bio)sensors over the past 5 years, including several modification approaches such as drop casting, screen- and inkjet-printing, different strategies of graphene-based sensing, and applications as well. The objective of this review is to provide a critical perspective related to advantages and disadvantages of using graphene in biosensing tools, based on screen-printed sensors.

  3. Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

    NASA Astrophysics Data System (ADS)

    Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

    2015-03-01

    We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm-1), light weight (1 mg cm-2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

  4. Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

    PubMed Central

    Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

    2015-01-01

    We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm−1), light weight (1 mg cm−2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics. PMID:25797022

  5. Graphene and its derivatives for cell biotechnology.

    PubMed

    Yang, Mei; Yao, Jun; Duan, Yixiang

    2013-01-07

    Every few years, a novel material with salient and often unique properties emerges and attracts both academic and industrial interest from the scientific community. The latest blockbuster is graphene, an increasingly important nanomaterial with atomically thin sheets of carbon, which has become a shining star and has shown great promise in the field of material science and nanotechnology. In recent years, it has changed from being the exclusive domain of physicists to the new passion of chemists and biologists. Graphene and its derivatives are now at the forefront of nearly every rapidly developing field of science and engineering, including biochemistry, biomedicine and certain cutting-edge interdisciplines that have intense popularity. The aim of this review is, firstly, to provide readers with a comprehensive, systematic and in-depth prospective of graphene's band structure and properties, and secondly, to concentrate on the recent progress in producing graphene-based nanomaterials, including mechanical exfoliation, chemical vapor deposition, plasma enhanced chemical vapor deposition, chemical reduction of graphene oxide, total organic synthesis, electrochemical synthesis and other fabrication strategies widely accepted by research scientists. At the same time, important definitions related to graphene are also introduced. The focus of this Tutorial Review is to emphasize the current situation and significance of using this new kind of two-dimensional material in the hot and emerging fields that are closely related to human life quality, for instance, cell biochemistry, bioimaging along with other frontier areas. Finally, the latest developments and possible impact that affect the heart of the whole scientific community have been discussed. In addition, the future trends along with potential challenges of this rapidly rising layered carbon have been pointed out in this paper.

  6. Safety considerations for graphene: lessons learnt from carbon nanotubes.

    PubMed

    Bussy, Cyrill; Ali-Boucetta, Hanene; Kostarelos, Kostas

    2013-03-19

    Many consider carbon nanomaterials the poster children of nanotechnology, attracting immense scientific interest from many disciplines and offering tremendous potential in a diverse range of applications due to their extraordinary properties. Graphene is the youngest in the family of carbon nanomaterials. Its isolation, description, and mass fabrication has followed that of fullerenes and carbon nanotubes. Graphene's development and its adoption by many industries will increase unintended or intentional human exposure, creating the need to determine its safety profile. In this Account, we compare the lessons learned from the development of carbon nanotubes with what is known about graphene, based on our own investigations and those of others. Despite both being carbon-based, nanotubes and graphene are two very distinct nanomaterials. We consider the key physicochemical characteristics (structure, surface, colloidal properties) for graphene and carbon nanotubes at three different physiological levels: cellular, tissue, and whole body. We summarize the evidence for health effects of both materials at all three levels. Overall, graphene and its derivatives are characterized by a lower aspect ratio, larger surface area, and better dispersibility in most solvents compared to carbon nanotubes. Dimensions, surface chemistry, and impurities are equally important for graphene and carbon nanotubes in determining both mechanistic (aggregation, cellular processes, biodistribution, and degradation kinetics) and toxicological outcomes. Colloidal dispersions of individual graphene sheets (or graphene oxide and other derivatives) can easily be engineered without metallic impurities, with high stability and less aggregation. Very importantly, graphene nanostructures are not fiber-shaped. These features theoretically offer significant advantages in terms of safety over inhomogeneous dispersions of fiber-shaped carbon nanotubes. However, studies that directly compare graphene with

  7. Engineering nanomaterial surfaces for biomedical applications.

    PubMed

    Wang, Xin; Liu, Li-Hong; Ramström, Olof; Yan, Mingdi

    2009-10-01

    Nanomaterials, possessing unique physical and chemical properties, have attracted much interest and generated wide varieties of applications. Recent investigations of functionalized nanomaterials have expanded into the biological area, providing a versatile platform in biomedical applications such as biomolecular sensing, biological imaging, drug delivery and disease therapy. Bio-functions and bio-compatibility of nanomaterials are realized by introducing synthetic ligands or natural biomolecules onto nanomaterials, and combining ligand-receptor biological interactions with intrinsic nanomaterial properties. Common strategies of engineering nanomaterial surfaces involve physisorption or chemisorption of desired ligands. We developed a photochemically initiated surface coupling chemistry, bringing versatility and simplicity to nanomaterial functionalization. The method was applied to attach underivatized carbohydrates efficiently on gold and iron oxide nanoparticles, and the resulting glyconanoparticles were successfully used as a sensitive biosensing system probing specific interactions between carbohydrates and proteins as well as bacteria.

  8. Engineering Nanomaterial Surfaces for Biomedical Applications

    PubMed Central

    Wang, Xin; Liu, Li-Hong; Ramström, Olof; Yan, Mingdi

    2014-01-01

    Nanomaterials, possessing unique physical and chemical properties, have attracted much interest and generated wide varieties of applications. Recent investigations of functionalized nanomaterials have expanded into the biological area, providing a versatile platform in biomedical applications such as biomolecular sensing, biological imaging, drug delivery and disease therapy. Bio-functions and bio-compatibility of nanomaterials are realized by introducing synthetic ligands or natural biomolecules onto nanomaterials, and combining ligand-receptor biological interactions with intrinsic nanomaterial properties. Common strategies of engineering nanomaterial surfaces involve physisorption or chemisorption of desired ligands. We developed a photochemically initiated surface coupling chemistry, bringing versatility and simplicity to nanomaterial functionalization. The method was applied to attach underivatized carbohydrates efficiently on gold and iron oxide nanoparticles, and the resulting glyconanoparticles were successfully used as a sensitive biosensing system probing specific interactions between carbohydrates and proteins as well as bacteria. PMID:19596820

  9. Cellulose nanomaterials in water treatment technologies.

    PubMed

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-05

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization.

  10. When biomolecules meet graphene: from molecular level interactions to material design and applications.

    PubMed

    Li, Dapeng; Zhang, Wensi; Yu, Xiaoqing; Wang, Zhenping; Su, Zhiqiang; Wei, Gang

    2016-12-01

    Graphene-based materials have attracted increasing attention due to their atomically-thick two-dimensional structures, high conductivity, excellent mechanical properties, and large specific surface areas. The combination of biomolecules with graphene-based materials offers a promising method to fabricate novel graphene-biomolecule hybrid nanomaterials with unique functions in biology, medicine, nanotechnology, and materials science. In this review, we focus on a summarization of the recent studies in functionalizing graphene-based materials using different biomolecules, such as DNA, peptides, proteins, enzymes, carbohydrates, and viruses. The different interactions between graphene and biomolecules at the molecular level are demonstrated and discussed in detail. In addition, the potential applications of the created graphene-biomolecule nanohybrids in drug delivery, cancer treatment, tissue engineering, biosensors, bioimaging, energy materials, and other nanotechnological applications are presented. This review will be helpful to know the modification of graphene with biomolecules, understand the interactions between graphene and biomolecules at the molecular level, and design functional graphene-based nanomaterials with unique properties for various applications.

  11. Enhanced neural cell adhesion and neurite outgrowth on graphene-based biomimetic substrates.

    PubMed

    Hong, Suck Won; Lee, Jong Ho; Kang, Seok Hee; Hwang, Eun Young; Hwang, Yu-Shik; Lee, Mi Hee; Han, Dong-Wook; Park, Jong-Chul

    2014-01-01

    Neural cell adhesion and neurite outgrowth were examined on graphene-based biomimetic substrates. The biocompatibility of carbon nanomaterials such as graphene and carbon nanotubes (CNTs), that is, single-walled and multiwalled CNTs, against pheochromocytoma-derived PC-12 neural cells was also evaluated by quantifying metabolic activity (with WST-8 assay), intracellular oxidative stress (with ROS assay), and membrane integrity (with LDH assay). Graphene films were grown by using chemical vapor deposition and were then coated onto glass coverslips by using the scooping method. Graphene sheets were patterned on SiO2/Si substrates by using photolithography and were then covered with serum for a neural cell culture. Both types of CNTs induced significant dose-dependent decreases in the viability of PC-12 cells, whereas graphene exerted adverse effects on the neural cells just at over 62.5 ppm. This result implies that graphene and CNTs, even though they were the same carbon-based nanomaterials, show differential influences on neural cells. Furthermore, graphene-coated or graphene-patterned substrates were shown to substantially enhance the adhesion and neurite outgrowth of PC-12 cells. These results suggest that graphene-based substrates as biomimetic cues have good biocompatibility as well as a unique surface property that can enhance the neural cells, which would open up enormous opportunities in neural regeneration and nanomedicine.

  12. Enhanced Neural Cell Adhesion and Neurite Outgrowth on Graphene-Based Biomimetic Substrates

    PubMed Central

    Lee, Jong Ho; Kang, Seok Hee; Hwang, Eun Young; Hwang, Yu-Shik; Lee, Mi Hee; Park, Jong-Chul

    2014-01-01

    Neural cell adhesion and neurite outgrowth were examined on graphene-based biomimetic substrates. The biocompatibility of carbon nanomaterials such as graphene and carbon nanotubes (CNTs), that is, single-walled and multiwalled CNTs, against pheochromocytoma-derived PC-12 neural cells was also evaluated by quantifying metabolic activity (with WST-8 assay), intracellular oxidative stress (with ROS assay), and membrane integrity (with LDH assay). Graphene films were grown by using chemical vapor deposition and were then coated onto glass coverslips by using the scooping method. Graphene sheets were patterned on SiO2/Si substrates by using photolithography and were then covered with serum for a neural cell culture. Both types of CNTs induced significant dose-dependent decreases in the viability of PC-12 cells, whereas graphene exerted adverse effects on the neural cells just at over 62.5 ppm. This result implies that graphene and CNTs, even though they were the same carbon-based nanomaterials, show differential influences on neural cells. Furthermore, graphene-coated or graphene-patterned substrates were shown to substantially enhance the adhesion and neurite outgrowth of PC-12 cells. These results suggest that graphene-based substrates as biomimetic cues have good biocompatibility as well as a unique surface property that can enhance the neural cells, which would open up enormous opportunities in neural regeneration and nanomedicine. PMID:24592382

  13. Contributions and mechanisms of action of graphite nanomaterials in ultra high performance concrete

    NASA Astrophysics Data System (ADS)

    Sbia, Libya Ahmed

    Ultra-high performance concrete (UHPC) reaches high strength and impermeability levels by using a relatively large volume fraction of a dense binder with fine microstructure in combination with high-quality aggregates of relatively small particle size, and reinforcing fibers. The dense microstructure of the cementitions binder is achieved by raising the packing density of the particulate matter, which covers sizes ranging from few hundred nanometers to few millimeters. The fine microstructure of binder in UHPC is realized by effective use of pozzolans to largely eliminate the coarse crystalline particles which exist among cement hydrates. UHPC incorporates (steel) fibers to overcome the brittleness of its dense, finely structured cementitious binder. The main thrust of this research is to evaluate the benefits of nanmaterials in UHPC. The dense, finely structure cementitious binder as well as the large volume fraction of the binder in UHPC benefit the dispersion of nanomaterials, and their interfacial interactions. The relatively close spacing of nanomaterials within the cementitious binder of UHPC enables them to render local reinforcement effects in critically stressed regions such as those in the vicinity of steel reinforcement and prestressing strands as well as fibers. Nanomaterials can also raise the density of the binder in UHPC by extending the particle size distribution down to the few nanometers range. Comprehensive experimental studies supported by theoretical investigations were undertake in order to optimize the use of nanomaterials in UHPC, identity the UHPC (mechanical) properties which benefit from the introduction of nanomaterials, and define the mechanisms of action of nanomaterials in UHPC. Carbon nanofiber was the primary nanomaterial used in this investigation. Some work was also conducted with graphite nanoplates. The key hypotheses of the project were as follows: (i) nanomaterials can make important contributions to the packing density of the

  14. The current graphene safety landscape - a literature mining exercise

    NASA Astrophysics Data System (ADS)

    Bussy, Cyrill; Jasim, Dhifaf; Lozano, Neus; Terry, Daniel; Kostarelos, Kostas

    2015-04-01

    As for any novel nanomaterial, the development of applications and industrial adoption of graphene-based materials will be subject to the confirmation of their safety profile and risk assessment. The analysis performed here maps the current knowledge of the safety of graphene-based materials as extracted by a literature mapping exercise of studies investigating these materials in preclinical animal models. We attempt to identify gaps for future studies and elucidate the critically important structure-function correlations between reported biological effects and graphene-based material physicochemical characteristics.As for any novel nanomaterial, the development of applications and industrial adoption of graphene-based materials will be subject to the confirmation of their safety profile and risk assessment. The analysis performed here maps the current knowledge of the safety of graphene-based materials as extracted by a literature mapping exercise of studies investigating these materials in preclinical animal models. We attempt to identify gaps for future studies and elucidate the critically important structure-function correlations between reported biological effects and graphene-based material physicochemical characteristics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00236b

  15. A biophysical understanding of the applications and implications of nanomaterials

    NASA Astrophysics Data System (ADS)

    Geitner, Nicholas K.

    The last few decades have seen an explosion in the study and application of nanomaterials that continues to grow at a dizzying pace. Despite exciting applications in nano-enabled electronics, materials, medicine, and environmental remediation, an understanding of the interactions of these materials with natural materials and systems and the resulting implications lags severely behind. The purpose of this dissertation is to illuminate these interactions as well as develop novel environmental applications from a biophysical perspective. Following an introduction and literature review in Chapter 1, Chapters 2-4 will explore the application of dendritic polymers as novel and biocompatible oil dispersants for more environmentally conscious response to catastrophic oil spills. Chapter 2 will serve as a proof-of-concept, exploring the interactions between two model dendritic polymers and two model oil hydrocarbons. Next, the biocompatibility of these nanoscale dispersing agents is addressed in Chapter 3, using a soil amoeba as the primary model organism with emphasis on the mechanisms of any observed toxicity. Finally, in an effort to minimize cationic charge-induced cytotoxicity, the cationic terminal functional groups of poly(amidoamine) (PAMAM) dendrimers are replaced with either anionic or neutral functional groups. The resulting changes in structure and oil-dispersing function of the original and modified dendrimers are then investigated. Chapter 5 details a study of the applications and implications of graphene derivatives. Specifically, the environmental persistence of graphene and graphene oxide are assessed by studying their interactions with natural amphiphiles using synergistic experiments and molecular dynamics simulations. The application of graphene oxide for the removal of polyaromatic hydrocarbons from aquatic systems is also investigated and compared to the efficacy of PAMAM dendrimers in the same application. Finally, Chapter 6 explores the interactions

  16. Hydrophobic End-Modulated Amino-Acid-Based Neutral Hydrogelators: Structure-Specific Inclusion of Carbon Nanomaterials.

    PubMed

    Choudhury, Pritam; Mandal, Deep; Brahmachari, Sayanti; Das, Prasanta Kumar

    2016-04-04

    Hydrophobic end-modulated l-phenylalanine-containing triethylene glycol monomethyl ether tagged neutral hydrogelators (1-4) are developed. Investigations determine the gelators' structure-dependent inclusion of carbon nanomaterials (CNMs) in the self-assembled fibrillar network (SAFIN). The gelators (1, 3, and 4) can immobilize water and aqueous buffer (pH 3-7) with a minimum gelator concentration of 10-15 mg mL(-1). The hydrophobic parts of the gelators are varied from a long chain (C-16) to an extended aromatic pyrenyl moiety, and their abilities to integrate 1 D and 2 D allotropes of carbon (i.e., single-walled carbon nanotubes (SWNTs) and graphene oxide (GO), respectively) within the gel are investigated. Gelator 1, containing a long alkyl chain (C-16), can include SWNTs, whereas the pyrene-containing 4 can include both SWNTs and GO. Gelator 3 fails to incorporate SWNTs or GO owing to its slow rate of gelation and possibly a mismatch between the aggregated structure and CNMs. The involvement of various forces in self-aggregated gelation and physicochemical changes occurring through CNM inclusion are examined by spectroscopic and microscopic techniques. The distinctive pattern of self-assembly of gelators 1 and 4 through J- and H-type aggregation might facilitate the structure-specific CNM inclusion. Inclusion of SWNTs/GO within the hydrogel matrix results in a reinforcement in mechanical stiffness of the composites compared with that of the native hydrogels.

  17. Humanin: a novel functional molecule for the green synthesis of graphene.

    PubMed

    Gurunathan, Sangiliyandi; Han, JaeWoong; Kim, Jin Hoi

    2013-11-01

    The synthesis of graphene nanosheets from graphene oxide is an interesting area of nanobiotechnology because graphene-based nanomaterials have potential applications in the biomedical field. In this study, we developed a green, rapid, and simple method for the synthesis of graphene from graphene oxide, which uses the mitochondrial polypeptide humanin as a reducing agent. Graphene was prepared via one-step reduction of graphene oxide under mild conditions in an aqueous solution, and the resulting substance was characterized using a range of analytical procedures. UV-vis absorption spectroscopy confirmed the reduction of graphene oxide to graphene. Fourier transform infrared spectroscopy was used to study the changes in the surface functionalities, and X-ray diffraction was used to investigate the crystal structure of graphene. High resolution scanning electron microscopy and atomic force microscopy were also employed to investigate the morphologies of the synthesized grapheme, and Raman spectroscopy was used to evaluate its single- and multi-layer properties. The results described here suggest that the potent reducing agent humanin may be used as a substitute for hydrazine during graphene synthesis, thereby providing a safe, biocompatible and green method for the efficient deoxygenation of graphene oxide that can be used for large-scale production and biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Developments and Applications of Electrogenerated Chemiluminescence Sensors Based on Micro- and Nanomaterials

    PubMed Central

    Hazelton, Sandra G.; Zheng, Xingwang; Zhao, Julia Xiaojun; Pierce, David T.

    2008-01-01

    A variety of recent developments and applications of electrogenerated chemiluminescence (ECL) for sensors are described. While tris(2,2′-bipyridyl)-ruthenium(II) and luminol have dominated and continue to pervade the field of ECL-based sensors, recent work has focused on use of these lumophores with micro- and nanomaterials. It has also extended to inherently luminescent nanomaterials, such as quantum dots. Sensor configurations including microelectrode arrays and microfluidics are reviewed and, with the recent trend toward increased use of nanomaterials, special attention has been given to sensors which include thin films, nanoparticles and nanotubes. Applications of ECL labels and examples of label-free sensing that incorporate nanomaterials are also discussed. PMID:27873850

  19. Carbon-based smart nanomaterials in biomedicine and neuroengineering

    PubMed Central

    Monaco, Antonina M

    2014-01-01

    Summary The search for advanced biomimetic materials that are capable of offering a scaffold for biological tissues during regeneration or of electrically connecting artificial devices with cellular structures to restore damaged brain functions is at the forefront of interdisciplinary research in materials science. Bioactive nanoparticles for drug delivery, substrates for nerve regeneration and active guidance, as well as supramolecular architectures mimicking the extracellular environment to reduce inflammatory responses in brain implants, are within reach thanks to the advancements in nanotechnology. In particular, carbon-based nanostructured materials, such as graphene, carbon nanotubes (CNTs) and nanodiamonds (NDs), have demonstrated to be highly promising materials for designing and fabricating nanoelectrodes and substrates for cell growth, by virtue of their peerless optical, electrical, thermal, and mechanical properties. In this review we discuss the state-of-the-art in the applications of nanomaterials in biological and biomedical fields, with a particular emphasis on neuroengineering. PMID:25383297

  20. Applications of carbon nanomaterials in bone tissue engineering.

    PubMed

    Venkatesan, Jayachandran; Pallela, Ramjee; Kim, Se-Kwon

    2014-10-01

    In the biomedical field, remarkable advancements have been made in artificial biomaterials for treating bone loss or defects. A variety of synthetic polymers, natural polymers and bioceramics are being used to develop artificial bones. Many natural and synthetic biomaterials, which are being investigated for their physiochemical role in vivo, are currently in the clinical trial stage. Carbon-based prostheses are promising materials that mimic the natural function of bone, e.g., mechanical strength. Recently, carbon-based bone materials, such as carbon nanotubes and graphene, have been widely investigated as potential solutions to several biomedical problems. This review summarizes the biophysicochemical and biomedical properties of carbon nanomaterials composed of polymer and ceramic structures and discusses their functionality in bone tissue engineering.

  1. A review of plasma-liquid interactions for nanomaterial synthesis

    NASA Astrophysics Data System (ADS)

    Chen, Qiang; Li, Junshuai; Li, Yongfeng

    2015-10-01

    Over the past few decades, a new branch of plasma research, nanomaterial (NM) synthesis through plasma-liquid interactions (PLIs), has been developing rapidly, mainly due to the various, recently developed plasma sources operating at low and atmospheric pressures. PLIs provide novel plasma-liquid interfaces where many physical and chemical processes take place. By exploiting these physical and chemical processes, various NMs ranging from noble metal nanoparticles to graphene nanosheets can easily be synthesized. The currently rapid development and increasingly wide utilization of the PLI method has naturally lead to an urgent need for the presentation of a general review. This paper reviews the current status of research on PLIs for NM synthesis. The focus is on a comprehensive understanding of the synthesis process and perceptive opinions on current issues and future challenges in this field.

  2. Graphene nanosheets as novel adsorbents in adsorption, preconcentration and removal of gases, organic compounds and metal ions.

    PubMed

    Yu, Jin-Gang; Yu, Lin-Yan; Yang, Hua; Liu, Qi; Chen, Xiao-Hong; Jiang, Xin-Yu; Chen, Xiao-Qing; Jiao, Fei-Peng

    2015-01-01

    Due to their high adsorption capacities, carbon-based nanomaterials such as carbon nanotubes, activated carbons, fullerene and graphene are widely used as the currently most promising functional materials. Since its discovery in 2004, graphene has exhibited great potential in many technological fields, such as energy storage materials, supercapacitors, resonators, quantum dots, solar cells, electronics, and sensors. The large theoretical specific surface area of graphene nanosheets (2630 m(2)·g(-1)) makes them excellent candidates for adsorption technologies. Further, graphene nanosheets could be used as substrates for decorating the surfaces of nanoparticles, and the corresponding nanocomposites could be applied as novel adsorbents for the removal of low concentrated contaminants from aqueous solutions. Therefore, graphene nanosheets will challenge the current existing adsorbents, including other types of carbon-based nanomaterials. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Crown ethers in graphene

    DOE PAGES

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; ...

    2014-11-13

    Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basicmore » structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.« less

  4. Crown ethers in graphene

    SciTech Connect

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; Gallego, Nidia C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Moyer, Bruce A.; Chisholm, Matthew F.

    2014-11-13

    Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.

  5. Graphene nanophotonic sensors

    NASA Astrophysics Data System (ADS)

    Zhu, Alexander Y.; Cubukcu, Ertugrul

    2015-09-01

    Graphene is known to possess a host of remarkable properties such as a zero bandgap at its Dirac point, broadband saturable optical absorption, ballistic carrier transport at room temperature, as well as extremely high stiffness and thermal conductivity. This has in turn made it a material of interest for many applications, ranging from fundamental physics studies to electronic devices. From a photonics perspective, graphene’s ability to support surface plasmon-polaritons with extremely small mode volumes in the infrared spectral regime and beyond renders it an ideal platform for strongly enhanced light-matter interactions at deeply subwavelength size scales. Together with its large bandwidth of operation, as well as intrinsic chemical stability and affinity to organic molecules, graphene serves as a natural candidate for numerous optics-based sensing applications. This article reviews recent works that highlight the various advantages of graphene in an optical sensing context. Specifically, it focuses on how the passive functionalization of graphene can improve the performance of existing optical sensors, and how its use as an active signal transduction element could lead to various novel or hybrid devices that extend the functionalities of traditional sensors.

  6. Probing Interfacial Processes on Graphene Surface by Mass Detection

    NASA Astrophysics Data System (ADS)

    Kakenov, Nurbek; Kocabas, Coskun

    2013-03-01

    In this work we studied the mass density of graphene, probed interfacial processes on graphene surface and examined the formation of graphene oxide by mass detection. The graphene layers were synthesized by chemical vapor deposition method on copper foils and transfer-printed on a quartz crystal microbalance (QCM). The mass density of single layer graphene was measured by investigating the mechanical resonance of the QCM. Moreover, we extended the developed technique to probe the binding dynamics of proteins on the surface of graphene, were able to obtain nonspecific binding constant of BSA protein of graphene surface in aqueous solution. The time trace of resonance signal showed that the BSA molecules rapidly saturated by filling the available binding sites on graphene surface. Furthermore, we monitored oxidation of graphene surface under oxygen plasma by tracing the changes of interfacial mass of the graphene controlled by the shifts in Raman spectra. Three regimes were observed the formation of graphene oxide which increases the interfacial mass, the release of carbon dioxide and the removal of small graphene/graphene oxide flakes. Scientific and Technological Research Council of Turkey (TUBITAK) grant no. 110T304, 109T209, Marie Curie International Reintegration Grant (IRG) grant no 256458, Turkish Academy of Science (TUBA-Gebip).

  7. Graphene as a signal amplifier for preparation of ultrasensitive electrochemical biosensors.

    PubMed

    Filip, Jaroslav; Kasák, Peter; Tkac, Jan

    2015-01-01

    Early diagnostics of diseases performed with minimal money and time consumption has become achievable due to recent advances in development of biosensors. These devices use biorecognition elements for selective interaction with an analyte and signal readout is obtained via different types of transducers. Operational characteristics of biosensors have been reported to improve substantially, when a diverse range of nanomaterials was employed. This review presents construction of electrochemical biosensors based on graphene, atomically thin 2D carbon crystals, which is currently intensively studied nanomaterial. The most attractive directions of graphene applications in biosensor preparation are discussed here including novel detection and amplification schemes exploiting graphene's unique electrochemical, physical and chemical properties. The future of graphene-based biosensors is most likely bright, but there is still a lot of work to do to fulfill high expectations.

  8. Emerging advances in cancer nanotheranostics with graphene nanocomposites: opportunities and challenges.

    PubMed

    Rahman, Mahfoozur; Akhter, Sohail; Ahmad, Mohammad Zaki; Ahmad, Javed; Addo, Richard T; Ahmad, Farhan Jalees; Pichon, Chantal

    2015-01-01

    As an inorganic nanomaterial, graphene nanocomposites have gained much attention in cancer nanotechnology compared with the other inorganic nanomaterial in recent times. Although a relatively new drug carrier, it has been extensively explored as a potential chemotherapeutic carrier and theranostic because of its numerous physicochemical properties, including, capability of multiple pay load, functionalization for drug targeting and photothermal effect. Despite potential benefit, its translation from bench to bed-side in cancer therapy is challenged due to its toxicity concern. Here, we discussed the present progress and future possibilities of graphene nanocomposites as a cancer theranostic. Moreover, the paper also exemplifies the effects of graphene/graphene oxide on tissues and organ functions in order to understand the extent and mechanism of toxicity.

  9. Fabrication and Cytocompatibility of In Situ Crosslinked Carbon Nanomaterial Films

    PubMed Central

    Patel, Sunny C.; Lalwani, Gaurav; Grover, Kartikey; Qin, Yi-Xian; Sitharaman, Balaji

    2015-01-01

    Assembly of carbon nanomaterials into two-dimensional (2D) coatings and films that harness their unique physiochemical properties may lead to high impact energy capture/storage, sensors, and biomedical applications. For potential biomedical applications, the suitability of current techniques such as chemical vapor deposition, spray and dip coating, and vacuum filtration, employed to fabricate macroscopic 2D all carbon coatings or films still requires thorough examination. Each of these methods presents challenges with regards to scalability, suitability for a large variety of substrates, mechanical stability of coatings or films, or biocompatibility. Herein we report a coating process that allow for rapid, in situ chemical crosslinking of multi-walled carbon nanotubes (MWCNTs) into macroscopic all carbon coatings. The resultant coatings were found to be continuous, electrically conductive, significantly more robust, and cytocompatible to human adipose derived stem cells. The results lay groundwork for 3D layer-on-layer nanomaterial assemblies (including various forms of graphene) and also opens avenues to further explore the potential of MWCNT films as a novel class of nano-fibrous mats for tissue engineering and regenerative medicine. PMID:26018775

  10. Fabrication and cytocompatibility of in situ crosslinked carbon nanomaterial films.

    PubMed

    Patel, Sunny C; Lalwani, Gaurav; Grover, Kartikey; Qin, Yi-Xian; Sitharaman, Balaji

    2015-05-28

    Assembly of carbon nanomaterials into two-dimensional (2D) coatings and films that harness their unique physiochemical properties may lead to high impact energy capture/storage, sensors, and biomedical applications. For potential biomedical applications, the suitability of current techniques such as chemical vapor deposition, spray and dip coating, and vacuum filtration, employed to fabricate macroscopic 2D all carbon coatings or films still requires thorough examination. Each of these methods presents challenges with regards to scalability, suitability for a large variety of substrates, mechanical stability of coatings or films, or biocompatibility. Herein we report a coating process that allow for rapid, in situ chemical crosslinking of multi-walled carbon nanotubes (MWCNTs) into macroscopic all carbon coatings. The resultant coatings were found to be continuous, electrically conductive, significantly more robust, and cytocompatible to human adipose derived stem cells. The results lay groundwork for 3D layer-on-layer nanomaterial assemblies (including various forms of graphene) and also opens avenues to further explore the potential of MWCNT films as a novel class of nano-fibrous mats for tissue engineering and regenerative medicine.

  11. Fabrication and Cytocompatibility of In Situ Crosslinked Carbon Nanomaterial Films

    NASA Astrophysics Data System (ADS)

    Patel, Sunny C.; Lalwani, Gaurav; Grover, Kartikey; Qin, Yi-Xian; Sitharaman, Balaji

    2015-05-01

    Assembly of carbon nanomaterials into two-dimensional (2D) coatings and films that harness their unique physiochemical properties may lead to high impact energy capture/storage, sensors, and biomedical applications. For potential biomedical applications, the suitability of current techniques such as chemical vapor deposition, spray and dip coating, and vacuum filtration, employed to fabricate macroscopic 2D all carbon coatings or films still requires thorough examination. Each of these methods presents challenges with regards to scalability, suitability for a large variety of substrates, mechanical stability of coatings or films, or biocompatibility. Herein we report a coating process that allow for rapid, in situ chemical crosslinking of multi-walled carbon nanotubes (MWCNTs) into macroscopic all carbon coatings. The resultant coatings were found to be continuous, electrically conductive, significantly more robust, and cytocompatible to human adipose derived stem cells. The results lay groundwork for 3D layer-on-layer nanomaterial assemblies (including various forms of graphene) and also opens avenues to further explore the potential of MWCNT films as a novel class of nano-fibrous mats for tissue engineering and regenerative medicine.

  12. Electron Temperature of the Arc Discharge for Nanomaterial Synthesis

    NASA Astrophysics Data System (ADS)

    Feurer, Matthew; Vekselman, Vladislav; Startton, Brentley; Raitses, Yevgeny; LaboratoryPlasma Nanosynthesis Team

    2016-10-01

    Since the discovery of different allotropes of carbon in the twentieth century many uses have been found for carbon based nanomaterials such as buckyballs, nanotubes (CNTs), and graphene. An atmospheric pressure arc discharge with graphite electrodes is a promising technique for producing large volumes of these carbon nanostructures. Plasma drives the synthesis providing carbon feedstock by anode ablation and sustaining required composition and temperature of nanomaterial species, as such it is important to characterize the plasma used in this process in order to control the quality and attributes of the resulting carbon nanostructures. In work we present detailed in-situ measurements of spatial distribution of arc plasma parameters obtained with optical emission spectroscopy (OES) diagnostics. The plasma temperature has been determined using Boltzmann diagram method with collisional radiative modeling due to plasma deviation from complete local thermodynamic equilibrium (LTE). Results of these measurements demonstrate a strong correlation between arc plasma and synthesis processes. This work was supported by US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  13. Biophysical influence of airborne carbon nanomaterials on natural pulmonary surfactant.

    PubMed

    Valle, Russell P; Wu, Tony; Zuo, Yi Y

    2015-05-26

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air-water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handle NP-PS interactions in the liquid phase. This technical limitation, inherent in current in vitro methodologies, makes it impossible to simulate how airborne NP deposit at the PS film and interact with it. Existing in vitro NP-PS studies using liquid-suspended particles have been shown to artificially inflate the no-observed adverse effect level of NP exposure when compared to in vivo inhalation studies and international occupational exposure limits (OELs). Here, we developed an in vitro methodology called the constrained drop surfactometer (CDS) to quantitatively study PS inhibition by airborne CNM. We show that airborne multiwalled carbon nanotubes and graphene nanoplatelets induce a concentration-dependent PS inhibition under physiologically relevant conditions. The CNM aerosol concentrations controlled in the CDS are comparable to those defined in international OELs. Development of the CDS has the potential to advance our understanding of how submicron airborne nanomaterials affect the PS lining of the lung.

  14. Exploring Carbon Nanomaterial Diversity for Nucleation of Protein Crystals

    NASA Astrophysics Data System (ADS)

    Govada, Lata; Leese, Hannah S.; Saridakis, Emmanuel; Kassen, Sean; Chain, Benny; Khurshid, Sahir; Menzel, Robert; Hu, Sheng; Shaffer, Milo S. P.; Chayen, Naomi E.

    2016-02-01

    Controlling crystal nucleation is a crucial step in obtaining high quality protein crystals for structure determination by X-ray crystallography. Carbon nanomaterials (CNMs) including carbon nanotubes, graphene oxide, and carbon black provide a range of surface topographies, porosities and length scales; functionalisation with two different approaches, gas phase radical grafting and liquid phase reductive grafting, provide routes to a range of oligomer functionalised products. These grafted materials, combined with a range of controls, were used in a large-scale assessment of the effectiveness for protein crystal nucleation of 20 different carbon nanomaterials on five proteins. This study has allowed a direct comparison of the key characteristics of carbon-based nucleants: appropriate surface chemistry, porosity and/or roughness are required. The most effective solid system tested in this study, carbon black nanoparticles functionalised with poly(ethylene glycol) methyl ether of mean molecular weight 5000, provides a novel highly effective nucleant, that was able to induce crystal nucleation of four out of the five proteins tested at metastable conditions.

  15. Carbon nanomaterials combined with metal nanoparticles for theranostic applications

    PubMed Central

    Modugno, Gloria; Ménard-Moyon, Cécilia; Prato, Maurizio; Bianco, Alberto

    2015-01-01

    Among targeted delivery systems, platforms with nanosize dimensions, such as carbon nanomaterials (CNMs) and metal nanoparticles (NPs), have shown great potential in biomedical applications. They have received considerable interest in recent years, especially with respect to their potential utilization in the field of cancer diagnosis and therapy. The many functions of nanomaterials provide opportunities to use them as multimodal agents for theranostics, a combination of therapy and diagnosis. Carbon nanotubes and graphene are some of the most widely used CNMs because of their unique structural and physicochemical properties. Their high specific surface area allows for efficient drug loading and the possibility of functionalization with various bioactive molecules. In addition, CNMs are ideal platforms for the attachment of NPs. In the biomedical field, NPs have also shown tremendous potential for use in drug delivery, non-invasive tumour imaging and early detection due to their optical and magnetic properties. NP/CNM hybrids not only combine the unique properties of the NPs and CNMs but they also exhibit new properties arising from interactions between the two entities. In this review, the preparation of CNMs conjugated to different types of metal NPs and their applications in diagnosis, imaging, therapy and theranostics are presented. PMID:25323135

  16. Near-infrared light-responsive nanomaterials in cancer therapeutics.

    PubMed

    Shanmugam, Vijayakumar; Selvakumar, S; Yeh, Chen-Sheng

    2014-09-07

    Noninvasive techniques, such as breath tests (urea breath test), blood pressure measurements using a sphygmomanometer and electrocardiography, were employed by a physician to perform classical diagnosis. The use of state-of-the-art noninvasive therapies at the organ level in modern medicine has gradually become possible. However, cancer treatment demands spatially and temporally controlled noninvasive therapy at the cell level because nonspecific toxicity often causes complicated side effects. To increase survival in cancer patients further, combination therapy and combination drugs are explored which demand high specificity to avoid combined-drug side effects. We believe that high specificity could be obtained by implementing near-infrared (NIR) light-assisted nanoparticles in photothermal therapy, chemotherapy, and photodynamic therapy. To refine this therapy and subsequently achieve high efficiency, novel nanomaterials have been designed and modified either to enhance the uptake and drug delivery to the cancer site, or control treatment to administer therapy efficiently. These modifications and developments have been demonstrated to achieve spatial and temporal control when conducting an in vivo xenograft, because the NIR light penetrated effectively the biological tissue. The nanoplatforms discussed in this review are grouped under the following subheadings: Au nanorods (NRs), Au nanoshells, other Au-related nanomaterials, graphene oxide, upconversion nanoparticles, and other related materials (including materials such as CuS, Fe3O4-related systems, and carbon nanotubes (CNTs)).

  17. Exploring Carbon Nanomaterial Diversity for Nucleation of Protein Crystals

    PubMed Central

    Govada, Lata; Leese, Hannah S.; Saridakis, Emmanuel; Kassen, Sean; Chain, Benny; Khurshid, Sahir; Menzel, Robert; Hu, Sheng; Shaffer, Milo S. P.; Chayen, Naomi E.

    2016-01-01

    Controlling crystal nucleation is a crucial step in obtaining high quality protein crystals for structure determination by X-ray crystallography. Carbon nanomaterials (CNMs) including carbon nanotubes, graphene oxide, and carbon black provide a range of surface topographies, porosities and length scales; functionalisation with two different approaches, gas phase radical grafting and liquid phase reductive grafting, provide routes to a range of oligomer functionalised products. These grafted materials, combined with a range of controls, were used in a large-scale assessment of the effectiveness for protein crystal nucleation of 20 different carbon nanomaterials on five proteins. This study has allowed a direct comparison of the key characteristics of carbon-based nucleants: appropriate surface chemistry, porosity and/or roughness are required. The most effective solid system tested in this study, carbon black nanoparticles functionalised with poly(ethylene glycol) methyl ether of mean molecular weight 5000, provides a novel highly effective nucleant, that was able to induce crystal nucleation of four out of the five proteins tested at metastable conditions. PMID:26843366

  18. Pathophysiologic mechanisms of biomedical nanomaterials.

    PubMed

    Wang, Liming; Chen, Chunying

    2016-05-15

    Nanomaterials (NMs) have been widespread used in biomedical fields, daily consuming, and even food industry. It is crucial to understand the safety and biomedical efficacy of NMs. In this review, we summarized the recent progress about the physiological and pathological effects of NMs from several levels: protein-nano interface, NM-subcellular structures, and cell-cell interaction. We focused on the detailed information of nano-bio interaction, especially about protein adsorption, intracellular trafficking, biological barriers, and signaling pathways as well as the associated mechanism mediated by nanomaterials. We also introduced related analytical methods that are meaningful and helpful for biomedical effect studies in the future. We believe that knowledge about pathophysiologic effects of NMs is not only significant for rational design of medical NMs but also helps predict their safety and further improve their applications in the future.

  19. Poly-cytosine DNA as a High-Affinity Ligand for Inorganic Nanomaterials.

    PubMed

    Lu, Chang; Huang, Zhicheng; Liu, Biwu; Liu, Yibo; Ying, Yibin; Liu, Juewen

    2017-05-22

    Attaching DNA to nanomaterials is the basis for DNA-directed assembly, sensing, and drug delivery using such hybrid materials. Poly-cytosine (poly-C) DNA is a high affinity ligand for four types of commonly used nanomaterials, including nanocarbons (graphene oxide and single-walled carbon nanotubes), transition metal dichalcogenides (MoS2 and WS2 ), metal oxides (Fe3 O4 and ZnO), and metal nanoparticles (Au and Ag). Compared to other homo-DNA sequences, poly-C DNA has the highest affinity for the first three types of materials. Using a diblock DNA containing a poly-C block to attach to surfaces, the target DNA was successfully hybridized to the other block on graphene oxide more efficiently than that containing a typical poly-A block, especially in the presence of non-specific background DNA, proteins, or surfactants. This work provides a simple solution for functionalizing nanomaterials with non-modified DNA and offers new insights into DNA biointerfaces. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Final Report: "Energetics of Nanomaterials

    SciTech Connect

    Navrotsky, Alexandra; Ross, Nancy; Woodfield, Brian

    2015-02-14

    Nanomaterials, solids with very small particle size, form the basis of new technologies that are revolutionizing fields such as energy, lighting, electronics, medical diagnostics, and drug delivery. These nanoparticles are different from conventional bulk materials in many ways we do not yet fully understand. This project focused on their structure and thermodynamics and emphasized the role of water in nanoparticle surfaces. Using a unique and synergistic combination of high-tech techniques—namely oxide melt solution calorimetry, cryogenic heat capacity measurements, and inelastic neutron scattering—this work has identified differences in structure, thermodynamic stability, and water behavior on nanoparticles as a function of composition and particle size. The systematics obtained increase the fundamental understanding needed to synthesize, retain, and apply these technologically important nanomaterials and to predict and tailor new materials for enhanced functionality, eventually leading to a more sustainable way of life. Highlights are reported on the following topics: surface energies, thermochemistry of nanoparticles, and changes in stability at the nanoscale; heat capacity models and the gapped phonon spectrum; control of pore structure, acid sites, and thermal stability in synthetic γ-aluminas; the lattice contribution is the same for bulk and nanomaterials; and inelastic neutron scattering studies of water on nanoparticle surfaces.

  1. Nanomaterial-Enabled Neural Stimulation

    PubMed Central

    Wang, Yongchen; Guo, Liang

    2016-01-01

    Neural stimulation is a critical technique in treating neurological diseases and investigating brain functions. Traditional electrical stimulation uses electrodes to directly create intervening electric fields in the immediate vicinity of neural tissues. Second-generation stimulation techniques directly use light, magnetic fields or ultrasound in a non-contact manner. An emerging generation of non- or minimally invasive neural stimulation techniques is enabled by nanotechnology to achieve a high spatial resolution and cell-type specificity. In these techniques, a nanomaterial converts a remotely transmitted primary stimulus such as a light, magnetic or ultrasonic signal to a localized secondary stimulus such as an electric field or heat to stimulate neurons. The ease of surface modification and bio-conjugation of nanomaterials facilitates cell-type-specific targeting, designated placement and highly localized membrane activation. This review focuses on nanomaterial-enabled neural stimulation techniques primarily involving opto-electric, opto-thermal, magneto-electric, magneto-thermal and acousto-electric transduction mechanisms. Stimulation techniques based on other possible transduction schemes and general consideration for these emerging neurotechnologies are also discussed. PMID:27013938

  2. Novel Nanomaterials for Clinical Neuroscience

    PubMed Central

    Gilmore, Jamie L.; Yi, Xiang; Quan, Lingdong; Kabanov, Alexander V.

    2008-01-01

    Neurodegenerative disorders including Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and stroke are rapidly increasing as population ages. The field of nanomedicine is rapidly expanding and promises revolutionary advances to the diagnosis and treatment of devastating human diseases. This paper provides an overview of novel nanomaterials that have potential to improve diagnosis and therapy of neurodegenerative disorders. Examples include liposomes, nanoparticles, polymeric micelles, block ionomer complexes, nanogels, and dendrimers that have been tested clinically or in experimental models for delivery of drugs, genes, and imaging agents. More recently discovered nanotubes and nanofibers are evaluated as promising scaffolds for neuroregeneration. Novel experimental neuroprotective strategies also include nanomaterials, such as fullerenes, which have antioxidant properties to eliminate reactive oxygen species in the brain to mitigate oxidative stress. Novel technologies to enable these materials to cross the blood brain barrier will allow efficient systemic delivery of therapeutic and diagnostic agents to the brain. Furthermore, by combining such nanomaterials with cell-based delivery strategies, the outcomes of neurodegenerative disorders can be greatly improved. PMID:18210200

  3. Core level binding energies of functionalized and defective graphene

    PubMed Central

    Kaukonen, Markus; Havu, Paula; Ljungberg, Mathias P; Ayala, Paola; Kauppinen, Esko I

    2014-01-01

    Summary X-ray photoelectron spectroscopy (XPS) is a widely used tool for studying the chemical composition of materials and it is a standard technique in surface science and technology. XPS is particularly useful for characterizing nanostructures such as carbon nanomaterials due to their reduced dimensionality. In order to assign the measured binding energies to specific bonding environments, reference energy values need to be known. Experimental measurements of the core level signals of the elements present in novel materials such as graphene have often been compared to values measured for molecules, or calculated for finite clusters. Here we have calculated core level binding energies for variously functionalized or defected graphene by delta Kohn–Sham total energy differences in the real-space grid-based projector-augmented wave density functional theory code (GPAW). To accurately model extended systems, we applied periodic boundary conditions in large unit cells to avoid computational artifacts. In select cases, we compared the results to all-electron calculations using an ab initio molecular simulations (FHI-aims) code. We calculated the carbon and oxygen 1s core level binding energies for oxygen and hydrogen functionalities such as graphane-like hydrogenation, and epoxide, hydroxide and carboxylic functional groups. In all cases, we considered binding energy contributions arising from carbon atoms up to the third nearest neighbor from the functional group, and plotted C 1s line shapes by using experimentally realistic broadenings. Furthermore, we simulated the simplest atomic defects, namely single and double vacancies and the Stone–Thrower–Wales defect. Finally, we studied modifications of a reactive single vacancy with O and H functionalities, and compared the calculated values to data found in the literature. PMID:24605278

  4. Graphene Kirigami

    NASA Astrophysics Data System (ADS)

    Blees, Melina; Rose, Peter; Barnard, Arthur; Roberts, Samantha; McEuen, Paul L.

    2014-03-01

    We have developed a powerful new approach to working with graphene by applying the principles of kirigami, the sculptural art of paper cutting. We have release graphene from the surface, allowing us to treat it like a sheet of atom-thick paper. Working in water, we can pull the graphene along the surface or peel it up entirely. Combining this technique with lithographic patterning, we have created a variety of graphene kirigami devices including three-dimensional structures and resilient, atomically-thin hinges. We have also created soft in-plane springs by patterning a series of cuts into the graphene. The spring constants of these devices depend on the pattern of cuts, so the patterned graphene becomes an adjustable mechanical metamaterial. With possible spring constants ranging from 1 N/m to 10-9 N/m, these springs could be used as sensitive force measurement devices. Such kirigami patterning techniques could also be applied to flexible and stretchable electronics, including soft electrodes for biological experiments. This unusual way of interacting with graphene opens up a world of potential applications that we are just beginning to explore.

  5. Functionalized carbon nanotubes and graphene-based materials for energy storage.

    PubMed

    Wang, Bin; Hu, Chuangang; Dai, Liming

    2016-12-13

    Carbon nanotubes (CNTs) or graphene-based nanomaterials functionalized by different strategies have attracted great attention for energy storage due to their large specific surface area, high conductivity, and good mechanical properties. This feature article presents an overview of the recent progress in the functionalization of CNTs and graphene-based materials for energy storage applications in supercapacitors and batteries, along with challenges and perspectives in this exciting field.

  6. Fabrication and characterization of polycaprolactone-graphene powder electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Ginestra, Paola; Ghazinejad, Maziar; Madou, Marc; Ceretti, Elisabetta

    2016-09-01

    Porous fibrous membranes having multiple scales geometries and tailored properties have become attractive microfabrication materials in recent years. Due to the feasibility of incorporating graphene in electrospun nanofibres and the growing interest on these nanomaterials, the present paper focuses on the electrospinning of Poly (ɛ-Caprolactone) (PCL) solutions in the presence of different amounts of Graphene platelets. Electrospinning is a process whereby ultrafine fibers are formed in a high-voltage electrostatic field. The morphological appearance, fiber diameter, and structure of PCL nanofibers produced by the electrospinning process were studied in the presence of different concentration of graphene. Moreover, the effect of a successful incorporation of graphene nanosheets into PCL polymer nanofibers was analyzed. Scanning electron microscope micrographs of the electrospun fibers showed that the average fiber diameter increases in the presence of graphene. Furthermore, the intrinsic properties developed due to the interactions of graphene and PCL improved the mechanical properties of the nanofibers. The results reveal the effect of various graphene concentrations on PCL and the strong interfacial interactions between the graphene platelets phase and the polymer matrix. The functional complexity of the electrospun fibers provides significant advantages over other techniques and shows the promise of these fibers for many applications including air/water filters, sensors, organic solar cells, smart textiles, biocompatible scaffolds for tissue engineering and load-bearing applications. Optimizing deposition efficiency, however, is a necessary milestone for the widespread use of this technique.

  7. Rheology and morphology of pristine graphene/polyacrylamide gels.

    PubMed

    Das, Sriya; Irin, Fahmida; Ma, Lan; Bhattacharia, Sanjoy K; Hedden, Ronald C; Green, Micah J

    2013-09-11

    Enhancement of toughness in nanomaterial-based hydrogels is a critical metric for many of their engineering applications. Pristine graphene-polyacrylamide (PAM) hydrogels are synthesized via in situ polymerization of acrylamide monomer in PAM-stabilized graphene dispersion. In-situ polymerization leads to the uniform dispersion of the graphene sheets in the hydrogel. The graphene sheets interact with the elastic chains of the hydrogel through physisorption and permit gelation in the absence of any chemical cross-linker. This study represents the first report of pristine graphene as a physical cross-linker in a hydrogel. The properties of the graphene-polymer hydrogel are characterized by rheological measurements and compressive tests, revealing an increase in the storage modulus and toughness of the hydrogels compared to the chemically cross-linked PAM analogues. The physically cross-linked graphene hydrogels also exhibit self-healing properties. These hydrogels prove to be efficient precursors for graphene-PAM aerogels with enhanced electrical conductivity and thermal stability.

  8. Molecular interactions and thermal transport in ionic liquids with carbon nanomaterials.

    PubMed

    França, João M P; Nieto de Castro, Carlos A; Pádua, Agílio A H

    2017-07-05

    We used molecular dynamics simulation to study the effect of suspended carbon nanomaterials, nanotubes and graphene sheets, on the thermal conductivity of ionic liquids, an issue related to understanding the properties of nanofluids. One important aspect that we developed is an atomistic model of the interactions between the organic ions and carbon nanomaterials, so we did not rely on existing force fields for small organic molecules or assume simple combining rules to describe the interactions at the liquid/material interface. Instead, we used quantum calculations with a density functional suitable for non-covalent interactions to parameterize an interaction model, including van der Waals terms and also atomic partial charges on the materials. We fitted a n-m interaction potential function with n values of 9 or 10 and m values between 5 and 8, so a 12-6 Lennard-Jones function would not fit the quantum calculations. For the atoms of ionic liquids and carbon nanomaterials interacting among themselves, we adopted existing models from the literature. We studied the imidazolium ionic liquids [C4C1im][SCN], [C4C1im][N(CN)2], [C4C1im][C(CN)3] and [C4C1im][(CF3SO2)2N]. Attraction is stronger for cations (than for anions) above and below the π-system of the nanomaterials, whereas anions show stronger attraction for the hydrogenated edges. The ordering of ions around and inside (7,7) and (10,10) single-walled nanotubes, and near a stack of graphene sheets, was analysed in terms of density distribution functions. We verified that anions are found, as well as cations, in the first interfacial layer interacting with the materials, which is surprising given the interaction potential surfaces. The thermal conductivity of the ionic liquids and of composite systems containing one nanotube or one graphene stack in suspension was calculated using non-equilibrium molecular dynamics. Thermal conductivity was calculated along the axis of the nanotube and across the planes of graphene

  9. Interactions of amino acids with adatoms(Ti, C, O) decorated graphene via effect of charging

    NASA Astrophysics Data System (ADS)

    Salmankurt, Bahadır; Gürel, Hikmet Hakan

    2017-02-01

    As amino acids take an important role in biology, it is envisaged that understanding of their interactions with nanomate-rials can resolve critical problems in the field of biomedicine. Graphene, single atom thick hexagonal lattice of sp2-bonded carbon, can be used for this purpose. The remarkable properties of graphene sheets could facilitate their application in areas like hydrogen technology, electronics, and sensing. In this work, we report density functional theory calculations of the adsorption of Histidine and Leucine molecules on pristine and decorated (Ti,C and O) graphene. The obtained binding energies of molecules on graphene surface are in good agreement previous studies. The chemisorption is achieved when Graphene is decorated with Ti and C. It is also shown that how modify structural properties of the molecules on pristine Graphene by applied charging for the first time.

  10. Potential toxicity of graphene to cell functions via disrupting protein-protein interactions.

    PubMed

    Luan, Binquan; Huynh, Tien; Zhao, Lin; Zhou, Ruhong

    2015-01-27

    While carbon-based nanomaterials such as graphene and carbon nanotubes (CNTs) have become popular in state-of-the-art nanotechnology, their biological safety and underlying molecular mechanism is still largely unknown. Experimental studies have been focused at the cellular level and revealed good correlations between cell's death and the application of CNTs or graphene. Using large-scale all-atom molecular dynamics simulations, we theoretically investigate the potential toxicity of graphene to a biological cell at molecular level. Simulation results show that the hydrophobic protein-protein interaction (or recognition) that is essential to biological functions can be interrupted by a graphene nanosheet. Due to the hydrophobic nature of graphene, it is energetically favorable for a graphene nanosheet to enter the hydrophobic interface of two contacting proteins, such as a dimer. The forced separation of two functional proteins can disrupt the cell's metabolism and even lead to the cell's mortality.

  11. Behavior and toxicity of graphene and its functionalized derivatives in biological systems.

    PubMed

    Yang, Kai; Li, Yingjie; Tan, Xiaofang; Peng, Rui; Liu, Zhuang

    2013-05-27

    Graphene, as a class of 2D carbon nanomaterial, has attracted tremendous interest in different areas in recent years including biomedicine. The toxicity and behavior of graphene in biological systems are thus important fundamental issues that require significant attention. In this article, the toxicity of graphene is reviewed by describing the behavior of graphene and its derivatives in microorganisms, cells, and animals. Despite certain inconsistencies in several detailed experimental results and hypotheses of toxicity mechanisms, results from numerous reports all agree that the physicochemical properties such as surface functional groups, charges, coatings, sizes, and structural defects of graphene may affect its in vitro/in vivo behavior as well as its toxicity in biological systems. It is hoped that this review article will provide an overview understanding of the impacts, behavior, and toxicology of graphene and its derivatives in various biological systems.

  12. Toxicity of nanomaterials; an undermined issue.

    PubMed

    Mogharabi, Mehdi; Abdollahi, Mohammad; Faramarzi, Mohammad Ali

    2014-08-15

    Nanomaterials are employed in extensive variety of commercial products such as electronic components, cosmetics, food, sports equipment, biomedical applications, and medicine. With the increasing utilization of engineered nanomaterials, the potential exposure of human to nanoparticles is rapidly increasing. Nowadays when new nanomaterials with new applications are introduced, mostly good and positive effects are mentioned whereas possible hazards arising from nanosize of the compounds are undermined. Toxicology studies of nanomaterials demonstrate some adverse effects in some human organs such as central nerve system, immune system, and lung. There is lack of complete information about human toxicity and environmental waste of nanomaterials. We aimed to highlight current toxicological concerns of potentially useful nanomaterials which are now used in pharmaceutical and biomedical sciences.

  13. Graphene-Based Environmental Barriers

    PubMed Central

    Guo, Fei; Silverberg, Gregory; Bowers, Shin; Kim, Sang-Pil; Datta, Dibakar; Shenoy, Vivek; Hurt, Robert H.

    2012-01-01

    Many environmental technologies rely on containment by engineered barriers that inhibit the release or transport of toxicants. Graphene is a new, atomically thin, two-dimensional sheet material, whose aspect ratio, chemical resistance, flexibility, and impermeability make it a promising candidate for inclusion in a next generation of engineered barriers. Here we show that ultrathin graphene oxide (GO) films can serve as effective barriers for both liquid and vapor permeants. First, GO deposition on porous substrates is shown to block convective flow at much lower mass loadings than other carbon nanomaterials, and can achieve hydraulic conductivities of 5×10−12 cm/s or lower. Second we show that ultrathin GO films of only 20 nm thickness coated on polyethylene films reduce their vapor permeability by 90% using elemental mercury as a model vapor toxicant. The barrier performance of GO in this thin-film configuration is much better than the Nielsen model limit, which describes ideal behavior of flake-like fillers uniformly imbedded in a polymer. The Hg barrier performance of GO films is found to be sensitive to residual water in the films, which is consistent with molecular dynamics (MD) simulations that show lateral diffusion of Hg atoms in graphene interlayer spaces that have been expanded by hydration. PMID:22717015

  14. Carbon and graphene double protection strategy to improve the SnO(x) electrode performance anodes for lithium-ion batteries.

    PubMed

    Zhu, Jian; Lei, Danni; Zhang, Guanhua; Li, Qiuhong; Lu, Bingan; Wang, Taihong

    2013-06-21

    SnOx is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. In this paper, SnOx carbon nanofibers (SnOx@CNFs) are firstly obtained in the form of a nonwoven mat by electrospinning followed by calcination in a 0.02 Mpa environment at 500 °C. Then we use a simple mixing method for the synthesis of SnOx@CNF@graphene (SnOx@C@G) nanocomposite. By this technique, the SnOx@CNFs can be homogeneously deposited in graphene nanosheets (GNSs). The highly scattered SnOx@C@G composite exhibits enhanced electrochemical performance as anode material for LIBs. The double protection strategy to improve the electrode performance through producing SnOx@C@G composites is versatile. In addition, the double protection strategy can be extended to the fabrication of various types of composites between metal oxides and graphene nanomaterials, possessing promising applications in catalysis, sensing, supercapacitors and fuel cells.

  15. Facile hybridization of Ni@Fe2O3 superparticles with functionalized reduced graphene oxide and its application as anode material in lithium-ion batteries.

    PubMed

    Backert, Gregor; Oschmann, Bernd; Tahir, Muhammad Nawaz; Mueller, Franziska; Lieberwirth, Ingo; Balke, Benjamin; Tremel, Wolfgang; Passerini, Stefano; Zentel, Rudolf

    2016-09-15

    In our present work we developed a novel graphene wrapping approach of Ni@Fe2O3 superparticles, which can be extended as a concept approach for other nanomaterials as well. It uses sulfonated reduced graphene oxide, but avoids thermal treatments and use of toxic agents like hydrazine for its reduction. The modification of graphene oxide is achieved by the introduction of sulfate groups accompanied with reduction and elimination reactions, due to the treatment with oleum. The successful wrapping of nanoparticles is proven by energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy and Raman spectroscopy. The developed composite material shows strongly improved performance as anode material in lithium-ion batteries (compared to unwrapped Ni@Fe2O3) as it offers a reversible capacity of 1051mAhg(-1) after 40 cycles at C/20, compared with 460mAhg(-1) for unwrapped Ni@Fe2O3. The C rate capability is also improved by the wrapping approach, as specific capacities for wrapped particles are about twice of those offered by unwrapped particles. Additionally, the benefit for the use of the advanced superparticle morphology is demonstrated by comparing wrapped Ni@Fe2O3 particles with wrapped Fe2O3 nanorice.

  16. Using graphene networks to build bioinspired self-monitoring ceramics

    NASA Astrophysics Data System (ADS)

    Picot, Olivier T.; Rocha, Victoria G.; Ferraro, Claudio; Ni, Na; D'Elia, Eleonora; Meille, Sylvain; Chevalier, Jerome; Saunders, Theo; Peijs, Ton; Reece, Mike J.; Saiz, Eduardo

    2017-02-01

    The properties of graphene open new opportunities for the fabrication of composites exhibiting unique structural and functional capabilities. However, to achieve this goal we should build materials with carefully designed architectures. Here, we describe the fabrication of ceramic-graphene composites by combining graphene foams with pre-ceramic polymers and spark plasma sintering. The result is a material containing an interconnected, microscopic network of very thin (20-30 nm), electrically conductive, carbon interfaces. This network generates electrical conductivities up to two orders of magnitude higher than those of other ceramics with similar graphene or carbon nanotube contents and can be used to monitor `in situ' structural integrity. In addition, it directs crack propagation, promoting stable crack growth and increasing the fracture resistance by an order of magnitude. These results demonstrate that the rational integration of nanomaterials could be a fruitful path towards building composites combining unique mechanical and functional performances.

  17. Enhancing light absorption in graphene with plasmonic lattices

    NASA Astrophysics Data System (ADS)

    Pirruccio, G.; Ramezani, M.; Gómez Rivas, J.

    2017-07-01

    We present a novel strategy based on metallic arrays of nanoparticles for enhancing the optical absorption in a monolayer of graphene. The collective resonances sustained by the metallic array and arising from the radiative coupling of localized surface plasmon resonances favour the interaction between the graphene layer and the light distributed in the structure. We measure the dispersion diagram of the allowed hybrid plasmonic-photonic modes and we calculate that one of these modes leads to an enhancement of the optical absorption of graphene by a factor 7. We propose to exploit this result for the rational design of graphene-based photodetectors. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  18. Using graphene networks to build bioinspired self-monitoring ceramics

    PubMed Central

    Picot, Olivier T.; Rocha, Victoria G.; Ferraro, Claudio; Ni, Na; D'Elia, Eleonora; Meille, Sylvain; Chevalier, Jerome; Saunders, Theo; Peijs, Ton; Reece, Mike J.; Saiz, Eduardo

    2017-01-01

    The properties of graphene open new opportunities for the fabrication of composites exhibiting unique structural and functional capabilities. However, to achieve this goal we should build materials with carefully designed architectures. Here, we describe the fabrication of ceramic-graphene composites by combining graphene foams with pre-ceramic polymers and spark plasma sintering. The result is a material containing an interconnected, microscopic network of very thin (20–30 nm), electrically conductive, carbon interfaces. This network generates electrical conductivities up to two orders of magnitude higher than those of other ceramics with similar graphene or carbon nanotube contents and can be used to monitor ‘in situ' structural integrity. In addition, it directs crack propagation, promoting stable crack growth and increasing the fracture resistance by an order of magnitude. These results demonstrate that the rational integration of nanomaterials could be a fruitful path towards building composites combining unique mechanical and functional performances. PMID:28181518

  19. Using graphene networks to build bioinspired self-monitoring ceramics.

    PubMed

    Picot, Olivier T; Rocha, Victoria G; Ferraro, Claudio; Ni, Na; D'Elia, Eleonora; Meille, Sylvain; Chevalier, Jerome; Saunders, Theo; Peijs, Ton; Reece, Mike J; Saiz, Eduardo

    2017-02-09

    The properties of graphene open new opportunities for the fabrication of composites exhibiting unique structural and functional capabilities. However, to achieve this goal we should build materials with carefully designed architectures. Here, we describe the fabrication of ceramic-graphene composites by combining graphene foams with pre-ceramic polymers and spark plasma sintering. The result is a material containing an interconnected, microscopic network of very thin (20-30 nm), electrically conductive, carbon interfaces. This network generates electrical conductivities up to two orders of magnitude higher than those of other ceramics with similar graphene or carbon nanotube contents and can be used to monitor 'in situ' structural integrity. In addition, it directs crack propagation, promoting stable crack growth and increasing the fracture resistance by an order of magnitude. These results demonstrate that the rational integration of nanomaterials could be a fruitful path towards building composites combining unique mechanical and functional performances.

  20. Annealing free, clean graphene transfer using alternative polymer scaffolds

    NASA Astrophysics Data System (ADS)

    Wood, Joshua D.; Doidge, Gregory P.; Carrion, Enrique A.; Koepke, Justin C.; Kaitz, Joshua A.; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Dong, Hefei; Haasch, Richard T.; Lyding, Joseph W.; Pop, Eric

    2015-02-01

    We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.

  1. An Overview of Carbon Nanotubes and Graphene for Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Zhu, Zanzan

    2017-07-01

    With the development of carbon nanomaterials in recent years, there has been an explosion of interests in using carbon nanotubes (CNTs) and graphene for developing new biosensors. It is believed that employing CNTs and graphene as sensor components can make sensors more reliable, accurate, and fast due to their remarkable properties. Depending on the types of target molecular, different strategies can be applied to design sensor device. This review article summarized the important progress in developing CNT- and graphene-based electrochemical biosensors, field-effect transistor biosensors, and optical biosensors. Although CNTs and graphene have led to some groundbreaking discoveries, challenges are still remained and the state-of-the-art sensors are far from a practical application. As a conclusion, future effort has to be made through an interdisciplinary platform, including materials science, biology, and electric engineering.

  2. Nanoscale phase change memory with graphene ribbon electrodes

    NASA Astrophysics Data System (ADS)

    Behnam, Ashkan; Xiong, Feng; Cappelli, Andrea; Wang, Ning C.; Carrion, Enrique A.; Hong, Sungduk; Dai, Yuan; Lyons, Austin S.; Chow, Edmond K.; Piccinini, Enrico; Jacoboni, Carlo; Pop, Eric

    2015-09-01

    Phase change memory (PCM) devices are known to reduce in power consumption as the bit volume and contact area of their electrodes are scaled down. Here, we demonstrate two types of low-power PCM devices with lateral graphene ribbon electrodes: one in which the graphene is patterned into narrow nanoribbons and the other where the phase change material is patterned into nanoribbons. The sharp graphene "edge" contacts enable switching with threshold voltages as low as ˜3 V, low programming currents (<1 μA SET and <10 μA RESET) and OFF/ON resistance ratios >100. Large-scale fabrication with graphene grown by chemical vapor deposition also enables the study of heterogeneous integration and that of variability for such nanomaterials and devices.

  3. Atomic resolution imaging of graphene by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Robertson, Alex W.; Warner, Jamie H.

    2013-05-01

    The atomic structure of a material influences its electronic, chemical, magnetic and mechanical properties. Characterising carbon nanomaterials, such as fullerenes, nanotubes and graphene, at the atomic level is challenging due to their chemical reactivity and low atomic mass. Transmission electron microscopy and scanning probe microscopy are two of the leading methods for imaging graphene at the atomic level. Here, we report on recent advances in atomic resolution imaging of graphene using aberration-corrected high resolution transmission electron microscopy and how it has revealed many of the structural deviations from the pristine monolayer form. Structures in graphene such as vacancy defects, edges, grain boundaries, linear chains, impurity dopants, layer number, layer stacking and bond rotations are explored.

  4. Self-assembly of biofunctional polymer on graphene nanoribbons.

    PubMed

    Reuven, Darkeyah G; Suggs, Kelvin; Williams, Michael D; Wang, Xiao-Qian

    2012-02-28

    Graphene's adhesive properties owing to inherent van der Waals interactions become increasingly relevant in the nanoscale regime. Polymer self-assembly via graphene-mediated noncovalent interactions offers a powerful tool for the creation of anisotropic nanopatterned systems. Here, we report the supramolecular self-assembly of biofunctional-modified poly(2-methoxystyrene) on graphene nanoribbons prepared by unzipping multiwalled carbon nanotubes. This approach promotes the glycol-modified polymer to self-assemble into structured nanopatterns with preserved bioactivity. The self-assembly is attributed to enhanced van der Waals interactions and the associated charge transfer from polymer to graphene. These findings demonstrate that the assembly yields a prospective route to novel nanomaterial systems.

  5. Annealing free, clean graphene transfer using alternative polymer scaffolds.

    PubMed

    Wood, Joshua D; Doidge, Gregory P; Carrion, Enrique A; Koepke, Justin C; Kaitz, Joshua A; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Dong, Hefei; Haasch, Richard T; Lyding, Joseph W; Pop, Eric

    2015-02-06

    We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.

  6. Polyelectrolyte-Induced Reduction of Exfoliated Graphite Oxide: A Facile Route to Synthesis of Soluble Graphene Nanosheets

    SciTech Connect

    Zhang, Sheng; Shao, Yuyan; Liao, Honggang; Engelhard, Mark H.; Yin, Geping; Lin, Yuehe

    2011-03-22

    Here we report that poly(diallyldimethylammonium chloride) (PDDA) acts as both a reducing agent and a stabilizer to prepare soluble graphene nanosheets from graphite oxide. The results of transmission electron microscopy, X-ray diffraction, X-ray photoeletron spectroscopy, atomic force microscopy, and fourier transform infrared indicated that graphite oxide was successfully reduced to graphene nanosheets which exhibited single-layer structure and high dispersion in various solvents. The reaction mechanism for PDDA-induced reduction of exfoliated graphite oxide was proposed. Furthermore, PDDA facilitated the in-situ growth of highly-dispersed Pt nanoparticles on the surface of graphene nanosheets to form Pt/graphene nanocomposites, which exhibited excellent catalytic activity towards formic acid oxidation. This work presents a facile and environmentally friendly approach to the synthesis of graphene nanosheets, opens up new possibility for preparing graphene and graphene-based nanomaterials for large-scale applications.

  7. Polyelectrolyte-induced reduction of exfoliated graphite oxide: a facile route to synthesis of soluble graphene nanosheets.

    PubMed

    Zhang, Sheng; Shao, Yuyan; Liao, Honggang; Engelhard, Mark H; Yin, Geping; Lin, Yuehe

    2011-03-22

    Here we report that poly(diallyldimethylammonium chloride) (PDDA) acts as both a reducing agent and a stabilizer to prepare soluble graphene nanosheets from graphite oxide. The results of transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and Fourier transform infrared indicated that graphite oxide was successfully reduced to graphene nanosheets which exhibited single-layer structure and high dispersion in various solvents. The reaction mechanism for PDDA-induced reduction of exfoliated graphite oxide was proposed. Furthermore, PDDA facilitated the in situ growth of highly dispersed Pt nanoparticles on the surface of graphene nanosheets to form Pt/graphene nanocomposites, which exhibited excellent catalytic activity toward formic acid oxidation. This work presents a facile and environmentally friendly approach to the synthesis of graphene nanosheets and opens up a new possibility for preparing graphene and graphene-based nanomaterials for large-scale applications.

  8. Synthesis and applications of carbon nanomaterials for energy generation and storage

    PubMed Central

    Notarianni, Marco; Liu, Jinzhang; Vernon, Kristy

    2016-01-01

    Summary The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage – the key to the portable electronics of the future. PMID:26925363

  9. Synthesis and applications of carbon nanomaterials for energy generation and storage.

    PubMed

    Notarianni, Marco; Liu, Jinzhang; Vernon, Kristy; Motta, Nunzio

    2016-01-01

    The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage - the key to the portable electronics of the future.

  10. Purity of graphene oxide determines its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Barbolina, I.; Woods, C. R.; Lozano, N.; Kostarelos, K.; Novoselov, K. S.; Roberts, I. S.

    2016-06-01

    Nanomaterials based on two-dimensional (2D) atomic crystals are considered to be very promising for various life-science and medical applications, from drug delivery to tissue modification. One of the most suitable materials for these purposes is graphene oxide (GO), thanks to a well-developed methods of production and water solubility. At the same time, its biological effect is still debated. Here we demonstrate that highly purified and thoroughly washed GO neither inhibited nor stimulated the growth of E.coli, ATCC25922; E.coli NCIMB11943 and S.aureus ATCC25923 at concentrations of up to 1 mg ml-1. Moreover, transmission electron microscopy (TEM) of GO exposed bacteria did not reveal any differences between GO exposed and not exposed populations. In contrast, a suspension of insufficiently purified GO behaved as an antibacterial material due to the presence of soluble acidic impurities, that could be removed by extended purification or neutralisation by alkaline substrates. A standardised protocol is proposed for the generation of clean GO, so it becomes suitable for biological experiments. Our findings emphasise the importance of GO purification status when dealing with biological systems as the true effect of material can be masked by the impact of impurities.

  11. Understanding the Dispersive Action of Nanocellulose for Carbon Nanomaterials.

    PubMed

    Hajian, Alireza; Lindström, Stefan B; Pettersson, Torbjörn; Hamedi, Mahiar M; Wågberg, Lars

    2017-03-08

    This work aims at understanding the excellent ability of nanocelluloses to disperse carbon nanomaterials (CNs) in aqueous media to form long-term stable colloidal dispersions without the need for chemical functionalization of the CNs or the use of surfactant. These dispersions are useful for composites with high CN content when seeking water-based, efficient, and green pathways for their preparation. To establish a comprehensive understanding of such dispersion mechanism, colloidal characterization of the dispersions has been combined with surface adhesion measurements using colloidal probe atomic force microscopy (AFM) in aqueous media. AFM results based on model surfaces of graphene and nanocellulose further suggest that there is an association between the nanocellulose and the CN. This association is caused by fluctuations of the counterions on the surface of the nanocellulose inducing dipoles in the sp(2) carbon lattice surface of the CNs. Furthermore, the charges on the nanocellulose will induce an electrostatic stabilization of the nanocellulose-CN complexes that prevents aggregation. On the basis of this understanding, nanocelluloses with high surface charge density were used to disperse and stabilize carbon nanotubes (CNTs) and reduced graphene oxide particles in water, so that further increases in the dispersion limit of CNTs could be obtained. The dispersion limit reached the value of 75 wt % CNTs and resulted in high electrical conductivity (515 S/cm) and high modulus (14 GPa) of the CNT composite nanopapers.

  12. Introduction of selectivity and specificity to graphene using an inimitable combination of molecular imprinting and nanotechnology.

    PubMed

    Roy, Ekta; Patra, Santanu; Tiwari, Ashutosh; Madhuri, Rashmi; Sharma, Prashant K

    2017-03-15

    Recently, the nanostructured modified molecularly imprinting polymer has created a great attention in research field due to its excellent properties such as high surface to volume ratio, low cost, and easy preparation/handling. Among the nanostructured materials, the carbonaceous material such as 'graphene' has attracted the tremendous attention of researchers owing to their fascinating electrical, thermal and physical properties. In this review article, we have tried to explore as well as compile the role of graphene-based nanomaterials in the fabrication of imprinted polymers. In other words, herein the recent efforts made to introduce selectivity in graphene-based nanomaterials were tried collected together. The major concern of this review article is focused on the sensing devices fabricated via a combination of graphene, graphene@nanoparticles, graphene@carbon nanotubes and molecularly imprinted polymers. Additionally, the combination of graphene and quantum dots was also included to explore the fluorescence properties of zero-band-gap graphene. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Selective Accelerated Proliferation of Malignant Breast Cancer Cells on Planar Graphene Oxide Films.

    PubMed

    Kenry; Chaudhuri, Parthiv Kant; Loh, Kian Ping; Lim, Chwee Teck

    2016-03-22

    Graphene nanomaterials have been actively investigated for biomedical and biological applications, including that of cancer. Despite progress made, most of such studies are conducted on dispersed graphene nanosheets in solution. Consequently, the use of planar graphene films, especially in cancer research, has not been fully explored. Here, we investigate the cellular interactions between the graphene material films and breast cancer cell lines, specifically the effects these films have on cellular proliferation, spreading area, and cytotoxicity. We demonstrate that the graphene oxide (GO) film selectively accelerates the proliferation of both metastatic (MDA-MB-231) and nonmetastatic (MCF-7) breast cancer cells, but not that of noncancer breast epithelial cells (MCF-10A). Contrastingly, this accelerated proliferation is not observed with the use of graphene (G) film. Moreover, GO induces negligible cytotoxicity on these cells. We suggest that the observed phenomena originate from the synergistic effect resulted from the high loading capacity and conformational change of cellular attachment proteins on the GO film, and the high amount of oxygenated groups present in the material. We anticipate that our findings can further shed light on the graphene-cancer cellular interactions and provide better understanding for the future design and application of graphene-based nanomaterials in cancer research.

  14. Nano-material and method of fabrication

    SciTech Connect

    Menchhofer, Paul A; Seals, Roland D; Howe, Jane Y; Wang, Wei

    2015-02-03

    A fluffy nano-material and method of manufacture are described. At 2000.times. magnification the fluffy nanomaterial has the appearance of raw, uncarded wool, with individual fiber lengths ranging from approximately four microns to twenty microns. Powder-based nanocatalysts are dispersed in the fluffy nanomaterial. The production of fluffy nanomaterial typically involves flowing about 125 cc/min of organic vapor at a pressure of about 400 torr over powder-based nano-catalysts for a period of time that may range from approximately thirty minutes to twenty-four hours.

  15. [Environmental behavior of graphene and its effect on the transport and fate of pollutants in environment].

    PubMed

    Ren, Wen-Jie; Teng, Ying

    2014-09-01

    Graphene is one of the most popular research topics in carbon nanomaterials. Because of its special physical and chemical properties, graphene will have wide applications. As the production and application amount is increasing, graphene will be inevitably released to the environment, resulting in risks of ecological environment and human health. It is of very vital significance for evaluating environmental risks of graphene scientifically and objectively to understand its environmental behavior and fate and explore its effect on the environmental behaviors of pollutants. This paper reviewed the environmental behavior of graphene, such as colloid properties and its stability in the aqueous environment and its transport through porous media. Additionally, the paper reviewed the effect of graphene on the transport and fate of pollutants. The interactions between graphene and heavy metals or organic compounds were especially discussed. Important topics should be explored including sorption mechanisms, interactions between graphene and soil components, influence of graphene on the transport and bioavailability of pollutants in environment, as well as approaches to quantifying graphene. The review might identify potential new ideas for further research in applications of graphene.

  16. Understanding Mechanical Response of Elastomeric Graphene Networks.

    PubMed

    Ni, Na; Barg, Suelen; Garcia-Tunon, Esther; Macul Perez, Felipe; Miranda, Miriam; Lu, Cong; Mattevi, Cecilia; Saiz, Eduardo

    2015-09-08

    Ultra-light porous networks based on nano-carbon materials (such as graphene or carbon nanotubes) have attracted increasing interest owing to their applications in wide fields from bioengineering to electrochemical devices. However, it is often difficult to translate the properties of nanomaterials to bulk three-dimensional networks with a control of their mechanical properties. In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features. The porous networks made of large reduced graphene oxide flakes (>20 μm) are superelastic and exhibit high energy absorption, showing much enhanced mechanical properties than those with small flakes (<2 μm). A better restoration of the graphitic nature also has a considerable effect. In comparison, microstructural differences, such as the foam architecture or the cell size have smaller or negligible effect on the mechanical response. The recoverability and energy adsorption depend on density with the latter exhibiting a minimum due to the interplay between wall fracture and friction during deformation. These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls.

  17. Understanding Mechanical Response of Elastomeric Graphene Networks

    PubMed Central

    Ni, Na; Barg, Suelen; Garcia-Tunon, Esther; Macul Perez, Felipe; Miranda, Miriam; Lu, Cong; Mattevi, Cecilia; Saiz, Eduardo

    2015-01-01

    Ultra-light porous networks based on nano-carbon materials (such as graphene or carbon nanotubes) have attracted increasing interest owing to their applications in wide fields from bioengineering to electrochemical devices. However, it is often difficult to translate the properties of nanomaterials to bulk three-dimensional networks with a control of their mechanical properties. In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features. The porous networks made of large reduced graphene oxide flakes (>20 μm) are superelastic and exhibit high energy absorption, showing much enhanced mechanical properties than those with small flakes (<2 μm). A better restoration of the graphitic nature also has a considerable effect. In comparison, microstructural differences, such as the foam architecture or the cell size have smaller or negligible effect on the mechanical response. The recoverability and energy adsorption depend on density with the latter exhibiting a minimum due to the interplay between wall fracture and friction during deformation. These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls. PMID:26348898

  18. The graphene/nucleic a