Catalytic conversion of aliphatic alcohols on carbon nanomaterials: The roles of structure and surface functional groups

NASA Astrophysics Data System (ADS)

Tveritinova, E. A.; Zhitnev, Yu. N.; Chernyak, S. A.; Arkhipova, E. A.; Savilov, S. V.; Lunin, V. V.

2017-03-01

Carbon nanomaterials with the structure of graphene and different compositions of the surface groups are used as catalysts for the conversion of C2-C4 aliphatic alcohols. The conversions of ethanol, propanol- 1, propanol-2, butanol-1, butanol-2, and tert-butanol on carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are investigated. Oxidized and nonoxidized multiwalled carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are synthesized. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning and transmission electronic microscopies, Brunauer-Emmett-Teller method, derivatographic analyses, and the pulsed microcatalytic method are used to characterize comprehensively the prepared catalysts. It was established that all of the investigated carbon nanomaterials (with the exception of nondoped carbon nanoflakes) are bifunctional catalysts for the conversion of aliphatic alcohols, and promote dehydration reactions with the formation of olefins and dehydrogenation reactions with the formation of aldehydes or ketones. Nanoflakes doped with nitrogen are inert with respect to secondary alcohols and tert-butanol. The role of oxygen-containing and nitrogen-containing surface groups, and of the geometrical structure of the carbon matrix of graphene nanocarbon materials in the catalytic conversion of aliphatic alcohols, is revealed. Characteristics of the conversion of aliphatic alcohols that are associated with their structure are identified.

CATALYTIC PROPERTIES OF SEMICONDUCTORS.

DTIC Science & Technology

SEMICONDUCTORS, CATALYSTS), (*CATALYSIS, REACTION KINETICS), (* SODIUM COMPOUNDS, TUNGSTATES), (*GALLIUM ALLOYS, ARSENIC ALLOYS), (*YTTERBIUM...COMPOUNDS, SILICIDES ), (*GERMANIUM, CATALYSIS), INTERNAL CONVERSION, EXCHANGE REACTIONS, HEAT OF ACTIVATION, THERMODYNAMICS, DEUTERIUM, POWDERS, SURFACES, HYDROGEN

Effects of Metal Composition and Ratio on Peptide-Templated Multimetallic PdPt Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merrill, Nicholas A.; Nitka, Tadeusz T.; McKee, Erik M.

It can be difficult to simultaneously control the size, composition, and morphology of metal nanomaterials under benign aqueous conditions. For this, bio-inspired approaches have become increasing popular due to their ability to stabilize a wide array of metal catalysts under ambient conditions. In this regard, we used the R5 peptide as a 3D template for the formation of PdPt bimetallic nanomaterials. Monometallic Pd and Pt nanomaterials have been shown to be highly reactive towards a variety of catalytic processes, but by forming bimetallic species, increased catalytic activity may be realized. The optimal metal-to-metal ratio was determined by varying the Pd:Ptmore » ratio to obtain the largest increase in catalytic activity. To better understand the morphology and the local atomic structure of the materials, the bimetallic PdPt nanomaterials were extensively studied using transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and pair distribution function analysis. The resulting PdPt materials were determined to form multicomponent nanostructures where the Pt component demonstrated varying degrees of oxidation based upon the Pd:Pt ratio. To test the catalytic reactivity of the materials, olefin hydrogenation was conducted which indicated a slight catalytic enhancement for the multicomponent materials. These results suggest a strong correlation between the metal ratio and the stabilizing biotemplate in controlling the final materials morphology, composition, and the interactions between the two metal species.« less

Effects of metal composition and ratio on peptide-templated multimetallic PdPt nanomaterials

DOE PAGES

Merrill, Nicholas A.; Nitka, Tadeusz T.; McKee, Erik M.; ...

2017-02-03

It can be difficult to simultaneously control the size, composition, and morphology of metal nanomaterials under benign aqueous conditions. For this, bioinspired approaches have become increasingly popular due to their ability to stabilize a wide array of metal catalysts under ambient conditions. In this regard, we used the R5 peptide as a three-dimensional template for formation of PdPt bimetallic nanomaterials. Monometallic Pd and Pt nanomaterials have been shown to be highly reactive toward a variety of catalytic processes, but by forming bimetallic species, increased catalytic activity may be realized. The optimal metal-to-metal ratio was determined by varying the Pd:Pt ratiomore » to obtain the largest increase in catalytic activity. To better understand the morphology and the local atomic structure of the materials, the bimetallic PdPt nanomaterials were extensively studied by transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and pair distribution function analysis. The resulting PdPt materials were determined to form multicomponent nanostructures where the Pt component demonstrated varying degrees of oxidation based upon the Pd:Pt ratio. To test the catalytic reactivity of the materials, olefin hydrogenation was conducted, which indicated a slight catalytic enhancement for the multicomponent materials. Finally, these results suggest a strong correlation between the metal ratio and the stabilizing biotemplate in controlling the final materials morphology, composition, and the interactions between the two metal species.« less

Techniques for Investigating Molecular Toxicology of Nanomaterials.

PubMed

Wang, Yanli; Li, Chenchen; Yao, Chenjie; Ding, Lin; Lei, Zhendong; Wu, Minghong

2016-06-01

Nanotechnology has been a rapidly developing field in the past few decades, resulting in the more and more exposure of nanomaterials to human. The increased applications of nanomaterials for industrial, commercial and life purposes, such as fillers, catalysts, semiconductors, paints, cosmetic additives and drug carriers, have caused both obvious and potential impacts on human health and environment. Nanotoxicology is used to study the safety of nanomaterials and has grown at the historic moment. Molecular toxicology is a new subdiscipline to study the interactions and impacts of materials at the molecular level. To better understand the relationship between the molecular toxicology and nanomaterials, this review summarizes the typical techniques and methods in molecular toxicology which are applied when investigating the toxicology of nanomaterials and include six categories: namely; genetic mutation detection, gene expression analysis, DNA damage detection, chromosomal aberration analysis, proteomics, and metabolomics. Each category involves several experimental techniques and methods.

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.

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.

RISK ASSESSMENT OF MANUFACTURED NANOMATERIAL: MORE THAN JUST SIZE

EPA Science Inventory

Nanotechnology is a dynamic and enabling technology capable of producing nano-scale materials with unique electrical, catalytic, thermal, mechanical, or imaging properties for a variety of applications. Nanomaterials may display unique toxicological properties and routes of expos...

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

A risk assessment framework for assessing metallic nanomaterials of environmental concern: aquatic exposure and behavior.

PubMed

O'Brien, Niall Joseph; Cummins, Enda J

2011-05-01

Nanomaterials are finding application in many different environmentally relevant products and processes due to enhanced catalytic, antimicrobial, and oxidative properties of materials at this scale. As the market share of nano-functionalized products increases, so too does the potential for environmental exposure and contamination. This study presents some exposure ranking methods that consider potential metallic nanomaterial surface water exposure and fate, due to nano-functionalized products, through a number of exposure pathways. These methods take into account the limited and disparate data currently available for metallic nanomaterials and apply variability and uncertainty principles, together with qualitative risk assessment principles, to develop a scientific ranking. Three exposure scenarios with three different nanomaterials were considered to demonstrate these assessment methods: photo-catalytic exterior paint (nano-scale TiO₂), antimicrobial food packaging (nano-scale Ag), and particulate-reducing diesel fuel additives (nano-scale CeO₂). Data and hypotheses from literature relating to metallic nanomaterial aquatic behavior (including the behavior of materials that may relate to nanomaterials in aquatic environments, e.g., metals, pesticides, surfactants) were used together with commercial nanomaterial characteristics and Irish natural aquatic environment characteristics to rank the potential concentrations, transport, and persistence behaviors within subjective categories. These methods, and the applied scenarios, reveal where data critical to estimating exposure and risk are lacking. As research into the behavior of metallic nanomaterials in different environments emerges, the influence of material and environmental characteristics on nanomaterial behavior within these exposure- and risk-ranking methods may be redefined on a quantitative basis. © 2010 Society for Risk Analysis.

Nanoscale chirality in metal and semiconductor nanoparticles

PubMed Central

Thomas, K. George

2016-01-01

The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided. PMID:27752651

Nanoscale chirality in metal and semiconductor nanoparticles.

PubMed

Kumar, Jatish; Thomas, K George; Liz-Marzán, Luis M

2016-10-18

The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided.

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. Copyright © 2011 Elsevier B.V. All rights reserved.

Bimetallic-catalyst-mediated syntheses of nanomaterials (nanowires, nanotubes, nanofibers, nanodots, etc) by the VQS (vapor-quasiliquid-solid, vapor- quasisolid-solid) growth mechanism

NASA Astrophysics Data System (ADS)

Mohammad, S. N.

2016-12-01

The enhanced synergistic, catalytic effect of bimetallic nanoparticles (BNPs), as compared to monometallic nanoparticles (NPs), on the nanomaterials (nanowires, nanotubes, nanodots, nanofibers, etc) synthesed by chemical vapor deposition has been investigated. A theoretical model for this catalytic effect and hence for nanomaterial growth, has been developed. The key element of the model is the diffusion of the nanomaterial source species through the nanopores of quasiliquid (quasisolid) BNP, rather than through the liquid or solid BNP, for nanomaterial growth. The role of growth parameters such as temperature, pressure and of the BNP material characteristics such as element mole fraction of BNP, has been studied. The cause of enhanced catalytic activity of BNPs as compared to NPs as a function of temperature has been explored. The dependence of growth rate on the nanomaterial diameter has also been examined. The calculated results have been extensively compared with available experiments. Experimental supports for the growth mechanism have been presented as well. Close correspondence between the calculated and experimental results attests to the validity of the proposed model. The wide applicability of the proposed model to nanowires, nanotubes, nanofibers, nanodots, etc suggests that it is general and has broad appeal.

Asymmetric Semiconductor Nanorod/Oxide Nanoparticle Hybrid Materials: Model Nanomaterials for Light-Activated Formation of Fuels from Sunlight. Formal Progress Report -- Award DE-FG02-05ER15753

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Neal R.

Executive Summary on Project Accomplishments: We focused our efforts for this project on the synthesis and characterization of semiconductor nanomaterials composed of semiconductor nanorods (NRs - e.g., CdSe, CdSe@CdS, CdS) with metal (Au, Pt, Co) or metal oxide (CoxOy) nanoparticle (NP) “tips.” These systems are attractive model systems where control of spatial, energetic and compositional features of both NRs and NP tips potentially enhances the efficiency of photogeneration and directional transport of charges, and photoelectrochemical conversion of sunlight to fuels. Synthetic methods to control material dimensions (20-200 nm in length), topology (one vs. two NP tips) and NR/NP tip compositionsmore » have been developed in the current project period (Pyun). We also achieved, for the first time in heterostructured nanorod materials, estimates of both valence band energies (E VB) and conduction band energies (E CB), using unique combinations of in vacuuo ultraviolet photoelectron spectroscopy (UPS, Armstrong), and waveguide spectroelectrochemistry (Saavedra), respectively. The spectroelectrochemical measurements in particular provide a unique path to estimation of E CB, and the distribution in E CB brought about by modification of NR composition. The combination of both approaches promises to be universally applicable to the characterization of energetics in nanomaterials of interest both for photovoltaic and sunlight-to-fuel photoelectrochemical assemblies.« less

Recent advances in noble metal based composite nanocatalysts: colloidal synthesis, properties, and catalytic applications.

PubMed

Xu, Yong; Chen, Lei; Wang, Xuchun; Yao, Weitang; Zhang, Qiao

2015-06-28

This Review article provides a report on progress in the synthesis, properties and catalytic applications of noble metal based composite nanomaterials. We begin with a brief discussion on the categories of various composite materials. We then present some important colloidal synthetic approaches to the composite nanostructures; here, major attention has been paid to bimetallic nanoparticles. We also introduce some important physiochemical properties that are beneficial from composite nanomaterials. Finally, we highlight the catalytic applications of such composite nanoparticles and conclude with remarks on prospective future directions.

Entrapping of fullerenes, nanotubes, and inorganic nanoparticles by a DNA-chitosan complex: a method for nanomaterials removal.

PubMed

Zinchenko, Anatoly A; Maeda, Noriko; Pu, Shengyan; Murata, Shizuaki

2013-05-07

We report a protocol for entrapping of various water-dispersed nanomaterials: fullerenes, multiwall carbon nanotubes, quantum dots (semiconductor nanoparticles), and gold nanorods, into a DNA-chitosan complex. In contrast to small-size nanomaterial particles, the bulky DNA-chitosan interpolyelectrolyte complex incorporating the dispersed nanomaterials can be easily separated from aqueous media by centrifugation, filtration, or decantation. While the removal of nanoparticles by centrifugation is equally efficient for every type of nanoparticles and reaches 100%, the higher efficiency of the nanomaterials removal by other two methods is favored by larger size of nanoparticles. The application of this entrapping protocol for removal of nanomaterials from water is discussed.

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.

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.

Greener production of nanomaterials and their applications in catalysis and environmental remediation

EPA Science Inventory

Metal nanomaterials have attracted considerable attention because of their unique magnetic, optical, electrical, and catalytic properties and their potential applications in nanoelectronics. There is great interest in synthesizing metal nanoparticles due to their extraordinary pr...

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes.

PubMed

Wei, Hui; Wang, Erkang

2013-07-21

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

A review on photocatalytic CO2 reduction using perovskite oxide nanomaterials

NASA Astrophysics Data System (ADS)

Zeng, Sheng; Kar, Piyush; Thakur, Ujwal Kumar; Shankar, Karthik

2018-02-01

As the search for efficient catalysts for CO2 photoreduction continues, nanostructured perovskite oxides have emerged as a class of high-performance photocatalytic materials. The perovskite oxide candidates for CO2 photoreduction are primarily nanostructured forms of titanates, niobates, tantalates and cobaltates. These materials form the focus of this review article because they are much sought-after due to their nontoxic nature, adequate chemical stability, and tunable crystal structures, bandgaps and surface energies. As compared to conventional semiconductors and nanomaterial catalysts, nanostructured perovskite oxides also exhibit an extended optical-absorption edge, longer charge carrier lifetimes, and favorable band-alignment with respect to reduction potential of activated CO2 and reduction products of the same. While CO2 reduction product yields of several hundred μmol-1 h-1 are observed with many types of perovskite oxide nanomaterials in stand-alone forms, yield of such quantities are not common with semiconductor nanomaterials of other types. In this review, we present current state-of-the-art synthesis methods to form perovskite oxide nanomaterials, and procedures to engineer their bandgaps. This review also presents a comprehensive summary and discussion on crystal structures, defect distribution, morphologies and electronic properties of the perovskite oxides, and correlation of these properties to CO2 photoreduction performance. This review offers researchers key insights for developing advanced perovskite oxides in order to further improve the yields of CO2 reduction products.

Antineoplastic Activity Comparison of Bovine Serum Albumin--Conjugated Sulfides Semiconductor Nanomaterials.

PubMed

Wang, Hua-Jie; Huang, Jing-Chun; Wu, Sha-Sha; Wang, Cai-Feng; Yu, Xue-Hong; Cao, Ying

2015-04-01

Although tumor is one of the most frequently occurring diseases and a leading cause of death, nanotechnology, one of the frontier sciences, is exhibiting its great potential to tumor treatments. The aim of this study was to design a facile and environmentally-friendly method to prepare bovine serum albumin-conjugated heavy metal sulfides nano-materials, including Ag2S, PbS and CdS. Here, bovine serum albumin was introduced in order to direct the synthesis of nano-materials by using its template effect and supply more sites for further modification in future. The crystal structure and morphology were analyzed by XRD and TEM, respectively. Additionally, the antineoplastic activity of nano-materials was compared by cell viability analysis, optical and electron microscopy observation after exposure of the human hepatoma cell line. The results showed that the inhibition effect of heavy metal sulfides on tumor cells was in the order of nano-PbS > bulk CdS > nano-Ag2S > nano-CdS > bulk PbS > bulk Ag2S. It could be concluded that heavy metal sulfides had significantly negative impact on human hepatoma cells growth but it could not be obviously generalized that nano-particles were always more effective to kill tumor cells than bulk materials. The size and surface reactivity might be the important factors causing the difference.

The laccase-like reactivity of manganese oxide nanomaterials for pollutant conversion: rate analysis and cyclic voltammetry.

PubMed

Wang, Xinghao; Liu, Jiaoqin; Qu, Ruijuan; Wang, Zunyao; Huang, Qingguo

2017-08-10

Nanostructured manganese oxides, e.g. MnO 2 , have shown laccase-like catalytic activities, and are thus promising for pollutant oxidation in wastewater treatment. We have systematically compared the laccase-like reactivity of manganese oxide nanomaterials of different crystallinity, including α-, β-, γ-, δ-, and ɛ-MnO 2 , and Mn 3 O 4 , with 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) and 17β-estradiol (E2) as the probing substrates. The reaction rate behaviors were examined with regard to substrate oxidation and oxygen reduction to evaluate the laccase-like catalysis of the materials, among which γ-MnO 2 exhibits the best performance. Cyclic voltammetry (CV) was employed to assess the six MnO x nanomaterials, and the results correlate well with their laccase-like catalytic activities. The findings help understand the mechanisms of and the factors controlling the laccase-like reactivity of different manganese oxides nanomaterials, and provide a basis for future design and application of MnO x -based catalysts.

Designing interfaces of hydrogenase-nanomaterial hybrids for efficient solar conversion.

PubMed

King, Paul W

2013-01-01

The direct conversion of sunlight into biofuels is an intriguing alternative to a continued reliance on fossil fuels. Natural photosynthesis has long been investigated both as a potential solution, and as a model for utilizing solar energy to drive a water-to-fuel cycle. The molecules and organizational structure provide a template to inspire the design of efficient molecular systems for photocatalysis. A clear design strategy is the coordination of molecular interactions that match kinetic rates and energetic levels to control the direction and flow of energy from light harvesting to catalysis. Energy transduction and electron-transfer reactions occur through interfaces formed between complexes of donor-acceptor molecules. Although the structures of several of the key biological complexes have been solved, detailed descriptions of many electron-transfer complexes are lacking, which presents a challenge to designing and engineering biomolecular systems for solar conversion. Alternatively, it is possible to couple the catalytic power of biological enzymes to light harvesting by semiconductor nanomaterials. In these molecules, surface chemistry and structure can be designed using ligands. The passivation effect of the ligand can also dramatically affect the photophysical properties of the semiconductor, and energetics of external charge-transfer. The length, degree of bond saturation (aromaticity), and solvent exposed functional groups of ligands can be manipulated to further tune the interface to control molecular assembly, and complex stability in photocatalytic hybrids. The results of this research show how ligand selection is critical to designing molecular interfaces that promote efficient self-assembly, charge-transfer and photocatalysis. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Metal-Insulator-Semiconductor Diode Consisting of Two-Dimensional Nanomaterials.

PubMed

Jeong, Hyun; Oh, Hye Min; Bang, Seungho; Jeong, Hyeon Jun; An, Sung-Jin; Han, Gang Hee; Kim, Hyun; Yun, Seok Joon; Kim, Ki Kang; Park, Jin Cheol; Lee, Young Hee; Lerondel, Gilles; Jeong, Mun Seok

2016-03-09

We present a novel metal-insulator-semiconductor (MIS) diode consisting of graphene, hexagonal BN, and monolayer MoS2 for application in ultrathin nanoelectronics. The MIS heterojunction structure was fabricated by vertically stacking layered materials using a simple wet chemical transfer method. The stacking of each layer was confirmed by confocal scanning Raman spectroscopy and device performance was evaluated using current versus voltage (I-V) and photocurrent measurements. We clearly observed better current rectification and much higher current flow in the MIS diode than in the p-n junction and the metal-semiconductor diodes made of layered materials. The I-V characteristic curve of the MIS diode indicates that current flows mainly across interfaces as a result of carrier tunneling. Moreover, we observed considerably high photocurrent from the MIS diode under visible light illumination.

Shape control of II-VI semiconductor nanomaterials.

PubMed

Kumar, Sandeep; Nann, Thomas

2006-03-01

Anisotropic II-VI semiconductor nanocrystals and nanoparticles have become important building blocks for (potential) nanotechnological applications. Even though a wide variety of differently shaped nanoparticles of this class can be prepared, the underlying mechanisms are mostly not fully understood. This Review article provides a brief overview of the currently studied shape-evolution mechanisms and the most prominent synthesis methods for such particles, with an aim to provide a fundamental understanding on how different morphologies evolve, and to function as a tool to aid in the preparation of specific nanocrystals.

Electrostatic Assembly of Nanomaterials for Hybrid Electrodes and Supercapacitors

NASA Astrophysics Data System (ADS)

Hammond, Paula

2015-03-01

Electrostatic assembly methods have been used to generate a range of new materials systems of interest for electrochemical energy and storage applications. Over the past several years, it has been demonstrated that carbon nanotubes, metals, metal oxides, polymeric nanomaterials, and biotemplated materials systems can be incorporated into ultrathin films to generate supercapacitors and battery electrodes that illustrate significant energy density and power. The unique ability to control the incorporation of such a broad range of materials at the nanometer length scale allows tailoring of the final properties of these unique composite systems, as well as the capability of creating complex micron-scale to nanoporous morphologies based on the scale of the nanomaterial that is absorbed within the structure, or the conditions of self-assembly. Recently we have expanded these capabilities to achieve new electrodes that are templated atop electrospun polmer fiber scaffolds, in which the polymer can be selectively removed to achieve highly porous materials. Spray-layer-by-layer and filtration methods of functionalized multiwall carbon nanotubes and polyaniline nanofibers enable the generation of electrode systems with unusually high surface. Incorporation of psuedocapacitive nanoparticles can enhance capacitive properties, and other catalytic or metallic nanoparticles can be implemented to enhance electrochemical or catalytic function.

Nanomaterials and Water Purification: Opportunities and Challenges

NASA Astrophysics Data System (ADS)

Savage, Nora; Diallo, Mamadou S.

2005-10-01

Advances in nanoscale science and engineering suggest that many of the current problems involving water quality could be resolved or greatly ameliorated using nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes and nanoparticle enhanced filtration among other products and processes resulting from the development of nanotechnology. Innovations in the development of novel technologies to desalinate water are among the most exciting and promising. Additionally, nanotechnology-derived products that reduce the concentrations of toxic compounds to sub-ppb levels can assist in the attainment of water quality standards and health advisories. This article gives an overview of the use of nanomaterials in water purification. We highlight recent advances on the development of novel nanoscale materials and processes for treatment of surface water, groundwater and industrial wastewater contaminated by toxic metal ions, radionuclides, organic and inorganic solutes, bacteria and viruses. In addition, we discuss some challenges associated with the development of cost effective and environmentally acceptable functional nanomaterials for water purification.

Design and characterization of nanomaterial-biomolecule conjugates

NASA Astrophysics Data System (ADS)

Yim, Tae-Jin

In the field of nanobiotechnology, nanoscale dimensions result in physical properties that differ from more conventional bulk material state. The integration of nanomaterials with biomolecules has begun to be used for unique physical properties, and for biological specific recognition, thereby leading to novel nanomaterial-biomolecule conjugates. The direction of this dissertation is to develop biocatalytic nanomaterial-biomolecule conjugates and to characterize them. For this, biological catalysts are employed to combine with nanomaterials. Two large parts include functional ization of nanomaterials with biomolecules and assembly of nanomaterials using a biological catalyst. First part of this thesis work is the exploration of the biocatalytic properties of nanomaterial-biomolecule conjugates. Si nanocolumns have higher surface area which leads more amount of biocatalytis immobilization than flat Si wafer with the same projected area. The enhanced activity of soybean peroxidase (SBP) immobilized onto Si nanocolumns as novel nanostructured supports is focused. Next, the catalytic activity of immobilized DNAzyme onto multiwalled carbon nanotubes (MWNTs) is compared to that in solution phase, and multiple turnovers are examined. The relationship between hybridization efficiency and activity is investigated as a function of surface density of DNAzyme on MWNTs. Then, cellular delivery of silica nanoparticle-protein conjugates is visually confirmed and therefore the intracellular function of a protein delivered by silica nanoparticle-protein conjugates is proved. For one example of the intracellular function, stable SBP immobilized onto silica nanoparticles to activate a prodrug is demonstrated. Second part of this thesis work is the formation of nanostructured materials through the enzymatic assembly of single-walled carbon nanotubes (SWNTs). Enzymatic polymerization of a phenol compound is applied to the bridging of two or more SWNTs functionalized with phenol

Green synthesis of water soluble semiconductor nanocrystals and their applications

NASA Astrophysics Data System (ADS)

Wang, Ying

II-VI semiconductor nanomaterials, e.g. CdSe and CdTe, have attracted great attention over the past decades due to their fascinating optical and electrical properties. The research presented here focuses on aqueous semiconductor nanomaterials. The work can be generally divided into three parts: synthesis, property study and application. The synthetic work is devoted to develop new methods to prepare shape- and structure-controlled II-VI semiconductor nanocrystals including nanoparticles and nanowires. CdSe and CdSe CdS semiconductor nanocrystals have been synthesized using sodium citrate as a stabilizer. Upon prolonged illumination with visible light, photoluminescence quantum yield of those quantum dots can be enhanced up to 5000%. The primary reason for luminescence enhancement is considered to be the removing of specific surface states (photocorrosion) and the smoothing of the CdSe core surface (photoannealing). CdTe nanowires are prepared through self-organization of stabilizer-depleted CdTe nanoparticles. The dipolar-dipolar attraction is believed to be the driving force of nanowire formation. The rich surface chemistry of CdTe nanowire is reflected by the formation of silica shell with different morphologies when nanowires with different capping ligands are used. Te and Se nanowires are prepared by chemical decomposition of CdTe and CdSe nanoparticles in presence of an external chemical stimulus, EDTA. These results not only provide a new example of NP→NW transformation, but also lead to a better understanding of the molecular process occurring in the stabilizer-depleted nanoparticles. The applications of those semiconductor materials are primarily based on the construction of nano-structured ultrathin films with desirable functions by using layer-by-layer technique (LBL). We demonstrate that light-induced micro-scale multicolor luminescent patterns can be obtained on photoactivable CdSe/CdS nanoparticles thin films by combining the advantages of LBL as

Microbial synthesis of chalcogenide semiconductor nanoparticles: a review.

PubMed

Jacob, Jaya Mary; Lens, Piet N L; Balakrishnan, Raj Mohan

2016-01-01

Chalcogenide semiconductor quantum dots are emerging as promising nanomaterials due to their size tunable optoelectronic properties. The commercial synthesis and their subsequent integration for practical uses have, however, been contorted largely due to the toxicity and cost issues associated with the present chemical synthesis protocols. Accordingly, there is an immediate need to develop alternative environment-friendly synthesis procedures. Microbial factories hold immense potential to achieve this objective. Over the past few years, bacteria, fungi and yeasts have been experimented with as eco-friendly and cost-effective tools for the biosynthesis of semiconductor quantum dots. This review provides a detailed overview about the production of chalcogen-based semiconductor quantum particles using the inherent microbial machinery. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Morphological transformations of BNCO nanomaterials: Role of intermediates

NASA Astrophysics Data System (ADS)

Wang, B. B.; Qu, X. L.; Zhu, M. K.; Levchenko, I.; Baranov, O.; Zhong, X. X.; Xu, S.; Ostrikov, K.

2018-06-01

Highly controllable structural transformation of various doped carbon and boron nitride nanomaterials have been achieved with the perspective of their application in microelectronics, optoelectronics, energy devices and catalytic reactions. Specifically, the syntheses of one-dimensional (1D) boron and nitrogen co-doped tube-like carbon nanorods and 2D vertical carbon and oxygen co-doped boron nitride nanosheets on silicon coated with gold films in N2-H2 plasma was demonstrated. During the synthesis of nanomaterials, boron carbide was used as carbon and boron sources. The results of characterizations by scanning and transmission electron microscopes, as well as micro-Raman and X-ray photoelectron spectroscopes indicate that the formation of different nanomaterials relates to the growth temperature and quantity of boron carbide. Specifically, 1D tube-like carbon nanorods doped with boron and nitrogen are formed at ∼910 °C using a small quantity of boron carbide, while 2D vertical boron nitride nanosheets doped with carbon and oxygen are grown at ∼870 °C using a large quantity of boron carbide. These studies indicate that the behaviors of a reactive intermediate product B2O3 on surfaces of Au nanoparticles play an important role in the formation of different nanomaterials, i.e., whether the B2O3 molecules deposited on Au nanoparticles are desorbed mainly determines the formation of different nanomaterials. The formation of 2D vertical carbon and oxygen co-doped boron nitride nanosheets is related to the high growth rate of edges of nanosheets. Furthermore, the photoluminescence (PL) properties of 1D boron and nitrogen co-doped tube-like carbon nanorods and 2D vertical carbon and oxygen co-doped boron nitride nanosheets were studied at room temperature. The PL results show that all the nanomaterials generate the ultraviolet, blue, green and red PL bands, but the 2D vertical carbon and oxygen co-doped boron nitride nanosheets emit more and stronger PL bands than

Insights into biogenic and chemical production of inorganic nanomaterials and nanostructures.

PubMed

Faramarzi, Mohammad Ali; Sadighi, Armin

2013-03-01

The synthesis of inorganic nanomaterials and nanostructures by the means of diverse physical, chemical, and biological principles has been developed in recent decades. The nanoscale materials and structures creation continue to be an active area of researches due to the exciting properties of the resulting nanomaterials and their innovative applications. Despite physical and chemical approaches which have been used for a long time to produce nanomaterials, biological resources as green candidates that can replace old production methods have been focused in recent years to generate various inorganic nanoparticles (NPs) or other nanoscale structures. Cost-effective, eco-friendly, energy efficient, and nontoxic produced nanomaterials using diverse biological entities have been received increasing attention in the last two decades in contrast to physical and chemical methods owe using toxic solvents, generate unwanted by-products, and high energy consumption which restrict the popularity of these ways employed in nanometric science and engineering. In this review, the biosynthesis of gold, silver, gold-silver alloy, magnetic, semiconductor nanocrystals, silica, zirconia, titania, palladium, bismuth, selenium, antimony sulfide, and platinum NPs, using bacteria, actinomycetes, fungi, yeasts, plant extracts and also informational bio-macromolecules including proteins, polypeptides, DNA, and RNA have been reported extensively to mention the current status of the biological inorganic nanomaterial production. In other hand, two well-known wet chemical techniques, namely chemical reduction and sol-gel methods, used to produce various types of nanocrystalline powders, metal oxides, and hybrid organic-inorganic nanomaterials have presented. Copyright © 2012 Elsevier B.V. All rights reserved.

Aptamer-Modified Semiconductor Quantum Dots for Biosensing Applications

PubMed Central

Wen, Lin; Qiu, Liping; Wu, Yongxiang; Hu, Xiaoxiao; Zhang, Xiaobing

2017-01-01

Semiconductor quantum dots have attracted extensive interest in the biosensing area because of their properties, such as narrow and symmetric emission with tunable colors, high quantum yield, high stability and controllable morphology. The introduction of various reactive functional groups on the surface of semiconductor quantum dots allows one to conjugate a spectrum of ligands, antibodies, peptides, or nucleic acids for broader and smarter applications. Among these ligands, aptamers exhibit many advantages including small size, high chemical stability, simple synthesis with high batch-to-batch consistency and convenient modification. More importantly, it is easy to introduce nucleic acid amplification strategies and/or nanomaterials to improve the sensitivity of aptamer-based sensing systems. Therefore, the combination of semiconductor quantum dots and aptamers brings more opportunities in bioanalysis. Here we summarize recent advances on aptamer-functionalized semiconductor quantum dots in biosensing applications. Firstly, we discuss the properties and structure of semiconductor quantum dots and aptamers. Then, the applications of biosensors based on aptamer-modified semiconductor quantum dots by different signal transducing mechanisms, including optical, electrochemical and electrogenerated chemiluminescence approaches, is discussed. Finally, our perspectives on the challenges and opportunities in this promising field are provided. PMID:28788080

Aptamer-Modified Semiconductor Quantum Dots for Biosensing Applications.

PubMed

Wen, Lin; Qiu, Liping; Wu, Yongxiang; Hu, Xiaoxiao; Zhang, Xiaobing

2017-07-28

Semiconductor quantum dots have attracted extensive interest in the biosensing area because of their properties, such as narrow and symmetric emission with tunable colors, high quantum yield, high stability and controllable morphology. The introduction of various reactive functional groups on the surface of semiconductor quantum dots allows one to conjugate a spectrum of ligands, antibodies, peptides, or nucleic acids for broader and smarter applications. Among these ligands, aptamers exhibit many advantages including small size, high chemical stability, simple synthesis with high batch-to-batch consistency and convenient modification. More importantly, it is easy to introduce nucleic acid amplification strategies and/or nanomaterials to improve the sensitivity of aptamer-based sensing systems. Therefore, the combination of semiconductor quantum dots and aptamers brings more opportunities in bioanalysis. Here we summarize recent advances on aptamer-functionalized semiconductor quantum dots in biosensing applications. Firstly, we discuss the properties and structure of semiconductor quantum dots and aptamers. Then, the applications of biosensors based on aptamer-modified semiconductor quantum dots by different signal transducing mechanisms, including optical, electrochemical and electrogenerated chemiluminescence approaches, is discussed. Finally, our perspectives on the challenges and opportunities in this promising field are provided.

Biogenic nanomaterials from photosynthetic microorganisms.

PubMed

Jeffryes, Clayton; Agathos, Spiros N; Rorrer, Gregory

2015-06-01

The use of algal cell cultures represents a sustainable and environmentally friendly platform for the biogenic production of nanobiomaterials and biocatalysts. For example, advances in the production of biogeneic nanomaterials from algal cell cultures, such as crystalline β-chitin nanofibrils and gold and silver nanoparticles, could enable the 'green' production of biomaterials such as tissue-engineering scaffolds or drug carriers, supercapacitors and optoelectric materials. The in vivo functionalization, as well as newly demonstrated methods of production and modification, of biogenic diatom biosilica have led to the development of organic-inorganic hybrid catalytic systems as well as new biomaterials for drug delivery, biosensors and heavy-metal adsorbents. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Electrocatalytic interface based on novel carbon nanomaterials for advanced electrochemical sensors

DOE PAGES

Zhou, Ming; Guo, Shaojun

2015-07-17

The rapid development of nanoscience and nanotechnology provides new opportunities for the sustainable progress of nanoscale catalysts (i.e., nanocatalysts). The introduction of nanocatalysts into electronic devices implants their novel functions into electronic sensing systems, resulting in the testing of many advanced electrochemical sensors and the fabrication of some highly sensitive, selective, and stable sensing platforms. In this Review, we will summarize recent significant progress on exploring advanced carbon nanomaterials (such as carbon nanotubes, graphene, highly ordered mesoporous carbons, and electron cyclotron resonance sputtered nanocarbon film) as nanoscale electrocatalysts (i.e., nanoelectrocatalysts) for constructing the catalytic nanointerfaces of electronic devices to achievemore » high-sensitivity and high-selectivity electrochemical sensors. Furthermore, different mechanisms for the extraordinary and unique electrocatalytic activities of these carbon nanomaterials will be also highlighted, compared and discussed. An outlook on the future trends and developments in this area will be provided at the end. Notably, to elaborate the nature of carbon nanomaterial, we will mainly focus on the electrocatalysis of single kind of carbon materials rather than their hybrid composite materials. As a result, we expect that advanced carbon nanomaterials with unique electrocatalytic activities will continue to attract increasing research interest and lead to new opportunities in various fields of research.« less

Electrocatalytic interface based on novel carbon nanomaterials for advanced electrochemical sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Ming; Guo, Shaojun

The rapid development of nanoscience and nanotechnology provides new opportunities for the sustainable progress of nanoscale catalysts (i.e., nanocatalysts). The introduction of nanocatalysts into electronic devices implants their novel functions into electronic sensing systems, resulting in the testing of many advanced electrochemical sensors and the fabrication of some highly sensitive, selective, and stable sensing platforms. In this Review, we will summarize recent significant progress on exploring advanced carbon nanomaterials (such as carbon nanotubes, graphene, highly ordered mesoporous carbons, and electron cyclotron resonance sputtered nanocarbon film) as nanoscale electrocatalysts (i.e., nanoelectrocatalysts) for constructing the catalytic nanointerfaces of electronic devices to achievemore » high-sensitivity and high-selectivity electrochemical sensors. Furthermore, different mechanisms for the extraordinary and unique electrocatalytic activities of these carbon nanomaterials will be also highlighted, compared and discussed. An outlook on the future trends and developments in this area will be provided at the end. Notably, to elaborate the nature of carbon nanomaterial, we will mainly focus on the electrocatalysis of single kind of carbon materials rather than their hybrid composite materials. As a result, we expect that advanced carbon nanomaterials with unique electrocatalytic activities will continue to attract increasing research interest and lead to new opportunities in various fields of research.« less

Protein Adsorption onto Nanomaterials for the Development of Biosensors and Analytical Devices: A Review

PubMed Central

Bhakta, Samir A.; Evans, Elizabeth; Benavidez, Tomás E.; Garcia, Carlos D.

2014-01-01

An important consideration for the development of biosensors is the adsorption of the bio recognition element to the surface of a substrate. As the first step in the immobilization process, adsorption affects most immobilization routes and much attention is given into the research of this process to maximize the overall activity of the bio sensor. The use of nanomaterials, specifically nanoparticles and nanostructured films, offers advantageous properties that can be fine-tuned for interaction with specific proteins to maximize activity, minimize structural changes, and enhance the catalytic step. In the biosensor field, protein-nanomaterial interactions are an emerging trend that span across many disciplines. This review addresses recent publications about the proteins most frequently used, their most relevant characteristics, and the conditions required to adsorb them to nanomaterials. When relevant and available, subsequent analytical figures of merits are discussed for selected biosensors. The general trend amongst the research papers allows concluding that the use of nanomaterials has already provided significant improvements in the analytical performance of many biosensors and that this research field will continue to grow. PMID:25892065

Nanomaterials towards fabrication of cholesterol biosensors: Key roles and design approaches.

PubMed

Saxena, Urmila; Das, Asim Bikas

2016-01-15

Importance of cholesterol biosensors is already recognized in the clinical diagnosis of cardiac and brain vascular diseases as discernible from the enormous amount of research in this field. Nevertheless, the practical application of a majority of the fabricated cholesterol biosensors is ordinarily limited by their inadequate performance in terms of one or more analytical parameters including stability, sensitivity and detection limit. Nanoscale materials offer distinctive size tunable electronic, catalytic and optical properties which opened new opportunities for designing highly efficient biosensor devices. Incorporation of nanomaterials in biosensing devices has found to improve the electroactive surface, electronic conductivity and biocompatibility of the electrode surfaces which then improves the analytical performance of the biosensors. Here we have reviewed recent advances in nanomaterial-based cholesterol biosensors. Foremost, the diverse roles of nanomaterials in these sensor systems have been discussed. Later, we have exhaustively explored the strategies used for engineering cholesterol biosensors with nanotubes, nanoparticles and nanocomposites. Finally, this review concludes with future outlook signifying some challenges of these nanoengineered cholesterol sensors. Copyright © 2015 Elsevier B.V. All rights reserved.

Nanomaterial-Based Plasmon-Enhanced Infrared Spectroscopy.

PubMed

Yang, Xiaoxia; Sun, Zhipei; Low, Tony; Hu, Hai; Guo, Xiangdong; García de Abajo, F Javier; Avouris, Phaedon; Dai, Qing

2018-05-01

Surface-enhanced infrared absorption (SEIRA) has attracted increasing attention due to the potential of infrared spectroscopy in applications such as molecular trace sensing of solids, polymers, and proteins, specifically fueled by recent substantial developments in infrared plasmonic materials and engineered nanostructures. Here, the significant progress achieved in the past decades is reviewed, along with the current state of the art of SEIRA. In particular, the plasmonic properties of a variety of nanomaterials are discussed (e.g., metals, semiconductors, and graphene) along with their use in the design of efficient SEIRA configurations. To conclude, perspectives on potential applications, including single-molecule detection and in vivo bioassays, are presented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanomaterials-based enzyme electrochemical biosensors operating through inhibition for biosensing applications.

PubMed

Kurbanoglu, Sevinc; Ozkan, Sibel A; Merkoçi, Arben

2017-03-15

In recent years great progress has been made in applying nanomaterials to design novel biosensors. Use of nanomaterials offers to biosensing platforms exceptional optical, electronic and magnetic properties. Nanomaterials can increase the surface of the transducing area of the sensors that in turn bring an increase in catalytic behaviors. They have large surface-to-volume ratio, controlled morphology and structure that also favor miniaturization, an interesting advantage when the sample volume is a critical issue. Biosensors have great potential for achieving detect-to-protect devices: devices that can be used in detections of pollutants and other treating compounds/analytes (drugs) protecting citizens' life. After a long term focused scientific and financial efforts/supports biosensors are expected now to fulfill their promise such as being able to perform sampling and analysis of complex samples with interest for clinical or environment fields. Among all types of biosensors, enzymatic biosensors, the most explored biosensing devices, have an interesting property, the inherent inhibition phenomena given the enzyme-substrate complex formation. The exploration of such phenomena is making remarkably important their application as research and applied tools in diagnostics. Different inhibition biosensor systems based on nanomaterials modification has been proposed and applied. The role of nanomaterials in inhibition-based biosensors for the analyses of different groups of drugs as well as contaminants such as pesticides, phenolic compounds and others, are discussed in this review. This deep analysis of inhibition-based biosensors that employ nanomaterials will serve researchers as a guideline for further improvements and approaching of these devices to real sample applications so as to reach society needs and such biosensor market demands. Copyright © 2016 Elsevier B.V. All rights reserved.

Advanced nanomaterials

NASA Astrophysics Data System (ADS)

Titus, Elby; Ventura, João; Pedro Araújo, João; Campos Gil, João

2017-12-01

Nanomaterials provide a remarkably novel outlook to the design and fabrication of materials. The know-how of designing, modelling and fabrication of nanomaterials demands sophisticated experimental and analytical techniques. The major impact of nanomaterials will be in the fields of electronics, energy and medicine. Nanoelectronics hold the promise of improving the quality of life of electronic devices through superior performance, weight reduction and lower power consumption. New energy production systems based on hydrogen, solar and nuclear sources have also benefited immensely from nanomaterials. In modern medicine, nanomaterials research will have great impact on public health care due to better diagnostic methods and design of novel drugs.

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.

Functional Nanomaterials for Environmental Applications and Bioassemblies

NASA Astrophysics Data System (ADS)

Nguyen, Michelle Anne

The rational design of nanomaterials has yielded new technologies that have revolutionized numerous diverse fields. The work detailed herein first describes the application of photocatalytic nanomaterials towards the environmental remediation of harmful toxins. Specifically, a low-temperature solution-phase synthetic route for size-controlled Cu2O octahedra particles was developed, and these materials were evaluated as catalysts for the photocatalytic degradation of aromatic organic compounds. Moreover, cubic Cu2O/Pd composite structures were fabricated and demonstrated to be effective photocatalysts for the generation of H2 and the reductive dehalogenation of polychlorinated biphenyls, well-known carcinogens present at many contaminated sites around the world. This photocatalytic approach to environmental remediation exemplifies the adaptation of light-driven technologies and sustainable practices to energy-intensive catalytic systems. In addition, this work also investigates the organic/inorganic interface of peptide-mediated Au nanoparticles as a means to identify rational design principles for materials binding peptide sequences for the advancement of stimuli-responsive bionanoassemblies. Factors inherent to peptide sequences that can promote strong materials-binding affinity and/or effective nanoparticle stabilization capability were identified in order to progress biomimetic technologies. These findings were elucidated using a combinational approach of peptide binding experiments to Au in partnership with molecular dynamics simulations. Overall, this work demonstrates the growing applications of nanomaterials in remediation technologies and aids in the understanding of the origins of peptide material affinity and nanoparticle stabilization.

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.

Facile synthesis of gold nanomaterials with unusual crystal structures.

PubMed

Fan, Zhanxi; Huang, Xiao; Chen, Ye; Huang, Wei; Zhang, Hua

2017-11-01

Gold (Au) nanomaterials have attracted wide research attention, owing to their high chemical stability, promising catalytic properties, excellent biocompatibility, unique electronic structure and outstanding localized surface plasmon resonance (LSPR) absorption properties; all of which are closely related to their size and shape. Recently, crystal-phase-controlled synthesis of noble metal nanomaterials has emerged as a promising strategy to tune their physicochemical properties. This protocol describes the detailed experimental procedures for the crystal-phase-controlled syntheses of Au nanomaterials with unusual crystal structures under mild conditions. Briefly, pure hexagonal close-packed (hcp) Au square sheets (AuSSs) with a thickness of ∼2.4 nm are synthesized using a graphene-oxide-assisted method in which HAuCl 4 is reduced by oleylamine in a mixture of hexane and ethanol. By using pure hexane as the solvent, well-dispersed ultrathin hcp/face-centered cubic (fcc) Au nanowires with a diameter of ∼1.6 nm on graphene oxide can be obtained. Meanwhile, hcp/fcc Au square-like plates with a side length of 200-400 nm are prepared via the secondary growth of Au on the hcp AuSSs. Remarkably, hexagonal (4H) Au nanoribbons with a thickness of 2.0-6.0 nm can be synthesized with a one-pot colloidal method in which HAuCl 4 is reduced by oleylamine in a mixed solvent of hexane and 1,2-dichloropropane. It takes 17-37 h for the synthesis of these Au nanomaterials with unusual crystal structures. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) are used to characterize the resultant Au nanomaterials, which could have many promising applications, such as biosensing, near-IR photothermal therapy, catalysis and surface-enhanced Raman scattering (SERS).

Designing Selectivity in Metal-Semiconductor Nanocrystals: Synthesis, Characterization, and Self-Assembly

NASA Astrophysics Data System (ADS)

Pavlopoulos, Nicholas George

This dissertation contains six chapters detailing recent advances that have been made in the synthesis and characterization of metal-semiconductor hybrid nanocrystals (HNCs), and the applications of these materials. Primarily focused on the synthesis of well-defined II-VI semiconductor nanorod (NR) and tetrapod (TP) based constructs of interest for photocatalytic and solar energy applications, the research described herein discusses progress towards the realization of key design rules for the synthesis of functional semiconductor nanocrystals (NCs). As such, a blend of novel synthesis, advanced characterization, and direct application of heterostructured nanoparticles are presented. The first chapter is a review summarizing the design, synthesis, properties, and applications of multicomponent nanomaterials composed of disparate semiconductor and metal domains. By coupling two compositionally distinct materials onto a single nanocrystal, synergistic properties can arise that are not present in the isolated components, ranging from self-assembly to photocatalysis. For semiconductor nanomaterials, this was first realized in the ability to tune nanomaterial dimensions from 0-D quantum dot (QD) structures to cylindrical (NR) and branched (TP) structures by exploitation of advanced colloidal synthesis techniques and understandings of NC facet reactivities. The second chapter is focused on the synthesis and characterization of well-defined CdSe-seeded-CdS (CdSe CdS) NR systems synthesized by overcoating of wurtzite (W) CdSe quantum dots with W-CdS shells. 1-dimensional NRs have been interesting constructs for applications such as solar concentrators, optical gains, and photocatalysis. Through synthetic control over CdSe CdS NR systems, materials with small and large CdSe seeds were prepared, and for each seed size, multiple NR lengths were prepared. Through transient absorption studies, it was found that band alignment did not affect the efficiency of charge localization

Structure Design and Performance Tuning of Nanomaterials for Electrochemical Energy Conversion and Storage.

PubMed

Sheng, Tian; Xu, Yue-Feng; Jiang, Yan-Xia; Huang, Ling; Tian, Na; Zhou, Zhi-You; Broadwell, Ian; Sun, Shi-Gang

2016-11-15

The performance of nanomaterials in electrochemical energy conversion (fuel cells) and storage (secondary batteries) strongly depends on the nature of their surfaces. Designing the structure of electrode materials is the key approach to achieving better performance. Metal or metal oxide nanocrystals (NCs) with high-energy surfaces and open surface structures have attained significant attention in the past decade since such features possess intrinsically exceptional properties. However, they are thermodynamically metastable, resulting in a huge challenge in their shape-controlled synthesis. The tuning of material structure, design, and performance on the nanoscale for electrochemical energy conversion and storage has attracted extended attention over the past few years. In this Account, recent progress made in shape-controlled synthesis of nanomaterials with high-energy surfaces and open surface structures using both electrochemical methods and surfactant-based wet chemical route are reviewed. In fuel cells, the most important catalytic materials are Pt and Pd and their NCs with high-energy surfaces of convex or concave morphology. These exhibit remarkable activity toward electrooxidation of small organic molecules, such as formic acid, methanol, and ethanol and so on. In practical applications, the successful synthesis of Pt NCs with high-energy surfaces of small sizes (sub-10 nm) realized a superior high mass activity. The electrocatalytic performances have been further boosted by synergetic effects in bimetallic systems, either through surface decoration using foreign metal atoms or by alloying in which the high-index facet structure is preserved and the electronic structure of the NCs is altered. The intrinsic relationship of high electrocatalytic performance dependent on open structure and high-energy surface is also valid for (metal) oxide nanomaterials used in Li ion batteries (LIB). It is essential for the anode nanomaterials to have optimized structures to

Layered Double Hydroxide Nanoclusters: Aqueous, Concentrated, Stable, and Catalytically Active Colloids toward Green Chemistry.

PubMed

Tokudome, Yasuaki; Morimoto, Tsuyoshi; Tarutani, Naoki; Vaz, Pedro D; Nunes, Carla D; Prevot, Vanessa; Stenning, Gavin B G; Takahashi, Masahide

2016-05-24

Increasing attention has been dedicated to the development of nanomaterials rendering green and sustainable processes, which occur in benign aqueous reaction media. Herein, we demonstrate the synthesis of another family of green nanomaterials, layered double hydroxide (LDH) nanoclusters, which are concentrated (98.7 g/L in aqueous solvent), stably dispersed (transparent sol for >2 weeks), and catalytically active colloids of nano LDHs (isotropic shape with the size of 7.8 nm as determined by small-angle X-ray scattering). LDH nanoclusters are available as colloidal building blocks to give access to meso- and macroporous LDH materials. Proof-of-concept applications revealed that the LDH nanocluster works as a solid basic catalyst and is separable from solvents of catalytic reactions, confirming the nature of nanocatalysts. The present work closely investigates the unique physical and chemical features of this colloid, the formation mechanism, and the ability to act as basic nanocatalysts in benign aqueous reaction systems.

Chemical Functionalization, Self-Assembly, and Applications of Nanomaterials and Nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Tifeng; Yan, Xingbin; Balan, Lavinia

2014-01-01

This special issue addresses the research studies on chemical functionalization, self-assembly, and applications of nanomaterials and nanocomposites. It contains twentyfour articles including two reviews and twenty-two research articles. It is used to create new functional nanomaterials and nanocomposites with a variety of sizes and morphologies such as Zn/Al layered double hydroxide, tin oxide nanowires, FeOOH-modified anion resin, Au nanoclusters silica composite nanospheres, Ti-doped ZnO sol-composite films, TiO2/ZnO composite, graphene oxide nanocomposites, LiFePO4/C nanocomposites, and chitosan nanoparticles. These nanomaterials and nanocomposites have widespread applications in tissue engineering, antitumor, sensors, photoluminescence, electrochemical, and catalytic properties. In addition, this themed issue includes somemore » research articles about self-assembly systems covering organogels and Langmuir films. Furthermore, B. Blasiak et al. performed a literature survey on the recent advances in production, functionalization, toxicity reduction, and application of nanoparticles in cancer diagnosis, treatment, and treatment monitoring. P. Colson et al. performed a literature survey on the recent advances in nanosphere lithography due to its compatibility with wafer-scale processes as well as its potential to manufacture a wide variety of homogeneous one-, two-, or three-dimensional nanostructures.« less

One-dimensional TiO2 nanomaterials: preparation and catalytic applications.

PubMed

Wu, Yu; Yu, Jie; Liu, Hong-Mei; Xu, Bo-Qing

2010-10-01

This work reports on the syntheses of one-dimensional (1D) H2Ti3O7 materials (nanotubes, nanowires and their mixtures) by autoclaving anatase titania (Raw-TiO2) in NaOH-containing ethanol-water solutions, followed by washing with acid solution. The synthesized nanosized materials were characterized using XRD, TEM/HRTEM, BET and TG techniques. The autoclaving temperature (120-180 degrees C) and ethanol-to-water ratio (V(EtOH)/V(H2O) = 0/60 approximately 30/30) were shown to be critical to the morphology of H2Ti3O7 product. The obtained H2Ti3O7 nanostructures were calcined at 400-900 degrees C to prepare 1D-TiO2 nanomaterials. H2Ti3O7 nanotubes were converted to anatase nanorods while H2Ti3O7 nanowires to TiO2(B) nanowires after the calcination at 400 degrees C. The calcination at higher temperatures led to gradual decomposition of the wires to rods and phase transformation from TiO2(B) to anatase then to rutile. Photocatalytic degradation of methyl orange was conducted to compare the photocatalytic activity of these 1D materials. These 1D materials were used as new support to prepare Au/TiO2 catalysts for CO oxidation at 0 degrees C and 1,3-butadiene hydrogenation at 120 degrees C. For the CO oxidation reaction, Au particles supported on anatase nanorods derived from the H2Ti3O7 nanotubes (Au/W-180-400) were 1.6 times active that in Au/P25-TiO2, 4 times that in Au/Raw-TiO2, and 8 times that on TiO2(B) nanowires derived from the H2Ti3O7 nanotubes (Au/M-180-400). For the hydrogenation of 1,3-butadiene, however, the activity of Au particles in Au/M-180-400 was 3 times higher than those in Au/W-180-400 but similar to those in Au/P25-TiO2. These results demonstrate that the potential of 1D-TiO2 nanomaterials in catalysis is versatile.

Nanosensors and nanomaterials for monitoring glucose in diabetes

PubMed Central

Cash, Kevin J.; Clark, Heather A.

2010-01-01

Worldwide, diabetes is a rapidly growing problem that is managed at the individual level by monitoring and controlling blood glucose levels to minimize the negative effects of the disease. Because of limitations in diagnostic methods, significant research efforts are focused on developing improved methods to measure glucose. Nanotechnology has impacted these efforts by increasing the surface area of sensors, improving the catalytic properties of electrodes and providing nanoscale sensors. Herein, we discuss developments in the past several years on both nanosensors that directly measure glucose as well as nanomaterials that improve glucose sensor function. Finally, we discuss challenges that must be overcome to apply these developments in the clinic. PMID:20869318

Shape-selective synthesis of Sn(MoO4)2 nanomaterials for catalysis and supercapacitor applications.

PubMed

Sakthikumar, K; Ede, Sivasankara Rao; Mishra, Soumyaranjan; Kundu, Subrata

2016-06-07

Size and shape-selective Sn(MoO4)2 nanomaterials have been synthesized for the first time using a simple hydrothermal route by the reaction of Sn(ii) chloride salt with sodium molybdate in CTAB micellar media under stirring at 60 °C temperature for about three hours. Needle-like and flake-like Sn(MoO4)2 nanomaterials were synthesized by optimizing the CTAB to metal salt molar ratio and by controlling other reaction parameters. The eventual diameter and length of the nanoneedles are ∼100 ± 10 nm and ∼850 ± 100 nm respectively. The average diameter of the flakes is ∼250 ± 50 nm. The synthesized Sn(MoO4)2 nanomaterials can be used in two potential applications, namely, catalytic reduction of nitroarenes and as an anodic material in electrochemical supercapacitors. From the catalysis study, it was observed that the Sn(MoO4)2 nanomaterials could act as a potential catalyst for the successful photochemical reduction of nitroarenes into their respective aminoarenes within a short reaction time. From the supercapacitor study, it was observed that the Sn(MoO4)2 nanomaterials of different shapes show different specific capacitance (Cs) values and the highest Cs value was observed for Sn(MoO4)2 nanomaterials having a flake-like morphology. The highest Cs value observed was 109 F g(-1) at a scan rate of 5 mV s(-1) for the flake-like Sn(MoO4)2 nanomaterials. The capacitor shows an excellent long cycle life along with 70% retention of the Cs value, even after 4000 consecutive cycles at a current density of 8 mA cm(-2). Other than the applications in catalysis and supercapacitors, the synthesized nanomaterials can find further applications in photoluminescence, sensor and other energy-related devices.

Rational design and synthesis of efficient Carbon and/or Silica functional nanomaterials for electrocatalysis and nanomedicine

NASA Astrophysics Data System (ADS)

Da Silva, Rafael

In nanomaterials there is a strong correlation between structure and properties. Thus, the design and synthesis of nanomaterials with well-defined structures and morphology is essential in order to produce materials with not only unique but also tailorable properties. The unique properties of nanomaterials in turn can be taken advantage of to create materials and nanoscale devices that can help address important societal issues, such as meeting renewable energy sources and efficient therapeutic and diagnostic methods to cure a range of diseases. In this thesis, the different synthetic approaches I have developed to produce functional nanomaterials composed of earth-abundant elements (mainly carbon and silica) at low cost in a very sustainable manner are discussed. In Chapter 1, the fundamental properties of nanomaterials and their properties and potential applications in many areas are introduced. In chapter 2, a novel synthetic method that allows polymerization of polyaniline (PANI), a conducting polymer, inside cylindrical channel pores of nanoporous silica (SBA-15) is discussed. In addition, the properties of the III resulting conducting polymer in the confined nanochannel spaces of SBA-15, and more importantly, experimental demonstration of the use of the resulting hybrid material (PANI/SBA-15 material) as electocatalyst for electrooxidation reactions with good overpotential, close to zero, are detailed. In chapter 3, the synthetic approach discussed in Chapter 2 is further extended to afford nitrogen- and oxygen-doped mesoporous carbons. This is possible by pyrolysis of the PANI/SBA-15 composite materials under inert atmosphere, followed by etching away their silica framework. The high catalytic activity of resulting carbon-based materials towards oxygen reduction reaction despite they do not possess any metal dopants is also included. The potential uses of nanomaterials in areas such as nanomedicine need deep understanding of the biocompatibility/ toxicity of

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.

Application of nanomaterials in two-terminal resistive-switching memory devices

PubMed Central

Ouyang, Jianyong

2010-01-01

Nanometer materials have been attracting strong attention due to their interesting structure and properties. Many important practical applications have been demonstrated for nanometer materials based on their unique properties. This article provides a review on the fabrication, electrical characterization, and memory application of two-terminal resistive-switching devices using nanomaterials as the active components, including metal and semiconductor nanoparticles (NPs), nanotubes, nanowires, and graphenes. There are mainly two types of device architectures for the two-terminal devices with NPs. One has a triple-layer structure with a metal film sandwiched between two organic semiconductor layers, and the other has a single polymer film blended with NPs. These devices can be electrically switched between two states with significant different resistances, i.e. the ‘ON’ and ‘OFF’ states. These render the devices important application as two-terminal non-volatile memory devices. The electrical behavior of these devices can be affected by the materials in the active layer and the electrodes. Though the mechanism for the electrical switches has been in argument, it is generally believed that the resistive switches are related to charge storage on the NPs. Resistive switches were also observed on crossbars formed by nanotubes, nanowires, and graphene ribbons. The resistive switches are due to nanoelectromechanical behavior of the materials. The Coulombic interaction of transient charges on the nanomaterials affects the configurable gap of the crossbars, which results into significant change in current through the crossbars. These nanoelectromechanical devices can be used as fast-response and high-density memory devices as well. PMID:22110862

Enantioselective cellular uptake of chiral semiconductor nanocrystals

NASA Astrophysics Data System (ADS)

Martynenko, I. V.; Kuznetsova, V. A.; Litvinov, I. K.; Orlova, A. O.; Maslov, V. G.; Fedorov, A. V.; Dubavik, A.; Purcell-Milton, F.; Gun'ko, Yu K.; Baranov, A. V.

2016-02-01

The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

Layered double hydroxide-based nanomaterials as highly efficient catalysts and adsorbents.

PubMed

Li, Changming; Wei, Min; Evans, David G; Duan, Xue

2014-11-01

Layered double hydroxides (LDHs) are a class of anion clays consisting of brucite-like host layers and interlayer anions, which have attracted increasing interest in the fields of catalysis/adsorption. By virtue of the versatility in composition, morphology, and architecture of LDH materials, as well as their unique structural properties (intercalation, topological transformation, and self-assembly with other functional materials), LDHs display great potential in the design and fabrication of nanomaterials applied in photocatalysis, heterogeneous catalysis, and adsorption/separation processes. Taking advantage of the structural merits and various control synthesis strategies of LDHs, the active center structure (e.g., crystal facets, defects, geometric and electronic states, etc.) and macro-nano morphology can be facilely manipulated for specific catalytic/adsorbent processes with largely enhanced performances. In this review, the latest advancements in the design and preparation of LDH-based functional nanomaterials for sustainable development in catalysis and adsorption are summarized. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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.

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.

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.

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.

Nanosensors and nanomaterials for monitoring glucose in diabetes.

PubMed

Cash, Kevin J; Clark, Heather A

2010-12-01

Worldwide, diabetes is a rapidly growing problem that is managed at the individual level by monitoring and controlling blood glucose levels to minimize the negative effects of the disease. Because of limitations in diagnostic methods, significant research efforts are focused on developing improved methods to measure glucose. Nanotechnology has impacted these efforts by increasing the surface area of sensors, improving the catalytic properties of electrodes and providing nanoscale sensors. Here, we discuss developments in the past several years on both nanosensors that directly measure glucose and nanomaterials that improve glucose sensor function. Finally, we discuss challenges that must be overcome to apply these developments in the clinic. Copyright © 2010 Elsevier Ltd. All rights reserved.

Method of depositing wide bandgap amorphous semiconductor materials

DOEpatents

Ellis, Jr., Frank B.; Delahoy, Alan E.

1987-09-29

A method of depositing wide bandgap p type amorphous semiconductor materials on a substrate without photosensitization by the decomposition of one or more higher order gaseous silanes in the presence of a p-type catalytic dopant at a temperature of about 200.degree. C. and a pressure in the range from about 1-50 Torr.

Future prospects of luminescent nanomaterial based security inks: from synthesis to anti-counterfeiting applications

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Singh, Satbir; Gupta, Bipin Kumar

2016-07-01

Counterfeiting of valuable documents, currency and branded products is a challenging problem that has serious economic, security and health ramifications for governments, businesses and consumers all over the world. It is estimated that counterfeiting represents a multi-billion dollar underground economy with counterfeit products being produced on a large scale every year. Counterfeiting is an increasingly high-tech crime and calls for high-tech solutions to prevent and deter the acts of counterfeiting. The present review briefly outlines and addresses the key challenges in this area, including the above mentioned concerns for anti-counterfeiting applications. This article describes a unique combination of all possible kinds of security ink formulations based on lanthanide doped luminescent nanomaterials, quantum dots (semiconductor and carbon based), metal organic frameworks as well as plasmonic nanomaterials for their possible use in anti-counterfeiting applications. Moreover, in this review, we have briefly discussed and described the historical background of luminescent nanomaterials, basic concepts and detailed synthesis methods along with their characterization. Furthermore, we have also discussed the methods adopted for the fabrication and design of luminescent security inks, various security printing techniques and their anti-counterfeiting applications.

National Survey of Workplaces Handling and Manufacturing Nanomaterials, Exposure to and Health Effects of Nanomaterials, and Evaluation of Nanomaterial Safety Data Sheets.

PubMed

Kim, Jeongho; Yu, Il Je

2016-01-01

A national survey on workplace environment nanomaterial handling and manufacturing was conducted in 2014. Workplaces relevant to nanomaterials were in the order of TiO2 (91), SiO2 (88), carbon black (84), Ag (35), Al2O3 (35), ZnO (34), Pb (33), and CeO2 (31). The survey results indicated that the number of workplaces handling or manufacturing nanomaterials was 340 (0.27% of total 126,846) workplaces. The number of nanomaterials used and products was 546 (1.60 per company) and 583 (1.71 per company), respectively. For most workplaces, the results on exposure to hazardous particulate materials, including nanomaterials, were below current OELs, yet a few workplaces were above the action level. As regards the health status of workers, 9 workers were diagnosed with a suspected respiratory occupational disease, where 7 were recommended for regular follow-up health monitoring. 125 safety data sheets (SDSs) were collected from the nanomaterial-relevant workplaces and evaluated for their completeness and reliability. Only 4 CNT SDSs (3.2%) included the term nanomaterial, while most nanomaterial SDSs were not regularly updated and lacked hazard information. When taken together, the current analysis provides valuable national-level information on the exposure and health status of workers that can guide the next policy steps for nanomaterial management in the workplace.

National Survey of Workplaces Handling and Manufacturing Nanomaterials, Exposure to and Health Effects of Nanomaterials, and Evaluation of Nanomaterial Safety Data Sheets

PubMed Central

2016-01-01

A national survey on workplace environment nanomaterial handling and manufacturing was conducted in 2014. Workplaces relevant to nanomaterials were in the order of TiO2 (91), SiO2 (88), carbon black (84), Ag (35), Al2O3 (35), ZnO (34), Pb (33), and CeO2 (31). The survey results indicated that the number of workplaces handling or manufacturing nanomaterials was 340 (0.27% of total 126,846) workplaces. The number of nanomaterials used and products was 546 (1.60 per company) and 583 (1.71 per company), respectively. For most workplaces, the results on exposure to hazardous particulate materials, including nanomaterials, were below current OELs, yet a few workplaces were above the action level. As regards the health status of workers, 9 workers were diagnosed with a suspected respiratory occupational disease, where 7 were recommended for regular follow-up health monitoring. 125 safety data sheets (SDSs) were collected from the nanomaterial-relevant workplaces and evaluated for their completeness and reliability. Only 4 CNT SDSs (3.2%) included the term nanomaterial, while most nanomaterial SDSs were not regularly updated and lacked hazard information. When taken together, the current analysis provides valuable national-level information on the exposure and health status of workers that can guide the next policy steps for nanomaterial management in the workplace. PMID:27556041

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

Nanometals for Solar-to-Chemical Energy Conversion: From Semiconductor-Based Photocatalysis to Plasmon-Mediated Photocatalysis and Photo-Thermocatalysis.

PubMed

Meng, Xianguang; Liu, Lequan; Ouyang, Shuxin; Xu, Hua; Wang, Defa; Zhao, Naiqin; Ye, Jinhua

2016-08-01

Nanometal materials play very important roles in solar-to-chemical energy conversion due to their unique catalytic and optical characteristics. They have found wide applications from semiconductor photocatalysis to rapidly growing surface plasmon-mediated heterogeneous catalysis. The recent research achievements of nanometals are reviewed here, with regard to applications in semiconductor photocatalysis, plasmonic photocatalysis, and plasmonic photo-thermocatalysis. As the first important topic discussed here, the latest progress in the design of nanometal cocatalysts and their applications in semiconductor photocatalysis are introduced. Then, plasmonic photocatalysis and plasmonic photo-thermocatalysis are discussed. A better understanding of electron-driven and temperature-driven catalytic behaviors over plasmonic nanometals is helpful to bridge the present gap between the communities of photocatalysis and conventional catalysis controlled by temperature. The objective here is to provide instructive information on how to take the advantages of the unique functions of nanometals in different types of catalytic processes to improve the efficiency of solar-energy utilization for more practical artificial photosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-precision, large-domain three-dimensional manipulation of nano-materials for fabrication nanodevices

PubMed Central

2011-01-01

Nanoscaled materials are attractive building blocks for hierarchical assembly of functional nanodevices, which exhibit diverse performances and simultaneous functions. We innovatively fabricated semiconductor nano-probes of tapered ZnS nanowires through melting and solidifying by electro-thermal process; and then, as-prepared nano-probes can manipulate nanomaterials including semiconductor/metal nanowires and nanoparticles through sufficiently electrostatic force to the desired location without structurally and functionally damage. With some advantages of high precision and large domain, we can move and position and interconnect individual nanowires for contracting nanodevices. Interestingly, by the manipulating technique, the nanodevice made of three vertically interconnecting nanowires, i.e., diode, was realized and showed an excellent electrical property. This technique may be useful to fabricate electronic devices based on the nanowires' moving, positioning, and interconnecting and may overcome fundamental limitations of conventional mechanical fabrication. PMID:21794151

One‐Dimensional Earth‐Abundant Nanomaterials for Water‐Splitting Electrocatalysts

PubMed Central

Li, Jun

2016-01-01

Hydrogen fuel acquisition based on electrochemical or photoelectrochemical water splitting represents one of the most promising means for the fast increase of global energy need, capable of offering a clean and sustainable energy resource with zero carbon footprints in the environment. The key to the success of this goal is the realization of robust earth‐abundant materials and cost‐effective reaction processes that can catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with high efficiency and stability. In the past decade, one‐dimensional (1D) nanomaterials and nanostructures have been substantially investigated for their potential in serving as these electrocatalysts for reducing overpotentials and increasing catalytic activity, due to their high electrochemically active surface area, fast charge transport, efficient mass transport of reactant species, and effective release of gas produced. In this review, we summarize the recent progress in developing new 1D nanomaterials as catalysts for HER, OER, as well as bifunctional electrocatalysts for both half reactions. Different categories of earth‐abundant materials including metal‐based and metal‐free catalysts are introduced, with their representative results presented. The challenges and perspectives in this field are also discussed. PMID:28331791

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.

Gas-phase synthesis of semiconductor nanocrystals and its applications

NASA Astrophysics Data System (ADS)

Mandal, Rajib

Luminescent nanomaterials is a newly emerging field that provides challenges not only to fundamental research but also to innovative technology in several areas such as electronics, photonics, nanotechnology, display, lighting, biomedical engineering and environmental control. These nanomaterials come in various forms, shapes and comprises of semiconductors, metals, oxides, and inorganic and organic polymers. Most importantly, these luminescent nanomaterials can have different properties owing to their size as compared to their bulk counterparts. Here we describe the use of plasmas in synthesis, modification, and deposition of semiconductor nanomaterials for luminescence applications. Nanocrystalline silicon is widely known as an efficient and tunable optical emitter and is attracting great interest for applications in several areas. To date, however, luminescent silicon nanocrystals (NCs) have been used exclusively in traditional rigid devices. For the field to advance towards new and versatile applications for nanocrystal-based devices, there is a need to investigate whether these NCs can be used in flexible and stretchable devices. We show how the optical and structural/morphological properties of plasma-synthesized silicon nanocrystals (Si NCs) change when they are deposited on stretchable substrates made of polydimethylsiloxane (PDMS). Synthesis of these NCs was performed in a nonthermal, low-pressure gas phase plasma reactor. To our knowledge, this is the first demonstration of direct deposition of NCs onto stretchable substrates. Additionally, in order to prevent oxidation and enhance the luminescence properties, a silicon nitride shell was grown around Si NCs. We have demonstrated surface nitridation of Si NCs in a single step process using non?thermal plasma in several schemes including a novel dual-plasma synthesis/shell growth process. These coated NCs exhibit SiNx shells with composition depending on process parameters. While measurements including

A Facile synthesis of superparamagnetic Fe3O4 nanofibers with superior peroxidase-like catalytic activity for sensitive colorimetric detection of L-cysteine

NASA Astrophysics Data System (ADS)

Chen, Sihui; Chi, Maoqiang; Zhu, Yun; Gao, Mu; Wang, Ce; Lu, Xiaofeng

2018-05-01

Superaramagnetic Fe3O4 nanomaterials are good candidates as enzyme mimics due to their excellent catalytic activity, high stability and facile synthesis. However, the morphology of Fe3O4 nanomaterials has much influence on their enzyme-like catalytic activity. In this work, we have developed a simple polymer-assisted thermochemical reduction approach to prepare Fe3O4 nanofibers for peroxidase-like catalytic applications. The as-prepared Fe3O4 nanofibers show a higher catalytic activity than commercial Fe3O4 nanoparticles. The steady-state kinetic assay result shows that the Michaelis-Menten constant value of the as-obtained Fe3O4 nanofibers is similar to that of horseradish peroxidase (HRP), indicating their superior affinity to the 3,3‧,5,5‧-tetramethylbenzidine (TMB) and H2O2 substrate. Based on the outstanding catalytic activity, a sensing platform for the detection of L-cysteine has been performed and the limit of detection is as low as 0.028 μM. In addition, an excellent selectivity toward L-cysteine over other types of amino acids, glucose and metal ions has been achieved as well. This work offers an original means for the fabrication of superparamagnetic Fe3O4 nanofibers and demonstrates their delightful potential applications in the fields of biosensing, environmental monitoring, and medical diagnostics.

ZnO Nanostructures for Drug Delivery and Theranostic Applications.

PubMed

Martínez-Carmona, Marina; Gun'ko, Yurii; Vallet-Regí, María

2018-04-23

In the last two decades, zinc oxide (ZnO) semiconductor Quantum dots (QDs) have been shown to have fantastic luminescent properties, which together with their low-cost, low-toxicity and biocompatibility have turned these nanomaterials into one of the main candidates for bio-imaging. The discovery of other desirable traits such as their ability to produce destructive reactive oxygen species (ROS), high catalytic efficiency, strong adsorption capability and high isoelectric point, also make them promising nanomaterials for therapeutic and diagnostic functions. Herein, we review the recent progress on the use of ZnO based nanoplatforms in drug delivery and theranostic in several diseases such as bacterial infection and cancer.

ZnO Nanostructures for Drug Delivery and Theranostic Applications

PubMed Central

Martínez-Carmona, Marina

2018-01-01

In the last two decades, zinc oxide (ZnO) semiconductor Quantum dots (QDs) have been shown to have fantastic luminescent properties, which together with their low-cost, low-toxicity and biocompatibility have turned these nanomaterials into one of the main candidates for bio-imaging. The discovery of other desirable traits such as their ability to produce destructive reactive oxygen species (ROS), high catalytic efficiency, strong adsorption capability and high isoelectric point, also make them promising nanomaterials for therapeutic and diagnostic functions. Herein, we review the recent progress on the use of ZnO based nanoplatforms in drug delivery and theranostic in several diseases such as bacterial infection and cancer. PMID:29690644

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

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.

Immobilization of a molecular catalyst on carbon nanotubes for highly efficient electro-catalytic water oxidation.

PubMed

Li, Fusheng; Li, Lin; Tong, Lianpeng; Daniel, Quentin; Göthelid, Mats; Sun, Licheng

2014-11-21

Electrochemically driven water oxidation has been performed using a molecular water oxidation catalyst immobilized on hybrid carbon nanotubes and nano-material electrodes. A high turnover frequency (TOF) of 7.6 s(-1) together with a high catalytic current density of 2.2 mA cm(-2) was successfully obtained at an overpotential of 480 mV after 1 h of bulk electrolysis.

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.

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

Recent progress in boron nanomaterials

PubMed Central

Kondo, Takahiro

2017-01-01

Abstract Various types of zero, one, and two-dimensional boron nanomaterials such as nanoclusters, nanowires, nanotubes, nanobelts, nanoribbons, nanosheets, and monolayer crystalline sheets named borophene have been experimentally synthesized and identified in the last 20 years. Owing to their low dimensionality, boron nanomaterials have different bonding configurations from those of three-dimensional bulk boron crystals composed of icosahedra or icosahedral fragments. The resulting intriguing physical and chemical properties of boron nanomaterials are fascinating from the viewpoint of material science. Moreover, the wide variety of boron nanomaterials themselves could be the building blocks for combining with other existing nanomaterials, molecules, atoms, and/or ions to design and create materials with new functionalities and properties. Here, the progress of the boron nanomaterials is reviewed and perspectives and future directions are described. PMID:29152014

NIOSH field studies team assessment: Worker exposure to aerosolized metal oxide nanoparticles in a semiconductor fabrication facility.

PubMed

Brenner, Sara A; Neu-Baker, Nicole M; Eastlake, Adrienne C; Beaucham, Catherine C; Geraci, Charles L

2016-11-01

The ubiquitous use of engineered nanomaterials-particulate materials measuring approximately 1-100 nanometers (nm) on their smallest axis, intentionally engineered to express novel properties-in semiconductor fabrication poses unique issues for protecting worker health and safety. Use of new substances or substances in a new form may present hazards that have yet to be characterized for their acute or chronic health effects. Uncharacterized or emerging occupational health hazards may exist when there is insufficient validated hazard data available to make a decision on potential hazard and risk to exposed workers under condition of use. To advance the knowledge of potential worker exposure to engineered nanomaterials, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted an on-site field evaluation in collaboration with on-site researchers at a semiconductor research and development facility on April 18-21, 2011. The Nanomaterial Exposure Assessment Technique (2.0) was used to perform a complete exposure assessment. A combination of filter-based sampling and direct-reading instruments was used to identify, characterize, and quantify the potential for worker inhalation exposure to airborne alumina and amorphous silica nanoparticles associated with th e chemical mechanical planarization wafer polishing process. Engineering controls and work practices were evaluated to characterize tasks that might contribute to potential exposures and to assess existing engineering controls. Metal oxide structures were identified in all sampling areas, as individual nanoparticles and agglomerates ranging in size from 60 nm to >1,000 nm, with varying structure morphology, from long and narrow to compact. Filter-based samples indicated very little aerosolized material in task areas or worker breathing zone. Direct-reading instrument data indicated increased particle counts relative to background in the wastewater treatment area; however

Computational and Physical Analysis of Catalytic Compounds

NASA Astrophysics Data System (ADS)

Wu, Richard; Sohn, Jung Jae; Kyung, Richard

2015-03-01

Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

Engineering the bioelectrochemical interface using functional nanomaterials and microchip technique toward sensitive and portable electrochemical biosensors.

PubMed

Jia, Xiaofang; Dong, Shaojun; Wang, Erkang

2016-02-15

Electrochemical biosensors have played active roles at the forefront of bioanalysis because they have the potential to achieve sensitive, specific and low-cost detection of biomolecules and many others. Engineering the electrochemical sensing interface with functional nanomaterials leads to novel electrochemical biosensors with improved performances in terms of sensitivity, selectivity, stability and simplicity. Functional nanomaterials possess good conductivity, catalytic activity, biocompatibility and high surface area. Coupled with bio-recognition elements, these features can amplify signal transduction and biorecognition events, resulting in highly sensitive biosensing. Additionally, microfluidic electrochemical biosensors have attracted considerable attention on account of their miniature, portable and low-cost systems as well as high fabrication throughput and ease of scaleup. For example, electrochemical enzymetic biosensors and aptamer biosensors (aptasensors) based on the integrated microchip can be used for portable point-of-care diagnostics and environmental monitoring. This review is a summary of our recent progress in the field of electrochemical biosensors, including aptasensors, cytosensors, enzymatic biosensors and self-powered biosensors based on biofuel cells. We presented the advantages that functional nanomaterials and microfluidic chip technology bring to the electrochemical biosensors, together with future prospects and possible challenges. Copyright © 2015 Elsevier B.V. All rights reserved.

Fabrication of Pd and Pt Nanotubes and Their Catalytic Study on p-Nitrophenol Reduction

NASA Astrophysics Data System (ADS)

Wang, Yinan; Wang, Jiankang; Chen, JingYi

2018-03-01

Pd and Pt nanotubes were fabricated using self-assembled DC8,9PC lipid tubules under mild conditions at room temperature. Scan electron microscope (SEM) show the hollow and open-ended structures of prepared Pd and Pt nanotubes. The Pd and Pt nanotubes demonstrate both high catalytic activity toward p-nitrophenol reduction and excellent stability. This work has indicated the application potentials of lipid tubules in fabricating hollow metal nanomaterials.

Preparation and photo-catalytic activities of FeOOH/ZnO/MMT composite

NASA Astrophysics Data System (ADS)

Zhou, Yao; Liu, Fusheng; Yu, Shitao

2015-11-01

Montmorillonite (MMT) was used as the carrier for synthesis of FeOOH and FeOOH/ZnO nano-material. FeOOH and FeOOH/ZnO were synthesized by the aqueous solutions of Fe(NO3)3-HNO3 and Zn(NO3)2-NaOH/Fe(NO3)3-HNO3 with the carrier of montmorillonite respectively. Transmission electron-microscopy (TEM) and X-ray diffraction (XRD) were used to study the morphology form and structure of the nano-materials. TEM was also used to demonstrate that FeOOH/ZnO can be formed with the appropriate interface. According to UV-vis absorption spectra, FeOOH/ZnO has a better response to visible light than FeOOH and ZnO, which indicates there is some coupling effect between FeOOH and ZnO. Pentachlorophenol (PCP) was used as a representative organic pollutant to evaluate the photo-catalytic efficiency of the FeOOH/ZnO and FeOOH catalysts in visible light (λ > 400 nm). The photo-catalytic efficiency of FeOOH/ZnO/MMT is better than FeOOH/MMT. According to FTIR, changes of pH and TOC, the degradation mechanism was also discussed. PCP was degraded to aromatic ketone and chloro-hydrocarbon compounds and then to H2O, CO2 and HCl.

A new approach to light up the application of semiconductor nanomaterials for photoelectrochemical biosensors: using self-operating photocathode as a highly selective enzyme sensor.

PubMed

Wang, Guang-Li; Liu, Kang-Li; Dong, Yu-Ming; Wu, Xiu-Ming; Li, Zai-Jun; Zhang, Chi

2014-12-15

Due to the intrinsic hole oxidation reaction occurred on the photoanode surface, currently developed photoelectrochemical biosensors suffer from the interference from coexisting reductive species (acting as electron donor) and a novel design strategy of photoelectrode for photoelectrochemical detection is urgently required. In this paper, a self-operating photocathode based on CdS quantum dots sensitized three-dimensional (3D) nanoporous NiO was designed and created, which showed highly selective and reversible response to dissolved oxygen (acting as electron acceptor) in the electrolyte solution. Using glucose oxidase (GOD) as a biocatalyst, a novel photoelectrochemical sensor for glucose was developed. The commonly encountered interferents such as H2O2, ascorbic acid (AA), cysteine (Cys), dopamine (DA), etc., almost had no effect for the cathodic photocurrent of the 3D NiO/CdS electrode, though these substances were proved to greatly influence the photocurrent of photoanodes, which indicated greatly improved selectivity of the method. The method was applied to detect glucose in real samples including serum and glucose injections with satisfactory results. This study could provide a new train of thought on designing of self-operating photocathode in photoelectrochemical sensing, promoting the application of semiconductor nanomaterials in photoelectrochemistry. Copyright © 2014 Elsevier B.V. All rights reserved.

Enhanced Synthesis of Carbon Nanomaterials Using Acoustically Excited Methane Diffusion Flames

PubMed Central

Hou, Shuhn-Shyurng; Chen, Kuan-Ming; Yang, Zong-Yun; Lin, Ta-Hui

2015-01-01

Acoustically modulated methane jet diffusion flames were used to enhance carbon nanostructure synthesis. A catalytic nickel substrate was employed to collect the deposit materials at sampling position z = 10 mm above the burner exit. The fabrication of carbon nano-onions (CNOs) and carbon nanotubes (CNTs) was significantly enhanced by acoustic excitation at frequencies near the natural flickering frequency (ƒ = 20 Hz) and near the acoustically resonant frequency (ƒ = 90 Hz), respectively. At these characteristic frequencies, flow mixing was markedly enhanced by acoustic excitation, and a flame structure with a bright slender core flame was generated, which provided a favorable flame environment for the growth of carbon nanomaterials. The production rate of CNOs was high at 20 Hz (near the natural flickering frequency), at which the gas temperature was about 680 °C. Additionally, a quantity of CNTs was obtained at 70–95 Hz, near the acoustically resonant frequency, at which the gas temperature was between 665 and 830 °C. However, no carbon nanomaterials were synthesized at other frequencies. The enhanced synthesis of CNOs and CNTs is attributed to the strong mixing of the fuel and oxidizer due to the acoustic excitation at resonant frequencies. PMID:28793473

Quantitative analysis of doped/undoped ZnO nanomaterials using laser assisted atom probe tomography: Influence of the analysis parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amirifar, Nooshin; Lardé, Rodrigue, E-mail: rodrigue.larde@univ-rouen.fr; Talbot, Etienne

2015-12-07

In the last decade, atom probe tomography has become a powerful tool to investigate semiconductor and insulator nanomaterials in microelectronics, spintronics, and optoelectronics. In this paper, we report an investigation of zinc oxide nanostructures using atom probe tomography. We observed that the chemical composition of zinc oxide is strongly dependent on the analysis parameters used for atom probe experiments. It was observed that at high laser pulse energies, the electric field at the specimen surface is strongly dependent on the crystallographic directions. This dependence leads to an inhomogeneous field evaporation of the surface atoms, resulting in unreliable measurements. We showmore » that the laser pulse energy has to be well tuned to obtain reliable quantitative chemical composition measurements of undoped and doped ZnO nanomaterials.« less

How Do Enzymes 'Meet' Nanoparticles and Nanomaterials?

PubMed

Chen, Ming; Zeng, Guangming; Xu, Piao; Lai, Cui; Tang, Lin

2017-11-01

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.

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.

Toxicity evaluations of various carbon nanomaterials.

PubMed

Uo, Motohiro; Akasaka, Tsukasa; Watari, Fumio; Sato, Yoshinori; Tohji, Kazuyuki

2011-01-01

After the discovery of fullerene and carbon nanotubes, various carbon nanomaterials were discovered or synthesized. The carbon nanomaterials have remarkable properties, different from bulk materials with the same chemical composition, and are therefore useful for industrial applications. However, the toxicity of nanomaterials may also differ from that of the bulk materials; this difference poses a concern. The physical similarity of nanomaterials to asbestos has led to evaluations for toxicity by many researchers using various methods. In this review, we compile and compare the toxicity evaluations of each carbon nanomaterial.

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

Biological Surface Adsorption Index of Nanomaterials: Modelling Surface Interactions of Nanomaterials with Biomolecules.

PubMed

Chen, Ran; Riviere, Jim E

2017-01-01

Quantitative analysis of the interactions between nanomaterials and their surrounding environment is crucial for safety evaluation in the application of nanotechnology as well as its development and standardization. In this chapter, we demonstrate the importance of the adsorption of surrounding molecules onto the surface of nanomaterials by forming biocorona and thus impact the bio-identity and fate of those materials. We illustrate the key factors including various physical forces in determining the interaction happening at bio-nano interfaces. We further discuss the mathematical endeavors in explaining and predicting the adsorption phenomena, and propose a new statistics-based surface adsorption model, the Biological Surface Adsorption Index (BSAI), to quantitatively analyze the interaction profile of surface adsorption of a large group of small organic molecules onto nanomaterials with varying surface physicochemical properties, first employing five descriptors representing the surface energy profile of the nanomaterials, then further incorporating traditional semi-empirical adsorption models to address concentration effects of solutes. These Advancements in surface adsorption modelling showed a promising development in the application of quantitative predictive models in biological applications, nanomedicine, and environmental safety assessment of nanomaterials.

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

Inhibition of tafel kinetics for electrolytic hydrogen evolution on isolated micron scale electrocatalysts on semiconductor interfaces

DOE PAGES

Coridan, Robert H.; Schichtl, Zebulon G.; Sun, Tao; ...

2016-08-30

Semiconductor-liquid junctions are ubiquitous in photoelectrochemical approaches for solar-to-fuels energy conversion. Electrocatalysts are added to the interface to improve catalytic efficiency, but they can also impair the photovoltage-generating energetics of the electrode without appropriate microscopic organization of catalytically active area on the surface. This balance is more complicated when gas products are evolved, like hydrogen on water splitting electrodes. Discrete catalysts can be blocked by the gas liquid-solid boundary of a bubble stuck to the surface. Here, we study the kinetics of hydrogen evolution on semiconductor electrodes fabricated with an isolated, micronscale platinum electrocatalyst pad. Movies of in operando bubblemore » evolution were recorded with synchrotron-based high-speed x-ray phase-contrast imaging in a compatible electrochemical cell. The self-limited growth of a bubble residing on the isolated electrocatalyst was measured by tracking the evolution of the gas-liquid boundary through the sequence of images in the movie. As a result, the effect of pad size on the catalytic currents and the issues with reactant transport can be inferred from these dynamics.« less

Inhibition of tafel kinetics for electrolytic hydrogen evolution on isolated micron scale electrocatalysts on semiconductor interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coridan, Robert H.; Schichtl, Zebulon G.; Sun, Tao

Semiconductor-liquid junctions are ubiquitous in photoelectrochemical approaches for solar-to-fuels energy conversion. Electrocatalysts are added to the interface to improve catalytic efficiency, but they can also impair the photovoltage-generating energetics of the electrode without appropriate microscopic organization of catalytically active area on the surface. This balance is more complicated when gas products are evolved, like hydrogen on water splitting electrodes. Discrete catalysts can be blocked by the gas liquid-solid boundary of a bubble stuck to the surface. Here, we study the kinetics of hydrogen evolution on semiconductor electrodes fabricated with an isolated, micronscale platinum electrocatalyst pad. Movies of in operando bubblemore » evolution were recorded with synchrotron-based high-speed x-ray phase-contrast imaging in a compatible electrochemical cell. The self-limited growth of a bubble residing on the isolated electrocatalyst was measured by tracking the evolution of the gas-liquid boundary through the sequence of images in the movie. As a result, the effect of pad size on the catalytic currents and the issues with reactant transport can be inferred from these dynamics.« less

Evolution of biofunctional semiconductor nanocrystals: a calorimetric investigation.

PubMed

Ghosh, Debasmita; Mondal, Somrita; Roy, Chandra Nath; Saha, Abhijit

2013-12-14

Semiconductor nanomaterials have found numerous applications in optoelectronic device fabrication and in platforms for drug delivery and hyperthermia cancer treatment, and in various other biomedical fields because of their high photochemical stability and size-tunable photoluminescence (PL). However, little attention has been paid to exploring the energetics of formation of these semiconductor nanoparticles. We demonstrate that formation of nanocrystals with biofunctionalization supported by widely used groups, BSA and cysteine, is an exothermic spontaneous process driven by enthalpy. The whole energetics of the reaction shows that formation of smaller particles is favored with lower synthesis temperature. Further, it is shown that the thermodynamics of nanoparticle formation is strongly influenced by the conformation of the protein matrix. We also demonstrate that protein supported formation of nanocrystals is thermodynamically more favorable compared to that involving smaller organic thiol groups. The favorable enthalpy of formation compensates unfavorable entropy, resulting in favorable Gibbs free energy. Thus, this study can open up new avenues for establishing a thermodynamic basis for the design of nanosystems with new and tunable properties.

Synthesis, Characterization, and Catalytic Applications of Transition Metal Oxide/Carbonate Nanomaterials

NASA Astrophysics Data System (ADS)

Jin, Lei

2011-12-01

This thesis contains two parts: 1) Studies of novel synthesis methods and characterization of advanced functional manganese oxide octahedral molecular sieves (OMS) and their applications in Li/Air batteries, solvent free toluene oxidations, and ethane oxydehydrogenation (ODH) in the presence of CO2, recycling the green house gas. 2) Development of unique Ln2O2CO3 (Ln = rare earth) layered materials and ZnO/La2O2CO3 composites as clean energy biofuel catalysts. These parts are separated into five different focused topics included in this thesis. The first topic presents studies of catalytic activities of a single step synthesized gamma-MnO2 octahedral molecular sieve nano fiber in solvent free atmospheric oxidation of toluene with molecular oxygen. Solvent free atmospheric oxidation of toluene is a notoriously difficult liquid phase oxidation process due to the challenge of oxidizing sp³ hybridized carbon in inactive hydrocarbons. The synthesized gamma-MnO2 showed excellent catalytic activity and good selectivity under the mild atmospheric reflux system. Under optimized conditions, a 47.8% conversion of toluene, along with 57% selectivity of benzoic acid and 15% of benzaldehyde were obtained. The effects of reaction time, amount of catalyst and initiator, and the reusability of the catalyst were investigated. The second topic involves developing titanium containing gamma-MnO 2 (TM) hollow spheres as electrocatalysts in Li/Air Batteries. Li/air batteries have recently attracted interest because they have the largest theoretical specific energy (11,972 Wh.kg-1) among all practical electrochemical couples. In this study, unique hollow aspheric materials were prepared for the first time using a one-step synthesis method and fully characterized by various techniques. These prepared materials were found to have excellent electrocatalytic activation as cathode materials in lithium-air batteries with a very high specific capacity (up to 2.3 A.h/g of carbon). The third

Atomic Scale Analysis of the Enhanced Electro- and Photo-Catalytic Activity in High-Index Faceted Porous NiO Nanowires

NASA Astrophysics Data System (ADS)

Shen, Meng; Han, Ali; Wang, Xijun; Ro, Yun Goo; Kargar, Alireza; Lin, Yue; Guo, Hua; Du, Pingwu; Jiang, Jun; Zhang, Jingyu; Dayeh, Shadi A.; Xiang, Bin

2015-02-01

Catalysts play a significant role in clean renewable hydrogen fuel generation through water splitting reaction as the surface of most semiconductors proper for water splitting has poor performance for hydrogen gas evolution. The catalytic performance strongly depends on the atomic arrangement at the surface, which necessitates the correlation of the surface structure to the catalytic activity in well-controlled catalyst surfaces. Herein, we report a novel catalytic performance of simple-synthesized porous NiO nanowires (NWs) as catalyst/co-catalyst for the hydrogen evolution reaction (HER). The correlation of catalytic activity and atomic/surface structure is investigated by detailed high resolution transmission electron microscopy (HRTEM) exhibiting a strong dependence of NiO NW photo- and electrocatalytic HER performance on the density of exposed high-index-facet (HIF) atoms, which corroborates with theoretical calculations. Significantly, the optimized porous NiO NWs offer long-term electrocatalytic stability of over one day and 45 times higher photocatalytic hydrogen production compared to commercial NiO nanoparticles. Our results open new perspectives in the search for the development of structurally stable and chemically active semiconductor-based catalysts for cost-effective and efficient hydrogen fuel production at large scale.

Nanomaterials and Global Sustainability.

PubMed

Hamers, Robert J

2017-03-21

Nanomaterials provide tremendous opportunities to advance human welfare in many areas including energy storage, catalysis, photovoltaic energy conversion, environmental remediation, and agriculture. As nanomaterials become incorporated into commercial processes and consumer products in increasing amounts, it will be essential to develop an understanding of how these materials interact with the environment. The broad spectrum and complexity of nanomaterials drive a need for molecular-level design rules. Ultimately a grand challenge is to use the power of chemistry to ensure that nanoenabled technologies can come to fruition in an environmentally benign manner.

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...

Pathophysiologic mechanisms of biomedical nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Liming, E-mail: wangliming@ihep.ac.cn; Chen, Chunying, E-mail: chenchy@nanoctr.cn

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.more » 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. - Highlights: • Rapid protein adsorption onto nanomaterials that affects biomedical effects • Nanomaterials and their interaction with biological membrane, intracellular trafficking and specific cellular effects • Nanomaterials and their interaction with biological barriers • The signaling pathways mediated by nanomaterials and related biomedical effects • Novel techniques for studying translocation and biomedical effects of NMs.« less

Self-assembled nanomaterials for photoacoustic imaging

NASA Astrophysics Data System (ADS)

Wang, Lei; Yang, Pei-Pei; Zhao, Xiao-Xiao; Wang, Hao

2016-01-01

In recent years, extensive endeavors have been paid to construct functional self-assembled nanomaterials for various applications such as catalysis, separation, energy and biomedicines. To date, different strategies have been developed for preparing nanomaterials with diversified structures and functionalities via fine tuning of self-assembled building blocks. In terms of biomedical applications, bioimaging technologies are urgently calling for high-efficient probes/contrast agents for high-performance bioimaging. Photoacoustic (PA) imaging is an emerging whole-body imaging modality offering high spatial resolution, deep penetration and high contrast in vivo. The self-assembled nanomaterials show high stability in vivo, specific tolerance to sterilization and prolonged half-life stability and desirable targeting properties, which is a kind of promising PA contrast agents for biomedical imaging. Herein, we focus on summarizing recent advances in smart self-assembled nanomaterials with NIR absorption as PA contrast agents for biomedical imaging. According to the preparation strategy of the contrast agents, the self-assembled nanomaterials are categorized into two groups, i.e., the ex situ and in situ self-assembled nanomaterials. The driving forces, assembly modes and regulation of PA properties of self-assembled nanomaterials and their applications for long-term imaging, enzyme activity detection and aggregation-induced retention (AIR) effect for diagnosis and therapy are emphasized. Finally, we conclude with an outlook towards future developments of self-assembled nanomaterials for PA imaging.

Antimicrobial and biocompatible properties of nanomaterials.

PubMed

Ul-Islam, M; Shehzad, A; Khan, S; Khattak, W A; Ullah, M W; Park, J K

2014-01-01

The rapid development of drug-resistant characteristics in pathogenic viral, bacterial, and fungal species and the consequent spread of infectious diseases are currently receiving serious attention. Indeed, there is a pressing demand to explore novel materials and develop new strategies that can address these issues of serious concern. Nanomaterials are currently proving to be the most capable therapeutic agents to cope with such hazards. The exceptional physiochemical properties and impressive antimicrobial capabilities of nanoparticles have provoked their utilization in biomedical fields. Nanomaterials of both organic and inorganic nature have shown the capabilities of disrupting microbial cells through different mechanisms. Along with the direct influence on the microbial cell membrane, DNA and proteins, these nanomaterials produce reactive oxygen species (ROS) that damage cell components and viruses. Currently, a serious hazard associated with these antimicrobial nanomaterials is their toxicity to human and animal cells. Extensive studies have reported the dose, time, and cell-dependent toxicology of various nanomaterials, and some have shown excellent biocompatible properties. Nevertheless, there is still debate regarding the use of nanomaterials for medical applications. Therefore, in this review, the antimicrobial activities of various nanomaterials with details of their acting mechanisms were compiled. The relative toxic and biocompatible behavior of nanomaterials emphasized in this study provides information pertaining to their practical applicability in medical fields.

Self-assembled nanomaterials for photoacoustic imaging.

PubMed

Wang, Lei; Yang, Pei-Pei; Zhao, Xiao-Xiao; Wang, Hao

2016-02-07

In recent years, extensive endeavors have been paid to construct functional self-assembled nanomaterials for various applications such as catalysis, separation, energy and biomedicines. To date, different strategies have been developed for preparing nanomaterials with diversified structures and functionalities via fine tuning of self-assembled building blocks. In terms of biomedical applications, bioimaging technologies are urgently calling for high-efficient probes/contrast agents for high-performance bioimaging. Photoacoustic (PA) imaging is an emerging whole-body imaging modality offering high spatial resolution, deep penetration and high contrast in vivo. The self-assembled nanomaterials show high stability in vivo, specific tolerance to sterilization and prolonged half-life stability and desirable targeting properties, which is a kind of promising PA contrast agents for biomedical imaging. Herein, we focus on summarizing recent advances in smart self-assembled nanomaterials with NIR absorption as PA contrast agents for biomedical imaging. According to the preparation strategy of the contrast agents, the self-assembled nanomaterials are categorized into two groups, i.e., the ex situ and in situ self-assembled nanomaterials. The driving forces, assembly modes and regulation of PA properties of self-assembled nanomaterials and their applications for long-term imaging, enzyme activity detection and aggregation-induced retention (AIR) effect for diagnosis and therapy are emphasized. Finally, we conclude with an outlook towards future developments of self-assembled nanomaterials for PA imaging.

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. ...

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

Nanomaterials for In Vivo Imaging.

PubMed

Smith, Bryan Ronain; Gambhir, Sanjiv Sam

2017-02-08

In vivo imaging, which enables us to peer deeply within living subjects, is producing tremendous opportunities both for clinical diagnostics and as a research tool. Contrast material is often required to clearly visualize the functional architecture of physiological structures. Recent advances in nanomaterials are becoming pivotal to generate the high-resolution, high-contrast images needed for accurate, precision diagnostics. Nanomaterials are playing major roles in imaging by delivering large imaging payloads, yielding improved sensitivity, multiplexing capacity, and modularity of design. Indeed, for several imaging modalities, nanomaterials are now not simply ancillary contrast entities, but are instead the original and sole source of image signal that make possible the modality's existence. We address the physicochemical makeup/design of nanomaterials through the lens of the physical properties that produce contrast signal for the cognate imaging modality-we stratify nanomaterials on the basis of their (i) magnetic, (ii) optical, (iii) acoustic, and/or (iv) nuclear properties. We evaluate them for their ability to provide relevant information under preclinical and clinical circumstances, their in vivo safety profiles (which are being incorporated into their chemical design), their modularity in being fused to create multimodal nanomaterials (spanning multiple different physical imaging modalities and therapeutic/theranostic capabilities), their key properties, and critically their likelihood to be clinically translated.

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes

NASA Astrophysics Data System (ADS)

Yang, Jinhui; Cooper, Jason K.; Toma, Francesca M.; Walczak, Karl A.; Favaro, Marco; Beeman, Jeffrey W.; Hess, Lucas H.; Wang, Cheng; Zhu, Chenhui; Gul, Sheraz; Yano, Junko; Kisielowski, Christian; Schwartzberg, Adam; Sharp, Ian D.

2017-03-01

Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co3O4/Co(OH)2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co3O4 spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.

Advanced Nanomaterials for High-Efficiency Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 enoughmore » 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

Nano-material and method of fabrication

DOEpatents

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.

Catalytic Properties and Biomedical Applications of Cerium Oxide Nanoparticles

PubMed Central

Walkey, Carl; Das, Soumen; Seal, Sudipta; Erlichman, Joseph; Heckman, Karin; Ghibelli, Lina; Traversa, Enrico; McGinnis, James F.; Self, William T.

2014-01-01

Cerium oxide nanoparticles (Nanoceria) have shown promise as catalytic antioxidants in the test tube, cell culture models and animal models of disease. However given the reactivity that is well established at the surface of these nanoparticles, the biological utilization of Nanoceria as a therapeutic still poses many challenges. Moreover the form that these particles take in a biological environment, such as the changes that can occur due to a protein corona, are not well established. This review aims to summarize the existing literature on biological use of Nanoceria, and to raise questions about what further study is needed to apply this interesting catalytic material to biomedical applications. These questions include: 1) How does preparation, exposure dose, route and experimental model influence the reported effects of Nanoceria in animal studies? 2) What are the considerations to develop Nanoceria as a therapeutic agent in regards to these parameters? 3) What biological targets of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are relevant to this targeting, and how do these properties also influence the safety of these nanomaterials? PMID:26207185

Nanomaterials for Engineering Stem Cell Responses.

PubMed

Kerativitayanan, Punyavee; Carrow, James K; Gaharwar, Akhilesh K

2015-08-05

Recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. Synergistic interactions between nanomaterials and stem cell engineering offer numerous possibilities to address some of the daunting challenges in regenerative medicine, such as controlling trigger differentiation, immune reactions, limited supply of stem cells, and engineering complex tissue structures. Specifically, the interactions between stem cells and their microenvironment play key roles in controlling stem cell fate, which underlines therapeutic success. However, the interactions between nanomaterials and stem cells are not well understood, and the effects of the nanomaterials shape, surface morphology, and chemical functionality on cellular processes need critical evaluation. In this Review, focus is put on recent development in nanomaterial-stem cell interactions, with specific emphasis on their application in regenerative medicine. Further, the emerging technologies based on nanomaterials developed over the past decade for stem cell engineering are reviewed, as well as the potential applications of these nanomaterials in tissue regeneration, stem cell isolation, and drug/gene delivery. It is anticipated that the enhanced understanding of nanomaterial-stem cell interactions will facilitate improved biomaterial design for a range of biomedical and biotechnological applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling Engineered Nanomaterials (ENMs) Fate and ...

EPA Pesticide Factsheets

Under the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is required to perform new chemical reviews of engineered nanomaterials (ENMs) identified in pre-manufacture notices. However, environmental fate models developed for traditional contaminants are limited in their ability to simulate the environmental behavior of nanomaterials due to incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. We have updated the Water Quality Analysis Simulation Program (WASP), version S, to incorporate nanomaterials as an explicitly simulated state variable. WASPS now has the capability to simulate nanomaterial fate and transport in surface waters and sediments using heteroaggregation, the kinetic process governing the attachment of nanomaterials to particles and subsequently ENM distribution in the aqueous and sediment phases. Unlike dissolved chemicals which use equilibrium partition coefficients, heteroaggregation consists of a particle collision rate and an attachment efficiency ( lXhet) that generally acts as a one direction process. To demonstrate, we used a derived a het value from sediment attachment studies to parameterize WASP for simulation of multi walled carbon nanotube (MWCNT) transport in Brier Creek, a coastal plain river located in central eastern Georgia, USA and a tr

One-dimensional nanomaterials for energy storage

NASA Astrophysics Data System (ADS)

Chen, Cheng; Fan, Yuqi; Gu, Jianhang; Wu, Liming; Passerini, Stefano; Mai, Liqiang

2018-03-01

The search for higher energy density, safer, and longer cycling-life energy storage systems is progressing quickly. One-dimensional (1D) nanomaterials have a large length-to-diameter ratio, resulting in their unique electrical, mechanical, magnetic and chemical properties, and have wide applications as electrode materials in different systems. This article reviews the latest hot topics in applying 1D nanomaterials, covering both their synthesis and their applications. 1D nanomaterials can be grouped into the categories: carbon, silicon, metal oxides, and conducting polymers, and we structure our discussion accordingly. Then, we survey the unique properties and application of 1D nanomaterials in batteries and supercapacitors, and provide comments on the progress and advantages of those systems, paving the way for a better understanding of employing 1D nanomaterials for energy storage.

Microwave-assisted chemistry: synthetic applications for rapid assembly of nanomaterials and organics.

PubMed

Gawande, Manoj B; Shelke, Sharad N; Zboril, Radek; Varma, Rajender S

2014-04-15

The magic of microwave (MW) heating technique, termed the Bunsen burner of the 21st century, has emerged as a valuable alternative in the synthesis of organic compounds, polymers, inorganic materials, and nanomaterials. Important innovations in MW-assisted chemistry now enable chemists to prepare catalytic materials or nanomaterials and desired organic molecules, selectively, in almost quantitative yields and with greater precision than using conventional heating. By controlling the specific MW parameters (temperature, pressure, and ramping of temperature) and choice of solvents, researchers can now move into the next generation of advanced nanomaterial design and development. Microwave-assisted chemical reactions are now well-established practices in the laboratory setting although some controversy lingers as to how MW irradiation is able to enhance or influence the outcome of chemical reactions. Much of the discussion has focused on whether the observed effects can, in all instances, be rationalized by purely thermal Arrhenius-based phenomena (thermal microwave effects), that is, the importance of the rapid heating and high bulk reaction temperatures that are achievable using MW dielectric heating in sealed reaction vessels, or whether these observations can be explained by so-called "nonthermal" or "specific microwave" effects. In recent years, innovative and significant advances have occurred in MW hardware development to help delineate MW effects, especially the use of silicon carbide (SiC) reaction vessels and the accurate measurement of temperature using fiber optic (FO) temperature probes. SiC reactors appear to be good alternatives to MW transparent borosilicate glass, because of their high microwave absorptivity, and as such they serve as valuable tools to demystify the claimed magical MW effects. This enables one to evaluate the influence of the electromagnetic field on the specific chemical reactions, under truly identical conventional heating

Chemistry and catalysis at the surface of nanomaterials

NASA Astrophysics Data System (ADS)

White, Brian Edward

This thesis will delve into three main areas of nanomaterials research: (I) Designing, building, and utilizing a chemical vapor deposition (CVD) system for the growth of CNTs; (II) Aqueous suspensions of carbon nanotubes (CNT) solubilized by various surfactants, and the oxidative chemistry that can occur at CNT surfaces; (III) Catalytic CO oxidation over supported Cu2O nanoparticle systems. An introduction to nanomaterials in general, with a particular emphasis on carbon nanotubes and nanoparticles will be given in Chapter one. Chapter two provides a summary of common techniques used to grow carbon nanotubes, and introduces a new method we have developed. This method is based on previous chemical vapor deposition techniques, but uses liquids, specifically ethanol, as the carbon source. Using ethanol has several advantages, including ease of use and safety, as well as chemical benefits. Our new process affords long, aligned, single-walled nanotubes, with a relatively narrow diameter distribution. This method can also be used to grow CNTs across slits, which can then be studied spectroscopically. In Chapter three CNT-surfactant aqueous suspensions will be discussed in depth, including a new robust polymer surfactant. Poly(maleic acid/octyl vinyl ether) (PMAOVE) is stable over a large range of temperatures and pH values, and is well suited for the study of the oxidative chemistry that can occur on SWNT surfaces. Our aqueous suspensions were found to be quite stable by zeta potential studies and their emissive properties exhibited a pH dependence, quenching at higher concentrations of H+. We attribute this dependence to chemisorbed oxygen and its protonation at lower pH values. By heating the suspensions of SWNTs, O2 can be driven off, thus eliminating the dependence on pH. We also reproducibly add oxygen back into the system in the form of 1DeltaO2 , obtained from an endoperoxide. This method allows us to calculate the number of oxygen molecules needed for

Highly active catalytic Ru/TiO2 nanomaterials for continuous flow production of γ-valerolactone.

PubMed

Ouyang, Weiyi; Munoz-Batista, Mario; Fernandez-Garcia, Marcos; Luque, Rafael

2018-05-29

Green energy production from renewable sources is an attractive but challenging topic to face the likely energy crisis scenario in the future. In the current work, a series of versatile Ru/TiO2 catalysts were simply synthesized and employed in continuous flow catalytic transfer hydrogenation of industrially derived methyl levulinate biowaste (from Avantium Chemicals B.V.) to γ-valerolactone. Different analytical techniques were applied in the characterization of the as-synthesized catalysts, including XRD, SEM, EDX, TEM and XPS etc. The effects of various reaction conditions (e.g. temperature, concentration and flow rate) were investigated. Results suggested that optimum dispersion and distribution of Ru on the TiO2 surface could efficiently promote production of γ-valerolactone, with 5% Ru/TiO2 catalyst providing excelling catalytic performance and stability as compared to commercial Ru catalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Protection of inorganic semiconductors for sustained, efficient photoelectrochemical water oxidation

DOE PAGES

Lichterman, Michael F.; Sun, Ke; Hu, Shu; ...

2015-10-25

Small-band-gap (E g < 2 eV) semiconductors must be stabilized for use in integrated devices that convert solar energy into the bonding energy of a reduced fuel, specifically H 2 (g) or a reduced-carbon species such as CH 3 OH or CH 4 . To sustainably and scalably complete the fuel cycle, electrons must be liberated through the oxidation of water to O 2 (g). Strongly acidic or strongly alkaline electrolytes are needed to enable efficient and intrinsically safe operation of a full solar-driven water-splitting system. But, under water-oxidation conditions, the small-band-gap semiconductors required for efficient cell operation aremore » unstable, either dissolving or forming insulating surface oxides. Here, we describe herein recent progress in the protection of semiconductor photoanodes under such operational conditions. We specifically describe the properties of two protective overlayers, TiO 2 /Ni and NiO x , both of which have demonstrated the ability to protect otherwise unstable semiconductors for > 100 h of continuous solar-driven water oxidation when in contact with a highly alkaline aqueous electrolyte (1.0 M KOH(aq)). Furthermore, the stabilization of various semiconductor photoanodes is reviewed in the context of the electronic characteristics and a mechanistic analysis of the TiO 2 films, along with a discussion of the optical, catalytic, and electronic nature of NiO x films for stabilization of semiconductor photoanodes for water oxidation.« less

Assembly of ordered carbon shells on semiconducting nanomaterials

DOEpatents

Sutter, Eli Anguelova; Sutter, Peter Werner

2010-05-11

In some embodiments of the invention, encapsulated semiconducting nanomaterials are described. In certain embodiments the nanostructures described are semiconducting nanomaterials encapsulated with ordered carbon shells. In some aspects a method for producing encapsulated semiconducting nanomaterials is disclosed. In some embodiments applications of encapsulated semiconducting nanomaterials are described.

Assembly of ordered carbon shells on semiconducting nanomaterials

DOEpatents

Sutter, Eli Anguelova; Sutter, Peter Werner

2012-10-02

In some embodiments of the invention, encapsulated semiconducting nanomaterials are described. In certain embodiments the nanostructures described are semiconducting nanomaterials encapsulated with ordered carbon shells. In some aspects a method for producing encapsulated semiconducting nanomaterials is disclosed. In some embodiments applications of encapsulated semiconducting nanomaterials are described.

Probing the defects in nano-semiconductors using positrons

NASA Astrophysics Data System (ADS)

Nambissan, P. M. G.

2011-01-01

Positron annihilation spectroscopy (PAS) is a very useful tool to study the defect properties of nanoscale materials. The ability of thermalized positrons to diffuse over to the surfaces of nanocrystallites prior to annihilation helps to explore the disordered atomic arrangement over there and is very useful in understanding the structure and properties of nanomaterials. As examples, the results of studies on FeS2 nanorods and ZnS nanoparticles are presented. In semiconductor nanoparticles, there are positron trapping sites within the grains also and these are characterised by using appropriate models on the measured positron lifetimes. We have observed vivid changes in the measured positron lifetimes and Doppler broadened gamma ray spectral lineshapes during structural transformations prompted by substitutional effects in Mn2+-doped ZnS nanorods. Interestingly, the nanoparticles did not exhibit the transformation, implying the morphologies of the nanosystems playing a decisive role. Quantum confinement effect in CdS nanoparticles was another phenomenon that could be seen through positron annihilation experiments. Coincidence Doppler broadening measurements have been useful to identify the elemental environment around the vacancy clusters that trap positrons. Recent studies on nanocrystalline oxide and sulphide semiconductors are also discussed.

Cellulose Nanomaterials in Water Treatment Technologies

PubMed Central

Carpenter, Alexis Wells; de Lannoy, Charles François; Wiesner, Mark R.

2015-01-01

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. PMID:25837659

Nanomaterials for Cardiac Myocyte Tissue Engineering.

PubMed

Amezcua, Rodolfo; Shirolkar, Ajay; Fraze, Carolyn; Stout, David A

2016-07-19

Since their synthesizing introduction to the research community, nanomaterials have infiltrated almost every corner of science and engineering. Over the last decade, one such field has begun to look at using nanomaterials for beneficial applications in tissue engineering, specifically, cardiac tissue engineering. During a myocardial infarction, part of the cardiac muscle, or myocardium, is deprived of blood. Therefore, the lack of oxygen destroys cardiomyocytes, leaving dead tissue and possibly resulting in the development of arrhythmia, ventricular remodeling, and eventual heart failure. Scarred cardiac muscle results in heart failure for millions of heart attack survivors worldwide. Modern cardiac tissue engineering research has developed nanomaterial applications to combat heart failure, preserve normal heart tissue, and grow healthy myocardium around the infarcted area. This review will discuss the recent progress of nanomaterials for cardiovascular tissue engineering applications through three main nanomaterial approaches: scaffold designs, patches, and injectable materials.

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.

[Nanomaterials in cosmetics--present situation and future].

PubMed

Masunaga, Takuji

2014-01-01

Cosmetics are consumer products intended to contribute to increasing quality of life and designed for long-term daily use. Due to such features of cosmetics, they are required to ensure quality and safety at a high level, as well as to perform well, in response to consumers' demands. Recently, the technology associated with nanomaterials has progressed rapidly and has been applied to various products, including cosmetics. For example, nano-sized titanium dioxide has been formulated in sunscreen products in pursuit of improving its performance. As some researchers and media have expressed concerns about the safety of nanomaterials, a vague feeling of anxiety has been raised in society. In response to this concern, the Japan Cosmetic Industry Association (JCIA) has begun original research related to the safety assurance of nanomaterials formulated in cosmetics, to allow consumers to use cosmetics without such concerns. This paper describes the activities of the JCIA regarding safety research on nanomaterials, including a survey of the actual usage of nanomaterials in cosmetics, analysis of the existence of nanomaterials on the skin, and assessment of skin carcinogenicity of nano-sized titanium dioxide. It also describes the international status of safety assurance and regulation regarding nanomaterials in cosmetics.

Novel nano-semiconductor film layer supported nano-Pd Complex Nanostructured Catalyst Pd/Ⓕ-MeOx/AC for High Efficient Selective Hydrogenation of Phenol to Cyclohexanone.

PubMed

Si, Jiaqi; Ouyang, Wenbing; Zhang, Yanji; Xu, Wentao; Zhou, Jicheng

2017-04-28

Supported metal as a type of heterogeneous catalysts are the most widely used in industrial processes. High dispersion of the metal particles of supported catalyst is a key factor in determining the performance of such catalysts. Here we report a novel catalyst Pd/Ⓕ-MeO x /AC with complex nanostructured, Pd nanoparticles supported on the platelike nano-semiconductor film/activated carbon, prepared by the photocatalytic reduction method, which exhibited high efficient catalytic performance for selective hydrogenation of phenol to cyclohexanone. Conversion of phenol achieved up to more than 99% with a lower mole ratio (0.5%) of active components Pd and phenol within 2 h at 70 °C. The synergistic effect of metal nanoparticles and nano-semiconductors support layer and the greatly increasing of contact interface of nano-metal-semiconductors may be responsible for the high efficiency. This work provides a clear demonstration that complex nanostructured catalysts with nano-metal and nano-semiconductor film layer supported on high specific surface AC can yield enhanced catalytic activity and can afford promising approach for developing new supported catalyst.

Identifying the Atomic-Level Effects of Metal Composition on the Structure and Catalytic Activity of Peptide-Templated Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merrill, Nicholas A.; McKee, Erik M.; Merino, Kyle C.

2015-10-12

Bioinspired approaches for the formation of metallic nanomaterials have been extensively employed for a diverse range of applications including diagnostics and catalysis. These materials can often be used under sustainable conditions; however, it is challenging to control the material size, morphology, and composition simultaneously. Here we have employed the R5 peptide, which forms a 3D scaffold to direct the size and linear shape of bimetallic PdAu nanomaterials for catalysis. The materials were prepared at varying Pd:Au ratios to probe optimal compositions to achieve maximal catalytic efficiency. These materials were extensively characterized at the atomic level using transmission electron microscopy, extendedmore » X-ray absorption fine structure spectroscopy, and atomic pair distribution function analysis derived from high-energy X-ray diffraction patterns to provide highly resolved structural information. The results confirmed PdAu alloy formation, but also demonstrated that significant surface structural disorder was present. The catalytic activity of the materials was studied for olefin hydrogenation, which demonstrated enhanced reactivity from the bimetallic structures.These results present a pathway to the bioinspired production of multimetallic materials with enhanced properties, which can be assessed via a suite of characterization methods to fully ascertain structure/function relationships.« less

Nanomaterial-Based Electrochemical Biosensors and Bioassays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Guodong; Mao, Xun; Gurung, Anant

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.

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

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.

Biotechnological synthesis of functional nanomaterials.

PubMed

Lloyd, Jonathan R; Byrne, James M; Coker, Victoria S

2011-08-01

Biological systems, especially those using microorganisms, have the potential to offer cheap, scalable and highly tunable green synthetic routes for the production of the latest generation of nanomaterials. Recent advances in the biotechnological synthesis of functional nano-scale materials are described. These nanomaterials range from catalysts to novel inorganic antimicrobials, nanomagnets, remediation agents and quantum dots for electronic and optical devices. Where possible, the roles of key biological macromolecules in controlling production of the nanomaterials are highlighted, and also technological limitations that must be addressed for widespread implementation are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes

DOE PAGES

Yang, Jinhui; Cooper, Jason K.; Toma, Francesca M.; ...

2016-11-07

Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. We demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co 3 O 4 /Co(OH) 2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. Furthermore, these films comprise compact and continuous nanocrystalline Co 3 O 4more » spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH) 2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p + n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.« less

Environmental Risk Assessment of Nanomaterials

NASA Astrophysics Data System (ADS)

Bayramov, A. A.

In this paper, various aspects of modern nanotechnologies and, as a result, risks of nanomaterials impact on an environment are considered. This very brief review of the First International Conference on Material and Information Sciences in High Technologies (2007, Baku, Azerbaijan) is given. The conference presented many reports that were devoted to nanotechnology in biology and business for the developing World, formation of charged nanoparticles for creation of functional nanostructures, nanoprocessing of carbon nanotubes, magnetic and optical properties of manganese-phosphorus nanowires, ultra-nanocrystalline diamond films, and nanophotonics communications in Azerbaijan. The mathematical methods of simulation of the group, individual and social risks are considered for the purpose of nanomaterials risk reduction and remediation. Lastly, we have conducted studies at a plant of polymeric materials (and nanomaterials), located near Baku. Assessments have been conducted on the individual risk of person affection and constructed the map of equal isolines and zones of individual risk for a plant of polymeric materials (and nanomaterials).

Synthesis of urease hybrid nanoflowers and their enhanced catalytic properties.

PubMed

Somturk, Burcu; Yilmaz, Ismail; Altinkaynak, Cevahir; Karatepe, Aslıhan; Özdemir, Nalan; Ocsoy, Ismail

2016-05-01

Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to enhance catalytic activity and stability. Although stability of enzyme was accomplished with immobilization approaches, activity of the most of the enzymes was declined after immobilization. Herein, we synthesize the flower shaped-hybrid nanomaterials called hybrid nanoflower (HNF) consisting of urease enzyme and copper ions (Cu(2+)) and report a mechanistic elucidation of enhancement in both activity and stability of the HNF. We demonstrated how experimental factors influence morphology of the HNF. We proved that the HNF (synthesized from 0.02mgmL(-1) urease in 10mM PBS (pH 7.4) at +4°C) exhibited the highest catalytic activity of ∼2000% and ∼4000% when stored at +4°C and RT, respectively compared to free urease. The highest stability was also achieved by this HNF by maintaining 96.3% and 90.28% of its initial activity within storage of 30 days at +4°C and RT, respectively. This dramatically enhanced activity is attributed to high surface area, nanoscale-entrapped urease and favorable urease conformation of the HNF. The exceptional catalytic activity and stability properties of HNF can be taken advantage of to use it in fields of biomedicine and chemistry. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural properties of TiO2 nanomaterials

NASA Astrophysics Data System (ADS)

Kusior, Anna; Banas, Joanna; Trenczek-Zajac, Anita; Zubrzycka, Paulina; Micek-Ilnicka, Anna; Radecka, Marta

2018-04-01

The surface of solids is characterized by active, energy-rich sites that determine physicochemical interaction with gaseous and liquid media and possible applications in photocatalysis. The behavior of materials in such processes is related to their form and amount of various species, especially water and forms of oxygen adsorbed on the surface. The preparation of materials with controlled morphology, which includes modifications of the size, geometry, and composition, is currently an important way of optimizing properties, as many of them depend on not only the size and phase composition, but also on shape. Hydroxylated centers on the surface, which can be treated as trapping sites, are particularly significant. Water adsorbed on the surface bridging hydroxyl groups can distinctly modulate the properties of the surface of titania. The saturation of the surface with hydroxyl groups may improve the photocatalytic properties. TiO2 nanomaterials were obtained via different methods. SEM and TEM analysis were performed to study the morphology. The analysis of XRD and Raman data revealed a phase composition of obtained materials. To examine the surface properties, FTIR absorption spectra of TiO2 nanomaterials were recorded. The photocatalytic activity of titanium dioxide nanoparticles was investigated through the decomposition of methylene blue. It was demonstrated that each surface modification affects the amount of adsorbed hydroxyl groups. The different contributions of the two species to the ν(H2O) FTIR bands for different nanostructures result from the preparation conditions. It was noted that pre-adsorbed water (the surface-bridging hydroxyl) might significantly modulate the surface properties of the material. The increase in hydroxyl group density on the titanium dioxide surface enhances the effectiveness of the photocatalytic processes. It was demonstrated that flower-like titania obtained via hydrothermal synthesis exhibits the weakest catalytic activity, in

Production of bioelectricity, bio-hydrogen, high value chemicals and bioinspired nanomaterials by electrochemically active biofilms.

PubMed

Kalathil, Shafeer; Khan, Mohammad Mansoob; Lee, Jintae; Cho, Moo Hwan

2013-11-01

Microorganisms naturally form biofilms on solid surfaces for their mutual benefits including protection from environmental stresses caused by contaminants, nutritional depletion or imbalances. The biofilms are normally dangerous to human health due to their inherited robustness. On the other hand, a recent study suggested that electrochemically active biofilms (EABs) generated by electrically active microorganisms have properties that can be used to catalyze or control the electrochemical reactions in a range of fields, such as bioenergy production, bioremediation, chemical/biological synthesis, bio-corrosion mitigation and biosensor development. EABs have attracted considerable attraction in bioelectrochemical systems (BESs), such as microbial fuel cells and microbial electrolysis cells, where they act as living bioanode or biocathode catalysts. Recently, it was reported that EABs can be used to synthesize metal nanoparticles and metal nanocomposites. The EAB-mediated synthesis of metal and metal-semiconductor nanocomposites is expected to provide a new avenue for the greener synthesis of nanomaterials with high efficiency and speed than other synthetic methods. This review covers the general introduction of EABs, as well as the applications of EABs in BESs, and the production of bio-hydrogen, high value chemicals and bio-inspired nanomaterials. Copyright © 2013 Elsevier Inc. All rights reserved.

Multi-metal oxide ceramic nanomaterial

DOEpatents

O'Brien, Stephen; Liu, Shuangyi; Huang, Limin

2016-06-07

A convenient and versatile method for preparing complex metal oxides is disclosed. The method uses a low temperature, environmentally friendly gel-collection method to form a single phase nanomaterial. In one embodiment, the nanomaterial consists of Ba.sub.AMn.sub.BTi.sub.CO.sub.D in a controlled stoichiometry.

Graphene-based nanomaterials for nanobiotechnology and biomedical applications.

PubMed

Krishna, K Vijaya; Ménard-Moyon, Cécilia; Verma, Sandeep; Bianco, Alberto

2013-10-01

Graphene family nanomaterials are currently being extensively explored for applications in the field of nanotechnology. The unique intrinsic properties treasured in their simple molecular design and their ability to work in coherence with other existing nanomaterials make graphene family nanomaterials the most promising candidates for different types of applications. This review highlights the scope and utility of these multifaceted nanomaterials in nanobiotechnology and biomedicine. In a tandem approach, this review presents the smooth inclusion of these nanomaterials into existing designs for creating efficient working models at the nanoscale level as well as discussing their broad future possibilities.

Antibacterial properties and toxicity from metallic nanomaterials

PubMed Central

Vimbela, Gina V; Ngo, Sang M; Fraze, Carolyn; Yang, Lei; Stout, David A

2017-01-01

The era of antibiotic resistance is a cause of increasing concern as bacteria continue to develop adaptive countermeasures against current antibiotics at an alarming rate. In recent years, studies have reported nanoparticles as a promising alternative to antibacterial reagents because of their exhibited antibacterial activity in several biomedical applications, including drug and gene delivery, tissue engineering, and imaging. Moreover, nanomaterial research has led to reports of a possible relationship between the morphological characteristics of a nanomaterial and the magnitude of its delivered toxicity. However, conventional synthesis of nanoparticles requires harsh chemicals and costly energy consumption. Additionally, the exact relationship between toxicity and morphology of nanomaterials has not been well established. Here, we review the recent advancements in synthesis techniques for silver, gold, copper, titanium, zinc oxide, and magnesium oxide nanomaterials and composites, with a focus on the toxicity exhibited by nanomaterials of multidimensions. This article highlights the benefits of selecting each material or metal-based composite for certain applications while also addressing possible setbacks and the toxic effects of the nanomaterials on the environment. PMID:28579779

General Observation of Photocatalytic Oxygen Reduction to Hydrogen Peroxide by Organic Semiconductor Thin Films and Colloidal Crystals.

PubMed

Gryszel, Maciej; Sytnyk, Mykhailo; Jakešová, Marie; Romanazzi, Giuseppe; Gabrielsson, Roger; Heiss, Wolfgang; Głowacki, Eric Daniel

2018-04-25

Low-cost semiconductor photocatalysts offer unique possibilities for industrial chemical transformations and energy conversion applications. We report that a range of organic semiconductors are capable of efficient photocatalytic oxygen reduction to H 2 O 2 in aqueous conditions. These semiconductors, in the form of thin films, support a 2-electron/2-proton redox cycle involving photoreduction of dissolved O 2 to H 2 O 2 , with the concurrent photooxidation of organic substrates: formate, oxalate, and phenol. Photochemical oxygen reduction is observed in a pH range from 2 to 12. In cases where valence band energy of the semiconductor is energetically high, autoxidation competes with oxidation of the donors, and thus turnover numbers are low. Materials with deeper valence band energies afford higher stability and also oxidation of H 2 O to O 2 . We found increased H 2 O 2 evolution rate for surfactant-stabilized nanoparticles versus planar thin films. These results evidence that photochemical O 2 reduction may be a widespread feature of organic semiconductors, and open potential avenues for organic semiconductors for catalytic applications.

The applicability of chemical alternatives assessment for engineered nanomaterials.

PubMed

Hjorth, Rune; Hansen, Steffen Foss; Jacobs, Molly; Tickner, Joel; Ellenbecker, Michael; Baun, Anders

2017-01-01

The use of alternatives assessment to substitute hazardous chemicals with inherently safer options is gaining momentum worldwide as a legislative and corporate strategy to minimize consumer, occupational, and environmental risks. Engineered nanomaterials represent an interesting case for alternatives assessment approaches, because they can be considered both emerging "chemicals" of concern, as well as potentially safer alternatives to hazardous chemicals. However, comparing the hazards of nanomaterials to traditional chemicals or to other nanomaterials is challenging, and critical elements in chemical hazard and exposure assessment may have to be fundamentally altered to sufficiently address nanomaterials. The aim of this paper is to assess the overall applicability of alternatives assessment methods for nanomaterials and to outline recommendations to enhance their use in this context. The present paper focuses on the adaptability of existing hazard and exposure assessment approaches to engineered nanomaterials as well as strategies to design inherently safer nanomaterials. We argue that alternatives assessment for nanomaterials is complicated by the sheer number of nanomaterials possible. As a result, the inclusion of new data tools that can efficiently and effectively evaluate nanomaterials as substitutes is needed to strengthen the alternatives assessment process. However, we conclude that with additional tools to enhance traditional hazard and exposure assessment modules of alternatives assessment, such as the use of mechanistic toxicity screens and control banding tools, alternatives assessment can be adapted to evaluate engineered nanomaterials as potential substitutes for chemicals of concern and to ensure safer nanomaterials are incorporated in the design of new products. Integr Environ Assess Manag 2017;13:177-187. © 2016 SETAC. © 2016 SETAC.

Atomic Layer Deposition for the Modification and Creation of Nanomaterials

NASA Astrophysics Data System (ADS)

Needham, Erinn Christine

Atomic layer deposition (ALD) is a vapor-phase technique for the conformal deposition of material with sub-nanometer precision, making it an ideal process for modifying and even creating nanomaterials. The focus of this dissertation is the study of how ALD precursors interact with organic materials, namely polymers, to create selectively deposited nano-scale patterns and how ALD coatings modify biological responses to nanomaterials, namely carbon nanotubes (CNT), after inhalation. Nanoscale patterning is vital to the semiconductor industry. With features becoming smaller and more complex with each passing year, new techniques are required to meet the needs of the industry. The ability to selectively pattern a material onto a wafer is of particular interest for the replacement of costly etching steps. In the first half of this dissertation, a method for the selective deposition of nano-scale patterns is presented. Patterned polymers were used as sacrificial sponges to soak up ALD precursors for the creation of metal-oxide features. Meanwhile, deposition in areas without polymer was limited to the monolayer regime. Following infiltration, the saturated polymer was burned away and the precursor oxidized to form a metal oxide reproduction of the polymer pattern. Determining the reaction between the ALD precursor, trimethylaluminum, and polymer, poly(methyl methacrylate), helped to achieve patterning by informing the proper selection of reactor temperature as well as exposure and purge times. Using this technique, features from tens of nanometers to tens of microns were patterned uniformly and simultaneously across a 150 mm wafer. Finally, this technique was extended to pattern two different materials using only one patterned polymer layer. ALD was first used to deposit a metal oxide were there was no polymer. By selecting ALD precursors that do not react within or on top of the polymer, selective deposition of the first material was achieved. Following this, the

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

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...

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.

Photothermal-enhanced catalysis in core-shell plasmonic hierarchical Cu7S4 microsphere@zeolitic imidazole framework-8.

PubMed

Wang, Feifan; Huang, Yanjie; Chai, Zhigang; Zeng, Min; Li, Qi; Wang, Yuan; Xu, Dongsheng

2016-12-01

Conventional semiconductor photocatalysis based on band-edge absorption remains inefficient due to the limited harvesting of solar irradiation and the complicated surface/interface chemistry. Herein, novel photothermal-enhanced catalysis was achieved in a core-shell hierarchical Cu 7 S 4 nano-heater@ZIF-8 heterostructures via near-infrared localized surface plasmon resonance. Our results demonstrated that both the high surface temperature of the photothermal Cu 7 S 4 core and the close-adjacency of catalytic ZIF-8 shell contributed to the extremely enhanced catalytic activity. Under laser irradiation (1450 nm, 500 mW), the cyclocondensation reaction rate increased 4.5-5.4 fold compared to that of the process at room temperature, in which the 1.6-1.8 fold enhancement was due to the localized heating effect. The simulated sunlight experiments showed a photothermal activation efficiency (PTAE) of 0.07%, further indicating the validity of photothermal catalysis based on the plasmonic semiconductor nanomaterials. More generally, this approach provides a platform to improve reaction activity with efficient utilization of solar energy, which can be readily extended to other green-chemistry processes.

Creating new superconducting & semiconducting nanomaterials and investigating the effect of reduced dimensionality on their properties

NASA Astrophysics Data System (ADS)

Mishra, Sukhada

The field of nanomaterials has continued to attract researchers to understand the fundamentals and to investigate potential applications in the fields of semiconductor physics, microfabrication, nanomedicine, surface sciences etc. One of the most critical aspects of the nanomaterials research is to establish synthetic protocols, which can address the underlying product requirements of reproducibility, homogenous morphology and controlled elemental composition. We have focused our research in exploring synthetic routes for the synthesis of superconducting and semiconducting nanomaterials and analyze their structure---property relationship through detailed characterizations. The first part of dissertation is focused on the synthesis of superconducting FeSe nanostructures using catalyst assisted chemical vapor deposition (CVD) technique. The effect of catalyst---FeSe interphase on the d spacing of the FeSe nanostructures has been analyzed, and the internal pressure effect on the Tc has been investigated further through in depth characterizations. The emphasis of second part is on the development of a simple yet versatile protocol for the synthesis of vertically aligned nanorod arrays on conducting substrate by combining electron beam lithography technique with electrochemical deposition. The technique has been utilized to fabricate photovoltaic CdTe nanorod arrays on conducting substrate and further extended to devise CdS---CdTe nanorod arrays to create radial and lateral p---n junction assembly. Using photo---electrochemical analysis, it was observed that, the nanorod arrays yielded higher photo---electrochemical current compared to the thin film counterpart. The third part of dissertation describes the CVD protocol to synthesize multifunctional, dumbbell shaped Au---CoSe nanoparticles, which possess potential applications in ' theronostic' biological examinations.

Plasmon-Exciton Coupling Interaction for Surface Catalytic Reactions.

PubMed

Wang, Jingang; Lin, Weihua; Xu, Xuefeng; Ma, Fengcai; Sun, Mengtao

2018-05-01

In this review, we firstly reveal the physical principle of plasmon-exciton coupling interaction with steady absorption spectroscopy, and ultrafast transition absorption spectroscopy, based on the pump-prop technology. Secondly, we introduce the fabrication of electro-optical device of two-dimensional semiconductor-nanostructure noble metals hybrid, based on the plasmon-exciton coupling interactions. Thirdly, we introduce the applications of plasmon-exciton coupling interaction in the field of surface catalytic reactions. Lastly, the perspective of plasmon-exciton coupling interaction and applications closed this review. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aptamer-conjugated nanomaterials and their applications

PubMed Central

Yang, Liu; Ye, Mao; Yang, Ronghua; Fu, Ting; Chen, Yan; Wang, Kemin

2011-01-01

The combination of aptamers with novel nanomaterials, including nanomaterial-based aptamer bioconjugates. has attracted considerable interest and has led to a wide variety of applications. In this review, we discuss how a variety of nanomaterials, including gold, silica and magnetic nanoparticles, as well as carbon nanotubes, hydrogels, liposomes and micelles, have been used to functionalize aptamers for a variety of applications. These aptamer functionalized materials have led to advances in amplified biosensing, cancer cell-specific recognition, high-efficiency separation, and targeted drug delivery. PMID:22016112

Nanomaterials as stationary phases and supports in liquid chromatography.

PubMed

Beeram, Sandya R; Rodriguez, Elliott; Doddavenkatanna, Suresh; Li, Zhao; Pekarek, Allegra; Peev, Darin; Goerl, Kathryn; Trovato, Gianfranco; Hofmann, Tino; Hage, David S

2017-10-01

The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent immobilization, adsorption, entrapment, and the synthesis or direct development of nanomaterials as part of a chromatographic support. Nanomaterials have been used in many types of LC. These applications have included the reversed-phase, normal-phase, ion-exchange, and affinity modes of LC, as well as related methods such as chiral separations, ion-pair chromatography and hydrophilic interaction liquid chromatography. Both small and large analytes (e.g., dyes, drugs, amino acids, peptides and proteins) have been used to evaluate possible applications for these nanomaterial-based methods. The use of nanomaterials in columns, capillaries and planar chromatography has been considered as part of these efforts. Potential advantages of nanomaterials in these applications have included their good chemical and physical stabilities, the variety of interactions many nanomaterials can have with analytes, and their unique retention properties in some separation formats. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nano sulfide and oxide semiconductors as promising materials for studies by positron annihilation

NASA Astrophysics Data System (ADS)

Nambissan, P. M. G.

2013-06-01

A number of wide band gap sulfide and oxide semiconducting nanomaterial systems were investigated using the experimental techniques of positron lifetime and coincidence Doppler broadening measurements. The results indicated several features of the nanomaterial systems, which were found strongly related to the presence of vacancy-type defects and their clusters. Quantum confinement effects were displayed in these studies as remarkable changes in the positron lifetimes and the lineshape parameters around the same grain sizes below which characteristic blue shifts were observed in the optical absorption spectra. Considerable enhancement in the band gap and significant rise of the positron lifetimes were found occurring when the particle sizes were reduced to very low sizes. The results of doping or substitutions by other cations in semiconductor nanosystems were also interesting. Variously heat-treated TiO2 nanoparticles were studied recently and change of positron annihilation parameters across the anatase to rutile structural transition are carefully analyzed. Preliminary results of positron annihilation studies on Eu-doped CeO nanoparticles are also presented.

2D nanomaterials assembled from sequence-defined molecules

DOE PAGES

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

2017-10-21

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

Nanomaterial-Enabled Wearable Sensors for Healthcare.

PubMed

Yao, Shanshan; Swetha, Puchakayala; Zhu, Yong

2018-01-01

Highly sensitive wearable sensors that can be conformably attached to human skin or integrated with textiles to monitor the physiological parameters of human body or the surrounding environment have garnered tremendous interest. Owing to the large surface area and outstanding material properties, nanomaterials are promising building blocks for wearable sensors. Recent advances in the nanomaterial-enabled wearable sensors including temperature, electrophysiological, strain, tactile, electrochemical, and environmental sensors are presented in this review. Integration of multiple sensors for multimodal sensing and integration with other components into wearable systems are summarized. Representative applications of nanomaterial-enabled wearable sensors for healthcare, including continuous health monitoring, daily and sports activity tracking, and multifunctional electronic skin are highlighted. Finally, challenges, opportunities, and future perspectives in the field of nanomaterial-enabled wearable sensors are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Techniques for physicochemical characterization of nanomaterials

PubMed Central

Lin, Ping-Chang; Lin, Stephen; Wang, Paul C.; Sridhar, Rajagopalan

2014-01-01

Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics. PMID:24252561

Nanomaterials for membrane fouling control: accomplishments and challenges.

PubMed

Yang, Qian; Mi, Baoxia

2013-11-01

We report a review of recent research efforts on incorporating nanomaterials-including metal/metal oxide nanoparticles, carbon-based nanomaterials, and polymeric nanomaterials-into/onto membranes to improve membrane antifouling properties in biomedical or potentially medical-related applications. In general, nanomaterials can be incorporated into/onto a membrane by blending them into membrane fabricating materials or by attaching them to membrane surfaces via physical or chemical approaches. Overall, the fascinating, multifaceted properties (eg, high hydrophilicity, superparamagnetic properties, antibacterial properties, amenable functionality, strong hydration capability) of nanomaterials provide numerous novel strategies and unprecedented opportunities to fully mitigate membrane fouling. However, there are still challenges in achieving a broader adoption of nanomaterials in the membrane processes used for biomedical applications. Most of these challenges arise from the concerns over their long-term antifouling performance, hemocompatibility, and toxicity toward humans. Therefore, rigorous investigation is still needed before the adoption of some of these nanomaterials in biomedical applications, especially for those nanomaterials proposed to be used in the human body or in contact with living tissue/body fluids for a long period of time. Nevertheless, it is reasonable to predict that the service lifetime of membrane-based biomedical devices and implants will be prolonged significantly with the adoption of appropriate fouling control strategies. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Solar Photoelectrochemical Energy Conversion using Earth-Abundant Nanomaterials

NASA Astrophysics Data System (ADS)

Lukowski, Mark A.

Although the vast majority of energy consumed worldwide is derived from fossil fuels, the growing interest in making cleaner alternative energies more economically viable has motivated recent research efforts aimed to improve photovoltaic, wind, and biomass power generation. Clean power generation also requires clean burning fuels, such as H2 and O2, so that energy can still be provided on demand at all times, despite the intermittent nature inherent to solar or wind power. My research has focused on the rational approach to synthesizing earth-abundant nanomaterials with applications in the generation of clean alternative fuels and understanding the structure-property relationships which directly influence their performance. Herein, we describe the development of low-cost, earth-abundant layered metal chalcogenides as high-performance electrocatalysts for hydrogen evolution, and hematite photoanodes for photoelectrochemical oxygen evolution. This work has revealed a particularly interesting concept where catalytic performance can be enhanced by controlling the phase behavior of the material and taking advantage of previously unexploited properties to overcome the challenges traditionally limiting the performance of these layered materials for hydrogen evolution catalysis.

Quantum dot-decorated semiconductor micro- and nanoparticles: A review of their synthesis, characterization and application in photocatalysis.

PubMed

Bajorowicz, Beata; Kobylański, Marek P; Gołąbiewska, Anna; Nadolna, Joanna; Zaleska-Medynska, Adriana; Malankowska, Anna

2018-06-01

Quantum dot (QD)-decorated semiconductor micro- and nanoparticles are a new class of functional nanomaterials that have attracted considerable interest for their unique structural, optical and electronic properties that result from the large surface-to-volume ratio and the quantum confinement effect. In addition, because of QDs' excellent light-harvesting capacity, unique photoinduced electron transfer, and up-conversion behaviour, semiconductor nanoparticles decorated with quantum dots have been used widely in photocatalytic applications for the degradation of organic pollutants in both the gas and aqueous phases. This review is a comprehensive overview of the recent progress in synthesis methods for quantum dots and quantum dot-decorated semiconductor composites with an emphasis on their composition, morphology and optical behaviour. Furthermore, various approaches used for the preparation of QD-based composites are discussed in detail with respect to visible and UV light-induced photoactivity. Finally, an outlook on future development is proposed with the goal of overcoming challenges and stimulating further research into this promising field. Copyright © 2018 Elsevier B.V. All rights reserved.

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. In this mini-review, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. The challenges and opportunitiesmore » in this new field are also discussed.« less

Reinforcement of cement-based matrices with graphite nanomaterials

NASA Astrophysics Data System (ADS)

Sadiq, Muhammad Maqbool

Cement-based materials offer a desirable balance of compressive strength, moisture resistance, durability, economy and energy-efficiency; their tensile strength, fracture energy and durability in aggressive environments, however, could benefit from further improvements. An option for realizing some of these improvements involves introduction of discrete fibers into concrete. When compared with today's micro-scale (steel, polypropylene, glass, etc.) fibers, graphite nanomaterials (carbon nanotube, nanofiber and graphite nanoplatelet) offer superior geometric, mechanical and physical characteristics. Graphite nanomaterials would realize their reinforcement potential as far as they are thoroughly dispersed within cement-based matrices, and effectively bond to cement hydrates. The research reported herein developed non-covalent and covalent surface modification techniques to improve the dispersion and interfacial interactions of graphite nanomaterials in cement-based matrices with a dense and well graded micro-structure. The most successful approach involved polymer wrapping of nanomaterials for increasing the density of hydrophilic groups on the nanomaterial surface without causing any damage to the their structure. The nanomaterials were characterized using various spectrometry techniques, and SEM (Scanning Electron Microscopy). The graphite nanomaterials were dispersed via selected sonication procedures in the mixing water of the cement-based matrix; conventional mixing and sample preparation techniques were then employed to prepare the cement-based nanocomposite samples, which were subjected to steam curing. Comprehensive engineering and durability characteristics of cement-based nanocomposites were determined and their chemical composition, microstructure and failure mechanisms were also assessed through various spectrometry, thermogravimetry, electron microscopy and elemental analyses. Both functionalized and non-functionalized nanomaterials as well as different

Experimentally evaluating the origin of dilute magnetism in nanomaterials

NASA Astrophysics Data System (ADS)

Pereira, L. M. C.

2017-10-01

Reports of room-temperature ferromagnetism continue to emerge for an ever-growing range of nanomaterials with a small or even vanishing concentration of magnetic atoms. Dilute magnetic semiconductors (DMS) are the most representative class of such materials, but similar magnetic properties have been reported in many others. Challenging our understanding of magnetic order in solids, as well as our ability to experimentally assess it, these remarkable magnetic phenomena have become one of the most controversial topics in magnetism. Various non-intrinsic sources of ferromagnetism (e.g. instrumental artifacts and magnetic contamination) are becoming well documented, and rarely are all of them taken into account when room-temperature ferromagnetism is reported. This topical review is intended to serve as a guide when evaluating to what extent a given data set supports the claim of intrinsic ferromagnetism in dilute nanomaterials. It compiles the most relevant sources of non-intrinsic ferromagnetism which have been reported, as well as guidelines for how to minimize them. It also provides an overview of complementary structural and magnetic characterization techniques which can be combined to provide different levels of scrutiny of the intrinsic nature of experimentally observed ferromagnetism. In particular, it gives some notable examples of how comprehensive studies based on those techniques have led to a remarkably detailed understanding of model DMS materials, with strong evidence of absence of room-temperature ferromagnetism. Although mostly based on DMS research, this review provides a set of guidelines and cautionary notes of broader relevance, including some emerging new fields of dilute nanomagnetism such as magnetically doped 3D topological insulators, 3D Dirac semimetals, and 2D materials.

Porous substrates filled with nanomaterials

DOEpatents

Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.; Stadermann, Michael

2018-04-03

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.

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.

Effects of Engineered Nanomaterials on Plants Growth: An Overview

PubMed Central

Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Juraimi, Abdul Shukor; Hashemi, Farahnaz Sadat Golestan

2014-01-01

Rapid development and wide applications of nanotechnology brought about a significant increment on the number of engineered nanomaterials (ENs) inevitably entering our living system. Plants comprise of a very important living component of the terrestrial ecosystem. Studies on the influence of engineered nanomaterials (carbon and metal/metal oxides based) on plant growth indicated that in the excess content, engineered nanomaterials influences seed germination. It assessed the shoot-to-root ratio and the growth of the seedlings. From the toxicological studies to date, certain types of engineered nanomaterials can be toxic once they are not bound to a substrate or if they are freely circulating in living systems. It is assumed that the different types of engineered nanomaterials affect the different routes, behavior, and the capability of the plants. Furthermore, different, or even opposing conclusions, have been drawn from most studies on the interactions between engineered nanomaterials with plants. Therefore, this paper comprehensively reviews the studies on the different types of engineered nanomaterials and their interactions with different plant species, including the phytotoxicity, uptakes, and translocation of engineered nanomaterials by the plant at the whole plant and cellular level. PMID:25202734

Biological interactions of carbon-based nanomaterials: From coronation to degradation.

PubMed

Bhattacharya, Kunal; Mukherjee, Sourav P; Gallud, Audrey; Burkert, Seth C; Bistarelli, Silvia; Bellucci, Stefano; Bottini, Massimo; Star, Alexander; Fadeel, Bengt

2016-02-01

Carbon-based nanomaterials including carbon nanotubes, graphene oxide, fullerenes and nanodiamonds are potential candidates for various applications in medicine such as drug delivery and imaging. However, the successful translation of nanomaterials for biomedical applications is predicated on a detailed understanding of the biological interactions of these materials. Indeed, the potential impact of the so-called bio-corona of proteins, lipids, and other biomolecules on the fate of nanomaterials in the body should not be ignored. Enzymatic degradation of carbon-based nanomaterials by immune-competent cells serves as a special case of bio-corona interactions with important implications for the medical use of such nanomaterials. In the present review, we highlight emerging biomedical applications of carbon-based nanomaterials. We also discuss recent studies on nanomaterial 'coronation' and how this impacts on biodistribution and targeting along with studies on the enzymatic degradation of carbon-based nanomaterials, and the role of surface modification of nanomaterials for these biological interactions. Advances in technology have produced many carbon-based nanomaterials. These are increasingly being investigated for the use in diagnostics and therapeutics. Nonetheless, there remains a knowledge gap in terms of the understanding of the biological interactions of these materials. In this paper, the authors provided a comprehensive review on the recent biomedical applications and the interactions of various carbon-based nanomaterials. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Grouping nanomaterials to predict their potential to induce pulmonary inflammation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braakhuis, Hedwig M., E-mail: hedwig.braakhuis@rivm.nl; Department of Toxicogenomics, Maastricht University, PO Box 616, 6200 MD Maastricht; Oomen, Agnes G.

The rapidly expanding manufacturing, production and use of nanomaterials have raised concerns for both worker and consumer safety. Various studies have been published in which induction of pulmonary inflammation after inhalation exposure to nanomaterials has been described. Nanomaterials can vary in aspects such as size, shape, charge, crystallinity, chemical composition, and dissolution rate. Currently, efforts are made to increase the knowledge on the characteristics of nanomaterials that can be used to categorise them into hazard groups according to these characteristics. Grouping helps to gather information on nanomaterials in an efficient way with the aim to aid risk assessment. Here, wemore » discuss different ways of grouping nanomaterials for their risk assessment after inhalation. Since the relation between single intrinsic particle characteristics and the severity of pulmonary inflammation is unknown, grouping of nanomaterials by their intrinsic characteristics alone is not sufficient to predict their risk after inhalation. The biokinetics of nanomaterials should be taken into account as that affects the dose present at a target site over time. The parameters determining the kinetic behaviour are not the same as the hazard-determining parameters. Furthermore, characteristics of nanomaterials change in the life-cycle, resulting in human exposure to different forms and doses of these nanomaterials. As information on the biokinetics and in situ characteristics of nanomaterials is essential but often lacking, efforts should be made to include these in testing strategies. Grouping nanomaterials will probably be of the most value to risk assessors when information on intrinsic characteristics, life-cycle, biokinetics and effects are all combined. - Highlights: • Grouping of nanomaterials helps to gather information in an efficient way with the aim to aid risk assessment. • Different ways of grouping nanomaterials for their risk assessment after inhalation

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of plant-mediated gold nanoparticles and catalytic role of biomatrix-embedded nanomaterials

PubMed Central

Sharma, Nilesh C.; Nath, Sudip; Parsons, Jason G.; Gardea- Torresdey, Jorge L.; Pal, Tarasankar

2008-01-01

Growth of Sesbania seedlings in chloroaurate solution resulted in the accumulation of gold with the formation of stable gold nanoparticles in plant tissues. Transmission electron microscopy revealed the intracellular distribution of monodisperse nanospheres, possibly due to reduction of the metal ions by secondary metabolites present in cells. X-ray absorption near-edge structure and extended X-ray absorption fine structure demonstrated a high degree of efficiency for the biotransformation of Au(III) into Au(0) by plant tissues. The catalytic function of the nanoparticle-rich biomass was substantiated by the reduction of aqueous 4-nitrophenol (4-NP). This is the first report of gold nanoparticle-bearing biomatrix directly reducing a toxic pollutant, 4-NP. PMID:17711235

Describing Nanomaterials: A Uniform Description System

NASA Astrophysics Data System (ADS)

Rumble, John; Freiman, Steve; Teague, Clayton

2014-03-01

Products involving nanomaterials are growing rapidly and nanoparticles also occur naturally. Materials, scientists, engineers, health officials, and regulators have realized they need a common description system. Led by CODATA and VAMAS, a Uniform Description System (UDS) for nanomaterials is being developed to meet the requirements of a broad range of scientific and technical disciplines and different user communities. The goal of the CODATA/VAMAS effort is the creation of a complete set of descriptors that can be used by all communities, e.g., materials, physics, chemistry, agricultural, medical, etc., interested in nanomaterials. The description system must be relevant to researchers, manufacturers of nanomaterials, materials selectors, and regulators. The purpose of the UDS for materials on the nanoscale is twofold: Uniqueness and Equivalency. The first step in the development of the UDS has been the creation of a Framework that will be used by the different communities to guide in the selection of descriptors relevant to their needs. This talk is a brief description of the draft of such a Framework, and how the framework will be translated into a robust description system with input from many scientific communities including physics. A contribution from the CODATA/VAMAS Working Group on the Description of Nanomaterials.

Size effects of latex nanomaterials on lung inflammation in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inoue, Ken-ichiro; Takano, Hirohisa; Yanagisawa, Rie

Effects of nano-sized materials (nanomaterials) on sensitive population have not been well elucidated. This study examined the effects of pulmonary exposure to (latex) nanomaterials on lung inflammation related to lipopolysaccharide (LPS) or allergen in mice, especially in terms of their size-dependency. In protocol 1, ICR male mice were divided into 8 experimental groups that intratracheally received a single exposure to vehicle, latex nanomaterials (250 {mu}g/animal) with three sizes (25, 50, and 100 nm), LPS (75 {mu}g/animal), or LPS plus latex nanomaterials. In protocol 2, ICR male mice were divided into 8 experimental groups that intratracheally received repeated exposure to vehicle,more » latex nanomaterials (100 {mu}g/animal), allergen (ovalbumin: OVA; 1 {mu}g/animal), or allergen plus latex nanomaterials. In protocol 1, latex nanomaterials with all sizes exacerbated lung inflammation elicited by LPS, showing an overall trend of amplified lung expressions of proinflammatory cytokines. Furthermore, LPS plus nanomaterials, especially with size less than 50 nm, significantly elevated circulatory levels of fibrinogen, macrophage chemoattractant protein-1, and keratinocyte-derived chemoattractant, and von Willebrand factor as compared with LPS alone. The enhancement tended overall to be greater with the smaller nanomaterials than with the larger ones. In protocol 2, latex nanomaterials with all sizes did not significantly enhance the pathophysiology of allergic asthma, characterized by eosinophilic lung inflammation and Igs production, although latex nanomaterials with less than 50 nm significantly induced/enhanced neutrophilic lung inflammation. These results suggest that latex nanomaterials differentially affect two types of (innate and adaptive immunity-dominant) lung inflammation.« less

Grouping nanomaterials to predict their potential to induce pulmonary inflammation.

PubMed

Braakhuis, Hedwig M; Oomen, Agnes G; Cassee, Flemming R

2016-05-15

The rapidly expanding manufacturing, production and use of nanomaterials have raised concerns for both worker and consumer safety. Various studies have been published in which induction of pulmonary inflammation after inhalation exposure to nanomaterials has been described. Nanomaterials can vary in aspects such as size, shape, charge, crystallinity, chemical composition, and dissolution rate. Currently, efforts are made to increase the knowledge on the characteristics of nanomaterials that can be used to categorise them into hazard groups according to these characteristics. Grouping helps to gather information on nanomaterials in an efficient way with the aim to aid risk assessment. Here, we discuss different ways of grouping nanomaterials for their risk assessment after inhalation. Since the relation between single intrinsic particle characteristics and the severity of pulmonary inflammation is unknown, grouping of nanomaterials by their intrinsic characteristics alone is not sufficient to predict their risk after inhalation. The biokinetics of nanomaterials should be taken into account as that affects the dose present at a target site over time. The parameters determining the kinetic behaviour are not the same as the hazard-determining parameters. Furthermore, characteristics of nanomaterials change in the life-cycle, resulting in human exposure to different forms and doses of these nanomaterials. As information on the biokinetics and in situ characteristics of nanomaterials is essential but often lacking, efforts should be made to include these in testing strategies. Grouping nanomaterials will probably be of the most value to risk assessors when information on intrinsic characteristics, life-cycle, biokinetics and effects are all combined. Copyright © 2015 Elsevier Inc. All rights reserved.

Platinum Nanoparticle Loading of Boron Nitride Aerogel and Its Use as a Novel Material for Low-Power Catalytic Gas Sensing

DOE PAGES

Harley-Trochimczyk, Anna; Pham, Thang; Chang, Jiyoung; ...

2015-12-09

We report that a high-surface-area, highly crystalline boron nitride aerogel synthesized with nonhazardous reactants has been loaded with crystalline platinum nanoparticles to form a novel nanomaterial that exhibits many advantages for use in a catalytic gas sensing application. The platinum nanoparticle-loaded boron nitride aerogel integrated onto a microheater platform allows for calorimetric propane detection. The boron nitride aerogel exhibits thermal stability up to 900 °C and supports disperse platinum nanoparticles, with no sintering observed after 24 h of high-temperature testing. The high thermal conductivity and low density of the boron nitride aerogel result in an order of magnitude faster responsemore » and recovery times (<2 s) than reported on alumina support and allow for 10% duty cycling of the microheater with no loss in sensitivity. Lastly, the resulting 1.5 mW sensor power consumption is two orders of magnitude less than commercially available catalytic gas sensors and unlocks the potential for wireless, battery-powered catalytic gas sensing.« less

Preparation of Pt Ag alloy nanoisland/graphene hybrid composites and its high stability and catalytic activity in methanol electro-oxidation

PubMed Central

2011-01-01

In this article, PtAg alloy nanoislands/graphene hybrid composites were prepared based on the self-organization of Au@PtAg nanorods on graphene sheets. Graphite oxides (GO) were prepared and separated to individual sheets using Hummer's method. Graphene nano-sheets were prepared by chemical reduction with hydrazine. The prepared PtAg alloy nanomaterial and the hybrid composites with graphene were characterized by SEM, TEM, and zeta potential measurements. It is confirmed that the prepared Au@PtAg alloy nanorods/graphene hybrid composites own good catalytic function for methanol electro-oxidation by cyclic voltammograms measurements, and exhibited higher catalytic activity and more stability than pure Au@Pt nanorods and Au@AgPt alloy nanorods. In conclusion, the prepared PtAg alloy nanoislands/graphene hybrid composites own high stability and catalytic activity in methanol electro-oxidation, so that it is one kind of high-performance catalyst, and has great potential in applications such as methanol fuel cells in near future. PMID:21982417

Investigating the Synthesis, Structure, and Catalytic Properties of Versatile Gold-Based Nanocatalvsts

NASA Astrophysics Data System (ADS)

Pretzer, Lori A.

Transition metal nanomaterials are used to catalyze many chemical reactions, including those key to environmental, medicinal, and petrochemical fields. Improving their catalytic properties and lifetime would have significant economic and environmental rewards. Potentially expedient options to make such advancements are to alter the shape, size, or composition of transition metal nanocatalysts. This work investigates the relationships between structure and catalytic properties of synthesized Au, Pd-on-Au, and Au-enzyme model transition metal nanocatalysts. Au and Pd-on-Au nanomaterials were studied due to their wide-spread application and structure-dependent electronic and geometric properties. The goal of this thesis is to contribute design procedures and synthesis methods that enable the preparation of more efficient transition metal nanocatalysts. The influence of the size and composition of Pd-on-Au nanoparticles (NPs) was systematically investigated and each was found to affect the catalyst's surface structure and catalytic properties. The catalytic hydrodechlorination of trichloroethene and reduction of 4-nitrophenol by Pd-on-Au nanoparticles were investigated as these reactions are useful for environmental and pharmaceutical synthesis applications, respectively. Structural characterization revealed that the dispersion and oxidation state of surface Pd atoms are controlled by the Au particle size and concentration of Pd. These structural changes are correlated with observed Pd-on-Au NP activities for both probe reactions, providing new insight into the structure-activity relationships of bimetallic nanocatalysts. Using the structure-dependent electronic properties of Au NPs, a new type of light-triggered biocatalyst was prepared and used to remotely control a model biochemical reaction. This biocatalyst consists of a model thermophilic glucokinase enzyme covalently attached to the surface of Au nanorods. The rod-like shape of the Au nanoparticles made the

A Hybrid Co Quaterpyridine Complex/Carbon Nanotube Catalytic Material for CO2 Reduction in Water.

PubMed

Wang, Min; Chen, Lingjing; Lau, Tai-Chu; Robert, Marc

2018-06-25

Associating a metal-based catalyst to a carbon-based nanomaterial is a promising approach for the production of solar fuels from CO 2 . Upon appending a Co II quaterpyridine complex [Co(qpy)] 2+ at the surface of multi-walled carbon nanotubes, CO 2 conversion into CO was realized in water at pH 7.3 with 100 % catalytic selectivity and 100 % Faradaic efficiency, at low catalyst loading and reduced overpotential. A current density of 0.94 mA cm -2 was reached at -0.35 V vs. RHE (240 mV overpotential), and 9.3 mA cm -2 could be sustained for hours at only 340 mV overpotential with excellent catalyst stability (89 095 catalytic cycles in 4.5 h), while 19.9 mA cm -2 was met at 440 mV overpotential. Such a hybrid material combines the high selectivity of a homogeneous molecular catalyst to the robustness of a heterogeneous material. Catalytic performances compare well with those of noble-metal-based nano-electrocatalysts and atomically dispersed metal atoms in carbon matrices. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Safety Aspects of Bio-Based Nanomaterials.

PubMed

Catalán, Julia; Norppa, Hannu

2017-12-01

Moving towards a bio-based and circular economy implies a major focus on the responsible and sustainable utilization of bio-resources. The emergence of nanotechnology has opened multiple possibilities, not only in the existing industrial sectors, but also for completely novel applications of nanoscale bio-materials, the commercial exploitation of which has only begun during the last few years. Bio-based materials are often assumed not to be toxic. However, this pre-assumption is not necessarily true. Here, we provide a short overview on health and environmental aspects associated with bio-based nanomaterials, and on the relevant regulatory requirements. We also discuss testing strategies that may be used for screening purposes at pre-commercial stages. Although the tests presently used to reveal hazards are still evolving, regarding modifi-cations required for nanomaterials, their application is needed before the upscaling or commercialization of bio-based nanomaterials, to ensure the market potential of the nanomaterials is not delayed by uncertainties about safety issues.

Engineered Nanomaterials: Their Physicochemical Characteristics and How to Measure Them.

PubMed

Atluri, Rambabu; Jensen, Keld Alstrup

2017-01-01

Numerous types of engineered nanomaterials (ENMs) are commercially available and developments move towards producing more advanced nanomaterials with tailored properties. Such advanced nanomaterials may include chemically doped or modified derivatives with specific surface chemistries; also called higher generation or multiconstituent nanomaterials. To fully enjoy the benefits of nanomaterials, appropriate characterisation of ENMs is necessary for many aspects of their production, use, testing and reporting to regulatory bodies. This chapter introduces both structural and textural properties of nanomaterials with a focus on demonstrating the information that can be achieved by analysis of primary physicochemical characteristics and how such information is critical to understand or assess the possible toxicity of engineered nanomaterials. Many of characterization methods are very specific to obtain particular characteristics and therefore the most widely used techniques are explained and demonstrated.

Classifying Nanomaterial Risks Using Multi-Criteria Decision Analysis

NASA Astrophysics Data System (ADS)

Linkov, I.; Steevens, J.; Chappell, M.; Tervonen, T.; Figueira, J. R.; Merad, M.

There is rapidly growing interest by regulatory agencies and stakeholders in the potential toxicity and other risks associated with nanomaterials throughout the different stages of the product life cycle (e.g., development, production, use and disposal). Risk assessment methods and tools developed and applied to chemical and biological material may not be readily adaptable for nanomaterials because of the current uncertainty in identifying the relevant physico-chemical and biological properties that adequately describe the materials. Such uncertainty is further driven by the substantial variations in the properties of the original material because of the variable manufacturing processes employed in nanomaterial production. To guide scientists and engineers in nanomaterial research and application as well as promote the safe use/handling of these materials, we propose a decision support system for classifying nanomaterials into different risk categories. The classification system is based on a set of performance metrics that measure both the toxicity and physico-chemical characteristics of the original materials, as well as the expected environmental impacts through the product life cycle. The stochastic multicriteria acceptability analysis (SMAA-TRI), a formal decision analysis method, was used as the foundation for this task. This method allowed us to cluster various nanomaterials in different risk categories based on our current knowledge of nanomaterial's physico-chemical characteristics, variation in produced material, and best professional judgement. SMAA-TRI uses Monte Carlo simulations to explore all feasible values for weights, criteria measurements, and other model parameters to assess the robustness of nanomaterial grouping for risk management purposes.1,2

Predictive modeling of nanomaterial exposure effects in biological systems

PubMed Central

Liu, Xiong; Tang, Kaizhi; Harper, Stacey; Harper, Bryan; Steevens, Jeffery A; Xu, Roger

2013-01-01

Background Predictive modeling of the biological effects of nanomaterials is critical for industry and policymakers to assess the potential hazards resulting from the application of engineered nanomaterials. Methods We generated an experimental dataset on the toxic effects experienced by embryonic zebrafish due to exposure to nanomaterials. Several nanomaterials were studied, such as metal nanoparticles, dendrimer, metal oxide, and polymeric materials. The embryonic zebrafish metric (EZ Metric) was used as a screening-level measurement representative of adverse effects. Using the dataset, we developed a data mining approach to model the toxic endpoints and the overall biological impact of nanomaterials. Data mining techniques, such as numerical prediction, can assist analysts in developing risk assessment models for nanomaterials. Results We found several important attributes that contribute to the 24 hours post-fertilization (hpf) mortality, such as dosage concentration, shell composition, and surface charge. These findings concur with previous studies on nanomaterial toxicity using embryonic zebrafish. We conducted case studies on modeling the overall effect/impact of nanomaterials and the specific toxic endpoints such as mortality, delayed development, and morphological malformations. The results show that we can achieve high prediction accuracy for certain biological effects, such as 24 hpf mortality, 120 hpf mortality, and 120 hpf heart malformation. The results also show that the weighting scheme for individual biological effects has a significant influence on modeling the overall impact of nanomaterials. Sample prediction models can be found at http://neiminer.i-a-i.com/nei_models. Conclusion The EZ Metric-based data mining approach has been shown to have predictive power. The results provide valuable insights into the modeling and understanding of nanomaterial exposure effects. PMID:24098077

An Investigation of Carbon-Based Nanomaterials for Efficient Energy Production And Delivery

NASA Astrophysics Data System (ADS)

Gangoli, Varun Shenoy

Carbon-based nanomaterials have been demonstrated to have different potential applications in the energy industry. However, there are challenges in the realization of these applications. Chirality of single wall carbon nanotubes (SWCNTs) defines their electronic properties, and obtaining an ensemble of SWCNTs of the same chirality has been a problem studied for over two decades with no clear solution yet. Other carbon-based nanomaterials, such as carbon black aggregates, are hydrophobic in nature and potential applications in the oil and gas industry require their dispersal in an aqueous solvent. Another application in the oil and gas industry is enhanced oil recovery (EOR), and here there is a need for an inexpensive, stable, and efficient surfactant compared to currently used industrial solutions. The challenge of producing SWCNTs of the same chirality is studied using two approaches--separation after synthesis of SWCNTs of mixed chiralities, and chemical control over chirality of as-synthesized SWCNTs. Agarose gel-based affinity chromatography was used as a means towards highly semiconductor- enriched SWCNTs using a family of nonionic surfactants. UV-vis-NIR spectroscopy, Raman spectroscopy and photoluminescence spectroscopy was used to quantify the separation efficiency of the metal- and semiconductor-enriched SWCNTs. This process is an improvement over other chromatography-based techniques at the time in that the nonionic surfactants used are less expensive, enable a higher purity of semiconductor SWCNTs (>95%) and decompose fully by simply heating in air thus leaving behind pristine SWCNTs. The second approach was based on using catalyst dopants to preferentially synthesize SWCNTs of a particular chirality at the expense of SWCNTs of other chiralities. Heterogeneous catalysis combined with the screw dislocation theory of SWCNT growth provided the background for this work, and both selenium and phosphorus were identified as chemical dopants for iron catalysts

Nanomaterials and Retinal Toxicity | Science Inventory | US ...

EPA Pesticide Factsheets

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 and then crossing the blood-retinal barrier; and through the choroidal blood supply, crossing the Bruch's membrane and the retinal pigment epithelium (RPE). The blood-retinal barrier is functionally similar to the blood-brain barrier, normally restricting transport of larger sized materials, but particles in the lower nanomaterial size range can be expected to transit. The blood flow to the retinal choroid is, on a tissue mass basis, one of the highest in the body raising the potential for rapid delivery of nanomaterials to the RPE. In vitro, RPE cells rapidly uptake nano particles, transport and agglomerate them in the perinuclear cytoplasm. In vivo studies have shown that the eye can uptake nanomaterials and retain them longer than many other tissues after cessation of exposure. Toxicity from nanomaterials to the neural retina or the RPE would be expected to follow common mechanisms identified for other tissues including generation of reactive oxygen species, alteration of cellular redox status, altered intracellular signaling, and release of toxic metal ions from soluble metallic particles. The retina and other ocular tissues, however, have potential for additional phototoxic mechanism

Electrochemical nonenzymatic sensing of glucose using advanced nanomaterials.

PubMed

Dhara, Keerthy; Mahapatra, Debiprosad Roy

2017-12-13

An overview (with 376 refs.) is given here on the current state of methods for electrochemical sensing of glucose based on the use of advanced nanomaterials. An introduction into the field covers aspects of enzyme based sensing versus nonenzymatic sensing using nanomaterials. The next chapter cover the most commonly used nanomaterials for use in such sensors, with sections on uses of noble metals, transition metals, metal oxides, metal hydroxides, and metal sulfides, on bimetallic nanoparticles and alloys, and on other composites. A further section treats electrodes based on the use of carbon nanomaterials (with subsections on carbon nanotubes, on graphene, graphene oxide and carbon dots, and on other carbonaceous nanomaterials. The mechanisms for electro-catalysis are also discussed, and several Tables are given where the performance of sensors is being compared. Finally, the review addresses merits and limitations (such as the frequent need for working in strongly etching alkaline solutions and the need for diluting samples because sensors often have analytical ranges that are far below the glucose levels found in blood). We also address market/technology gaps in comparison to commercially available enzymatic sensors. Graphical Abstract Schematic representation of electrochemical nonenzymatic glucose sensing on the nanomaterials modified electrodes. At an applied potential, the nanomaterial-modified electrodes exhibit excellent electrocatalytic activity for direct oxidation of glucose oxidation.

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...

Risk assessment strategies as nanomaterials transition into commercial applications

NASA Astrophysics Data System (ADS)

Olson, Mira S.; Gurian, Patrick L.

2012-03-01

Commercial applications of nanomaterials are rapidly emerging in the marketplace. The environmental and human health risks of many nanomaterials remain unknown, and prioritizing how to efficiently assess their risks is essential. As nanomaterials are incorporated into a broader range of commercial products, their potential for environmental release and human exposure not only increases, but also becomes more difficult to model accurately. Emphasis may first be placed on estimating potential environmental exposure based on pertinent physical properties of the nanomaterials. Given that the greatest potential for global environmental impacts results from nanomaterials that are both persistent and toxic, this paper advocates screening first for persistence since it is easier to assess than toxicity. For materials that show potential for persistence, a higher burden of proof of their non-toxicity is suggested before they enter the commercial marketplace whereas a lower burden of proof may be acceptable for nanomaterials that are less persistent.

The potential of protein-nanomaterial interaction for advanced drug delivery.

PubMed

Peng, Qiang; Mu, Huiling

2016-03-10

Nanomaterials, like nanoparticles, micelles, nano-sheets, nanotubes and quantum dots, have great potentials in biomedical fields. However, their delivery is highly limited by the formation of protein corona upon interaction with endogenous proteins. This new identity, instead of nanomaterial itself, would be the real substance the organs and cells firstly encounter. Consequently, the behavior of nanomaterials in vivo is uncontrollable and some undesired effects may occur, like rapid clearance from blood stream; risk of capillary blockage; loss of targeting capacity; and potential toxicity. Therefore, protein-nanomaterial interaction is a great challenge for nanomaterial systems and should be inhibited. However, this interaction can also be used to functionalize nanomaterials by forming a selected protein corona. Unlike other decoration using exogenous molecules, nanomaterials functionalized by selected protein corona using endogenous proteins would have greater promise for clinical use. In this review, we aim to provide a comprehensive understanding of protein-nanomaterial interaction. Importantly, a discussion about how to use such interaction is launched and some possible applications of such interaction for advanced drug delivery are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

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

Exploring the possibilities and limitations of a nanomaterials genome.

PubMed

Qian, Chenxi; Siler, Todd; Ozin, Geoffrey A

2015-01-07

What are we going to do with the cornucopia of nanomaterials appearing in the open and patent literature, every day? Imagine the benefits of an intelligent and convenient means of categorizing, organizing, sifting, sorting, connecting, and utilizing this information in scientifically and technologically innovative ways by building a Nanomaterials Genome founded upon an all-purpose Periodic Table of Nanomaterials. In this Concept article, inspired by work on the Human Genome project, which began in 1989 together with motivation from the recent emergence of the Materials Genome project initiated in 2011 and the Nanoinformatics Roadmap 2020 instigated in 2010, we envision the development of a Nanomaterials Genome (NMG) database with the most advanced data-mining tools that leverage inference engines to help connect and interpret patterns of nanomaterials information. It will be equipped with state-of-the-art visualization techniques that rapidly organize and picture, categorize and interrelate the inherited behavior of complex nanomatter from the information programmed in its constituent nanomaterials building blocks. A Nanomaterials Genome Initiative (NMGI) of the type imagined herein has the potential to serve the global nanoscience community with an opportunity to speed up the development continuum of nanomaterials through the innovation process steps of discovery, structure determination and property optimization, functionality elucidation, system design and integration, certification and manufacturing to deployment in technologies that apply these versatile nanomaterials in environmentally responsible ways. The possibilities and limitations of this concept are critically evaluated in this article. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy Device Applications of Synthesized 1D Polymer Nanomaterials.

PubMed

Huang, Long-Biao; Xu, Wei; Hao, Jianhua

2017-11-01

1D polymer nanomaterials as emerging materials, such as nanowires, nanotubes, and nanopillars, have attracted extensive attention in academia and industry. The distinctive, various, and tunable structures in the nanoscale of 1D polymer nanomaterials present nanointerfaces, high surface-to-volume ratio, and large surface area, which can improve the performance of energy devices. In this review, representative fabrication techniques of 1D polymer nanomaterials are summarized, including electrospinning, template-assisted, template-free, and inductively coupled plasma methods. The recent advancements of 1D polymer nanomaterials in energy device applications are demonstrated. Lastly, existing challenges and prospects of 1D polymer nanomaterials for energy device applications are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Allergic Responses Induced by the Immunomodulatory Effects of Nanomaterials upon Skin Exposure

PubMed Central

Yoshioka, Yasuo; Kuroda, Etsushi; Hirai, Toshiro; Tsutsumi, Yasuo; Ishii, Ken J.

2017-01-01

Over the past decade, a vast array of nanomaterials has been created through the development of nanotechnology. With the increasing application of these nanomaterials in various fields, such as foods, cosmetics, and medicines, there has been concern about their safety, that is, nanotoxicity. Therefore, there is an urgent need to collect information about the biological effects of nanomaterials so that we can exploit their potential benefits and design safer nanomaterials, while avoiding nanotoxicity as a result of inhalation or skin exposure. In particular, the immunomodulating effect of nanomaterials is one of most interesting aspects of nanotoxicity. However, the immunomodulating effects of nanomaterials through skin exposure have not been adequately discussed compared with the effects of inhalation exposure, because skin penetration by nanomaterials is thought to be extremely low under normal conditions. On the other hand, the immunomodulatory effects of nanomaterials via skin may cause severe problems for people with impaired skin barrier function, because some nanomaterials could penetrate the deep layers of their allergic or damaged skin. In addition, some studies, including ours, have shown that nanomaterials could exhibit significant immunomodulating effects even if they do not penetrate the skin. In this review, we summarize our current knowledge of the allergic responses induced by nanomaterials upon skin exposure. First, we discuss nanomaterial penetration of the intact or impaired skin barrier. Next, we describe the immunomodulating effects of nanomaterials, focusing on the sensitization potential of nanomaterials and the effects of co-exposure of nanomaterials with substances such as chemical sensitizers or allergens, on the onset of allergy, following skin exposure. Finally, we discuss the potential mechanisms underlying the immunomodulating effects of nanomaterials by describing the involvement of the protein corona in the interaction of

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.

Accelerating the Translation of Nanomaterials in Biomedicine

PubMed Central

Mitragotri, Samir; Anderson, Daniel G.; Chen, Xiaoyuan; Chow, Edward K.; Ho, Dean; Kabanov, Alexander V.; Karp, Jeffrey M.; Kataoka, Kazunori; Mirkin, Chad A.; Petrosko, Sarah Hurst; Shi, Jinjun; Stevens, Molly M.; Sun, Shouheng; Teoh, Sweehin; Venkatraman, Subbu S.; Xia, Younan; Wang, Shutao; Gu, Zhen; Xu, Chenjie

2017-01-01

Due to their size and tailorable physicochemical properties, nanomaterials are an emerging class of structures utilized in biomedical applications. There are now many prominent examples of nanomaterials being used to improve human health, in areas ranging from imaging and diagnostics to therapeutics and regenerative medicine. An overview of these examples reveals several common areas of synergy and future challenges. This Nano Focus discusses the current status and future potential of promising nanomaterials and their translation from the laboratory to the clinic, by highlighting a handful of successful examples. PMID:26115196

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...

Nanomaterials and nanofabrication for biomedical applications

NASA Astrophysics Data System (ADS)

Cheng, Chao-Min; Chia-Wen Wu, Kevin

2013-08-01

Traditional boundaries between materials science and engineering and life sciences are rapidly disintegrating as interdisciplinary research teams develop new materials-science-based tools for exploring fundamental issues in both medicine and biology. With recent technological advances in multiple research fields such as materials science, cell and molecular biology and micro-/nano-technology, much attention is shifting toward evaluating the functional advantages of nanomaterials and nanofabrication, at the cellular and molecular levels, for specific, biomedically relevant applications. The pursuit of this direction enhances the understanding of the mechanisms of, and therapeutic potentials for, some of the most lethal diseases, including cardiovascular diseases, organ fibrosis and cancers. This interdisciplinary approach has generated great interest among researchers working in a wide variety of communities including industry, universities and research laboratories. The purpose of this focus issue in Science and Technology of Advanced Materials is to bridge nanotechnology and biology with medicine, focusing more on the applications of nanomaterials and nanofabrication in biomedically relevant issues. This focus issue, we believe, will provide a more comprehensive understanding of (i) the preparation of nanomaterials and the underlying mechanisms of nanofabrication, and (ii) the linkage of nanomaterials and nanofabrication with biomedical applications. The multidisciplinary focus issue that we have attempted to organize is of interest to various research fields including biomaterials and tissue engineering, bioengineering, nanotechnology and nanomaterials, i.e. chemistry, physics and engineering. Nanomaterials and nanofabrication topics addressed in this focus issue include sensing and diagnosis (e.g. immunosensing and diagnostic devices for diseases), cellular and molecular biology (e.g. probing cellular behaviors and stem cell differentiation) and drug delivery

Recent development of nano-materials used in DNA biosensors.

PubMed

Xu, Kai; Huang, Junran; Ye, Zunzhong; Ying, Yibin; Li, Yanbin

2009-01-01

As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future.

Recent Development of Nano-Materials Used in DNA Biosensors

PubMed Central

Xu, Kai; Huang, Junran; Ye, Zunzhong; Ying, Yibin; Li, Yanbin

2009-01-01

As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future. PMID:22346713

Synthesis and applications of heterostructured semiconductor nanocrystals

NASA Astrophysics Data System (ADS)

Khon, Elena

light emmision tunability. We reported a general strategy for the assembly of all-inorganic light-emitting nanocrystal films with an emission quantum yield in the 30-52% range. Our methodology relies on solution-processing of CdSe nanocrystals into a crystalline matrix of a wide band gap semiconductor (CdS, ZnS). As a result, we replace original organic ligands on nanocrystal surfaces with an inorganic medium which efficiently preserves the quantum confinement of electrical charges in CdSe NCs. In addition to strong emission, fabricated films demonstrated excellent thermal and chemical stability, and a large refractive index, which avails their integration into emerging solid-state nanocrystal devices. The ability to control size and shape of NCs is essential as it automatically affects the optoelectronic properties of the crystals. Colloidal chemistry offers an assortment of synthetic tools for tuning the shape of NCs, but some nanoparticle morphologies require alternative processing strategies. We have shown that chemical etching of colloidal nanoparticles can facilitate the realization of desirable nanocrystal geometries. This methodology allows both CdSe and CdS composed semiconductor domains be exposed to the external environment, while maintaining a structural design that is highly desirable for catalytic applications. Hydrogen production tests confirmed the improved catalytic activity of CdSe/CdS dimers. We expect that the demonstrated application will become a common methodology in the synthesis of charge-separating nanocrystals, leading to advanced nanoparticle architectures for applications in the areas of photocatalysis, photovoltaics, and light detection.

Physicochemical and Electrophysical Properties of Metal/Semiconductor Containing Nanostructured Composites

NASA Astrophysics Data System (ADS)

Gerasimov, G. N.; Gromov, V. F.; Trakhtenberg, L. I.

2018-06-01

The properties of nanostructured composites based on metal oxides and metal-polymer materials are analyzed, along with ways of preparing them. The effect the interaction between metal and semiconductor nanoparticles has on the conductivity, photoconductivity, catalytic activity, and magnetic, dielectric, and sensor properties of nanocomposites is discussed. It is shown that as a result of this interaction, a material can acquire properties that do not exist in systems of isolated particles. The transfer of electrons between metal particles of different sizes in polymeric matrices leads to specific dielectric losses, and to an increase in the rate and a change in the direction of chemical reactions catalyzed by these particles. The interaction between metal-oxide semiconductor particles results in the electronic and chemical sensitization of sensor effects in nanostructured composite materials. Studies on creating molecular machines (Brownian motors), devices for magnetic recording of information, and high-temperature superconductors based on nanostructured systems are reviewed.

Biological responses to engineered nanomaterials: Needs for the next decade

DOE PAGES

Murphy, Catherine J.; Vartanian, Ariane M.; Geiger, Franz M.; ...

2015-06-09

In this study, the interaction of nanomaterials with biomolecules, cells, and organisms is an enormously vital area of current research, with applications in nanoenabled diagnostics, imaging agents, therapeutics, and contaminant removal technologies. Yet the potential for adverse biological and environmental impacts of nanomaterial exposure is considerable and needs to be addressed to ensure sustainable development of nanomaterials. In this Outlook four research needs for the next decade are outlined: (i) measurement of the chemical nature of nanomaterials in dynamic, complex aqueous environments; (ii) real-time measurements of nanomaterial-biological interactions with chemical specificity; (iii) delineation of molecular modes of action for nanomaterialmore » effects on living systems as functions of nanomaterial properties; and (iv) an integrated systems approach that includes computation and simulation across orders of magnitude in time and space.« less

Carbon Nanomaterials Interfacing with Neurons: An In vivo Perspective

PubMed Central

Baldrighi, Michele; Trusel, Massimo; Tonini, Raffaella; Giordani, Silvia

2016-01-01

Developing new tools that outperform current state of the art technologies for imaging, drug delivery or electrical sensing in neuronal tissues is one of the great challenges in neurosciences. Investigations into the potential use of carbon nanomaterials for such applications started about two decades ago. Since then, numerous in vitro studies have examined interactions between these nanomaterials and neurons, either by evaluating their compatibility, as vectors for drug delivery, or for their potential use in electric activity sensing and manipulation. The results obtained indicate that carbon nanomaterials may be suitable for medical therapies. However, a relatively small number of in vivo studies have been carried out to date. In order to facilitate the transformation of carbon nanomaterial into practical neurobiomedical applications, it is essential to identify and highlight in the existing literature the strengths and weakness that different carbon nanomaterials have displayed when probed in vivo. Unfortunately the current literature is sometimes sparse and confusing. To offer a clearer picture of the in vivo studies on carbon nanomaterials in the central nervous system, we provide a systematic and critical review. Hereby we identify properties and behavior of carbon nanomaterials in vivo inside the neural tissues, and we examine key achievements and potentially problematic toxicological issues. PMID:27375413

Occupational exposure limits for nanomaterials: state of the art

NASA Astrophysics Data System (ADS)

Schulte, P. A.; Murashov, V.; Zumwalde, R.; Kuempel, E. D.; Geraci, C. L.

2010-08-01

Assessing the need for and effectiveness of controlling airborne exposures to engineered nanomaterials in the workplace is difficult in the absence of occupational exposure limits (OELs). At present, there are practically no OELs specific to nanomaterials that have been adopted or promulgated by authoritative standards and guidance organizations. The vast heterogeneity of nanomaterials limits the number of specific OELs that are likely to be developed in the near future, but OELs could be developed more expeditiously for nanomaterials by applying dose-response data generated from animal studies for specific nanoparticles across categories of nanomaterials with similar properties and modes of action. This article reviews the history, context, and approaches for developing OELs for particles in general and nanoparticles in particular. Examples of approaches for developing OELs for titanium dioxide and carbon nanotubes are presented and interim OELs from various organizations for some nanomaterials are discussed. When adequate dose-response data are available in animals or humans, quantitative risk assessment methods can provide estimates of adverse health risk of nanomaterials in workers and, in conjunction with workplace exposure and control data, provide a basis for determining appropriate exposure limits. In the absence of adequate quantitative data, qualitative approaches to hazard assessment, exposure control, and safe work practices are prudent measures to reduce hazards in workers.

Granular biodurable nanomaterials: No convincing evidence for systemic toxicity.

PubMed

Moreno-Horn, Marcus; Gebel, Thomas

2014-11-01

Nanomaterials are usually defined by primary particle diameters ranging from 1 to 100 nm. The scope of this review is an evaluation of experimental animal studies dealing with the systemic levels and putative systemic effects induced by nanoparticles which can be characterized as being granular biodurable particles without known specific toxicity (GBP). Relevant examples of such materials comprise nanosized titanium dioxide (TiO2) and carbon black. The question was raised whether GBP nanomaterials systemically accumulate and may possess a relevant systemic toxicity. With few exceptions, the 56 publications reviewed were not performed using established standard protocols, for example, OECD guidelines but used non-standard study designs. The studies including kinetic investigations indicated that GBP nanomaterials were absorbed and systemically distributed to rather low portions only. There was no valid indication that GPB nanomaterials possess novel toxicological hazard properties. In addition, no convincing evidence for a relevant specific systemic toxicity of GBP nanomaterials could be identified. The minority of the papers reviewed (15/56) investigated both nanosized and microsized GBP materials in parallel. A relevant different translocation of GBP nanomaterials in contrast to GBP micromaterials was not observed in these studies. There was no evidence that GPB nanomaterials possess toxicological properties other than their micromaterial counterparts.

Endotoxin Contamination in Nanomaterials Leads to the Misinterpretation of Immunosafety Results

PubMed Central

Li, Yang; Fujita, Mayumi; Boraschi, Diana

2017-01-01

Given the presence of engineered nanomaterials in consumers’ products and their application in nanomedicine, nanosafety assessment is becoming increasingly important. In particular, immunosafety aspects are being actively investigated. In nanomaterial immunosafety testing strategies, it is important to consider that nanomaterials and nanoparticles are very easy to become contaminated with endotoxin, which is a widespread contaminant coming from the Gram-negative bacterial cell membrane. Because of the potent inflammatory activity of endotoxin, contaminated nanomaterials can show inflammatory/toxic effects due to endotoxin, which may mask or misidentify the real biological effects (or lack thereof) of nanomaterials. Therefore, before running immunosafety assays, either in vitro or in vivo, the presence of endotoxin in nanomaterials must be evaluated. This calls for using appropriate assays with proper controls, because many nanomaterials interfere at various levels with the commercially available endotoxin detection methods. This also underlines the need to develop robust and bespoke strategies for endotoxin evaluation in nanomaterials. PMID:28533772

Mechanisms of the oxygen reduction reaction on B- and/or N-doped carbon nanomaterials with curvature and edge effects.

PubMed

Zou, Xiaolong; Wang, Luqing; Yakobson, Boris I

2018-01-18

Despite recent increased research interest in hetero-atom (B and/or N) doping effects on the oxygen reduction reaction (ORR) performance of carbon nanomaterials, microscopic understanding of active catalytic sites and effects of B and/or N doping has not been conclusively reached. Here, through comparative first-principles simulations between BN codoping and isolated B or N doping in both graphene nanoribbons (GNRs) and carbon nanotubes (CNTs), we not only identify active sites in these doped carbon nanomaterials, but elucidate the underlying mechanism of ORR processes. While the distortion of C-C bonds in CNTs leads to strong binding of O 2 , spin density distribution along the edges plays a key role in enhancing the adsorption strength of O 2 on GNRs. The effective adsorption of O 2 facilitates the following elementary reduction reactions. Based on thermodynamic analyses, O 2 adsorption as well as the electron and proton transfer to O atom are identified as key rate-determining steps. For CNTs, a good linear scaling is found between the adsorption energies of key intermediate products and that of atomic O, and thus the latter serves as a good descriptor for ORR activities. Further, N-doped high-quality CNTs are shown to exhibit best performance. For GNRs, due to edge effects, the linear relationship is broken, which promotes the catalytic activities in the BN codoping case. These findings resolve the long-standing controversy on the synergetic effects of B and N codoping, which deepens our understanding of the reaction mechanism. This work might further facilitate the optimization of the doping strategies for high-efficiency carbon-based ORR catalysts.

Engineered Nanomaterials, Sexy New Technology and Potential Hazards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaulieu, R A

Engineered nanomaterials enhance exciting new applications that can greatly benefit society in areas of cancer treatments, solar energy, energy storage, and water purification. While nanotechnology shows incredible promise in these and other areas by exploiting nanomaterials unique properties, these same properties can potentially cause adverse health effects to workers who may be exposed during work. Dispersed nanoparticles in air can cause adverse health effects to animals not merely due to their chemical properties but due to their size, structure, shape, surface chemistry, solubility, carcinogenicity, reproductive toxicity, mutagenicity, dermal toxicity, and parent material toxicity. Nanoparticles have a greater likelihood of lungmore » deposition and blood absorption than larger particles due to their size. Nanomaterials can also pose physical hazards due to their unusually high reactivity, which makes them useful as catalysts, but has the potential to cause fires and explosions. Characterization of the hazards (and potential for exposures) associated with nanomaterial development and incorporation in other products is an essential step in the development of nanotechnologies. Developing controls for these hazards are equally important. Engineered controls should be integrated into nanomaterial manufacturing process design according to 10CFR851, DOE Policy 456.1, and DOE Notice 456.1 as safety-related hardware or administrative controls for worker safety. Nanomaterial hazards in a nuclear facility must also meet control requirements per DOE standards 3009, 1189, and 1186. Integration of safe designs into manufacturing processes for new applications concurrent with the developing technology is essential for worker safety. This paper presents a discussion of nanotechnology, nanomaterial properties/hazards and controls.« less

Synthesis of camptothecin-loaded gold nanomaterials

NASA Astrophysics Data System (ADS)

Xing, Zhimin; Liu, Zhiguo; Zu, Yuangang; Fu, Yujie; Zhao, Chunjian; Zhao, Xiuhua; Meng, Ronghua; Tan, Shengnan

2010-04-01

Camptothecin-loaded gold nanomaterials have been synthesized by the sodium borohydride reduction method under a strong basic condition. The obtained gold nanomaterials have been characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV-vis absorption spectroscopy. The camptothecin-loaded gold colloidal solution was very stable and can be stored for more than two months at room temperature without obvious changes. The color of the colloidal solution can change from wine red to purple and blue during the acidifying process. It was revealed that the release of camptothecin and the aggregation of gold nanoparticles can be controlled by tuning the solution pH. The present study implied that the gold nanomaterials can be used as the potential carrier for CPT delivery.

Nanomaterials in the environment

NASA Astrophysics Data System (ADS)

Mrowiec, Bozena

2017-11-01

This paper considers engineered nanomaterials, deliberately engineered and manufactured to have certain properties and have at least one primary dimension of less than 100 nm. Materials produced with the aid of nanotechnologies are used in many areas of everyday life. Researches with nanomaterials have shown that the physiochemical characteristic of particles can influence their effects in biological systems. The field of nanotechnology has created risk for environment and human health. The toxicity of nanoparticles may be affected by different physicochemical properties, including size, shape, chemistry, surface properties, agglomeration, solubility, and charge, as well as effects from attached functional groups and crystalline structure. The greater surface-area-to-mass ratio of nanoparticles makes them generally more reactive than their macro-sized counterparts. Exposure to nanomaterials can occur at different life-cycle stages of the materials and/or products. The knowledge gaps limiting the understanding of the human and environment hazard and risk of nanotechnology should be explained by the scientific investigations for help to protect human and environmental health and to ensure the benefits of the nanotechnology products without excessive risk of this new technology. In this review are presented the proposal measurement methods for NMs characteristic.

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.

Mechanism of hard-nanomaterial clearance by the liver.

PubMed

Tsoi, Kim M; MacParland, Sonya A; Ma, Xue-Zhong; Spetzler, Vinzent N; Echeverri, Juan; Ouyang, Ben; Fadel, Saleh M; Sykes, Edward A; Goldaracena, Nicolas; Kaths, Johann M; Conneely, John B; Alman, Benjamin A; Selzner, Markus; Ostrowski, Mario A; Adeyi, Oyedele A; Zilman, Anton; McGilvray, Ian D; Chan, Warren C W

2016-11-01

The liver and spleen are major biological barriers to translating nanomedicines because they sequester the majority of administered nanomaterials and prevent delivery to diseased tissue. Here we examined the blood clearance mechanism of administered hard nanomaterials in relation to blood flow dynamics, organ microarchitecture and cellular phenotype. We found that nanomaterial velocity reduces 1,000-fold as they enter and traverse the liver, leading to 7.5 times more nanomaterial interaction with hepatic cells relative to peripheral cells. In the liver, Kupffer cells (84.8 ± 6.4%), hepatic B cells (81.5 ± 9.3%) and liver sinusoidal endothelial cells (64.6 ± 13.7%) interacted with administered PEGylated quantum dots, but splenic macrophages took up less material (25.4 ± 10.1%) due to differences in phenotype. The uptake patterns were similar for two other nanomaterial types and five different surface chemistries. Potential new strategies to overcome off-target nanomaterial accumulation may involve manipulating intra-organ flow dynamics and modulating the cellular phenotype to alter hepatic cell interactions.

Optical and Electronic NOx Sensors for Applications in Mechatronics

PubMed Central

Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A.; Wolter, Scott D.; Brown, April; Ricco, Mario

2009-01-01

Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling. PMID:22412315

TRANSFORMATION AND FATE OF NANOMATERIALS DURING WASTEWATER TREATMENT AND INCINERATION

EPA Science Inventory

This research will produce new data about the characteristics and fate of nanomaterials during biological wastewater treatment and incineration. Such knowledge is necessary for estimating exposure to nanomaterials and developing life cycle risk assessments of nanomaterials. To...

Sequence-Dependent Structure/Function Relationships of Catalytic Peptide-Enabled Gold Nanoparticles Generated under Ambient Synthetic Conditions.

PubMed

Bedford, Nicholas M; Hughes, Zak E; Tang, Zhenghua; Li, Yue; Briggs, Beverly D; Ren, Yang; Swihart, Mark T; Petkov, Valeri G; Naik, Rajesh R; Knecht, Marc R; Walsh, Tiffany R

2016-01-20

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptide-capped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction data and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomic-scale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement.

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.

Simulating the fate and transport of nanomaterials in surface waters

EPA Science Inventory

The unique properties of nanomaterials have resulted in their increased production. However, it is unclear how nanomaterials will move and react once released to the environment One approach for addressing possible exposure of nanomaterials in surface waters is by using numerical...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials.

PubMed

Tan, Chaoliang; Cao, Xiehong; Wu, Xue-Jun; He, Qiyuan; Yang, Jian; Zhang, Xiao; Chen, Junze; Zhao, Wei; Han, Shikui; Nam, Gwang-Hyeon; Sindoro, Melinda; Zhang, Hua

2017-05-10

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocatalysis, batteries, supercapacitors, solar cells, photocatalysis, and sensing platforms. Finally, the challenges and outlooks in this promising field are featured on the basis of its current development.

Chemical Sensing Applications of ZnO Nanomaterials

PubMed Central

Chaudhary, Savita; Umar, Ahmad; Bhasin, K. K.

2018-01-01

Recent advancement in nanoscience and nanotechnology has witnessed numerous triumphs of zinc oxide (ZnO) nanomaterials due to their various exotic and multifunctional properties and wide applications. As a remarkable and functional material, ZnO has attracted extensive scientific and technological attention, as it combines different properties such as high specific surface area, biocompatibility, electrochemical activities, chemical and photochemical stability, high-electron communicating features, non-toxicity, ease of syntheses, and so on. Because of its various interesting properties, ZnO nanomaterials have been used for various applications ranging from electronics to optoelectronics, sensing to biomedical and environmental applications. Further, due to the high electrochemical activities and electron communication features, ZnO nanomaterials are considered as excellent candidates for electrochemical sensors. The present review meticulously introduces the current advancements of ZnO nanomaterial-based chemical sensors. Various operational factors such as the effect of size, morphologies, compositions and their respective working mechanisms along with the selectivity, sensitivity, detection limit, stability, etc., are discussed in this article. PMID:29439528

Redox-responsive theranostic nanoplatforms based on inorganic nanomaterials.

PubMed

Han, Lu; Zhang, Xiao-Yong; Wang, Yu-Long; Li, Xi; Yang, Xiao-Hong; Huang, Min; Hu, Kun; Li, Lu-Hai; Wei, Yen

2017-08-10

Spurred on by advances in materials chemistry and nanotechnology, scientists have developed many novel nanopreparations for cancer diagnosis and therapy. To treat complex malignant tumors effectively, multifunctional nanomedicines with targeting ability, imaging properties and controlled drug release behavior should be designed and exploited. The therapeutic efficiency of loaded drugs can be dramatically improved using redox-responsive nanoplatforms which can sense the differences in the redox status of tumor tissues and healthy ones. Redox-sensitive nanocarriers can be constructed from both organic and inorganic nanomaterials; however, at present, drug delivery nanovectors progressively lean towards inorganic nanomaterials because of their facile synthesis/modification and their unique physicochemical properties. In this review, we focus specifically on the preparation and application of redox-sensitive nanosystems based on mesoporous silica nanoparticles (MSNs), carbon nanomaterials, magnetic nanoparticles, gold nanomaterials and other inorganic nanomaterials. We discuss relevant examples of redox-sensitive nanosystems in each category. Finally, we discuss current challenges and future strategies from the aspect of material design and practical application. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Silicon nanomaterials platform for bioimaging, biosensing, and cancer therapy.

PubMed

Peng, Fei; Su, Yuanyuan; Zhong, Yiling; Fan, Chunhai; Lee, Shuit-Tong; He, Yao

2014-02-18

Silicon nanomaterials are an important class of nanomaterials with great potential for technologies including energy, catalysis, and biotechnology, because of their many unique properties, including biocompatibility, abundance, and unique electronic, optical, and mechanical properties, among others. Silicon nanomaterials are known to have little or no toxicity due to favorable biocompatibility of silicon, which is an important precondition for biological and biomedical applications. In addition, huge surface-to-volume ratios of silicon nanomaterials are responsible for their unique optical, mechanical, or electronic properties, which offer exciting opportunities for design of high-performance silicon-based functional nanoprobes, nanosensors, and nanoagents for biological analysis and detection and disease treatment. Moreover, silicon is the second most abundant element (after oxygen) on earth, providing plentiful and inexpensive resources for large-scale and low-cost preparation of silicon nanomaterials for practical applications. Because of these attractive traits, and in parallel with a growing interest in their design and synthesis, silicon nanomaterials are extensively investigated for wide-ranging applications, including energy, catalysis, optoelectronics, and biology. Among them, bioapplications of silicon nanomaterials are of particular interest. In the past decade, scientists have made an extensive effort to construct a silicon nanomaterials platform for various biological and biomedical applications, such as biosensors, bioimaging, and cancer treatment, as new and powerful tools for disease diagnosis and therapy. Nonetheless, there are few review articles covering these important and promising achievements to promote the awareness of development of silicon nanobiotechnology. In this Account, we summarize recent representative works to highlight the recent developments of silicon functional nanomaterials for a new, powerful platform for biological and

Zn(1-x)MnxTe diluted magnetic semiconductor nanowires grown by molecular beam epitaxy.

PubMed

Zaleszczyk, Wojciech; Janik, Elzbieta; Presz, Adam; Dłuzewski, Piotr; Kret, Sławomir; Szuszkiewicz, Wojciech; Morhange, Jean-François; Dynowska, Elzbieta; Kirmse, Holm; Neumann, Wolfgang; Petroutchik, Aleksy; Baczewski, Lech T; Karczewski, Grzegorz; Wojtowicz, Tomasz

2008-11-01

It is shown that the growth of II-VI diluted magnetic semiconductor nanowires is possible by the catalytically enhanced molecular beam epitaxy (MBE). Zn(1-x)MnxTe NWs with manganese content up to x=0.60 were produced by this method. X-ray diffraction, Raman spectroscopy, and temperature dependent photoluminescence measurements confirm the incorporation of Mn(2+) ions in the cation substitutional sites of the ZnTe matrix of the NWs.

Cellulosic Nanomaterials in Food and Nutraceutical Applications: A Review.

PubMed

Khan, Avik; Wen, Yangbing; Huq, Tanzina; Ni, Yonghao

2018-01-10

Cellulosic nanomaterials (CNMs) are organic, green nanomaterials that are obtained from renewable sources and possess exceptional mechanical strength and biocompatibility. The associated unique physical and chemical properties have made these nanomaterials an intriguing prospect for various applications including the food and nutraceutical industry. From the immobilization of various bioactive agents and enzymes, emulsion stabilization, direct food additives, to the development of intelligent packaging systems or pathogen or pH detectors, the potential food related applications for CNMs are endless. Over the past decade, there have been several reviews published covering different aspects of cellulosic nanomaterials, such as processing-structure-property relationship, physical and chemical properties, rheology, extraction, nanocomposites, etc. In this critical review, we have discussed and provided a summary of the recent developments in the utilization of cellulosic nanomaterials in applications related to food and nutraceuticals.

Comparative assessment of nanomaterial definitions and safety evaluation considerations.

PubMed

Boverhof, Darrell R; Bramante, Christina M; Butala, John H; Clancy, Shaun F; Lafranconi, Mark; West, Jay; Gordon, Steve C

2015-10-01

Nanomaterials continue to bring promising advances to science and technology. In concert have come calls for increased regulatory oversight to ensure their appropriate identification and evaluation, which has led to extensive discussions about nanomaterial definitions. Numerous nanomaterial definitions have been proposed by government, industry, and standards organizations. We conducted a comprehensive comparative assessment of existing nanomaterial definitions put forward by governments to highlight their similarities and differences. We found that the size limits used in different definitions were inconsistent, as were considerations of other elements, including agglomerates and aggregates, distributional thresholds, novel properties, and solubility. Other important differences included consideration of number size distributions versus weight distributions and natural versus intentionally-manufactured materials. Overall, the definitions we compared were not in alignment, which may lead to inconsistent identification and evaluation of nanomaterials and could have adverse impacts on commerce and public perceptions of nanotechnology. We recommend a set of considerations that future discussions of nanomaterial definitions should consider for describing materials and assessing their potential for health and environmental impacts using risk-based approaches within existing assessment frameworks. Our intent is to initiate a dialogue aimed at achieving greater clarity in identifying those nanomaterials that may require additional evaluation, not to propose a formal definition. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Strategies to Improve Cancer Photothermal Therapy Mediated by Nanomaterials.

PubMed

de Melo-Diogo, Duarte; Pais-Silva, Cleide; Dias, Diana R; Moreira, André F; Correia, Ilídio J

2017-05-01

The deployment of hyperthermia-based treatments for cancer therapy has captured the attention of different researchers worldwide. In particular, the application of light-responsive nanomaterials to mediate hyperthermia has revealed promising results in several pre-clinical assays. Unlike conventional therapies, these nanostructures can display a preferential tumor accumulation and thus mediate, upon irradiation with near-infrared light, a selective hyperthermic effect with temporal resolution. Different types of nanomaterials such as those based on gold, carbon, copper, molybdenum, tungsten, iron, palladium and conjugated polymers have been used for this photothermal modality. This progress report summarizes the different strategies that have been applied so far for increasing the efficacy of the photothermal therapeutic effect mediated by nanomaterials, namely those that improve the accumulation of nanomaterials in tumors (e.g. by changing the corona composition or through the functionalization with targeting ligands), increase nanomaterials' intrinsic capacity to generate photoinduced heat (e.g. by synthesizing new nanomaterials or assembling nanostructures) or by optimizing the parameters related to the laser light used in the irradiation process (e.g. by modulating the radiation wavelength). Overall, the development of new strategies or the optimization and combination of the existing ones will surely give a major contribution for the application of nanomaterials in cancer PTT. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[International trend of guidance for nanomaterial risk assessment].

PubMed

Hirose, Akihiko

2013-01-01

In the past few years, several kinds of opinions or recommendations on the nanomaterial safety assessment have been published from international or national bodies. Among the reports, the first practical guidance of risk assessment from the regulatory body was published from the European Food Safety Authorities in May 2011, which included the determination of exposure scenario and toxicity testing strategy. In October 2011, European Commission (EC) adopted the definition of "nanomaterial" for regulation. And more recently, Scientific Committee on Consumer Safety of EC released guidance for assessment of nanomaterials in cosmetics in June 2012. A series of activities in EU marks an important step towards realistic safety assessment of nanomaterials. On the other hand, the US FDA announced a draft guidance for industry in June 2011, and then published draft guidance documents for both "Cosmetic Products" and "Food Ingredients and Food Contact Substances" in April 2012. These draft documents do not restrictedly define the physical properties of nanomaterials, but when manufacturing changes alter the dimensions, properties, or effects of an FDA-regulated product, the products are treated as new products. Such international movements indicate that most of nanomaterials with any new properties would be assessed or regulated as new products by most of national authorities in near future, although the approaches are still case by case basis. We will introduce such current international activities and consideration points for regulatory risk assessment.

Nanomaterial Toxicity Screening in Developing Zebrafish Embryos

EPA Science Inventory

To assess nanomaterial vertebrate toxicity, a high-content screening assay was created using developing zebrafish, Danio rerio. This included a diverse group of nanomaterials (n=42 total) ranging from metallic (Ag, Au) and metal oxide (CeO2, CuO, TiO2, ZnO) nanoparticles, to non...

Safety and toxicity of nanomaterials for ocular drug delivery applications.

PubMed

Mehra, Neelesh K; Cai, Defu; Kuo, Lih; Hein, Travis; Palakurthi, Srinath

2016-09-01

Multifunctional nanomaterials are rapidly emerging for ophthalmic delivery of therapeutics to facilitate safe and effective targeting with improved patient compliance. Because of their extremely high area to volume ratio, nanomaterials often have physicochemical properties that are different from those of their larger counterparts. There exists a complex relationship between the physicochemical properties (composition, size, shape, charge, roughness, and porosity) of the nanomaterials and their interaction with the biological system. The eye is a very sensitive accessible organ and is subjected to intended and unintended exposure to nanomaterials. Currently, various ophthalmic formulations are available in the market, while some are underway in preclinical and clinical phases. However, the data on safety, efficacy, and toxicology of these advanced nanomaterials for ocular drug delivery are sparse. Focus of the present review is to provide a comprehensive report on the safety, biocompatibility and toxicities of nanomaterials in the eye.

Expanding Applications of SERS through Versatile Nanomaterials Engineering (Postprint)

DTIC Science & Technology

2017-06-22

AFRL-RX-WP-JA-2017-0341 EXPANDING APPLICATIONS OF SERS THROUGH VERSATILE NANOMATERIALS ENGINEERING (POSTPRINT) M. Fernanda...AND SUBTITLE EXPANDING APPLICATIONS OF SERS THROUGH VERSATILE NANOMATERIALS ENGINEERING (POSTPRINT) 5a. CONTRACT NUMBER FA8650-15-2-5518 5b...Expanding applications of SERS through versatile nanomaterials engineering M. Fernanda Cardinal, Emma Vander Ende, Ryan A. Hackler, Michael O. McAnally

Two dimensional nanomaterials for flexible supercapacitors.

PubMed

Peng, Xu; Peng, Lele; Wu, Changzheng; Xie, Yi

2014-05-21

Flexible supercapacitors, as one of most promising emerging energy storage devices, are of great interest owing to their high power density with great mechanical compliance, making them very suitable as power back-ups for future stretchable electronics. Two-dimensional (2D) nanomaterials, including the quasi-2D graphene and inorganic graphene-like materials (IGMs), have been greatly explored to providing huge potential for the development of flexible supercapacitors with higher electrochemical performance. This review article is devoted to recent progresses in engineering 2D nanomaterials for flexible supercapacitors, which survey the evolution of electrode materials, recent developments in 2D nanomaterials and their hybrid nanostructures with regulated electrical properties, and the new planar configurations of flexible supercapacitors. Furthermore, a brief discussion on future directions, challenges and opportunities in this fascinating area is also provided.

Overview of Risk Management for Engineered Nanomaterials

NASA Astrophysics Data System (ADS)

Schulte, P. A.; Geraci, C. L.; Hodson, L. L.; Zumwalde, R. D.; Kuempel, E. D.; Murashov, V.; Martinez, K. F.; Heidel, D. S.

2013-04-01

Occupational exposure to engineered nanomaterials (ENMs) is considered a new and challenging occurrence. Preliminary information from laboratory studies indicates that workers exposed to some kinds of ENMs could be at risk of adverse health effects. To protect the nanomaterial workforce, a precautionary risk management approach is warranted and given the newness of ENMs and emergence of nanotechnology, a naturalistic view of risk management is useful. Employers have the primary responsibility for providing a safe and healthy workplace. This is achieved by identifying and managing risks which include recognition of hazards, assessing exposures, characterizing actual risk, and implementing measures to control those risks. Following traditional risk management models for nanomaterials is challenging because of uncertainties about the nature of hazards, issues in exposure assessment, questions about appropriate control methods, and lack of occupational exposure limits (OELs) or nano-specific regulations. In the absence of OELs specific for nanomaterials, a precautionary approach has been recommended in many countries. The precautionary approach entails minimizing exposures by using engineering controls and personal protective equipment (PPE). Generally, risk management utilizes the hierarchy of controls. Ideally, risk management for nanomaterials should be part of an enterprise-wide risk management program or system and this should include both risk control and a medical surveillance program that assesses the frequency of adverse effects among groups of workers exposed to nanomaterials. In some cases, the medical surveillance could include medical screening of individual workers to detect early signs of work-related illnesses. All medical surveillance should be used to assess the effectiveness of risk management; however, medical surveillance should be considered as a second line of defense to ensure that implemented risk management practices are effective.

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.

[Degradation and transformation of engineering carbon nanomaterials in the environment: A review].

PubMed

Yue, Fang-Ning; Luo, Shui-Ming; Zhang, Cheng-Dong

2013-02-01

With the large amount production and application of engineering carbon nanomaterials, their potential ecological risk has attracted extensive attention. The degradation and transformation of the carbon nanomaterials in the environment directly affect the fates and eco-toxicity of the nanomaterials in the environment, and the research of the degradation and transformation processes of the nanomaterials in the environment is the key link for the determination of the environmental capacity of the nanomaterials and for the evaluation of the nanomaterials life cycle in the environment. This paper briefly introduced the chemical transformation, microbial degradation, and photodegradation of the major engineering carbon nanomaterials (carbon nanotubes and fullerene) in the environment, and summarized the environmental and structural factors affecting the degradation of the nanomaterials and the related intrinsic mechanisms. The shortcomings of the related researches and the directions of the future research were also put forward.

Toxicology and cellular effect of manufactured nanomaterials

DOEpatents

Chen, Fanqing

2014-07-22

The increasing use of nanotechnology in consumer products and medical applications underlies the importance of understanding its potential toxic effects to people and the environment. Herein are described methods and assays to predict and evaluate the cellular effects of nanomaterial exposure. Exposing cells to nanomaterials at cytotoxic doses induces cell cycle arrest and increases apoptosis/necrosis, activates genes involved in cellular transport, metabolism, cell cycle regulation, and stress response. Certain nanomaterials induce genes indicative of a strong immune and inflammatory response within skin fibroblasts. Furthermore, the described multiwall carbon nanoonions (MWCNOs) can be used as a therapeutic in the treatment of cancer due to its cytotoxicity.

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.

Recent advances in nanomaterial-based biosensors for antibiotics detection.

PubMed

Lan, Lingyi; Yao, Yao; Ping, Jianfeng; Ying, Yibin

2017-05-15

Antibiotics are able to be accumulated in human body by food chain and may induce severe influence to human health and safety. Hence, the development of sensitive and simple methods for rapid evaluation of antibiotic levels is highly desirable. Nanomaterials with excellent electronic, optical, mechanical, and thermal properties have been recognized as one of the most promising materials for opening new gates in the development of next-generation biosensors. This review highlights the current advances in the nanomaterial-based biosensors for antibiotics detection. Different kinds of nanomaterials including carbon nanomaterials, metal nanomaterials, magnetic nanoparticles, up-conversion nanoparticles, and quantum dots have been applied to the construction of biosensors with two main signal-transducing mechanisms, i.e. optical and electrochemical. Furthermore, the current challenges and future prospects in this field are also included to provide an overview for future research directions. Copyright © 2017 Elsevier B.V. All rights reserved.

Biopharmaceutics and Therapeutic Potential of Engineered Nanomaterials

PubMed Central

Liang, Xing-Jie; Chen, Chunying; Zhao, Yuliang; Jia, Lee; Wang, Paul C.

2009-01-01

Engineered nanomaterials are at the leading edge of the rapidly developing nanosciences and are founding an important class of new materials with specific physicochemical properties different from bulk materials with the same compositions. The potential for nanomaterials is rapidly expanding with novel applications constantly being explored in different areas. The unique size-dependent properties of nanomaterials make them very attractive for pharmaceutical applications. Investigations of physical, chemical and biological properties of engineered nanomaterials have yielded valuable information. Cytotoxic effects of certain engineered nanomaterials towards malignant cells form the basis for one aspect of nanomedicine. It is inferred that size, three dimensional shape, hydrophobicity and electronic configurations make them an appealing subject in medicinal chemistry. Their unique structure coupled with immense scope for derivatization forms a base for exciting developments in therapeutics. This review article addresses the fate of absorption, distribution, metabolism and excretion (ADME) of engineered nanoparticles in vitro and in vivo. It updates the distinctive methodology used for studying the biopharmaceutics of nanoparticles. This review addresses the future potential and safety concerns and genotoxicity of nanoparticle formulations in general. It particularly emphasizes the effects of nanoparticles on metabolic enzymes as well as the parenteral or inhalation administration routes of nanoparticle formulations. This paper illustrates the potential of nanomedicine by discussing biopharmaceutics of fullerene derivatives and their suitability for diagnostic and therapeutic purposes. Future direction is discussed as well. PMID:18855608

“NaKnowBase”: A Nanomaterials Relational Database

EPA Science Inventory

NaKnowBase is an internal relational database populated with data from peer-reviewed ORD nanomaterials research publications. The database focuses on papers describing the actions of nanomaterials in environmental or biological media including their interactions, transformations...

First-Principles Approach to Energy Level Alignment at Aqueous Semiconductor Interfaces

NASA Astrophysics Data System (ADS)

Hybertsen, Mark

2015-03-01

We have developed a first principles method to calculate the energy level alignment between semiconductor band edges and reference energy levels at aqueous interfaces. This alignment is fundamental to understand the electrochemical characteristics of any semiconductor electrode in general and the potential for photocatalytic activity in particular. For example, in the search for new photo-catalytic materials, viable candidates must demonstrate both efficient absorption of the solar spectrum and an appropriate alignment of the band edge levels in the semiconductor to the redox levels for the target reactions. In our approach, the interface-specific contribution to the electrostatic step across the interface is evaluated using density functional theory (DFT) based molecular dynamics to sample the physical interface structure and the corresponding change in the electrostatic potential at the interface. The reference electronic levels in the semiconductor and in the water are calculated using the GW approach, which naturally corrects for errors inherent in the use of Kohn-Sham energy eigenvalues to approximate the electronic excitation energies in each material. Taken together, our calculations provide the alignment of the semiconductor valence band edge to the centroid of the highest occupied 1b1 level in water. The known relationship of the 1b1 level to the normal hydrogen electrode completes the connection to electrochemical levels. We discuss specific results for GaN, ZnO, and TiO2. The effect of interface structural motifs, such as different degrees of water dissociation, and of dynamical characteristics, will be presented together with available experimental data. Work supported by the US Department of Energy, Office of Basic Energy Sciences under Contract No. DE-AC02-98CH10886.

Cellulose-Based Nanomaterials for Energy Applications.

PubMed

Wang, Xudong; Yao, Chunhua; Wang, Fei; Li, Zhaodong

2017-11-01

Cellulose is the most abundant natural polymer on earth, providing a sustainable green resource that is renewable, degradable, biocompatible, and cost effective. Recently, nanocellulose-based mesoporous structures, flexible thin films, fibers, and networks are increasingly developed and used in photovoltaic devices, energy storage systems, mechanical energy harvesters, and catalysts components, showing tremendous materials science value and application potential in many energy-related fields. In this Review, the most recent advancements of processing, integration, and application of cellulose nanomaterials in the areas of solar energy harvesting, energy storage, and mechanical energy harvesting are reviewed. For solar energy harvesting, promising applications of cellulose-based nanostructures for both solar cells and photoelectrochemical electrodes development are reviewed, and their morphology-related merits are discussed. For energy storage, the discussion is primarily focused on the applications of cellulose-based nanomaterials in lithium-ion batteries, including electrodes (e.g., active materials, binders, and structural support), electrolytes, and separators. Applications of cellulose nanomaterials in supercapacitors are also reviewed briefly. For mechanical energy harvesting, the most recent technology evolution in cellulose-based triboelectric nanogenerators is reviewed, from fundamental property tuning to practical implementations. At last, the future research potential and opportunities of cellulose nanomaterials as a new energy material are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Applications of nanomaterials as vaccine adjuvants

PubMed Central

Zhu, Motao; Wang, Rongfu; Nie, Guangjun

2014-01-01

Vaccine adjuvants are applied to amplify the recipient's specific immune responses against pathogen infection or malignancy. A new generation of adjuvants is being developed to meet the demands for more potent antigen-specific responses, specific types of immune responses, and a high margin of safety. Nanotechnology provides a multifunctional stage for the integration of desired adjuvant activities performed by the building blocks of tailor-designed nanoparticles. Using nanomaterials for antigen delivery can provide high bioavailability, sustained and controlled release profiles, and targeting and imaging properties resulting from manipulation of the nanomaterials’ physicochemical properties. Moreover, the inherent immune-regulating activity of particular nanomaterials can further promote and shape the cellular and humoral immune responses toward desired types. The combination of both the delivery function and immunomodulatory effect of nanomaterials as adjuvants is thought to largely benefit the immune outcomes of vaccination. In this review, we will address the current achievements of nanotechnology in the development of novel adjuvants. The potential mechanisms by which nanomaterials impact the immune responses to a vaccine and how physicochemical properties, including size, surface charge and surface modification, impact their resulting immunological outcomes will be discussed. This review aims to provide concentrated information to promote new insights for the development of novel vaccine adjuvants. PMID:25483497

Transmission electron microscopy artifacts in characterization of the nanomaterial-cell interactions.

PubMed

Leung, Yu Hang; Guo, Mu Yao; Ma, Angel P Y; Ng, Alan M C; Djurišić, Aleksandra B; Degger, Natalie; Leung, Frederick C C

2017-07-01

We investigated transmission electron microscopy artifacts obtained using standard sample preparation protocols applied to the investigation of Escherichia coli cells exposed to common nanomaterials, such as TiO 2 , Ag, ZnO, and MgO. While the common protocols for some nanomaterials result only in known issues of nanomaterial-independent generation of anomalous deposits due to fixation and staining, for others, there are reactions between the nanomaterial and chemicals used for post-fixation or staining. Only in the case of TiO 2 do we observe only the known issues of nanomaterial-independent generation of anomalous deposits due to exceptional chemical stability of this material. For the other three nanomaterials, different artifacts are observed. For each of those, we identify causes of the observed problems and suggest alternative sample preparation protocols to avoid artifacts arising from the sample preparation, which is essential for correct interpretation of the obtained images and drawing correct conclusions on cell-nanomaterial interactions. Finally, we propose modified sample preparation and characterization protocols for comprehensive and conclusive investigations of nanomaterial-cell interactions using electron microscopy and for obtaining clear and unambiguous revelation whether the nanomaterials studied penetrate the cells or accumulate at the cell membranes. In only the case of MgO and ZnO, the unambiguous presence of Zn and Mg could be observed inside the cells.

“NaKnowBase”: A Nanomaterials Relational Database

EPA Science Inventory

NaKnowBase is a relational database populated with data from peer-reviewed ORD nanomaterials research publications. The database focuses on papers describing the actions of nanomaterials in environmental or biological media including their interactions, transformations and poten...

Ripening of Semiconductor Nanoplatelets.

PubMed

Ott, Florian D; Riedinger, Andreas; Ochsenbein, David R; Knüsel, Philippe N; Erwin, Steven C; Mazzotti, Marco; Norris, David J

2017-11-08

Ostwald ripening describes how the size distribution of colloidal particles evolves with time due to thermodynamic driving forces. Typically, small particles shrink and provide material to larger particles, which leads to size defocusing. Semiconductor nanoplatelets, thin quasi-two-dimensional (2D) particles with thicknesses of only a few atomic layers but larger lateral dimensions, offer a unique system to investigate this phenomenon. Experiments show that the distribution of nanoplatelet thicknesses does not defocus during ripening, but instead jumps sequentially from m to (m + 1) monolayers, allowing precise thickness control. We investigate how this counterintuitive process occurs in CdSe nanoplatelets. We develop a microscopic model that treats the kinetics and thermodynamics of attachment and detachment of monomers as a function of their concentration. We then simulate the growth process from nucleation through ripening. For a given thickness, we observe Ostwald ripening in the lateral direction, but none perpendicular. Thicker populations arise instead from nuclei that capture material from thinner nanoplatelets as they dissolve laterally. Optical experiments that attempt to track the thickness and lateral extent of nanoplatelets during ripening appear consistent with these conclusions. Understanding such effects can lead to better synthetic control, enabling further exploration of quasi-2D nanomaterials.

Nanomaterials as analytical tools for genosensors.

PubMed

Abu-Salah, Khalid M; Alrokyan, Salman A; Khan, Muhammad Naziruddin; Ansari, Anees Ahmad

2010-01-01

Nanomaterials are being increasingly used for the development of electrochemical DNA biosensors, due to the unique electrocatalytic properties found in nanoscale materials. They offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bioelectronic devices exhibiting novel functions. In particular, nanomaterials such as noble metal nanoparticles (Au, Pt), carbon nanotubes (CNTs), magnetic nanoparticles, quantum dots and metal oxide nanoparticles have been actively investigated for their applications in DNA biosensors, which have become a new interdisciplinary frontier between biological detection and material science. In this article, we address some of the main advances in this field over the past few years, discussing the issues and challenges with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination.

Nanomaterials as Analytical Tools for Genosensors

PubMed Central

Abu-Salah, Khalid M.; Alrokyan, Salman A.; Khan, Muhammad Naziruddin; Ansari, Anees Ahmad

2010-01-01

Nanomaterials are being increasingly used for the development of electrochemical DNA biosensors, due to the unique electrocatalytic properties found in nanoscale materials. They offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bioelectronic devices exhibiting novel functions. In particular, nanomaterials such as noble metal nanoparticles (Au, Pt), carbon nanotubes (CNTs), magnetic nanoparticles, quantum dots and metal oxide nanoparticles have been actively investigated for their applications in DNA biosensors, which have become a new interdisciplinary frontier between biological detection and material science. In this article, we address some of the main advances in this field over the past few years, discussing the issues and challenges with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination. PMID:22315580

Optical determination of crystal phase in semiconductor nanocrystals

PubMed Central

Lim, Sung Jun; Schleife, André; Smith, Andrew M.

2017-01-01

Optical, electronic and structural properties of nanocrystals fundamentally derive from crystal phase. This is especially important for polymorphic II–VI, III–V and I-III-VI2 semiconductor materials such as cadmium selenide, which exist as two stable phases, cubic and hexagonal, each with distinct properties. However, standard crystallographic characterization through diffraction yields ambiguous phase signatures when nanocrystals are small or polytypic. Moreover, diffraction methods are low-throughput, incompatible with solution samples and require large sample quantities. Here we report the identification of unambiguous optical signatures of cubic and hexagonal phases in II–VI nanocrystals using absorption spectroscopy and first-principles electronic-structure theory. High-energy spectral features allow rapid identification of phase, even in small nanocrystals (∼2 nm), and may help predict polytypic nanocrystals from differential phase contributions. These theoretical and experimental insights provide simple and accurate optical crystallographic analysis for liquid-dispersed nanomaterials, to improve the precision of nanocrystal engineering and improve our understanding of nanocrystal reactions. PMID:28513577

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.

Mesoporous carbon nanomaterials in drug delivery and biomedical application.

PubMed

Zhao, Qinfu; Lin, Yuanzhe; Han, Ning; Li, Xian; Geng, Hongjian; Wang, Xiudan; Cui, Yu; Wang, Siling

2017-01-01

Recent development of nano-technology provides highly efficient and versatile treatment methods to achieve better therapeutic efficacy and lower side effects of malignant cancer. The exploration of drug delivery systems (DDSs) based on nano-material shows great promise in translating nano-technology to clinical use to benefit patients. As an emerging inorganic nanomaterial, mesoporous carbon nanomaterials (MCNs) possess both the mesoporous structure and the carbonaceous composition, endowing them with superior nature compared with mesoporous silica nanomaterials and other carbon-based materials, such as carbon nanotube, graphene and fullerene. In this review, we highlighted the cutting-edge progress of carbon nanomaterials as drug delivery systems (DDSs), including immediate/sustained drug delivery systems and controlled/targeted drug delivery systems. In addition, several representative biomedical applications of mesoporous carbon such as (1) photo-chemo synergistic therapy; (2) delivery of therapeutic biomolecule and (3) in vivo bioimaging are discussed and integrated. Finally, potential challenges and outlook for future development of mesoporous carbon in biomedical fields have been discussed in detail.

A practical approach to determine dose metrics for nanomaterials.

PubMed

Delmaar, Christiaan J E; Peijnenburg, Willie J G M; Oomen, Agnes G; Chen, Jingwen; de Jong, Wim H; Sips, Adriënne J A M; Wang, Zhuang; Park, Margriet V D Z

2015-05-01

Traditionally, administered mass is used to describe doses of conventional chemical substances in toxicity studies. For deriving toxic doses of nanomaterials, mass and chemical composition alone may not adequately describe the dose, because particles with the same chemical composition can have completely different toxic mass doses depending on properties such as particle size. Other dose metrics such as particle number, volume, or surface area have been suggested, but consensus is lacking. The discussion regarding the most adequate dose metric for nanomaterials clearly needs a systematic, unbiased approach to determine the most appropriate dose metric for nanomaterials. In the present study, the authors propose such an approach and apply it to results from in vitro and in vivo experiments with silver and silica nanomaterials. The proposed approach is shown to provide a convenient tool to systematically investigate and interpret dose metrics of nanomaterials. Recommendations for study designs aimed at investigating dose metrics are provided. © 2015 SETAC.

Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

PubMed Central

Dierking, Ingo

2017-01-01

Liquid crystals are an integral part of a mature display technology, also establishing themselves in other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors, just to name a few of the non-display applications. In recent years, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i) addition of nanomaterials can change and thus tune the properties of the liquid crystal; (ii) novel functionalities can be added to the liquid crystal; and (iii) the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research effort has been concentrated on thermotropic systems, which change order as a function of temperature. Here we review the other side of the medal, the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids. Several classes of materials will be discussed, inorganic and mineral liquid crystals, viruses, nanotubes and nanorods, as well as graphene oxide. PMID:28974025

Current Trends in Nanomaterial-Based Amperometric Biosensors

PubMed Central

Hayat, Akhtar; Catanante, Gaëlle; Marty, Jean Louis

2014-01-01

The last decade has witnessed an intensive research effort in the field of electrochemical sensors, with a particular focus on the design of amperometric biosensors for diverse analytical applications. In this context, nanomaterial integration in the construction of amperometric biosensors may constitute one of the most exciting approaches. The attractive properties of nanomaterials have paved the way for the design of a wide variety of biosensors based on various electrochemical detection methods to enhance the analytical characteristics. However, most of these nanostructured materials are not explored in the design of amperometric biosensors. This review aims to provide insight into the diverse properties of nanomaterials that can be possibly explored in the construction of amperometric biosensors. PMID:25494347

Effects of Copper Nanomaterials on Marine Benthic Communities

EPA Science Inventory

Copper nanomaterials (CuNMs) are used as an anti-bacterial and anti-fouling agent in numerous commercial and industrial products, including water purifiers, fungicides, wood and touch surfaces. The widespread popularity of copper nanomaterials in consumer products increases the r...

An overview of nanomaterials applied for removing dyes from wastewater.

PubMed

Cai, Zhengqing; Sun, Youmin; Liu, Wen; Pan, Fei; Sun, Peizhe; Fu, Jie

2017-07-01

Organic dyes are one of the most commonly discharged pollutants in wastewaters; however, many conventional treatment methods cannot treat them effectively. Over the past few decades, we have witnessed rapid development of nanotechnologies, which offered new opportunities for developing innovative methods to treat dye-contaminated wastewater with low price and high efficiency. The large surface area, modified surface properties, unique electron conduction properties, etc. offer nanomaterials with excellent performances in dye-contaminated wastewater treatment. For examples, the agar-modified monometallic/bimetallic nanoparticles have the maximum methylene blue adsorption capacity of 875.0 mg/g, which are several times higher than conventional adsorbents. Among various nanomaterials, the carbonaceous nanomaterials, nano-sized TiO 2 , and graphitic carbon nitride (g-C 3 N 4 ) are considered as the most promising nanomaterials for removing dyes from water phase. However, some challenges, such as high cost and poor separation performance, still limit their engineering application. This article reviewed the recent advances in the nanomaterials used for dye removal via adsorption, photocatalytic degradation, and biological treatment. The modification methods for improving the effectiveness of nanomaterials are highlighted. Finally, the current knowledge gaps of developing nanomaterials on the environmental application were discussed, and the possible further research direction is proposed.

Synchrotron-based X-ray microscopic studies for bioeffects of nanomaterials.

PubMed

Zhu, Ying; Cai, Xiaoqing; Li, Jiang; Zhong, Zengtao; Huang, Qing; Fan, Chunhai

2014-04-01

There have been increasing interests in studying biological effects of nanomaterials, which are nevertheless faced up with many challenges due to the nanoscale dimensions and unique chemical properties of nanomaterials. Synchrotron-based X-ray microscopy, an advanced imaging technology with high spatial resolution and excellent elemental specificity, provides a new platform for studying interactions between nanomaterials and living systems. In this article, we review the recent progress of X-ray microscopic studies on bioeffects of nanomaterials in several living systems including cells, model organisms, animals and plants. We aim to provide an overview of the state of the art, and the advantages of using synchrotron-based X-ray microscopy for characterizing in vitro and in vivo behaviors and biodistribution of nanomaterials. We also expect that the use of a combination of new synchrotron techniques should offer unprecedented opportunities for better understanding complex interactions at the nano-biological interface and accounting for unique bioeffects of nanomaterials. Synchrotron-based X-ray microscopy is a non-destructive imaging technique that enables high resolution spatial mapping of metals with elemental level detection methods. This review summarizes the current use and perspectives of this novel technique in studying the biology and tissue interactions of nanomaterials. Copyright © 2014 Elsevier Inc. All rights reserved.

Eating nanomaterials: cruelty-free and safe? the EFSA guidance on risk assessment of nanomaterials in food and feed.

PubMed

Sauer, Ursula G

2011-12-01

Nanomaterials are increasingly being added to food handling and packaging materials, or directly, to human food and animal feed. To ensure the safety of such engineered nanomaterials (ENMs), in May 2011, the European Food Safety Authority (EFSA) published a guidance document on Risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain. It states that risk assessment should be performed by following a step-wise procedure. Whenever human or animal exposure to nanomaterials is expected, the general hazard characterisation scheme requests information from in vitro genotoxicity, toxicokinetic and repeated dose 90-day oral toxicity studies in rodents. Numerous prevailing uncertainties with regard to nanomaterial characterisation and their hazard and risk assessment are addressed in the guidance document. This article discusses the impact of these knowledge gaps on meeting the goal of ensuring human safety. The EFSA's guidance on the risk assessment of ENMs in food and animal feed is taken as an example for discussion, from the point of view of animal welfare, on what level of uncertainty should be considered acceptable for human safety assessment of products with non-medical applications, and whether animal testing should be considered ethically acceptable for such products.

The formation mechanism of binary semiconductor nanomaterials: shared by single-source and dual-source precursor approaches.

PubMed

Yu, Kui; Liu, Xiangyang; Zeng, Qun; Yang, Mingli; Ouyang, Jianying; Wang, Xinqin; Tao, Ye

2013-10-11

One thing in common: The formation of binary colloidal semiconductor nanocrystals from single- (M(EEPPh2 )n ) and dual-source precursors (metal carboxylates M(OOCR)n and phosphine chalcogenides such as E=PHPh2 ) is found to proceed through a common mechanism. For CdSe as a model system (31) P NMR spectroscopy and DFT calculations support a reaction mechanism which includes numerous metathesis equilibriums and Se exchange reactions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Toxicity, Uptake, and Translocation of Engineered Nanomaterials in Vascular plants.

PubMed

Miralles, Pola; Church, Tamara L; Harris, Andrew T

2012-09-04

To exploit the promised benefits of engineered nanomaterials, it is necessary to improve our knowledge of their bioavailability and toxicity. The interactions between engineered nanomaterials and vascular plants are of particular concern, as plants closely interact with soil, water, and the atmosphere, and constitute one of the main routes of exposure for higher species, i.e. accumulation through the food chain. A review of the current literature shows contradictory evidence on the phytotoxicity of engineered nanomaterials. The mechanisms by which engineered nanomaterials penetrate plants are not well understood, and further research on their interactions with vascular plants is required to enable the field of phytotoxicology to keep pace with that of nanotechnology, the rapid evolution of which constantly produces new materials and applications that accelerate the environmental release of nanomaterials.

Mobility of coated and uncoated TiO2 nanomaterials in soil columns--Applicability of the tests methods of OECD TG 312 and 106 for nanomaterials.

PubMed

Nickel, Carmen; Gabsch, Stephan; Hellack, Bryan; Nogowski, Andre; Babick, Frank; Stintz, Michael; Kuhlbusch, Thomas A J

2015-07-01

Nanomaterials are commonly used in everyday life products and during their life cycle they can be released into the environment. Soils and sediments are estimated as significant sinks for those nanomaterials. To investigate and assess the behaviour of nanomaterials in soils and sediments standardized test methods are needed. In this study the applicability of two existing international standardized test guidelines for the testing of nanomaterials, OECD TG 106 "Adsorption/Desorption using a Bath Equilibrium Method" and the OECD TG 312 "Leaching in Soil Columns", were investigated. For the study one coated and two uncoated TiO2 nanomaterials were used, respectively. The results indicate that the OECD TG 106 is not applicable for nanomaterials. However, the test method according to OECD TG 312 was found to be applicable if nano-specific adaptations are applied. The mobility investigations of the OECD TG 312 indicated a material-dependent mobility of the nanomaterials, which in some cases may lead to an accumulation in the upper soil layers. Whereas no significant transport was observed for the uncoated materials for the double-coated material (coating with dimethicone and aluminiumoxide) a significant transport was detected and attributed to the coating. Copyright © 2015 Elsevier Ltd. All rights reserved.

Two-Dimensional Nanomaterials for Biomedical Applications: Emerging Trends and Future Prospects.

PubMed

Chimene, David; Alge, Daniel L; Gaharwar, Akhilesh K

2015-12-02

Two-dimensional (2D) nanomaterials are ultrathin nanomaterials with a high degree of anisotropy and chemical functionality. Research on 2D nanomaterials is still in its infancy, with the majority of research focusing on elucidating unique material characteristics and few reports focusing on biomedical applications of 2D nanomaterials. Nevertheless, recent rapid advances in 2D nanomaterials have raised important and exciting questions about their interactions with biological moieties. 2D nanoparticles such as carbon-based 2D materials, silicate clays, transition metal dichalcogenides (TMDs), and transition metal oxides (TMOs) provide enhanced physical, chemical, and biological functionality owing to their uniform shapes, high surface-to-volume ratios, and surface charge. Here, we focus on state-of-the-art biomedical applications of 2D nanomaterials as well as recent developments that are shaping this emerging field. Specifically, we describe the unique characteristics that make 2D nanoparticles so valuable, as well as the biocompatibility framework that has been investigated so far. Finally, to both capture the growing trend of 2D nanomaterials for biomedical applications and to identify promising new research directions, we provide a critical evaluation of potential applications of recently developed 2D nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sequence-Dependent Structure/Function Relationships of Catalytic Peptide-Enabled Gold Nanoparticles Generated under Ambient Synthetic Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bedford, Nicholas M.; Hughes, Zak E.; Tang, Zhenghua

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptide-capped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction datamore » and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomic-scale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement.« less

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

Carbon nanomaterials for non-volatile memories

NASA Astrophysics Data System (ADS)

Ahn, Ethan C.; Wong, H.-S. Philip; Pop, Eric

2018-03-01

Carbon can create various low-dimensional nanostructures with remarkable electronic, optical, mechanical and thermal properties. These features make carbon nanomaterials especially interesting for next-generation memory and storage devices, such as resistive random access memory, phase-change memory, spin-transfer-torque magnetic random access memory and ferroelectric random access memory. Non-volatile memories greatly benefit from the use of carbon nanomaterials in terms of bit density and energy efficiency. In this Review, we discuss sp2-hybridized carbon-based low-dimensional nanostructures, such as fullerene, carbon nanotubes and graphene, in the context of non-volatile memory devices and architectures. Applications of carbon nanomaterials as memory electrodes, interfacial engineering layers, resistive-switching media, and scalable, high-performance memory selectors are investigated. Finally, we compare the different memory technologies in terms of writing energy and time, and highlight major challenges in the manufacturing, integration and understanding of the physical mechanisms and material properties.

Emerging roles of engineered nanomaterials in the food industry.

PubMed

Morris, V J

2011-10-01

Nanoscience is the study of phenomena and the manipulation of materials at the atomic or molecular level. Nanotechnology involves the design, production and use of structures through control of the size and shape of the materials at the nanometre scale. Nanotechnology in the food sector is an emerging area with considerable research and potential products. There is particular interest in the definition and regulation of engineered nanomaterials. This term covers three classes of nanomaterials: natural and processed nanostructures in foods; particulate nanomaterials metabolized or excreted on digestion; and particulate nanomaterials not broken down on digestion, which accumulate in the body. This review describes examples of these classes and their likely status in the food industry. Copyright © 2011 Elsevier Ltd. All rights reserved.

Nanomaterials driven energy, environmental and biomedical research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Prakash C.; Srinivasan, Sesha S.; Wilson, Jeremiah F.

We have developed state-of-the-art nanomaterials such as nanofibers, nanotubes, nanoparticles, nanocatalysts and nanostructures for clean energy, environmental and biomedical research. Energy can neither be created nor be destroyed, but it can be converted from one form to another. Based on this principle, chemical energy such as hydrogen has been produced from water electrolysis at a much lower voltage using RuO{sub 2} nanoparticles on the Si wafer substrate. Once the hydrogen is produced from the clean sources such as solar energy and water, it has to be stored by physisorption or chemisorption processes on to the solid state systems. For themore » successful physical adsorption of hydrogen molecule, we have developed novel polyaniline nanostructures via chemical templating and electrospinning routes. Chemical or complex hydrides involving nano MgH{sub 2} and transition metal nanocatalysts have been synthesized to tailor both the thermodynamics and kinetics of hydrogen (chemi) sorption respectively. Utilization of solar energy (UV-Vis) and a coupling of novel semiconductor oxide nanoparticles have been recently demonstrated with enhancement in photo-oxidation and/or photo-reduction processes for the water/air detoxification and sustainable liquid fuel production respectively. Magnetic nanoparticles such as ZnFe{sub 2}O{sub 4} have been synthesized and optimized for biomedical applications such as targeted drug delivery and tumor diagnostic sensing (MRI)« less

Nanomaterial-Based Electrochemical Immunosensors for Clinically Significant Biomarkers

PubMed Central

Ronkainen, Niina J.; Okon, Stanley L.

2014-01-01

Nanotechnology has played a crucial role in the development of biosensors over the past decade. The development, testing, optimization, and validation of new biosensors has become a highly interdisciplinary effort involving experts in chemistry, biology, physics, engineering, and medicine. The sensitivity, the specificity and the reproducibility of biosensors have improved tremendously as a result of incorporating nanomaterials in their design. In general, nanomaterials-based electrochemical immunosensors amplify the sensitivity by facilitating greater loading of the larger sensing surface with biorecognition molecules as well as improving the electrochemical properties of the transducer. The most common types of nanomaterials and their properties will be described. In addition, the utilization of nanomaterials in immunosensors for biomarker detection will be discussed since these biosensors have enormous potential for a myriad of clinical uses. Electrochemical immunosensors provide a specific and simple analytical alternative as evidenced by their brief analysis times, inexpensive instrumentation, lower assay cost as well as good portability and amenability to miniaturization. The role nanomaterials play in biosensors, their ability to improve detection capabilities in low concentration analytes yielding clinically useful data and their impact on other biosensor performance properties will be discussed. Finally, the most common types of electroanalytical detection methods will be briefly touched upon. PMID:28788700

Platinum nanoparticles on gallium nitride surfaces: effect of semiconductor doping on nanoparticle reactivity.

PubMed

Schäfer, Susanne; Wyrzgol, Sonja A; Caterino, Roberta; Jentys, Andreas; Schoell, Sebastian J; Hävecker, Michael; Knop-Gericke, Axel; Lercher, Johannes A; Sharp, Ian D; Stutzmann, Martin

2012-08-01

Platinum nanoparticles supported on n- and p-type gallium nitride (GaN) are investigated as novel hybrid systems for the electronic control of catalytic activity via electronic interactions with the semiconductor support. In situ oxidation and reduction were studied with high pressure photoemission spectroscopy. The experiments revealed that the underlying wide-band-gap semiconductor has a large influence on the chemical composition and oxygen affinity of supported nanoparticles under X-ray irradiation. For as-deposited Pt cuboctahedra supported on n-type GaN, a higher fraction of oxidized surface atoms was observed compared to cuboctahedral particles supported on p-type GaN. Under an oxygen atmosphere, immediate oxidation was recorded for nanoparticles on n-type GaN, whereas little oxidation was observed for nanoparticles on p-type GaN. Together, these results indicate that changes in the Pt chemical state under X-ray irradiation depend on the type of GaN doping. The strong interaction between the nanoparticles and the support is consistent with charge transfer of X-ray photogenerated free carriers at the semiconductor-nanoparticle interface and suggests that GaN is a promising wide-band-gap support material for photocatalysis and electronic control of catalysis.

A facile construction of Au nanoparticles stabilized by thermo-responsive polymer-tethered carbon dots for enhanced catalytic performance

NASA Astrophysics Data System (ADS)

Li, Li; Zhang, Tianyi; Lü, Jianhua; Lü, Changli

2018-10-01

Carbon dots (CDs), the youngest member in the carbon nanomaterial family, have drawn considerable attention due to their interesting optical, physicochemical and electronic properties as well as broad promising applications. Here, we developed a facile and effective strategy for the preparation of Au nanoparticles stabilized by thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) functionalized carbon dots (Au@CD@P) under the gentle water media. The as-designed dopamine(DA)-terminated PNIPAM can be easily anchored to CDs via mussel-inspired chemistry route. Both CD@P and CDs could well stabilize the Au nanoparticles with interesting assembled structure. The as-prepared Au@CD and Au@CD@P nanohybrids with good dispersibility and stability exhibited the intriguing catalytic activity for reduction of p-nitrophenol (p-NP). Especially, Au@CD@P as catalyst also played a switching role in regulating the catalytic rate by temperature. In addition, Au@CD@P exhibited excellent recyclability which may have potential in green chemical industry for developing high-activity catalysts and easy production methods.

Regulating the electrical behaviors of 2D inorganic nanomaterials for energy applications.

PubMed

Feng, Feng; Wu, Junchi; Wu, Changzheng; Xie, Yi

2015-02-11

Recent years have witnessed great developments in inorganic 2D nanomaterials for their unique dimensional confinement and diverse electronic energy bands. Precisely regulating their intrinsic electrical behaviors would bring superior electrical conductivity, rendering 2D nanomaterials ideal candidates for active materials in electrochemical applications when combined with the excellent reaction activity from the inorganic lattice. This Concept focuses on highly conducting inorganic 2D nanomaterials, including intrinsic metallic 2D nanomaterials and artificial highly conductive 2D nanomaterials. The intrinsic metallicity of 2D nanomaterials is derived from their closely packed atomic structures that ensure maximum overlapping of electron orbitals, while artificial highly conductive 2D nanomaterials could be achieved by designed methodologies of surface modification, intralayer ion doping, and lattice strain, in which atomic-scale structural modulation plays a vital role in realizing conducting behaviors. Benefiting from fast electron transfer, high reaction activity, as well as large surface areas arising from the 2D inorganic lattice, highly conducting 2D nanomaterials open up prospects for enhancing performance in electrochemical catalysis and electrochemical capacitors. Conductive 2D inorganic nanomaterials promise higher efficiency for electrochemical applications of energy conversion and storage. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Optical and Electronic NO(x) Sensors for Applications in Mechatronics.

PubMed

Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A; Wolter, Scott D; Brown, April; Ricco, Mario

2009-01-01

Current production and emerging NO(x) sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NO(x) show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NO(x) in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NO(x) sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling.

Nanomaterials in consumer's goods: the problems of risk assessment

NASA Astrophysics Data System (ADS)

Gmoshinski, I. V.; Khotimchenko, S. A.

2015-11-01

Nanotechnology and engineered nanomaterials are currently used in wide variety of cosmetic products, while their use in food industry, packaging materials, household chemicals etc. still includes a limited number of items and does not show a significant upward trend. However, the problem of priority nanomaterials associated risks is relevant due to their high production volumes and an constantly growing burden on the environment and population. In accordance with the frequency of use in mass-produced consumer goods, leading priority nanomaterials are silver nanoparticles (NPs) and (by a wide margin) NPs of gold, platinum, and titanium dioxide. Frequency of nanosized silica introduction into food products as a food additive, at the moment, seems to be underestimated, since the use of this nanomaterial is not declared by manufacturers of products and objective control of its content is difficult. Analysis of literature data on toxicological properties of nanomaterials shows that currently accumulated amount of information is sufficient to establish the safe doses of nanosized silver, gold and titanium dioxide. Data have been provided in a series of studies concerning the effect of oral intake of nanosized silica on the condition of laboratory animals, including on the performance of the immune system. The article examines the existing approaches to the assessment of population exposure to priority nanomaterials, characteristics of existing problems and risk management.

Anisotropic nanomaterials: structure, growth, assembly, and functions

PubMed Central

Sajanlal, Panikkanvalappil R.; Sreeprasad, Theruvakkattil S.; Samal, Akshaya K.; Pradeep, Thalappil

2011-01-01

Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications. PMID:22110867

Nanomaterials for Craniofacial and Dental Tissue Engineering.

PubMed

Li, G; Zhou, T; Lin, S; Shi, S; Lin, Y

2017-07-01

Tissue engineering shows great potential as a future treatment for the craniofacial and dental defects caused by trauma, tumor, and other diseases. Due to the biomimetic features and excellent physiochemical properties, nanomaterials are of vital importance in promoting cell growth and stimulating tissue regeneration in tissue engineering. For craniofacial and dental tissue engineering, the frequently used nanomaterials include nanoparticles, nanofibers, nanotubes, and nanosheets. Nanofibers are attractive for cell invasion and proliferation because of their resemblance to extracellular matrix and the presence of large pores, and they have been used as scaffolds in bone, cartilage, and tooth regeneration. Nanotubes and nanoparticles improve the mechanical and chemical properties of scaffold, increase cell attachment and migration, and facilitate tissue regeneration. In addition, nanofibers and nanoparticles are also used as a delivery system to carry the bioactive agent in bone and tooth regeneration, have better control of the release speed of agent upon degradation of the matrix, and promote tissue regeneration. Although applications of nanomaterials in tissue engineering remain in their infancy with numerous challenges to face, the current results indicate that nanomaterials have massive potential in craniofacial and dental tissue engineering.

Defect-Rich Dopant-Free ZrO2 Nanostructures with Superior Dilute Ferromagnetic Semiconductor Properties.

PubMed

Rahman, Md Anisur; Rout, S; Thomas, Joseph P; McGillivray, Donald; Leung, Kam Tong

2016-09-14

Control of the spin degree of freedom of an electron has brought about a new era in spin-based applications, particularly spin-based electronics, with the potential to outperform the traditional charge-based semiconductor technology for data storage and information processing. However, the realization of functional spin-based devices for information processing remains elusive due to several fundamental challenges such as the low Curie temperature of group III-V and II-VI semiconductors (<200 K), and the low spin-injection efficiencies of existing III-V, II-VI, and transparent conductive oxide semiconductors in a multilayer device structure, which are caused by precipitation and migration of dopants from the host layer to the adjacent layers. Here, we use catalyst-assisted pulsed laser deposition to grow, for the first time, oxygen vacancy defect-rich, dopant-free ZrO2 nanostructures with high TC (700 K) and high magnetization (5.9 emu/g). The observed magnetization is significantly greater than both doped and defect-rich transparent conductive oxide nanomaterials reported to date. We also provide the first experimental evidence that it is the amounts and types of oxygen vacancy defects in, and not the phase of ZrO2 that control the ferromagnetic order in undoped ZrO2 nanostructures. To explain the origin of ferromagnetism in these ZrO2 nanostructures, we hypothesize a new defect-induced bound polaron model, which is generally applicable to other defect-rich, dopant-free transparent conductive oxide nanostructures. These results provide new insights into magnetic ordering in undoped dilute ferromagnetic semiconductor oxides and contribute to the design of exotic magnetic and novel multifunctional materials.

Versatile in situ gas analysis apparatus for nanomaterials reactors.

PubMed

Meysami, Seyyed Shayan; Snoek, Lavina C; Grobert, Nicole

2014-09-02

We report a newly developed technique for the in situ real-time gas analysis of reactors commonly used for the production of nanomaterials, by showing case-study results obtained using a dedicated apparatus for measuring the gas composition in reactors operating at high temperature (<1000 °C). The in situ gas-cooled sampling probe mapped the chemistry inside the high-temperature reactor, while suppressing the thermal decomposition of the analytes. It thus allows a more accurate study of the mechanism of progressive thermocatalytic cracking of precursors compared to previously reported conventional residual gas analyses of the reactor exhaust gas and hence paves the way for the controlled production of novel nanomaterials with tailored properties. Our studies demonstrate that the composition of the precursors dynamically changes as they travel inside of the reactor, causing a nonuniform growth of nanomaterials. Moreover, mapping of the nanomaterials reactor using quantitative gas analysis revealed the actual contribution of thermocatalytic cracking and a quantification of individual precursor fragments. This information is particularly important for quality control of the produced nanomaterials and for the recycling of exhaust residues, ultimately leading toward a more cost-effective continuous production of nanomaterials in large quantities. Our case study of multiwall carbon nanotube synthesis was conducted using the probe in conjunction with chemical vapor deposition (CVD) techniques. Given the similarities of this particular CVD setup to other CVD reactors and high-temperature setups generally used for nanomaterials synthesis, the concept and methodology of in situ gas analysis presented here does also apply to other systems, making it a versatile and widely applicable method across a wide range of materials/manufacturing methods, catalysis, as well as reactor design and engineering.

Semiconductor photoelectrochemistry

NASA Technical Reports Server (NTRS)

Buoncristiani, A. M.; Byvik, C. E.

1983-01-01

Semiconductor photoelectrochemical reactions are investigated. A model of the charge transport processes in the semiconductor, based on semiconductor device theory, is presented. It incorporates the nonlinear processes characterizing the diffusion and reaction of charge carriers in the semiconductor. The model is used to study conditions limiting useful energy conversion, specifically the saturation of current flow due to high light intensity. Numerical results describing charge distributions in the semiconductor and its effects on the electrolyte are obtained. Experimental results include: an estimate rate at which a semiconductor photoelectrode is capable of converting electromagnetic energy into chemical energy; the effect of cell temperature on the efficiency; a method for determining the point of zero zeta potential for macroscopic semiconductor samples; a technique using platinized titanium dioxide powders and ultraviolet radiation to produce chlorine, bromine, and iodine from solutions containing their respective ions; the photoelectrochemical properties of a class of layered compounds called transition metal thiophosphates; and a technique used to produce high conversion efficiency from laser radiation to chemical energy.

Analyzing the application of silicon-silver-2D nanomaterial-Al2O3 heterojunction in plasmonic sensor and its performance evaluation

NASA Astrophysics Data System (ADS)

Sharma, Anuj K.

2018-03-01

A semiconductor-metal-dielectric heterojunction system, generally useful in enhancing the efficiency of solar cells, is explored to design a high performance optical sensor based on surface plasmon resonance in near infrared (NIR). Silicon is considered as light coupling material and different 2D nanomaterials such as graphene, MoS2, and MoSe2 are explored to enhance the sensor's performance in terms of its figure of merit (FOM). An Al2O3 interlayer with a few nanometers of thickness is introduced, which acts as a critical component to significantly enhance the sensor's FOM. It is observed that an Al2O3 interlayer of around 9 nm thickness is able to many-fold upturn the sensor's FOM. As another important finding, silver layer thickness of around 60 nm is found to be highly useful to achieve high values of FOM. It is established through results that operating at longer NIR wavelength leads to greater FOM for any choice of 2D nanomaterial and any thickness of Al2O3 interlayer. Proposed sensor provides significantly greater FOM than previous works on SPR sensors.

Microreactor-Assisted Nanomaterial Deposition for Photovoltaic Thin-Film Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-03-01

This factsheet describes a research project whose goal is to develop and demonstrate a scalable microreactor-assisted nanomaterial deposition pilot platform for the production, purification, functionalization, and solution deposition of nanomaterials for PV applications.

Development of a Nanomaterials One-Week Intersession Course

ERIC Educational Resources Information Center

Walters, Keith A.; Bullen, Heather A.

2008-01-01

A novel one-week intersession lecture-lab hybrid course on nanomaterials is presented. The course provided a combination of background theory and hands-on laboratory experiments to educate students about nanomaterials and nanotechnology. The design of the course, subject matter, and laboratory experiments are discussed. Topics and level were…

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.

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.

Nanomaterials: a challenge for toxicological risk assessment?

PubMed

Haase, Andrea; Tentschert, Jutta; Luch, Andreas

2012-01-01

Nanotechnology has emerged as one of the central technologies in the twenty-first century. This judgment becomes apparent by considering the increasing numbers of people employed in this area; the numbers of patents, of scientific publications, of products on the market; and the amounts of money invested in R&D. Prospects originating from different fields of nanoapplication seem unlimited. However, nanotechnology certainly will not be able to meet all of the ambitious expectations communicated, yet has high potential to heavily affect our daily life in the years to come. This might occur in particular in the field of consumer products, for example, by introducing nanomaterials in cosmetics, textiles, or food contact materials. Another promising area is the application of nanotechnology in medicine fueling hopes to significantly improve diagnosis and treatment of all kinds of diseases. In addition, novel technologies applying nanomaterials are expected to be instrumental in waste remediation and in the production of efficient energy storage devices and thus may help to overcome world's energy problems or to revolutionize computer and data storage technologies. In this chapter, we will focus on nanomaterials. After a brief historic and general overview, current proposals of how to define nanomaterials will be summarized. Due to general limitations, there is still no single, internationally accepted definition of the term "nanomaterial." After elaborating on the status quo and the scope of nanoanalytics and its shortcomings, the current thinking about possible hazards resulting from nanoparticulate exposures, there will be an emphasis on the requirements to be fulfilled for appropriate health risk assessment and regulation of nanomaterials. With regard to reliable risk assessments, until now there is still the remaining issue to be resolved of whether or not specific challenges and unique features exist on the nanoscale that have to be tackled and distinctively

Health and safety implications of occupational exposure to engineered nanomaterials.

PubMed

Stebounova, Larissa V; Morgan, Hallie; Grassian, Vicki H; Brenner, Sara

2012-01-01

The rapid growth and commercialization of nanotechnology are currently outpacing health and safety recommendations for engineered nanomaterials. As the production and use of nanomaterials increase, so does the possibility that there will be exposure of workers and the public to these materials. This review provides a summary of current research and regulatory efforts related to occupational exposure and medical surveillance for the nanotechnology workforce, focusing on the most prevalent industrial nanomaterials currently moving through the research, development, and manufacturing pipelines. Their applications and usage precedes a discussion of occupational health and safety efforts, including exposure assessment, occupational health surveillance, and regulatory considerations for these nanomaterials. Copyright © 2011 Wiley Periodicals, Inc.

Assessing the Implications of Modified Nanomaterials in Bioassay Testing

EPA Science Inventory

As nanotechnology advances to product development, filling environmental health and safety knowledge gaps is critical. Nanotoxicology is over-generalized, provided the permutations of nanomaterial variants created by the classes of nanomaterials (carbonaceous, metals, quantum dot...

Engineering of Multifunctional Nanomaterials for Cancer Theranostics

NASA Astrophysics Data System (ADS)

Goel, Shreya

Development of novel imaging probes for cancer diagnosis is critical for early disease detection and management. The past two decades have witnessed a surge in the development and evolution of radiolabeled nanoparticles as a new frontier in personalized cancer nanomedicine. The dynamic synergism of positron emission tomography (PET) and nanotechnology combines the sensitivity and quantitative nature of PET with the multifunctionality and tunability of nanomaterials, which can help overcome certain key challenges in the field. Silica, "generally recognized as safe" (GRAS) by the Food and Drug Administration (FDA) of the United States, has emerged as one of the leading nanomaterials employed for molecular imaging and therapy of a wide variety of diseases, including cancer. However in vivo biodistribution and active targeting of silica-based nanomaterials has remained a relatively under explored area, based mainly on semi-quantitative techniques such as fluorescence imaging. In this dissertation, I explore the concept of radiolabeled silica nanoparticles for vasculature-targeted imaging of different tumor types. Both chelator-based and chelator-free radiolabeling techniques were employed for accurate and quantitative analysis of the in vivo pharmacokinetics of radiolabeled silica nanomaterials. (Chapters 2 and 3) The large surface area, ease of tunability and facile silica chemistry were employed to create multifunctional silica-based materials to simultaneously seek-and-treat cancers, by incorporating multiple components into a single nanoplatform. Photodynamic agent, porphyrin was loaded into the central cavity of hollow mesoporous silica nanoparticles, and the shell was decorated with photothermal nanoparticles, CuS, yielding a multimodal theranostic nanoplatform which could synergistically annihilate the tumor without relapse. (Chapter 4). A major hurdle in the successful clinical translation of nanomaterials is their rapid sequestration by the organs of the

Toward designing semiconductor-semiconductor heterojunctions for photocatalytic applications

NASA Astrophysics Data System (ADS)

Zhang, Liping; Jaroniec, Mietek

2018-02-01

Semiconductor photocatalysts show a great potential for environmental and energy-related applications, however one of the major disadvantages is their relatively low photocatalytic performance due to the recombination of electron-hole pairs. Therefore, intensive research is being conducted toward design of heterojunctions, which have been shown to be effective for improving the charge-transfer properties and efficiency of photocatalysts. According to the type of band alignment and direction of internal electric field, heterojunctions are categorized into five different types, each of which is associated with its own charge transfer characteristics. Since the design of heterojunctions requires the knowledge of band edge positions of component semiconductors, the commonly used techniques for the assessment of band edge positions are reviewed. Among them the electronegativity-based calculation method is applied for a large number of popular visible-light-active semiconductors, including some widely investigated bismuth-containing semiconductors. On basis of the calculated band edge positions and the type of component semiconductors reported, heterojunctions composed of the selected bismuth-containing semiconductors are proposed. Finally, the most popular synthetic techniques for the fabrication of heterojunctions are briefly discussed.

How should the completeness and quality of curated nanomaterial data be evaluated?

NASA Astrophysics Data System (ADS)

Marchese Robinson, Richard L.; Lynch, Iseult; Peijnenburg, Willie; Rumble, John; Klaessig, Fred; Marquardt, Clarissa; Rauscher, Hubert; Puzyn, Tomasz; Purian, Ronit; Åberg, Christoffer; Karcher, Sandra; Vriens, Hanne; Hoet, Peter; Hoover, Mark D.; Hendren, Christine Ogilvie; Harper, Stacey L.

2016-05-01

Nanotechnology is of increasing significance. Curation of nanomaterial data into electronic databases offers opportunities to better understand and predict nanomaterials' behaviour. This supports innovation in, and regulation of, nanotechnology. It is commonly understood that curated data need to be sufficiently complete and of sufficient quality to serve their intended purpose. However, assessing data completeness and quality is non-trivial in general and is arguably especially difficult in the nanoscience area, given its highly multidisciplinary nature. The current article, part of the Nanomaterial Data Curation Initiative series, addresses how to assess the completeness and quality of (curated) nanomaterial data. In order to address this key challenge, a variety of related issues are discussed: the meaning and importance of data completeness and quality, existing approaches to their assessment and the key challenges associated with evaluating the completeness and quality of curated nanomaterial data. Considerations which are specific to the nanoscience area and lessons which can be learned from other relevant scientific disciplines are considered. Hence, the scope of this discussion ranges from physicochemical characterisation requirements for nanomaterials and interference of nanomaterials with nanotoxicology assays to broader issues such as minimum information checklists, toxicology data quality schemes and computational approaches that facilitate evaluation of the completeness and quality of (curated) data. This discussion is informed by a literature review and a survey of key nanomaterial data curation stakeholders. Finally, drawing upon this discussion, recommendations are presented concerning the central question: how should the completeness and quality of curated nanomaterial data be evaluated?Nanotechnology is of increasing significance. Curation of nanomaterial data into electronic databases offers opportunities to better understand and predict

Semiconductor sensors

NASA Technical Reports Server (NTRS)

Gatos, Harry C. (Inventor); Lagowski, Jacek (Inventor)

1977-01-01

A semiconductor sensor adapted to detect with a high degree of sensitivity small magnitudes of a mechanical force, presence of traces of a gas or light. The sensor includes a high energy gap (i.e., .about. 1.0 electron volts) semiconductor wafer. Mechanical force is measured by employing a non-centrosymmetric material for the semiconductor. Distortion of the semiconductor by the force creates a contact potential difference (cpd) at the semiconductor surface, and this cpd is determined to give a measure of the force. When such a semiconductor is subjected to illumination with an energy less than the energy gap of the semiconductors, such illumination also creates a cpd at the surface. Detection of this cpd is employed to sense the illumination itself or, in a variation of the system, to detect a gas. When either a gas or light is to be detected and a crystal of a non-centrosymmetric material is employed, the presence of gas or light, in appropriate circumstances, results in a strain within the crystal which distorts the same and the distortion provides a mechanism for qualitative and quantitative evaluation of the gas or the light, as the case may be.

Understanding the biological and environmental implications of nanomaterials

NASA Astrophysics Data System (ADS)

Lin, Sijie

The last two decades have witnessed the discovery, development, and large-scale manufacturing of novel nanomaterials. While nanomaterials bring in exciting and extraordinary properties in all areas of materials, electronics, mechanics, and medicine, they also could generate potential adverse effects in biological systems and in the environment. The currently limited application of nanomaterials in biological and ecological systems results from the insufficient and often controversial data on describing the complex behaviors of nanomaterials in living systems. The purpose of this dissertation intends to fill such a knowledge void with methodologies from the disciplines of biophysics, biology, and materials science and engineering. Chapter 1 of this dissertation provides a comprehensive review on the structures and properties of carbon nanomaterials (CBNMs), metal oxides, and quantum dots (QDs). This chapter also details the state-of-the-art on the biological applications, ecological applications, and toxicity of nanomaterials. With Chapter 1 serving as a background, Chapters 2-5 present my PhD research, an inquiry on the fate of nanomaterials in biological and ecological systems, on the whole organism and cellular levels. Specifically, CBNMs are introduced to rice plant seedlings and the uptake, translocation and generational transfer of fullerene C70 in the plant compartments are imaged and characterized. The interactions between CBNMs and rice plants on the whole organism level are initiated by the binding between CBNMs and natural organic matter (NOM), driven by the transpiration of water from the roots to the leaves of the plants and mediated by both the physiochemical properties of the CBNMs and plant physiology. In Chapter 3, semiconducting nanocrystals quantum dots (QDs) are introduced to green algae Chlamydomonas to probe the interactions of nanomaterials with ecological systems on the cellular level. The adsorption of QDs onto the algal cell wall is

Fabrication of functional nanomaterials using flame assisted spray pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purwanto, Agus, E-mail: aguspur@uns.ac.id

2014-02-24

Flame assisted spray pyrolysis (FASP) is a class of synthesis method for nanomaterials fabrication. The ability to control nanomaterials characteristics and easy to be-scaled up are the main features of FASP. The crystallinity and particles size of the prepared nanomaterials can be easily controlled by variation of fuel flow rate. The precursor concentration, carrier gas flow rate, and carrier gas can be also used to control the prepared nanomaterials. Energy related nanomaterials preparation uses as the example case in FASP application. These material are yttrium aluminum garnet (YAG:Ce) and tungsten oxide (WO{sub 3}). It needs strategies to produce these materialsmore » into nano-sized order. YAG:Ce nanoparticles only can be synthesized by FASP using the urea addition. The decomposition of urea under high temperature of flame promotes the breakage of YAG:Ce particles into nanoparticles. In the preparation of WO{sub 3}, the high temperature flame can be used to gasify WO{sub 3} solid material. As a result, WO{sub 3} nanoparticles can be prepared easily. Generally, to produce nanoparticles via FASP method, the boiling point of the material is important to determine the strategy which will be used.« less

Electrochemical and optical biosensors based on nanomaterials and nanostructures: a review.

PubMed

Li, Ming; Li, Rui; Li, Chang Ming; Wu, Nianqiang

2011-06-01

Nanomaterials and nanostructures exhibit unique size-tunable and shape-dependent physicochemical properties that are different from those of bulk materials. Advances of nanomaterials and nanostructures open a new door to develop various novel biosensors. The present work has reviewed the recent progress in electrochemical, surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS) and fluorescent biosensors based on nanomaterials and nanostructures. An emphasis is put on the research that demonstrates how the performance of biosensors such as the limit of detection, sensitivity and selectivity is improved by the use of nanomaterials and nanostructures.

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.

Smart nanomaterials for biomedics.

PubMed

Choi, Soonmo; Tripathi, Anuj; Singh, Deepti

2014-10-01

Nanotechnology has become important in various disciplines of technology and science. It has proven to be a potential candidate for various applications ranging from biosensors to the delivery of genes and therapeutic agents to tissue engineering. Scaffolds for every application can be tailor made to have the appropriate physicochemical properties that will influence the in vivo system in the desired way. For highly sensitive and precise detection of specific signals or pathogenic markers, or for sensing the levels of particular analytes, fabricating target-specific nanomaterials can be very useful. Multi-functional nano-devices can be fabricated using different approaches to achieve multi-directional patterning in a scaffold with the ability to alter topographical cues at scale of less than or equal to 100 nm. Smart nanomaterials are made to understand the surrounding environment and act accordingly by either protecting the drug in hostile conditions or releasing the "payload" at the intended intracellular target site. All of this is achieved by exploiting polymers for their functional groups or incorporating conducting materials into a natural biopolymer to obtain a "smart material" that can be used for detection of circulating tumor cells, detection of differences in the body analytes, or repair of damaged tissue by acting as a cell culture scaffold. Nanotechnology has changed the nature of diagnosis and treatment in the biomedical field, and this review aims to bring together the most recent advances in smart nanomaterials.

Application of nanomaterials in the bioanalytical detection of disease-related genes.

PubMed

Zhu, Xiaoqian; Li, Jiao; He, Hanping; Huang, Min; Zhang, Xiuhua; Wang, Shengfu

2015-12-15

In the diagnosis of genetic diseases and disorders, nanomaterials-based gene detection systems have significant advantages over conventional diagnostic systems in terms of simplicity, sensitivity, specificity, and portability. In this review, we describe the application of nanomaterials for disease-related genes detection in different methods excluding PCR-related method, such as colorimetry, fluorescence-based methods, electrochemistry, microarray methods, surface-enhanced Raman spectroscopy (SERS), quartz crystal microbalance (QCM) methods, and dynamic light scattering (DLS). The most commonly used nanomaterials are gold, silver, carbon and semiconducting nanoparticles. Various nanomaterials-based gene detection methods are introduced, their respective advantages are discussed, and selected examples are provided to illustrate the properties of these nanomaterials and their emerging applications for the detection of specific nucleic acid sequences. Copyright © 2015. Published by Elsevier B.V.

Copper-based nanomaterials for environmental decontamination - An overview on technical and toxicological aspects.

PubMed

Khalaj, Mohammadreza; Kamali, Mohammadreza; Khodaparast, Zahra; Jahanshahi, Akram

2018-02-01

Synthesis of the various types of engineered nanomaterials has gained a huge attention in recent years for various applications. Copper based nanomaterials are a branch of this category seem to be able to provide an efficient and cost-effective way for the treatment of the persistent effluents. The present work aimed to study the various parameters may involve in the overall performance of the copper based nanomaterials for environmental clean-up purposes. To this end, the related characteristics of copper based nanomaterials and their effects on the nanomaterials reactivity and the environmental and operating parameters have been critically reviewed. Toxicological study of the copper based nanomaterials has been also considered as a factor with high importance for the selection of a typical nanomaterial with optimum performance and minimum environmental and health subsequent effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of risk-based nanomaterial groups for occupational exposure control

NASA Astrophysics Data System (ADS)

Kuempel, E. D.; Castranova, V.; Geraci, C. L.; Schulte, P. A.

2012-09-01

Given the almost limitless variety of nanomaterials, it will be virtually impossible to assess the possible occupational health hazard of each nanomaterial individually. The development of science-based hazard and risk categories for nanomaterials is needed for decision-making about exposure control practices in the workplace. A possible strategy would be to select representative (benchmark) materials from various mode of action (MOA) classes, evaluate the hazard and develop risk estimates, and then apply a systematic comparison of new nanomaterials with the benchmark materials in the same MOA class. Poorly soluble particles are used here as an example to illustrate quantitative risk assessment methods for possible benchmark particles and occupational exposure control groups, given mode of action and relative toxicity. Linking such benchmark particles to specific exposure control bands would facilitate the translation of health hazard and quantitative risk information to the development of effective exposure control practices in the workplace. A key challenge is obtaining sufficient dose-response data, based on standard testing, to systematically evaluate the nanomaterials' physical-chemical factors influencing their biological activity. Categorization processes involve both science-based analyses and default assumptions in the absence of substance-specific information. Utilizing data and information from related materials may facilitate initial determinations of exposure control systems for nanomaterials.

Production of Two-Dimensional Nanomaterials via Liquid-Based Direct Exfoliation.

PubMed

Niu, Liyong; Coleman, Jonathan N; Zhang, Hua; Shin, Hyeonsuk; Chhowalla, Manish; Zheng, Zijian

2016-01-20

Tremendous efforts have been devoted to the synthesis and application of two-dimensional (2D) nanomaterials due to their extraordinary and unique properties in electronics, photonics, catalysis, etc., upon exfoliation from their bulk counterparts. One of the greatest challenges that scientists are confronted with is how to produce large quantities of 2D nanomaterials of high quality in a commercially viable way. This review summarizes the state-of-the-art of the production of 2D nanomaterials using liquid-based direct exfoliation (LBE), a very promising and highly scalable wet approach for synthesizing high quality 2D nanomaterials in mild conditions. LBE is a collection of methods that directly exfoliates bulk layered materials into thin flakes of 2D nanomaterials in liquid media without any, or with a minimum degree of, chemical reactions, so as to maintain the high crystallinity of 2D nanomaterials. Different synthetic methods are categorized in the following, in which material characteristics including dispersion concentration, flake thickness, flake size and some applications are discussed in detail. At the end, we provide an overview of the advantages and disadvantages of such synthetic methods of LBE and propose future perspectives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distinguishing nanomaterial particles from background airborne particulate matter for quantitative exposure assessment

NASA Astrophysics Data System (ADS)

Ono-Ogasawara, Mariko; Serita, Fumio; Takaya, Mitsutoshi

2009-10-01

As the production of engineered nanomaterials quantitatively expands, the chance that workers involved in the manufacturing process will be exposed to nanoparticles also increases. A risk management system is needed for workplaces in the nanomaterial industry based on the precautionary principle. One of the problems in the risk management system is difficulty of exposure assessment. In this article, examples of exposure assessment in nanomaterial industries are reviewed with a focus on distinguishing engineered nanomaterial particles from background nanoparticles in workplace atmosphere. An approach by JNIOSH (Japan National Institute of Occupational Safety and Health) to quantitatively measure exposure to carbonaceous nanomaterials is also introduced. In addition to real-time measurements and qualitative analysis by electron microscopy, quantitative chemical analysis is necessary for quantitatively assessing exposure to nanomaterials. Chemical analysis is suitable for quantitative exposure measurement especially at facilities with high levels of background NPs.

In Vitro Cytotoxicity of Silver Nanomaterials in Murine Macrophages

EPA Science Inventory

Silver nanomaterials are increasingly used as antimicrobial agents in a variety of products. Although there is considerable potential for human exposure to these nanomaterials, little is known about the health risks associated with their use. Macrophages are prominent immune cell...

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.

Observations on the interaction of nanomaterials with bacteria

NASA Astrophysics Data System (ADS)

Raja, P. M.; Ajayan, P. M.; Nalamasu, O.; Sharma, A.

2006-05-01

Large scale commercial manufacturing of nanomaterials raises the important issue of their environmental fate. With increased production (estimated to be in million gallon range) the nanomaterial interactions with environmental microbial ecology would be significant. However, there are scant studies that have addressed this concern. It is therefore essential to experimentally determine some fundamental parameters to ascertain any environmental stresses related to microbiological interactions of nanomaterials. There are concerns that such an interaction may be similar to the biogeochemical interactions of asbestos fibers, which continues to be an alarming environmental issue. Carbon nanotubes (CNTs) are newly emerging nanomaterials, with a wide range of potential electronic and medical applications. Though CNTs are dimensionally similar to the mineral fibers, they differ morphologically, and can possess different surface chemistries, capable of complex and varied biological interactions within the environment. In this study, we present experimental data that show discernible effects on microbial morphology, biofilm formation, substrate consumption rates and growth of Escherichia coli in the presence of carbon nanotubes with the aim of developing a fundamental understanding of the environmental implications of CNT-microbial interactions.

Nanomaterial-enabled Rapid Detection of Water Contaminants.

PubMed

Mao, Shun; Chang, Jingbo; Zhou, Guihua; Chen, Junhong

2015-10-28

Water contaminants, e.g., inorganic chemicals and microorganisms, are critical metrics for water quality monitoring and have significant impacts on human health and plants/organisms living in water. The scope and focus of this review is nanomaterial-based optical, electronic, and electrochemical sensors for rapid detection of water contaminants, e.g., heavy metals, anions, and bacteria. These contaminants are commonly found in different water systems. The importance of water quality monitoring and control demands significant advancement in the detection of contaminants in water because current sensing technologies for water contaminants have limitations. The advantages of nanomaterial-based sensing technologies are highlighted and recent progress on nanomaterial-based sensors for rapid water contaminant detection is discussed. An outlook for future research into this rapidly growing field is also provided. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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/...

Band structure engineering strategies of metal oxide semiconductor nanowires and related nanostructures: A review

NASA Astrophysics Data System (ADS)

Piyadasa, Adimali; Wang, Sibo; Gao, Pu-Xian

2017-07-01

The electronic band structure of a solid state semiconductor determines many of its physical and chemical characteristics such as electrical, optical, physicochemical, and catalytic activity. Alteration or modification of the band structure could lead to significant changes in these physical and chemical characteristics, therefore we introduce new mechanisms of creating novel solid state materials with interesting properties. Over the past three decades, research on band structure engineering has allowed development of various methods to modify the band structure of engineered materials. Compared to bulk counterparts, nanostructures generally exhibit higher band structure modulation capabilities due to the quantum confinement effect, prominent surface effect, and higher strain limit. In this review we will discuss various band structure engineering strategies in semiconductor nanowires and other related nanostructures, mostly focusing on metal oxide systems. Several important strategies of band structure modulation are discussed in detail, such as doping, alloying, straining, interface and core-shell nanostructuring.

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 ...

Final Report: "Energetics of Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 compositionmore » 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.« less

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

Octanol-water distribution of engineered nanomaterials.

PubMed

Hristovski, Kiril D; Westerhoff, Paul K; Posner, Jonathan D

2011-01-01

The goal of this study was to examine the effects of pH and ionic strength on octanol-water distribution of five model engineered nanomaterials. Distribution experiments resulted in a spectrum of three broadly classified scenarios: distribution in the aqueous phase, distribution in the octanol, and distribution into the octanol-water interface. Two distribution coefficients were derived to describe the distribution of nanoparticles among octanol, water and their interface. The results show that particle surface charge, surface functionalization, and composition, as well as the solvent ionic strength and presence of natural organic matter, dramatically impact this distribution. Distributions of nanoparticles into the interface were significant for nanomaterials that exhibit low surface charge in natural pH ranges. Increased ionic strengths also contributed to increased distributions of nanoparticle into the interface. Similarly to the octanol-water distribution coefficients, which represent a starting point in predicting the environmental fate, bioavailability and transport of organic pollutants, distribution coefficients such as the ones described in this study could help to easily predict the fate, bioavailability, and transport of engineered nanomaterials in the environment.

Application of nanomaterials in solar thermal energy storage

NASA Astrophysics Data System (ADS)

Shamshirgaran, Seyed Reza; Khalaji Assadi, Morteza; Viswanatha Sharma, Korada

2018-06-01

Solar thermal conversion technology harvests the sun's energy, rather than fossil fuels, to generate low-cost, low/zero-emission energy in the form of heating, cooling or electrical form for residential, commercial, and industrial sectors. The advent of nanofluids and nanocomposites or phase change materials, is a new field of study which is adapted to enhance the efficiency of solar collectors. The concepts of thermal energy storage technologies are investigated and the role of nanomaterials in energy conversion is discussed. This review revealed that although the exploitation of nanomaterials will boost the performance of solar collectors almost in all cases, this would be accompanied by certain challenges such as production cost, instability, agglomeration and erosion. Earlier studies have dealt with the enhancement of thermal conductivity and heat capacity; however, less attention has been given to the facing challenges. Moreover, no exact criteria can be found for the selection of appropriate nanomaterials and their properties for a specific application. In most research studies, the nanoparticles' material and properties have not been selected based on estimated values so that all the aspects of desired application could be considered simultaneously. The wide spread use of nanomaterials can lead to cost effective solutions as well. Therefore, it seems there should be a sense of techno-economic optimization in exploiting nanomaterials for solar thermal energy storage applications. The optimization should cover the key parameters, particularly nanoparticle type, size, loading and shape which depends on the sort of application and also dispersion technology.

Application of nanomaterials in solar thermal energy storage

NASA Astrophysics Data System (ADS)

Shamshirgaran, Seyed Reza; Khalaji Assadi, Morteza; Viswanatha Sharma, Korada

2017-12-01

Solar thermal conversion technology harvests the sun's energy, rather than fossil fuels, to generate low-cost, low/zero-emission energy in the form of heating, cooling or electrical form for residential, commercial, and industrial sectors. The advent of nanofluids and nanocomposites or phase change materials, is a new field of study which is adapted to enhance the efficiency of solar collectors. The concepts of thermal energy storage technologies are investigated and the role of nanomaterials in energy conversion is discussed. This review revealed that although the exploitation of nanomaterials will boost the performance of solar collectors almost in all cases, this would be accompanied by certain challenges such as production cost, instability, agglomeration and erosion. Earlier studies have dealt with the enhancement of thermal conductivity and heat capacity; however, less attention has been given to the facing challenges. Moreover, no exact criteria can be found for the selection of appropriate nanomaterials and their properties for a specific application. In most research studies, the nanoparticles' material and properties have not been selected based on estimated values so that all the aspects of desired application could be considered simultaneously. The wide spread use of nanomaterials can lead to cost effective solutions as well. Therefore, it seems there should be a sense of techno-economic optimization in exploiting nanomaterials for solar thermal energy storage applications. The optimization should cover the key parameters, particularly nanoparticle type, size, loading and shape which depends on the sort of application and also dispersion technology.

Potential space applications of nanomaterials and standartization issues

NASA Astrophysics Data System (ADS)

Voronina, Ekaterina; Novikov, Lev

Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions as well as in the construction of inhabited bases on the Moon. Nanocomposites with nanoclays, carbon nanotubes and various nanoparticles as fillers are one of the most promising materials for space applications. They may be used as light-weighted and strong structural materials as well as functional and smart materials of general and specific applications, e.g. thermal stabilization, radiation shielding, electrostatic charge mitigation, protection of atomic oxygen influence and space debris impact, etc. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. In this presentation, a brief review of existing standards and standards under development in this field is given. Most such standards are related to nanoparticles and nanotube production and characterization, thus the next important step in this activity is the creation of standards on nanomaterial properties and their behavior in different environmental conditions, including extreme environments. The near-Earth’s space is described as an extreme environment for materials due to high vacuum, space radiation, hot and cold plasma, micrometeoroids and space debris, temperature differences, etc. Existing experimental and theoretical data demonstrate that nanomaterials response to various space environment effects may differ substantially from the one of conventional bulk spacecraft materials. Therefore, it is necessary to determine the space environment components, critical for

Recent advances in exploitation of nanomaterial for arsenic removal from water: a review

NASA Astrophysics Data System (ADS)

Wong, WeiWen; Wong, H. Y.; Badruzzaman, A. Borhan M.; Goh, H. H.; Zaman, Mukter

2017-01-01

Recently, increasing research efforts have been made to exploit the enormous potential of nanotechnology and nanomaterial in the application of arsenic removal from water. As a result, there are myriad of types of nanomaterials being developed and studied for their arsenic removal capabilities. Nevertheless, challenges such as having a complete understanding of the material properties and removal mechanism make it difficult for researchers to engineer nanomaterials that are best suited for specific water treatment applications. In this review paper, a comprehensive review will be conducted on several selected categories of nanomaterials that possess promising prospects in arsenic removal application. The synthesis process, material properties, as well as arsenic removal performance and removal mechanisms of each of these nanomaterials will be discussed in detail. Fe-based nanomaterials, particularly iron oxide nanoparticles, have displayed advantages in arsenic removal due to their super-paramagnetic property. On the other hand, TiO2-based nanomaterials are the best candidates as photocatalytic arsenic removal agents, having been reported to have more than 200-fold increase in adsorption capacity under UV light irradiation. Zr-based nanomaterials have among the largest BET active area for adsorption—up to 630 m2 g-1—and it has been reported that amorphous ZrO2 performs better than crystalline ZrO2 nanoparticles, having about 1.77 times higher As(III) adsorption capacity. Although Cu-based nanomaterials are relatively uncommon as nano-adsorbents for arsenic in water, recent studies have demonstrated their potential in arsenic removal. CuO nanoparticles synthesized by Martinson et al were reported to have adsorption capacities up to 22.6 mg g-1 and 26.9 mg g-1 for As(V) and As(III) respectively. Among the nanomaterials that have been reviewed in this study, Mg-based nanomaterials were reported to have the highest maximum adsorption capacities for As(V) and As

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.

A Review of Carbon Nanomaterials' Synthesis via the Chemical Vapor Deposition (CVD) Method.

PubMed

Manawi, Yehia M; Samara, Ayman; Al-Ansari, Tareq; Atieh, Muataz A

2018-05-17

Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD) method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, carbide-derived carbon (CDC), carbon nano-onion (CNO) and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research.

78 FR 36784 - Survey of Nanomaterial Risk Management Practices

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

...-0010, Docket Number NIOSH-265] Survey of Nanomaterial Risk Management Practices AGENCY: National...), Department of Health and Human Services (HHS). ACTION: Proposed NIOSH Survey of Nanomaterial Risk Management... public meeting and opportunity for comment on a proposed NIOSH survey. The primary purpose of the survey...

Gold Nanomaterials in Consumer Cosmetics Nanoproducts: Analyses, Characterization, and Dermal Safety Assessment.

PubMed

Cao, Mingjing; Li, Jiayang; Tang, Jinglong; Chen, Chunying; Zhao, Yuliang

2016-10-01

Establishment of analytical methods of engineered nanomaterials in consumer products for their human and environmental risk assessment becomes urgent for both academic and industrial needs. Owing to the difficulties and challenges around nanomaterials in complex media, proper chemical separation and biological assays of nanomaterials from nanoproducts needs to be firstly developed. Herein, a facile and rapid method to separate and analyze gold nanomaterials in cosmetics is reported. Gold nanomaterials are successfully separated from different facial or eye creams and their physiochemical properties are analyzed by quantitative and qualitative state-of-the art techniques with high sensitivity or high spatial resolution. In turn, a protocol including quantification of gold by inductively coupled plasma mass spectrometry and thorough characterization of morphology, size distribution, and surface property by electron microscopes, atomic force microscope, and X-ray photoelectron spectroscope is developed. Subsequently, the preliminary toxicity assessment indicates that gold nanomaterials in cosmetic creams have no observable toxicity to human keratinocytes even after 24 h exposure up to a concentration of 200 μg mL -1 . The environmental scanning electron microscope reveals that gold nanomaterials are mostly attached on the cell membrane. Thus, the present study provides a full analysis protocol for toxicity assessment of gold nanomaterials in consumer products (cosmetic creams). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal Oxide Nanomaterial QNAR Models: Available Structural Descriptors and Understanding of Toxicity Mechanisms

PubMed Central

Ying, Jiali; Zhang, Ting; Tang, Meng

2015-01-01

Metal oxide nanomaterials are widely used in various areas; however, the divergent published toxicology data makes it difficult to determine whether there is a risk associated with exposure to metal oxide nanomaterials. The application of quantitative structure activity relationship (QSAR) modeling in metal oxide nanomaterials toxicity studies can reduce the need for time-consuming and resource-intensive nanotoxicity tests. The nanostructure and inorganic composition of metal oxide nanomaterials makes this approach different from classical QSAR study; this review lists and classifies some structural descriptors, such as size, cation charge, and band gap energy, in recent metal oxide nanomaterials quantitative nanostructure activity relationship (QNAR) studies and discusses the mechanism of metal oxide nanomaterials toxicity based on these descriptors and traditional nanotoxicity tests. PMID:28347085

ZnO nanomaterials based surface acoustic wave ethanol gas sensor.

PubMed

Wu, Y; Li, X; Liu, J H; He, Y N; Yu, L M; Liu, W H

2012-08-01

ZnO nanomaterials based surface acoustic wave (SAW) gas sensor has been investigated in ethanol environment at room temperature. The ZnO nanomaterials have been prepared through thermal evaporation of high-purity zinc powder. The as-prepared ZnO nanomaterials have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray Diffraction (XRD) techniques. The results indicate that the obtained ZnO nanomaterials, including many types of nanostructures such as nanobelts, nanorods, nanowires as well as nanosheets, are wurtzite with hexagonal structure and well-crystallized. The SAW sensor coated with the nanostructured ZnO materials has been tested in ethanol gas of various concentrations at room temperature. A network analyzer is used to monitor the change of the insertion loss of the SAW sensor when exposed to ethanol gas. The insertion loss of the SAW sensor varies significantly with the change of ethanol concentration. The experimental results manifest that the ZnO nanomaterials based SAW ethanol gas sensor exhibits excellent sensitivity and good short-term reproducibility at room temperature.

Nano-materials for adhesive-free adsorbers for bakable extreme high vacuum cryopump surfaces

DOEpatents

Stutzman, Marcy; Jordan, Kevin; Whitney, Roy R.

2016-10-11

A cryosorber panel having nanomaterials used for the cryosorption material, with nanomaterial either grown directly on the cryopanel or freestanding nanomaterials attached to the cryopanel mechanically without the use of adhesives. Such nanomaterial cryosorber materials can be used in place of conventional charcoals that are attached to cryosorber panels with special low outgassing, low temperature capable adhesives. Carbon nanotubes and other nanomaterials could serve the same purpose as conventional charcoal cryosorbers, providing a large surface area for cryosorption without the need for adhesive since the nanomaterials can be grown directly on a metallic substrate or mechanically attached. The nanomaterials would be capable of being fully baked by heating above 100.degree. C., thereby eliminating water vapor from the system, eliminating adhesives from the system, and allowing a full bake of the system to reduce hydrogen outgassing, with the goal of obtaining extreme high vacuum where the pump can produce pressures below 1.times.10.sup.-12 Torr.

Nanomaterials: certain aspects of application, risk assessment and risk communication.

PubMed

Laux, Peter; Tentschert, Jutta; Riebeling, Christian; Braeuning, Albert; Creutzenberg, Otto; Epp, Astrid; Fessard, Valérie; Haas, Karl-Heinz; Haase, Andrea; Hund-Rinke, Kerstin; Jakubowski, Norbert; Kearns, Peter; Lampen, Alfonso; Rauscher, Hubert; Schoonjans, Reinhilde; Störmer, Angela; Thielmann, Axel; Mühle, Uwe; Luch, Andreas

2018-01-01

Development and market introduction of new nanomaterials trigger the need for an adequate risk assessment of such products alongside suitable risk communication measures. Current application of classical and new nanomaterials is analyzed in context of regulatory requirements and standardization for chemicals, food and consumer products. The challenges of nanomaterial characterization as the main bottleneck of risk assessment and regulation are presented. In some areas, e.g., quantification of nanomaterials within complex matrices, the establishment and adaptation of analytical techniques such as laser ablation inductively coupled plasma mass spectrometry and others are potentially suited to meet the requirements. As an example, we here provide an approach for the reliable characterization of human exposure to nanomaterials resulting from food packaging. Furthermore, results of nanomaterial toxicity and ecotoxicity testing are discussed, with concluding key criteria such as solubility and fiber rigidity as important parameters to be considered in material development and regulation. Although an analysis of the public opinion has revealed a distinguished rating depending on the particular field of application, a rather positive perception of nanotechnology could be ascertained for the German public in general. An improvement of material characterization in both toxicological testing as well as end-product control was concluded as being the main obstacle to ensure not only safe use of materials, but also wide acceptance of this and any novel technology in the general public.

A brief review of the occurrence, use, and safety of food-related nanomaterials.

PubMed

Magnuson, Bernadene A; Jonaitis, Tomas S; Card, Jeffrey W

2011-08-01

Nanotechnology and nanomaterials have tremendous potential to enhance the food supply through novel applications, including nutrient and bioactive absorption and delivery systems; ingredient functionality; improved colors and flavors; microbial, allergen, and contaminant detection and control; and food packaging properties and performance. To determine the current state of knowledge regarding the safety of these potential uses of nanomaterials, an appraisal of the published literature on the safety of food-related nanomaterials was undertaken. A method of assessment of reliability of toxicology studies was developed to conduct this appraisal. The review of the toxicology literature on oral exposure to food-related nanomaterials found that the number of studies is limited. Exposure to nanomaterials in the human food chain may occur not only through intentional uses in food manufacturing, but also via uses in agricultural production and carry over from use in other industries. Although a number of analytical methods are useful in physicochemical characterization of manufactured nanomaterials, new methods may be needed to more fully detect and characterize nanomaterials incorporated into foods and in other media. There is a need for additional toxicology studies of sufficient quality and duration on different types of nanomaterials to further our understanding of the characteristics of nanomaterials that affect safety of oral exposure resulting from use in various food applications. © 2011 Institute of Food Technologists®

Grouping and Read-Across Approaches for Risk Assessment of Nanomaterials

PubMed Central

Oomen, Agnes G.; Bleeker, Eric A. J.; Bos, Peter M. J.; van Broekhuizen, Fleur; Gottardo, Stefania; Groenewold, Monique; Hristozov, Danail; Hund-Rinke, Kerstin; Irfan, Muhammad-Adeel; Marcomini, Antonio; Peijnenburg, Willie J. G. M.; Rasmussen, Kirsten; Sánchez Jiménez, Araceli; Scott-Fordsmand, Janeck J.; van Tongeren, Martie; Wiench, Karin; Wohlleben, Wendel; Landsiedel, Robert

2015-01-01

Physicochemical properties of chemicals affect their exposure, toxicokinetics/fate and hazard, and for nanomaterials, the variation of these properties results in a wide variety of materials with potentially different risks. To limit the amount of testing for risk assessment, the information gathering process for nanomaterials needs to be efficient. At the same time, sufficient information to assess the safety of human health and the environment should be available for each nanomaterial. Grouping and read-across approaches can be utilised to meet these goals. This article presents different possible applications of grouping and read-across for nanomaterials within the broader perspective of the MARINA Risk Assessment Strategy (RAS), as developed in the EU FP7 project MARINA. Firstly, nanomaterials can be grouped based on limited variation in physicochemical properties to subsequently design an efficient testing strategy that covers the entire group. Secondly, knowledge about exposure, toxicokinetics/fate or hazard, for example via properties such as dissolution rate, aspect ratio, chemical (non-)activity, can be used to organise similar materials in generic groups to frame issues that need further attention, or potentially to read-across. Thirdly, when data related to specific endpoints is required, read-across can be considered, using data from a source material for the target nanomaterial. Read-across could be based on a scientifically sound justification that exposure, distribution to the target (fate/toxicokinetics) and hazard of the target material are similar to, or less than, the source material. These grouping and read-across approaches pave the way for better use of available information on nanomaterials and are flexible enough to allow future adaptations related to scientific developments. PMID:26516872

Grouping and Read-Across Approaches for Risk Assessment of Nanomaterials.

PubMed

Oomen, Agnes G; Bleeker, Eric A J; Bos, Peter M J; van Broekhuizen, Fleur; Gottardo, Stefania; Groenewold, Monique; Hristozov, Danail; Hund-Rinke, Kerstin; Irfan, Muhammad-Adeel; Marcomini, Antonio; Peijnenburg, Willie J G M; Rasmussen, Kirsten; Jiménez, Araceli Sánchez; Scott-Fordsmand, Janeck J; van Tongeren, Martie; Wiench, Karin; Wohlleben, Wendel; Landsiedel, Robert

2015-10-26

Physicochemical properties of chemicals affect their exposure, toxicokinetics/fate and hazard, and for nanomaterials, the variation of these properties results in a wide variety of materials with potentially different risks. To limit the amount of testing for risk assessment, the information gathering process for nanomaterials needs to be efficient. At the same time, sufficient information to assess the safety of human health and the environment should be available for each nanomaterial. Grouping and read-across approaches can be utilised to meet these goals. This article presents different possible applications of grouping and read-across for nanomaterials within the broader perspective of the MARINA Risk Assessment Strategy (RAS), as developed in the EU FP7 project MARINA. Firstly, nanomaterials can be grouped based on limited variation in physicochemical properties to subsequently design an efficient testing strategy that covers the entire group. Secondly, knowledge about exposure, toxicokinetics/fate or hazard, for example via properties such as dissolution rate, aspect ratio, chemical (non-)activity, can be used to organise similar materials in generic groups to frame issues that need further attention, or potentially to read-across. Thirdly, when data related to specific endpoints is required, read-across can be considered, using data from a source material for the target nanomaterial. Read-across could be based on a scientifically sound justification that exposure, distribution to the target (fate/toxicokinetics) and hazard of the target material are similar to, or less than, the source material. These grouping and read-across approaches pave the way for better use of available information on nanomaterials and are flexible enough to allow future adaptations related to scientific developments.

Volatile-nanoparticle-assisted optical visualization of individual carbon nanotubes and other nanomaterials

NASA Astrophysics Data System (ADS)

Jian, Muqiang; Xie, Huanhuan; Wang, Qi; Xia, Kailun; Yin, Zhe; Zhang, Mingyu; Deng, Ningqin; Wang, Luning; Ren, Tianling; Zhang, Yingying

2016-07-01

The development of nanomaterials has put forward high requirements for characterization techniques. Optical microscopy (OM), with easy accessibility and open operating spaces as compared to scanning electron microscopy, is a good choice to quickly locate materials and to be integrated with other equipment. However, OM is limited by its low resolution. Herein, we present a facile and non-destructive approach for optical observation of nanomaterials under conventional OMs with the aid of volatile nanoparticles (NPs), which can be deposited and removed in a controlled manner. The NPs deposited on the surface of nanomaterials render strong light scattering to enable the nanomaterials to become optically visible. For example, this approach enables the observation of individual carbon nanotubes (CNTs) with OMs at low magnification or even with the naked eye. Both supported CNTs on various substrates and suspended CNTs can be observed with this approach. Most importantly, the NPs can be completely removed through moderate heat treatment or laser irradiation, avoiding potential influence on the properties or subsequent applications of nanomaterials. Furthermore, we systematically investigate the deposition of various volatile NPs (up to 14 kinds) for the optical observation of nanomaterials. We also demonstrated the application of this approach on other nanomaterials, including nanowires and graphene. We showed that this approach is facile, controllable, non-destructive, and contamination-free, indicating wide potential applications.The development of nanomaterials has put forward high requirements for characterization techniques. Optical microscopy (OM), with easy accessibility and open operating spaces as compared to scanning electron microscopy, is a good choice to quickly locate materials and to be integrated with other equipment. However, OM is limited by its low resolution. Herein, we present a facile and non-destructive approach for optical observation of

Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids.

PubMed

Eichmann, Shannon L; Burnham, Nancy A

2017-09-14

Globally, a small percentage of oil is recovered from reservoirs using primary and secondary recovery mechanisms, and thus a major focus of the oil industry is toward developing new technologies to increase recovery. Many new technologies utilize surfactants, macromolecules, and even nanoparticles, which are difficult to deploy in harsh reservoir conditions and where failures cause material aggregation and sticking to rock surfaces. To combat these issues, typically material properties are adjusted, but recent studies show that adjusting the dispersing fluid chemistry could have significant impact on material survivability. Herein, the effect of injection fluid salinity and composition on nanomaterial fate is explored using atomic force microscopy (AFM). The results show that the calcium content in reservoir fluids affects the interactions of an AFM tip with a calcite surface, as surrogates for nanomaterials interacting with carbonate reservoir rock. The extreme force sensitivity of AFM provides the ability to elucidate small differences in adhesion at the pico-Newton (pN) level and provides direct information about material survivability. Increasing the calcium content mitigates adhesion at the pN-scale, a possible means to increase nanomaterial survivability in oil reservoirs or to control nanomaterial fate in other aqueous environments.

Photochemically engineering the metal-semiconductor interface for room-temperature transfer hydrogenation of nitroarenes with formic acid.

PubMed

Li, Xin-Hao; Cai, Yi-Yu; Gong, Ling-Hong; Fu, Wei; Wang, Kai-Xue; Bao, Hong-Liang; Wei, Xiao; Chen, Jie-Sheng

2014-12-08

A mild photochemical approach was applied to construct highly coupled metal-semiconductor dyads, which were found to efficiently facilitate the hydrogenation of nitrobenzene. Aniline was produced in excellent yield (>99 %, TOF: 1183) using formic acid as hydrogen source and water as solvent at room temperature. This general and green catalytic process is applicable to a wide range of nitroarenes without the involvement of high-pressure gases or sacrificial additives. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A nanomaterial release model for waste shredding using a Bayesian belief network

NASA Astrophysics Data System (ADS)

Shandilya, Neeraj; Ligthart, Tom; van Voorde, Imelda; Stahlmecke, Burkhard; Clavaguera, Simon; Philippot, Cecile; Ding, Yaobo; Goede, Henk

2018-02-01

The shredding of waste of electrical and electronic equipment (WEEE) and other products, incorporated with nanomaterials, can lead to a substantial release of nanomaterials. Considering the uncertainty, complexity, and scarcity of experimental data on release, we present the development of a Bayesian belief network (BBN) model. This baseline model aims to give a first prediction of the release of nanomaterials (excluding nanofibers) during their mechanical shredding. With a focus on the description of the model development methodology, we characterize nanomaterial release in terms of number, size, mass, and composition of released particles. Through a sensitivity analysis of the model, we find the material-specific parameters like affinity of nanomaterials to the matrix of the composite and their state of dispersion inside the matrix to reduce the nanomaterial release up to 50%. The shredder-specific parameters like number of shafts in a shredder and input and output size of the material for shredding could minimize it up to 98%. The comparison with two experimental test cases shows promising outcome on the prediction capacity of the model. As additional experimental data on nanomaterial release becomes available, the model is able to further adapt and update risk forecasts. When adapting the model with additional expert beliefs, experts should be selected using criteria, e.g., substantial contribution to nanomaterial and/or particulate matter release-related scientific literature, the capacity and willingness to contribute to further development of the BBN model, and openness to accepting deviating opinions. [Figure not available: see fulltext.

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 ...

Biomarkers of nanomaterial exposure and effect: current status

NASA Astrophysics Data System (ADS)

Iavicoli, Ivo; Leso, Veruscka; Manno, Maurizio; Schulte, Paul A.

2014-03-01

Recent advances in nanotechnology have induced a widespread production and application of nanomaterials. As a consequence, an increasing number of workers are expected to undergo exposure to these xenobiotics, while the possible hazards to their health remain not being completely understood. In this context, biological monitoring may play a key role not only to identify potential hazards from and to evaluate occupational exposure to nanomaterials, but also to detect their early biological effects to better assess and manage risks of exposure in respect of the health of workers. Therefore, the aim of this review is to provide a critical evaluation of potential biomarkers of nanomaterial exposure and effect investigated in human and animal studies. Concerning exposure biomarkers, internal dose of metallic or metal oxide nanoparticle exposure may be assessed measuring the elemental metallic content in blood or urine or other biological materials, whereas specific molecules may be carefully evaluated in target tissues as possible biomarkers of biologically effective dose. Oxidative stress biomarkers, such as 8-hydroxy-deoxy-guanosine, genotoxicity biomarkers, and inflammatory response indicators may also be useful, although not specific, as biomarkers of nanomaterial early adverse health effects. Finally, potential biomarkers from "omic" technologies appear to be quite innovative and greatly relevant, although mechanistic, ethical, and practical issues should all be resolved before their routine application in occupational settings could be implemented. Although all these findings are interesting, they point out the need for further research to identify and possibly validate sensitive and specific biomarkers of exposure and effect, suitable for future use in occupational biomonitoring programs. A valuable contribution may derive from the studies investigating the biological behavior of nanomaterials and the factors influencing their toxicokinetics and reactivity. In

Cooperative nanomaterials systems for cancer diagnosis and therapeutics

NASA Astrophysics Data System (ADS)

Park, Ji Ho

The unique electromagnetic and biologic properties of nanomaterials are being harnessed to build powerful new medical technologies. Particularly, there have been recently increasing interests in cancer nanotechnology, wherein nanomaterials play an important role in ultrasensitive imaging, targeting, and therapy of cancer. However, these nanomaterials typically function as individual units and are designed to independently perform their tasks. In this dissertation, new cooperative nanosystems consisting of two distinct nanomaterials that work together to target, identify, or treat tumors in vivo were studied. In the first two chapters, the synthesis of worm-shaped dextran-coated iron oxide nanoparticles (nanoworms, NW) exhibiting substantial in vivo circulation times and significant tumor targeting when coated with tumor-homing peptides were studied. NWs are also found to display a greater magnetic resonance (MR) response than the spherical nanoparticles. Next, two types of multifunctional nanoparticles were fabricated for simultaneous detection and treatment of cancer. Micellar hybrid nanoparticles (MHN) that contain magnetic nanoparticles, quantum dots, and an anti-cancer drug doxorubicin (DOX) within a single PEG-modified phospholipid micelle were first prepared. Simultaneous multimodal imaging (MR and fluorescence) and targeted drug delivery in vitro and in vivo was performed using DOX-incorporated targeted MHN. Secondly, luminescent porous silicon nanoparticles (LPSINP) that were drug-loadable, biodegradable and relatively non-toxic were prepared. In contrast to most inorganic nanomaterials, LPSINP were degraded in vivo in a relatively short time with no noticeable toxicity. The clearance and degradation of intravenously injected LPSINP in the bladder, liver, and spleen were established by whole-body fluorescence imaging. Finally, two types of cooperative nanomaterials systems to amplify targeting and deliver drugs efficiently to regions of tumor invasion were

Toxicity of inorganic nanomaterials in biomedical imaging.

PubMed

Li, Jinxia; Chang, Xueling; Chen, Xiaoxia; Gu, Zhanjun; Zhao, Feng; Chai, Zhifang; Zhao, Yuliang

2014-01-01

Inorganic nanoparticles have shown promising potentials as novel biomedical imaging agents with high sensitivity, high spatial and temporal resolution. To translate the laboratory innovations into clinical applications, their potential toxicities are highly concerned and have to be evaluated comprehensively both in vitro and in vivo before their clinical applications. In this review, we first summarized the in vivo and in vitro toxicities of the representative inorganic nanoparticles used in biomedical imagings. Then we further discuss the origin of nanotoxicity of inorganic nanomaterials, including ROS generation and oxidative stress, chemical instability, chemical composition, the surface modification, dissolution of nanoparticles to release excess free ions of metals, metal redox state, and left-over chemicals from synthesis, etc. We intend to provide the readers a better understanding of the toxicology aspects of inorganic nanomaterials and knowledge for achieving optimized designs of safer inorganic nanomaterials for clinical applications. Copyright © 2014 Elsevier Inc. All rights reserved.

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.

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

Considerations on the EU definition of a nanomaterial: science to support policy making.

PubMed

Bleeker, Eric A J; de Jong, Wim H; Geertsma, Robert E; Groenewold, Monique; Heugens, Evelyn H W; Koers-Jacquemijns, Marjorie; van de Meent, Dik; Popma, Jan R; Rietveld, Anton G; Wijnhoven, Susan W P; Cassee, Flemming R; Oomen, Agnes G

2013-02-01

In recent years, an increasing number of applications and products containing or using nanomaterials have become available. This has raised concerns that some of these materials may introduce new risks for humans or the environment. A clear definition to discriminate nanomaterials from other materials is prerequisite to include provisions for nanomaterials in legislation. In October 2011 the European Commission published the 'Recommendation on the definition of a nanomaterial', primarily intended to provide unambiguous criteria to identify materials for which special regulatory provisions might apply, but also to promote consistency on the interpretation of the term 'nanomaterial'. In this paper, the current status of various regulatory frameworks of the European Union with regard to nanomaterials is described, and major issues relevant for regulation of nanomaterials are discussed. This will contribute to better understanding the implications of the choices policy makers have to make in further regulation of nanomaterials. Potential issues that need to be addressed and areas of research in which science can contribute are indicated. These issues include awareness on situations in which nano-related risks may occur for materials that fall outside the definition, guidance and further development of measurement techniques, and dealing with changes during the life cycle. Copyright © 2012 Elsevier Inc. All rights reserved.

Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity

PubMed Central

Cohignac, Vanessa; Landry, Marion Julie; Boczkowski, Jorge; Lanone, Sophie

2014-01-01

The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s) still remain(s) unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity. PMID:28344236

Nanomaterial synthesis and characterization for toxicological studies: TiO2 case study

USGS Publications Warehouse

Valsami-Jones, E.; Berhanu, D.; Dybowska, A.; Misra, S.; Boccaccini, A.R.; Tetley, T.D.; Luoma, S.N.; Plant, J.A.

2008-01-01

In recent years it has become apparent that the novel properties of nanomaterials may predispose them to a hitherto unknown potential for toxicity. A number of recent toxicological studies of nanomaterials exist, but these appear to be fragmented and often contradictory. Such discrepancies may be, at least in part, due to poor description of the nanomaterial or incomplete characterization, including failure to recognise impurities, surface modifications or other important physicochemical aspects of the nanomaterial. Here we make a case for the importance of good quality, well-characterized nanomaterials for future toxicological studies, combined with reliable synthesis protocols, and we present our efforts to generate such materials. The model system for which we present results is TiO2 nanoparticles, currently used in a variety of commercial products. ?? 2008 The Mineralogical Society.

Development and In Vitro Bioactivity Profiling of Alternative Sustainable Nanomaterials

EPA Science Inventory

Sustainable, environmentally benign nanomaterials (NMs) are being designed as alternatives based on functionality to conventional metal-based nanomaterials (NMs) in order to minimize potential risk to human health and the environment. Development of rapid methods to evaluate the ...

Biomedical Applications of Zinc Oxide Nanomaterials

PubMed Central

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

2013-01-01

Nanotechnology has witnessed tremendous advancement over the last several decades. Zinc oxide (ZnO), which can exhibit a wide variety of nanostructures, possesses unique semiconducting, optical, and piezoelectric properties hence has been investigated for a wide variety of applications. One of the most important features of ZnO nanomaterials is low toxicity and biodegradability. Zn2+ is an indispensable trace element for adults (~10 mg of Zn2+ per day is recommended) and it is involved in various aspects of metabolism. Chemically, the surface of ZnO is rich in -OH groups, which can be readily functionalized by various surface decorating molecules. In this review article, we summarized the current status of the use of ZnO nanomaterials for biomedical applications, such as biomedical imaging (which includes fluorescence, magnetic resonance, positron emission tomography, as well as dual-modality imaging), drug delivery, gene delivery, and biosensing of a wide array of molecules of interest. Research in biomedical applications of ZnO nanomaterials will continue to flourish over the next decade, and much research effort will be needed to develop biocompatible/biodegradable ZnO nanoplatforms for potential clinical translation. PMID:24206130

Recent developments and directions in printed nanomaterials

NASA Astrophysics Data System (ADS)

Choi, Hyung Woo; Zhou, Tianlei; Singh, Madhusudan; Jabbour, Ghassan E.

2015-02-01

In this review, we survey several recent developments in printing of nanomaterials for contacts, transistors, sensors of various kinds, light-emitting diodes, solar cells, memory devices, and bone and organ implants. The commonly used nanomaterials are classified according to whether they are conductive, semiconducting/insulating or biological in nature. While many printing processes are covered, special attention is paid to inkjet printing and roll-to-roll printing in light of their complexity and popularity. In conclusion, we present our view of the future development of this field.

Safety assessment of nanomaterials using an advanced decision-making framework, the DF4nanoGrouping

NASA Astrophysics Data System (ADS)

Landsiedel, Robert; Ma-Hock, Lan; Wiench, Karin; Wohlleben, Wendel; Sauer, Ursula G.

2017-05-01

As presented at the 2016 TechConnect World Innovation Conference on 22-25 May 2016 in Washington DC, USA, the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) `Nano Task Force' proposes a Decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping) consisting of three tiers to assign nanomaterials to four main groups with possible further subgrouping to refine specific information needs. The DF4nanoGrouping covers all relevant aspects of a nanomaterial's life cycle and biological pathways: intrinsic material properties and system-dependent properties (that depend upon the nanomaterial's respective surroundings), biopersistence, uptake and biodistribution, and cellular and apical toxic effects. Use, release, and exposure route may be applied as `qualifiers' to determine if, e.g., nanomaterials cannot be released from products, which may justify waiving of testing. The four main groups encompass (1) soluble, (2) biopersistent high aspect ratio, (3) passive, and (4) active nanomaterials. The DF4nanoGrouping foresees a stepwise evaluation of nanomaterial properties and effects with increasing biological complexity. In case studies covering carbonaceous nanomaterials, metal oxide, and metal sulfate nanomaterials, amorphous silica and organic pigments (all nanomaterials having primary particle sizes below 100 nm), the usefulness of the DF4nanoGrouping for nanomaterial hazard assessment was confirmed. The DF4nanoGrouping facilitates grouping and targeted testing of nanomaterials. It ensures that sufficient data for the risk assessment of a nanomaterial are available, and it fosters the use of non-animal methods. No studies are performed that do not provide crucial data. Thereby, the DF4nanoGrouping serves to save both animals and resources.

The effects of nanomaterials on blood coagulation in hemostasis and thrombosis.

PubMed

Simak, Jan; De Paoli, Silvia

2017-09-01

The blood coagulation balance in the organism is achieved by the interaction of the blood platelets (PLTs) with the plasma coagulation system (PCS) and the vascular endothelial cells. In healthy organism, these systems prevent thrombosis and, in events of vascular damage, enable blood clotting to stop bleeding. The dysregulation of hemostasis may cause serious thrombotic and/or hemorrhagic pathologies. Numerous engineered nanomaterials are being investigated for biomedical purposes and are unavoidably exposed to the blood. Also, nanomaterials may access vascular system after occupational, environmental, or other types of exposure. Thus, it is essential to evaluate the effects of engineered nanomaterials on hemostasis. This review focuses on investigations of nanomaterial interactions with the blood components involved in blood coagulation: the PCS and PLTs. Particular emphases include the pathophysiology of effects of nanomaterials on the PCS, including the kallikrein-kinin system, and on PLTs. Methods for investigating these interactions are briefly described, and a review of the most important studies on the interactions of nanomaterials with plasma coagulation and platelets is provided. WIREs Nanomed Nanobiotechnol 2017, 9:e1448. doi: 10.1002/wnan.1448 For further resources related to this article, please visit the WIREs website. © Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Two stage catalytic combustor

NASA Technical Reports Server (NTRS)

Alvin, Mary Anne (Inventor); Bachovchin, Dennis (Inventor); Smeltzer, Eugene E. (Inventor); Lippert, Thomas E. (Inventor); Bruck, Gerald J. (Inventor)

2010-01-01

A catalytic combustor (14) includes a first catalytic stage (30), a second catalytic stage (40), and an oxidation completion stage (49). The first catalytic stage receives an oxidizer (e.g., 20) and a fuel (26) and discharges a partially oxidized fuel/oxidizer mixture (36). The second catalytic stage receives the partially oxidized fuel/oxidizer mixture and further oxidizes the mixture. The second catalytic stage may include a passageway (47) for conducting a bypass portion (46) of the mixture past a catalyst (e.g., 41) disposed therein. The second catalytic stage may have an outlet temperature elevated sufficiently to complete oxidation of the mixture without using a separate ignition source. The oxidation completion stage is disposed downstream of the second catalytic stage and may recombine the bypass portion with a catalyst exposed portion (48) of the mixture and complete oxidation of the mixture. The second catalytic stage may also include a reticulated foam support (50), a honeycomb support, a tube support or a plate support.

Wet-chemical synthesis and applications of non-layer structured two-dimensional nanomaterials

PubMed Central

Tan, Chaoliang; Zhang, Hua

2015-01-01

Non-layer structured nanomaterials with single- or few-layer thickness have two-dimensional sheet-like structures and possess intriguing properties. Recent years have seen major advances in development of a host of non-layer structured ultrathin two-dimensional nanomaterials such as noble metals, metal oxides and metal chalcogenides. The wet-chemical synthesis has emerged as the most promising route towards high-yield and mass production of such nanomaterials. These nanomaterials are now finding increasing applications in a wide range of areas including catalysis, energy production and storage, sensor and nanotherapy, to name but a few. PMID:26303763

Potential for Occupational Exposure to Engineered Carbon-Based Nanomaterials in Environmental Laboratory Studies

PubMed Central

Johnson, David R.; Methner, Mark M.; Kennedy, Alan J.; Steevens, Jeffery A.

2010-01-01

Background The potential exists for laboratory personnel to be exposed to engineered carbon-based nanomaterials (CNMs) in studies aimed at producing conditions similar to those found in natural surface waters [e.g., presence of natural organic matter (NOM)]. Objective The goal of this preliminary investigation was to assess the release of CNMs into the laboratory atmosphere during handling and sonication into environmentally relevant matrices. Methods We measured fullerenes (C60), underivatized multiwalled carbon nanotubes (raw MWCNT), hydroxylated MWCNT (MWCNT-OH), and carbon black (CB) in air as the nanomaterials were weighed, transferred to beakers filled with reconstituted freshwater, and sonicated in deionized water and reconstituted freshwater with and without NOM. Airborne nanomaterials emitted during processing were quantified using two hand-held particle counters that measure total particle number concentration per volume of air within the nanometer range (10–1,000 nm) and six specific size ranges (300–10,000 nm). Particle size and morphology were determined by transmission electron microscopy of air sample filters. Discussion After correcting for background particle number concentrations, it was evident that increases in airborne particle number concentrations occurred for each nanomaterial except CB during weighing, with airborne particle number concentrations inversely related to particle size. Sonicating nanomaterial-spiked water resulted in increased airborne nanomaterials, most notably for MWCNT-OH in water with NOM and for CB. Conclusion Engineered nanomaterials can become airborne when mixed in solution by sonication, especially when nanomaterials are functionalized or in water containing NOM. This finding indicates that laboratory workers may be at increased risk of exposure to engineered nanomaterials. PMID:20056572

Synthesis and Technological Innovation of Applying Oxide Nanomaterials in Wastewater Treatment by Flotation

NASA Astrophysics Data System (ADS)

Covaliu, C. I.; Moga, I. C.; Matache, M. G.; Paraschiv, G.; Gageanu, I.; Vasile, E.

2018-06-01

The appearance and development of nanotechnology gave new and efficient modalities for pollutants removal from wastewaters by using new compounds called nanomaterials which possess unique structural and morphological properties. In this paper we investigated the application of CoFe2O4 nanomaterial for increasing the efficiency of oily wastewater treatment by flotation. CoFe2O4 nanomaterial was prepared by precipitation method. Prior testing their application in wastewater treatment by flotation, the oxide nanomaterial was structural and morphological characterized by XRD and TEM analyses. The influence of CoFe2O4nanomaterial on oily wastewater depollution by flotation process was investigated by measuring the following parameters: treatment efficiency [%] and the stability of froth.

Elucidating the role of surface passivating ligand structural parameters in hole wave function delocalization in semiconductor cluster molecules.

PubMed

Teunis, Meghan B; Nagaraju, Mulpuri; Dutta, Poulami; Pu, Jingzhi; Muhoberac, Barry B; Sardar, Rajesh; Agarwal, Mangilal

2017-09-28

This article describes the mechanisms underlying electronic interactions between surface passivating ligands and (CdSe) 34 semiconductor cluster molecules (SCMs) that facilitate band-gap engineering through the delocalization of hole wave functions without altering their inorganic core. We show here both experimentally and through density functional theory calculations that the expansion of the hole wave function beyond the SCM boundary into the ligand monolayer depends not only on the pre-binding energetic alignment of interfacial orbitals between the SCM and surface passivating ligands but is also strongly influenced by definable ligand structural parameters such as the extent of their π-conjugation [π-delocalization energy; pyrene (Py), anthracene (Anth), naphthalene (Naph), and phenyl (Ph)], binding mode [dithiocarbamate (DTC, -NH-CS 2 - ), carboxylate (-COO - ), and amine (-NH 2 )], and binding head group [-SH, -SeH, and -TeH]. We observe an unprecedentedly large ∼650 meV red-shift in the lowest energy optical absorption band of (CdSe) 34 SCMs upon passivating their surface with Py-DTC ligands and the trend is found to be Ph- < Naph- < Anth- < Py-DTC. This shift is reversible upon removal of Py-DTC by triethylphosphine gold(i) chloride treatment at room temperature. Furthermore, we performed temperature-dependent (80-300 K) photoluminescence lifetime measurements, which show longer lifetime at lower temperature, suggesting a strong influence of hole wave function delocalization rather than carrier trapping and/or phonon-mediated relaxation. Taken together, knowledge of how ligands electronically interact with the SCM surface is crucial to semiconductor nanomaterial research in general because it allows the tuning of electronic properties of nanomaterials for better charge separation and enhanced charge transfer, which in turn will increase optoelectronic device and photocatalytic efficiencies.

NaKnowBaseTM: The EPA Nanomaterials Research ...

EPA Pesticide Factsheets

The ability to predict the environmental and health implications of engineered nanomaterials is an important research priority due to the exponential rate at which nanotechnology is being incorporated into consumer, industrial and biomedical applications. To address this need and develop predictive capability, we have created the NaKnowbaseTM, which provides a platform for the curation and dissemination of EPA nanomaterials data to support functional assay development, hazard risk models and informatic analyses. To date, we have combined relevant physicochemical parameters from other organizations (e.g., OECD, NIST), with those requested for nanomaterial data submitted to EPA under the Toxic Substances Control Act (TSCA). Physiochemical characterization data were collated from >400 unique nanomaterials including metals, metal oxides, carbon-based and hybrid materials evaluated or synthesized by EPA researchers. We constructed parameter requirements and table structures for encoding research metadata, including experimental factors and measured response variables. As a proof of concept, we illustrate how SQL-based queries facilitate a range of interrogations including, for example, relationships between nanoparticle characteristics and environmental or toxicological endpoints. The views expressed in this poster are those of the authors and may not reflect U.S. EPA policy. The purpose of this submission for clearance is an abstract for submission to a scientific

Nanotechnology in reproductive medicine: emerging applications of nanomaterials.

PubMed

Barkalina, Natalia; Charalambous, Charis; Jones, Celine; Coward, Kevin

2014-07-01

In the last decade, nanotechnology has been extensively introduced for biomedical applications, including bio-detection, drug delivery and diagnostic imaging, particularly in the field of cancer diagnostics and treatment. However, there is a growing trend towards the expansion of nanobiotechnological tools in a number of non-cancer applications. In this review, we discuss the emerging uses of nanotechnology in reproductive medicine and reproductive biology. For the first time, we summarise the available evidence regarding the use of nanomaterials as experimental tools for the detection and treatment of malignant and benign reproductive conditions. We also present an overview of potential applications for nanomaterials in reproductive biology, discuss the benefits and concerns associated with their use in a highly delicate system of reproductive tissues and gametes, and address the feasibility of this innovative and potentially controversial approach in the clinical setting and for investigative research into the mechanisms underlying reproductive diseases. This unique review paper focuses on the emerging use of nanotechnology in reproductive medicine and reproductive biology, highlighting the role of nanomaterials in the detection and treatment of various reproductive conditions, keeping in mind the benefits and potential concerns associated with nanomaterial use in the delicate system of reproductive tissue and gametes. Copyright © 2014 Elsevier Inc. All rights reserved.

Engineering nanomaterials-based biosensors for food safety detection.

PubMed

Lv, Man; Liu, Yang; Geng, Jinhui; Kou, Xiaohong; Xin, Zhihong; Yang, Dayong

2018-05-30

Food safety always remains a grand global challenge to human health, especially in developing countries. To solve food safety pertained problems, numerous strategies have been developed to detect biological and chemical contaminants in food. Among these approaches, nanomaterials-based biosensors provide opportunity to realize rapid, sensitive, efficient and portable detection, overcoming the restrictions and limitations of traditional methods such as complicated sample pretreatment, long detection time, and relying on expensive instruments and well-trained personnel. In this review article, we provide a cross-disciplinary perspective to review the progress of nanomaterials-based biosensors for the detection of food contaminants. The review article is organized by the category of food contaminants including pathogens/toxins, heavy metals, pesticides, veterinary drugs and illegal additives. In each category of food contaminant, the biosensing strategies are summarized including optical, colorimetric, fluorescent, electrochemical, and immune- biosensors; the relevant analytes, nanomaterials and biosensors are analyzed comprehensively. Future perspectives and challenges are also discussed briefly. We envision that our review could bridge the gap between the fields of food science and nanotechnology, providing implications for the scientists or engineers in both areas to collaborate and promote the development of nanomaterials-based biosensors for food safety detection. Copyright © 2018 Elsevier B.V. All rights reserved.

Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives.

PubMed

Navya, P N; Daima, Hemant Kumar

2016-01-01

Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives

NASA Astrophysics Data System (ADS)

Navya, P. N.; Daima, Hemant Kumar

2016-02-01

Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

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2010-08-13

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Dense Plasma Focus-Based Nanofabrication of III–V Semiconductors: Unique Features and Recent Advances

PubMed Central

Mangla, Onkar; Roy, Savita; Ostrikov, Kostya (Ken)

2015-01-01

The hot and dense plasma formed in modified dense plasma focus (DPF) device has been used worldwide for the nanofabrication of several materials. In this paper, we summarize the fabrication of III–V semiconductor nanostructures using the high fluence material ions produced by hot, dense and extremely non-equilibrium plasma generated in a modified DPF device. In addition, we present the recent results on the fabrication of porous nano-gallium arsenide (GaAs). The details of morphological, structural and optical properties of the fabricated nano-GaAs are provided. The effect of rapid thermal annealing on the above properties of porous nano-GaAs is studied. The study reveals that it is possible to tailor the size of pores with annealing temperature. The optical properties of these porous nano-GaAs also confirm the possibility to tailor the pore sizes upon annealing. Possible applications of the fabricated and subsequently annealed porous nano-GaAs in transmission-type photo-cathodes and visible optoelectronic devices are discussed. These results suggest that the modified DPF is an effective tool for nanofabrication of continuous and porous III–V semiconductor nanomaterials. Further opportunities for using the modified DPF device for the fabrication of novel nanostructures are discussed as well. PMID:28344261

Dense Plasma Focus-Based Nanofabrication of III-V Semiconductors: Unique Features and Recent Advances.

PubMed

Mangla, Onkar; Roy, Savita; Ostrikov, Kostya Ken

2015-12-29

The hot and dense plasma formed in modified dense plasma focus (DPF) device has been used worldwide for the nanofabrication of several materials. In this paper, we summarize the fabrication of III-V semiconductor nanostructures using the high fluence material ions produced by hot, dense and extremely non-equilibrium plasma generated in a modified DPF device. In addition, we present the recent results on the fabrication of porous nano-gallium arsenide (GaAs). The details of morphological, structural and optical properties of the fabricated nano-GaAs are provided. The effect of rapid thermal annealing on the above properties of porous nano-GaAs is studied. The study reveals that it is possible to tailor the size of pores with annealing temperature. The optical properties of these porous nano-GaAs also confirm the possibility to tailor the pore sizes upon annealing. Possible applications of the fabricated and subsequently annealed porous nano-GaAs in transmission-type photo-cathodes and visible optoelectronic devices are discussed. These results suggest that the modified DPF is an effective tool for nanofabrication of continuous and porous III-V semiconductor nanomaterials. Further opportunities for using the modified DPF device for the fabrication of novel nanostructures are discussed as well.

Macroporous Semiconductors

PubMed Central

Föll, Helmut; Leisner, Malte; Cojocaru, Ala; Carstensen, Jürgen

2010-01-01

Pores in single crystalline semiconductors come in many forms (e.g., pore sizes from 2 nm to > 10 µm; morphologies from perfect pore crystal to fractal) and exhibit many unique properties directly or as nanocompounds if the pores are filled. The various kinds of pores obtained in semiconductors like Ge, Si, III-V, and II-VI compound semiconductors are systematically reviewed, emphasizing macropores. Essentials of pore formation mechanisms will be discussed, focusing on differences and some open questions but in particular on common properties. Possible applications of porous semiconductors, including for example high explosives, high efficiency electrodes for Li ion batteries, drug delivery systems, solar cells, thermoelectric elements and many novel electronic, optical or sensor devices, will be introduced and discussed.

Nanomaterial interactions with biomembranes: Bridging the gap between soft matter models and biological context.

PubMed

Werner, Marco; Auth, Thorsten; Beales, Paul A; Fleury, Jean Baptiste; Höök, Fredrik; Kress, Holger; Van Lehn, Reid C; Müller, Marcus; Petrov, Eugene P; Sarkisov, Lev; Sommer, Jens-Uwe; Baulin, Vladimir A

2018-04-03

Synthetic polymers, nanoparticles, and carbon-based materials have great potential in applications including drug delivery, gene transfection, in vitro and in vivo imaging, and the alteration of biological function. Nature and humans use different design strategies to create nanomaterials: biological objects have emerged from billions of years of evolution and from adaptation to their environment resulting in high levels of structural complexity; in contrast, synthetic nanomaterials result from minimalistic but controlled design options limited by the authors' current understanding of the biological world. This conceptual mismatch makes it challenging to create synthetic nanomaterials that possess desired functions in biological media. In many biologically relevant applications, nanomaterials must enter the cell interior to perform their functions. An essential transport barrier is the cell-protecting plasma membrane and hence the understanding of its interaction with nanomaterials is a fundamental task in biotechnology. The authors present open questions in the field of nanomaterial interactions with biological membranes, including: how physical mechanisms and molecular forces acting at the nanoscale restrict or inspire design options; which levels of complexity to include next in computational and experimental models to describe how nanomaterials cross barriers via passive or active processes; and how the biological media and protein corona interfere with nanomaterial functionality. In this Perspective, the authors address these questions with the aim of offering guidelines for the development of next-generation nanomaterials that function in biological media.

How light-harvesting semiconductors can alter the bias of reversible electrocatalysts in favor of H2 production and CO2 reduction.

PubMed

Bachmeier, Andreas; Wang, Vincent C C; Woolerton, Thomas W; Bell, Sophie; Fontecilla-Camps, Juan C; Can, Mehmet; Ragsdale, Stephen W; Chaudhary, Yatendra S; Armstrong, Fraser A

2013-10-09

The most efficient catalysts for solar fuel production should operate close to reversible potentials, yet possess a bias for the fuel-forming direction. Protein film electrochemical studies of Ni-containing carbon monoxide dehydrogenase and [NiFeSe]-hydrogenase, each a reversible electrocatalyst, show that the electronic state of the electrode strongly biases the direction of electrocatalysis of CO2/CO and H(+)/H2 interconversions. Attached to graphite electrodes, these enzymes show high activities for both oxidation and reduction, but there is a marked shift in bias, in favor of CO2 or H(+) reduction, when the respective enzymes are attached instead to n-type semiconductor electrodes constructed from CdS and TiO2 nanoparticles. This catalytic rectification effect can arise for a reversible electrocatalyst attached to a semiconductor electrode if the electrode transforms between semiconductor- and metallic-like behavior across the same narrow potential range (<0.25 V) that the electrocatalytic current switches between oxidation and reduction.

Shape-Controlled Synthesis of Hybrid Nanomaterials via Three-Dimensional Hydrodynamic Focusing

PubMed Central

2015-01-01

Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF–Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research. PMID:25268035

Shape-controlled synthesis of hybrid nanomaterials via three-dimensional hydrodynamic focusing.

PubMed

Lu, Mengqian; Yang, Shikuan; Ho, Yi-Ping; Grigsby, Christopher L; Leong, Kam W; Huang, Tony Jun

2014-10-28

Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF-Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research.

FOREWORD: Focus on Superconductivity in Semiconductors Focus on Superconductivity in Semiconductors

NASA Astrophysics Data System (ADS)

Takano, Yoshihiko

2008-12-01

Since the discovery of superconductivity in diamond, much attention has been given to the issue of superconductivity in semiconductors. Because diamond has a large band gap of 5.5 eV, it is called a wide-gap semiconductor. Upon heavy boron doping over 3×1020 cm-3, diamond becomes metallic and demonstrates superconductivity at temperatures below 11.4 K. This discovery implies that a semiconductor can become a superconductor upon carrier doping. Recently, superconductivity was also discovered in boron-doped silicon and SiC semiconductors. The number of superconducting semiconductors has increased. In 2008 an Fe-based superconductor was discovered in a research project on carrier doping in a LaCuSeO wide-gap semiconductor. This discovery enhanced research activities in the field of superconductivity, where many scientists place particular importance on superconductivity in semiconductors. This focus issue features a variety of topics on superconductivity in semiconductors selected from the 2nd International Workshop on Superconductivity in Diamond and Related Materials (IWSDRM2008), which was held at the National Institute for Materials Science (NIMS), Tsukuba, Japan in July 2008. The 1st workshop was held in 2005 and was published as a special issue in Science and Technology of Advanced Materials (STAM) in 2006 (Takano 2006 Sci. Technol. Adv. Mater. 7 S1). The selection of papers describe many important experimental and theoretical studies on superconductivity in semiconductors. Topics on boron-doped diamond include isotope effects (Ekimov et al) and the detailed structure of boron sites, and the relation between superconductivity and disorder induced by boron doping. Regarding other semiconductors, the superconducting properties of silicon and SiC (Kriener et al, Muranaka et al and Yanase et al) are discussed, and In2O3 (Makise et al) is presented as a new superconducting semiconductor. Iron-based superconductors are presented as a new series of high

Genotoxicity of metal oxide nanomaterials: review of recent data and discussion of possible mechanisms

NASA Astrophysics Data System (ADS)

Golbamaki, Nazanin; Rasulev, Bakhtiyor; Cassano, Antonio; Marchese Robinson, Richard L.; Benfenati, Emilio; Leszczynski, Jerzy; Cronin, Mark T. D.

2015-01-01

Nanotechnology has rapidly entered into human society, revolutionized many areas, including technology, medicine and cosmetics. This progress is due to the many valuable and unique properties that nanomaterials possess. In turn, these properties might become an issue of concern when considering potentially uncontrolled release to the environment. The rapid development of new nanomaterials thus raises questions about their impact on the environment and human health. This review focuses on the potential of nanomaterials to cause genotoxicity and summarizes recent genotoxicity studies on metal oxide/silica nanomaterials. Though the number of genotoxicity studies on metal oxide/silica nanomaterials is still limited, this endpoint has recently received more attention for nanomaterials, and the number of related publications has increased. An analysis of these peer reviewed publications over nearly two decades shows that the test most employed to evaluate the genotoxicity of these nanomaterials is the comet assay, followed by micronucleus, Ames and chromosome aberration tests. Based on the data studied, we concluded that in the majority of the publications analysed in this review, the metal oxide (or silica) nanoparticles of the same core chemical composition did not show different genotoxicity study calls (i.e. positive or negative) in the same test, although some results are inconsistent and need to be confirmed by additional experiments. Where the results are conflicting, it may be due to the following reasons: (1) variation in size of the nanoparticles; (2) variations in size distribution; (3) various purities of nanomaterials; (4) variation in surface areas for nanomaterials with the same average size; (5) differences in coatings; (6) differences in crystal structures of the same types of nanomaterials; (7) differences in size of aggregates in solution/media; (8) differences in assays; (9) different concentrations of nanomaterials in assay tests. Indeed, due to the

Payload Safety: Risk and Characteristic-Based Control of Engineered Nanomaterials

NASA Astrophysics Data System (ADS)

Abou, Seraphin Chally; Saad, Maarouf

2013-09-01

In the last decade progress has been made to assist organizations that are developing payloads intended for flight on the International Space Station (ISS) and/or Space Shuttle. Collaboration programs for comprehensive risk assessment have been initiated between the U.S. and the European Union to generate requirements and data needed to comply with payloads safety and to perform risk assessment and controls guidance. Yet, substantial research gaps remain, as do challenges in the translation of these research findings to control for exposure to nanoscale material payloads, and the health effects. Since nanomaterial structures are different from traditional molecules, some standard material properties can change at size of 50nm or less. Changes in material properties at this scale challenge our understanding of hazards posed by nanomaterial payloads in the ISS realistic exposure conditions, and our ability to anticipate, evaluate, and control potential health issues, and safety. The research question addressed in this framework is: what kind of descriptors can be developed for nanomaterial payloads risks assessment? Methods proposed incorporate elements of characteristic- based risk an alysis: (1) to enable characterization of anthropogenic nanomaterials which can result in incidental from natural nanoparticles; and (2) to better understand safety attributes in terms of human health impacts from exposure to varying types of engineered nanomaterials.

Time-Course Determination of 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 investigating potential pathways. ...

Raney nickel catalytic device

DOEpatents

O'Hare, Stephen A.

1978-01-01

A catalytic device for use in a conventional coal gasification process which includes a tubular substrate having secured to its inside surface by expansion a catalytic material. The catalytic device is made by inserting a tubular catalytic element, such as a tubular element of a nickel-aluminum alloy, into a tubular substrate and heat-treating the resulting composite to cause the tubular catalytic element to irreversibly expand against the inside surface of the substrate.

Recent Development of Nanomaterial-Doped Conductive Polymers

NASA Astrophysics Data System (ADS)

Asyraf, Mohammad; Anwar, Mahmood; Sheng, Law Ming; Danquah, Michael K.

2017-12-01

Conductive polymers (CPs) have received significant research attention in material engineering for applications in microelectronics, micro-scale sensors, electromagnetic shielding, and micro actuators. Numerous research efforts have been focused on enhancing the conductivity of CPs by doping. Various conductive materials, such as metal nanoparticles and carbon-based nanoparticles, and structures, such as silver nanoparticles and graphene nanosheets, have been converted into polypyrrole and polypyrrole compounds as the precursors to developing hybrids, conjugates, or crystal nodes within the matrix to enhance the various structural properties, particularly the electrical conductivity. This article reviews nanomaterial doping of conductive polymers alongside technological advancements in the development and application of nanomaterial-doped polymeric systems. Emphasis is given to conductive nanomaterials such as nano-silver particles and carbon-based nanoparticles, graphene nano-sheets, fullerene, and carbon nanotubes (CNT) as dopants for polypyrrole-based CPs. The nature of induced electrical properties including electromagnetic absorption, electrical capacitance, and conductivities of polypyrrole systems is also discussed. The prospects and challenges associated with the development and application of CPs are also presented.

Unitary lens semiconductor device

DOEpatents

Lear, Kevin L.

1997-01-01

A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

Nucleobases, nucleosides, and nucleotides: versatile biomolecules for generating functional nanomaterials.

PubMed

Pu, Fang; Ren, Jinsong; Qu, Xiaogang

2018-02-21

The incorporation of biomolecules into nanomaterials generates functional nanosystems with novel and advanced properties, presenting great potential for applications in various fields. Nucleobases, nucleosides and nucleotides, as building blocks of nucleic acids and biological coenzymes, constitute necessary components of the foundation of life. In recent years, as versatile biomolecules for the construction or regulation of functional nanomaterials, they have stimulated interest in researchers, due to their unique properties such as structural diversity, multiplex binding sites, self-assembly ability, stability, biocompatibility, and chirality. In this review, strategies for the synthesis of nanomaterials and the regulation of their morphologies and functions using nucleobases, nucleosides, and nucleotides as building blocks, templates or modulators are summarized alongside selected applications. The diverse applications range from sensing, bioimaging, and drug delivery to mimicking light-harvesting antenna, the construction of logic gates, and beyond. Furthermore, some perspectives and challenges in this emerging field are proposed. This review is directed toward the broader scientific community interested in biomolecule-based functional nanomaterials.

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.

Strain-controlled electrocatalysis on multimetallic nanomaterials

NASA Astrophysics Data System (ADS)

Luo, Mingchuan; Guo, Shaojun

2017-11-01

Electrocatalysis is crucial for the development of clean and renewable energy technologies, which may reduce our reliance on fossil fuels. Multimetallic nanomaterials serve as state-of-the-art electrocatalysts as a consequence of their unique physico-chemical properties. One method of enhancing the electrocatalytic performance of multimetallic nanomaterials is to tune or control the surface strain of the nanomaterials, and tremendous progress has been made in this area in the past decade. In this Review, we summarize advances in the introduction, tuning and quantification of strain in multimetallic nanocrystals to achieve more efficient energy conversion by electrocatalysis. First, we introduce the concept of strain and its correlation with other key physico-chemical properties. Then, using the electrocatalytic reduction of oxygen as a model reaction, we discuss the underlying mechanisms behind the strain-adsorption-reactivity relationship based on combined classical theories and models. We describe how this knowledge can be harnessed to design multimetallic nanocrystals with optimized strain to increase the efficiency of oxygen reduction. In particular, we highlight the unexpectedly beneficial (and previously overlooked) role of tensile strain from multimetallic nanocrystals in improving electrocatalysis. We conclude by outlining the challenges and offering our perspectives on the research directions in this burgeoning field.

In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy.

PubMed

Zhang, Kaige; Li, Gongke; Hu, Yuling

2015-10-28

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water. Herein, we demonstrate a facile method for in situ synthesis of nanocrystalline magnesium oxide-Ag(0) (nano MgO-Ag(0)) hybrid nanomaterials with dispersed Ag nanoparticles (Ag NPs) on the surface of nanocrystalline magnesium oxide (nano MgO) via Sn(2+) linkage and reduction. As a benefit from the synergy effect of nano MgO and Ag NPs, the nano MgO-Ag(0) exhibited both excellent SERS and catalytic activities for the reduction of 4-nitrothiophenol in the presence of NaBH4. The nano MgO-Ag(0) was used for real-time monitoring of the catalytic reaction process of 4-nitrothiophenol to 4-aminothiophenol in an aqueous medium by observing the SERS signals of the reactant, intermediate and final products. The intrinsic reaction kinetics and reaction mechanism of this reaction were also investigated. This SERS-based synergy technique provides a novel approach for quantitative in situ monitoring of catalytic chemical reaction processes.

Multidimensional nanomaterials for the control of stem cell fate

NASA Astrophysics Data System (ADS)

Chueng, Sy-Tsong Dean; Yang, Letao; Zhang, Yixiao; Lee, Ki-Bum

2016-09-01

Current stem cell therapy suffers low efficiency in giving rise to differentiated cell lineages, which can replace the original damaged cells. Nanomaterials, on the other hand, provide unique physical size, surface chemistry, conductivity, and topographical microenvironment to regulate stem cell differentiation through multidimensional approaches to facilitate gene delivery, cell-cell, and cell-ECM interactions. In this review, nanomaterials are demonstrated to work both alone and synergistically to guide selective stem cell differentiation. From three different nanotechnology families, three approaches are shown: (1) soluble microenvironmental factors; (2) insoluble physical microenvironment; and (3) nano-topographical features. As regenerative medicine is heavily invested in effective stem cell therapy, this review is inspired to generate discussions in the potential clinical applications of multi-dimensional nanomaterials.

Nanomaterials in Biomedicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdel-Wahhab, Mosaad A.; Márquez, Francisco

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

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

Is the risk from nanomaterials perceived as different from the risk of 'chemicals' by the Australian public?

PubMed

Capon, Adam; Rolfe, Margaret; Gillespie, James; Smith, Wayne

2016-04-15

Manufactured nanomaterials in Australia are managed predominantly through existing chemical regulatory frameworks. Many Australian government regulators have suggested the framing of manufactured nanomaterials as 'chemicals' when communicating about manufactured nanomaterials to the general public. This paper aims to determine whether the Australian public perception of manufactured nanomaterials differs to that of 'chemicals', and to examine the relationship between attitudes towards chemicals and perceptions of nanomaterial risk. We undertook a computerised assisted telephone survey of the Australian public. Analysis was undertaken using descriptive, paired tests of proportion, paired t-test and logistic regression techniques. We explored perceptions of nanomaterial risk and their relationship to perceptions of chemical risk and 'chemical attitudes'. We found that the public perceives nanomaterials in a more favourable light than it does chemicals. Perception of risk from chemicals had the greatest association with perceived nanomaterial risk (adjusted odds ratios between 0.1 and 0.2) and that attitudes to chemicals were associated with perception of nanomaterial risk in some cases. Risk communicators and policy makers need to consider the differences and associations between nanomaterials and chemicals when addressing the regulatory aspects of nanomaterials with the public. This is relevant for communication strategies that attempt to normalise the risks from nanomaterials compared with those of chemicals, especially as nanomaterials are perceived to be less risky than chemicals.

Unitary lens semiconductor device

DOEpatents

Lear, K.L.

1997-05-27

A unitary lens semiconductor device and method are disclosed. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors. 9 figs.

MAPLE deposition of nanomaterials

NASA Astrophysics Data System (ADS)

Caricato, A. P.; Arima, V.; Catalano, M.; Cesaria, M.; Cozzoli, P. D.; Martino, M.; Taurino, A.; Rella, R.; Scarfiello, R.; Tunno, T.; Zacheo, A.

2014-05-01

The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

Visible light water splitting using dye-sensitized oxide semiconductors.

PubMed

Youngblood, W Justin; Lee, Seung-Hyun Anna; Maeda, Kazuhiko; Mallouk, Thomas E

2009-12-21

Researchers are intensively investigating photochemical water splitting as a means of converting solar to chemical energy in the form of fuels. Hydrogen is a key solar fuel because it can be used directly in combustion engines or fuel cells, or combined catalytically with CO(2) to make carbon containing fuels. Different approaches to solar water splitting include semiconductor particles as photocatalysts and photoelectrodes, molecular donor-acceptor systems linked to catalysts for hydrogen and oxygen evolution, and photovoltaic cells coupled directly or indirectly to electrocatalysts. Despite several decades of research, solar hydrogen generation is efficient only in systems that use expensive photovoltaic cells to power water electrolysis. Direct photocatalytic water splitting is a challenging problem because the reaction is thermodynamically uphill. Light absorption results in the formation of energetic charge-separated states in both molecular donor-acceptor systems and semiconductor particles. Unfortunately, energetically favorable charge recombination reactions tend to be much faster than the slow multielectron processes of water oxidation and reduction. Consequently, visible light water splitting has only recently been achieved in semiconductor-based photocatalytic systems and remains an inefficient process. This Account describes our approach to two problems in solar water splitting: the organization of molecules into assemblies that promote long-lived charge separation, and catalysis of the electrolysis reactions, in particular the four-electron oxidation of water. The building blocks of our artificial photosynthetic systems are wide band gap semiconductor particles, photosensitizer and electron relay molecules, and nanoparticle catalysts. We intercalate layered metal oxide semiconductors with metal nanoparticles. These intercalation compounds, when sensitized with [Ru(bpy)(3)](2+) derivatives, catalyze the photoproduction of hydrogen from sacrificial

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

Catalytic Degradation of Dichlorvos Using Biosynthesized Zero Valent Iron Nanoparticles.

PubMed

Mehrotra, Neha; Tripathi, Ravi Mani; Zafar, Fahmina; Singh, Manoj Pratap

2017-06-01

The removal of dichlorvos contamination from water is a challenging task because of the presence of direct carbon to phosphorous covalent bond, which makes them resistant to chemical and thermal degradation. Although there have been reports in the literature for degradation of dichlorvos using nanomaterials, those are based on photocatalysis. In this paper, we report a simple and rapid method for catalytic degradation of dichlorvos using protein-capped zero valent iron nanoparticles (FeNPs). We have developed an unprecedented reliable, clean, nontoxic, eco-friendly, and cost-effective biological method for the synthesis of uniformly distributed FeNPs. Yeast extract was used as reducing and capping agent in the synthesis of FeNPs, and synthesized particles were characterized by the UV-visible spectroscopy, X -ray diffraction, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). TEM micrographs reveal that the nanoparticles size is distributed in the range of 2-10 nm. Selected area electron diffraction pattern shows the polycrystalline rings of FeNPs. The mean size was found to be 5.006 nm from ImageJ. FTIR spectra depicted the presence of biomolecules, which participated in the synthesis and stabilization of nanoparticles. As synthesized, FeNPs were used for the catalytic degradation of dichlorvos in aqueous medium. The degradation activity of the FeNPs has been investigated by the means of incubation time effect, oxidant effect, and nanoparticle concentration effect. The ammonium molybdate test was used to confirm the release of phosphate ions during the interaction of dichlorvos with FeNPs.

Nanomaterial induction of oxidative stress in lung epithelial cells and macrophages

NASA Astrophysics Data System (ADS)

Wang, Lin; Pal, Anoop K.; Isaacs, Jacqueline A.; Bello, Dhimiter; Carrier, Rebecca L.

2014-09-01

Oxidative stress in the lung epithelial A549 cells and macrophages J774A.1 due to contact with commercially important nanomaterials [i.e., nano-silver (nAg), nano-alumina (nAl2O3), single-wall carbon nanotubes (CNT), and nano-titanium oxide anatase (nTiO2)] was evaluated. Nanomaterial-induced intracellular oxidative stress was analyzed by both H2DCFDA fluorescein probe and GSH depletion, extracellular oxidative stress was assessed by H2HFF fluorescein probes, and the secretion of chemokine IL-8 by A549 cells due to elevation of cellular oxidative stress was also monitored, in order to provide a comprehensive in vitro study on nanomaterial-induced oxidative stress in lung. In addition, results from this study were also compared with an acellular "ferric reducing ability of serum" (FRAS) assay and a prokaryotic cell-based assay in evaluating oxidative damage caused by the same set of nanomaterials, for comparison purposes. In general, it was found that nanomaterial-induced oxidative stress is highly cell-type dependent. In A549 lung epithelial cells, nAg appeared to induce highest level of oxidative stress and cell death followed by CNT, nTiO2, and nAl2O3. Different biological oxidative damage (BOD) assays' (i.e., H2DCFA, GSH, and IL-8 release) results generally agreed with each other, and the same trends of nanomaterial-induced BOD were also observed in acellular FRAS and prokaryotic E. coli K12-based assay. In macrophage J774A.1 cells, nAl2O3 and nTiO2 appeared to induce highest levels of oxidative stress. These results suggest that epithelial and macrophage cell models may provide complimentary information when conducting cell-based assays to evaluate nanomaterial-induced oxidative damage in lung.

Application of dental nanomaterials: potential toxicity to the central nervous system

PubMed Central

Feng, Xiaoli; Chen, Aijie; Zhang, Yanli; Wang, Jianfeng; Shao, Longquan; Wei, Limin

2015-01-01

Nanomaterials are defined as materials with one or more external dimensions with a size of 1–100 nm. Such materials possess typical nanostructure-dependent properties (eg, chemical, biological, optical, mechanical, and magnetic), which may differ greatly from the properties of their bulk counterparts. In recent years, nanomaterials have been widely used in the production of dental materials, particularly in light polymerization composite resins and bonding systems, coating materials for dental implants, bioceramics, endodontic sealers, and mouthwashes. However, the dental applications of nanomaterials yield not only a significant improvement in clinical treatments but also growing concerns regarding their biosecurity. The brain is well protected by the blood–brain barrier (BBB), which separates the blood from the cerebral parenchyma. However, in recent years, many studies have found that nanoparticles (NPs), including nanocarriers, can transport through the BBB and locate in the central nervous system (CNS). Because the CNS may be a potential target organ of the nanomaterials, it is essential to determine the neurotoxic effects of NPs. In this review, possible dental nanomaterials and their pathways into the CNS are discussed, as well as related neurotoxicity effects underlying the in vitro and in vivo studies. Finally, we analyze the limitations of the current testing methods on the toxicological effects of nanomaterials. This review contributes to a better understanding of the nano-related risks to the CNS as well as the further development of safety assessment systems. PMID:25999717

Application of dental nanomaterials: potential toxicity to the central nervous system.

PubMed

Feng, Xiaoli; Chen, Aijie; Zhang, Yanli; Wang, Jianfeng; Shao, Longquan; Wei, Limin

2015-01-01

Nanomaterials are defined as materials with one or more external dimensions with a size of 1-100 nm. Such materials possess typical nanostructure-dependent properties (eg, chemical, biological, optical, mechanical, and magnetic), which may differ greatly from the properties of their bulk counterparts. In recent years, nanomaterials have been widely used in the production of dental materials, particularly in light polymerization composite resins and bonding systems, coating materials for dental implants, bioceramics, endodontic sealers, and mouthwashes. However, the dental applications of nanomaterials yield not only a significant improvement in clinical treatments but also growing concerns regarding their biosecurity. The brain is well protected by the blood-brain barrier (BBB), which separates the blood from the cerebral parenchyma. However, in recent years, many studies have found that nanoparticles (NPs), including nanocarriers, can transport through the BBB and locate in the central nervous system (CNS). Because the CNS may be a potential target organ of the nanomaterials, it is essential to determine the neurotoxic effects of NPs. In this review, possible dental nanomaterials and their pathways into the CNS are discussed, as well as related neurotoxicity effects underlying the in vitro and in vivo studies. Finally, we analyze the limitations of the current testing methods on the toxicological effects of nanomaterials. This review contributes to a better understanding of the nano-related risks to the CNS as well as the further development of safety assessment systems.

Carbon-based nanomaterials: multifunctional materials for biomedical engineering.

PubMed

Cha, Chaenyung; Shin, Su Ryon; Annabi, Nasim; Dokmeci, Mehmet R; Khademhosseini, Ali

2013-04-23

Functional carbon-based nanomaterials (CBNs) have become important due to their unique combinations of chemical and physical properties (i.e., thermal and electrical conductivity, high mechanical strength, and optical properties), and extensive research efforts are being made to utilize these materials for various industrial applications, such as high-strength materials and electronics. These advantageous properties of CBNs are also actively investigated in several areas of biomedical engineering. This Perspective highlights different types of carbon-based nanomaterials currently used in biomedical applications.

Bioinspired synthesis and self-assembly of hybrid organic–inorganic nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Honghu

Nature is replete with complex organic–inorganic hierarchical materials of diverse yet specific functions. These materials are intricately designed under physiological conditions through biomineralization and biological self-assembly processes. Tremendous efforts have been devoted to investigating mechanisms of such biomineralization and biological self-assembly processes as well as gaining inspiration to develop biomimetic methods for synthesis and self-assembly of functional nanomaterials. In this work, we focus on the bioinspired synthesis and self-assembly of functional inorganic nanomaterials templated by specialized macromolecules including proteins, DNA and polymers. The in vitro biomineralization process of the magnetite biomineralizing protein Mms6 has been investigated using small-angle X-ray scattering.more » Templated by Mms6, complex magnetic nanomaterials can be synthesized on surfaces and in the bulk. DNA and synthetic polymers have been exploited to construct macroscopic two- and three-dimensional (2D and 3D) superlattices of gold nanocrystals. Employing X-ray scattering and spectroscopy techniques, the self-assembled structures and the self-assembly mechanisms have been studied, and theoretical models have been developed. Our results show that specialized macromolecules including proteins, DNA and polymers act as effective templates for synthesis and self-assembly of nanomaterials. These bottom-up approaches provide promising routes to fabricate hybrid organic–inorganic nanomaterials with rationally designed hierarchical structures, targeting specific functions.« less

How should the completeness and quality of curated nanomaterial data be evaluated?†

PubMed Central

Marchese Robinson, Richard L.; Lynch, Iseult; Peijnenburg, Willie; Rumble, John; Klaessig, Fred; Marquardt, Clarissa; Rauscher, Hubert; Puzyn, Tomasz; Purian, Ronit; Åberg, Christoffer; Karcher, Sandra; Vriens, Hanne; Hoet, Peter; Hoover, Mark D.; Hendren, Christine Ogilvie; Harper, Stacey L.

2016-01-01

Nanotechnology is of increasing significance. Curation of nanomaterial data into electronic databases offers opportunities to better understand and predict nanomaterials’ behaviour. This supports innovation in, and regulation of, nanotechnology. It is commonly understood that curated data need to be sufficiently complete and of sufficient quality to serve their intended purpose. However, assessing data completeness and quality is non-trivial in general and is arguably especially difficult in the nanoscience area, given its highly multidisciplinary nature. The current article, part of the Nanomaterial Data Curation Initiative series, addresses how to assess the completeness and quality of (curated) nanomaterial data. In order to address this key challenge, a variety of related issues are discussed: the meaning and importance of data completeness and quality, existing approaches to their assessment and the key challenges associated with evaluating the completeness and quality of curated nanomaterial data. Considerations which are specific to the nanoscience area and lessons which can be learned from other relevant scientific disciplines are considered. Hence, the scope of this discussion ranges from physicochemical characterisation requirements for nanomaterials and interference of nanomaterials with nanotoxicology assays to broader issues such as minimum information checklists, toxicology data quality schemes and computational approaches that facilitate evaluation of the completeness and quality of (curated) data. This discussion is informed by a literature review and a survey of key nanomaterial data curation stakeholders. Finally, drawing upon this discussion, recommendations are presented concerning the central question: how should the completeness and quality of curated nanomaterial data be evaluated? PMID:27143028

Significance of Intratracheal Instillation Tests for the Screening of Pulmonary Toxicity of Nanomaterials.

PubMed

Morimoto, Yasuo; Izumi, Hiroto; Yoshiura, Yukiko; Fujisawa, Yuri; Fujita, Katsuhide

Inhalation tests are the gold standard test for the estimation of the pulmonary toxicity of respirable materials. Intratracheal instillation tests have been used widely, but they yield limited evidence of the harmful effects of respirable materials. We reviewed the effectiveness of intratracheal instillation tests for estimating the hazards of nanomaterials, mainly using research papers featuring intratracheal instillation and inhalation tests centered on a Japanese national project. Compared to inhalation tests, intratracheal instillation tests induced more acute inflammatory responses in the animal lung due to a bolus effect regardless of the toxicity of the nanomaterials. However, nanomaterials with high toxicity induced persistent inflammation in the chronic phase, and nanomaterials with low toxicity induced only transient inflammation. Therefore, in order to estimate the harmful effects of a nanomaterial, an observation period of 3 months or 6 months following intratracheal instillation is necessary. Among the endpoints of pulmonary toxicity, cell count and percentage of neutrophil, chemokines for neutrophils and macrophages, and oxidative stress markers are considered most important. These markers show persistent and transient responses in the lung from nanomaterials with high and low toxicity, respectively. If the evaluation of the pulmonary toxicity of nanomaterials is performed in not only the acute but also the chronic phase in order to avoid the bolus effect of intratracheal instillation and inflammatory-related factors that are used as endpoints of pulmonary toxicity, we speculate that intratracheal instillation tests can be useful for screening for the identification of the hazard of nanomaterials through pulmonary inflammation.

Decontamination of Surfaces Exposed to Carbonbased Nanotubes and Nanomaterials

NASA Astrophysics Data System (ADS)

Karimi, Zahra

Contamination of surfaces by nanomaterials can happen due to accidental spillage and release or gradual accumulation during processing or handling. Considering the increasingly wide use of nanomaterials in industry and research labs and also taking into account the diversity of physical and chemical properties of different nanomaterials (such as solubility, aggregation/agglomeration, and surface reactivity), there is a pressing need to define reliable nanomaterial-specific decontamination guidelines. In this project, we propose and investigate a potential method for surface decontamination of carbon-based nanomaterials using solvent cleaning and wipes. The results show that the surfactant-assisted removal efficiencies of multi-walled carbon nanotubes, single walled carbon nantubes and single walled carbon nano-horns from silicon wafers through wiping is greater than 95%, 90% and 78%, respectively. The need for further studies to understand the mechanisms of nanomaterial removal from surfaces and development of standard techniques for surface decontamination of nanomaterials is highlighted. Another phase of experiments were performed to examine the efficiency of surfactants to remove multi-walled carbon nanotubes (MWCNTs) from silicon substrates with nano and microscaled features. In the first set of experiments, nanoscale features were induced on silicon wafers using SF6 and O2 plasma. Atomic force microscopy (AFM) was used to observe the surface topology and roughness. In the second set, well-defined microscale topological features were induced on silicon wafers using photo lithography and plasma etching. The etching time was varied to create semi-ellipsoidal pits with average diameter and height of ~ 7-9 microm, and ~ 1-3 microm, respectively. MWCNTs in the form of liquid solution were deposited on the surface of silicon wafers using the spin coating process. For the cleaning process, the contaminated surfaces were first sprayed with different types of surfactant

Remediation of water and wastewater by using engineered nanomaterials: A review.

PubMed

Bishoge, Obadia K; Zhang, Lingling; Suntu, Shaldon L; Jin, Hui; Zewde, Abraham A; Qi, Zhongwei

2018-05-12

Nanotechnology is currently a fast-rising socioeconomic and political knowledge-based technology owing to the unique characteristics of its engineered nanomaterials. This branch of technology is useful for water and wastewater remediation. Many scientists and researchers have been conducting different studies and experiments on the applications of engineered nanomaterials at the local to international level. This review mainly aims to provide a current overview of existing knowledge on engineered nanomaterials and their applications in water and wastewater remediation. Furthermore, the present risks and challenges of nanotechnology are examined.

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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon Nanomaterials as Reinforcements for Composites

NASA Technical Reports Server (NTRS)

Zhu, Shen; Su, Ching-Hua; Lehoczky, S. L.; Curreri, Peter A. (Technical Monitor)

2002-01-01

Carbon nanomaterials including fellerenes, nanotubes (CNT) and nanofibers have been proposed for many applications. One of applications is to use the carbon nanomaterials as reinforcements for composites, especially for polymer matrices. Carbon nanotubes is a good reinforcement for lightweight composite applications due to its low mass density and high Young's modulus. Two obscures need to overcome for carbon nanotubes as reinforcements in composites, which are large quantity production and functioning the nanotubes. This presentation will discuss the carbon nanotube growth by chemical vapor deposition. In order to reduce the cost of producing carbon nanotubes as well as preventing the sliding problems, carbon nanotubes were also synthesized on carbon fibers. The synthesis process and characterization results of nanotubes and nanotubes/fibers will be discussed in the presentation.

Creating biological nanomaterials using synthetic biology.

PubMed

Rice, MaryJoe K; Ruder, Warren C

2014-02-01

Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

Fate and risks of nanomaterials in aquatic and terrestrial environments.

PubMed

Batley, Graeme E; Kirby, Jason K; McLaughlin, Michael J

2013-03-19

Over the last decade, nanoparticles have been used more frequently in industrial applications and in consumer and medical products, and these applications of nanoparticles will likely continue to increase. Concerns about the environmental fate and effects of these materials have stimulated studies to predict environmental concentrations in air, water, and soils and to determine threshold concentrations for their ecotoxicological effects on aquatic or terrestrial biota. Nanoparticles can be added to soils directly in fertilizers orplant protection products or indirectly through application to land or wastewater treatment products such as sludges or biosolids. Nanoparticles may enter aquatic systems directly through industrial discharges or from disposal of wastewater treatment effluents or indirectly through surface runoff from soils. Researchers have used laboratory experiments to begin to understand the effects of nanoparticles on waters and soils, and this Account reviews that research and the translation of those results to natural conditions. In the environment, nanoparticles can undergo a number of potential transformations that depend on the properties both of the nanoparticle and of the receiving medium. These transformations largely involve chemical and physical processes, but they can involve biodegradation of surface coatings used to stabilize many nanomaterial formulations. The toxicity of nanomaterials to algae involves adsorption to cell surfaces and disruption to membrane transport. Higher organisms can directly ingest nanoparticles, and within the food web, both aquatic and terrestrial organisms can accumulate nanoparticles. The dissolution of nanoparticles may release potentially toxic components into the environment. Aggregation with other nanoparticles (homoaggregation) or with natural mineral and organic colloids (heteroaggregation) will dramatically change their fate and potential toxicity in the environment. Soluble natural organic matter may

Redox electrodes comprised of polymer-modified carbon nanomaterials

NASA Astrophysics Data System (ADS)

Roberts, Mark; Emmett, Robert; Karakaya, Mehmet; Podila, Ramakrishna; Rao, Apparao; Clemson Physics Team; Clemson Chemical Engineering Team

2013-03-01

A shift in how we generate and use electricity requires new energy storage materials and systems compatible with hybrid electric transportation and the integration of renewable energy sources. Supercapacitors provide a solution to these needs by combining the high power, rapid switching, and exceptional cycle life of a capacitor with the high energy density of a battery. Our research brings together nanotechnology and materials chemistry to address the limitations of electrode materials. Paper electrodes fabricated with various forms of carbon nanomaterials, such as nanotubes, are modified with redox-polymers to increase the electrode's energy density while maintaining rapid discharge rates. In these systems, the carbon nanomaterials provide the high surface area, electrical conductivity, nanoscale and porosity, while the redox polymers provide a mechanism for charge storage through Faradaic charge transfer. The design of redox polymers and their incorporation into nanomaterial electrodes will be discussed with a focus on enabling high power and high energy density electrodes.

Biocompatible Nanomaterials and Nanodevices Promising for Biomedical Applications

NASA Astrophysics Data System (ADS)

Firkowska, Izabela; Giannona, Suna; Rojas-Chapana, José A.; Luecke, Klaus; Brüstle, Oliver; Giersig, Michael

Nanotechnology applied to biology requires a thorough understanding of how molecules, sub-cellular entities, cells, tissues, and organs function and how they are structured. The merging of nanomaterials and life science into hybrids of controlled organization and function is possible, assuming that biology is nanostructured, and therefore man-made nano-materials can structurally mimic nature and complement each other. By taking advantage of their special properties, nanomaterials can stimulate, respond to and interact with target cells and tissues in controlled ways to induce desired physiological responses with a minimum of undesirable effects. To fulfill this goal the fabrication of nano-engineered materials and devices has to consider the design of natural systems. Thus, engineered micro-nano-featured systems can be applied to biology and biomedicine to enable new functionalities and new devices. These include, among others, nanostructured implants providing many advantages over existing, conventional ones, nanodevices for cell manipulation, and nanosensors that would provide reliable information on biological processes and functions.

Synthetic biology engineering of biofilms as nanomaterials factories.

PubMed

Nguyen, Peter Q

2017-06-15

Bottom-up fabrication of nanoscale materials has been a significant focus in materials science for expanding our technological frontiers. This assembly concept, however, is old news to biology - all living organisms fabricate themselves using bottom-up principles through a vast self-organizing system of incredibly complex biomolecules, a marvelous dynamic that we are still attempting to unravel. Can we use what we have gleaned from biology thus far to illuminate alternative strategies for designer nanomaterial manufacturing? In the present review article, new synthetic biology efforts toward using bacterial biofilms as platforms for the synthesis and secretion of programmable nanomaterials are described. Particular focus is given to self-assembling functional amyloids found in bacterial biofilms as re-engineerable modular nanomolecular components. Potential applications and existing challenges for this technology are also explored. This novel approach for repurposing biofilm systems will enable future technologies for using engineered living systems to grow artificial nanomaterials. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

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

Photochemistry of Inorganic Nanomaterials for Solar Energy Conversion

NASA Astrophysics Data System (ADS)

Shelton, Timothy L.

systematically varying the amount of catalyst, concentration of the electron acceptor, pH of the solution, and light intensity. A decrease in activity is shown to be the result of particle agglomeration after roughly 5 hours of illumination. A maximum O2 evolution rate of 35.2 mumol O 2 h-1 is observed from an optimized system, with a QE of 0.19%, and TON of 2.58 based on total beta-FeO(OH). Chapter 4 continues to understand charge separation and transport in CdS nanorods. These nanomaterials are capable of catalytic proton reduction under visible illumination, but suffer from photo-corrosion resulting in decreased H2 production. SPS measurements show a maximum photovoltage of -230 mV at 2.75 eV and the charge separation is largely reversible. Coating the rods with graphitic carbon nitride (g-C3N4) creates a hole accepting protective layer than prevents oxidative loss of photo-activity. By adding platinum salts, additional photovoltage could be extracted through field induced charge migration from excited sub gap defect states and trap sites. The addition of a sacrificial reagent would either decrease or increase the photovoltage (depending on the reagent used) by creating additional bias in the films or charge recombination pathways. Finally, it was shown that varying the substrate has an effect on the platinum/substrate polarized charge injection. Chapter 5 Surface photovoltage is used to show for the first time the charge separation properties of Sn2TiO4, an n-type photocatalyst, a series of cuprous niobium oxides doped with tantalum (CuNb1-yTa yOx), and a Cu (I) tantalum oxide Cu5Ta11 O3.

A decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping).

PubMed

Arts, Josje H E; Hadi, Mackenzie; Irfan, Muhammad-Adeel; Keene, Athena M; Kreiling, Reinhard; Lyon, Delina; Maier, Monika; Michel, Karin; Petry, Thomas; Sauer, Ursula G; Warheit, David; Wiench, Karin; Wohlleben, Wendel; Landsiedel, Robert

2015-03-15

The European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) 'Nano Task Force' proposes a Decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping) that consists of 3 tiers to assign nanomaterials to 4 main groups, to perform sub-grouping within the main groups and to determine and refine specific information needs. The DF4nanoGrouping covers all relevant aspects of a nanomaterial's life cycle and biological pathways, i.e. intrinsic material and system-dependent properties, biopersistence, uptake and biodistribution, cellular and apical toxic effects. Use (including manufacture), release and route of exposure are applied as 'qualifiers' within the DF4nanoGrouping to determine if, e.g. nanomaterials cannot be released from a product matrix, which may justify the waiving of testing. The four main groups encompass (1) soluble nanomaterials, (2) biopersistent high aspect ratio nanomaterials, (3) passive nanomaterials, and (4) active nanomaterials. The DF4nanoGrouping aims to group nanomaterials by their specific mode-of-action that results in an apical toxic effect. This is eventually directed by a nanomaterial's intrinsic properties. However, since the exact correlation of intrinsic material properties and apical toxic effect is not yet established, the DF4nanoGrouping uses the 'functionality' of nanomaterials for grouping rather than relying on intrinsic material properties alone. Such functionalities include system-dependent material properties (such as dissolution rate in biologically relevant media), bio-physical interactions, in vitro effects and release and exposure. The DF4nanoGrouping is a hazard and risk assessment tool that applies modern toxicology and contributes to the sustainable development of nanotechnological products. It ensures that no studies are performed that do not provide crucial data and therefore saves animals and resources. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights

Management of nanomaterials safety in research environment.

PubMed

Groso, Amela; Petri-Fink, Alke; Magrez, Arnaud; Riediker, Michael; Meyer, Thierry

2010-12-10

Despite numerous discussions, workshops, reviews and reports about responsible development of nanotechnology, information describing health and environmental risk of engineered nanoparticles or nanomaterials is severely lacking and thus insufficient for completing rigorous risk assessment on their use. However, since preliminary scientific evaluations indicate that there are reasonable suspicions that activities involving nanomaterials might have damaging effects on human health; the precautionary principle must be applied. Public and private institutions as well as industries have the duty to adopt preventive and protective measures proportionate to the risk intensity and the desired level of protection. In this work, we present a practical, 'user-friendly' procedure for a university-wide safety and health management of nanomaterials, developed as a multi-stakeholder effort (government, accident insurance, researchers and experts for occupational safety and health). The process starts using a schematic decision tree that allows classifying the nano laboratory into three hazard classes similar to a control banding approach (from Nano 3--highest hazard to Nano1--lowest hazard). Classifying laboratories into risk classes would require considering actual or potential exposure to the nanomaterial as well as statistical data on health effects of exposure. Due to the fact that these data (as well as exposure limits for each individual material) are not available, risk classes could not be determined. For each hazard level we then provide a list of required risk mitigation measures (technical, organizational and personal). The target 'users' of this safety and health methodology are researchers and safety officers. They can rapidly access the precautionary hazard class of their activities and the corresponding adequate safety and health measures. We succeed in convincing scientist dealing with nano-activities that adequate safety measures and management are promoting

Management of nanomaterials safety in research environment

PubMed Central

2010-01-01

Despite numerous discussions, workshops, reviews and reports about responsible development of nanotechnology, information describing health and environmental risk of engineered nanoparticles or nanomaterials is severely lacking and thus insufficient for completing rigorous risk assessment on their use. However, since preliminary scientific evaluations indicate that there are reasonable suspicions that activities involving nanomaterials might have damaging effects on human health; the precautionary principle must be applied. Public and private institutions as well as industries have the duty to adopt preventive and protective measures proportionate to the risk intensity and the desired level of protection. In this work, we present a practical, 'user-friendly' procedure for a university-wide safety and health management of nanomaterials, developed as a multi-stakeholder effort (government, accident insurance, researchers and experts for occupational safety and health). The process starts using a schematic decision tree that allows classifying the nano laboratory into three hazard classes similar to a control banding approach (from Nano 3 - highest hazard to Nano1 - lowest hazard). Classifying laboratories into risk classes would require considering actual or potential exposure to the nanomaterial as well as statistical data on health effects of exposure. Due to the fact that these data (as well as exposure limits for each individual material) are not available, risk classes could not be determined. For each hazard level we then provide a list of required risk mitigation measures (technical, organizational and personal). The target 'users' of this safety and health methodology are researchers and safety officers. They can rapidly access the precautionary hazard class of their activities and the corresponding adequate safety and health measures. We succeed in convincing scientist dealing with nano-activities that adequate safety measures and management are promoting

Improved Stability and Performance of Visible Photoelectrochemical Water Splitting on Solution-Processed Organic Semiconductor Thin Films by Ultrathin Metal Oxide Passivation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lei; Yan, Danhua; Shaffer, David W.

Solution-processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability and photocatalytic activity. In this study, we demonstrate the direct visible PEC water oxidation on solution-processed organic semiconductor thin films with improved stability and performance by ultrathin metal oxide passivation layers. N-type fullerene-derivative thin films passivated by sub-2 nm ZnO via atomic layer deposition enabled the visible PEC water oxidation at wavelengths longer than 600 nm in harsh alkaline electrolyte environments with up to 30 μA/cm 2 photocurrents atmore » the thermodynamic water-oxidation equilibrium potential and the photoanode half-lifetime extended to ~1000 s. The systematic investigation reveals the enhanced water oxidation catalytic activity afforded by ZnO passivation and the charge tunneling governing the hole transfer through passivation layers. Further enhanced PEC performances were realized by improving the bottom ohmic contact to the organic semiconductor, achieving ~60 μA/cm 2 water oxidation photocurrent at the equilibrium potential, the highest values reported for organic semiconductor thin films to our knowledge. The improved stability and performance of passivated organic photoelectrodes and discovered design rationales provide useful guidelines for realizing the stable visible solar PEC water splitting based on organic semiconductor thin films.« less

Improved Stability and Performance of Visible Photoelectrochemical Water Splitting on Solution-Processed Organic Semiconductor Thin Films by Ultrathin Metal Oxide Passivation

DOE PAGES

Wang, Lei; Yan, Danhua; Shaffer, David W.; ...

2017-12-27

Solution-processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability and photocatalytic activity. In this study, we demonstrate the direct visible PEC water oxidation on solution-processed organic semiconductor thin films with improved stability and performance by ultrathin metal oxide passivation layers. N-type fullerene-derivative thin films passivated by sub-2 nm ZnO via atomic layer deposition enabled the visible PEC water oxidation at wavelengths longer than 600 nm in harsh alkaline electrolyte environments with up to 30 μA/cm 2 photocurrents atmore » the thermodynamic water-oxidation equilibrium potential and the photoanode half-lifetime extended to ~1000 s. The systematic investigation reveals the enhanced water oxidation catalytic activity afforded by ZnO passivation and the charge tunneling governing the hole transfer through passivation layers. Further enhanced PEC performances were realized by improving the bottom ohmic contact to the organic semiconductor, achieving ~60 μA/cm 2 water oxidation photocurrent at the equilibrium potential, the highest values reported for organic semiconductor thin films to our knowledge. The improved stability and performance of passivated organic photoelectrodes and discovered design rationales provide useful guidelines for realizing the stable visible solar PEC water splitting based on organic semiconductor thin films.« less

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

PubMed Central

Araujo, Karolline A S; Cury, Luiz A; Matos, Matheus J S; Fernandes, Thales F D; Cançado, Luiz G

2018-01-01

The influence of graphene and retinoic acid (RA) – a π-conjugated organic semiconductor – interface on their hybrid system is investigated. The physical properties of the interface are assessed via scanning probe microscopy, optical spectroscopy (photoluminescence and Raman) and ab initio calculations. The graphene/RA interaction induces the formation of a well-organized π-conjugated self-assembled monolayer (SAM) at the interface. Such structural organization leads to the high optical emission efficiency of the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the optical excitation of the RA monolayer generates surface potential changes on the hybrid system. In summary, interface-induced organized structures atop 2D materials may have an important impact on both design and operation of π-conjugated nanomaterial-based hybrid systems. PMID:29600157

Inhibition effect of graphene oxide on the catalytic activity of acetylcholinesterase enzyme.

PubMed

Wang, Yong; Gu, Yao; Ni, Yongnian; Kokot, Serge

2015-11-01

Variations in the enzyme activity of acetylcholinesterase (AChE) in the presence of the nano-material, graphene oxide (GO), were investigated with the use of molecular spectroscopy UV-visible and fluorescence methods. From these studies, important kinetic parameters of the enzyme were extracted; these were the maximum reaction rate, Vm , and the Michaelis constant, Km . A comparison of these parameters indicated that GO inhibited the catalytic activity of the AChE because of the presence of the AChE-GO complex. The formation of this complex was confirmed with the use of fluorescence data, which was resolved with the use of the MCR-ALS chemometrics method. Furthermore, it was found that the resonance light-scattering (RLS) intensity of AChE changed in the presence of GO. On this basis, it was demonstrated that the relationship between AChE and GO was linear and such models were used for quantitative analyses of GO. Copyright © 2015 John Wiley & Sons, Ltd.

The application of nanomaterials in controlled drug delivery for bone regeneration.

PubMed

Shi, Shuo; Jiang, Wenbao; Zhao, Tianxiao; Aifantis, Katerina E; Wang, Hui; Lin, Lei; Fan, Yubo; Feng, Qingling; Cui, Fu-zhai; Li, Xiaoming

2015-12-01

Bone regeneration is a complicated process that involves a series of biological events, such as cellular recruitment, proliferation and differentiation, and so forth, which have been found to be significantly affected by controlled drug delivery. Recently, a lot of research studies have been launched on the application of nanomaterials in controlled drug delivery for bone regeneration. In this article, the latest research progress in this area regarding the use of bioceramics-based, polymer-based, metallic oxide-based and other types of nanomaterials in controlled drug delivery for bone regeneration are reviewed and discussed, which indicates that the controlling drug delivery with nanomaterials should be a very promising treatment in orthopedics. Furthermore, some new challenges about the future research on the application of nanomaterials in controlled drug delivery for bone regeneration are described in the conclusion and perspectives part. Copyright © 2015 Wiley Periodicals, Inc.

Enzyme-Responsive Nanomaterials for Controlled Drug Delivery

PubMed Central

Hu, Quanyin; Katti, Prateek S.; Gu, Zhen

2015-01-01

Enzymes underpin physiological function and exhibit dysregulation in many disease-associated microenvironments and aberrant cell processes. Exploiting altered enzyme activity and expression for diagnostics, drug targeting, and drug release is tremendously promising. When combined with booming research in nanobiotechnology, enzyme-responsive nanomaterials for controlled drug release have achieved significant development and been studied as an important class of drug delivery devices in nanomedicine. In this review, we describe enzymes such as proteases, phospholipase and oxidoreductases that serve as delivery triggers. Subsequently, we explore recently developed enzyme-responsive nanomaterials with versatile applications for extracellular and intracellular drug delivery. We conclude by discussing future opportunities and challenges in this area. PMID:25251024

Enzyme-responsive nanomaterials for controlled drug delivery

NASA Astrophysics Data System (ADS)

Hu, Quanyin; Katti, Prateek S.; Gu, Zhen

2014-10-01

Enzymes underpin physiological function and exhibit dysregulation in many disease-associated microenvironments and aberrant cell processes. Exploiting altered enzyme activity and expression for diagnostics, drug targeting, and drug release is tremendously promising. When combined with booming research in nanobiotechnology, enzyme-responsive nanomaterials used for controlled drug release have achieved significant development and have been studied as an important class of drug delivery strategies in nanomedicine. In this review, we describe enzymes such as proteases, phospholipases and oxidoreductases that serve as delivery triggers. Subsequently, we explore recently developed enzyme-responsive nanomaterials with versatile applications for extracellular and intracellular drug delivery. We conclude by discussing future opportunities and challenges in this area.

Radiofrequency heating of nanomaterials for cancer treatment: Progress, controversies, and future development

NASA Astrophysics Data System (ADS)

Liu, Xiaoming; Chen, Hui-jiuan; Chen, Xiaodong; Alfadhl, Yasir; Yu, Junsheng; Wen, Dongsheng

2015-03-01

In recent years, the application of nanomaterials to biological and biomedicine areas has attracted intensive interest. One of the hot topics is the nanomaterial mediated radiofrequency (RF) hyperthermia or ablation, i.e., using RF fields/waves to heat tumor tissues treated with nanomaterials to destroy cancerous cells while minimizing the side-heating effect. However, there are currently many contradictive results reported concerning the heating effect of nanomaterials under a RF field. This paper provided a comprehensive review to nanomaterial mediated RF ablation from both experimental and theoretical aspects. Three heating mechanisms were discussed, i.e., laser heating, magnetic field heating, and electric field heating in RF spectrum, with the focus on the last one. The results showed that while diluted pure metallic nanoparticles could be heated significantly by a laser through the surface plasmon resonance, they cannot be easily heated by a RF electric field. Further studies are proposed focusing on nanoparticle structure and morphology, electromagnetic frequency and localized heating effect to pave the way for future development.

Comparative hazard analysis and toxicological modeling of diverse nanomaterials using the embryonic zebrafish (EZ) metric of toxicity

NASA Astrophysics Data System (ADS)

Harper, Bryan; Thomas, Dennis; Chikkagoudar, Satish; Baker, Nathan; Tang, Kaizhi; Heredia-Langner, Alejandro; Lins, Roberto; Harper, Stacey

2015-06-01

The integration of rapid assays, large datasets, informatics, and modeling can overcome current barriers in understanding nanomaterial structure-toxicity relationships by providing a weight-of-the-evidence mechanism to generate hazard rankings for nanomaterials. Here, we present the use of a rapid, low-cost assay to perform screening-level toxicity evaluations of nanomaterials in vivo. Calculated EZ Metric scores, a combined measure of morbidity and mortality in developing embryonic zebrafish, were established at realistic exposure levels and used to develop a hazard ranking of diverse nanomaterial toxicity. Hazard ranking and clustering analysis of 68 diverse nanomaterials revealed distinct patterns of toxicity related to both the core composition and outermost surface chemistry of nanomaterials. The resulting clusters guided the development of a surface chemistry-based model of gold nanoparticle toxicity. Our findings suggest that risk assessments based on the size and core composition of nanomaterials alone may be wholly inappropriate, especially when considering complex engineered nanomaterials. Research should continue to focus on methodologies for determining nanomaterial hazard based on multiple sub-lethal responses following realistic, low-dose exposures, thus increasing the availability of quantitative measures of nanomaterial hazard to support the development of nanoparticle structure-activity relationships.

Advancing semiconductor-electrocatalyst systems: application of surface transformation films and nanosphere lithography.

PubMed

Brinkert, Katharina; Richter, Matthias H; Akay, Ömer; Giersig, Michael; Fountaine, Katherine T; Lewerenz, Hans-Joachim

2018-05-24

Photoelectrochemical (PEC) cells offer the possibility of carbon-neutral solar fuel production through artificial photosynthesis. The pursued design involves technologically advanced III-V semiconductor absorbers coupled via an interfacial film to an electrocatalyst layer. These systems have been prepared by in situ surface transformations in electrochemical environments. High activity nanostructured electrocatalysts are required for an efficiently operating cell, optimized in their optical and electrical properties. We demonstrate that shadow nanosphere lithography (SNL) is an auspicious tool to systematically create three-dimensional electrocatalyst nanostructures on the semiconductor photoelectrode through controlling their morphology and optical properties. First results are demonstrated by means of the photoelectrochemical production of hydrogen on p-type InP photocathodes where hitherto applied photoelectrodeposition and SNL-deposited Rh electrocatalysts are compared based on their J-V and spectroscopic behavior. We show that smaller polystyrene particle masks achieve higher defect nanostructures of rhodium on the photoelectrode which leads to a higher catalytic activity and larger short circuit currents. Structural analyses including HRSEM and the analysis of the photoelectrode surface composition by using photoelectron spectroscopy support and complement the photoelectrochemical observations. The optical performance is further compared to theoretical models of the nanostructured photoelectrodes on light scattering and propagation.

Characterizing adoption of precautionary risk management guidance for nanomaterials, an emerging occupational hazard.

PubMed

Schubauer-Berigan, Mary K; Dahm, Matthew M; Schulte, Paul A; Hodson, Laura; Geraci, Charles L

2015-01-01

Exposure to engineered nanomaterials (substances with at least one dimension of 1-100 nm) has been of increased interest, with the recent growth in production and use of nanomaterials worldwide. Various organizations have recommended methods to minimize exposure to engineered nanomaterials. The purpose of this study was to evaluate available data to examine the extent to which studied U.S. companies (which represent a small fraction of all companies using certain forms of engineered nanomaterials) follow the guidelines for reducing occupational exposures to engineered nanomaterials that have been issued by the National Institute for Occupational Safety and Health (NIOSH) and other organizations. Survey data, field reports, and field notes for all NIOSH nanomaterial exposure assessments conducted between 2006 and 2011 were collected and reviewed to: (1) determine the level of adoption of precautionary guidance on engineering controls and personal protective equipment (PPE), and (2) evaluate the reliability of companies' self-reported use of engineering controls and PPE. Use of PPE was observed among 89% [95% confidence interval (CI): 76%-96%] of 46 visited companies, and use of containment-based engineering controls for at least some processes was observed among 83% (95% CI: 76%-96%). In on-site evaluations, more than 90% of the 16 engineered carbonaceous nanomaterial companies that responded to an industrywide survey were observed to be using engineering controls and PPE as reported or more stringently than reported. Since PPE use was slightly more prevalent than engineering controls, better communication may be necessary to reinforce the importance of the hierarchy of controls. These findings may also be useful in conducting exposure assessment and epidemiologic research among U.S. workers handling nanomaterials.

Soft X-ray spectromicroscopy for speciation, quantitation and nano-eco-toxicology of nanomaterials.

PubMed

Lawrence, J R; Swerhone, G D W; Dynes, J J; Korber, D R; Hitchcock, A P

2016-02-01

There is a critical need for methods that provide simultaneous detection, identification, quantitation and visualization of nanomaterials at their interface with biological and environmental systems. The approach should allow speciation as well as elemental analysis. Using the intrinsic X-ray absorption properties, soft X-ray scanning transmission X-ray spectromicroscopy (STXM) allows characterization and imaging of a broad range of nanomaterials, including metals, oxides and organic materials, and at the same time is able to provide detailed mapping of biological components. Thus, STXM offers considerable potential for application to research on nanomaterials in biology and the environment. The potential and limitations of STXM in this context are discussed using a range of examples, focusing on the interaction of nanomaterials with microbial cells, biofilms and extracellular polymers. The studies outlined include speciation and mapping of metal-containing nanomaterials (Ti, Ni, Cu) and carbon-based nanomaterials (multiwalled carbon nanotubes, C60 fullerene). The benefits of X-ray fluorescence detection in soft X-ray STXM are illustrated with a study of low levels of Ni in a natural river biofilm. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Nanomaterial Dispersion/Dissolution Characterization: Scientific Operating Procedure SOP-F-1

DTIC Science & Technology

2016-05-01

ER D C/ EL S R- 16 -1 Environmental Consequences of Nanotechnologies Nanomaterial Dispersion/Dissolution Characterization Scientific...Nanotechnologies ERDC/EL SR-16-1 May 2016 Nanomaterial Dispersion/Dissolution Characterization Scientific Operating Procedure SOP-F-1 Lesley Miller...diagnostic application. While microscopy represents the only available method for measuring particle size, this is very labor intensive and prone to

Polymer coated CaAl-layered double hydroxide nanomaterials for potential calcium supplement.

PubMed

Kim, Tae-Hyun; Lee, Jeong-A; Choi, Soo-Jin; Oh, Jae-Min

2014-12-05

We have successfully prepared layered double hydroxide (LDH) nanomaterials containing calcium and aluminum ions in the framework (CaAl-LDH). The surface of CaAl-LDH was coated with enteric polymer, Eudragit®L 100 in order to protect nanomaterials from fast dissolution under gastric condition of pH 1.2. The X-ray diffraction patterns, Fourier transform infrared spectroscopy, scanning electron and transmission electron microscopy revealed that the pristine LDH was well prepared having hydrocalumite structure, and that the polymer effectively coated the surface of LDH without disturbing structure. From thermal analysis, it was determined that only a small amount (less than 1%) of polymer was coated on the LDH surface. Metal dissolution from LDH nanomaterials was significantly reduced upon Eudragit®L 100 coating at pH 1.2, 6.8 and 7.4, which simulates gastric, enteric and plasma conditions, respectively, and the dissolution effect was the most suppressed at pH 1.2. The LDH nanomaterials did not exhibit any significant cytotoxicity up to 1000 μg/mL and intracellular calcium concentration significantly increased in LDH-treated human intestinal cells. Pharmacokinetic study demonstrated absorption efficiency of Eudragit®L 100 coated LDH following oral administration to rats. Moreover, the LDH nanomaterials did not cause acute toxic effect in vivo. All the results suggest the great potential of CaAl-LDH nanomaterials as a calcium supplement.

Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review.

PubMed

Tang, Wang-Wang; Zeng, Guang-Ming; Gong, Ji-Lai; Liang, Jie; Xu, Piao; Zhang, Chang; Huang, Bin-Bin

2014-01-15

Nowadays nanomaterials have been widely used to remove heavy metals from water/wastewater due to their large surface area and high reactivity. Humic acid (HA) and fulvic acid (FA) exist ubiquitously in aquatic environments and have a variety of functional groups which allow them to complex with metal ions and interact with nanomaterials. These interactions can not only alter the environmental behavior of nanomaterials, but also influence the removal and transportation of heavy metals by nanomaterials. Thus, the interactions and the underlying mechanisms involved warrant specific investigations. This review outlined the effects of HA/FA on the removal of heavy metals from aqueous solutions by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials. Moreover, mechanisms involved in the interactions were discussed and potential environmental implications of HA/FA to nanomaterials and heavy metals were evaluated. © 2013.

The microwave-assisted ionic-liquid method: a promising methodology in nanomaterials.

PubMed

Ma, Ming-Guo; Zhu, Jie-Fang; Zhu, Ying-Jie; Sun, Run-Cang

2014-09-01

In recent years, the microwave-assisted ionic-liquid method has been accepted as a promising methodology for the preparation of nanomaterials and cellulose-based nanocomposites. Applications of this method in the preparation of cellulose-based nanocomposites comply with the major principles of green chemistry, that is, they use an environmentally friendly method in environmentally preferable solvents to make use of renewable materials. This minireview focuses on the recent development of the synthesis of nanomaterials and cellulose-based nanocomposites by means of the microwave-assisted ionic-liquid method. We first discuss the preparation of nanomaterials including noble metals, metal oxides, complex metal oxides, metal sulfides, and other nanomaterials by means of this method. Then we provide an overview of the synthesis of cellulose-based nanocomposites by using this method. The emphasis is on the synthesis, microstructure, and properties of nanostructured materials obtained through this methodology. Our recent research on nanomaterials and cellulose-based nanocomposites by this rapid method is summarized. In addition, the formation mechanisms involved in the microwave-assisted ionic-liquid synthesis of nanostructured materials are discussed briefly. Finally, the future perspectives of this methodology in the synthesis of nanostructured materials are proposed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Raman studies of the interactions of fibrous carbon nanomaterials with albumin

NASA Astrophysics Data System (ADS)

Wesełucha-Birczyńska, Aleksandra; Morajka, Krzysztof; Stodolak-Zych, Ewa; Długoń, Elżbieta; Dużyja, Maria; Lis, Tomasz; Gubernat, Maciej; Ziąbka, Magdalena; Błażewicz, Marta

2018-05-01

Adsorption or immobilization of proteins on synthetic surfaces is a key issue in the context of the biocompatibility of implant materials, especially those intended for the needs of cardiac surgery but also for the construction of biosensors or nanomaterials used as drug carriers. The subject of research was the analysis of Raman spectra of two types of fibrous carbon nanomaterials, of great potential for biomedical applications, incubated with human serum albumin (HSA). The first nanomaterial has been created on the layer of MWCNTs deposited by electrophoretic method (EPD) and then covered by thin film of pyrolytic carbon introduced by chemical vapor deposition process (CVD). The second material was formed from carbonized nanofibers prepared via electrospinning (ESCNFs) of polyacrylonitrile (PAN) precursor and then covered with pyrolytic carbon (CVD). The G-band blue-shift towards the position of about 1600 cm-1, observed for both studied surfaces, clearly indicates the albumin (HSA) adhesion to the surface. The G and G' (2D) peak shift was employed to assess the stress build up on the carbon nanomaterials. The surface nano- and micro-topography as well as the method of ordering the carbon nanomaterial has a significant influence on the mode of surface-protein interaction.

Surface Characterization of Nanomaterials and Nanoparticles. Important needs and challenging opportunities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Donald R.; Engelhard, Mark H.; Johnson, Grant E.

2013-08-27

This review examines the characterization challenges inherently associated with understanding nanomaterials and how surface characterization methods can help meet those challenges. In parts of the research community, there is growing recognition that many studies and published reports on the properties and behaviors of nanomaterials have involved inadequate characterization. As a consequence, the true value of the data in these reports is, at best, uncertain. As the importance of nanomaterials in fundamental research and technological applications increases, it is necessary for researchers to recognize the challenges associated with reproducible materials synthesis, maintaining desired materials properties during handling and processing, and themore » dynamic nature of nanomaterials, especially nanoparticles. Researchers also need to understand how characterization approaches (surface and otherwise) can be used to minimize synthesis surprises and to determine how (and how quickly) materials and properties change in different environments. The types of information that can be provided by traditional surface sensitive analysis methods (including X-ray photoelectron and Auger electron spectroscopies, scanning probe microscopy and secondary ion mass spectroscopy) and less common or evolving surface sensitive methods (e.g., nuclear magnetic resonance, sum frequency generation, and low and medium energy ion scattering) are discussed and various of their use in nanomaterial research are presented.« less

Glucose Sensors Based on Core@Shell Magnetic Nanomaterials and Their Application in Diabetes Management: A Review.

PubMed

Liu, Lin; Lv, Hongying; Teng, Zhenyuan; Wang, Chengyin; Wang, Guoxiu

2015-01-01

This review presents a comprehensive attempt to conclude and discuss various glucose biosensors based on core@shell magnetic nanomaterials. Owing to good biocompatibility and stability, the core@shell magnetic nanomaterials have found widespread applications in many fields and draw extensive attention. Most magnetic nanoparticles possess an intrinsic enzyme mimetic activity like natural peroxidases, which invests magnetic nanomaterials with great potential in the construction of glucose sensors. We summarize the synthesis of core@shell magnetic nanomaterials, fundamental theory of glucose sensor and the advances in glucose sensors based on core@shell magnetic nanomaterials. The aim of the review is to provide an overview of the exploitation of the core@shell magnetic nanomaterials for glucose sensors construction.

Chemistry of carbon nanomaterials: Uses of lithium nanotube salts in organic syntheses and functionalization of graphite

NASA Astrophysics Data System (ADS)

Chattopadhyay, Jayanta

transfer (SET) mechanism to functionalize carbon nanotubes with different alkyl/aryl groups. Using the reductive alkylation approach, we can also functionalize graphites by alkyl/carboxylic acid groups, making graphite soluble in organic solvents and water. Tailoring of graphite layers is also accomplished by using different metals in liquid ammonia. Finally, SWNT-epoxides/graphite epoxides are synthesized using m-CPBA. Quantification of the epoxide substituents on the nanotube/graphite surface is evaluated through the catalytic de-epoxidation reaction using MeReO 3/PPh3 as heterogeneous catalyst. In summary, the proposed covalent functionalization methods yield derivatized nanomaterials that can provide a solid platform for a number of exciting applications, ranging from material science to biomedical devices. Furthermore, the results presented in this thesis provide insight into the molecular chemistry at nano-resolution.

Organic semiconductor crystals.

PubMed

Wang, Chengliang; Dong, Huanli; Jiang, Lang; Hu, Wenping

2018-01-22

Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field-effect transistors (OFETs), light-emitting diodes (OLEDs) and photovoltaic cells (OPVs). Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long-range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure-property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state-of-art status and guide future work in this area.

Rich catalytic injection

DOEpatents

Veninger, Albert [Coventry, CT

2008-12-30

A gas turbine engine includes a compressor, a rich catalytic injector, a combustor, and a turbine. The rich catalytic injector includes a rich catalytic device, a mixing zone, and an injection assembly. The injection assembly provides an interface between the mixing zone and the combustor. The injection assembly can inject diffusion fuel into the combustor, provides flame aerodynamic stabilization in the combustor, and may include an ignition device.

Selenium and tellurium nanomaterials

NASA Astrophysics Data System (ADS)

Piacenza, Elena; Presentato, Alessandro; Zonaro, Emanuele; Lampis, Silvia; Vallini, Giovanni; Turner, Raymond J.

2018-04-01

Over the last 40 years, the rapid and exponential growth of nanotechnology led to the development of various synthesis methodologies to generate nanomaterials different in size, shape and composition to be applied in various fields. In particular, nanostructures composed of Selenium (Se) or Tellurium (Te) have attracted increasing interest, due to their intermediate nature between metallic and non-metallic elements, being defined as metalloids. Indeed, this key shared feature of Se and Te allows us the use of their compounds in a variety of applications fields, such as for manufacturing photocells, photographic exposure meters, piezoelectric devices, and thermoelectric materials, to name a few. Considering also that the chemical-physical properties of elements result to be much more emphasized when they are assembled at the nanoscale range, huge efforts have been made to develop highly effective synthesis methods to generate Se- or Te-nanomaterials. In this context, the present book chapter will explore the most used chemical and/or physical methods exploited to generate different morphologies of metalloid-nanostructures, focusing also the attention on the major advantages, drawbacks as well as the safety related to these synthetic procedures.

Simulating Exposure Concentrations of Engineered Nanomaterials in Surface Water Systems: Release of WASP8

NASA Astrophysics Data System (ADS)

Knightes, C. D.; Bouchard, D.; Zepp, R. G.; Henderson, W. M.; Han, Y.; Hsieh, H. S.; Avant, B. K.; Acrey, B.; Spear, J.

2017-12-01

The unique properties of engineered nanomaterials led to their increased production and potential release into the environment. Currently available environmental fate models developed for traditional contaminants are limited in their ability to simulate nanomaterials' environmental behavior. This is due to an incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. The well-known Water Quality Analysis Simulation Program (WASP) was updated to incorporate nanomaterial-specific processes, specifically hetero-aggregation with particulate matter. In parallel with this effort, laboratory studies were used to quantify parameter values parameters necessary for governing processes in surface waters. This presentation will discuss the recent developments in the new architecture for WASP8 and the newly constructed Advanced Toxicant Module. The module includes advanced algorithms for increased numbers of state variables: chemicals, solids, dissolved organic matter, pathogens, temperature, and salinity. This presentation will focus specifically on the incorporation of nanomaterials, with the applications of the fate and transport of hypothetical releases of Multi-Walled Carbon Nanotubes (MWCNT) and Graphene Oxide (GO) into the headwaters of a southeastern US coastal plains river. While this presentation focuses on nanomaterials, the advanced toxicant module can also simulate metals and organic contaminants.

Intramolecularly Protein-Crosslinked DNA Gels: New Biohybrid Nanomaterials with Controllable Size and Catalytic Activity.

PubMed

Zhou, Li; Morel, Mathieu; Rudiuk, Sergii; Baigl, Damien

2017-07-01

DNA micro- and nanogels-small-sized hydrogels made of a crosslinked DNA backbone-constitute new promising materials, but their functions have mainly been limited to those brought by DNA. Here a new way is described to prepare sub-micrometer-sized DNA gels of controllable crosslinking density that are able to embed novel functions, such as an enzymatic activity. It consists of using proteins, instead of traditional base-pairing assembly or covalent approaches, to form crosslinks inside individual DNA molecules, resulting in structures referred to as intramolecularly protein-crosslinked DNA gels (IPDGs). It is first shown that the addition of streptavidin to biotinylated T4DNA results in the successful formation of thermally stable IPDGs with a controllable crosslinking density, forming structures ranging from elongated to raspberry-shaped and pearl-necklace-like morphologies. Using reversible DNA condensation strategies, this paper shows that the gels can be reversibly actuated at a low crosslinking density, or further stabilized when they are highly crosslinked. Finally, by using streptavidin-protein conjugates, IPDGs with various enzymes are successfully functionalized. It is demonstrated that the enzymes keep their catalytic activity upon their incorporation into the gels, opening perspectives ranging from biotechnologies (e.g., enzyme manipulation) to nanomedicine (e.g., vectorization). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrogenation-controlled phase transition on two-dimensional transition metal dichalcogenides and their unique physical and catalytic properties.

PubMed

Qu, Yuanju; Pan, Hui; Kwok, Chi Tat

2016-09-30

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have been widely used from nanodevices to energy harvesting/storage because of their tunable physical and chemical properties. In this work, we systematically investigate the effects of hydrogenation on the structural, electronic, magnetic, and catalytic properties of 33 TMDs based on first-principles calculations. We find that the stable phases of TMD monolayers can transit from 1T to 2H phase or vice versa upon the hydrogenation. We show that the hydrogenation can switch their magnetic and electronic states accompanying with the phase transition. The hydrogenation can tune the magnetic states of TMDs among non-, ferro, para-, and antiferro-magnetism and their electronic states among semiconductor, metal, and half-metal. We further show that, out of 33 TMD monolayers, 2H-TiS 2 has impressive catalytic ability comparable to Pt in hydrogen evolution reaction in a wide range of hydrogen coverages. Our findings would shed the light on the multi-functional applications of TMDs.

Functional Carbon Nanocomposite, Optoelectronic, and Catalytic Coatings

NASA Astrophysics Data System (ADS)

Liang, Yu Teng

Over the past couple decades, fundamental research into carbon nanomaterials has produced a steady stream of groundbreaking physical science. Their record setting mechanical strength, chemical stability, and optoelectronic performance have fueled many optimistic claims regarding the breadth and pace of carbon nanotube and graphene integration. However, present synthetic, processing, and economic constraints have precluded these materials from many practical device applications. To overcome these limitations, novel synthetic techniques, processing methodologies, device geometries, and mechanistic insight were developed in this dissertation. The resulting advancements in material production and composite device performance have brought carbon nanomaterials ever closer to commercial implementation. For improved materials processing, vacuum co-deposition was first demonstrated as viable technique for forming carbon nanocomposite films without property distorting covalent modifications. Co-deposited nanoparticle, carbon nanotube, and graphene composite films enabled rapid device prototyping and compositional optimization. Cellulosic polymer stabilizers were then shown to be highly effective carbon nanomaterial dispersants, improving graphene production yields by two orders of magnitude in common organic solvents. By exploiting polarity interactions, iterative solvent exchange was used to further increase carbon nanomaterial dispersion concentrations by an additional order of magnitude, yielding concentrated inks. On top of their low causticity, these cellulosic nanomaterial inks have highly tunable viscosities, excellent film forming capacity, and outstanding thermal stability. These processing characteristics enable the efficient scaling of carbon nanomaterial coatings and device production using existing roll-to-roll fabrication techniques. Utilizing these process improvements, high-performance gas sensing, energy storage, transparent conductor, and photocatalytic

AN ASSESSMENT OF THE FATE OF METAL OXIDE NANOMATERIALS IN POROUS MEDIA

EPA Science Inventory

Developing procedures for assessing the potential environmental fate and transport of nanomaterials is an active endeavor of the environmental technical research community. Insufficient information exists for estimating the likelihood of nanomaterial deposition on natural surface...

Comparative hazard analysis and toxicological modeling of diverse nanomaterials using the embryonic zebrafish (EZ) metric of toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harper, Bryan; Thomas, Dennis G.; Chikkagoudar, Satish

The integration of rapid assays, large data sets, informatics and modeling can overcome current barriers in understanding nanomaterial structure-toxicity relationships by providing a weight-of-the-evidence mechanism to generate hazard rankings for nanomaterials. Here we present the use of a rapid, low-cost assay to perform screening-level toxicity evaluations of nanomaterials in vivo. Calculated EZ Metric scores, a combined measure of morbidity and mortality, were established at realistic exposure levels and used to develop a predictive model of nanomaterial toxicity. Hazard ranking and clustering analysis of 68 diverse nanomaterials revealed distinct patterns of toxicity related to both core composition and outermost surface chemistrymore » of nanomaterials. The resulting clusters guided the development of a predictive model of gold nanoparticle toxicity to embryonic zebrafish. In addition, our findings suggest that risk assessments based on the size and core composition of nanomaterials alone may be wholly inappropriate, especially when considering complex engineered nanomaterials. These findings reveal the need to expeditiously increase the availability of quantitative measures of nanomaterial hazard and broaden the sharing of that data and knowledge to support predictive modeling. In addition, research should continue to focus on methodologies for developing predictive models of nanomaterial hazard based on sub-lethal responses to low dose exposures.« less

Comparative hazard analysis and toxicological modeling of diverse nanomaterials using the embryonic zebrafish (EZ) metric of toxicity

DOE PAGES

Harper, Bryan; Thomas, Dennis G.; Chikkagoudar, Satish; ...

2015-06-04

The integration of rapid assays, large data sets, informatics and modeling can overcome current barriers in understanding nanomaterial structure-toxicity relationships by providing a weight-of-the-evidence mechanism to generate hazard rankings for nanomaterials. Here we present the use of a rapid, low-cost assay to perform screening-level toxicity evaluations of nanomaterials in vivo. Calculated EZ Metric scores, a combined measure of morbidity and mortality, were established at realistic exposure levels and used to develop a predictive model of nanomaterial toxicity. Hazard ranking and clustering analysis of 68 diverse nanomaterials revealed distinct patterns of toxicity related to both core composition and outermost surface chemistrymore » of nanomaterials. The resulting clusters guided the development of a predictive model of gold nanoparticle toxicity to embryonic zebrafish. In addition, our findings suggest that risk assessments based on the size and core composition of nanomaterials alone may be wholly inappropriate, especially when considering complex engineered nanomaterials. These findings reveal the need to expeditiously increase the availability of quantitative measures of nanomaterial hazard and broaden the sharing of that data and knowledge to support predictive modeling. In addition, research should continue to focus on methodologies for developing predictive models of nanomaterial hazard based on sub-lethal responses to low dose exposures.« less

Stability of biogenic metal(loid) nanomaterials related to the colloidal stabilization theory of chemical nanostructures.

PubMed

Piacenza, Elena; Presentato, Alessandro; Turner, Raymond J

2018-02-25

In the last 15 years, the exploitation of biological systems (i.e. plants, bacteria, mycelial fungi, yeasts, and algae) to produce metal(loid) (Me)-based nanomaterials has been evaluated as eco-friendly and a cost-effective alternative to the chemical synthesis processes. Although the biological mechanisms of biogenic Me-nanomaterial (Bio-Me-nanomaterials) production are not yet completely elucidated, a key advantage of such bio-nanostructures over those chemically synthesized is related to their natural thermodynamic stability, with several studies ascribed to the presence of an organic layer surrounding these Bio-Me-nanostructures. Different macromolecules (e.g. proteins, peptides, lipids, DNA, and polysaccharides) or secondary metabolites (e.g. flavonoids, terpenoids, glycosides, organic acids, and alkaloids) naturally produced by organisms have been indicated as main contributors to the stabilization of Bio-Me-nanostructures. Nevertheless, the chemical-physical mechanisms behind the ability of these molecules in providing stability to Bio-Me-nanomaterials are unknown. In this context, transposing the stabilization theory of chemically synthesized Me-nanomaterials (Ch-Me-nanomaterials) to biogenic materials can be used towards a better comprehension of macromolecules and secondary metabolites role as stabilizing agents of Bio-Me-nanomaterials. According to this theory, nanomaterials are generally featured by high thermodynamic instability in suspension, due to their high surface area and surface energy. This feature leads to the necessity to stabilize chemical nanostructures, even during or directly after their synthesis, through the development of (i) electrostatic, (ii) steric, or (iii) electrosteric interactions occurring between molecules and nanomaterials in suspension. Based on these three mechanisms, this review is focused on parallels between the stabilization of biogenic or chemical nanomaterials, suggesting which chemical-physical mechanisms may be

Cytotoxicity screening of 23 engineered nanomaterials using a test matrix of ten cell lines and three different assays

PubMed Central

2011-01-01

Background Engineered nanomaterials display unique properties that may have impact on human health, and thus require a reliable evaluation of their potential toxicity. Here, we performed a standardized in vitro screening of 23 engineered nanomaterials. We thoroughly characterized the physicochemical properties of the nanomaterials and adapted three classical in vitro toxicity assays to eliminate nanomaterial interference. Nanomaterial toxicity was assessed in ten representative cell lines. Results Six nanomaterials induced oxidative cell stress while only a single nanomaterial reduced cellular metabolic activity and none of the particles affected cell viability. Results from heterogeneous and chemically identical particles suggested that surface chemistry, surface coating and chemical composition are likely determinants of nanomaterial toxicity. Individual cell lines differed significantly in their response, dependent on the particle type and the toxicity endpoint measured. Conclusion In vitro toxicity of the analyzed engineered nanomaterials cannot be attributed to a defined physicochemical property. Therefore, the accurate identification of nanomaterial cytotoxicity requires a matrix based on a set of sensitive cell lines and in vitro assays measuring different cytotoxicity endpoints. PMID:21345205

Approaches to Develop Alternative Testing Strategies to Inform Human Health Risk Assessment of Nanomaterials.

PubMed

Stone, Vicki; Johnston, Helinor J; Balharry, Dominique; Gernand, Jeremy M; Gulumian, Mary

2016-08-01

The development of alternative testing strategies (ATS) for hazard assessment of new and emerging materials is high on the agenda of scientists, funders, and regulators. The relatively large number of nanomaterials on the market and under development means that an increasing emphasis will be placed on the use of reliable, predictive ATS when assessing their safety. We have provided recommendations as to how ATS development for assessment of nanomaterial hazard may be accelerated. Predefined search terms were used to identify the quantity and distribution of peer-reviewed publications for nanomaterial hazard assessment following inhalation, ingestion, or dermal absorption. A summary of knowledge gaps relating to nanomaterial hazard is provided to identify future research priorities and areas in which a rich data set might exist to allow ATS identification. Consultation with stakeholders (e.g., academia, industry, regulators) was critical to ensure that current expert opinion was reflected. The gap analysis revealed an abundance of studies that assessed the local and systemic impacts of inhaled particles, and so ATS are available for immediate use. Development of ATS for assessment of the dermal toxicity of chemicals is already relatively advanced, and these models should be applied to nanomaterials as relatively few studies have assessed the dermal toxicity of nanomaterials to date. Limited studies have investigated the local and systemic impacts of ingested nanomaterials. If the recommendations for research prioritization proposed are adopted, it is envisioned that a comprehensive battery of ATS can be developed to support the risk assessment process for nanomaterials. Some alternative models are available for immediate implementation, while others require more developmental work to become widely adopted. Case studies are included that can be used to inform the selection of alternative models and end points when assessing the pathogenicity of fibers and mode of

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.

Engineered nanomaterials: toward effective safety management in research laboratories.

PubMed

Groso, Amela; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Hofmann, Heinrich; Meyer, Thierry

2016-03-15

It is still unknown which types of nanomaterials and associated doses represent an actual danger to humans and environment. Meanwhile, there is consensus on applying the precautionary principle to these novel materials until more information is available. To deal with the rapid evolution of research, including the fast turnover of collaborators, a user-friendly and easy-to-apply risk assessment tool offering adequate preventive and protective measures has to be provided. Based on new information concerning the hazards of engineered nanomaterials, we improved a previously developed risk assessment tool by following a simple scheme to gain in efficiency. In the first step, using a logical decision tree, one of the three hazard levels, from H1 to H3, is assigned to the nanomaterial. Using a combination of decision trees and matrices, the second step links the hazard with the emission and exposure potential to assign one of the three nanorisk levels (Nano 3 highest risk; Nano 1 lowest risk) to the activity. These operations are repeated at each process step, leading to the laboratory classification. The third step provides detailed preventive and protective measures for the determined level of nanorisk. We developed an adapted simple and intuitive method for nanomaterial risk management in research laboratories. It allows classifying the nanoactivities into three levels, additionally proposing concrete preventive and protective measures and associated actions. This method is a valuable tool for all the participants in nanomaterial safety. The users experience an essential learning opportunity and increase their safety awareness. Laboratory managers have a reliable tool to obtain an overview of the operations involving nanomaterials in their laboratories; this is essential, as they are responsible for the employee safety, but are sometimes unaware of the works performed. Bringing this risk to a three-band scale (like other types of risks such as biological, radiation

Method of doping a semiconductor

DOEpatents

Yang, Chiang Y.; Rapp, Robert A.

1983-01-01

A method for doping semiconductor material. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient.

A review and perspective of existing research on the release of nanomaterials from solid nanocomposites

PubMed Central

2014-01-01

Advances in adding nanomaterials to various matrices have occurred in tandem with the identification of potential hazards associated with exposure to pure forms of nanomaterials. We searched multiple research publication databases and found that, relative to data generated on potential nanomaterial hazards or exposures, very little attention has focused on understanding the potential and conditions for release of nanomaterials from nanocomposites. However, as a prerequisite to exposure studying release is necessary to inform risk assessments. We identified fifty-four studies that specifically investigated the release of nanomaterials, and review them in the following release scenario groupings: machining, weathering, washing, contact and incineration. While all of the identified studies provided useful information, only half were controlled experiments. Based on these data, the debris released from solid, non-food nanocomposites contains in varying frequencies, a mixture of four types of debris. Most frequently identified are (1) particles of matrix alone, and slightly less often, the (2) matrix particles exhibit the nanomaterial partially or fully embedded; far less frequently is (3) the added nanomaterial entirely dissociated from the matrix identified: and most rare are (4) dissolved ionic forms of the added nanomaterial. The occurrence of specific debris types appeared to be dependent on the specific release scenario and environment. These data highlight that release from nanocomposites can take multiple forms and that additional research and guidance would be beneficial, allowing for more consistent characterization of the release potential of nanomaterials. In addition, these data support calls for method validation and standardization, as well as understanding how laboratory release scenarios relate to real-world conditions. Importantly, as risk is considered to be a function of the inherent hazards of a substance and the actual potential for exposure, data

A review and perspective of existing research on the release of nanomaterials from solid nanocomposites.

PubMed

Froggett, Stephan J; Clancy, Shaun F; Boverhof, Darrell R; Canady, Richard A

2014-04-07

Advances in adding nanomaterials to various matrices have occurred in tandem with the identification of potential hazards associated with exposure to pure forms of nanomaterials. We searched multiple research publication databases and found that, relative to data generated on potential nanomaterial hazards or exposures, very little attention has focused on understanding the potential and conditions for release of nanomaterials from nanocomposites. However, as a prerequisite to exposure studying release is necessary to inform risk assessments. We identified fifty-four studies that specifically investigated the release of nanomaterials, and review them in the following release scenario groupings: machining, weathering, washing, contact and incineration. While all of the identified studies provided useful information, only half were controlled experiments. Based on these data, the debris released from solid, non-food nanocomposites contains in varying frequencies, a mixture of four types of debris. Most frequently identified are (1) particles of matrix alone, and slightly less often, the (2) matrix particles exhibit the nanomaterial partially or fully embedded; far less frequently is (3) the added nanomaterial entirely dissociated from the matrix identified: and most rare are (4) dissolved ionic forms of the added nanomaterial. The occurrence of specific debris types appeared to be dependent on the specific release scenario and environment. These data highlight that release from nanocomposites can take multiple forms and that additional research and guidance would be beneficial, allowing for more consistent characterization of the release potential of nanomaterials. In addition, these data support calls for method validation and standardization, as well as understanding how laboratory release scenarios relate to real-world conditions. Importantly, as risk is considered to be a function of the inherent hazards of a substance and the actual potential for exposure, data

The Neurotoxic Potential of Engineered Nanomaterials

EPA Science Inventory

The expanding development and production of engineered nanomaterials (ENMs) have diverse and far-reaching potential benefits in consumer products, food, drugs, medical devices and for enhancing environmental cleanup and remediation. The knowledge of potential implications of ENMs...

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.

A mixture toxicity approach to predict the toxicity of Ag decorated ZnO nanomaterials.

PubMed

Azevedo, S L; Holz, T; Rodrigues, J; Monteiro, T; Costa, F M; Soares, A M V M; Loureiro, S

2017-02-01

Nanotechnology is a rising field and nanomaterials can now be found in a vast variety of products with different chemical compositions, sizes and shapes. New nanostructures combining different nanomaterials are being developed due to their enhancing characteristics when compared to nanomaterials alone. In the present study, the toxicity of a nanostructure composed by a ZnO nanomaterial with Ag nanomaterials on its surface (designated as ZnO/Ag nanostructure) was assessed using the model-organism Daphnia magna and its toxicity predicted based on the toxicity of the single components (Zn and Ag). For that ZnO and Ag nanomaterials as single components, along with its mixture prepared in the laboratory, were compared in terms of toxicity to ZnO/Ag nanostructures. Toxicity was assessed by immobilization and reproduction tests. A mixture toxicity approach was carried out using as starting point the conceptual model of Concentration Addition. The laboratory mixture of both nanomaterials showed that toxicity was dependent on the doses of ZnO and Ag used (immobilization) or presented a synergistic pattern (reproduction). The ZnO/Ag nanostructure toxicity prediction, based on the percentage of individual components, showed an increase in toxicity when compared to the expected (immobilization) and dependent on the concentration used (reproduction). This study demonstrates that the toxicity of the prepared mixture of ZnO and Ag and of the ZnO/Ag nanostructure cannot be predicted based on the toxicity of their components, highlighting the importance of taking into account the interaction between nanomaterials when assessing hazard and risk. Copyright © 2016 Elsevier B.V. All rights reserved.