Nanoscience Research Research Articles

Rapid Determination of Ethyl Alcohol in Alcoholic Beverages Using a Fluorescent Nanofiber Film

Electrospinning has been recognized as a simple, versatile, and viable technique to fabricate ultrathin nanofibers from various materials, e.g., polymers and composites, in aqueous solutions. In this study, we used polyvinyl alcohol (PVA) as a substrate to synthesize nanofibers by using an electric field between the syringe needle and PVA. The nanofibers demonstrate an immense potential for developing fluorescent detection system of ethyl alcohol from several types of beverages due to their special characteristics of a simple, albeit useful, and effective top-down fabrication process. The development of nanofibers, a fundamental understanding of electrospinning, and properties of the nanofibers, as well as their applications to determine the alcohol content in beverages by direct injection into the fiber surface, were described. This method was accomplished using a PVA nanofiber scaffold as the immobilized sensing film in samples of wine, beer, or some alcohol beverages. Various beverages were tested, which were found to contain low alcohol concentrations. The optical properties of nanofibers in an aqueous PVA solution were observed by fluorescence spectra. The PVA nanofiber films could be useful for detecting the alcohol upto 1.0vol% in a real sample within several seconds. Details of the type of electrospun fibers, and their characteristics were also explained. This study should serve as a guiding tool for nanoscience researchers in fibers, textiles, food validations, and polymer fields.

Nanoscience and Nanotechnology Research at Peking University.

Nanoscience and Nanotechnology Research at Peking University.

Evaluating microwave-synthesized silver nanoparticles from silver nitrate with life cycle assessment techniques

Silver Nanoparticles (AgNPs) are well known for applications in electronics and as antimicrobial agents because of their unique optical, electrical, cytotoxic and thermal properties. These nanoparticles can be synthesized via a wide variety of techniques; however, they require the use of hazardous solvents which have very high environmental impacts. Nanoscience researchers have attempted novel synthesis routes that reduce resource requirements and use benign chemicals, while maintaining control over their unique properties. The present study evaluates the potential environmental impacts of one such benign method using Life Cycle Assessment (LCA) techniques which are used to assess the environmental impacts of a product's life through all the stages from raw material extraction to disposal/ recycling. This research evaluates AgNPs which were synthesized using glucose as the reducing agent and food grade corn starch as the stabilizing agent in a microwave-assisted reaction system. GaBi 6.0 software was used to carry out the Life Cycle Impact Assessment on a declared unit of 1 kg of 3.0 ± 1.2 nm diameter AgNPs. The results indicate that the impacts are predominantly on acidification (AP), human health particulate air (HHAP) and human toxicity non-cancer (HTNCP) potentials. These impacts are mainly from the production of silver metal and electricity used. The starch and glucose used to produce AgNPs of 3.0 ± 1.2 nm is shown to have negligible environmental impacts and is therefore considered to be environmentally benign.

Novel Strategies to Interface Molecules and 2D Materials

One of the most attractive areas of research in Nanoscience is the combination of 2D materials through van der Waals forces to form heterostructures (Novoselov, K. S.; Mishchenko, A.; Carvalho, A.; Castro Neto, A. H. Science 2016, 353, DOI: 10.1126/science.aac9439). Here, we present strategies beyond dispersion forces to interface 0D (molecules) and 2D materials. We will show examples of 0D-2D heterostructures connected through covalent and noncovalent chemistry. In the first example, we will show a method to functionalize graphene covalently with exquisite atomic selectivity and yield (NanoLett. 2016, Chem. Commun. 2017). In the second example, we will show that the photoresponse of MoS2 photodetectors can be enhanced by simple and reversible supramolecular functionalization with organic dyes (Chem. Commun. 2016). We will also show the example of a naturally occurring van der Waals heterostructure, franckeite, an air stable, p-doped semiconductor with photoresponse in the far IR (Nat. Comms. 2017). Finally, we will present strategies for the self assembly of liquid-phase exfoliated 2D materials from suspension into functioning electronic devices (Chem. Commun. 2017).

Shed light on submerged DC arc discharge synthesis of low band gap gray Zn/ZnO nanoparticles: Formation and gradual oxidation mechanism

Synthesis of colloidal metal oxides with controllable size and morphology is burgeoning field of research in nanoscience. Low band gap gray Zn/ZnO colloidal nanoparticles were fabricated by plasma-liquid interaction of DC arc discharge in water. Scanning electron microscopy, X-ray diffraction and UV–vis spectroscopy were employed for morphology, crystal structure and optical characterizations respectively. Optical emission spectroscopy was used to investigate the plasma properties during the synthesis and formation mechanism of nanoparticles. Nanoparticles with different size and shape were fabricated only by adjusting discharge current during synthesis without introducing any chemical agent. Electric discharge current was set to 20, 50, 100 and 150 A during synthesis. Estimated values of plasma excitation energies were 2.41, 2.66, 2.86 and 3.04 eV and diameter size of nanoparticles were 63, 42, 37 and 29 nm for these applied currents respectively. Synthesized nanoparticles were dark gray as prepared and became more transparent gradually getting white color finally. XRD and UV–vis results revealed that the oxidation process was time dependent. The colloidal nanoparticles composed of two metal and metal-oxide phase and white crystalline ZnO was achieved after complete oxidation process. These results provided a flexible and versatile method to synthesize metal oxide nanoparticles with controlled composition.

Interlocking Mechanism between Molecular Gears Attached to Surfaces.

While molecular machines play an increasingly significant role in nanoscience research and applications, there remains a shortage of investigations and understanding of the molecular gear (cogwheel), which is an indispensable and fundamental component to drive a larger correlated molecular machine system. Employing ab initio calculations, we investigate model systems consisting of molecules adsorbed on metal or graphene surfaces, ranging from very simple triple-arm gears such as PF3 and NH3 to larger multiarm gears based on carbon rings. We explore in detail the transmission of slow rotational motion from one gear to the next by these relatively simple molecules, so as to isolate and reveal the mechanisms of the relevant intermolecular interactions. Several characteristics of molecular gears are discussed, in particular the flexibility of the arms and the slipping and skipping between interlocking arms of adjacent gears, which differ from familiar macroscopic rigid gears. The underlying theoretical concepts suggest strongly that other analogous structures may also exhibit similar behavior which may inspire future exploration in designing large correlated molecular machines.

Bibliometric analysis of the development of nanoscience research in South Africa


 
 
 Nanotechnology is a fast-growing scientific research area internationally and is classified as an important emerging research area. In response to this importance, South African researchers and institutions have also increased their efforts in this area. A bibliometric study of articles as indexed in the Web of Science considered the development in this field with respect to the growth in literature, collaboration profile and the research areas that are more within the country’s context. We also looked at public institutions that are more active in this arena, including government policy considerations as guided by the National Nanotechnology Strategy launched in 2005. We found that the number of nanotechnology publications have shown a remarkable growth ever since the launch of the strategy. Articles on nanotechnology have been published in numerous journals, with Electrochimica Acta publishing the most, followed by Journal of Nanoscience and Nanotechnology. These publications fall within the traditional domains of chemistry and physics. In terms of the institutional profile and based on publication outputs over the period reviewed, the Council for Scientific and Industrial Research is a leading producer of publications in nanotechnology, followed by the University of the Witwatersrand – institutions that are both based in the Gauteng Province. There is a high level of international collaboration with different countries within this field – the most productive collaboration is with India, followed by the USA and China, as measured through co-authorship.
 
 
 
 
 Significance: 
 
 
 
 Nanotechnology as a field of research is experiencing rapid growth and there is a need to understand progress from a South African perspective.
 
 
 

Facile displacement of citrate residues from gold nanoparticle surfaces

The stability of citrate-residues on gold nanoparticles (AuNPs) against ligand displacement has been controversial. Using AuNPs synthesized with deuterated citrate in combination with in-situ surface-enhanced Raman spectroscopic (SERS) analysis, we report that both citrate-residues and solution impurities can be simultaneously adsorbed onto citrate-reduced AuNPs in solution. The citrate-residues can be readily displaced from AuNPs by organosulfur such as organothiols (RS-H), organodisuflide (R-S-S-R), and non-specific ligands including halides and adenine. Control experiments conducted on high-purity gold films sputter-coated onto silicone substrates indicate that air-borne and solvent-borne impurities rapidly contaminate the gold surfaces. Head-to-head comparison of ligand-functionalized AuNPs by in-situ SERS measurements verses those from the ex-situ X-ray photoelectron spectroscopic (XPS) measurements reveal that the impurity deposition can compromise the reliability of ex-situ XPS identification of surface adsorbates on AuNPs in solution. These insights are of general significance to nanoscience research given the broad interest in nanoparticle surface chemistry and popularity of XPS for nanomaterial characterizations.

PROGNOSTICATION OF NF-ΚB AND P53 EXPRESSION IN DIFFERENT STAGE AND GRADE OF OVARIAN CANCER.

10Aug 2017 PROGNOSTICATION OF NF-ΚB AND P53 EXPRESSION IN DIFFERENT STAGE AND GRADE OF OVARIAN CANCER. Debarshi Jana , Sambhunath Bandyopadhyay , Priyanka Upadhyay , Arghya Adhikary and Asim Kumar Manna. Department of Gynecology & Obstetrics, Institute of Post-Graduate Medical Education and Research, A.J.C. Bose Road, Kolkata-700020, West Bengal, India Centre for research in nanoscience & nanotechnology, acharya prafulla chandra roy sikhsha prangan, university of Calcutta, jd-2, sector 3, salt lake city, kolkata-700108, West Bengal, India.

Highly sensitive hybrid nanofiber-based room-temperature CO sensors: Experiments and density functional theory simulations

Chemical sensors (CSs) are an emerging area in nanoscience research, which focuses on the highly sensitive detection of toxic and hazardous gases and disease-related volatile organics. While the field has advanced rapidly in recent years, it lacks the theoretical support required for the rational design of innovative materials with tunable measurement responses. Herein, we present a one-dimensional (1D) hybrid nanofiber decorated with ultrafine NiO nanoparticles (NiO NPs) as an efficient active component for CSs. Highly dispersed (110)-facet NiO NPs with a high percentage of Ni2+ active sites with unsaturated coordination were confined in a TiO2 nanofiber (TiO2 NF) matrix that is favorable for surface catalytic reactions. The CSs constructed using the 1D heterostructure NiO/TiO2 nanofibers (NiO/TiO2 HNFs) exhibited a highly selective response to trace CO gas molecules (1 ppm) with high sensitivity (ΔR/R0 = 1.02), ultrafast response/recovery time (Tres/Trecov < 20 s), and remarkable reproducibility at room temperature. The density functional theory (DFT) simulations and experimental results confirmed that the selective response could be attributed to the high molecular adsorption energy of the NiO nanoparticles with (110) facets and abundant interfaces, which act synergistically to promote CO adsorption and facilitate charge transfer.

Skewness Analysis in Variance Spectroscopy Measures Nanoparticle Individualization.

An important enabling step in nanoparticle studies is the sorting of heterogeneous mixtures to prepare structurally homogeneous samples. It is also necessary to detect and monitor aggregation of the individual nanoparticles. Although variance spectroscopy provides a simple optical method for finding low concentrations of heteroaggregates in samples such as single-walled carbon nanotube dispersions, it cannot detect the homoaggregates that are relevant for well-sorted samples. Here we demonstrate that variance spectral data can be further analyzed to find third moments of intensity distributions (skewness), which reveal the presence of emissive homoaggregates. Using experimental measurements on variously processed nanotube dispersions, we deduce a simple numerical standard for recognizing aggregation in the highly sorted samples that are increasingly available to nanoscience researchers.

Tailored Nickel Oxide Nanorods Via Hydrothermal Growth for Gas Sensors and Electrocatalysts

Nickel oxide, a p-type wide-bandgap semiconductor, is a very attractive material for various applications including catalysts, electrode materials for lithium ion batteries and fuel cells, electrochemical capacitors, electrochromic thin films, biosensors, and gas sensors. In nanoscience research the morphology-controlled synthesis is a crucial issue to change and improve properties of materials at nanoscale. Among many methods, the solution-based chemical process has developed into a promising technique because it allows to easily tune morphologies with changing experimental parameters. To achieve different aspect ratios of NiO nanostructures, a NiCl2-Na2C2O4-H2O hydrothermal system with polyethylene glycol, ethylene glycol, and glycine as surfactant was suggested. However, their work was limited to form a nanowire bundle during the chemical reaction. Therefore, a solution system to obtain a wider range of morphological features of NiO needs to be developed. In addition to synthesis of NiO nanostructure, its coating to desired substrates is important. As a possible pathway, electrophoretic deposition (EPD) can be considered because of its high versatility and low cost equipment. EPD process can also be applied to various types of substrates such as fibers, cloths and complex shaped materials. Such a flexible, soft and nonfragile substrate has been explored for flexible and wearable functional devices. In this study, nanostructured nickel oxide is synthesized using a hydrothermal method and tailored by triethanolamine. The structural properties of the nickel oxide particles were analyzed by using SEM and XRD. Strong dependence of the triethanolamine on NiO nanorods was found and their mechanism was investigated. For the fabrication of the devices, EPD of tailored nickel oxide was then used to construct nickel oxide electrodes on polyimide films for gas sensing measurements and carbon papers for electrochemical measurements. The morphology-controlled gas sensing properties of NiO were investigated with VOC gases. The performance of NiO for gas sensors were evaluated in terms of sensitivity and selectivity. The mechanism of p-type NiO for gas sensors is discussed in details. For nickel oxide catalysts, the urea electrooxidation in alkali medium were investigated and evaluated by cyclic voltammetry and chronoamperometry. In order to improve electrocatalytic activities, nickel oxide decorated by nickel and cobalt composite structures were also investigated. The work was partially supported by the KIET Evaluation and Planning (20158520000210) grant funded by the Korea Government Ministry of Trade, Industry and Energy and Agency for Defense Development (ADD) as global cooperative research for high performance and light weight bio-urine based fuel cell (UD160050BD).

Optical Beam Deflection Based AFM with Integrated Hardware and Software Platform for an Undergraduate Engineering Laboratory

Atomic force microscopy (AFM) has been used extensively in nanoscience research since its invention. Recently, many teaching laboratories in colleges, undergraduate institutions, and even high schools incorporate AFM as an effective teaching tool for nanoscience education. This paper presents an optical beam deflection (OBD) based atomic force microscope, designed specifically for the undergraduate engineering laboratory as a teaching instrument. An electronic module for signal conditioning was built with components that are commonly available in an undergraduate electronic laboratory. In addition to off-the-shelf mechanical parts and optics, the design of custom-built mechanical parts waskept as simple as possible. Hence, the overall cost for the setup is greatly reduced. The AFM controller was developed using National Instruments Educational Laboratory Virtual Instrumentation Suite (NI ELVIS), an integrated hardware and software platform which can be programmed in LabVIEW. A simple yet effective control algorithm for scanning and feedback control was developed. Despite the use of an educational platform and low-cost components from the undergraduate laboratory, the developed AFM is capable of performing imaging in constant-force mode with submicron resolution and at reasonable scanning speed (approximately 18 min per image). Therefore, the AFM is suitable to be used as an educational tool for nanoscience. Moreover, the construction of the system can be a valuable educational experience for electronic and mechanical engineering students.

Impact of newly synthesized water soluble photoluminescent ZnS-L-Cysteine: Core-shell nanoparticles in defining the in-situ opto-electronic orbital model

An intermolecular charge and electron transfer processes in photoluminescent ZnS- L-Cysteine: core-shell Nanoparticles (NPs) extend highly sensitive and variable valence at the core (ZnS)-shell (L-Cysteine) interface primarily due to an extensive mixing of materials frontier orbital (i.e. covalency). Water soluble, ZnS- L-Cysteine: core-shell photo luminescent NPs achieved by straight forward micellar route that is thrust area of research in nanoscience for the control particle size and remarkable properties through chemical co-precipitation method. In the paper we studied, the synthesis of CTAB capped ZnS NPs as well ZnS- L Cysteine: core-shell NPs and examined by their composition, particle size and optical and luminescent properties. The NPs stabilized with CTAB and demonstrated the regular ZnS blue emission on recombination over ZnS band-crevice from shallow electron traps at 490 nm. The onset of the absorption was 80 nm blue shifts moved from 345 nm (bulk) to 265 nm, showing a quantum size impact. Quantum mechanical effect of light applied especially in semiconducting NPs through optoelectronic orbital model, which detect and control the light through electronic devices.

Hepatotoxicity, nephrotoxicity, and drug/chemical interaction toxicity of platinum nanoparticles in mice.

Nanomaterials are frequently used in microelectronics, cosmetics, and sunscreens. Platinum reagents are commonly used in disease diagnosis, cosmetics, and the food industry. Although research into the development of nanomaterialbased drug delivery systems has yielded promising results, the toxicity of these materials is not fully understood. We investigated the toxicity and drug interactions of 1- and 8-nm diameter platinum nanoparticles (nPt1 and nPt8, respectively) in mice. Acute hepato-renal toxicity of intravenously administered platinum nanoparticles was evaluated biochemically and histologically. Dose-dependent increases in serum markers of hepato-renal function (serum aminotransferases and blood urea nitrogen) were observed following administration of nPt1, whereas nPt8 had no effect, even at 20 mg/kg. Moreover, nPt1 induced interleukin (IL)-6 and IL-1β production 3 and 6 hours after administration. The effect of nPts on drug-induced toxicity was evaluated in mice injected intraperitoneally with carbon tetrachloride or cisplatin, with or without intravenous administration of platinum nanoparticles. All treatments in the absence of nanoparticles were non-lethal and resulted in moderate toxicity. However, exacerbated toxicity was observed in mice injected with carbon tetrachloride or cisplatin together with nPt1, but not in mice co-injected with nPt8. We found that nPt1 cause hepato-renal damage, and the effect is enhanced by chemical inducers of hepatotoxicity and nephrotoxicity. This is the first report demonstrating that nPt1 not only are hepatotoxic and nephrotoxic but also exacerbate drug toxicity. These findings will be useful for future nanotechnology and nanoscience research.

The development and applications of &amp;lt;italic&amp;gt;in situ&amp;lt;/italic&amp;gt; liquid chamber TEM technologies

Transmission electron microscopy (TEM), with the high spatial and temporal resolution, is widely used in nano material characterizations. Due to the vacuum compatibility issue, traditional TEM is mostly used for solid and dry samples. The progress of nano science involves a wide range of liquid environments, and the development of in situ liquid chamber TEM technologies has made it possible for real time dynamic analysis on samples in liquid environments, with nanometer scale imaging resolutions, and greatly expanded the application ranges of TEM. This field has now brought much attention internationally, and is currently growing with a very rapid speed. In this paper, we review the progress about in situ liquid chamber TEM that our group has participated in and/or carried out in the recent years. It includes the development of the in situ liquid chamber TEM experiment apparatus, and its applications in the fields of nano-material preparations and characterizations, electrochemical reaction processes, new energy materials and devices, and life sciences. At last, the future development trend of in situ liquid chamber TEM is prospected. Firstly, some in situ liquid chamber TEM experiment apparatuses have been developed. These in situ chambers are home-made, based on metal cages and O-ring seals, which allow silicon nitride window substrates to be quickly assembled together, with liquid samples sealed inside. Besides simple imaging, electrochemical and heating-cooling functions have been incorporated into the setups, allowing for more advanced analyses. Using these in situ TEM apparatus, several nano material and reaction systems have been monitored. A sliver particle aqueous solution sample has been characterized. The particles were observed to be about 5–18 nm, attached to the Si3N4 windows, and could not be able to move freely in the liquid. Fine structures within single particles could be clearly seen. Bubbles commonly exist in an in situ liquid chamber, which are important for effectively reducing the local liquid layer thickness and enhancing the imaging resolution. In Au particle aqueous solution sample, particle and particle cluster motions have been further observed. The results show that particles in a cluster gradually fused together with time. For Au/AgCl composite nanocube sample, more dramatic electron beam effect has been seen, and the nanocubes were transformed quickly into hollow structures. By means of a liquid phase electron beam induced deposition (LP-EBID) approach, Si and SiC x nano structures have been made with in situ liquid chamber TEM. Nano dots, nano lines and three-dimensional nano structures can be controllably made by adjusting the electron beam exposure conditions. Secondary electron effects are attributed to the nano structural growth mechanism. Choosing Ni/NiCl2 system, both electrochemical deposition and etching of the nickel nano films have been observed by applying electric biases of different polarities to the nickel electrodes in the in situ chamber. Instead of extensional growth on existing crystals, it is more commonly observed that new nickel nano particles grow out in front of the existing film first and then merge into the film. During electrochemical etching, holes form in the Ni films due to Rayleigh instability. The structures of E. coli cells in aqueous solutions have been studied. Most of the cells remaine intact under the electron beam irradiation, Pili motions have been observed in the TEM imaging. Fluorescent imaging data confirm that the cells can keep alive after long time electron bean irradiation during the experiment. In situ liquid chamber TEM has opened up a new way for conducting research in nano science, new energy materials and devices, life sciences, involving liquid environments. In the future, it is expected that advanced functions of the in situ liquid chamber TEM will be further developed, and the application scope will be further expanded.

Does Size Matter? The Multipolar International Landscape of Nanoscience

How do different countries tackle nanoscience research? Are all countries similar except for a trivial size effect, as science is often assumed to be universal? Or does size dictate large differences, as large countries are able to develop activities in all directions of research, while small countries have to specialize in some specific niches? Alternatively, is size irrelevant, as all countries have followed different historical paths, leading to different patterns of specialisation? Here, we develop an original method that uses a bottom-up definition of scientific subfields to map the international structure of any scientific field. Our analysis shows that nanoscience research does not show a universal pattern of specialisation, homothetic of that of a single global leader (e.g., the United States). Instead, we find a multipolar world, with four main ways of doing nanosciences.

Transmission electron microscopy for nanomedicine: novel applications for long-established techniques.

During the last twenty years, the research in nanoscience and nanotechnology has dramatically increased and, in the last decade, the interest has progressively been oriented towards biomedical applications, giving rise to a new field termed nanomedicine. Transmission electron microscopy is a valuable technique not only for the thorough physico-chemical characterization of newly synthesized nanoparticulates, but especially to explore the effects of nanocomposites on biological systems, providing essential information for the development of efficient therapeutic and diagnostic strategies. Thus, for the progress of nanotechnology in the biomedical field, experts in cell biology, histochemistry and ultramicroscopy should always support the chemists, physicists and pharmacologists engaged in the synthesis and characterization of innovative nanoconstructs.

El riesgo nano en contexto. De cómo los investigadores en nanociencias manejan las incertidumbres

Nanotechnology is a set of knowledge, technical skills, and instruments that enable to manipulate nanoscale objects. Its applications could impact everyday life and, in many countries, it has been defined as a public policy priority since the beginning of the 2000’s. However, there remain uncertainties about health and environmental risks that are related to the use of nanotechnology. This text deals with the cognitive strategies and practices of researchers in nanoscience in order to deal with such uncertainties. Based on interviews conducted in Paris research centers, three directions of analysis are considered: 1) the permanence of a rationalist and linear model of risk evaluation and regulation that shapes boundaries between inside and outside the laboratory; 2) the contextualization and relativization of risks within the laboratory; and 3) the regulation of risks in the laboratory, via a set of institutional procedures that are mainly aligned with the risk management model of industrial hygiene.

Guest Editorial

Guest Editorial