Nano Electron Research Articles

Fabrication of nano-capillary emitter arrays for ionic liquid electrospray thrusters

In this study, we fabricated nano-capillary emitter arrays for stable ion emission of ionic liquid electrospray thrusters, employing the fabrication of field emitter arrays or gated nano electron sources. A nano-capillary emitter was successfully fabricated with a 100–300 nm capillary diameter, which prevented ionic liquid leakage by significantly increasing the fluidic impedance of the ionic liquid compared to a previously proposed emitter. An ion emission experiment was conducted with 1-ethyl-3-methylimidazolium dicyanamide as the propellant. Ion emission started at a low voltage of 61 V owing to a small gap of approximately 1 μm between the emitter and extractor electrode. The maximum current density was 43 mA cm−2 on the positive side and −13 mA cm−2 on the negative side without leakage of the ionic liquid, which was more than 100 times higher than that of conventional electrospray thrusters. Moreover, we obtained continuous ion emission without current intercepted by the extractor.

Comparative analysis of different extracellular vesicles secreted by Echinococcus granulosus protoscoleces

Extracellular vesicles (EVs) are heterogeneous populations of different membrane-wrapped vesicles in size and encapsulated cargo and have recently emerged as a crucial carrier with the functions in intercellular communication, being involved in host-parasite interactions. However, Echinococcus granulosus EVs are not fully described. To separate EVs with a different size, the culture supernatant of E. granulosus protoscoleces (PSCs) was sequentially centrifuged at 2,000g, 10,000g and 110,000g, and the resulting precipitates were accordingly named as 2K, 10K and 110K EVs, respectively. The size and morphology of three different EVs were identified using ZETASIZER NANO and transmission electron microscopy (TEM), respectively. Then mass spectrometry was applied to define protein cargo of EVs and EV internalization was assessed using fluorescent microscopy and flow cytometry. The results showed that 2K EVs mainly ranged from 450 to 950 nm in diameter, 10K EVs ranged from 220 to 390 nm and 110K EVs from 60 to 150 nm. A total of 901 EV proteins were identified, 328 of which were commonly found in the three types of EVs. GO analysis revealed that these proteins were mainly involved in binding (44%) and catalytic activity (44%). Three types of EVs were different in biomarkers (Enolase and 14-3-3) and in reactivity with anti-echinococcosis positive serum. Moreover, 110K EVs were more easily internalized by hepatic cells than 10K EVs as well as 2K EVs (p < 0.0001). These results reveal the physical and biological discrepancy among 2K, 10K and 110K EVs, suggesting a distinct role in host-parasite interactions.

Fabrication of a high-density emitter array for electrospray thrusters using field emitter array process

To improve the thrust density of electrospray thrusters using ionic liquids as the propellant, we have fabricated a high-density emitter array utilizing the fabrication technique of a field emitter array (FEA) or gated nano electron sources. The density of the emitter array can reach approximately 4 million cm−2, which is four orders of magnitude higher than that of conventional electrospray thrusters. Performing deep reactive ion etching from the back side of the same structure as FEAs and removing their Ni cones by dilute nitric acid, we have successfully fabricated sub-μm scale capillary emitters with self-aligned extractor electrodes and ionic liquid reservoirs behind them. Current measurements were also conducted with EMI-BF4 and EMI-DCA as the propellant. Although the ion was not extracted with EMI-BF4 owing to its electrochemical reaction with the electrodes, both positive and negative ion currents were detected using EMI-DCA, where the current density exceeded that of conventional electrospray thrusters.

MP54-15 UROTHELIAL BLADDER CANCER CELLS AFFECT TUMOR-PROMOTING PROCESSES IN NORMAL BLADDER FIBROBLASTS AND SUPPORT TUMORIGENESIS BY SECRETION OF TUMOR-ASSOCIATED EXOSOMES

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology I1 Apr 2018MP54-15 UROTHELIAL BLADDER CANCER CELLS AFFECT TUMOR-PROMOTING PROCESSES IN NORMAL BLADDER FIBROBLASTS AND SUPPORT TUMORIGENESIS BY SECRETION OF TUMOR-ASSOCIATED EXOSOMES Sophie Baumgart, Joana Heinzelmann, Elmar Krause, Marie Stampe-Ostenfeld, Michael Stöckle, and Kerstin Junker Sophie BaumgartSophie Baumgart More articles by this author , Joana HeinzelmannJoana Heinzelmann More articles by this author , Elmar KrauseElmar Krause More articles by this author , Marie Stampe-OstenfeldMarie Stampe-Ostenfeld More articles by this author , Michael StöckleMichael Stöckle More articles by this author , and Kerstin JunkerKerstin Junker More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.1706AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES MiRNAs packed in exosomes (EV) can affect cell-cell communication in the tumor microenvironment and play a crucial role in tumorigenesis. Our aim is the identification of a specific exosomal miRNA expression pattern depending on the invasiveness of urinary bladder cancer (BC) cells. Furthermore we want to characterize their functional role in reprogramming normal bladder fibroblasts (BF). METHODS EVs were isolated from invasive (T24,253J-BV,J82), non-invasive (RT112,5637) BC cells and normal bladder cells (HCV29) by ultracentrifugation and were characterized by Western Blot analysis, Nano Particle Tracking Analysis and electron microscopy. Uptake of PKH26-labeled BC-EV by hTERT-immortalized fibroblasts (hTERT-FB) was shown by LSM. EV-mediated miRNA transfer between BC cells and hTERT-FB was analyzed by transfection of BC cells with cel-miR-39, co-cultivation with hTERT-FB and qPCR. Proliferation and migration of EV-treated normal BF were measured by BrdU assay and Boyden Chamber assay. RESULTS Electron microscopy images revealed the typical size (61-81 nm) and vesicular structure of EV. Isolated EV exhibited a high amount of exosomal markers (CD81, syntenin) and less presence of contamination marker calreticulin. EV of invasive BC cells are characterized by a specific miRNA signature of 15 miRNAs. Validation of 6 selected miRNAs confirms a significant different expression between both, invasive and non-invasive cells and their EV. miR-30a-3p could be confirmed by qPCR to be significantly deregulated exclusively in EVs of invasive cells compared to the non-invasive counterparts, but not in the parental cells. Uptake of labeled EV and exosomal miRNA of BC cells in hTERT-FB could be confirmed. Co-cultivation of tumor-associated and normal EV and normal BF resulted in increased proliferation and migration rates in normal BF independently from the invasiveness of donor BC cells, but cell-type specific. CONCLUSIONS EVs secreted by BC cells are characterized by a specific miRNA pattern depending on their invasiveness. We demonstrated that tumor-derived EV can stimulate the proliferation and migration of BF indicating an important role in cell-cell communication. Further studies have to investigate the changes of signaling pathways in fibroblasts induced by EV and their miRNAs and the role in the development of an invasive phenotype. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e717-e718 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Sophie Baumgart More articles by this author Joana Heinzelmann More articles by this author Elmar Krause More articles by this author Marie Stampe-Ostenfeld More articles by this author Michael Stöckle More articles by this author Kerstin Junker More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

MP45-01 EXOSOMAL MIRNAS: KEY REGULATORS OF CELL-CELL COMMUNICATION BETWEEN BLADDER CANCER CELLS AND TUMOR MICROENVIRONMENT

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology I1 Apr 2016MP45-01 EXOSOMAL MIRNAS: KEY REGULATORS OF CELL-CELL COMMUNICATION BETWEEN BLADDER CANCER CELLS AND TUMOR MICROENVIRONMENT Sophie Baumgart, Joana Heinzelmann, Elmar Krause, Marie Stampe Ostenfeld, Arndt Hartmann, Michael Stöckle, and Kerstin Junker Sophie BaumgartSophie Baumgart More articles by this author , Joana HeinzelmannJoana Heinzelmann More articles by this author , Elmar KrauseElmar Krause More articles by this author , Marie Stampe OstenfeldMarie Stampe Ostenfeld More articles by this author , Arndt HartmannArndt Hartmann More articles by this author , Michael StöckleMichael Stöckle More articles by this author , and Kerstin JunkerKerstin Junker More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.278AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Interaction of tumor cells and tumor microenvironment (TME) plays an important role in tumor progression. It was shown that microRNAs (miRNAs) packed in exosomes (EV) can affect cell-cell communication at the site of origin (TME) as well as distant sites. One aim of the project is the identification of a specific miRNA expression pattern from tumor-derived EV of different urinary bladder cancer (UBC) cell lines in correlation to their invasive potential. Afterwards, the functional role of specific exosomal miRNAs on cells of the TME (e.g. naive fibroblasts) will be analyzed. METHODS EV were isolated from invasive (T-24,253J-BV, J82) and non-invasive (RT-112, 5637) UBC cell lines and characterized by Western Blot analysis, Nano Particle Tracking Analysis and electron microscopy. MiRNA expression analysis in UBC cells and their EV was performed by using miRNA microarray and qPCR. Uptake of PKH26-labeled UBC-EV by immortalized fibroblasts was shown by laser scanning microscopy. EV-mediated miRNA transfer between cancer cells and fibroblasts was verified by transfection of donor UBC cells with the C. elegans-specific miRNA, cel-miR-39, EV isolation and RNAse treatment, transfer to recipient fibroblasts (TAFs and naive fibroblasts), and miRNA-specific qPCR analysis using totalRNA from the recipient fibroblasts. RESULTS Electron microscopy images revealed the typical size and vesicular structure of EV. The size measurement revealed a mean size of EV among 61-81nm. Isolated EV exhibited a high amount of exosomal markers (CD81, syntenin) and less presence of contamination marker calreticulin. 16 miRNAs were identified distinguishing invasive UBC cells from non-invasive cells. EV secreted by invasive UBC cells are characterized by a specific miRNA signature of 25 miRNAs compared to EV from non-invasive UBC cells. 6 significantly different expressed miRNAs clearly separate both invasive and non-invasive UBC cells and their secreted EV. Labeled EV of UBC cells were taken up by naive fibroblasts. After co-cultivation of EV obtained from transfected UBC cells and naive fibroblasts, high expression of cel-miR-39 was detected in naive fibroblasts. CONCLUSIONS EV secreted by UBC cells exhibit a specific miRNA signature depending on the invasive potential of the originating cells. For the first time we demonstrated the EV-mediated transfer of miRNAs between UBC cells and naive fibroblasts. Furthermore, EV of UBC cells can be taken up by fibroblasts. These results emphasize the role of exosomal miRNAs for the interaction between tumor cells and the tumor microenvironment. Further studies have to show the functional relevance of selected exosomal miRNAs. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e607 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Sophie Baumgart More articles by this author Joana Heinzelmann More articles by this author Elmar Krause More articles by this author Marie Stampe Ostenfeld More articles by this author Arndt Hartmann More articles by this author Michael Stöckle More articles by this author Kerstin Junker More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Development of antibacterial cellulosic fabric via clean impregnation of silver nanoparticles

In the present study, we investigate single bath fabrication and impregnation of silver nanoparticles (SNPs) on enzymatic pretreated cotton fabric by using starch both as reducing as well as stabilizing agent under the autoclave conditions of 103.42 kPa, 121 °C for 15 min. The SNPs were characterized using UV–visible (UV–vis) spectroscopy, zetasizer nano and transmission electron microscopy. The UV–vis absorption spectra showed typical absorption peaks at ∼420 nm corresponding to the surface plasmon resonance of SNPs. The hydrodynamic diameter of SNPs was as smaller as 20 nm with their respective zeta potential of −43.20 mV. Both scanning electron and atomic force microscopic analyses revealed that the surface of the treated cotton fabric was rougher than that of untreated fabric, and the SNPs were present on the surface of the treated fabric. Silver mapping and elemental analysis of the treated cotton fabric using energy dispersive X-ray spectroscopy confirmed the presence of SNPs in a homogeneous distribution. The textile properties of the fabric including wettability, whiteness, tensile strength and antibacterial activity were measured by using the standard methods. The SNPs impregnated cotton fabrics showed good durable antibacterial activity against Escherichia coli and Staphylococcus aureus strains.

Electron and X-ray diffraction – two worlds united

Small crystals structure solution usually done with X-ray powder diffraction (XRPD) provides bulk information and is powerful for in-situ investigations. Peak overlap in the one-dimensional data causes problems e.g. for polyphasic or impure samples and large cell parameters thus peak indexing and intensity extraction are the main issues where x-ray powder data may be supported by extra information. Electrons sample smaller volumes but strong coulombic interaction cause multiple scattering effects changing intensities often so strong that a structure solution is becoming impossible. Nevertheless, oriented electron diffraction patterns may provide sufficient information to support indexing or the assignment of impurity peaks in the case of low quality x-ray powder pattern. Reciprocal space tomography [1] uses a series of non-oriented diffraction patterns for which dynamical effects are significantly reduced and an enhanced amount of independent reflections sampled allows "ab-initio" crystal structure solution using established X-ray structure solution packages. Although structure refinement based on kinematical intensities is stable, achievable R values of 10-30% are high and final refinement may be performed based on X-ray powder data. Scanning transmission electron microscopy (STEM) for crystal tracking and nano electron diffraction (NED) is suitable for beam sensitive material, agglomerated particles, twins or intergrown phases on crystals down to 30nm size [2, 3]. Interesting properties of nanocrystalline materials are driven mainly by twinning, defects, disorder in one or two dimensions down to the amorphous state. Here low data completeness or uncertain intensity determination causes problems in structure solution. Here a mean structure may be determinable serving as a basis for disorder description and being used as a starting model being refined onto X-ray powder data maybe supported by a combination of the diffraction methods or by adding extra information.

Determination of elemental distribution in green micro-algae using synchrotron radiation nano X-ray fluorescence (SR-nXRF) and electron microscopy techniques – subcellular localization and quantitative imaging of silver and cobalt uptake by Coccomyxa actinabiotis

The newly discovered unicellular micro-alga Coccomyxa actinabiotis proves to be highly radio-tolerant and strongly concentrates radionuclides, as well as large amounts of toxic metals. This study helps in the understanding of the mechanisms involved in the accumulation and detoxification of silver and cobalt. Elemental distribution inside Coccomyxa actinabiotis cells was determined using synchrotron nano X-ray fluorescence spectroscopy at the ID22 nano fluorescence imaging beamline of the European Synchrotron Radiation Facility. The high resolution and high sensitivity of this technique enabled the assessment of elemental associations and exclusions in subcellular micro-algae compartments. A quantitative treatment of the scans was implemented to yield absolute concentrations of each endogenous and exogenous element with a spatial resolution of 100 nm and compared to the macroscopic content in cobalt and silver determined using inductively coupled plasma-mass spectrometry. The nano X-ray fluorescence imaging was complemented by transmission electron microscopy coupled to X-ray microanalysis (TEM-EDS), yielding differential silver distribution in the cell wall, cytosol, nucleus, chloroplast and mitochondria with unique resolution. The analysis of endogenous elements in control cells revealed that iron had a unique distribution; zinc, potassium, manganese, molybdenum, and phosphate had their maxima co-localized in the same area; and sulfur, copper and chlorine were almost homogeneously distributed among the whole cell. The subcellular distribution and quantification of cobalt and silver in micro-alga, assessed after controlled exposure to various concentrations, revealed that exogenous metals were mainly sequestered inside the cell rather than on mucilage or the cell wall, with preferential compartmentalization. Cobalt was homogeneously distributed outside of the chloroplast. Silver was localized in the cytosol at low concentration and in the whole cell excluding the nucleus at high concentration. Exposure to low concentrations of cobalt or silver did not alter the localization nor the concentration of endogenous elements within the cells. To our knowledge, this is the first report on element co-localization and segregation at the sub-cellular level in micro-algae by means of synchrotron nano X-ray fluorescence spectroscopy.

Observation of fringelike electron emission pattern from triode Pt nano electron source fabricated by electron-beam-induced deposition

A triode Pt nano electron source with a gate electrode to control the intensity of fringelike emission pattern with low gate voltage has been fabricated. Characteristics of the triode Pt nano electron source were measured at room temperature in a vacuum of less than 10−7 Pa. The emission current was observed when the gate voltage was higher than 30 V and showed a linear dependence in the Fowler–Nordheim plot. Electron wave interference patterns from the triode Pt nano electron source were first observed. The intensity of the electron wave interference pattern was successfully controlled by the gate voltage up to 50 V.

Thermal and thermo‐oxidative degradation study of a model LDPE/EVA based TPE system: Effect of nano silica and electron beam irradiation

AbstractThe effect of nano‐silica on the thermal degradation behavior of Low density polyethylene‐poly(ethylene‐ co‐vinyl acetate) (LDPE‐EVA) based thermoplastic elastomeric (TPE) system was monitored using thermo gravimetric analysis (TGA) in nitrogen and oxygen atmospheres (air), respectively. The pristine nano silica was melt‐blended with the LDPE‐EVA system at different loadings by varying the sequence of addition. In one of the compositions, coupling agent (Si69) was used. In nitrogen, thermal stability of such systems remained unchanged. However, in oxygen atmosphere, the TGA thermograms reflected a dramatic change. A two staged degradation was observed for all the samples. The enhancement in thermal stability particularly upto the low conversion levels was interpreted in terms of the barrier effect of silica particles on the O2 flow into the sample. The activation energies of degradation up to lower range of conversions were determined by nonisothermal and isothermal kinetic analyses. These were found to register a similar trend for various systems studied. Upon electron beam irradiation of such filled LDPE/EVA systems at controlled doses (20 and 40 kGy), the thermal stabilities were enhanced marginally. Overall, the thermal stabilities of the TPE nanocomposites are the function of sequence and extent of nano silica addition, presence of coupling agent and extent of irradiation. POLYM. COMPOS., 31:1387–1397, 2010. © 2009 Society of Plastics Engineers

Automated diffraction tomography combined with electron precession: a new tool forab initionanostructure analysis

AbstractThree-dimensional electron diffraction data was collected with our recently developed module for automated diffraction tomography and used to solve inorganic as well as organic crystal structuresab initio. The diffraction data, which covers nearly the full relevant reciprocal space, was collected in the standard nano electron diffraction mode as well as in combination with the precession technique and was subsequently processed with a newly developed automated diffraction analysis and processing software package. Non-precessed data turned out to be sufficient forab initiostructure solution by direct methods for simple crystal structures only, while precessed data allowed structure solution and refinement in all of the studied cases.

Characteristics of nano electron source fabricated using beam assisted process

A nano electron source was fabricated using electron beam-induced deposition. Characteristics of a nano electron source fabricated using beam assisted processes were investigated by current–voltage measurement. The emission current was observed at a gate voltage of 25 V and showed a linear dependence in Fowler–Nordheim plots. An emission half-angle of about 9.8° was obtained.

Transmission Electron Microscopy Study of Y2O3 Nanotips Grown on LaAlO3

Y2O3 is a super refractory oxide with high thermal stability and finds various applications in optics and microelectronic devices. Recently, Eu-activated Y2O3 films attracted much research interest due to its promising applications in flat panel field emission displays. Epitaxial Y2O3:Eu thin films have been grown on LaA1O3(LAO). in this paper we report a transmission electron microscopy (TEM) study of Y2O3 nano tip-structure grown on LAO by pulsed laser deposition using stoichiometric YBa2Cu3O7-σ.a target under a low oxygen pressure. The experimental work was conducted within a JEOL2010F TEM equipped with an ED AX system.Fig.l is a low magnification cross-section TEM image of the nano-tip structure grown on (001) LAO. The lattice parameters of the tips were calculated to be that of Y2O3 by using LAO as a standard for indexing the diffraction patterns. Nano electron beam diffraction patterns from the tips along [100] and [110] axis are shown in Fig.2a and Fig.2b, respectively, in agreement with the simulated ones using bulk Y2O3 structure.

On Crystal Structure of a Pseudo-Equilibrium Phase in β′-NiAl

Non-stoichiometric β'-NiAl alloys annealed at 623 K show a tweed pattern in a bright-field image and streaks follow diffuse intensity maxima at {1/6 1/6 0} along in a diffraction pattern. These characteristics can be clearly observed at a thin part of the foil specimen and suggest formation of a pseudo-equilibrium phase in β'-NiAl. The crystal structure of the pseudo-equilibrium phase was studied using a high resolution electron microscope and an analytical electron microscope with a nano electron probe. Black and white bands along with about 10 nm width appear at an extremely thin part of the wedge-shape specimen. A lattice image of the black band is quite different from that of β'-NiAl. The diffraction pattern reveals that the thin region including the black and the white band consists of β'-NiAl, Ni 2 Al 3 , and Ni 3 Al 2 . Element analysis by EDX shows that a concentration ratio of Ni and Al at the black band is about 3/2. Therefore, it can be concluded that Ni 3 Al 2 phase is formed there