TY - CONF A1 - Schmidt, Wolfram T1 - Influence of nano scale effects on the macroscopic rheology N2 - Chemical admixtures like superplasticisers or stabilising agents are of ever increasing importance for modern concrete technology. They liberate the workability of concrete from its dependency on water content, and thus, open the gate towards innovative and future oriented concrete technologies. Meanwhile admixtures have become common practice in concrete technology, but the understanding of these highly complex polymers in the entire concrete system lags far behind their application. Due to its complex time-dependent, multi-phase and multi-scale behaviour, flowable concrete systems are highly complicated and cannot be described comprehensively by simple models. It is therefore extremely challenging to identify the relevant parameters that predominantly control flow phenomena on different size scales, since these may occur on any scale between the nano scale (e.g. superplasticizer adsorption) and macro scale (e.g. grading of the aggregates). The present study discusses fundamental mechanisms at the interface between particle or hydrate surfaces and the fluid phase at a very early stage of concrete formation, and links these effects to macroscopic flow phenomena. Based on the observations of the nano scale effects, it seems that higher sensitivity against variations in the constituents, the handling, or the boundary condition are the inevitable price for higher performances. However, eventually a very effective method is introduced that helps to maintain stable processes regardless of the root cause for performance changes based on an efficient in-situ process control scheme and superplasticizer and stabilising agents as counter actions. T2 - International Workshop on Nano-Engineered Meta-materials for Civil Infrastructures CY - Jinan, China DA - 20.5.2017 KW - Rheology KW - Meta materials KW - Nano engineering KW - Admixtures KW - Cement KW - Ettringite PY - 2017 AN - OPUS4-41032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlegel, Moritz-Caspar T1 - Nano-porous Materials - Introduction into Metal-organic Frameworks N2 - Metallic organic frameworks are the materials stirring great interest by their large variety of structure types and chemical composition as well as low density and very high surface area, which are desirable properties for gas storage such as for hydrogen, methane or carbon dioxide. Using different so called secondary building units offer an opportunity to form tunable structures with channels of various geometry and allow in this way to study the absorption of the molecular hydrogen, methane or carbon dioxid in the systematic way. T2 - Neutron Scattering Application to Hydrogen Storage Materials CY - Berlin, Germany DA - 07.08.2017 KW - MOFs KW - Hydrogen KW - Crystallography PY - 2017 AN - OPUS4-41285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Harald A1 - Unger, Wolfgang A1 - Schulte, Petra A1 - Hodoroaba, Vasile-Dan T1 - Nanotechnologie Aktivitäten der BAM N2 - Die Präsentation gibt einen Überblick über die verschiedenen Aktivitäten der BAM im Bereich der Nanotechnologie mit den Schwerpunkten Nanopartikel und Nanosicherheit. Es wird sowohl die Transportsicherheit, als auch die Sicherheit von Batterien mit Nanopartikeln angesprochen. Verschiedene BAM-Projekte zum Thema Nano werden vorgestellt, beginnend mit relevanten REFOPlanprojekten über die Erstellung der OECD nanoTG110 bis hin zu EU-Projekten zur Standardisierung von Messungen an Nanomaterialien, hier insbesondere AEROMET, NanoDefine, NanoValid und EC4SafeNano. T2 - Nano-Behördenklausur der Bundesoberbehörden CY - Berlin, Germany DA - 02.11.2017 KW - Nano KW - Nanotechnologie KW - Nanopartikel KW - Nanosicherheit KW - Nanoanalytik PY - 2017 AN - OPUS4-42793 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rauscher, H. T1 - Role of the volume specific surface area in the NanoDefine decision flow scheme N2 - In this lecture the VSSA concept is explained, and VSSA as measured by BET. Results of the NanoDefine evaluation based on selected examples on real-world materials are presented. Recommendations for consideration of the VSSA concept for the implementation of the EC definition of nanomaterial for powder materials are given. T2 - Final Outreach Event “Classification of nanomaterials according to the EU definition” CY - Brüssel, Belgium DA - 19.09.2017 KW - Volume specific surface area (VSSA) KW - Nanomaterial KW - Nanomaterial classification KW - BET PY - 2017 AN - OPUS4-42391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kästner, B. A1 - Vogel, Christian A1 - Hermann, P. A1 - Adamczyk, Burkart A1 - Hoehl, A. A1 - Ulm, G. A1 - Adam, Christian T1 - Synchrotron radiation-based nano-FTIR spectroscopy for the characterization of chlorine gas corrosion of different silicon carbides N2 - Near-field optical techniques such as nano-FTIR spectroscopy enable spectroscopic characterization of samples with a high sensitivity and a spatial resolution at the nanoscale. In this work we realized nano-FTIR spectroscopy by elastic scattering of infrared light from a probe tip of an atomic force microscope operated in tapping mode, with broadband infrared synchrotron radiation provided by the Metrology Light Source (MLS). We apply this technique to characterize the protective oxidation layers of different Silicon Carbides (SiCs) treated by chlorine gas. The process using chlorine-donors has been developed to separate toxic heavy metals from sewage sludge ash (SSA) and to increase the plant-availability of phosphors in the SSA in order to produce P-fertilizers. Nitrified SiC showed the highest resistant strength against chlorine corrosion at 1000 °C compared to the other SiCs. In order to discuss this behavior high resolution imaging has been performed on the interfacial layer between bulk-SiC and the protective oxidation layer on sub-micrometer scale. The formation of a SixNiyO protective layer, which might be the reason for the higher corrosion resistance, was observed using nano-FTIR spectroscopy. T2 - WIRMS2017 CY - Oxford, UK DA - 25.09.2017 KW - Phosphorus recovery KW - Corrosion science KW - Nano-FTIR spectroscopy PY - 2017 AN - OPUS4-42450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Analysis of TiO2 nanoparticles – Various activities at BAM N2 - The presentation goes into the characterization of TiO2 engineered nanoparticles within EU/FP7 SETNanoMetro Project and the nanomaterial classification according to the EC definition tested within EU/FP7 NanoDefine Project. Further, ISO/TC 229/JWG 2 activities related on ISO standards in development and inter-laboratory comparisons on measurement of nanoparticle size and shape distribution by SEM and TEM are discussed. T2 - Seminar CY - PTB Braunschweig, Germany DA - 23.03.2017 KW - Nanoparticles KW - Electron microscopy KW - Nanomaterial KW - Standardization KW - Inter-laboratory comparison PY - 2017 AN - OPUS4-39527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Advanced methods for nanomaterial characterization N2 - At the Final Outreach Event of the European FP7 NanoDefine project the results achieved during 4 years of intensive research and development work (2013-2017) with relevant stakeholders and wider community, and their practical implications and impact are presented and discussed. The newly developed particle-size related measurement tools and their practical suitability and applicability to classify materials, formulations and products according to the EC recommendation on the definition of a nanomaterial (2011/696/EU) are demonstrated. T2 - Final Outreach Event “Classification of nanomaterials according to the EU definition” CY - Brüssel, Belgium DA - 19.09.2017 KW - Nanomaterial KW - Nanoparticles KW - Particle sizing techniques KW - Nanomaterial classification PY - 2017 AN - OPUS4-42390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Available particle-sizing techniques at work for the classification as a nanomaterial - How reliable it really is? N2 - The capability of currently available particle sizing techniques for reliable classification of materials that potentially fall under the EU Definition of a nanomaterial is discussed. A systematic quantitative evaluation of the sizing techniques is presented together with representative case studies of analysis of industrially relevant materials. Recommendations on the most appropriate and efficient use of techniques for different types of material are given. T2 - Frontiers of Nanomaterial Characterization CY - Tokyo, Japan DA - 28.05.2017 KW - Nanomaterial classification KW - Nanoparticles KW - Number-weighted median size KW - Particle size analysis KW - Characterization techniques PY - 2017 AN - OPUS4-40474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - NanoDefine – a brief overview N2 - The large European nanometrology Project NanoDefine is presented briefly with respect to the challenges of measurement of particle size distribution for complex nanoparticulate materials. The methods chosen for a tiered approach for the classification of a nanomaterial are discussed with regard to their peformance. Representative resuls on real life, complex shaped nanoparticulate materials are shown. The recently initiated VAMAS inter-laboratory comparisons to determine the reproducibility necessary for international standardisation have been also presented. T2 - Metrology Study Group of ISO/TC 229 Nanotechnologies /JWG2 'Measurement and Characterization' CY - Tokyo, Japan DA - 31.05.2017 KW - EU definition of a nanomaterial KW - Nanomaterial classification KW - Nanoparticles KW - Nanoparticle size distribution KW - VAMAS inter-laboratory comparison KW - Particle sizing techniques PY - 2017 AN - OPUS4-40475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Harald A1 - Schmidt, Alexandra A1 - Bachmann, V. A1 - Kuhlbusch, T. T1 - Projekt Nano-TG110 N2 - Die OECD-TG110 mit dem Titel "Particle Size Distribution Fibre Length and Diameter Distribution" wurde 1981 erstellt und seither nicht überarbeitet. Nanomaterialien, wie Nanopartikel oder Nanofasern werden nicht adressiert, genausowenig wie moderne Messverfahren. Das hier vorgestellte Projekt hat zur Aufgabe, die Größenmessung von Nanopartikeln und Nanofasern in einer neuen Technical Guideline der OECD zu standardisieren. Es wird die Projekthistorie dargestellt, die Anforderungen, der aktuelle Projekt-Bearbeitungsstand wird beleuchtet und die weiteren Arbeiten werden kurz skizziert. T2 - Nano-Behördenklausur der Bundesoberbehörden CY - Berlin, Germany DA - 02.11.2017 KW - Nano KW - Nanopartikel KW - Nanoparticle KW - OECD KW - Guideline PY - 2017 AN - OPUS4-42737 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wäsche, Rolf A1 - Steinborn, Gabriele A1 - Woydt, Mathias T1 - Colloidal processing of Nbc cermets with Ni binder N2 - Niobium-titanium carbide cermets with nickel binder have been prepared by colloidal processing in water without a milling step by using Poly-diallyl-dimethyl-ammonium chloride (Poly-DADMAC) as a dispersant. Homogeneous microstructures with relative densities larger than 99% of the theoretical density have been achieved by gas pressure sintering in argon atmosphere. However, mechanical properties like hardness and strength were slightly decreased due to precipitation of free carbon. T2 - ISNT2017 & ISSNOX5 - 9th International Symposium on Nitrides & 5th International Symposium on SiAlONS and Non-Oxides CY - Sapporo, Japan DA - 27.08.2017 KW - Niobium carbide KW - Colloidal processing KW - Nckel binder KW - Hardness PY - 2017 AN - OPUS4-42152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele A1 - Wäsche, Rolf A1 - Woydt, Mathias A1 - Rabe, Torsten T1 - Improved wear resistant ceramics of metal incorporated NbC processed with gas pressure sintering N2 - Tungsten carbide (WC) dominates wear protection and machining since more than 90 years due to its hardness with an associated good toughness and high melting point. It was recently demonstrated that Niobium Carbides are wear resistant and show a better performing under cutting than WC grades. In order to profit of the good properties of Niobium Carbide, specific processing techniques need to be developed. The density of NbC is half of WC and offers colloidal processing for perfectly mixing NbC with metallic binder (up to 15 vol.-% Ni) and secondary carbide-particles. The used NbC-powder has an average particle size d50 of 3 micron measured by laser granulometry analysis. The true density was 7.68 g/cm3. An Oxygen content of the used NbC of 0.4 % is caused by residual slag content. It is possible to increase the stability of the NbC-suspensions and to reduce their viscosity by adding a specific dispersing agent. This surface-modified NbC powders (containing Ni)were uniaxially pressed and then gas pressure sintered in vacuum or Argon atmosphere. All samples reached more then 98 % of there theoretical density. The micrographs showed a homogenius distribution of the Ni-binder in the product. The tribological behaviour under dry sliding and oscillating up to 600 °C and the mechanical properties were studied. T2 - 92. Jahrestagung der Deutschen Keramischen Gesellschaft CY - Berlin, Germany DA - 19.03.2017 KW - NbC KW - Wear resistant KW - Gas pressure sintering PY - 2017 AN - OPUS4-40242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Elert, Anna Maria T1 - Application of NanoIR interdisciplinary research at BAM N2 - Atomic force microscopy based Infrared spectroscopy (AFM-IR) is a quickly evolving technique that provides chemical analysis and compositional mapping with spatial resolution far below conventional optical diffraction limits. This is possible since the detection method is based on a very sharp AFM tip which starts to oscillate when the sample starts to thermally expand (the changed is caused by the absorption of IR wavelength) where the thermal expansion is related to the IR absorption. This presentation briefly described the application of that new technique from polymer characterization and utilization of AFM-IR in material research, up to life science applications. T2 - AFM-IR Workshop: Nanoscale IR Spectroscopy CY - Dresden, Germany DA - 29.11.2017 KW - NanoIR KW - AFM KW - Composite KW - Polyurethane PY - 2017 AN - OPUS4-43221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem T1 - Nanotechnology at BAM N2 - The presentation gives a brief summary of the research activities of BAM in the field of nanotechnology. It was held at INERIS in the frame of a delegation meeting to identify topics for future collaborations. T2 - Kooperationstreffen mit INERIS CY - Verneuil-en-Halatte, France DA - 23.10.2017 KW - Nanotechnology KW - Nano Referenzmaterialien KW - Nanosafety PY - 2017 AN - OPUS4-43408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Triwikantoro, A1 - Bäßler, Ralph A1 - Aristia, Gabriela A1 - Putry, A. L. A1 - Santoso, E. T1 - The corrosion of PANI/SiO2 composite in synthetic geothermal atmosphere N2 - An extraction of silica from natural sands of Bancar has been conducted by means of alkali fusion route using NaOH and mechanical alloying using planetary ball milling. The PANI/SiO2 Composite system has been coated in steel surfaces using spraying method. This study was designed to obtain PANI/SiO2 as an anti-corrosion coating material. The filler materials in the composite System consist of micro- and nano-SiO2. The structure of synthesized SiO2 be characterized using XRD and TEM. Corrosion of PANI/SiO2 composite has been tested using immersion method in synthetic geothermal atmosphere (Nord Deutsche Becken/NDB solution). The surface morphology after corrosion was observed by using SEM/EDX. XRD-Patterns and TEM show that the size of produced SiO2 is micro and nano. The size and composition of filler have influenced to surface degradation in geothermal atmosphere significantly. The addition of nano-SiO2 in the PANI matrix influenced corrosion resistance better than micro-SiO2 filler qualitatively. The nano-SiO2 has a high potential as an anti-corrosion material in geothermal atmosphere. The product of corrosion is mainly Fe2O3 and the corrosion process is identified as a pitting corrosion. T2 - The 7th Nanoscience and Nanotechnology Symposium CY - Bandung, Indonesia DA - 22.10.2017 KW - Composite KW - PANi/SiO2 KW - Anti-Corrosion PY - 2017 AN - OPUS4-43275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Phenotypic diversity in microbial metabolism and antimicrobial resistance N2 - Most microorganisms live in environments where nutrients are limited and fluctuate over time. Cells respond to nutrient fluctuations by sensing and adapting their physiological state. Recent studies suggest phenotypic heterogeneity in isogenic populations as an alternative strategy in fluctuating environments, where a subpopulation of cells express a function that allows growth under conditions that might arise in the future. It is unknown how environmental factors such as nutrient limitation shape phenotypic heterogeneity in metabolism and whether this allows cells to respond to nutrient fluctuations. Here, we show that substrate limitation increases phenotypic heterogeneity in metabolism, and this heterogeneity allows cells to cope with substrate fluctuations. We subjected the N2-fixing bacterium Klebsiella oxytoca to different levels of substrate limitation and substrate shifts, and obtained time-resolved single-cell measurements of metabolic activities using nanometre-scale secondary ion mass spectrometry (NanoSIMS). We found that the level of NH4+ limitation shapes phenotypic heterogeneity in N2 fixation. In turn, the N2 fixation rate of single cells during NH4+ limitation correlates positively with their growth rate after a shift to NH4+ depletion, experimentally demonstrating the benefit of heterogeneity. The results indicate that phenotypic heterogeneity is a general solution to two important ecological challenges - nutrient limitation and fluctuations - that many microorganisms face. Currently, we use NanoSIMS to develop a new approach that defines functionally-relevant, phenotypic biodiversity in microbial systems. In the last part of my presentation, I will highlight why the concept of phenotypic diversity is relevant for the understanding of antimicrobial resistance. T2 - Seminars in Evolution and Ecology at FU Berlin CY - Berlin, Germany DA - 06.11.2017 KW - Antimicrobial Resistance KW - Metabolism KW - Phenotypic diversity PY - 2017 AN - OPUS4-42915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Dietrich, Paul A1 - Fischer, Tobias A1 - Rurack, Knut A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry N2 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry An increasing field of application, e.g. in biotechnology is the dedicated adjustment of surface properties by functionalization with organic molecules. For a detailed understanding and further development of such nano-layers, a quantitative determination of the surface density of molecular species is required. By means of reference-free X-Ray Fluorescence (XRF) spectrometry such surfaces can be analyzed quantitatively by detecting specific marker elements. Using calibrated instrumentation and a quantification approach based on atomic fundamental parameters a SI-traceable quantitative analysis without any calibration sample or reference material is possible. A chemical analysis of molecular bonds can be accomplished by X-Ray Absorption Spectroscopy in the Near-Edge region (NEXAFS). Especially in the soft X-ray range an access to relevant light elements like Carbon C, Nitrogen N and Oxygen is possible. Here, aminated surfaces with varying densities of amino groups prepared from binary mixtures of silanes were investigated. In a complementary analysis by X-Ray Photoelectron Spectroscopy (XPS) and Fluorescence measurements based on laser-excitation in the optical light spectrum the functional-group density of silane monolayers were determined. The nitrogen atom in the head-group of the silane-molecule could be used as specific marker for the reference-free quantitative XRF analysis and were used for traceable calibration of XPS and Fluorescence Spectroscopy. T2 - EMRS Spring Meeting 2017, ALTECH 2017, Symposium S, Analytical techniques for precise characterization of nano materials CY - Strasbourg, France DA - 22.05.2017 KW - XPS KW - XRF KW - Amino silane film KW - Traceability PY - 2017 AN - OPUS4-43374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Metrology for spatially resolved chemical analysis at the micro and nanometre scales - Surface analysis working group (SAWG) - Report for 15th meeting (2016/17) N2 - CCQM has established a framework of comparisons to demonstrate the international comparability of chemical measurements. The key point is the establishment of comparable measurements, with traceability to internationally or nationally stated references. Originally initiated by Dr Martin P Seah, NPL, the Surface Analysis Working Group (SAWG) has been formally founded in 2003. The following terms of reference were presented to CCQM in April 2002. CCQM ratified the group as a full working group of CCQM in April 2003 with these terms of reference: - to develop pilot studies and carry out key comparisons of national measurement standards for surface and micro/nano-analysis; - to assist in identifying and establishing inter-laboratory work to improve the traceability of surface and micro/nano-analysis; - to establish and update a work plan to be adopted by CCQM; - to discuss and review the scope of the working group and to liase with other working groups related to nanotechnology. Following the 2016 meeting, the Key Comparison K-129 "Measurement of atomic fractions in Cu(In,Ga)Se2 Films" lead by KRISS and the Key Comparison K-136 on "BET specific surface area of nanoporous Al2O3" lead by UNIIM&BAM have been finished in 2016. The 15th meeting of SAWG will focus on - survey on CMC claim submitted with reference to K-129 and K-136. - the overall and SAWG specific aspects of the CCQM Strategy process, - a joint meeting with the Inorganic Working Group addressing number concentrations of nano particles, - discussion of future comparisons. T2 - CCQM Plenary Meeting at BIPM 2017 CY - Paris, France DA - 27.4.17 KW - Metrology KW - Comparisons KW - CCQM PY - 2017 AN - OPUS4-40277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Phenotypic diversity in microbial metabolism N2 - Question: Most microorganisms live in environments where nutrients are limited and fluctuate over time. Cells respond to nutrient fluctuations by sensing and adapting their physiological state. Recent studies suggest phenotypic heterogeneity in isogenic populations as an alternative strategy in fluctuating environments, where a subpopulation of cells express a function that allows growth under conditions that might arise in the future. It is unknown how environmental factors such as nutrient limitation shape phenotypic heterogeneity in metabolism and whether this allows cells to respond to nutrient fluctuations. Methods: We subjected the N2-fixing bacterium Klebsiella oxytoca to different levels of substrate limitation and substrate shifts, and obtained time-resolved single-cell measurements of metabolic activities using nanometre-scale secondary ion mass spectrometry (NanoSIMS). Results: We show that substrate limitation increases phenotypic heterogeneity in metabolism, and this heterogeneity allows cells to cope with substrate fluctuations [1]. We found that the level of NH4+ limitation shapes phenotypic heterogeneity in N2 fixation. In turn, the N2 fixation rate of single cells during NH4+ limitation correlates positively with their growth rate after a shift to NH4+ depletion, experimentally demonstrating the benefit of heterogeneity. Conclusion: The results indicate that phenotypic heterogeneity is a general solution to two important ecological challenges—nutrient limitation and fluctuations—that many microorganisms face. Currently, we use NanoSIMS to develop a new approach that defines functionally-relevant, phenotypic biodiversity in microbial systems. T2 - MICROBIOLOGY AND INFECTION 2017 - 5th Joint Conference of the DGHM & VAAM - VAAM Annual Meeting 2017 - 69th Annual Meeting of the DGHM CY - Würzburg, Germany DA - 05.03.2017 KW - Phenotypic diversity KW - metabolism KW - NanoSIMS PY - 2017 AN - OPUS4-40782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kästner, Claudia A1 - Böhmert, L. A1 - Lampen, A. A1 - Thünemann, Andreas T1 - What does your gut see? – Silver nanoparticles in an artificial digestion N2 - Over the last decade nanoparticles are progressively included in products of our daily life. Due to their antimicrobial properties, silver nanoparticles are used in a high variety of consumer products ranging from food containers over medicine and textiles. Therefore, research on the toxicological potential of nanosilver becomes increasingly important. This includes investigations concerning uptake, distribution and excretion of the particles. However, little attention was paid to changes of physical and chemical properties of the particles in the human body. One of the most important questions is if the particles can pass the digestion process without altering their shape and size. In this study we report on a versatile system of ultra-small silver nanoparticles with a mean volume weighted radius of 3.1 nm and a narrow size distribution width of 20%. The nanoparticles’ coating of poly (acrylic acid) can easily be exchanged by biocompatible ligands like albumin or glutathione. The particles are thoroughly characterized by small angle X-ray scattering (SAXS), DLS, IR and UV/Vis spectroscopy. We used the particles in an artificial digestion procedure which mimics the gastro-intestinal passage (Figure 1). Thereby the changes in the size distribution during the digestion process were analytically monitored by SAXS. Additionally, we used as food components oil, starch, skimmed milk powder and mixture thereof to provide a preferably realistic environment. Large aggregates of up to 56 nm were formed in the absence of food additives. In contrast, the presence of oil and starch limit the radii of aggregates to about 10 nm. Milk powder shows strong protective properties resulting in only small aggregates of 6 nm radii. Our results indicate that silver can indeed pass the digestion process in a nanoscale form depending on the nanoparticle coating and additional ingredients. These results have an impact on future toxicological considerations regarding silver nanoparticle-containing consumer products. T2 - 5th Nano Today Conference CY - Waikoloa Village, HI, USA DA - 06.12.2017 KW - SAXS KW - Artificial digestion KW - Silver nanoparticles KW - Food additives PY - 2017 AN - OPUS4-43499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem A1 - Kastanias, Elaine A1 - Wurzler, Nina A1 - Hampel, Marco T1 - Spektroelektrochemische Analyse der Korrosionsprozesse von eisenreduzierenden Mikroorganismen N2 - Der Vortrag ist eine Zusammenfassung der Forschungsaktivitäten im FB 6.2 im Rahmen des Themenfeldprojekts MIC (TF-Material). T2 - DECHEMA/GfKORR-Fachgruppe "Mikrobielle Materialzerstörung und Materialschutz" CY - Berlin, Germany DA - 04.10.2017 KW - Korrosion KW - Mikrobiell induzierte Korrosion (MIC) KW - Lokale Elektrochemie KW - Spektroelektrochemie KW - Oberflächenverstärkte Raman Spektroskopie (SERS) KW - XANES PY - 2017 AN - OPUS4-43462 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - SAXS for the determination of the size distribution of nanoparticles: Application in catalysis N2 - The open source software packages SASfit1 and McSAS2 are widely used to determine the size distribution of nanoparticles. SASfit is based on classical curve fitting. The type of size distribution needs to be provided as constraint for analysis. Very often the lognormal size distribution is useful as shown for the characterization of single- and multimodal magnetic iron oxide particles. The use of SASfit is part of efforts to standardize analyzing methods for magnetic nanoparticles within the EU project NanoMag (www.nanomag-project.eu). In contrast to SASfit, it is not necessary to provide the type of size distribution when using the program McSAS. Both programs provide tools that allow the user to estimate uncertainties of the derived size distributions. Such is helpful in the development of nanoscale reference materials for environmental, health and safety measurements. As an example, a detailed study on using SAXS in the characterization of ultra-small-silver nanoparticles is presented. These particles are useful in the catalytic reduction of 4-nitrophenol and display an adjustable activity (see Figure). Figure. Core-shell silver nanoparticles catalyze the reduction of 4-nitrophenol and display an increasing catalytic activity when stabilized with different ligands in the line bovine serum albumin (BSA), glutathione (GSH) and polyacrylic acid (PAA).5 T2 - International SAXS Symposium CY - Graz, Austria DA - 26.09.2017 KW - SAXS KW - Small-angle X-ray scattering KW - Silver nanoparticles PY - 2017 AN - OPUS4-42251 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Unger, Wolfgang A1 - Schwibbert, Karin A1 - Thissen, A. A1 - Dietrich, P. T1 - Surface characterisation of biological samples with near-ambient pressure XPS N2 - The principle of NAP-XPS is explained, together with its relevance for biological samples. Further, ongoing work on NAP-XPS measurements on E. coli biofilms is presented. T2 - Seminar AG Weinhart, FU Berlin CY - Freie Universität, Berlin, Germany DA - 05.12.2016 KW - NAP-XPS KW - Biofilms KW - Alginate KW - E. coli PY - 2017 AN - OPUS4-43331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Silbernagl, Dorothee A1 - Ghasem Zadeh Khorasani, Media T1 - Improving polymer matrix additives for composite structures: a focus on boehmite N2 - The aims of the Research Unit „Acting Principles of Nano-Scaled Matrix Additives for Composite Structures“ (DFG FOR 2021) are based on different synergetic pathways. Challenges are to achieve an improved damage tolerance combined with unchanged processability and a proof of the nano-based effect from molecular scale up to structural level. First of all, a comprehensive understanding of the acting mechanisms of nano-scaled ceramic additives onto polymer matrices of continuous fibre reinforced polymer composites with respect to improved matrix dominated properties is in focus. To proof of the nanoscopic and microscopic effects up to structural level; experimental investigations start on the functional correlation between the particle properties and the resulting properties of the epoxy as suspension and in the solid state. This includes tests for the resulting composite structures as well. Along the entire process chain different multi-scale simulations are performed from molecular modelling up to the macroscopic, structural level. The combination of experimental investigations and simulation methods enables a holistic understanding of the acting principles and basic mechanisms. Specialized techniques based on Scanning Force Microscopy are the basis of our analysis of physicochemical properties of the boehmite nanoparticles and their polymer environment. A surface map of mechanical properties as an input for simulations facilitate a deeper understanding of such composites across all scales. This enables us to understand the macroscopic structure-property relationship and to predict failure mechanisms as well as routes for optimization. T2 - 92nd DKG annual meeting and symposium on high performance ceramics CY - Berlin, Germany DA - 19.03.2017 KW - Boehmite nanoparticle KW - Intermodulation AFM KW - Composite structures KW - Pull-out test KW - Thermoset KW - Crack propagation energy PY - 2017 AN - OPUS4-39519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Dietrich, P. A1 - Thissen, A. A1 - Schwibbert, Karin A1 - Unger, Wolfgang T1 - Characterisation of biofilms with near-ambient pressure XPS N2 - A drawback for X-ray photoelectron spectroscopy is that the measurements must be performed under ultra-high vacuum, which limits the type of samples which can be studied. However, by applying a differentially pumped aperture positioned close to the surface, even wet samples can be measured at near ambient pressure while the energy analyser is still under ultra-high vacuum, as illustrated below. Successful XPS-measurements with pressure up to 30 mbar have been reported using this approach, which opens up a new world of possibilities for ambient pressure measurements with XPS. While there are examples where NAP-XPS has been used to study electrochemical processes and heterogeneous catalysis, little attention has been paid to its potential use in biological materials. Until now, bacteria have only been characterised with conventional XPS, which requires tedious sample preparation usually involving freeze drying, a treatment that may degrade biological sample constituents. By studying biological samples in their native wet states, new insight about composition, absorption and transport of drugs through cell membranes and extracellular polymeric substance (EPS) layers can be obtained. Both artificial model-films of exopolysaccharides and biofilms of Escherichia Coli have been characterised at pressures ranging from ultra-high vacuum to 15 mbar by using SPECS’ EnviroESCA NAP-XPS instrument and conventional XPS. By applying antimicrobials to model biofilms, some of which are known to be resistant towards the antimicrobial in question, the distribution of antimicrobials in biofilms has been studied. Measurement capabilities and limitations of the approach will be discussed. T2 - European conferene on applications of surface and interface analysis (ECASIA 17) CY - Montpellier, France DA - 25.09.2017 KW - NAP-XPS KW - E. coli KW - Biofilms KW - Alginate PY - 2017 AN - OPUS4-42561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Mielke, Johannes A1 - Dohányosová, P. A1 - Müller, P. A1 - López-Vidal, S. T1 - Deposition of nanoparticles by electrospray for improved analysis by SEM/TEM and EDX N2 - Of many experimental techniques for measuring particle sizes and size distributions, electron microscopy (EM) is still considered as the gold standard, especially in the nano range (1–100 nm). Furthermore, high-resolution X-ray spectroscopy (EDX) in conjunction with EM can be applied to individul NPs. Preparation of an EM sample for generic particulate materials is a difficult task. Usually, the particles in a suspension are deposited on a support. However, this procedure includes the drying of larger solvent amounts on the substrate itself, and this can affect the spatial distribution of the deposited particles. One possibility to overcome this is the use of an electrospray system, where the suspension of particles is sprayed onto the substrate in charged droplets that are so small that they either dry off on the substrate immediately without affecting the position of particles, or even already during their flight time to the substrate. Additionally, the charging of particles minimizes agglomeration and aggregation, maximizing the collection of the EM grids. The prototype of an electrospray deposition System was tested. Electrospray is theoretically described since a long time, but no dedicated commercial instruments are available for the preparation of TEM grids yet, apart from electrostatic deposition of aerosols. Several materials have been sprayed onto TEM grids and the resulting particle distributions were evaluated. Operation parameters such as the sample flow-rate, capillary – substrate distance, electric field strength and sampling period length have been optimized. It was found that the particles deposited by electrospray generally show a much more homogeneous spatial distribution on the substrate and a substantial increase of the number of single particles (suited to automatic analysis). T2 - 17th European Conference on Applications of Surface and Interface Analysis (ECASIA 2017) CY - Montpellier, France DA - 24.09.2017 KW - Electrospray deposition KW - Nanoparticles KW - SEM KW - TEM KW - TEM grid PY - 2017 AN - OPUS4-42393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Taabache, Soraya A1 - Maskos, M. T1 - Controlled Self-Assembly of Janus Dendrimers via Microfluidics N2 - Unilamellar vesicles self-assembled in water from natural and synthetic phospholipids (liposomes), amphiphilic block copolymers (polymersomes), and more recently amphiphilic Janus dendrimers (dendrimersomes) as hollow soft structures in the nano size regime have attracted increasing interest as they can mimic primitive and contemporary biological membranes, and can be configured into biomimetic nanocapsules with application in nanomedicine such as gene, proteins and drug carriers or theranostics. Compared to other amphiphilic structures, the molecular structure of Janus dendrimers can be precisely controlled: by using the vast range of tools from organic chemistry their size, architecture, density, generation as well as the number of endgroups of the individual dendrons can be modified as desired. Unfortunately, the controlled production of the supramolecular aggregates made thereof is still a challenging task. Conventional batch-based techniques such as the solvent injection method or the film hydration method typically go along with a lack of control over mixing and thus over size, morphology and size distribution. The micromixer technology is a promising method for the controlled preparation of supramolecular assemblies as it allows control of mixing at microscale level. In addition, such microfluidic systems benefit from a high mixing efficiency, a low mixing time as well as from a reproducible and continuous synthesis. Herein, we report on the microfluidic-controlled self-assembly of Janus dendrimers as dendrimersomes and the impact of the mixing parameters on the self-assembly process. T2 - 10th International Dendrimer Symposium CY - Weihai, China DA - 05.08.2017 KW - Micromixers KW - Janus dendrimers KW - Vesicles KW - Self-assembly PY - 2017 AN - OPUS4-41464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frenzel, Florian T1 - Spectroscopic study of plasmon enhanced UPCON luminescence of silica-metal core-shell nanocomposites - status report N2 - The presentation focuses on the current state of the optical spectroscopic studies on plasmon enhanced upconversion luminescent processes of silica-metal core-shell nanocomposites. A general introduction of the upconversion process, the theoretical basis of plasmonic enhancement, the theoretical requirements in regard to NP architecture for plasmon enhanced UC will be outlined. The first proof-of-concept measurements show the difficulty in realization the theoretical measurement parameters in laboratory conditions and underline the need for shifting the experiments to single particle level.“ T2 - Gruppenseminar der Nanooptik an der HU Berlin, Prof. Benson, Institut für Physik, Raum 1‘404 CY - Berlin, Germany DA - 09.05.2017 KW - Upconversion KW - Pplasmon enhancement KW - Core-shell nanoparticles KW - Silca-metal nanoparticles PY - 2017 AN - OPUS4-50698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kästner, Claudia T1 - Food-dependent aggregation of silver nanoparticles during an artificial digestion N2 - In the last decade the utilization of silver nanoparticles in consumer related products is strongly enhanced. Therefore, many studies focus on investigations regarding their toxicological potential. This includes investigations concerning uptake, distribution and excretion of the particles. However, little attention was paid to changes of physical and chemical properties of the particles in the human body. A major question is if the particles are size and shape persistent and can survive the digestion process. In this study we analytically monitored the changes in the size distribution of colloidal silver during an artificial digestion process with the help of small angle X-ray scattering. We synthesized poly(acrylic acid) stabilized ultra-small silver nanoparticles with a radius of 3.1 nm and a size distribution width of 20%. The artificial digestion process mimics the gastro-intestinal passage and simulates the oral, gastric and small intestinal conditions. Additionally, we used as food components oil, starch, skimmed milk powder and mixture thereof to provide a preferably realistic environment. Large aggregates of up to 56 nm were determined in the absence of food additives. In contrast, the presence of oil and starch limit the radii of aggregates to about 10 nm. Only small aggregates of 6 nm radii were found in the presence of milk powder. It prevents primary particles from etching in the intestinal juice. Our results indicate that the silver nanoparticles can pass the digestion process in a nanoscale form but undergo a strong and food-dependent transformation in their state of aggregation. T2 - Australian Colloid and Interface Symposium 2017 CY - Coffs Harbour, New South Wales, Australia DA - 29.01.2017 KW - SAXS KW - Food additives KW - Aggregation PY - 2017 AN - OPUS4-39204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kästner, Claudia T1 - Creating the Silver Standard: Development of a Silver Nanoparticle Reference Material using SAXS N2 - The utilization of silver nanoparticles in consumer related products has significantly increased over the last decade, especially due to their antimicrobial properties. Today they are used in a high variety of products, which ranges from food containers over children toys and textiles. Therefore, research on the toxicological potential of silver in a nanoscale form becomes increasingly important for a high amount of studies. Unfortunately the results of these studies are extremely diverse and do not lead to a consistent evaluation of the toxicity of silver nanoparticles. The central problem lies in the use of a wide range of silver nanoparticles, which show a broad size distribution. To overcome this problem we report on the synthesis of ultra-small silver nanoparticles and their quantitative characterization by small-angle X-ray scattering. The particles are highly stable and show no aggregation for more than six months. SAXS analysis via a Monte Carlo data evaluation procedure reveal a narrow size distribution of the silver cores with a mean volume weighted radius of 3.0 nm and a distribution width of 0.6 nm. Dynamic light scattering provides a hydrodynamic radius of 10.0 nm and a PDI of 0.09. The particles are stabilized with poly(acrylic acid) (PAA) forming a shell with a thickness of 7.0 nm. It is foreseen to use these thoroughly characterized particles as reference material to compare the catalytic and biological properties of functionalized silver nanoparticles. As a first step the particles are used in the first world-wide inter-laboratory comparison of SAXS. This study reveals that SAXS shows highly reproducible results for particles in the sub-20 nm region independently on the type of instrument used. Furthermore, the stabilizing ligand PAA can be easily exchanged by biomolecules to modify the surface functionality. Replacements of PAA with glutathione (GSH) and bovine serum albumin (BSA) have been performed as examples. With this flexible system first applications regarding biological application in an artificial digestion procedure have been performed. Thereby the changes in size distribution and aggregation state were monitored by SAXS. T2 - SAXS Excites - International SAXS Symposium CY - Graz, Austria DA - 26.09.2017 KW - Silver nanoparticles KW - Artificial digestion KW - Aggregation KW - Reference material PY - 2017 AN - OPUS4-42289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Wollschläger, Nicole A1 - Pallase, L. A1 - Häusler, Ines A1 - Ortel, Erik A1 - Dirscherl, K. T1 - Characterization of Porous, TiO2 Nanoparticle Films Using On-Axis TKD in SEM – a New Nano-Analysis Tool for a Large-Scale Application N2 - A combined methodical approach is tested with respect to the characterization of the inner structure of porous TiO2 layers as typically used in modern dye sensitized solar cells (DSSC). Their performance is directly linked to the surface area of the pore network. The micrometer thick layer employed was manufactured by screen-printing of a starting TiO2 powder constituted of shape-controlled, bipyramidal anatase nanoparticles on FTO/glass substrates. The analytical methods exploited in our study are Focused Ion Beam (FIB) slicing followed by 3D reconstruction as well as the new approach transmission Kikuchi diffraction (TKD) technology in the scanning electron microscope (SEM). Size and shape distribution of the TiO2 NPs within the layer can be extracted. SEM in transmission mode and atomic force microscopy (AFM) have been used to verify the dimensional data obtained by the new combined methodical approach. Its analytical benefits but also the challenges and limitations are highlighted. T2 - Microscopy & Microanalysis 2017 Meeting CY - St. Louis, MO, USA DA - 06.08.2017 KW - Porous layers KW - TiO2 KW - Nanoparticles KW - Size and shape distribution KW - TKD KW - SEM PY - 2017 AN - OPUS4-41660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griepentrog, Michael T1 - Instrumented Indentation Testing (IIT) - A critical journey from the very first steps to the modern state of the art N2 - Nowadays the Instrumented Indentation Testing (IIT), in the nano range often named as nano indention, is one of the most commonly used methods to determine the mechanical properties of materials in the micro and nano range. This method is already extensive standardized in DIN EN ISO 14577 part 1-4. In the past, the application of this standard in testing praxis shows that the established values have an excellent precision. On the other side, the trueness as comparability of obtained results with reference values is not so good. To improve accuracy of IIT the use of a variable ε and the consideration of the lateral displacement during indentation became normative requirements during the last revision of ISO 14577. Starting with the beginning of instrumented indentation testing in 1898 the historical background and the main assumption of the Oliver and Pharr method will be explained and critical discussed. It will be shown how to apply the use of a variable ε and the consideration of the lateral displacement during indentation in the daily testing work to improve accuracy of IIT. Finally, ongoing standardization projects in the field of IIT will be briefly presented. T2 - Advanced nano-mechanical techniques for academic and industrial research. MML Conference and Workshop CY - Warwick, UK DA - 13.12.2017 KW - ISO 14577 KW - Instrumented Indentation Testing KW - Nanoindentation KW - IIT KW - Mechanical properties KW - Variable epsilon KW - Lateral displacement PY - 2017 AN - OPUS4-43466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Rudolf T1 - Antibodies on Beads - Nanokonjugate für die Analytik N2 - The presentation deals with the progess, the use of beads brings with it when developing and using immunoanalytical methods. While with conventional assays (e.g. ELISA) fill/empty/wash steps have to be performed within the same microplate well, antibodies on beads bring the possibility of incubating the sample with the capture antibodies in one compartment and then transport it, e.g. in microfluidic channels, to the site of detection. Especially magnetic nanoparticles, that can be captured and released easily, have a wide field of application. T2 - Wissenschaft trifft Wirtschaft - Analytik im Nanobereich CY - Berlin, Germany DA - 07.12.2017 KW - Nanoteilchen KW - Nanogold KW - Sensor KW - Mikrofluidik PY - 2017 AN - OPUS4-43359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sameith, Janin A1 - Schwibbert, Karin A1 - Tschiche, Harald A1 - Epperlein, Nadja A1 - Menzel, Friederike A1 - Hoffmann, Katrin A1 - Krüger, Jörg A1 - Resch-Genger, Ute A1 - Kunte, Hans-Jörg T1 - Microbially induced corrosion development of new analytical tools to study biofilm formation and corrosion processes N2 - Microbially induced corrosion (MIC) is a severe cost and risk factor for the oil and gas industry, water heat- and cooling systems, waste water management, and infrastructural constructions. The industrial preventions management of MIC focuses on eliminating present microorganisms, which leads to the repeated and time-consuming application of biocides. However, biocides are often only minor effective for microorganisms that live protected from these agents in a biofilm matrix formed on material surfaces. In recent years, microbiologist have renewed our vision on the electrochemical processes underlying material corrosion induced by sulfate reducing bacteria, but the knowledge at the level of multispecies biofilm formation and the effects of material’s properties are still rather scarce. Therefore, an interdisciplinary team of material scientists, chemists and microbiologists, established a MIC-research platform at the Federal Institute for Materials Research and Testing (BAM) to study the effects of material’s properties and biofilm formation on MIC. Using femtosecond laser pulse technology steel surfaces with defined nanostructures were manufactured. The test pieces were incubated using a flow-through chambers setup with different organisms relevant for biofilm studies. Our studies showed, that nanoscale structures severely affect the biofilm thickness and, hence, growth for health threatening organisms like E. coli and S. aureus, but also for MIC-relevant bacteria such as Fe(III)-reducing Shewanella spec. Another aspect of the biofilm matrix is the establishment of microscale environments with conditions, such as anaerobic or acidic microenvironments, which promotes a diverse multispecies community. However, the detection and visualization of such small-scale microenvironments is rather challenging. Further, it could directly indicate the activity of microorganism influencing or inducing corrosion processes. Therefore, dye-stained nanoscale particles, bearing pH-responsive fluorophores at the surface, were developed to measure the pH at the biofilm’s surface and within the matrix using confocal laser scanning microcopy. The particles will be further advanced to measure other environmentally relevant parameters, including oxygen concentration, and concentrations of selected metal ions indicative of corrosion of e.g., materials used for water pipelines. In the future, our platform and its analytical tools will be employed to study the formation of biofilms in dependency of the respective support material, its surface properties like roughness, and the microbial community. T2 - VAAM Jahrestagung CY - Würzburg, Germany DA - 05.03.2017 KW - MIC KW - Biophotonik KW - LIPSS KW - Nanoparticel based pH-probes PY - 2017 AN - OPUS4-39417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Wawrzynczyk, D. A1 - Kurnatowska, M. A1 - Arabasz, S. A1 - Prorok, K. A1 - Samoc, M. A1 - Strek, W. A1 - Bednarkiewicz, A. A1 - Pilch, A. A1 - Würth, Christian A1 - Kaiser, Martin T1 - Quantitation of luminescent properties of Yb and Ho co-doped NaYF4 colloidal nanoparticles - novel active-core-active-shell materials and novel characterization methods N2 - At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs) is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, we present here a series of core@shell NaYF4 UCNPs doped with Yb3+ and Ho3+ ions, where the same dopant concentrations were distributed in different particle architectures following the scheme: YbHo core and YbHo@..., …@YbHo, Yb@Ho, Ho@Yb, YbHo@Yb, and Yb@YbHo core-shell NPs. As revealed by quantitative steady state and time-resolved luminescence studies, the relative spatial distribution of the A and S ions in the UCNPs and their protection from surface quenching has critical impact on their luminescent characteristics. Interestingly, although the increased amount of Yb3+ ions boosts UCNP performance by increasing the absorption, the Yb3+ ions can also dissipate the energy stored in the material through energy migration to surface, thereby reducing the overall energy transfer efficiency to the activator ions. T2 - COST Workshop CY - Aveiro, Portugal DA - 30.06.2017 KW - Upconversion KW - Nanoparticle KW - Flourescence KW - Core-shell architecture KW - NIR KW - Absolute flourometry KW - Integrating sphere spectroscopy KW - Ho(III) KW - Yb(III) PY - 2017 AN - OPUS4-41161 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Hösl, S. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Herrmann, Antje A1 - Panne, Ulrich T1 - Metal detection at cellular levels by use of laser ablation ICP-MS N2 - We are using laser ablation (LA)-ICP-MS to image the local distribution of elements (metals and hetero-elements) directly or (metallo-)proteins by metal-tagged antibodies in cells and tissue indirectly. Different applications will be discussed to demonstrate the state of the art and to visualize the elemental distribution pattern in soft bio-materials (tissue, single cells). In the first application Pt-containing drugs for cancer treatment are investigated and elemental distribution pattern are shown for tissue samples from animal experiments. Different standardization and quantification schemes including isotope dilution analysis will be discussed. In the second application, which is dedicated to toxicological research, the up-take of nano-particles by single cells are discussed and metal containing stains are used to visualize the distribution of nano-particles, proteins and DNA in a single cell simultaneously. This information is correlated with the distribution of the nanoparticles to identify the cell compartments where nano-particles are enriched. Quantification schemes have been developed to transform the measured intensities into number of particles up taken by the cells. In the third and last application LA-ICP-MS is applied to visualize the local distribution of proteins, which are used as bio-markers for prostate cancer. For this purpose, biopsy samples from patients have been simultaneously stained by eight differently metal-tagged antibodies in a multiplex approach. Detection of house-keeping proteins serves as internal standards to overcome differences in protein expression. Additionally ink-jet printing of metal doped inks onto the surface of these tissue samples has been applied for internal standardization and drift corrections. Finally future trends to develop an “elemental microscope” will be discussed. T2 - PITTCON 2017 CY - Chicago, IL, USA DA - 05.03.2017 KW - Element-microscopy KW - LA-ICP-MS KW - Nanoparticles KW - Immuno-assays PY - 2017 AN - OPUS4-39364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - Nanoscience, SAXS and you N2 - A presentation demonstrating small-angle x-ray scattering and its applications. T2 - Invited talk CY - Deutsches GeoForschungsZentrum, Potsdam, Germany DA - 19.01.2017 KW - SAXS KW - Nanoscience PY - 2017 AN - OPUS4-39136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Wanka, Antje A1 - Kneipp, J. T1 - Method development for metal detection at cellular levels N2 - An overview about different analytical approaches will be presented of how to detect metals in individual biological cells by use of ICP-MS. For this purpose, we are using different sample introduction systems for ICP-MS for detection, imaging and quantification of metals at cellular levels. By use of laser ablation, we have studied the up-take by and distribution of metallic nanoparticles (Ag, Au) in single adherent cells (fibroblast cell line). Recently, we have developed staining techniques to image the protein (by a lanthanide containing chelate) and DNA (by an Ir-containing intercalator) distribution in single cells which can be combined with the nanoparticle studies. Additionally, we have developed an immunoassay by use of metal-tagged antibodies to identify the cell status of individual cells. Using pneumatic nebulization or microdroplet generation, we have also studied the up-take of nanoparticles and toxic metals as well as essential elements in single suspension cells using different ICP-MS mass spectrometric concepts (sector field instrument, triple-quad instrument, time of flight (CyTOF) instrument). For this purpose, the ICP-MS was operated in the single particle mode. First results of single cell ICP-MS (scICP-MS) will be presented for up-take of metallic (Ag) nanoparticles by THP 1 and macrophage cells and the strength of the different instruments will be discussed. T2 - 10th International Conference on Instrumental Methods of Analysis - IMA-2017 CY - Heraklion, Greece DA - 17.09.2017 KW - Imaging by LA-ICP-MS KW - Immunoassay KW - Metal-tagged antibodies PY - 2017 AN - OPUS4-42187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sameith, Janin T1 - BAM strategies for studies on microbial corrosion - Focus area: Materials - Microbially induced corrosion (MIC) N2 - Presentation of the MIC-project (Microbially Induced Corrosion) within the focus area Materials of the BAM. Strategies, developments and innovations in the area of analytical tools, surface modifications, polymer stability and biofilm-enhanced deteriorations of materials in the context of microbially induced corrosion processes. T2 - Gesellschaft für Korrosion e.V Arbeitskreismeeting: Mikrobielle Materialzerstörung CY - Frankfurt; DECHEMA, Germany DA - 09.02.2017 KW - MIC KW - Material KW - Biodetorioration PY - 2017 AN - OPUS4-39415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pisonero, J. A1 - Fandiño, J. A1 - Señorans, M. A1 - Halvor, J. A1 - Pfeifer, Jens A1 - Hofmann, T. A1 - Smid, P. A1 - Venzago, C. A1 - Richter, Silke A1 - Jakubowski, Norbert A1 - Sanz-Medel, A. A1 - Bordel, N. T1 - Fast elemental depth profile analysis of nano and micro layers with high sensitivity using pulsed glow discharge mass spectrometry N2 - Innovative material with outstanding physical and chemical properties are produced upon the deposition of thin and ultrathin coatings on different substrates. For instance, hard disks able to store Tera-bytes of information are based on the deposition of multiple nano-layers, which include magnetic and non-magnetic layers. Many other analogous examples, including photovoltaic cells, coated Al substrates, oxidized thin film composite membranes, coated glasses, coated polymers, etc. could be cited. The physical performance of these emerging materials is directly related to their chemical properties, including the elemental distribution within the different layers and at the layer-interfaces, or the presence of critical non-desired trace elements. Therefore, quality control and R+D advances require the development of direct solid analytical techniques able to provide fast multi-elemental chemical analysis of these materials, with high depth resolution (to monitor the different layers) and high sensitivity (to detect major, minor and trace elements). Atomic spectrometry techniques have long been used for direct elemental chemical characterization. Techniques, such as Secondary Ion Mass Spectrometry or Auger Electron Spectroscopy provide very valuable information about the chemical composition of the surfaces/coatings; however, they also have some major drawbacks, such as high operating costs, complex sample pre-treatment and handling, low sample throughput and/or severe matrix effects that result in difficult quantification procedures. To overcome some of these drawbacks Glow Discharge Mass Spectroscopy is proposed as a complementary methodology that provides an ideal solution for fast and accurate bulk and layer analyses. In this work, we evaluate the advantages and limitations of this technique and we discuss about recent progresses and new applications. T2 - JAI Conference , 15th Instrumental Analysis Conference CY - Barcelona, Spain DA - 03.10.2017 KW - GDMS KW - Pulsed KW - Depth profile PY - 2017 AN - OPUS4-46226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kastanias, Elaine A1 - Elert, Anna Maria A1 - Sturm, Heinz A1 - Özcan Sandikcioglu, Özlem T1 - Chemical and electrochemical interaction mechanisms of metal-reducing bacteria with gold surfaces N2 - The ubiquity of biofilms is accompanied by significant health and safety risks. Clarifying the interaction mechanisms of sessile bacteria with metal and metal oxide surfaces is of great interest to advance the development of new control strategies and novel anti-fouling surfaces which mitigate the detrimental effects of bio-fouling. The Shewanella genus is a faculatively aerobic, Gram-negative, exoelectrogenic bacterium known to demonstrate exceptional adaptability in respiratory capacities. Shewanella is often found in microbial communities within aquatic and sedimentary settings. During aerobic conditions, Shewanella utilizes oxygen as a terminal electron acceptor. During anaerobic conditions, respiration occurs via reduction of alternative terminal electron acceptors such as oxidized metals via extracellular electron transfer mechanisms involving electron shuttle molecules released by the bacteria. The purpose of this work is to investigate the mechanisms of bacterial attachment and subsequent biofilm formation on metallic surfaces. Using Shewanella sp. model biofilms, surface enhanced Raman spectroscopy (SERS) complemented with electrochemical techniques have been utilized to study this dynamic interaction. Additionally, to study the process of diffusion of extracellular electron shuttles, a model system comprised of calcium cross-linked alginate to mimic the architecture of bacterial extracellular polymeric substances has been used. Inert model substrates with consistent uniformity and high surface enhancement factor have been fabricated via the deposition of gold nano-islands on thin glass slides. Moreover, it has permitted modification of the surface chemistry and surface energy via surface functionalization using organothiol self-assembled monolayers. The presentation will summarize our results on the interplay between the initial settlement rate and biofilm formation kinetics of bacteria on metallic substrates with variable environmental conditions such as electrolyte composition, pH, in addition to surface characteristics such as hydrophobicity/hydrophilicity and external polarization. T2 - EUROCORR 2017 & 20thICC CY - Praha, Czech Republic DA - 04.09.2017 KW - Surface Enhanced Raman Spectroscopy (SERS) KW - Metal Reducing Bacteria (MRB) KW - Electron transfer PY - 2017 AN - OPUS4-43421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang A1 - Lippitz, A. A1 - Illgen, R. A1 - Ehlert, C. A1 - Girard-Lauriault, P.-L. A1 - Donskyi, Ievgen A1 - Haag, R. A1 - Adeli, M. T1 - Low pressure plasma, UV photo and wet chemical modification of graphite, graphene and carbon nano tubes N2 - Graphene is a two-dimensional carbon network with unique properties, including high mechanical stiffness, strength, and elasticity, outstanding electrical and thermal conductivity, and many others. Despite these advantages, its low solubility, poor reactivity and the limited accessibility of a well-defined basal plane are major challenges for applications. An ideal method to overcome these problems is the covalent attachment of functional molecules to its surface which enables further reactive modifications for specific applications. There is a number of different technologies for surface functionalization of graphene and related CNT materials. However, to get control on the functionalization process and to optimize the performance of the modified surfaces analytical tools for surface chemical characterization are required. X-ray absorption (NEXAFS) and photoelectron spectroscopy (XPS) have been identified to be rather powerful here. Specifically NEXAFS spectroscopy underpinned by quantum chemical spectrum simulations is unique in a way to address changes of aromaticity and defect formation at the graphene surface during functionalization. For relevant surface modification technologies, we present examples on how NEXAFS and XPS can perform well. All presented modifications aim on the production of platforms for defined functional 2D nanomaterials, as for example multifunctional hybrid architectures. In detail, we investigated: • Graphene and carbon nanotube functionalized by a Vacuum-Ultraviolet (VUV) induced photochemical process in NH3 or O2 atmospheres in order to introduce amino or hydroxy functionalities, respectively. • Br bonding on r.f. cw low pressure plasma brominated graphite surfaces by using Br2 and bromoform as plasma gases. • A wet chemical method for covalent functionalization of graphene sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. Here a reaction between 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized graphene sheets. T2 - The 17th European Conference on Applications of Surface and Interface Analysis CY - Montpellier, France DA - 24.09.2017 KW - Graphene KW - XPS KW - NEXAFS PY - 2017 AN - OPUS4-42787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg T1 - Complementary methodical approach for the analysis of a perovskite solar cell layered system N2 - Loss in efficiency of perovskite solar cells may be caused by structural and/or chemical alterations of the complex layered system. As these changes might take place either in the bulk and/or on the surface of the stratified material, analytical tools addressing both key issues are selected and combined. SEM/EDX combined with XPS were chosen as appropriate methodical approach to characterise perovskite laboratory cells in depth and complementary on top, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide (FTO), followed by three porous thin films of TiO2, ZrO2 and a thick monolithic carbon. The TiO2 film is subdivided into a dense layer covered by a porous one constituted of nanoparticles with a truncated bipyramidal shape. This layered system serves as the matrix for the perovskite. After infiltration of perovskite solution and annealing, EDX spectral maps on cross-sections of the specimen have been measured. The distribution of relevant elements – Si, Sn, Ti, Zr and C – correlates conclusively with layers visible in the acquired SEM images. Lead and iodine are distributed throughout the porous layers C, ZrO2 and TiO2. In a SEM micrograph taken of the cross-section of a sample after illumination, the glass substrate and all layers FTO, TiO2, ZrO2 as well as C are clearly identified. By EDX it was found that several weeks of ambient daylight did not change significantly the qualitative elemental composition of lead and iodine throughout the solar cell system. It was confirmed with EDX that nanoparticles identified in high-resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a time-dependent compositional and chemical altering was observed with XPS for the near-surface region of the outermost ~10 nm after two months of illumination. T2 - Microscopy & Microanalysis 2017 Meeting CY - St. Louis, MO, USA DA - 06.08.2017 KW - Thin films KW - EDX KW - XPS KW - SEM KW - Nanoparticles KW - Perovskite KW - TiO2 PY - 2017 AN - OPUS4-41664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griepentrog, Michael T1 - Dynamic instrumented indentation test application and standardisation N2 - The draft of part 5 of ISO 14577 specifies verification and calibration of testing machines for carrying out the measurement of the dynamic material response when an oscillatory force or displacement, with amplitudes small in comparison to the prescribed target values, is imparted to the indenter while the indenter is continuously loaded to a prescribed target load or target depth or while the load or displacement is held constant at a prescribed target value. In case of a material showing plastic-elastic behavior, the measured dynamic response is used for continuous evaluation of the dynamic stiffness of the contact as a function of depth and frequency. Using the dynamic stiffness of the contact a reduced dynamic modulus will be calculated. In case of a material showing visco-elastic behavior from the measured dynamic response also the dynamic contact damping coefficient as function of depth and frequency is evaluated continuously. Using dynamic contact stiffness and dynamic contact damping coefficient reduced lost and storage modulus for visco-elastic materials will be calculated. The main normative requirements of the draft are discussed and their applications are illustrated by examples from daily experimental praxis. T2 - 13th Conference on Local Mechanical Properties CY - Košice, Slovak Republic DA - 06.11.2017 KW - ISO 14577 KW - Instrumented indentation testing KW - Nanoindentation KW - IIT KW - Mechanical properties KW - Dynamic testing KW - Visco-elastic KW - Loss modul KW - Storage modul PY - 2017 AN - OPUS4-43468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Taabache, Soraya A1 - Maskos, M. T1 - Controlled self-assembly of Janus dendrimers via microfluidics N2 - Vesicles self-assembled in water from natural and synthetic phospholipids (liposomes), amphiphilic block copolymers (polymersomes), and more recently amphiphilic Janus dendrimers (dendrimersomes) as hollow soft structures in the nano size regime have attracted increasing interest as they can mimic primitive and contemporary biological membranes, and can be configured into biomimetic nanocapsules with application in nanomedicine such as gene, proteins and drug carriers or theranostics. Compared to other amphiphilic structures, the molecular structure of Janus dendrimers can be precisely controlled: by using the vast range of tools from organic chemistry their size, architecture, density, generation as well as the number of end groups of the individual dendrons can be modified as desired. Unfortunately, the controlled production of the supramolecular aggregates made thereof is still a challenging task. Conventional batch-based techniques such as the solvent injection method or the film hydration method typically go along with a lack of control over mixing and thus over size, morphology and size distribution. The micromixer technology is a promising method for the controlled preparation of supramolecular assemblies as it allows control of mixing at microscale level. In addition, such microfluidic systems benefit from a high mixing efficiency, a low mixing time as well as from a reproducible and continuous synthesis. Herein, we report on the microfluidic-controlled self-assembly of Janus dendrimers as dendrimersomes and the impact of the mixing parameters on the self-assembly process. T2 - 6th Annual workshop on biomaterials and their interactions with biological and model membranes 2017 CY - Altafulla, Spain DA - 07.09.2017 KW - Janus dendrimers KW - Dendrimersomes KW - Microfluidic PY - 2017 AN - OPUS4-41903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolter, Christian T1 - A bottom-up approach to study metal sulphides in brake friction materials at higher temperatures N2 - The impact of metal sulphides in brake friction materials on the friction behaviour of disc brakes was studied at two different temperatures and in two different atmospheres using a pin-on-disc device with powder supply. Powder mixtures were prepared by using a bottom-up approach, where magnetite is the main component, in which different metal sulphides are mixed in. At 400 °C, the resulting coefficients of friction are higher in air than in nitrogen atmosphere, which can be attributed to the generation of metal oxides and were confirmed by doing thermal analysis. T2 - The 6th World Tribology Congress - WTC 2017 CY - Beijing, China DA - 17.09.2017 KW - Brake friction materials KW - Artificial third body KW - Metal sulphies PY - 2017 AN - OPUS4-42451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Concrete casting robustness improvement due to active rheology control N2 - With ongoing innovation in process technology, the challenges of concrete technology are more and more focused on the rheological optimisation for these processes, since improper mixture stability or poor compaction ability negatively affect the concrete homogeneity and quality. However, along with the increasing complexity of today’s concrete mixture compositions, concrete becomes more prone to failure regarding the casting process. Variable properties of the raw materials typically cause changing workability. The reasons can be found among others in scattering water contents, physical or chemical properties of the cement or varying environmental temperatures. Robustness in the delicately adjusted rheology, however, is of utmost importance for modern and future process technology, from sprayed concrete over pumpable concrete towards 3D-printing, with regard to the long-term strength, the function and the durability. Typically, material induced changes cannot be identified easily due to the complex interactions of concrete constituents. Therefore, a precise and prompt counteraction is impossible. However, it is known that the yield stress can be controlled by addition of supplementary superplasticizer or stabilising agent. In combination with computerized process observation tools that can rapidly interpret and react on changes in the rheology, it is therefore thinkable, that only these two admixture types can adjust the rheology steadily and permanently, regardless of the actual root cause for observed macroscopic rheology change. The presentation will firstly give a comprehensive overview of effects at the interface between pore solution, particles and hydrates, which affect the rheology of fresh concrete. Secondly, ways are recommended how the rheology can be actively manipulated before eventually computerized methods are demonstrated that help to actively and rapidly assess and counteract performance scatter during steady casting processes. T2 - 2nd International Congress on Materials & Structural Stability CY - Rabat, Morocco DA - 21.11.2017 KW - Rheology KW - Control charts KW - Cusum KW - Additive manufacturing KW - Online quality control PY - 2017 AN - OPUS4-43542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. T1 - Morphological and surface analytical long-term investigations of a CH3NH3PbI3/TiO2 perovskite solar cell N2 - Long-term investigations over 20 weeks of a organic-inorganic hybrid solar cell with SEM/EDX and XPS will be presented. T2 - Kratos User Meeting 2017 CY - Stuttgart, Germany DA - 17.10.2017 KW - Perovskite solar cell KW - SEM with EDX KW - XPS PY - 2017 AN - OPUS4-42626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Taabache, Soraya A1 - Maskos, M. T1 - Controlled self-assembly of Janus dendrimers via microfluidics N2 - Vesicles self-assembled in water from natural and synthetic phospholipids (liposomes), amphiphilic block copolymers (polymersomes), and more recently amphiphilic Janus dendrimers (dendrimersomes) -5 as hollow soft structures in the nano size regime have attracted increasing interest as they can mimic primitive and contemporary biological membranes, and can be configured into biomimetic nanocapsules with application in nanomedicine such as gene, proteins and drug carriers or theranostics. Compared to other amphiphilic structures, the molecular structure of Janus dendrimers can be precisely controlled: by using the vast range of tools from organic chemistry their size, architecture, density, generation as well as the number of end groups of the individual dendrons can be modified as desired. Unfortunately, the controlled production of the supramolecular aggregates made thereof is still a challenging task. Conventional batch-based techniques such as the solvent injection method or the film hydration method typically go along with a lack of control over mixing and thus over size, morphology and size distribution. The micromixer technology is a promising method for the controlled preparation of supramolecular assemblies as it allows control of mixing at microscale level. In addition, such microfluidic systems benefit from a high mixing efficiency, a low mixing time as well as from a reproducible and continuous synthesis. Herein, we report on the microfluidic-controlled self-assembly of Janus dendrimers as dendrimersomes and the impact of the mixing parameters on the self-assembly process. T2 - 11th Young Scientists' Workshop, Fraunhofer ICT-IMM CY - Mainz, Germany DA - 27.09.2017 KW - Vesicles KW - Dendrimersomes KW - Micromixer PY - 2017 AN - OPUS4-42479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schäferling, Michael A1 - Näreoja, T. A1 - Deguchi, T. A1 - Fazeli, E. A1 - Peltomaa, R. A1 - Arppe, Riika A1 - Soukka, T. T1 - Sensing and Imaging of Intracellular pH Using Photon Upconversion Based Nanoprobes N2 - Sensing of intracellular pH is of particular interest in biomedical research since structure and function of biomolecules strongly depend on the concentration of protons in their environment. We have functionalized photon upconversion nano-particles (UCNPs) with pH responsive dyes to achieve nanoprobes for intracellular pH determination. The sensing mechanism is based on a resonance energy transfer (UC-RET) from the 550 nm emission of hexagonal nanocrystals of NaYF4: Yb3+,Er3+ to the pH-sensitive fluorophore pHrodoTM Red. The nanocrystals were coated with thin shells of aminosilane or highly branched polyethylenimine (PEI) with several nanometer layer thickness for coupling of the pH indicator. The nanoprobes are calibrated by ratiometric dual wavelength readout at 550 nm (reference signal) and 590 nm (sensor signal) and visualized using a scanning confocal fluorescence microscope with 980 nm excitation wavelength. It was found that PEI coating enables a higher coupling of indicator molecules on the particle surface, better signal to reference ratios in ratiometric readout and an improved cellular uptake compared to the aminosilane coated particles due to a more positive zeta potential. We studied the cellular uptake efficacy of the nanoprobes and determined to which type of compartment, lysosomes, endosomes or cytosol, the probes are targeted to by measuring the pH of their microenvironment. An in situ control was performed in live cells by a treatment with nigericin, whereby the pH of all intracellular compartments is set at extracellular level. Finally, we will show new strategies for the preparation of UCNP-dye conjugates with improved UC-RET efficiency to achieve higher acceptor (sensor) emission. T2 - 1st European / 10th German Biosensor Symposium CY - Potsdam, Germany DA - 20.03.2017 KW - Photon Upconversion KW - Nanoprobes KW - Chemical Sensing KW - PH KW - Live cell imaging PY - 2017 AN - OPUS4-40032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -