TY - JOUR A1 - Meyer, S. A1 - Timmel, S. A1 - Richter, S. A1 - Werner, M. A1 - Gläser, M. A1 - Swatek, S. A1 - Braun, Ulrike A1 - Hagendorf, C. T1 - Silver nanoparticles cause snail trails in photovoltaic modules JF - Solar energy materials & solar cells N2 - After some months of operation, a number of PV modules develop a discolouration defect called 'snail trails', or 'snail traces', which appear as irregular dark stripes across the cells. Whereas these traces were soon identified as discoloured silver contacts along the cell edges or at micro cracks, the chemical and mechanistic reasons for this phenomenon have not yet been resolved in detail. In this work we show that silver nanoparticles accumulating within the encapsulation foil cause the brownish discolouration, and that certain additives of encapsulation and back sheet foils trigger the formation of these nanoparticles. KW - Snail trails KW - Cell cracks KW - Encapsulation foil KW - Ag contact finger KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1016/j.solmat.2013.11.013 SN - 0927-0248 VL - 121 SP - 171 EP - 175 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-30059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Behnke, Thomas A1 - Grabolle, Markus A1 - Resch-Genger, Ute T1 - Nanoparticle-encapsulated vis- and NIR-emissive fluorophores with different fluorescence decay kinetics for lifetime multiplexing JF - Analytical and bioanalytical chemistry N2 - Bioanalytical, clinical, and security applications increasingly require simple, efficient, and versatile strategies to measure an ever increasing number of analytes or events in parallel in a broad variety of detection formats as well as in conjunction with chromatographic separation techniques or flow cytometry. An attractive alternative to common optical multiplexing and encoding methods utilizing spectral multiplexing/color encoding and intensity encoding is lifetime multiplexing, which relies on the discrimination between different fluorescent reporters based on their fluorescence decay kinetics. Here, we propose a platform of surface-functionalizable polymeric nanoparticles stained with fluorophores differing in their fluorescence lifetimes as a new multiplexing and encoding approach. Proof-of-concept measurements with different sets of lifetime-encoded polystyrene nanoparticles are presented, obtained via staining of preformed particles with visible (vis)- and near-infrared (NIR)-emissive organic dyes, which display very similar absorption and emission spectra to enable excitation and detection at the same wavelengths, yet sufficiently different fluorescence decay kinetics in suspension, thereby minimizing instrumentation costs. Data analysis was performed with a linear combination approach in the lifetime domain. Our results and first cell experiments with these reporter sets underline the suitability of our multiplexing strategy for the discrimination between and the quantification of different labels. This simple and versatile concept can be extended to all types of fluorophores, thereby expanding the accessible time scale, and can be used, e.g., for the design of labels and targeted probes for fluorescence assays and molecular imaging, cellular imaging studies, and barcoding applications, also in conjunction with spectral and intensity encoding. KW - Fluorescent label KW - Multiplexing KW - Optical KW - encoding KW - Lifetime multiplexing KW - Fluorescence lifetime imaging FLIM KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1007/s00216-013-7597-3 SN - 1618-2642 SN - 1618-2650 VL - 406 IS - 14 SP - 3315 EP - 3322 PB - Springer CY - Berlin AN - OPUS4-30077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rades, Steffi A1 - Salge, T. A1 - Schmidt, R. A1 - Hodoroaba, Vasile-Dan T1 - Need for large-area EDS detectors for imaging nanoparticles in a SEM operating in transmission mode JF - Microscopy and microanalysis KW - EDS KW - EDX KW - Nanoparticles KW - High-resolution KW - SEM KW - T-SEM KW - Large-area EDS PY - 2014 DO - https://doi.org/10.1017/S1431927614005030 SN - 1431-9276 SN - 1435-8115 VL - 20 IS - Suppl. S 3 SP - 662 EP - 663 PB - Cambridge University Press CY - New York, NY AN - OPUS4-31389 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Motzkus, C. A1 - Macé, T. A1 - Vaslin-Reimann, S. T1 - Performance of high-resolution SEM/EDX systems equipped with transmission mode (TSEM) for imaging and measurement of size and size distribution of spherical nanoparticles JF - Microscopy and microanalysis N2 - The analytical performance of high-resolution scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) for accurate determination of the size, size distribution, qualitative elemental analysis of nanoparticles (NPs) was systematically investigated. It is demonstrated how powerful high-resolution SEM is by using both mono- and bi-modal distributions of SiO2 airborne NPs collected on appropriate substrates after their generation from colloidal suspension. The transmission mode of the SEM (TSEM) is systematically employed for NPs prepared on thin film substrates such as transmission electron microscopy grids. Measurements in the transmission mode were performed by using a 'single-unit' TSEM transmission setup as manufactured and patented by Zeiss. This alternative to the 'conventional' STEM detector consists of a special sample holder that is used in conjunction with the in-place Everhart–Thornley detector. In addition, the EDX capabilities for imaging NPs, highlighting the promising potential with respect to exploitation of the sensitivity of the new large area silicon drift detector energy dispersive X-ray spectrometers were also investigated. The work was carried out in the frame of a large prenormative VAMAS (Versailles Project on Advanced Materials and Standards) project, dedicated to finding appropriate methods and procedures for traceable characterization of NP size and size distribution. KW - Transmission scanning electron microscopy/microscope (TSEM, T-SEM, STEM) KW - High-resolution scanning electron microscope (SEM) KW - Transmission KW - SiO2 KW - Nanoparticles KW - Size KW - Size distribution KW - EDX KW - Large area SDD PY - 2014 DO - https://doi.org/10.1017/S1431927614000014 SN - 1431-9276 SN - 1435-8115 VL - 20 IS - 2 SP - 602 EP - 612 PB - Cambridge University Press CY - New York, NY AN - OPUS4-30612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Unger, Wolfgang T1 - Inspection of morphology and elemental imaging of single nanoparticles by high-resolution SEM/EDX in transmission mode JF - Surface and interface analysis N2 - In the frame of the European project NanoValid, potential candidates of reference nanomaterials are manufactured and systematically characterized in particular with respect to their morphology (shape, size and size distribution). In this study, by exploiting the transmission operation mode in a high-resolution SEM, known as transmission SEM, the potential of this methodical approach is demonstrated by means of representative examples of nanoparticles. The method enables quick and accurate morphological inspection and systematic characterization. Energy dispersive X-ray spectroscopy imaging of single nanoparticles by using the transmission mode is demonstrated as feasible, too. KW - Single nanoparticles KW - SEM KW - TEM KW - T-SEM KW - EDX KW - Imaging KW - Transmission KW - NanoValid KW - Scanning electron microscopy (SEM) KW - High-resolution KW - Transmission in SEM KW - Energy dispersive KW - X-ray spectroscopy KW - Nanoparticles KW - Characterization PY - 2014 DO - https://doi.org/10.1002/sia.5426 SN - 0142-2421 SN - 1096-9918 VL - 46 IS - 10-11 SP - 945 EP - 948 PB - Wiley CY - Chichester AN - OPUS4-31577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rades, Steffi A1 - Wirth, Thomas A1 - Unger, Wolfgang T1 - Investigation of silica nanoparticles by Auger electron spectroscopy (AES) JF - Surface and interface analysis N2 - High-priority industrial nanomaterials like SiO2, TiO2, and Ag are being characterized on a systematic basis within the framework of the EU FP7 research project NanoValid. Silica nanoparticles from an industrial source have been analyzed by Auger electron spectroscopy. Point, line, and map spectra were collected. Material specific and methodological aspects causing the special course of Auger line scan signals will be discussed. KW - Nanoparticles KW - Auger electron spectroscopy KW - Surface analysis PY - 2014 DO - https://doi.org/10.1002/sia.5378 SN - 0142-2421 SN - 1096-9918 VL - 46 IS - 10-11 SP - 952 EP - 956 PB - Wiley CY - Chichester AN - OPUS4-31604 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giménez, C. A1 - Climent Terol, Estela A1 - Aznar, E. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Marcos, D. A1 - Amorós, P. A1 - Rurack, Knut T1 - Towards chemical communication between gated nanoparticles JF - Angewandte Chemie / International Edition N2 - The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects. We believe that the conceptual idea that nanodevices can be designed to communicate with one another may result in novel applications and will boost further advances towards cooperative systems with complex behavior as a result of the communication between simple abiotic individual components. KW - Chemical communication KW - Gated nanoparticles KW - Mesoporous materials KW - Nanoparticles community KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1002/anie.201405580 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 53 IS - 46 SP - 12629 EP - 12633 PB - Wiley-VCH CY - Weinheim AN - OPUS4-32136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kennedy, D.C. A1 - Orts-Gil, G. A1 - Lai, C.-H. A1 - Müller, Larissa A1 - Haase, A. A1 - Luch, A. A1 - Seeberger, P.H. T1 - Carbohydrate functionalization of silver nanoparticles modulates cytotoxicity and cellular uptake JF - Journal of nanobiotechnology N2 - Background Increasing use of silver nanoparticles (Ag-NPs) in various products is resulting in a greater likelihood of human exposure to these materials. Nevertheless, little is still known about the influence of carbohydrates on the toxicity and cellular uptake of nanoparticles. Methods Ag-NPs functionalized with three different monosaccharides and ethylene glycol were synthesized and characterised. Oxidative stress and toxicity was evaluated by protein carbonylation and MTT assay, respectively. Cellular uptake was evaluated by confocal microscopy and ICP-MS. Results Ag-NPs coated with galactose and mannose were considerably less toxic to neuronal-like cells and hepatocytes compared to particles functionalized by glucose, ethylene glycol or citrate. Toxicity correlated to oxidative stress but not to cellular uptake. Conclusions Carbohydrate coating on silver nanoparticles modulates both oxidative stress and cellular uptake, but mainly the first has an impact on toxicity. These findings provide new perspectives on modulating the bioactivity of Ag-NPs by using carbohydrates. KW - Silver KW - Nanoparticles KW - Carbohydrates KW - Nanotoxicology KW - Bio-Interfaces PY - 2014 UR - http://www.jnanobiotechnology.com/content/12/1/59 DO - https://doi.org/10.1186/s12951-014-0059-z SN - 1477-3155 VL - 12 IS - 59 SP - 1 EP - 8 PB - BioMed Central CY - London AN - OPUS4-34345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -