TY - CONF A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Towards automated scanning electron microscopy image analysis of core-shell microparticles for quasi-3D determination of the surface roughness N2 - Core-shell (CS) particles have been increasingly used for a wide range of applications due to their unique properties by merging individual characteristics of the core and the shell materials. The functionality of the designed particles is strongly influenced by their surface roughness. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task for Scanning Electron Microscopy (SEM). The SEM images contain two-dimensional (2D) information providing contour roughness data only from the projection of the particle in the horizontal plane. This study presents a practical procedure to achieve more information by tilting the sample holder, hence allowing images of different areas of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, quasi three-dimensional (3D) information is obtained. Three types of home-made particles were investigated: i) bare polystyrene (PS) particles, ii) PS particles decorated with a first magnetic iron oxide (Fe3O4) nanoparticle shell forming CS microbeads, iii) PS/Fe3O4 particles closed with a second silica (SiO2) shell forming core-shell-shell (CSS) microbeads. A series images of a single particle were taken with stepwise tilted sample holder up to 10° by an SEM with high-resolution and surface sensitive SE-InLens® mode. A reliable analysis tool has been developed by a script in Python to analyze SEM images automatically and to evaluate profile roughness quantitatively, for individual core-shell microparticles. Image analysis consists of segmentation of the images, identifying contour and the centre of the particle, and extracting the root mean squared roughness value (RMS-RQ) of the contour profile from the particle projection within a few seconds. The variation in roughness from batch-to-batch was determined with the purpose to set the method as a routine quality check procedure. Flow cytometry measurements provided complementary data. Measurement uncertainties associated to various particle orientations were also estimated. T2 - ICASS 5th International Conference on Applied Surface Science CY - Palma, Mallorca, Spain DA - 25.04.2022 KW - Core-shell particles KW - Image analysis KW - Roughness KW - Scanning electron microscopy PY - 2022 AN - OPUS4-54774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Vom Indikatormolekül zum Sensorpartikel - unterwegs zu leistungsfähigen miniaturisierten Analyseplattformen T2 - IGAS Jahreskolloquium CY - Berlin, Germany DA - 2008-11-10 PY - 2008 AN - OPUS4-18545 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Novel Modular Sensors: Design of Efficient Probes for Various Analytes Utilizing the Phenoxazinone Chromophore T2 - Tag der Chemie CY - Potsdam, Germany DA - 2004-07-07 PY - 2004 AN - OPUS4-5353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Macrocycles in a Different Light: The Influence of the Nature and Substitution Pattern of Heteroatoms on the Photophysics of Chromophore-Appended Crown Ethers T2 - 28th International Symposium on Macrocyclic Chemistry CY - Gdansk, Poland DA - 2003-07-13 PY - 2003 AN - OPUS4-4889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Intramolecular Charge-Transfer Characteristics of Fluorescent Donor-[Ethynyl-Donor]n (n=1,2) Dyads and Triads T2 - 8th Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes CY - Prague, Czech Republic DA - 2003-08-24 PY - 2003 AN - OPUS4-4894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - A hybrid chemosensor material for the colorimetric and fluorometric detection of long-chain carboxylates T2 - 9th Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes CY - Lisbon, Portugal DA - 2005-09-04 PY - 2005 AN - OPUS4-7428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - A Chromo- and Fluorogenic Hybrid Chemosensor Material for the Detection of Long-chain Carboxylates T2 - ANAKON 2005 CY - Regensburg, Germany DA - 2005-03-15 PY - 2005 AN - OPUS4-7427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Functional red/NIR dyes and hybrid sensor materials T2 - Working Group Meeting, COST D-31, Working Group 001204 "New Materials for Anion Sensing", School of Chemistry CY - Birmingham, England DA - 2008-01-25 PY - 2008 AN - OPUS4-18547 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Biomimetically Inspired Sensing of Ionic and Neutral Species with Organically Modified Mesoporous Silica Materials T2 - First International Conference on Multifunctional, Hybrid and Nanomaterials CY - Tours, France DA - 2009-03-15 PY - 2009 AN - OPUS4-20644 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Biyikal, Mustafa A1 - Rurack, Knut T1 - Embedded sensor based on tandem smartphone-microfluidic device for the detection of TNT in surface and sea waters N2 - The globe's seas were used as dumping ground after the world wars and those millions of ammunition, most of all containing 2,4,6-trinitrotoluene (TNT), represent a pressing danger for fishermen, dredging operations, submarine cable installations and tourism. We developed an extremely selective indication method for TNT based on a specific reaction that produces a highly fluorescent compound. The indication system was integrated into a microfluidic PDMS chip for the solid-liquid extraction of TNT from water samples, offering environmental monitoring possibilities. Combining the advantages of a light-up indicator, microfluidics and a smartphone as detector, the embedded sensor allows for the remote and rapid detection of TNT down to ng in surface and sea waters. T2 - µTAS 2020 CY - Online meeting DA - 05.10.2020 KW - Smartphone KW - Rapid test KW - TNT KW - Ammunition KW - Schnelltest KW - Munition PY - 2020 AN - OPUS4-51444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Multifunctional hybrid microparticles for rapid cytometric and microfluidic mix-&-detect bioassays N2 - Besides the application-oriented parameters selectivity and sensitivity, simplicity and speed as well as robustness and reliability are the key features that determine success, dissemination and acceptance of analytical assays and methods for use in the field. For bioassays based on antibodies or nucleic acid binders, bead-based assays have become one of the main working horses of lab-based methods. However, these approaches are often limited by complicated and time-consuming workflows, which are mainly compensated by massive parallelisation, keeping the average cost and time-to-result within acceptable limits due to the sheer number and constant flow of samples processed. In on-site applications, where analyses need to be performed on suspicion or on demand because results are needed as quickly as possible for proactive decision making, the number, frequency and type of samples are much more diverse, so analytical assays need to be adapted to remain cost-effective and operable by non-expert users in environments where no lab infrastructure is available. With this in mind, we have developed a multifunctional hybrid microparticle platform that enables fast and simple mix-&-detect bioassays in combination with fluidic cytometry- and chip-based analytical methods. The present contribution will give an overview of the beads, their functions and how they can be combined with immunoanalytical and nucleic acid-based detection technologies. Starting from simple polymeric core/silica shell particles [1], we have progressively introduced coding [2,3], anti-fouling [2], high-surface area [4] and magnetic schemes [5] and in recent years have shown how these beads can be used in simple mix-&-detect assays for a range of different environmental, health and food analytes [1-5]. In addition to cytometry, we have also successfully implemented such assays using miniaturised microfluidic and strip-based approaches [6]. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Bead-based assay KW - Core-shell particles KW - Lab-on-a-chip KW - Mycotoxin PY - 2025 AN - OPUS4-62766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Development and Characterization of a Photostable Boron-dipyrromethene Dye as a Versatile Probe of the Analysis of Surface Functional Groups T2 - Smart Surfaces 2012 CY - Dublin, Ireland DA - 2012-03-06 PY - 2012 AN - OPUS4-27302 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Implementing Signal Amplification Features with Gated Mesoporous Sensory Hybrids for Methymercury Determination T2 - Hybrid Materials 2011 CY - Strasbourg, France DA - 2011-03-03 PY - 2011 AN - OPUS4-23935 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Test strip-based fluorescence detection of fluoride in aqueous media with a BODIPY-linked hydrogen bonding receptor T2 - International Conference on Photochemistry (ICP 2013) CY - Leuven, Belgium DA - 2013-07-21 PY - 2013 AN - OPUS4-28947 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Preparation of hybrid particle architectures for single microparticle-based detection in suspension arrays using FRET T2 - Tag der Chemie 2013 CY - Potsdam, Germany DA - 2013-06-27 PY - 2013 AN - OPUS4-28948 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Reference-free total reflection X-ray fluorescence analysis for surface functional group quantification of funtional groups on surfaces for bio-analytical applications T2 - E-MRS 2014 Spring Meeting CY - Lille, France DA - 2014-05-26 PY - 2014 AN - OPUS4-30787 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartelmeß, Jürgen A1 - Gawlitza, Kornelia A1 - Bartholmai, Matthias A1 - Rurack, Knut T1 - Developments towards the fluorescence based sensing of hazardous gases N2 - Fluorescence based sensing is a versatile approach for the trace analysis outside of the laboratory, requiring suitable sensor materials and their integration into sensing devices. The versatility of fluorophores as probes, especially in terms of the possibility to tailor their optical as well as their recognition properties by synthetic modifications in a wide range, renders them a superior active component for the preparation of optical sensor devices. Recent works at BAM in this field include, for example, the detection of nerve gas agents, illustrating impressively the aforementioned benefits of fluorophores in optical sensing applications. In the interdisciplinary approach presented here, we target hazardous gases such as ammonia, benzene, and hydrogen sulfide, next to others, which pose a major threat to human health and environmental safety and for which the availability of a sensitive and reliable detection method is highly desirable. The dyes presented follow a “turn-on” fluorescence schematic which allows for the selective and sensitive detection of the respective gaseous analyte. The immobilization of the probe in polymeric matrices is then the next step toward the fabrication of a prototype device for molecular sensing. T2 - Colloquium of Optical Spectrometry (COSP) 2017 CY - Berlin, Germany DA - 27.11.2017 KW - Gas sensing KW - Fluorescence KW - KonSens PY - 2017 AN - OPUS4-43209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Fluorescent mesoporous silicia materials discriminating Ag(l) and Hg (II) T2 - 25th Congress of the Analytical Chemistry Division of the Italian Chemical Society CY - Trieste, Italien DA - 2015-09-13 PY - 2015 AN - OPUS4-33635 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -