Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
- 2019 (33) (entfernen)
Dokumenttyp
- Vortrag (21)
- Posterpräsentation (7)
- Sonstiges (3)
- Zeitschriftenartikel (2)
Referierte Publikation
- nein (33) (entfernen)
Schlagworte
- Fluorescence (9)
- Dye (7)
- Nanoparticle (7)
- Quantum dot (7)
- Lifetime (6)
- Flow cytometry (5)
- Multiplexing (5)
- NIR (5)
- Assay (4)
- Bead (4)
- Calibration (4)
- Encoding (4)
- Method (4)
- Quantum yield (4)
- AIS (3)
- Barcoding (3)
- IgG (3)
- InP (3)
- Nanomaterialien (3)
- Nanoparticles (3)
- Protein G (3)
- SWIR (3)
- Uncertainty (3)
- Absolute fluorometry (2)
- Additive manufacturing (2)
- Antibody coating (2)
- Antikörper (2)
- Biosensor (2)
- Cleavable probe (2)
- Herceptin (2)
- IR (2)
- Immunoassay (2)
- Immunocapture (2)
- Immunoglobulins (2)
- Immunoprecipitation (2)
- Immunosensor (2)
- Integrating sphere spectroscopy (2)
- Nano (2)
- Nanomaterial (2)
- Oriented immobilization (2)
- Photoluminescence (2)
- Process monitoring (2)
- Protein A (2)
- Proximity-enhanced reaction (2)
- Quality assurance (2)
- Quantum dots (2)
- Surface chemistry (2)
- Thermography (2)
- 18HLT01 MetVes II (1)
- ABID (1)
- Acoustic Emission (1)
- Additive Fertigung (1)
- Additive Manufacturing (1)
- Advanced Materials (1)
- Affinity chromatography (1)
- Affinitätschromatographie (1)
- Affinitätsextraktion (1)
- Ameisensäure (1)
- Antibodies (1)
- Bead-based assay (1)
- Biochip (1)
- Bioconjugation (1)
- Borosilikatglas (1)
- Bundesoberbehörden (1)
- CE-ICP-MS (1)
- Carbon dot (1)
- Characterization (1)
- Click chemistry (1)
- Conductometry (1)
- Crosslinker (1)
- Diagnostic antibodies (1)
- Druckstabilität (1)
- Dye labeling (1)
- ELISA (1)
- EMPIR project (1)
- Extracellualr vesicles (1)
- Extracellular vesicles (EV) (1)
- FPLC (1)
- FTIR (1)
- Festphasenextraktion (1)
- Fingerprint (1)
- Fluorescence standard (1)
- Forschungsstrategie (1)
- Funtional Groups (1)
- Gallium doping (1)
- Glasmonolith (1)
- Glue (1)
- HPLC (1)
- Human antibodies (1)
- ICP-MS (1)
- Immobilisierung (1)
- Immobilization (1)
- Immunglobulin (1)
- Immunoaffinity extraction (1)
- Indium phosphide (1)
- Infrared Thermography (1)
- Integrating sphere spectroscopy, (1)
- Iron isotope fractionation (1)
- Korrelationsmatrix (1)
- LMD (1)
- LT-FCM (1)
- Lanthanide (1)
- Laser metal deposition (1)
- Ligand (1)
- Massenspektrometrie (1)
- Method comparison (1)
- Method validation (1)
- Methos comparision (1)
- Microarray (1)
- Microbially induced corrosion (1)
- Microparticle (1)
- Microparticles (1)
- NDT (1)
- Nanocrystal (1)
- Nanotechnologie (1)
- Neuartige Materialien (1)
- Next Generation Sequencing (1)
- Optical Emission Spectroscopy (1)
- Optical assay (1)
- Optical emission spectroscopy (1)
- Optical properties (1)
- Optical spectroscopy (1)
- PEG (1)
- PH (1)
- Paint (1)
- Peptide (1)
- Peptide Library (1)
- Peptide mass fingerprinting (1)
- Peptides (1)
- Performance validation (1)
- Phage Display (1)
- Polyethylene Glycol (1)
- Quality assurcance (1)
- Quantitative Analysis (1)
- Quantum yields (1)
- Reference material (1)
- Reference materials (1)
- Reference methods (1)
- Reference particles (1)
- Regeneration (1)
- Saure Hydrolyse (1)
- Screening (1)
- Semiconductor (1)
- Sensor (1)
- Single cell-ICP-ToF-MS (1)
- Single particle spectroscopy (1)
- Single particle-ICP-ToF-MS (1)
- Speciation analysis (1)
- Spectroscopy (1)
- Stabilization (1)
- Surface (1)
- Surface analysis (1)
- Surface group (1)
- Surface group analysis (1)
- Surfaces (1)
- Synthesis (1)
- Therapeutic antibodies (1)
- Time-resolved flow cytometry (1)
- Titan-Halterung (1)
- Trastuzumab (1)
- UpConversion (1)
- Upconversion (1)
- Vernetzung (1)
- biokompatibel (1)
- gesintert (1)
- single cell-ICP-ToF-MS (1)
- single particle-ICP-ToF-MS (1)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (33) (entfernen)
Eingeladener Vortrag
- nein (21)
What isotopes can do...
(2019)
Non-linear optical emitters are promising materials for energy applications and biotechnologies. Solid-state multi-band emitters like lanthanide doped up-conversion nanoparticles (UCNPs) show excellent photostability, are excitable in the near infrared (NIR), and show emission bands from the UV to SWIR spectral regions. The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion (ΦUC) and downshifting quantum efficiencies (ΦDS) of these materials, the excitation power dependent population, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We studied the fundamental changes of the luminescence properties of ß-NaYF4 UCNPs doped with Yb3+ and Er3+ depending on size, different surroundings such as aqueous and organic media, and different surface chemistries. We obtained further insights into shelling procedures, FRET optimization, influence of doping concentration, and advantages of different sensitizer ions.
Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior photophysical properties and enabled advancements in several key technologies of the 21st century and numerous technological applications. However, the most studied II-VI semiconductor nanocrystals contain the toxic heavy metal element cadmium, which is limiting their utilization in commercial applications. This has drawn the interest to alternative materials with less toxicity but having similar photophysical features.
The newest generation of TV screens based on QDs have shown that there is a promising environmentally friendly alternative with similar optoelectronic properties, namely indium phosphide (InP) QDs. InP QDs possess a bulk band gap of 1.35 eV with an exciton Bohr radius of ca. 10 nm and thus allow to tune their photoluminescence (PL) from the visible to the near-infrared. Tuning the size and shape of InP QDs and thus tailor their optoelectronic properties can be achieved by different strategies, which range from different types and concentrations of precursors, synthesis temperature or post-synthetic manipulations like etching. The incorporation of other elements like Gallium within the InP core synthesis is another possibility. Using a GaP intermediate layer before growing a ZnS shell has been shown to increase the PL quantum yield, which has been attributed to reduced lattice strain and the removal of phosphor vacancies. Different Ga precursors were investigated but a thorough investigation in terms of their reactivity, localization in the QD and influence on the photophysical properties is lacking to date.
In this contribution we will present the detailed investigation of the presence of two different Ga precursors within the InP core synthesis. Photophysical characterizations (steady-state and PL life-time measurements), transmission electron microscopy, XRD and EDX gave insights into the reactivity of the Ga precursors, the Ga localization in the InP core and influences on the photophysical properties. The variation of the precursor and surfactant concentration and the utilization of different ligands for the Ga precursor allowed tuning the PL emission towards the blue or the red. Depending on the used precursor type we observed the formation of larger-sized InP/GaP core/shell nanocrystals or the formation of InGaP alloy structures enabling to assess the blue range of emission (475 nm).
For metal-based additive manufacturing, sensors and measuring systems for monitoring of the energy source, the build volume, the melt pool and the component geometry are already commercially available. Further methods of optics, spectroscopy and non-destructive testing are described in the literature as suitable for in-situ application, but there are only a few reports on practical implementations.
Therefore, a new BAM project aims to develop process monitoring methods for the in-situ evaluation of the quality of additively manufactured metal components. In addition to passive and active thermography, this includes optical tomography, optical emission and absorption spectroscopy, eddy current testing, laminography, X-ray backscattering and photoacoustic methods. These methods are used in additive manufacturing systems for selective laser melting, laser metal deposition and wire arc additive manufacturing. To handle the sometimes huge amounts of data, algorithms for efficient preprocessing are developed and characteristics of the in-situ data are extracted and correlated to defects and inhomogeneities, which are determined using reference methods such as computer tomography and metallography. This process monitoring and fusion of data of different measurement techniques should result in a significant reduction of costly and time-consuming, destructive or non-destructive tests after the production of the component and at the same time reduce the production of scrap.
Here, first results of simultaneous measurements of optical emission spectroscopy and thermography during the laser metal deposition process using 316L as building material are presented. Temperature values are extracted from spectroscopic data by fitting of blackbody emission spectra to the experimental data and compared with results from a thermographic camera. Measurements with and without powder flow reveal significant differences between welding at a pristine metal surface and previously melted positions on the build plate, illustrating the significant influence of the partial oxidation of the surface during the first welding process on subsequent welding. The measurement equipment can either be mounted stationary or following the laser path. While first results were obtained in the stationary mode, future applications for online monitoring of the build of whole parts in the mobile mode are planned.
This research was funded by BAM within the focus area Material.
Organic and inorganic micro- and nanoparticles are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. Typically, these applications require further functionalization of the particles with, e.g., antifouling ligands, targeting bioligands, stimuli-responjsive caps, or sensor molecules. Besides serving as an anchor point for subsequent functionalization, the surface chemistry of these particles also fundamentally influences their interaction with the surrounding medium and can have a significant effect on colloidal stability, particle uptake, biodistribution, and particle toxicity in biological systems. Moreover, functional groups enable size control and tuning of the surface during the synthesis of particle systems.
For these reasons, a precise knowledge of the chemical nature, the total number of surface groups, and the number of groups on the particle surface that are accessible for further functionalization is highly important. In this contribution, we will will discuss the advantages and limitiations of different approaches to quantify the amount of commonly used surface functional groups such as amino,[1,2] carboxy,[1,2] and aldehyde groups.[3] Preferably, the quantification is carried out using sensitive and fast photometric or fluorometric assays, which can be read out with simple, inexpensive instrumentation and can be validated by complimentary analytic techniques such as ICP-OES and quantitative NMR.
Die gemeinsame Forschungsstrategie der Bundesoberbehörden zur Nanotechnologie wurde 2016 veröffentlicht. Die darin enthaltenen Aufgaben wurden von den Bundesoberbehörden vielfältig bearbeitet. Diese Präsentation gibt einen Überblick über die Projekte, die von der BAM bis 2019 bearbeitet wurden/werden und sich in den Rahmen der Forschungsstrategie einordnen.
Multiplexed encoding schemes of nano- and micrometer sized particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. The fluorescence parameter lifetime has been, however, barely exploited. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the excitation and emission wavelength, thus reducing instrument costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically < 10 ns, the fluorescence LTs of ternary semiconductor QDs that represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This present a time region that can be barely covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed and the encoded particles will be then used for fluorescence assays for the analysis of several targets in parallel. Therefor the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs In one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain.
Relative and Absolute Methods for Measuring Photoluminescence Quantum Yields of UV/vis/NIR Emitters
(2019)
One of the key spectroscopic performance parameters of molecular and particulate emitters is the photoluminescence quantum yield (PL QY) that provides a direct measure for the number of emitted per absorbed photons. This triggered the interest in methods suitable for measuring this property for emitters in various environments in the UV/vis/NIR and above 1000 nm as well as on the ensemble and single emitter level. Moreover, for nonlinear emitters like lanthanide-based upconversion nanocrystals methods including instrumentation for power density-dependent PL QY studies are required.
An overview of the research activities in Division Biophotonics of BAM is given and suitable relative and absolute methods for the deter-mination of PL QY of organic dyes and different types of application-relevant nanomaterials in dispersion and in the solid state are presen-ted. This covers also the design and calibration of integrating sphere setups, achievable uncertainties, and candidates for PL QY reference materials.
The project ProMoAM is presented. The goal of the project is to evaluate which NDT techniques or combination of techniques is suited for in-situ quality assurance in additive manufacturing of metals. To this end, also 3d-data fusion and visualization techniques are applied. Additional ex-situ NDT-techniques are used as references for defect detection and quantification. Feasability studies for NDT-techniques that are presently not applicable for in-situ use are performed as well.
The presentation gives a brief overview of the whole project and the different involved NDT-techniques.