Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
- 2019 (68) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (37)
- Vortrag (21)
- Posterpräsentation (7)
- Sonstiges (3)
Schlagworte
- Fluorescence (16)
- Quantum yield (13)
- Lifetime (12)
- Dye (9)
- Nanoparticle (8)
- Photoluminescence (8)
- NIR (7)
- Nano (7)
- Nanomaterial (7)
- Quantum dot (7)
- Lanthanide (6)
- AIS (5)
- Flow cytometry (5)
- Method (5)
- Multiplexing (5)
- Photophysics (5)
- Quantum dots (5)
- Sensor (5)
- Assay (4)
- Bead (4)
- Calibration (4)
- Encoding (4)
- Mechanism (4)
- Nanoparticles (4)
- Surface chemistry (4)
- Barcoding (3)
- Energy transfer (3)
- IgG (3)
- InP (3)
- Indium phosphide (3)
- Nanomaterialien (3)
- Protein G (3)
- Quality assurance (3)
- SWIR (3)
- Uncertainty (3)
- Upconversion nanoparticle (3)
- Absolute fluorometry (2)
- Additive manufacturing (2)
- Advanced Materials (2)
- Antibody coating (2)
- Antikörper (2)
- Biosensor (2)
- Cleavable probe (2)
- Cytotoxicity (2)
- Degradation (2)
- Funtional Groups (2)
- Herceptin (2)
- IR (2)
- Immunoassay (2)
- Immunocapture (2)
- Immunoglobulins (2)
- Immunoprecipitation (2)
- Immunosensor (2)
- Integrating sphere spectroscopy (2)
- Oriented immobilization (2)
- PEG (2)
- Probe (2)
- Process monitoring (2)
- Protein A (2)
- Proximity-enhanced reaction (2)
- Quantitative Analysis (2)
- Semiconductor nanocrystal (2)
- Sensitization (2)
- Single particle spectroscopy (2)
- Spectroscopy (2)
- Synthesis (2)
- Ternary quantum dots (2)
- Thermography (2)
- Upconversion (2)
- Upconversion nanoparticles (2)
- fluorescence (2)
- 18HLT01 MetVes II (1)
- ABID (1)
- AIS QD (1)
- Acoustic Emission (1)
- Additive Fertigung (1)
- Additive Manufacturing (1)
- Affinity chromatography (1)
- Affinitätschromatographie (1)
- Affinitätsextraktion (1)
- Ameisensäure (1)
- Aneurism (1)
- Antibodies (1)
- Artificial weathering (1)
- BODIPY (1)
- Ball milling (1)
- Bead-based assay (1)
- Biochip (1)
- Bioconjugation (1)
- Borosilikatglas (1)
- Brightness (1)
- Bundesoberbehörden (1)
- C-C coupling (1)
- CE-ICP-MS (1)
- Carbon dot (1)
- Catch and release assay (1)
- Cell (1)
- Central Taurus (1)
- Characterization (1)
- Cleavable linker (1)
- Click chemistry (1)
- Combinatorial chemistry (1)
- Combinatorial polymer libraries (1)
- Conductometry (1)
- Conjugates (1)
- Core/shell quantum dot (1)
- Crosslinker (1)
- Crosslinking (1)
- DPA (1)
- Defect photoluminescence (1)
- Diagnostic antibodies (1)
- Dipole moment (1)
- Druckstabilität (1)
- Drug (1)
- Dual sensing (1)
- Dye degradation (1)
- Dye labeling (1)
- ELISA (1)
- EMPIR project (1)
- ESI MS (1)
- Elastin (1)
- Elemental composition (1)
- Energetic Materials (1)
- Excitation power density (1)
- Extracellualr vesicles (1)
- Extracellular matrix (1)
- Extracellular vesicles (EV) (1)
- FLIM (1)
- FPLC (1)
- FRET (1)
- FTIR (1)
- Ferumoxytol (1)
- Festphasenextraktion (1)
- Fingerprint (1)
- Flow Chemistry (1)
- Fluorescence standard (1)
- Fluorescent label (1)
- Forschungsstrategie (1)
- Friction (1)
- Fully aromatic frameworks (1)
- Gadolinium (1)
- Gallium doping (1)
- Glasmonolith (1)
- Glue (1)
- Gold nanoclusters (1)
- Graphene (1)
- HPLC (1)
- Hot steam (1)
- Human antibodies (1)
- ICP-MS (1)
- Immobilisierung (1)
- Immobilization (1)
- Immunglobulin (1)
- Immunoaffinity extraction (1)
- In situ (1)
- Inflammation (1)
- Infrared Thermography (1)
- Inline NMR Spectroscopy (1)
- Integrated Processes (1)
- Integrating sphere spectroscopy, (1)
- Iron isotope fractionation (1)
- Iron oxide (1)
- Korrelationsmatrix (1)
- LMD (1)
- LT-FCM (1)
- Laser metal deposition (1)
- Lead isotope composition (1)
- Lead-free (1)
- Legionella (1)
- Ligand (1)
- MALDI-TOF (1)
- MOF (1)
- Macrophage (1)
- Magnetic (1)
- Magnetic resonance imaging (1)
- Mass spectrometry (1)
- Massenspektrometrie (1)
- Mechanochemistry (1)
- Method comparison (1)
- Method validation (1)
- Methos comparision (1)
- Microarray (1)
- Microbially induced corrosion (1)
- Microparticle (1)
- Microparticles (1)
- Modeling (1)
- Modelling (1)
- Modular Production (1)
- Moisture (1)
- Multivariate data analysis (1)
- NDT (1)
- NIR dyes (1)
- NMR (1)
- Nanocomposite (1)
- Nanocrystal (1)
- Nanohybrid (1)
- Nanoparticle characterization (1)
- Nanotechnologie (1)
- Nd excitation (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)
- Ore provenance (1)
- Organic–inorganic nanostructures (1)
- Oxygen sensitive (1)
- PDT (1)
- PH (1)
- Paint (1)
- Peptide (1)
- Peptide Library (1)
- Peptide mass fingerprinting (1)
- Peptides (1)
- Performance validation (1)
- Perovskite (1)
- Phage Display (1)
- Phosphinine (1)
- Photocatalyst (1)
- Photoluminescence quantum yield (1)
- Photooxidation (1)
- Photostability (1)
- Polyethylene Glycol (1)
- Polyethylene glycol (1)
- Polymer particle (1)
- Polymers (1)
- Polyurethane (1)
- Porosity (1)
- Porphyrin (1)
- Precision polymer sequencing (1)
- Priam's treasure (1)
- Process Analytical Technology (1)
- Pseudo peptides (1)
- Quality assurcance (1)
- Quantum yields (1)
- Quinones (1)
- Raman spectroscopy (1)
- Reaction Monitoring (1)
- Reference material (1)
- Reference materials (1)
- Reference methods (1)
- Reference particles (1)
- Regeneration (1)
- Reverse microemulsion (1)
- SWIR photoluminescence (1)
- Saure Hydrolyse (1)
- Screening (1)
- Self-assembly (1)
- Semiconductor (1)
- Sequence-defined oligomer (1)
- Sequencing (1)
- Shape (1)
- Silica coating (1)
- Silver indium sulfide (1)
- Single cell-ICP-ToF-MS (1)
- Single molecule (1)
- Single particle-ICP-ToF-MS (1)
- Single-dot spectroscopy (1)
- Singlet oxygen (1)
- Size (1)
- Small-angle scattering (1)
- Solubilizer (1)
- Sonochemical synthesis (1)
- Speciation analysis (1)
- Stabilization (1)
- Static Mixing (1)
- Stepwise growth (1)
- Surface (1)
- Surface Chemistry (1)
- Surface analysis (1)
- Surface group (1)
- Surface group analysis (1)
- Surface group quantification (1)
- Surfaces (1)
- Suzuki-Miyaura coupling (1)
- Switch (1)
- Temperature (1)
- Therapeutic antibodies (1)
- Thick shells (1)
- Time-gated emission (1)
- Time-resolved flow cytometry (1)
- Titan-Halterung (1)
- Trastuzumab (1)
- Tribofilm (1)
- Triplet-triplet annihilation (1)
- Trojan silver artefacts (1)
- UV Vis (1)
- UpConversion (1)
- Upconverstion (1)
- Vernetzung (1)
- Wastewater (1)
- Wear (1)
- X-ray microspectroscopy (1)
- Yb(III) complex (1)
- Zirconia (1)
- anion-exchange (1)
- antibody (1)
- bacteria (1)
- bacteria detection (1)
- biokompatibel (1)
- flow cytometry (1)
- fluorescence microscopy (1)
- gesintert (1)
- immunoseparation (1)
- lifetime (1)
- magnetic nanoparticle (1)
- method (1)
- nanoparticle (1)
- pH (1)
- particle (1)
- quantum dot (1)
- quantum yield (1)
- screening tes (1)
- single cell-ICP-ToF-MS (1)
- single particle-ICP-ToF-MS (1)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (68) (entfernen)
Eingeladener Vortrag
- nein (21)
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.
Self-mated magnesia stabilized zirconia (Mg-PSZ) ceramic sliding couples have been investigated at 100 N load (P0max= 1324 MPa) in oscillating sliding conditions in different humidity conditions in air and in hot steam. Temperatures have been varied up to 400 °C and pressures up to 6 bars. The results show that the wear behavior of MgO-ZrO2 under high Hertzian contact pressures is strongly dependent on temperature and is similar for both dry oscillating and oscillating in hot steam. However, although the evolution in wear rates on temperature is similar and the wear rates of MgO-ZrO2 plunged above 300 °C in hot steam and air by nearly three orders of magnitude, SEM micrographs revealed in hot steam at 400 °C smooth wear tracks. In contrast, hot steam enhanced the tribochemistry of self-mated alumina couples and reduced wear rates. Hot steam decreased the coefficients of friction of MgO-ZrO2 with increasing temperature, but not the wear rates.
Therapeutische Antikörper sind innerhalb weniger Jahre zur wichtigsten pharmazeutischen Produktklasse aufgestiegen. Für 2023 werden weltweite Umsätze von über 200 Milliarden USD erwartet. Auch diagnostische Antikörper sind mittlerweile unverzichtbare Produkte, auf deren Basis zahllose Immunoassays und andere Schnelltests entwickelt wurden. Neben der bereits sehr aufwendigen Herstellung von Antikörpern ist deren Aufreinigung aus komplexen Zellkulturmedien oder Blutseren und -plasmen zu einem Engpass in der Produktion und Nutzung dieser komplexen Proteine geworden. Schnelle und einfache Reinigungsmethoden für Antikörper sind daher sehr gefragt.
Yb,Nd,Er-doped upconversion nanoparticles (UCNPs) have attracted considerable interest as luminescent reporters for bioimaging, sensing, energy conversion/shaping, and anticounterfeiting due to their capability to convert multiple near-infrared (NIR) photons into shorter wavelength ultraviolet, visible or NIR luminescence by successive absorption of two or more NIR photons. This enables optical measurements in complex media with very little background and high penetration depths for bioimaging. The use of Nd3+ as substitute for the commonly employed sensitizer Yb3+ or in combination with Yb3+ shifts the excitation wavelength from about 980 nm, where the absorption of water can weaken upconversion luminescence, to about 800 nm, and laser-induced local overheating effects in cells, tissue, and live animal studies can be minimized. To systematically investigate the potential of Nd3+ doping, we assessed the performance of a set of similarly sized Yb3+,Nd3+,Er3+-doped core- and core–shell UCNPs of different particle architecture in water at broadly varied excitation power densities (P) with steady state and time-resolved fluorometry for excitation at 980 nm and 808 nm. As a measure for UCNPs performance, the P-dependent upconversion quantum yield (Φ) and its saturation behavior were used as well as particle brightness (B). Based upon spectroscopic measurements at both excitation wavelengths in water and in a lipid phantom and B-based calculations of signal size at different penetration depths, conditions under which excitation at 808 nm is advantageous are derived and parameters for the further optimization of triple-doped UCNPs are given.
In Vivo Biotransformations of Indium Phosphide Quantum Dots Revealed by X‑Ray Microspectroscopy
(2019)
Many attempts have been made to synthesize cadmium-free quantum dots
(QDs), using nontoxic materials, while preserving their unique optical properties. Despite impressive advances, gaps in knowledge of their intracellular fate, persistence, and excretion from the targeted cell or organism still exist, precluding clinical applications. In this study, we used a simple model organism (Hydra vulgaris) presenting a tissue grade of organization to determine the biodistribution of indium phosphide (InP)-based QDs by X-ray fluorescence imaging. By complementing elemental imaging with In L-edge X-ray absorption near edge structure, unique information on in situ chemical speciation was obtained. Unexpectedly, spectral profiles indicated the appearance of In−O species within the first hour post-treatment, suggesting a fast degradation of the InP QD core in vivo, induced mainly by carboxylate groups. Moreover, no significant difference in the behavior of bare core QDs and QDs capped with an inorganic Zn(Se,S) gradient shell was observed. The results paralleled those achieved by treating animals with an equivalent dose of indium salts, confirming the preferred bonding type of In3+ ions in Hydra tissues. In conclusion, by focusing on the chemical identity of indium along a 48 h long journey of QDs in Hydra, we describe a fast degradation process, in the absence of evident toxicity. These data pave the way to new paradigms to be considered in the biocompatibility assessment of QD-based biomedical applications, with greater emphasis on the dynamics of in vivo biotransformations, and suggest strategies to drive the design of future applied materials for nanotechnology-based diagnosis and therapeutics.
With the goal to improve their photostability, InP-based QDs are passivated with three types of inorganic shells, namely (i) a gradient ZnSexS1−x shell, (ii) an additional ZnS shell on top of the gradient shell with two different thicknesses (core/shell/shell, CSS), (iii) an alumina coating on top of ZnS. All three systems have photoluminescence Quantum yields (PLQY) > 50%and similar PL decay times (64–67 ns). To assess their photostability they are incorporated into a transparent poly (methyl methacrylate) (PMMA) matrix and exposed to continuous irradiation with simulated sunlight in a climate chamber. The alumina coated core/shell system exhibits the highest stability in terms of PLQY Retention as well as the lowest shift of the PL maximum and lowest increase of the PL linewidth, followed by the CSS QDs and finally the gradient shell system. By means of XPS studies we identify the degradation of the ZnS outer layer and concomitant xidation of the emissive InZnP core as the main origins of degradation in the gradient structure. These modifications do not occur in the case of the alumina-capped sample, which exhibits excellent chemical stability. The gradient shell and CSS systems could be transferred to the aqueous phase using surface ligand exchange with penicillamine. Cytotoxicity studies on human primary keratinocytes revealed that exposure for 24 h to 6.25–100 nM of QDs did not affect cell viability. However, a trend toward reduced cell proliferation is observed for higher concentrations of gradient shell and CSS QDs with a thin ZnS shell, while CSS QDs with a thicker ZnS shell do not exhibit any impact.
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).
Lead isotopes are a well-established tool to trace the geographic origin of samples and artefacts in archaeology and geochemistry. In archaeology, lead isotopes are often applied to gain information on the provenance of the used ores especially in lead and silver artefacts. The assignment of a specific and unambiguous provenance in most cases is not possible or at least hindered due to several limitations such as ore deposits overlapping in their lead isotopic composition, a large spread within one ore deposit or a missing overlap with known mining sites. Such difficult cases can only be solved by using information from sources being independent of the isotope data. This information can be of chemical nature such as concentrations of key elements or they can be of archaeological nature such as cultural or trade route information.Within this study, we combined lead isotope data of ores and artefacts with silver mass fractions in the ore deposits, Au/Ag-ratios in ores and artefacts and finally archaeological Information on the cultural context in the Mediterranean and Anatolian Region. This approach enabled us to significantly reduce the potential number of mining regions. Finally, the potential sources could be narrowed down to the three remaining locations the Central Taurus, Arap Dağ and the Eastern Troad. Beneath these three locations, the Central Taurus shows the highest probability for the geographic origin of the galena which has been used to create the Trojan silver artefacts.
What isotopes can do...
(2019)
Im Vergleich zu anderen Proteinen ist die Identifizierung von Antikörpern anhand ihrer Sequenz zum Beispiel mittels "peptide mass fingerprinting" schwierig. Da die Sequenzinformation eines Antikörpers aufgrund der hypersomatischen Mutation während der Affinitätsreifung nicht im Genom eines Organismus gespeichert ist, kann die Aminosäuresequenz nicht auf einfachem Weg der DNA-Sequenzierung gewonnen werden. Das ist nur in seltenen Fällen möglich, wenn dem Endanwender der Zellklon der Antikörper-produzierenden Zelle zugänglich ist. Eine Sequenzierung auf Protein-Ebene ist sehr aufwändig und teuer und wird daher fast nie für die Charakterisierung von analytischen Antikörpern verwendet. Der Mangel an Validierung dieser analytischen Antikörper, die bei Experimenten verwendeten werden, löst aber eine Reihe Probleme aus, die die Wiederholbarkeit dieser Experimente schwierig und in einigen Fällen unmöglich macht. Das sorgt jährlich für verschwendete Forschungsgelder in Milliardenhöhe und hindert den wissenschaftlichen Fortschritt.
Ziel der vorliegenden Arbeit war die Entwicklung einer einfachen und schnellen Methode, die es trotzdem ermöglicht, die Identifikation von Antikörpern sicherzustellen. Dazu wurde eine Methode basierend auf dem "peptide mass fingerprinting" gewählt. Das Problem der unbekannten Aminosäuresequenz der Antikörper wurde gelöst, indem lediglich die Peptidmuster der entstehenden Fingerprint-Spektren zur Identifikation herangezogen wurden. MALDI wurde dabei als Ionisationsmethode für die Massenspektrometrie gewählt, da die resultierenden Spektren im Gegensatz zu ESI-MS einfach auszuwerten sind. Auch kann auf eine vorige Trennung der Peptide mittels LC verzichtet werden, was zusätzlich Analysenzeit spart. Für die Proteinspaltung wurde eine simple saure Hydrolyse mittels Ameisensäure gewählt. Im Vergleich zum herkömmlichen Trypsin-Verdau konnten auf zeitraubende Arbeitsschritte wie Denaturierung, Reduktion und Alkylierung der Antikörper verzichtet werden. Die Hydrolyse mittels Ameisensäure wurde bisher nur auf kleine und mittelgroße Proteine angewendet, sodass im ersten Teil dieser Arbeit mehrere Schritte optimiert wurden bevor zufriedenstellende Fingerprint-Spektren von Antikörpern erhalten wurden.