Chemische Charakterisierung und Spurenanalytik
Filtern
Erscheinungsjahr
- 2020 (5) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (4)
- Vortrag (1)
Sprache
- Englisch (5)
Schlagworte
- ICP-MS (5) (entfernen)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (1)
Superficial white matter (SWM) contains the most cortico-cortical white matter connections in the human brain encompassing the short U-shaped association fibers. Despite its importance for brain connectivity, very little is known about SWM in humans, mainly due to the lack of noninvasive imaging methods. Here, we lay the groundwork for systematic in vivo SWM mapping using ultrahigh resolution 7 T magnetic resonance imaging. Using biophysical modeling informed by quantitative ion beam microscopy on postmortem brain tissue, we demonstrate that MR contrast in SWM is driven by iron and can be linked to the microscopic iron distribution. Higher SWM iron concentrations were observed in U-fiber–rich frontal, temporal, and parietal areas, potentially reflecting high fiber density or late myelination in these areas. Our SWM mapping approach provides the foundation for systematic studies of interindividual differences, plasticity, and pathologies of this crucial structure for cortico-cortical connectivity in humans.
This tutorial review article is highlighting the fundamentals, instrumentation, and most recent trends of single-cell analysis by use of inductively coupled plasma-mass spectrometry (ICP-MS). It is shown that metals and hetero-elements being intrinsically present in cells, taken up by cells (for instance engineered metallic nanoparticles) or binding to a cell can be detected qualitatively by existing ICP-MS Technologies on a single cell level. Adding a quantitative dimension to single-cell analysis by (laser ablation-) ICP-MS requires dedicated calibration and validation strategies, which are currently being established and are being critically discussed. In a tutorial part, the ICP-MS instruments, the measurement conditions, and the sample introduction and preparation techniques are introduced. The application section focuses on the state-of-the-art of single-cell analysis in suspension, using laser ablation or (imaging) mass cytometry. Finally, future trends are critically assessed.
Well-absorbed iron-based nanoparticulated materials are a promise for the oral management of iron deficient anemia. In this work, a battery of in vitro and in situ experiments are combined for the evaluation of the uptake, distribution and toxicity of new synthesized ultrasmall (4 nm core) Fe2O3 nanoparticles coated with tartaric/adipic acid with potential to be used as oral Fe supplements. First, the in vitro simulated gastric acid solubility studies by TEM and HPLC-ICP-MS reveal a partial reduction of the core size of about 40% after 90 min at pH3. Such scenario confirms the arrival of the nanoparticulate material in the small intestine. In the next step, the in vivo absorption through the small intestine by intestinal perfusion experiments is conducted using the sought nanoparticles in Wistar rats. The quantification of Fe in the NPs Suspension before and after perfusion shows Fe absorption levels above 79%, never reported for other Fe treatments. Such high absorption levels do not seem to compromise cell viability, evaluated in enterocytes-like models (Caco-2 and HT-29) using cytotoxicity, ROS production, genotoxicity and lipid peroxidation tests. Moreover, regional differences in terms of Fe concentration are obtained among different parts of the small intestine as duodenum>jejunum>ileum. Complementary transmission electron microscopy (TEM) images show the presence of the intact particles around the intestinal microvilli without significant tissue damage. These studies show the high potential of these NP preparations for their use as oral management of anemia.
In this investigation, two conventional peristaltic pumps are compared with a new pump based on the “easy click” principle using a simultaneous ICP-AES instrument with standard operating conditions. It is found that the figures of merit achieved are quite comparable for all three pumps. Relative standard deviations (RSDs) range between 0.2% and 1.8%, and limits of detection as low as 0.1 μg/L have been achieved , demonstrating that the easy click principle of the new pump does not compromise the analytical figures of merit.
Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful method for the matrix-independent quantitative analysis of target elements. Developed for the use in inorganic trace analysis, ICP-MS is nowadays a valuable tool for bioanalytical questions. Especially the use of ICP-MS for quantitative proteomics by measuring heteroatoms has gained recognition in the last decade, considering that established quantification methods like organic mass spectrometry depend on labelling of the target protein or the existence of matched protein and peptide standards. The need for reliable quantification of proteins is continuously growing, but only a limited number of well-characterized and quantified protein standards are available so far. Accurately quantified, traceable protein standards are necessary to ensure comparability of measurements between laboratories, not only in basic research but also in a clinical context. One example of this is the Alzheimer’s disease biomarker tau protein. However, existing tau standards lack comparability, emphasizing the need for a well-quantified protein standard.
Therefore, we developed a method for the quantification of pure proteins via sulfur isotope dilution ICP-MS (IDMS). As sulfur is present in two amino acids, cysteine and methionine, it exists in nearly all proteins and can be used for the quantification of proteins of known stoichiometry. We employed simple offline strategies for the separation of non-protein bound sulfur species. Quantification of these contaminations by IDMS allows for correction of the protein content and enables reliable protein quantification. We report the protein mass fractions of a standard reference material and commercially available proteins determined by sulfur IDMS, including the expanded uncertainties. The developed method can be applied for the reliable and traceable quantification of pure proteins for use as in-house standards. Here, we successfully used this method for the quantification of the tau protein.