TY - JOUR A1 - Schwarz, G. A1 - Müller, Larissa A1 - Beck, S. A1 - Linscheid, M.W. T1 - DOTA based metal labels for protein quantification: a review N2 - Today, quantitative data play a pivotal role in the understanding of biological processes. This is particularly true for the proteome: protein quantification always follows protein identification. To obtain useful and reliable quantitative data, rather sophisticated strategies using electrospray and MALDI mass spectrometry have been developed, which allow relative and sometimes even absolute quantification. All of those strategies have merits and limitations. In order to overcome some of these limits, methods based on the reliable and sensitive detection and quantification of heavy metals present in proteins using inductively coupled plasma (ICP)-MS have been reported. With specific labels carrying heavy metals, the applicability of ICP-MS has been extended to almost every protein. One of such covalently bound metal tags, allowing the quantification of low abundant proteins, uses 1,4,7,10-tetraazacyclododecane N,N',N'',N''-tetraacetic acid (DOTA) chelate complexes carrying lanthanides as the metal core. In this review the scope and limitations of peptide and protein quantification will be addressed. The metal tags do not only provide low detection limits, but also due to the large number of different lanthanides and lanthanide isotopes, multiplexing capabilities and previously unknown accuracy based on inherently possible isotope dilution methods came into reach. The developed workflows, including electrophoretic and chromatographic separation and preconcentration techniques, will be addressed to allow a comparison with already established procedures. KW - Protein quantification KW - ICP-MS KW - DOTA KW - Labeling PY - 2014 DO - https://doi.org/10.1039/c3ja50277e SN - 0267-9477 SN - 1364-5544 VL - 29 IS - 2 SP - 221 EP - 233 PB - Royal Society of Chemistry CY - London AN - OPUS4-30730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Mairinger, T. A1 - Hermann, G. A1 - Koellensperger, G. A1 - Hann, S. T1 - Characterization of metal-tagged antibodies used in ICP-MS-based immunoassays N2 - A detailed characterization of metal-tagged antibodies is the prerequisite for the implementation of quantitative concepts in inductively coupled plasma–mass spectrometry (ICP-MS)-based bioanalysis or future medical diagnosis. In this paper, the common modification with bifunctional ligands containing maleimide residues as a reactive group was investigated in detail via size exclusion chromatography (SEC)-ICP-MS and liquid chromatography–time-of-flight (LC-TOF)-MS to determine the preservation of the antibody structure after tagging. Mouse monoclonal IgG modified with metal-coded tags (MeCATs) was used as a model system. Several antibody fragments were identified carrying different numbers of metal tags. In a second step, a functionality test was performed with isolated fragments where the antigen specificity was tested in a dot blot immunoassay. KW - Bioanalytical methods KW - Mass spectrometry KW - ICP-MS KW - Antibody tagging KW - Antibodies KW - Immunoassay KW - Maleimide DOTA KW - Tags PY - 2014 DO - https://doi.org/10.1007/s00216-013-7416-x SN - 1618-2642 SN - 1618-2650 VL - 406 IS - 1 SP - 163 EP - 169 PB - Springer CY - Berlin AN - OPUS4-30037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirilina, E. A1 - Helbling, S. A1 - Morawski, M. A1 - Pine, K. A1 - Reimann, K. A1 - Jankuhn, S. A1 - Dinse, J. A1 - Deistung, A. A1 - Reichenbach, J. R. A1 - Trampel, R. A1 - Geyer, S. A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Arendt, T. A1 - Bazin, P.-L. A1 - Weiskopf, N. T1 - Superficial white matter imaging: Contrast mechanisms and whole-brain in vivo mapping N2 - 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. KW - Magnetic resonance imaging KW - Laser ablation KW - ICP-MS KW - Brain KW - Imaging PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514430 DO - https://doi.org/10.1126/sciadv.aaz9281 SN - 2375-2548 VL - 6 IS - 41 SP - eaaz9281 PB - American Association for the Advancement of Science (Science/AAAS) CY - Washington, DC, USA AN - OPUS4-51443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giesen, C. A1 - Müller, Larissa A1 - Panne, Ulrich A1 - Jakubowski, Norbert T1 - History of inductively coupled plasma mass spectrometry-based immunoassays N2 - The analysis of biomolecules requires highly sensitive and selective detection methods capable of tolerating a complex, biological matrix. First applications of biomolecule detection by ICP-MS relied on the use of heteroelements as a label for quantification. However, the combination of immunoassays and ICP-MS facilitates multiparametric analyses through elemental tagging, and provides a powerful alternative to common bioanalytical methods. This approach extends the detection of biomarkers in clinical diagnosis, and has the potential to provide a deeper understanding of the investigated biological system. The results might lead to the detection of diseases at an early stage, or guide treatment plans. Immunoassays are well accepted and established for diagnostic purposes, albeit ICP-MS is scarcely applied for the detection of immune-based assays. However, the screening of biomarkers demands high throughput and multiplex/multiparametric techniques, considering the variety of analytes to be queried. Finally, quantitative information on the expression level of biomarkers is highly desirable to identify abnormalities in a given organism. Thus, it is the aim of this review to introduce the fundamentals, and to discuss the enormous strength of ICP-MS for the detection of different immunoassays on the basis of selected applications, with a special focus on LA-ICP-MS. KW - ICP-MS KW - LA-ICP-MS KW - Immunoassay KW - Elemental tagging KW - Multiplexing PY - 2012 DO - https://doi.org/10.1016/j.sab.2012.06.009 SN - 0584-8547 SN - 0038-6987 N1 - Geburtsname von Müller, Larissa: Wäntig, L. - Birth name of Müller, Larissa: Wäntig, L. VL - 76 SP - 27 EP - 39 PB - Elsevier CY - Amsterdam AN - OPUS4-27686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -