TY - JOUR A1 - Abbas, Ioana M. A1 - Vranic, M. A1 - Hoffmann, Holger A1 - El-Khatib, Ahmed H. A1 - Montes-Bayón, M. A1 - Möller, H. M. A1 - Weller, Michael G. T1 - Investigations of the copper peptide hepcidin-25 by LC-MS/MS and NMR (+) N2 - Hepcidin-25 was identified as the main iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry (MS/MS), high-resolution mass spectrometry HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D)model of hepcidin-25with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others. KW - Metalloprotein KW - Peptide KW - Chromatography KW - High pH KW - Mobile phase KW - Metrology KW - Purity KW - Reference material KW - ATCUN KW - Copper KW - Nickel PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457796 UR - http://www.mdpi.com/1422-0067/19/8/2271 DO - https://doi.org/10.3390/ijms19082271 SN - 1422-0067 VL - 19 IS - 8 SP - 2271, 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-45779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chronakis, Michail Ioannis A1 - Mavrakis, E. A1 - Alvarez-Fernandez García, R. A1 - Montes-Bayon, M. A1 - Bettmer, J. A1 - Pitta, P. A1 - Tsapakis, M. A1 - Kalantzi, I. A1 - Tsiola, A. A1 - Pergantis, S. An. T1 - Investigating the behavior of ultratrace levels of nanoparticulate and ionic silver in a seawater mesocosm using single particle inductively coupled plasma – mass spectrometry N2 - Silver nanoparticles (AgNPs) nowadays appear in close to 24% of consumer products that contain engineered nanomaterials. Thus, they are expected to be released into the environment, where their fate and effect are still undetermined. Considering the evidenced efficacy of the single particle Inductively Coupled Plasma – Mass Spectrometry (sp ICP-MS) technique in the study of nanomaterials, this work reports on the use of sp ICP-MS along with an online dilution sample introduction system for the direct analysis of untreated and spiked seawater samples, as part of a larger scale experiment studying the fate of Ag (ionic and nanoparticles) in seawater mesocosm systems. Silver nanoparticles coated with branched polyethyleneimine (BPEI@AgNPs) or ionic silver (Ag+) were introduced gradually into the seawater mesocosm tanks at very low, environmentally relevant concentrations (50 ng Ag L− 1 per day, for 10 consecutive days, up to a total of 500 ng Ag L− 1 ), and samples were collected and analyzed daily, within a consistent time window. Using very low detector dwell time (75 μs) and specialized data treatment, information was obtained on the nanoparticles’ size distribution and particle number concentration, as well as the ionic silver content, of both the AgNPs and the Ag+ treated seawater mesocosm tanks. The results for the AgNP treated samples indicated the rapid degradation of the added silver particles, and the subsequent increase of ionic silver, with recoveries close to 100% for the first days of the experiment. On the other hand, particle formation was observed in the Ag+ treated seawater tanks, and even though the number concentration of silver-containing nanoparticles increased throughout the experiment, the amount of silver per particle remained relatively constant from the early days of the experiment. In addition, the online dilution sample introduction system for the ICP-MS proved capable of handling the untreated seawater matrix without significant contamination issues and downtime, while the low dwell time and data treatment procedure developed were shown to be suitable for the analysis of nanomaterials at the low nm-scale, despite the complex and heavy matrix introduced into the ICP-MS. KW - Mesocosm KW - Single-particle KW - Seawater PY - 2023 DO - https://doi.org/10.1016/j.chemosphere.2023.139109 VL - 336 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-57814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abbas, Ioana M. A1 - Hoffmann, Holger A1 - Montes-Bayón, M. A1 - Weller, Michael G. T1 - Improved LC-MS/MS method for the quantification of hepcidin-25 in clinical samples N2 - Mass spectrometry-based methods play a crucial role in the quantification of the main iron metabolism regulator hepcidin by singling out the bioactive 25-residue peptide from the other naturally occurring N-truncated isoforms (hepcidin-20, -22, -24), which seem to be inactive in iron homeostasis. However, several difficulties arise in the MS analysis of hepcidin due to the sticky character of the peptide and the lack of suitable standards. Here, we propose the use of amino- and fluoro-silanized autosampler vials to reduce hepcidin interaction to laboratory glassware surfaces after testing several types of vials for the preparation of stock solutions and serum samples for isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). Furthermore, we have investigated two sample preparation strategies and two chromatographic separation conditions with the aim of developing an LC-MS/MS method for the sensitive and reliable quantification of hepcidin-25 in serum samples. A chromatographic separation based on usual acidic mobile phases was compared with a novel approach involving the separation of hepcidin-25 with solvents at high pH containing 0.1% of ammonia. Both methods were applied to clinical samples in an intra-laboratory comparison of two LC-MS/MS methods using the same hepcidin-25 calibrators with good correlation of the results. Finally, we recommend an LC-MS/MS-based quantification method with a dynamic range of 0.5–40 μg/L for the assessment of hepcidin-25 in human serum that uses TFA-based mobile phases and silanized glass vials. KW - HPLC KW - Liquid chromatography KW - Mass spectrometry KW - Silanization KW - Mobile phase KW - Adsorption KW - Peptide losses KW - Recovery KW - Validation KW - Quality control KW - QC KW - Iron disorders KW - Chronic kidney disease KW - Metrology KW - Round robin exercise KW - Basic solvent KW - Peptide analysis PY - 2018 DO - https://doi.org/10.1007/s00216-018-1056-0 SN - 1618-2642 SN - 1618-2650 VL - 410 IS - 16 SP - 3835 EP - 3846 PB - Springer Nature CY - Heidelberg AN - OPUS4-45053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García Fernández, J. A1 - Sánchez-González, C. A1 - Bettmer, J. A1 - Llopi, J. A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Montes-Bayón, M. T1 - Quantitative assessment of the metabolic products of iron oxide nanoparticles to be used as iron supplements in cell cultures N2 - Iron nanoparticles (NPs) metabolism is directly associated to human health due to their use as anemia treatment and should be studied in detail in cells. Here we present a speciation strategy for the determination of the metabolic products of iron oxide nanoparticles coated by tartaric and adipic acids in enterocytes-like cell models (Caco-2 and HT-29). Such methodology is based on the use of SDS-modified reversed phase high performance liquid chromatography (HPLC) separation using inductively coupled plasma-mass spectrometry (ICP-MS) as Fe selective detector. Post-column isotope dilution analysis is used as quantification tool by adding Fe-57 as isotopically enriched standard. To assess the separation capability of the method, two different iron nanostructures: iron sucrose nanoparticles -Venofer®- used as model suspension and iron tartrate/adipate-modified nanoparticles, both of about 4 nm (core size) were evaluated. The two nanostructures were injected into the system showing good peak profiles and quantitative elution recoveries (>80%) in both cases. In addition, both nanoparticulate fractions could be based-line separated from ionic iron species, which needed to be complexed with 1mM citrate to elute from the column. Exposed cells up to 0.5mM of iron tartrate/adipate-modified nanoparticles were specifically treated to extract the internalized NPs and the extracts examined using the proposed strategy. The obtained results revealed the presence of three different fractions corresponding to nanoparticle aggregates, dispersed nanoparticles and soluble iron respectively in a single chromatographic run. Quantitative experiments (column recoveries ranging from 60 to 80%) revealed the presence of the majority of the Fe in the nanoparticulated form (>75%) by summing up the dispersed and aggregate particles. Such experiments point out the high uptake and low solubilization rate of the tartrate/adipate NPs making these structures highly suitable as Fe supplements in oral anemia treatments. KW - Fe nanoparticles metabolism KW - Cells KW - HPLC-ICP-MS KW - Species-unspecific on-line isotope dilution PY - 2018 DO - https://doi.org/10.1016/j.aca.2018.08.003 SN - 0003-2670 VL - 1039 SP - 24 EP - 30 PB - Elsevier CY - Amsterdam AN - OPUS4-46817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Garcia-Fernandez, J. A1 - Turiel, D. A1 - Bettmer, J. A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Rivas Garcia, L. A1 - Llopis, J. A1 - Sanchez-Gonzalez, C. A1 - Montes-Bayon, M. T1 - In vitro and in situ experiments to evaluate the biodistribution and cellular toxicity of ultrasmall iron oxide nanoparticles potentially used as oral iron supplements N2 - 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. KW - Iron nanoparticles KW - Anemia KW - ICP-MS KW - In vitro KW - In situ PY - 2020 DO - https://doi.org/10.1080/17435390.2019.1710613 VL - 14 IS - 3 SP - 388 EP - 403 PB - Taylor & Francis Online CY - London AN - OPUS4-50314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García-Fernández, J. A1 - Bettmer, J. A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Añón, E. A1 - Montes-Bayón, M. A1 - Sanz-Medel, A. T1 - The fate of iron nanoparticles used for treatment of iron deficiency in blood using mass-spectrometry based strategies N2 - The release of iron from iron nanoparticles (NPs) used as parenteral formulations appears to be influenced by the size and surface properties of the colloidal iron complex and the matrix. A clinically applied product Venofer® has been used as a model formulation to establish adequate analytical strategies to evaluate the fate of iron nanoparticles (NPs) in blood. First, the preparation was characterized by high resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS) and UV-vis absorption spectroscopy. This revealed the presence of monodisperse iron NPs with a hydrodynamic diameter of ∼15 nm and an iron core of ∼4 nm. Venofer® was then incubated with serum and whole blood in a quantitative study on the iron bioavailability from these NPs. Iron was speciated and quantified by using inductively coupled plasma mass spectrometry (ICP-MS). Iron solubilization levels of up to 42% were found in both fluids using isotope dilution of iron for quantification within the first hour of incubation even in the absence of the reticuloendothelial system. The monitoring of the iron-containing proteins present in serum was conducted by highperformance liquid chromatography with ICP-MS detection. It indicated that the dissolved iron ions are bound to transferrin. Quantitative speciation studies using isotope pattern deconvolution experiments concluded that the released iron saturated almost completely (up to 90%) the metal binding sites of transferrin. The remaining iron appeared also associated to albumin and, to a lesser extent, forming smaller sized particles. Thus, the methods presented here provide new insights into the fate of Venofer® nanoparticles and may be applied to other formulations. KW - Iron-sucrose nanoparticles KW - Serum KW - Bioavailability KW - Speciation KW - HPLC KW - ICP-MS PY - 2017 DO - https://doi.org/10.1007/s00604-017-2388-8 SN - 0026-3672 SN - 1436-5073 VL - 184 IS - 10 SP - 3673 EP - 3680 AN - OPUS4-43128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -