TY - JOUR A1 - Hoesl, Simone A1 - Neumann, B. A1 - Techritz, Sandra A1 - Sauter, G. A1 - Simon, R. A1 - Schlüter, H. A1 - Linscheid, M. W. A1 - Theruing, F. A1 - Müller, Larissa A1 - Jakubowski, Norbert T1 - Internal standardization of LA-ICP-MS immunoimaging via printing of universal metal spiked inks onto tissue sections JF - Journal of analytical atomic spectrometry N2 - Formalin-fixed paraffin-embedded (FFPE) specimen from biopsy materials are a widespread sample format for pathologists and medical researchers. Pathologists are archiving vast numbers of FFPE samples which can be stored for decades. Conventional immunohistochemical staining (IHC) of biomarkers on FFPE tissue sections is one of the most important analytical techniques for cancer diagnosis and pathology in general. However standardization for IHC samples and quality management is tedious and differs significantly from clinic to clinic. Combining established IHC staining strategies with modern mass spectrometry mediated methods would increase it`s potential and enable access of large FFPE archives for multiplexed quantitation purposes. In this work element mass spectrometry and a new ink-jet printed internal standardization approach was successfully combined with IHC staining to facilitate quantitative multiplex assays for archived FFPE samples. The printing strategy improves elemental image resolution and reproducibility of paraffin embedded breast cancer tissue sections in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using conventional IHC staining as a model system to investigate the new capabilities of this technique. For the internal standardization we applied a conventional CD-ink-jet printer to print a metal spiked ink onto the top of thin layer tissue sections with constant density. Printing was carried out in a direct comparison to an iodination of the tissue section as previously described as an alternative standardization method. The use of the printed internal standard allowed correction of the fluctuation during the laser ablation process and compensated instrumental drift effects. Mediated by the ink correction approach we achieved better signal-to-background-ratios (SBR) of 74 and better spatial resolution of 30 µm compared to iodination (SBR=23). This improved performance was demonstrated on tumorous areas in FFPE breast cancer tissue sections and allowing detection of Her-2 in tumorous areas of this tissue with significantly improved contrast. KW - Internal standardization KW - LA-ICP-MS KW - Immuno imaging PY - 2016 DO - https://doi.org/10.1039/c5ja00409h SN - 0267-9477 SN - 1364-5544 VL - 31 IS - 3 SP - 801 EP - 808 AN - OPUS4-35711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hösl, Simone A1 - Neumann, B. A1 - Techritz, Sandra A1 - Linscheid, M. A1 - Theuring, F. A1 - Scheler, C. A1 - Jakubowski, Norbert A1 - Müller, Larissa T1 - Development of a calibration and standardization procedure for LA-ICP-MS using a conventional ink-jet printer for quantification of proteins in electro- and western-blot assays JF - Journal of analytical atomic spectrometry N2 - We developed new procedures for internal standardization and calibration to be used for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for elemental micro mapping imaging of biological samples like Western blot membranes and tissue sections. These procedures are based on printing of metal spiked inks onto the top of thin layer samples for simultaneous internal standardization and calibration of LA-ICP-MS. In the case of internal standardization the ink is spiked with indium as an internal standard and homogenously printed over the entire membrane (size 56 cm2) prior to LA-ICP-MS detection, a standard deviation (RSD) value of 2% was achieved. In the second approach the metal content of lanthanide tagged proteins and antibodies after biological work flows was quantified by LA-ICP-MS on nitro-cellulose membranes. In this case the inks spiked with varying metals were printed with different densities on the same nitrocellulose membranes in well-defined squares to produce matrix-matched calibration standards. For validation and calibration the ink squares were excised and the specific metal content was measured by liquid ICP-MS after solubilization of the membrane slice. For the printed calibration standard limits of detection (LOD) of <4 fmol for different metals and relative process standard deviations of 1–2% only were determined via LA-ICP-MS. PY - 2014 DO - https://doi.org/10.1039/c4ja00060a SN - 0267-9477 SN - 1364-5544 VL - 29 IS - 7 SP - 1282 EP - 1291 PB - Royal Society of Chemistry CY - London AN - OPUS4-31171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -