Quantitative Bioimaging of Platinum in Tissues

For LA-ICP-MS measurements, tumor and kidney samples were embedded in Tissue-Tek medium and cryosectioned into slices of 20 μm thickness with a cryotom (Microm HM 550, Thermo Fisher). Quantitative bioimaging by LA-ICP-MS was performed according to a previously described procedure, using matrix-matched calibration standards.^{29 (link)} A Nd:YAG solid state laser (NWR 213, ESI, Fremont, CA, USA) at a wavelength of 213 nm was used to obtain the spatially-resolved distribution of platinum in tumor and kidney sections. Laser ablation was performed as described previously.^{9 (link)} Data were recorded by using a Triple Quadrupole ICP-MS Agilent 8800 instrument (Agilent Technologies, Tokyo, Japan) and processed with the Agilent MassHunter software package (Workstation Software, Version B.01.03, 2013). The software Igor Pro (Wavemetrics, Igor Pro 6.34A) together with its add-on Iolite (Iolite Version 2.5) was used for further data processing and generation of platinum distribution maps.^{30 (link)}