PL06

Microanalysis of biological materials by X-ray and plasma-based techniques

Zoltán Sávoly a, Zsófia Polgári a, Andrea Réti b, Christina Streli c, Peter Kregsamer c, Norbert Szoboszlai a, István Péter Nagy d and Gyula Záray a,* a Laboratory of Environmental Chemistry and Bioanalytics, Department of Analytical Chemistry, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/A; b Department of Clinical Research, National Institute of Oncology, H-1122, Budapest, Ráth György u. 7-9., Hungary; cAtominstitut of the Austrian Universities, TU-Wien, Stadionallee 2, A-1020, Vienna, Austria; d Department of Zoology and Ecology, Szent István University, Gödöll ő, Hungary *E-mail: [email protected]

The use of atom spectroscopic methods in service of biological and clinical sample analysis is gaining an increasing importance day by day opening new horizons for interdisciplinary investigations aiming at the better understanding of the world that surrounds us and its physiological processes. For example, it is hard to believe that four of each five multicellular animals on earth are nematodes. There are herbivore, bacterivore, fungivore, omnivore nematodes and predators, too. They may occur in freshwater, seawater and soil (free-living nematodes), or they can be parasites as well. A fistful of soil contains thousands of nematodes. Nematode communities were proved to be a good bioindicator for environmental monitoring. The effect of certain microelements on nematode communities is widely studied; however there is relatively little information on the investigation of elemental composition of nematodes. Therefore, at first, two different methods were developed for the determination of the trace element content of nematodes: total-reflection X-ray fluorescence (TXRF) spectrometry for single species analysis and inductively coupled sector field plasma mass spectrometry (ICP-SF-MS) after vapor-phase microwave-assisted digestion with nitric acid of about 500 nematodes corresponding to the bulk analysis. The K, Ca, Fe, Cu and Zn content of the single species could be determined by TXRF. The trace element content of the digested samples was determined by means of ICP-SF-MS spectrometry. On the other hand, the effect of CuSO 4 - a popular fungicide used for cultivar spraying - on nematodes was studied by exposing them to different concentrations of CuSO 4 solutions. The distribution of Cu and some essential elements was investigated by synchrotron radiation at BESSY beamline (Helmholtz Zentrum, Berlin, Germany). In this way, typical hotspots of the above-mentioned elements could be detected in the body of nematodes. Iron is an essential component of many proteins and enzymes that are involved in cell growth and replication, thus is intensively investigated. The most important research topics are: i) regulation of absorption of heme and non-heme iron; ii) regulation of iron transport proteins; iii) metabolism of iron in cells; iv) the role of iron in cell cycle control; v) role of iron in cancer angiogenesis and metastasis development. Cancer cells are more sensitive to iron depletion than normal cells; accordingly, iron chelators are investigated in clinical trials as new anticancer drugs. Iron uptake and depletion can be investigated by different analytical techniques. Thus, Fe, Cu and Zn in HCA-7 and HT-29 human colorectal cancer cells treated with different iron compounds (FeCl 3, Fe(III) citrate and FeSO 4) and iron chelators like EDTA could be determined by TXRF. Sample handling and preparation for these minute samples are crucial steps, thus special attention has to be paid during the sample preparation.

The financial support of Hungarian Research Fund through Grant 81401 is hereby acknowledged.