STEM in SEM imaging of gold nanoparticles in tissular ecotoxicity experiments
| Autor: | García-Negrete, C. A., Jiménez de Haro, María del Carmen, Blasco, Julián, Soto, Manu, Fernández-Camacho, A. |
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| Přispěvatelé: | Junta de Andalucía, European Commission |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Trabajo presentado en el 18th International Microscopy Congress (IMC-2014), celebrado enn Praga del 7 al 12 dse septiembre de 2014 Because of their prospective widespread use, gold nanoparticles (AuNPs) will certainly accountfor a considerable and persistent nanomaterial input to environmental systems. Thereforeecotoxicological risks in non target organisms associated with AuNPs are showing increasingconsideration. Location of AuNPs has been previously studied in our laboratory analyzing slicesof gills and digestive gland tissues of the bivalbe Ruditapes philippinarum after “in vivo”exposure experiments. Analysis was carried out by TEM of ultrathin tissue’s slices (80 nm)operating at 80 kV [1].In this communication we present the results of investigating the use of an “in vitro”methodology associated to the optimization of the STEM-in-SEM technique for the use of ascanning electron microscope (SEM-FEG) in transmission mode and operated at 20-30 kV.The advantages of STEM-in-SEM over TEM are discussed [2, 3]. The localization of high Znanoparticles in low Z tissue matrices is presented here by using the STEM-in-SEM coupled toEDX analysis as a powerful technique. In addition we have optimized the measurements withthe goal of working with thicker slices. The work with thick samples also avoid the NPsdisplacement during cutting and increase the possibility of finding NPs when working with lowNPs doses (environmental relevant concentrations).For the optimization of measurements conditions, the resolution in our SEM-FEG has beenestimated using Fast Fourier Transform (FFT) algorithms on specific images of our tissue slices.We have used the SMART macro running inside the “SCION Image” program under windows [4,5]. Working at magnifications over 100 kx, for slices thicknesses of 200-300 nm and operatingvoltages of 20-30 kV, leads to resolutions below 10 nm (an adequate value for analyzing AuNPsof 23 nm average diameter).Figure 1 shows a representative image of AuNPs accumulated into the gill tissues after “invitro” exposures. From the obtained images it was possible to localize AuNPs (see also Figure2) associated with vesicles (it can be a large phagosome or also exocytosis). Nanoparticleswere also found in residual bodies (exocytosis).In summary this communications presents new results for “in vitro” fast testing andSTEM-in-SEM imaging of engineered AuNPs in a tissular ecotoxicity model. The authors gratefully acknowledge financial support from the Junta de Andalucia and EU FEDER (project PE2009-FQM-4554 and TEP-217) and the EU FP7AL-NANOFUNC project (CT-REGPOT2011-1-285895). |
| Databáze: | OpenAIRE |
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