Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
nanoSIMS: a new analytical tool for ultra-fine feature analysis using secondary ion emission R. Stern* and Peta Clode The University of Western Australia Centre for Microscopy and Microanalysis [email protected] NanoSIMS 50 The Centre for Microscopy & Microanalysis NanoSIMS 50 The Centre for Microscopy & Microanalysis nanoSIMS labs #10 NanoSIMS 50 The Centre for Microscopy & Microanalysis SIMS Secondary Ion Mass Spectrometry probing analytical technique for measuring the surface or near surface chemical or isotopic composition of solids uses probe ions to sputter target ions in laterally microscale or smaller regions (ion microprobe) analytical characteristics: nm depth resolution lateral resolution 10’s nm to mm most sensitive of the probing analytical techniques, ppb-ppm entire periodic table, H to U simple sample preparation NanoSIMS 50 The Centre for Microscopy & Microanalysis SIMS Data cps,ppm Se Basic from tiny mass consumed 18 O/ 16O 24Mg/28Si Mass spectrum ratios Dimensions: 1 dimension 2 dimensions ‘image’ (map) of the surface distribution of secondary ion species 3 dimensions NanoSIMS 50 ‘depth profile’: composition along a line Depth profile normal to the surface ‘line scan’: composition along a line Line scan parallel to the surface Image a stacked series of secondary ion images collected at discrete depths into the target The Centre for Microscopy & Microanalysis SIMS analytical Energy Analyzer Mass Analyzer Ion source Secondary ion Collection Optics Primary ion column Detector Sample under vacuum NanoSIMS 50 The Centre for Microscopy & Microanalysis High mass resolution analyzer Detector array: 5 isotopes acquired simultaneously Ion sources: O-, Cs+ Normal, co-axial primary & secondary ions samples Sample introduction NanoSIMS 50 The Centre for Microscopy & Microanalysis Features of NanoSIMS dynamic SIMS for bulk sample ion chemical/isotopic characterization not for molecular identification or oxidation state probe lateral resolution 50 nm for 133Cs+ 200 nm for 16O- ability to scan the primary beam and record secondary ion images at ultrafine-scale lateral resolution very low eroson rate, ~nm/hr (sample preservation) simultaneous multicollection of up to 5 isotope species routine high mass resolution resolve isobaric interferences NanoSIMS 50 The Centre for Microscopy & Microanalysis Ion imaging of TiCN alloy demonstrating sub-50 nm edge resolution with Cs+ 10 x 10 um, 24C2 3 x 3 um, 26CN NanoSIMS 50 The Centre for Microscopy & Microanalysis Engineered Materials Minerals Semiconductors Ceramics Alloys Extraterrestrial dust Geochronology Ore minerals BIOMATERIALS sub-cellular imaging biochemical function cancer research pharmaceuticals NanoSIMS 50 The Centre for Microscopy & Microanalysis NanoSIMS labs 0. Harvard Medical School/ MIT, Boston USA National Resource for Mass Spectrometry Imaging, NIH NCRR bio-SIMS program 1. Washington University, Saint Louis, MO 2. Max Planck Institute, Mainz, Germany bio-SIMS program 3. Institut Curie, Paris, France 4. Oxford University, U.K 5. Lawrence Livermore National Lab, Livermore, CA, USA University of California, Davis 6. National Institute for Materials Science, Tsukuba, Japan bio-SIMS program 7. LAM, Centre de Recherche Public-GL, Luxembourg 8. ExxonMobil, New Jersey, USA 9. University of Tokyo 10. The UWA bio-SIMS program 11. Rouen Univ, France NanoSIMS 50 The Centre for Microscopy & Microanalysis Non-metallic elements used in SIMS biological analysis Naturally-occurring isotopes Artificial isotopes (stable or radioactive) 12C 14C 14N – all cell organelles – DNA, RNA, proteins 31P – DNA, RNA (nucleic acids) 32S – proteins – turnover/pathways of C 15N – turnover/pathways of labelled amino acids (proteins), nucleic acids 17F – Fluoracil, cancer drug targetting chromosomes 81Br – in Bromodeoxyuridine (BrdU), specifically incorporated into DNA during DNA synthesis 123, 125, 127I – in Iododeoxyuridine NanoSIMS 50 The Centre for Microscopy & Microanalysis Examples of metallic elements used in SIMS biological analysis Li, Na, K, Rb, Cs Be, Mg, Ca, Sr, Ba Ti, Cr, Mn, Fe, Ni, Pb, Al, In Au, Ag Sc, lanthanides, actinides to date, few studies, poor sensitivity and spatial resolution NanoSIMS 50 The Centre for Microscopy & Microanalysis O- primary ion bombardment, positive secondary ions, and a silicon matrix NanoSIMS 50 The Centre for Microscopy & Microanalysis Cs+ primary ion bombardment, negative secondary ions, and a silicon matrix NanoSIMS 50 The Centre for Microscopy & Microanalysis Sample preparation must be dehydrated, +/- fast freezing, chemical fixation (glutaraldehyde, Os tetroxide), epoxy embedding, cryo-sectioning (0.3 – 1 µm) will feature of interest be preserved? other documentation techniques to map features (confocal, VPSEM, TEM, etc.) Example of human hair cross-section deposited on Si (Hallegot and Corcuff, 1993) Scanning electron microscopy images cortex cuticle NanoSIMS 50 The Centre for Microscopy & Microanalysis nanoSIMS samples Sample holder for 1 cm samples Thin membranes on Si wafer NanoSIMS 50 The Centre for Microscopy & Microanalysis Imaging of resin embedded biological tissues 12C14N 32S A mucous-producing 150 mm cell in coral tissue Scale = 3um Primary ions: Cs+ 12C14N 31P A symbiotic algae in coral tissue Scale = 2um Primary ions: Cs+ NanoSIMS 50 The Centre for Microscopy & Microanalysis Imaging isotopic tracers in resin embedded biological tissues 44Ca / 40Ca 44Ca used as a tracer of calcium (40Ca) to determine pathways of movement & uptake 1. 4. 3. Coral epithelium 44Ca 1 min Scale = 5um FOV = 35um Primary ions: O- 150 mm 2. Significant 44Ca uptake Region 44Ca/40Ca Natural abundance 0.02 1. Mucous cell 0.05 2. Spiked Seawater 0.7 3. Epithelial cells 0.37 4. Stinging cell 0.02 NanoSIMS 50 The Centre for Microscopy & Microanalysis Mouse cochlea cells NanoSIMS 50 The Centre for Microscopy & Microanalysis Imaging of As within human hair Audinot et al. (2003) Heavy metal exposure NanoSIMS 50 The Centre for Microscopy & Microanalysis Analytical Issues: will the metal ions be detectable? are there non-metallic ion labels that can be used as proxies for the metals? quantitation: how important? sample preparation to avoid element migration or loss NanoSIMS 50 The Centre for Microscopy & Microanalysis nanoSIMS & ARC Metals in Medicine is capable of playing a vital role the analytical capabilities and experience with metals in biological media needs to be developed R. Stern and P. Clode are here to enter into research partnerships with you NanoSIMS 50 The Centre for Microscopy & Microanalysis