title: Soft X-ray spectromicroscopy for speciation, quantitation and nano-eco-toxicology of nanomaterials.
abstract: There is a critical need for methods that provide simultaneous detection, identification, quantitation and visualization of nanomaterials at their interface with biological and environmental systems. The approach should allow speciation as well as elemental analysis. Using the intrinsic X-ray absorption properties, soft X-ray scanning transmission X-ray spectromicroscopy (STXM) allows characterization and imaging of a broad range of nanomaterials, including metals, oxides and organic materials, and at the same time is able to provide detailed mapping of biological components. Thus, STXM offers considerable potential for application to research on nanomaterials in biology and the environment. The potential and limitations of STXM in this context are discussed using a range of examples, focusing on the interaction of nanomaterials with microbial cells, biofilms and extracellular polymers. The studies outlined include speciation and mapping of metal-containing nanomaterials (Ti, Ni, Cu) and carbon-based nanomaterials (multiwalled carbon nanotubes, C60 fullerene). The benefits of X-ray fluorescence detection in soft X-ray STXM are illustrated with a study of low levels of Ni in a natural river biofilm.
authors.affiliation: Environment Canada, Saskatoon, SK, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Lawrence
authors.affiliation: Environment Canada, Saskatoon, SK, Canada.
authors.forename: G D W
authors.initials: GD
authors.lastname: Swerhone
authors.affiliation: Canadian Light Source Inc, University of Saskatchewan, SK, Canada.
authors.forename: J J
authors.initials: JJ
authors.lastname: Dynes
authors.affiliation: Food and Bioproducts Sciences, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Korber
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada.
authors.forename: A P
authors.initials: AP
authors.lastname: Hitchcock
mesh_terms: D018441:Biofilms; D017753:Ecosystem; D005453:Fluorescence; D053768:Metal Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure*; D008670:Metals; D008855:Microscopy, Electron, Scanning / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D049329:Nanostructures / Q000032:analysis / Q000633:toxicity* / Q000648:ultrastructure*; D037742:Nanotubes, Carbon; D011108:Polymers; D014965:X-Rays
chemical_list: D008670:Metals; D037742:Nanotubes, Carbon; D011108:Polymers
keywords: Bacteria; STXM; Scanning Transmission X-Ray Microscopy; biofilms; carbon nanotubes; metals; nanomaterials/nanoparticles