title: Electron microscopy localization and characterization of functionalized composite organic-inorganic SERS nanoparticles on leukemia cells.
abstract: We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic nanoparticle (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet scanning electron microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron (BSE) detector was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution transmission electron microscopy (TEM) images and scanning Auger electron spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens.
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Durand Building Room 139, 496 Lomita Mall, Stanford, CA 94305, USA. alkoh@stanford.edu
authors.forename: Ai Leen
authors.initials: AL
authors.lastname: Koh
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Shachaf
authors.forename: Sailaja
authors.initials: S
authors.lastname: Elchuri
authors.forename: Garry P
authors.initials: GP
authors.lastname: Nolan
authors.forename: Robert
authors.initials: R
authors.lastname: Sinclair
mesh_terms: D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry / Q000648:ultrastructure; D018799:Intercellular Adhesion Molecule-1 / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods; D020298:U937 Cells / Q000648:ultrastructure*
chemical_list: D018796:Immunoconjugates; D018799:Intercellular Adhesion Molecule-1; D012834:Silver