title: Application of low-energy scanning transmission electron microscopy for the study of Pt-nanoparticle uptake in human colon carcinoma cells.
abstract: High-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) in a scanning electron microscope facilitates the acquisition of images with high chemical sensitivity and high resolution. HAADF STEM at low electron energies is particularly suited to image nanoparticles (NPs) in thin cell sections which are not subjected to poststaining procedures as demonstrated by comparison with bright-field TEM. High membrane contrast is achieved and distinction of NPs with different chemical composition is possible at first sight. Low-energy HAADF STEM was applied to systematically study the uptake of Pt-NPs with a broad size distribution in HT29 colon carcinoma cells as a function of incubation time and incubation temperature. The cellular dose was quantified, that is, the amount and number density of NPs taken up by the cells, as well as the particle-size distribution. The results show a strong dependence of the amount of incubated NPs on the exposure time which can be understood by considering size-dependent diffusion and gravitational settling of the NPs in the cell culture medium.
authors.affiliation: Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie (KIT) , 76128 Karlsruhe , Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Blank
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schneider
authors.forename: Dagmar
authors.initials: D
authors.lastname: Gerthsen
authors.forename: Helge
authors.initials: H
authors.lastname: Gehrke
authors.forename: Katharina
authors.initials: K
authors.lastname: Jarolim
authors.forename: Doris
authors.initials: D
authors.lastname: Marko
mesh_terms: D003110:Colonic Neoplasms / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*; D010316:Particle Size; D010984:Platinum / Q000737:chemistry* / Q000493:pharmacokinetics*
chemical_list: D010984:Platinum