title: Quantification of nanoparticle uptake by cells using an unbiased sampling method and electron microscopy.
abstract: OBJECTIVE
  By randomly sampling a known fraction of a pellet of cultured cells, we have accurately estimated the mean number of 50 nm gold nanoparticles accumulated within a single cell. Cellular nanoparticle uptake was measured using a combination of stereological sampling techniques and transmission electron microscopy.
  
  
  METHODS
  Nanoparticles were counted individually and their intracellular location was recorded. Quantifying cell and nanoparticle number by analyzing a known fraction of the sample led to precise estimates of intracellular nanoparticle numbers and their spatial locations on an ultrastructural level. We propose a simple and reliable fractionator design and show its applicability and potential using fibroblast cells exposed to 50-nm gold nanoparticles.
  
  
  CONCLUSIONS
  We demonstrate that this approach is suitable for any electron-dense nanomaterial resolvable by electron microscopy and any convex-shaped cells. In addition, the fractionator concept is flexible enough to be used for spatio-temporal or in vivo studies.
authors.affiliation: Nano Systems Biology Group, Center for Molecular Biosciences, University of Ulster, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Elsaesser
authors.forename: Clifford A
authors.initials: CA
authors.lastname: Barnes
authors.forename: George
authors.initials: G
authors.lastname: McKerr
authors.forename: Anna
authors.initials: A
authors.lastname: Salvati
authors.forename: Iseult
authors.initials: I
authors.lastname: Lynch
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Dawson
authors.forename: C Vyvyan
authors.initials: CV
authors.lastname: Howard
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002463:Cell Membrane Permeability; D004867:Equipment Design; D005347:Fibroblasts / Q000166:cytology*; D051379:Mice; D046529:Microscopy, Electron, Transmission / Q000295:instrumentation* / Q000379:methods; D053758:Nanoparticles / Q000032:analysis* / Q000648:ultrastructure