title: Macrophage scavenger receptor A mediates the uptake of gold colloids by macrophages in vitro.
abstract: OBJECTIVE
  While numerous studies have reported on nanoparticle uptake by phagocytic cells, the mechanisms of this uptake are poorly understood. A metastudy of research focusing on biological particulate matter has postulated that nanoparticles cannot be phagocytosed and therefore must enter cells via pinocytosis. The purpose of this study was to identify the route(s) of uptake of gold nanoparticles in vitro and to determine if these route(s) depend on particle size.
  
  
  METHODS
  The parent RAW264.7 cell line and its derivatives, transduced with a virus carrying siRNA to macrophage scavenger receptor A, were used as model phagocytes. Citrate-stabilized gold colloids were used as model nanoparticles. We used chemical inhibitors known to interfere with specific routes of particulate uptake. We developed multifocal light microscopy methods including multifocal stack analysis with NIH ImageJ software to analyze cell uptake.
  
  
  RESULTS
  Irrespective of size, gold nanoparticles are internalized by macrophages via multiple routes, including both phagocytosis and pinocytosis. If either route was blocked, the particles entered cells via the other route.
  
  
  CONCLUSIONS
  Gold nanoparticles with hydrodynamic sizes below 100 nm can be phagocytosed. Phagocytosis of anionic gold colloids by RAW264.7 cells is mediated by macrophage scavenger receptor A.
authors.affiliation: Immunology, Biomedical Research Center (CINBIO), Universidad de Vigo, Campus Lagoas Marcosende, 36310 Vigo, Pontevedra. Spain.
authors.forename: Angela
authors.initials: A
authors.lastname: França
authors.forename: Parag
authors.initials: P
authors.lastname: Aggarwal
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Barsov
authors.forename: Serguei V
authors.initials: SV
authors.lastname: Kozlov
authors.forename: Marina A
authors.initials: MA
authors.lastname: Dobrovolskaia
authors.forename: África
authors.initials: Á
authors.lastname: González-Fernández
mesh_terms: D000818:Animals; D002460:Cell Line; D017979:Gold Colloid / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D010587:Phagocytosis; D010873:Pinocytosis; D051116:Receptors, Scavenger / Q000378:metabolism*; D051117:Scavenger Receptors, Class A / Q000378:metabolism*
chemical_list: D017979:Gold Colloid; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A