title: Serum-derived nanoparticles: de novo generation and growth in vitro, and internalization by mammalian cells in culture.
abstract: OBJECTIVE
  While nanoparticles (NPs) have been shown to form spontaneously in body fluids such as serum, the possible implications of these NPs for cell cultures that use supporting media containing serum remain unclear. To understand the de novo formation of NPs, we delineated their growth characteristics, chemical composition and interaction with cells in culture.
  
  
  METHODS
  Serum-derived particles were analyzed using a combination of dynamic light scattering, turbidity measurements, spectroscopic techniques and optical/electron microscopies.
  
  
  RESULTS
  NPs were found in serum and in serum-containing medium and they increased in size and number during incubation. The mineral particles, consisting mainly of calcium carbonate phosphate bound to organics such as proteins, underwent an amorphous-to-crystalline transformation with time. Serum-derived particles were internalized by the cells tested, eventually reaching lysosomal compartments.
  
  
  CONCLUSIONS
  The spontaneous formation of serum-derived NPs and their internalization by cells may have overlooked effects on cultured cells in vitro as well as potential pathophysiological consequences in vivo.
authors.affiliation: Laboratory of Nanomaterials, Chang Gung University, Gueishan, Taoyuan 333, Taiwan.
authors.forename: Hsin-Hsin
authors.initials: HH
authors.lastname: Peng
authors.forename: Jan
authors.initials: J
authors.lastname: Martel
authors.forename: Yu-Hsiu
authors.initials: YH
authors.lastname: Lee
authors.forename: David M
authors.initials: DM
authors.lastname: Ojcius
authors.forename: John D
authors.initials: JD
authors.lastname: Young
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry; D002460:Cell Line; D051379:Mice; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D002119:Calcium Carbonate