title: Force dependent internalization of magnetic nanoparticles results in highly loaded endothelial cells for use as potential therapy delivery vectors.
abstract: OBJECTIVE
  To investigate the kinetics, mechanism and extent of MNP loading into endothelial cells and the effect of this loading on cell function.
  
  
  METHODS
  MNP uptake was examined under field on/off conditions, utilizing varying magnetite concentration MNPs. MNP-loaded cell viability and functional integrity was assessed using metabolic respiration, cell proliferation and migration assays.
  
  
  RESULTS
  MNP uptake in endothelial cells significantly increased under the influence of a magnetic field versus non-magnetic conditions. Larger magnetite density of the MNPs led to a higher MNP internalization by cells under application of a magnetic field without compromising cellular respiration activity. Two-dimensional migration assays at no field showed that higher magnetite loading resulted in greater cell migration rates. In a three-dimensional migration assay under magnetic field, the migration rate of MNP-loaded cells was more than twice that of unloaded cells and was comparable to migration stimulated by a serum gradient.
  
  
  CONCLUSIONS
  Our results suggest that endothelial cell uptake of MNPs is a force dependent process. The in vitro assays determined that cell health is not adversely affected by high MNP loadings, allowing these highly magnetically responsive cells to be potentially beneficial therapy (gene, drug or cell) delivery systems.
authors.affiliation: School of Biomedical Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Cristin
authors.initials: C
authors.lastname: MacDonald
authors.forename: Kenneth
authors.initials: K
authors.lastname: Barbee
authors.forename: Boris
authors.initials: B
authors.lastname: Polyak
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008280:Magnetics; D053758:Nanoparticles
chemical_list: D052203:Ferrosoferric Oxide