title: Clinically applicable labeling of mammalian and stem cells by combining superparamagnetic iron oxides and transfection agents.
abstract: OBJECTIVE
  To label mammalian and stem cells by combining commercially available transfection agents (TAs) with superparamagnetic iron oxide (SPIO) magnetic resonance (MR) imaging contrast agents.
  
  
  METHODS
  Three TAs were incubated with ferumoxides and MION-46L in cell culture medium at various concentrations. Human mesenchymal stem cells, mouse lymphocytes, rat oligodendrocyte progenitor CG-4 cells, and human cervical carcinoma cells were incubated 2-48 hours with 25 microg of iron per milliliter of combined TAs and SPIO. Cellular labeling was evaluated with T2 relaxometry, MR imaging of labeled cell suspensions, and Prussian blue staining for iron assessment. Proliferation and viability of mesenchymal stem cells and human cervical carcinoma cells labeled with a combination of TAs and ferumoxides were evaluated.
  
  
  RESULTS
  When ferumoxides-TA or MION-46L-TA was used, intracytoplasmic particles stained with Prussian blue stain were detected for all cell lines with a labeling efficiency of nearly 100%. Limited or no uptake was observed for cells incubated with ferumoxides or MION-46L alone. For TA-SPIO-labeled cells, MR images and relaxometry findings showed a 50%-90% decrease in signal intensity and a more than 40-fold increase in T2s. Cell viability varied from 103.7% +/- 9 to 123.0% +/- 9 compared with control cell viability at 9 days, and cell proliferation was not affected by endosomal incorporation of SPIO nanoparticles. Iron concentrations varied with ferumoxides-TA combinations and cells with a maximum of 30.1 pg +/- 3.7 of iron per cell for labeled mesenchymal stem cells.
  
  
  CONCLUSIONS
  Magnetic labeling of mammalian cells with use of ferumoxides and TAs is possible and may enable cellular MR imaging and tracking in experimental and clinical settings.
authors.affiliation: Laboratory of Diagnostic Radiology Research, Clinical Center, National Institutes of Health, Bldg 10, Rm B1N256, 10 Center Dr, MSC 1074, Bethesda, MD 20892-1074, USA. jafrank@helix.nih.gov
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Frank
authors.forename: Brad R
authors.initials: BR
authors.lastname: Miller
authors.forename: Ali S
authors.initials: AS
authors.lastname: Arbab
authors.forename: Holly A
authors.initials: HA
authors.lastname: Zywicke
authors.forename: E Kay
authors.initials: EK
authors.lastname: Jordan
authors.forename: Bobbi K
authors.initials: BK
authors.lastname: Lewis
authors.forename: L Henry
authors.initials: LH
authors.lastname: Bryant
authors.forename: Jeff W M
authors.initials: JW
authors.lastname: Bulte
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007202:Indicators and Reagents / Q000493:pharmacokinetics*; D007501:Iron / Q000493:pharmacokinetics*; D008055:Lipids / Q000493:pharmacokinetics*; D008081:Liposomes; D008279:Magnetic Resonance Imaging; D051379:Mice; D010087:Oxides / Q000493:pharmacokinetics*; D011107:Polylysine / Q000493:pharmacokinetics*; D051381:Rats; D013234:Stem Cells / Q000378:metabolism; D014162:Transfection / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: D007202:Indicators and Reagents; D008055:Lipids; C086724:Lipofectamine; D008081:Liposomes; D010087:Oxides; D011107:Polylysine; D007501:Iron; D052203:Ferrosoferric Oxide