title: Trafficking of a dual-modality magnetic resonance and fluorescence imaging superparamagnetic iron oxide-based nanoprobe to lymph nodes.
abstract: OBJECTIVE
  This study aims to develop and characterize the trafficking of a dual-modal agent that identifies primary draining or sentinel lymph node (LN).
  
  
  METHODS
  Herein, a dual-reporting silica-coated iron oxide nanoparticle (SCION) is developed. Nude mice were imaged by magnetic resonance (MR) and optical imaging and axillary LNs were harvested for histological analysis. Trafficking through lymphatics was observed with intravital and ex vivo confocal microscopy of popliteal LNs in B6-albino, CD11c-EYFP, and lys-EGFP transgenic mice.
  
  
  RESULTS
  In vivo, SCION allows visualization of LNs. The particle's size and surface functionality play a role in its passive migration from the intradermal injection site and its minimal uptake by CD11c+ dendritic cells and CD169+ and lys+ macrophages.
  
  
  CONCLUSIONS
  After injection, SCION passively migrates to LNs without macrophage uptake and then can be used to image LN(s) by MRI and fluorescence. Thus, SCION can potentially be developed for use in sentinel node resections or for intralymphatic drug delivery.
authors.affiliation: Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Ambika
authors.initials: A
authors.lastname: Bumb
authors.forename: Celeste A S
authors.initials: CA
authors.lastname: Regino
authors.forename: Jackson G
authors.initials: JG
authors.lastname: Egen
authors.forename: Marcelino
authors.initials: M
authors.lastname: Bernardo
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Dobson
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Germain
authors.forename: Peter L
authors.initials: PL
authors.lastname: Choyke
authors.forename: Martin W
authors.initials: MW
authors.lastname: Brechbiel
mesh_terms: D000818:Animals; D003911:Dextrans / Q000378:metabolism*; D005453:Fluorescence; D008198:Lymph Nodes / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D051379:Mice; D008819:Mice, Nude; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013194:Staining and Labeling
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; D012822:Silicon Dioxide; C065507:ferumoxides