title: Tripod USPIONs with high aspect ratio show enhanced T2 relaxation and cytocompatibility.
abstract: OBJECTIVE
  We synthesized ultra-small iron oxide nanoparticles (USPIONs) with tripod morphology and studied the effect of the aspect ratio (AR) of the tripod arms on mass magnetization, T2 relaxation and cytocompatibility in human cell lines.
  
  
  METHODS
  Tripods were prepared by controlling the temperature during the thermal decomposition of Fe(CO)5, and their magnetic properties were characterized by superconducting quantum interference device, and NMR. Citric acid stabilized USPIONs were used to assess cytocompatibility.
  
  
  RESULTS
  T2 relaxivity of tripods showed dependency on AR of the tripod arm. Liver enzyme levels in presence of tripods were comparable to spherical USPIONs, and surprisingly tripods induced lower levels of reactive oxygen species.
  
  
  CONCLUSIONS
  Tripod USPIONs with high AR arms possess excellent magnetic properties and cytocompatibility for further exploration as MRI contrast agents.
authors.affiliation: Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany.
authors.forename: Pradeep P
authors.initials: PP
authors.lastname: Wyss
authors.affiliation: Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany.|BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Surya
authors.initials: S
authors.lastname: Lamichhane
authors.affiliation: Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany.|Institute for Life Science, University of Applied Sciences Northwestern Switzerland, Gründenstrasse 40, 4132 Muttenz, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Rauber
authors.affiliation: Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Thomann
authors.affiliation: Department of Chemistry & Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Karl W
authors.initials: KW
authors.lastname: Krämer
authors.affiliation: Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany.|BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: V Prasad
authors.initials: VP
authors.lastname: Shastri
mesh_terms: D002460:Cell Line / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry* / Q000627:therapeutic use; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry* / Q000627:therapeutic use; D005290:Ferric Compounds / Q000737:chemistry / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000627:therapeutic use; D010316:Particle Size
chemical_list: D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide
keywords: ROS induction; SQUID magnetometry; contrast agent; hepatocompatibility; nanomaterial shape