title: [First results with catheter and magnetically guided and detached polymerized ferromagnetic particle filaments and heat-induced particle release using the Stereotaxis Niobe system].
abstract: OBJECTIVE
  To develop a new technique for intravascular guidance and the release of magnetized ferromagnetic nanoparticles using a polymerized filament by means of an external magnetic field.
  
  
  METHODS
  Ferromagnetic nanoscaled beads were embedded in temperature-sensitive gels to form filaments after polymerization. Deflection of the filaments was assessed in a Stereotaxis Niobe magnetic navigation system (MNS) in comparison with dedicated guide wires. The curvature was measured as a surrogate parameter for deflection. In combination with commercially available catheters, the filaments were navigated in a perfused aneurysmatic vessel model and a perfused branched vessel model under the influence of two permanent magnets of the Niobe MNS. The magnetic field vector was varied in all three dimensions. After positioning, the magnetic colloid-containing filaments were exposed to an electromagnetic field of 45 kA/m, 200 kHz for a period of 5 minutes for non-invasive heating.
  
  
  RESULTS
  The filaments showed superior deflectability compared to the dedicated guide wires (p = 0.0091). The curvature was 0.54 +/- 0.12 mm(-1) for the filaments and 0.33 +/- 0.21 mm(-1) for the guide wires. In combination with angiography catheters, magnetic guidance and accumulation of specially designed filaments were possible in the perfused vessel model. Inductive heating allowed non-invasive disintegration and releasing of the nanoparticles in all filaments.
  
  
  CONCLUSIONS
  This feasibility study shows that magnetic guidance and targeting of a specially designed magnetic colloid-containing filament and subsequent disintegration are feasible. This technique offers the potential for controlled local drug release.
authors.affiliation: Helmholtz-Institut, RWTH Aachen. baumann@hia.rwth-aachen.de
authors.forename: M
authors.initials: M
authors.lastname: Baumann
authors.forename: A
authors.initials: A
authors.lastname: Mahnken
authors.forename: M
authors.initials: M
authors.lastname: Floren
authors.forename: R W
authors.initials: RW
authors.lastname: Günther
authors.forename: D
authors.initials: D
authors.lastname: Müller-Schulte
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rode
mesh_terms: D000783:Aneurysm / Q000601:surgery*; D005290:Ferric Compounds; D006801:Humans; D008280:Magnetics; D008953:Models, Anatomic; D049329:Nanostructures; D015642:Radiology, Interventional / Q000379:methods*; D012828:Silicones; D025321:Surgery, Computer-Assisted
chemical_list: D005290:Ferric Compounds; D012828:Silicones