title: Intrinsically superparamagnetic Fe-hydroxyapatite nanoparticles positively influence osteoblast-like cell behaviour.
abstract: BACKGROUND
  Superparamagnetic nanoparticles (MNPs) have been progressively explored for their potential in biomedical applications and in particular as a contrast agent for diagnostic imaging, for magnetic drug delivery and more recently for tissue engineering applications. Considering the importance of having safe MNPs for such applications, and the essential role of iron in bone remodelling, this study developed and analysed novel biocompatible and bioreabsorbable superparamagnetic nanoparticles, that avoid the use of poorly tolerated magnetite based nanoparticles, for bone tissue engineering applications.
  
  
  RESULTS
  MNPs were obtained by doping hydroxyapatite (HA) with Fe ions, by directly substituting Fe2+ and Fe3+ into the HA structure yielding superparamagnetic bioactive phase. In the current study, we have investigated the effects of increasing concentrations (2000 μg/ml; 1000 μg/ml; 500 μg/ml; 200 μg/ml) of FeHA MNPs in vitro using Saos-2 human osteoblast-like cells cultured for 1, 3 and 7 days with and without the exposure to a static magnetic field of 320 mT. Results demonstrated not only a comparable osteoblast viability and morphology, but increased in cell proliferation, when compared to a commercially available Ha nanoparticles, even with the highest dose used. Furthermore, FeHA MNPs exposure to the static magnetic field resulted in a significant increase in cell proliferation throughout the experimental period, and higher osteoblast activity.In vivo preliminary results demonstrated good biocompatibility of FeHA superparamagnetic material four weeks after implantation into a critical size lesion of the rabbit condyle.
  
  
  CONCLUSIONS
  The results of the current study suggest that these novel FeHA MNPs may be particularly relevant for strategies of bone tissue regeneration and open new perspectives for the application of a static magnetic field in a clinical setting of bone replacement, either for diagnostic imaging or magnetic drug delivery.
authors: Laboratory of Biomechanics and Technology Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy. s.panseri@biomec.ior.it
authors: Silvia
authors: S
authors: Panseri
authors: Carla
authors: C
authors: Cunha
authors: Teresa
authors: T
authors: D'Alessandro
authors: Monica
authors: M
authors: Sandri
authors: Gianluca
authors: G
authors: Giavaresi
authors: Maurilio
authors: M
authors: Marcacci
authors: Clark T
authors: CT
authors: Hung
authors: Anna
authors: A
authors: Tampieri
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D017886:Durapatite / Q000493:pharmacokinetics*; D005290:Ferric Compounds / Q000493:pharmacokinetics*; D005296:Ferrous Compounds / Q000493:pharmacokinetics*; D006801:Humans; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D010865:Pilot Projects; D011817:Rabbits
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D017886:Durapatite; D000469:Alkaline Phosphatase