title: Multifunctional magnetic nanocarriers for image-tagged SiRNA delivery to intact pancreatic islets.
abstract: BACKGROUND
  With the ultimate hope of finding a cure for diabetes, researches are looking into altering the genetic profile of the beta cell as a way to manage metabolic dysregulation. One of the most powerful new approaches for the directed regulation of gene expression uses the phenomenon of RNA interference.
  
  
  METHODS
  Here, we establish the feasibility of a novel technology centered around multifunctional magnetic nanocarriers, which concurrently deliver siRNA to intact pancreatic islets and can be detected by magnetic resonance and optical imaging.
  
  
  RESULTS
  In the proof-of-principle studies described here, we demonstrate that, after in vitro incubation, magnetic nanoparticles carrying siRNA designed to target the model gene for enhanced green fluorescent protein are efficiently taken up by murine pancreatic islets, derived from egfp transgenic animals. This uptake can be visualized by magnetic resonance imaging and near-infrared fluorescence optical imaging and results in suppression of the target gene.
  
  
  CONCLUSIONS
  These results illustrate the value of our approach in overcoming the challenges associated with genetic modification of intact pancreatic islets in a clinically acceptable manner. Furthermore, an added advantage of our technology derives from the combined capability of our magnetic nanoparticles for siRNA delivery and magnetic labeling of pancreatic islets.
authors.affiliation: Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Zdravka
authors.initials: Z
authors.lastname: Medarova
authors.forename: Mohanraja
authors.initials: M
authors.lastname: Kumar
authors.forename: Shu-Wing
authors.initials: SW
authors.lastname: Ng
authors.forename: Junzheng
authors.initials: J
authors.lastname: Yang
authors.forename: Natasha
authors.initials: N
authors.lastname: Barteneva
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Evgenov
authors.forename: Victoria
authors.initials: V
authors.lastname: Petkova
authors.forename: Anna
authors.initials: A
authors.lastname: Moore
mesh_terms: D000818:Animals; D003920:Diabetes Mellitus / Q000628:therapy; D016503:Drug Delivery Systems / Q000379:methods*; D005290:Ferric Compounds; D005786:Gene Expression Regulation; D015316:Genetic Therapy / Q000379:methods; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology*; D016381:Islets of Langerhans Transplantation; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D053758:Nanoparticles / Q000008:administration & dosage*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D015203:Reproducibility of Results
chemical_list: D005290:Ferric Compounds; D034741:RNA, Small Interfering; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C000499:ferric oxide