title: Attenuation of endothelial-dependent vasodilator responses, induced by dye-encapsulated silica nanoparticles, in aortic vessels.
abstract: OBJECTIVE
  To determine the influence of silica nanoparticle (SiNP) number, size and dye encapsulation on conduit arterial function, in vitro.
  
  
  METHODS
  Rhodamine B isothiocyanate (RBITC) dye molecules were encapsulated in a silica shell to produce nanoparticles (silica RBITC nanoparticles) smaller than 100 nm size. Their effects on endothelial-dependent (acetylcholine; 0.01-200 µM) and -independent (sodium nitroprusside; 0.001-10 µM) dilator responses were examined.
  
  
  RESULTS
  When incubated with 1.96 × 10(12) nanoparticles/ml, both 30 and 70 nm SiNPs and silica RBITC nanoparticles significantly reduced endothelium-dependent, but not -independent, vasodilation. The degree of attenuation was related to nanoparticle surface area, rather than size, and influenced by dye encapsulation. Furthermore, attenuated dilation due to silica RBITC nanoparticles, but not SiNPs, could be partially restored using superoxide dismutase.
  
  
  CONCLUSIONS
  Our results suggest that the mechanism of attenuated dilation is different for SiNPs and silica RBITC nanoparticles, which has implications for the future fabrication of biocompatible nanoparticles for imaging diagnostics.
authors: School of Science & the Environment, Faculty of Science & Engineering, Manchester Metropolitan University, Manchester, M1 5GD, UK.
authors: Asima
authors: A
authors: Farooq
authors: Debra
authors: D
authors: Whitehead
authors: May
authors: M
authors: Azzawi
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects; D004396:Coloring Agents / Q000008:administration & dosage / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects; D008297:Male; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D012235:Rhodamines / Q000008:administration & dosage* / Q000494:pharmacology*; D012822:Silicon Dioxide / Q000737:chemistry*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000494:pharmacology*
chemical_list: D004396:Coloring Agents; D012235:Rhodamines; D014665:Vasodilator Agents; D012822:Silicon Dioxide; C027755:rhodamine isothiocyanate