title: Near infrared imaging and photothermal ablation of vascular inflammation using single-walled carbon nanotubes.
abstract: BACKGROUND
  Macrophages are critical contributors to atherosclerosis. Single-walled carbon nanotubes (SWNTs) show promising properties for cellular imaging and thermal therapy, which may have application to vascular macrophages.
  
  
  RESULTS
  In vitro uptake and photothermal destruction of mouse macrophage cells (RAW264.7) were performed with SWNTs (14.7 nmol/L) exposed to an 808-nm light source. SWNTs were taken up by 94 ± 6% of macrophages, and light exposure induced 93 ± 3% cell death. In vivo vascular macrophage uptake and ablation were then investigated in carotid-ligated FVB mice (n=33) after induction of hyperlipidemia and diabetes. Two weeks postligation, near-infrared fluorescence (NIRF) carotid imaging (n=12) was performed with SWNT-Cy5.5 (8 nmol of Cy5.5) given via the tail vein. Photothermal heating and macrophage apoptosis were evaluated on freshly excised carotid arteries (n=21). NIRF of SWNTs showed higher signal intensity in ligated carotids compared with sham, confirmed by both in situ and ex vivo NIRF imaging (P<0.05, ligation versus sham). Immunofluorescence staining showed colocalization of SWNT-Cy5.5 and macrophages in atherosclerotic lesions. Light (808 nm) exposure of freshly excised carotids showed heating and induction of macrophage apoptosis in ligated left carotid arteries with SWNTs, but not in control groups without SWNTs or without light exposure.
  
  
  CONCLUSIONS
  Carbon nanotubes accumulate in atherosclerotic macrophages in vivo and provide a multifunctional platform for imaging and photothermal therapy of vascular inflammation.
authors: Division of Cardiovascular Medicine, Stanford University, Stanford, CA, USA. hkosuge@stanford.edu
authors: Hisanori
authors: H
authors: Kosuge
authors: Sarah P
authors: SP
authors: Sherlock
authors: Toshiro
authors: T
authors: Kitagawa
authors: Rajesh
authors: R
authors: Dash
authors: Joshua T
authors: JT
authors: Robinson
authors: Hongjie
authors: H
authors: Dai
authors: Michael V
authors: MV
authors: McConnell
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy*; D002478:Cells, Cultured; D003952:Diagnostic Imaging / Q000379:methods; D007249:Inflammation / Q000175:diagnosis; D007259:Infrared Rays; D053685:Laser Therapy; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D037742:Nanotubes, Carbon; D061848:Optical Imaging
chemical_list: D037742:Nanotubes, Carbon
keywords: atherosclerosis; imaging; inflammation; macrophage; photothermal therapy