title: Cetuximab-labeled liposomes containing near-infrared probe for in vivo imaging.
abstract: A new liposome-based near-infrared probe that combines both imaging and targeting abilities was developed for application in medical imaging. The near-infrared fluorescent molecule indocyanine green (ICG), and the cetuximab monoclonal antibody for epidermal growth factor receptor (EGFR) were attached to liposomes by passive adsorption. It was found that ICG molecules adsorbed to the liposomes are more fluorescent than free ICG and have a larger quantum yield. Cetuximab-adsorbed fluorescent liposomes preserved EGFR recognition, as is evident from internalization and selective binding to A431 colon carcinoma cells overexpressing EGFR. The binding of cetuximab-targeted fluorescent liposomes to A431 compared with IEC-6 cells (normal enterocytes expressing physiological EGFR levels) was greater by a factor of 3.5, ensuring imaging abilities with available fluorescent equipment. Due to relatively high quantum yield and specific tumor cell-recognizing ability, this technology deserves further in vivo evaluation for imaging and diagnostic purposes.
  
  
  BACKGROUND
  A new liposome-based near-infrared probe combining both imaging and targeting abilities is reported. Due to relatively high quantum yield and EGFR-expressing tumor cell specificity, this technology deserves further in vivo evaluation for imaging and diagnostic purposes.
authors.affiliation: Casali Institute of Applied Chemistry, Institute of Chemistry and Center for Nanoscience and Nanotechnology, Jerusalem, Israel.
authors.forename: Emma
authors.initials: E
authors.lastname: Portnoy
authors.forename: Shimon
authors.initials: S
authors.lastname: Lecht
authors.forename: Philip
authors.initials: P
authors.lastname: Lazarovici
authors.forename: Dganit
authors.initials: D
authors.lastname: Danino
authors.forename: Shlomo
authors.initials: S
authors.lastname: Magdassi
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry*; D061067:Antibodies, Monoclonal, Humanized; D045744:Cell Line, Tumor; D000068818:Cetuximab; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D020285:Cryoelectron Microscopy; D003952:Diagnostic Imaging / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D007208:Indocyanine Green / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D008081:Liposomes; D066246:ErbB Receptors; D007208:Indocyanine Green; D000068818:Cetuximab