title: Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping.
abstract: The use of near-infrared or infrared photons is a promising approach for biomedical imaging in living tissue. This technology often requires exogenous contrast agents with combinations of hydrodynamic diameter, absorption, quantum yield and stability that are not possible with conventional organic fluorophores. Here we show that the fluorescence emission of type II quantum dots can be tuned into the near infrared while preserving absorption cross-section, and that a polydentate phosphine coating renders them soluble, disperse and stable in serum. We then demonstrate that these quantum dots allow a major cancer surgery, sentinel lymph node mapping, to be performed in large animals under complete image guidance. Injection of only 400 pmol of near-infrared quantum dots permits sentinel lymph nodes 1 cm deep to be imaged easily in real time using excitation fluence rates of only 5 mW/cm(2). Taken together, the chemical, optical and in vivo data presented in this study demonstrate the potential of near-infrared quantum dots for biomedical imaging.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Sungjee
authors.initials: S
authors.lastname: Kim
authors.forename: Yong Taik
authors.initials: YT
authors.lastname: Lim
authors.forename: Edward G
authors.initials: EG
authors.lastname: Soltesz
authors.forename: Alec M
authors.initials: AM
authors.lastname: De Grand
authors.forename: Jaihyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Akira
authors.initials: A
authors.lastname: Nakayama
authors.forename: J Anthony
authors.initials: JA
authors.lastname: Parker
authors.forename: Tomislav
authors.initials: T
authors.lastname: Mihaljevic
authors.forename: Rita G
authors.initials: RG
authors.lastname: Laurence
authors.forename: Delphine M
authors.initials: DM
authors.lastname: Dor
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Cohn
authors.forename: Moungi G
authors.initials: MG
authors.lastname: Bawendi
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D009369:Neoplasms / Q000601:surgery*; D010720:Phosphines / Q000737:chemistry; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D019265:Spectroscopy, Near-Infrared; D013552:Swine; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D010720:Phosphines; C044646:phosphine