title: Near infrared dye indocyanine green doped silica nanoparticles for biological imaging.
abstract: Indocyanine green (ICG) is an FDA-approved near infrared (NIR) fluorescent dye used in clinical imaging. However, its applications remain limited due to its short half-life, nonspecific plasma binding, optical instability, and poor aqueous stability. Dye doped silica nanoparticles provide an effective barrier in keeping the dye away from the surrounding environment, but ICG cannot be encapsulated into silica easily by conventional methods. In this study, ICG molecules ion-paired with a cationic polymer polyethylenimine (PEI) were successfully encapsulated into a silica matrix to form ICG doped silica nanoparticles by using the Stöber method. Pairing with PEI reduced self-quenching of fluorescence by preventing the aggregation of ICG molecules in silica nanoparticles. Dye leakage was also reduced to the level of 3-6% loss in 5 days. NIR fluorescence images of ICG doped silica NPs below a 2.0 cm thick porcine muscle sample illuminated by NIR light were obtained.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-747, South Korea.
authors.forename: Bo
authors.initials: B
authors.lastname: Quan
authors.forename: Kihwan
authors.initials: K
authors.lastname: Choi
authors.forename: Young-Hwa
authors.initials: YH
authors.lastname: Kim
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.forename: Doo Soo
authors.initials: DS
authors.lastname: Chung
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005456:Fluorescent Dyes / Q000737:chemistry*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007208:Indocyanine Green / Q000737:chemistry*; D007259:Infrared Rays; D057054:Molecular Imaging / Q000379:methods*; D009132:Muscles / Q000166:cytology; D053758:Nanoparticles; D011094:Polyethyleneimine / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry* / Q000633:toxicity; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D012822:Silicon Dioxide; D011094:Polyethyleneimine; D007208:Indocyanine Green