title: Functional double-shelled silicon nanocrystals for two-photon fluorescence cell imaging: spectral evolution and tuning.
abstract: Functional near-IR (NIR) emitting nanoparticles (NPs) adapted for two-photon excitation fluorescence cell imaging were obtained starting from octadecyl-terminated silicon nanocrystals (ncSi-OD) of narrow photoluminescence (PL) spectra having no long emission tails, continuously tunable over the 700-1000 nm window, PL quantum yields exceeding 30%, and PL lifetimes of 300 μs or longer. These NPs, consisting of a Pluronic F127 shell and a core made up of assembled ncSi-OD kept apart by an octadecyl (OD) layer, were readily internalized into the cytosol, but not the nucleus, of NIH3T3 cells and were non-toxic. Asymmetrical field-flow fractionation (AF4) analysis was carried out to determine the size of the NPs in water. HiLyte Fluor 750 amine was linked via an amide link to NPs prepared with Pluronic-F127-COOH, as a first demonstration of functional NIR-emitting water dispersible ncSi-based nanoparticles.
authors.affiliation: WPI International Centre for Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan. SHIRAHATA.Naoto@nims.go.jp.
authors.forename: Sourov
authors.initials: S
authors.lastname: Chandra
authors.forename: Batu
authors.initials: B
authors.lastname: Ghosh
authors.forename: Grégory
authors.initials: G
authors.lastname: Beaune
authors.forename: Usharani
authors.initials: U
authors.lastname: Nagarajan
authors.forename: Takao
authors.initials: T
authors.lastname: Yasui
authors.forename: Jin
authors.initials: J
authors.lastname: Nakamura
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsuruoka
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Baba
authors.forename: Naoto
authors.initials: N
authors.lastname: Shirahata
authors.forename: Françoise M
authors.initials: FM
authors.lastname: Winnik
mesh_terms: D000818:Animals; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D041681:NIH 3T3 Cells; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055620:Optical Phenomena; D010316:Particle Size; D045663:Quantum Dots / Q000737:chemistry / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D019265:Spectroscopy, Near-Infrared
chemical_list: D012825:Silicon