title: Low-temperature approach to highly emissive copper indium sulfide colloidal nanocrystals and their bioimaging applications.
abstract: We report our newly developed low-temperature synthesis of colloidal photoluminescent (PL) CuInS2 nanocrystals (NCs) and their in vitro and in vivo imaging applications. With diphenylphosphine sulphide (SDPP) as a S precursor made from elemental S and diphenylphosphine, this is a noninjection based approach in 1-dodecanethiol (DDT) with excellent synthetic reproducibility and large-scale capability. For a typical synthesis with copper iodide (CuI) as a Cu source and indium acetate (In(OAc)3) as an In source, the growth temperature was as low as 160 °C and the feed molar ratios were 1Cu-to-1In-to-4S. Amazingly, the resulting CuInS2 NCs in toluene exhibit quantum yield (QY) of ~23% with photoemission peaking at ~760 nm and full width at half maximum (FWHM) of ~140 nm. With a mean size of ~3.4 nm (measured from the vertices to the bases of the pyramids), they are pyramidal in shape with a crystal structure of tetragonal chalcopyrite. In situ (31)P NMR (monitored from 30 °C to 100 °C) and in situ absorption at 80 °C suggested that the Cu precursor should be less reactive toward SDPP than the In precursor. For our in vitro and in vivo imaging applications, CuInS2/ZnS core-shell QDs were synthesized; afterwards, dihydrolipoic acid (DHLA) or 11-mercaptoundecanoic acid (MUA) were used for ligand exchange and then bio-conjugation was performed. Two single-domain antibodies (sdAbs) were used. One was 2A3 for in vitro imaging of BxPC3 pancreatic cancer cells. The other was EG2 for in vivo imaging of a Glioblastoma U87MG brain tumour model. The bioimaging data illustrate that the CuInS2 NCs from our SDPP-based low-temperature noninjection approach are good quality.
authors.affiliation: Emerging Technologies, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada. kui.yu@nrc.ca
authors.forename: Kui
authors.initials: K
authors.lastname: Yu
authors.forename: Peter
authors.initials: P
authors.lastname: Ng
authors.forename: Jianying
authors.initials: J
authors.lastname: Ouyang
authors.forename: Md Badruz
authors.initials: MB
authors.lastname: Zaman
authors.forename: Abedelnasser
authors.initials: A
authors.lastname: Abulrob
authors.forename: Toya Nath
authors.initials: TN
authors.lastname: Baral
authors.forename: Dorothy
authors.initials: D
authors.lastname: Fatehi
authors.forename: Zygmunt J
authors.initials: ZJ
authors.lastname: Jakubek
authors.forename: David
authors.initials: D
authors.lastname: Kingston
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Wu
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Liu
authors.forename: Charlie
authors.initials: C
authors.lastname: Hebert
authors.forename: Donald M
authors.initials: DM
authors.lastname: Leek
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Whitfield
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003080:Cold Temperature; D003102:Colloids / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D005909:Glioblastoma / Q000737:chemistry*; D006801:Humans; D007204:Indium / Q000737:chemistry*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging / Q000295:instrumentation* / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D003102:Colloids; D013440:Sulfides; D007204:Indium; D003300:Copper