title: Polypeptide-functionalized NaYF4:Yb(3+),Er(3+) nanoparticles: red-emission biomarkers for high quality bioimaging using a 915 nm laser.
abstract: We prepared poly-L-aspartic acid (PASP) functionalized NaYF4:Yb(3+),Er(3+) upconversion nanoparticles (UCNP-PASP). These nanoparticles can give red upconversion emission under excitation at 915 nm, whose wavelength of emission and excitation is located in the optical window of biological tissue. Dynamic laser scatting and zeta potentials of UCNP-PASP were used to study their stabilities in different aqueous solution. To understand the mechanism of the red emission of UCNP-PASP, photoluminescence spectra of samples were recorded before and after modification with PASP, poly acrylic acid (PAA), and poly(ether imide) (PEI) ligands under excitation at 915 and 980 nm, respectively. The cytotoxicity of the UCNP-PASP was also examined on a A549 cell and KB cell by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. Moreover, the PASP-functionalized UCNP was employed as a potential biomarker for in vitro and in vivo experiments of upconversion luminescence imaging.
authors.affiliation: School of Chemistry & Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing 210093, China.
authors.forename: Ao
authors.initials: A
authors.lastname: Xia
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Deng
authors.forename: Huan
authors.initials: H
authors.lastname: Shi
authors.forename: Jin
authors.initials: J
authors.lastname: Hu
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Shishan
authors.initials: S
authors.lastname: Wu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Huang
authors.forename: Jian
authors.initials: J
authors.lastname: Shen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D016923:Cell Death; D045744:Cell Line, Tumor; D003952:Diagnostic Imaging / Q000379:methods*; D004871:Erbium / Q000737:chemistry*; D005260:Female; D005459:Fluorides / Q000737:chemistry*; D006801:Humans; D007279:Injections, Subcutaneous; D007834:Lasers; D049449:Luminescence; D008819:Mice, Nude; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D015018:Ytterbium / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D010455:Peptides; C525362:sodium yttriumtetrafluoride; C017645:polyaspartate; D015019:Yttrium; D004871:Erbium; D015018:Ytterbium; D005459:Fluorides
keywords: NaYF4; bioimaging; poly-l-aspartic acid; polypeptide; upconversion luminescence