title: NIR-to-NIR two-photon excited CaF2:Tm3+,Yb3+ nanoparticles: multifunctional nanoprobes for highly penetrating fluorescence bio-imaging.
abstract: In this study, we report on the remarkable two-photon excited fluorescence efficiency in the "biological window" of CaF(2):Tm(3+),Yb(3+) nanoparticles. On the basis of the strong Tm(3+) ion emission (at around 800 nm), tissue penetration depths as large as 2 mm have been demonstrated, which are more than 4 times those achievable based on the visible emissions in comparable CaF(2):Er(3+),Yb(3+) nanoparticles. The outstanding penetration depth, together with the fluorescence thermal sensitivity demonstrated here, makes CaF(2):Tm(3+),Yb(3+) nanoparticles ideal candidates as multifunctional nanoprobes for high contrast and highly penetrating in vivo fluorescence imaging applications.
authors.affiliation: Fluorescence Imaging Group, Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Ning-Ning
authors.initials: NN
authors.lastname: Dong
authors.forename: Marco
authors.initials: M
authors.lastname: Pedroni
authors.forename: Fabio
authors.initials: F
authors.lastname: Piccinelli
authors.forename: Giamaica
authors.initials: G
authors.lastname: Conti
authors.forename: Andrea
authors.initials: A
authors.lastname: Sbarbati
authors.forename: Juan Enrique
authors.initials: JE
authors.lastname: Ramírez-Hernández
authors.forename: Laura Martínez
authors.initials: LM
authors.lastname: Maestro
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Iglesias-de la Cruz
authors.forename: Francisco
authors.initials: F
authors.lastname: Sanz-Rodriguez
authors.forename: Angeles
authors.initials: A
authors.lastname: Juarranz
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Vetrone
authors.forename: John A
authors.initials: JA
authors.lastname: Capobianco
authors.forename: José García
authors.initials: JG
authors.lastname: Solé
authors.forename: Marco
authors.initials: M
authors.lastname: Bettinelli
authors.forename: Daniel
authors.initials: D
authors.lastname: Jaque
authors.forename: Adolfo
authors.initials: A
authors.lastname: Speghini
mesh_terms: D002124:Calcium Fluoride / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D005456:Fluorescent Dyes / Q000737:chemistry / Q000633:toxicity; D006367:HeLa Cells; D006801:Humans; D007259:Infrared Rays; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects; D057054:Molecular Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D010316:Particle Size; D017785:Photons; D013050:Spectrometry, Fluorescence; D013932:Thulium / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D013932:Thulium; D015018:Ytterbium; D002124:Calcium Fluoride