title: Upconversion nanoparticles with a strong acid-resistant capping.
abstract: Water-dispersible upconversion nanoparticles (β-NaYF4:Yb(3+),Er(3+), UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to strong acidic conditions as low as pH 2. The additional functionality of the smart UCNP@COP nanosystem has been proved by its association to a well-known photosensitizer (namely, methylene blue, MB). The green-to-red emission ratio of the UC@COP@MB nanohybrid exhibits excellent linear dependence in the 7 to 2 pH range as a consequence of the release of the dye as the pH decreases.
authors.affiliation: Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain. maria.gonzalez@uv.es julia.perez@uv.es.
authors.forename: Ileana
authors.initials: I
authors.lastname: Recalde
authors.affiliation: Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain. maria.gonzalez@uv.es julia.perez@uv.es.
authors.forename: Nestor
authors.initials: N
authors.lastname: Estebanez
authors.affiliation: Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain. maria.gonzalez@uv.es julia.perez@uv.es.
authors.forename: Laura
authors.initials: L
authors.lastname: Francés-Soriano
authors.affiliation: Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas (IQOG-CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Liras
authors.affiliation: Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain. maria.gonzalez@uv.es julia.perez@uv.es.
authors.forename: María
authors.initials: M
authors.lastname: González-Béjar
authors.affiliation: Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán, 2, 46980 Paterna, Spain. maria.gonzalez@uv.es julia.perez@uv.es.
authors.forename: Julia
authors.initials: J
authors.lastname: Pérez-Prieto