title: Microwave-assisted synthesis of biocompatible europium-doped calcium hydroxyapatite and fluoroapatite luminescent nanospindles functionalized with poly(acrylic acid).
abstract: Europium-doped calcium hydroxyapatite and fluoroapatite nanophosphors functionalized with poly(acrylic acid) (PAA) have been synthesized through a one-pot microwave-assisted hydrothermal method from aqueous basic solutions containing calcium nitrate, sodium phosphate monobasic, and PAA, as well as sodium fluoride in the case of the fluoroapatite particles. In both cases a spindlelike morphology was obtained, resulting from an aggregation process of smaller subunits which also gave rise to high specific surface area. The size of the nanospindles was 191 (32) × 40 (5) nm for calcium hydroxyapatite and 152 (24) × 38 (6) nm for calcium fluoroapatite. The luminescent nanoparticles showed the typical red luminescence of Eu(3+), which was more efficient for the fluoroapatite particles than for the hydroxyapatite. This is attributed to the presence of OH(-) quenchers in the latter. The nanophosphors showed negligible toxicity for Vero cells. Both PAA-functionalized nanophosphors showed a very high (up to at least 1 week) colloidal stability in 2-(N-morpholino)ethanesulfonic acid (MES) at pH 6.5, which is a commonly used buffer for physiological pH. All these features make both kinds of apatite-based nanoparticles promising tools for biomedical applications, such as luminescent biolabels and tracking devices in drug delivery systems.
authors: Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Calle Américo Vespucio 49, E- 41092 Seville, Spain. aescudero@icmse.csic.es
authors: Alberto
authors: A
authors: Escudero
authors: Mauricio E
authors: ME
authors: Calvo
authors: Sara
authors: S
authors: Rivera-Fernández
authors: Jesús M
authors: JM
authors: de la Fuente
authors: Manuel
authors: M
authors: Ocaña
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D002021:Buffers; D002470:Cell Survival / Q000187:drug effects; D060326:Chemistry Techniques, Synthetic; D002522:Chlorocebus aethiops; D017886:Durapatite / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D049408:Luminescent Agents / Q000737:chemistry; D008872:Microwaves; D053758:Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D014709:Vero Cells
chemical_list: D000180:Acrylic Resins; D001031:Apatites; D001672:Biocompatible Materials; D002021:Buffers; D049408:Luminescent Agents; D009942:Organometallic Compounds; D005063:Europium; C006903:carbopol 940; D017886:Durapatite; C025105:fluorapatite