title: Inert phosphorescent nanospheres as markers for optical assays.
abstract: A simple encapsulation technique is presented to produce highly phosphorescent, inert nanospheres that are suitable luminescent markers. It is based on the coprecipitation of phosphorescent ruthenium(II)-tris(polypyridyl) complexes and polyacrylonitrile (PAN) derivatives from a solution in N,N-dimethylformamide. The beads precipitate in the form of very small aggregates of spherical shape and a typical particle diameter of less than 50 nm. This process allows the encapsulation of phosphorescent and fluorescent dyes in an individual nanosphere provided that they are sufficiently lipophilic. Quenching by oxygen is negligible due to the use of PAN. The nanospheres were characterized with respect to their spectral properties (quantum yields of the luminophores, brightness, luminescence decay time), stability in aqueous buffered suspensions, and in terms of size, shape, and surface charge of the particles, as well as storage stability, quenching by oxygen, and dye leaching.
authors.affiliation: Institute of Analytical Chemistry, Chemo- and Biosensors, and Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Kürner
authors.forename: I
authors.initials: I
authors.lastname: Klimant
authors.forename: C
authors.initials: C
authors.lastname: Krause
authors.forename: H
authors.initials: H
authors.lastname: Preu
authors.forename: W
authors.initials: W
authors.lastname: Kunz
authors.forename: O S
authors.initials: OS
authors.lastname: Wolfbeis
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004339:Drug Compounding; D005456:Fluorescent Dyes; D008163:Luminescent Measurements; D008854:Microscopy, Electron; D008863:Microspheres; D036103:Nanotechnology; D009942:Organometallic Compounds; D010316:Particle Size; D012428:Ruthenium / Q000737:chemistry*; D012542:Scattering, Radiation; D013057:Spectrum Analysis
chemical_list: D000180:Acrylic Resins; D005456:Fluorescent Dyes; D009942:Organometallic Compounds; C010504:polyacrylonitrile; D012428:Ruthenium