title: Calibration beads containing luminescent lanthanide ion complexes.
abstract: The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, would be enhanced by the availability of narrowband emitting, UV excited lanthanide calibration beads. 0.5-, 3-, and 5-microm beads containing a luminescent europium-complex are manufactured. The luminescence distribution of the 5-microm beads is measured with a time-delayed light-scatter-gated luminescence flow cytometer to have a 7.0% coefficient of variation (CV) The spacial distribution of the europium-complex in individual beads is determined to be homogeneous by confocal microscopy. Emission peaks are found at 592, 616 (width 9.9 nm), and 685 nm with a PARISS spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation of the 0.5- and 5-microm beads measured under LED excitation with a fluorescence microscope indicate that bleaching does not interfere with their imaging. The luminescence lifetimes in water and air were 340 and 460 micros, respectively. Thus, these 5-microm beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells.
authors.affiliation: Newport Instruments, 5648 Toyon Road, San Diego, California 92115-1022, USA. rleif@rleif.com
authors.forename: Robert C
authors.initials: RC
authors.lastname: Leif
authors.forename: Sean
authors.initials: S
authors.lastname: Yang
authors.forename: Dayong
authors.initials: D
authors.lastname: Jin
authors.forename: James
authors.initials: J
authors.lastname: Piper
authors.forename: Lidia M
authors.initials: LM
authors.lastname: Vallarino
authors.forename: John W
authors.initials: JW
authors.lastname: Williams
authors.forename: Robert M
authors.initials: RM
authors.lastname: Zucker
mesh_terms: D002138:Calibration; D005434:Flow Cytometry / Q000592:standards*; D028581:Lanthanoid Series Elements / Q000032:analysis* / Q000737:chemistry*; D008163:Luminescent Measurements / Q000592:standards*; D008856:Microscopy, Fluorescence / Q000592:standards*; D008863:Microspheres; D013050:Spectrometry, Fluorescence / Q000592:standards*
chemical_list: D028581:Lanthanoid Series Elements