Calibration beads containing luminescent lanthanide ion complexes

Robert C. Leif, Dayong Jin, James Piper, Lidia M. Vallarino, John W. Williams, Sean Yang, Robert M. Zucker

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

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The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including microscopes. Methods: 0.5, 3, and 5 micron (μm) beads containing a luminescent europium-complex were manufactured and the luminescence distribution of the 5 μm beads was measured with a time-delayed luminescence flow cytometer and a timedelayed digital microscope. The distribution of the luminescence intensity from the europium-complex in individual beads was determined on optical sections by confocal microscopy. The emission spectra of the beads under UV excitation were determined with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation were measured under LED excitation with a fluorescence microscope. Results: The kinetics of UV bleaching were very similar for the 0.5, 3, and 5 μm beads. Emission peaks were found at 592, 616, and 685 nanometers (nm). The width of the principal peak at half-maximum (616 nm) was 9.9 nm. The luminescence lifetimes in water and in air were 340 and 460 microseconds (μs), respectively. The distribution of the europium- complex in the beads was homogeneous. Conclusions: The 5 μm 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.

Original languageEnglish
Title of host publicationImaging, manipulation, and analysis of biomolecules, cells, and tissues VI
EditorsDaniel L. Farkas, Dan V. Nicolau, Robert C. Leif
Place of PublicationBellingham, Washington
Number of pages9
ISBN (Print)9780819470348
Publication statusPublished - 2008
EventImaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues VI - San Jose, CA, United States
Duration: 21 Jan 200823 Jan 2008

Publication series

NameProceedings of SPIE
ISSN (Print)1605-7422


OtherImaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues VI
Country/TerritoryUnited States
CitySan Jose, CA

Bibliographical note

Copyright 2008 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • beads
  • digital microscopy
  • europium
  • lanthanide
  • Luminescence
  • spectra
  • standard
  • time-delay


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