Calibration beads containing luminescent lanthanide ion complexes

• Published in: Journal of Biomedical Optics 2009-03, Vol.14 (2), p.024022-024027
• Main Authors: Leif, Robert C, Yang, Sean, Jin, Dayong, Piper, James, Vallarino, Lidia M, Williams, John W, Zucker, Robert M
• Format: Article
• Language: English
• Subjects: Beads; Bleaching; Calibration; digital microscopy; europium; Excitation; Flow cytometry; Flow Cytometry - standards; lanthanide; Lanthanides; Lanthanoid Series Elements - analysis; Lanthanoid Series Elements - chemistry; Luminescence; Luminescent Measurements - standards; Microscopy; Microscopy, Fluorescence - standards; Microspheres; spectra; Spectrometry, Fluorescence - standards; time delayed
• ISSN: 1083-3668; 1560-2281
• DOI: 10.1117/1.3103646

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 beads containing a luminescent europium-complex are manufactured. The luminescence distribution of the 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 ), and with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation of the 0.5- and 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 , respectively. Thus, these 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.