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.

Automated detection of rare‐event pathogens through time‐gated luminescence scanning microscopy

“…The averaged intensity of 69.1 V corresponds to signal-to-background ratio of 21.6. However, this CV value of 27% was larger than the original value of 7% as measured by the time-gated luminescent flow cytometry (3,22). We attribute the relatively large CV of the prototype to the position difference of targeted cells.…”

“…The unique europium-containing calibration bead was reported with the excitation peak wavelength at $ 370 nm, the narrow-band emission near 620 nm with a very low coefficient of variation (CV) of 7.0% (22). In aqueous suspension, it has a luminescence lifetime of 320 AE 30 ls, which is sufficiently long for evaluation purpose.…”

On-the-fly decoding luminescence lifetimes in the microsecond region for lanthanide-encoded suspension arrays

“…A trivalent europium complex of thenoyltrifluoroacetonate Eu(TTFA) 3 4849 and a hexafluorophosphate salt of cationic coumarin50 were encapsulated into porous polystyrene beads as donor and acceptor dyes, using a simple method of solvent swelling (see Methods section). When in close proximity, a proportion of excited Eu 3+ complexes in the beads non-radiatively transferred energy to the acceptor dyes5152, as a result of the spectral overlap between the donor emission and the acceptor excitation (see Supplementary Fig.…”

Cytometric investigation of rare-events featuring time-gated detection and high-speed stage scanning

“…They are europium-contained 5.0 Pm diameter polymer beads, being excited at ~370 nm and emitting near 620 nm, with a very low CV of 7.0% reported in literature [2,5]. The beads suspension IQEC/CLEO Pacific Rim 2011 • 28 August -1 September 2011 • Sydney, Australia 978-0-9775657-7-1 © 2011 AOS was diluted and mixed with 2.5% polyvinyl alcohol (PVA), followed by vortexing and ultrasonicating to remove aggregation.…”

“…FireRed TM calibration beads (Newport Instruments, San Diego, CA) were used to mimic rare-events for evaluation of the instrument [5]. They are europium-contained 5.0 Pm diameter polymer beads, being excited at ~370 nm and emitting near 620 nm, with a very low CV of 7.0% reported in literature [2,5].…”