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Proceedings Paper

Heterodyning of modulated pulses for fluorescence lifetime measurements in flow cytometry
Author(s): Bertram G. Pinsky; John J. Ladasky
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Paper Abstract

Heterodyning of modulated pulses in flow cytometry in the PMT offers three major advantages over external homodyning techniques: first, intermodulation distortion is reduced; second, the ability to choose a lower intermediate frequency for evaluating phase affords the opportunity to use digital signal processing techniques to measure phase; third, the limiters we used previously in homodyning phase measurement circuitry may be removed, thereby reducing phase distortion. We constructed a heterodyning PMT base capable of providing an intermediate frequency of 1 MHz, and installed it on our phase flow cytometer (PFC). The fluorescence lifetime of 2 micrometers Fluoresbrite yellow beads was approximately 3 to 4 ns on the heterodyning system, which compares well to the 3.5 ns measured with the original homodyning PFC electronics. This lifetime parameter, when coupled with recently-developed lifetime-based probes for Ca2+ and pH, provides new opportunities in flow cytometry for study of intensity-independent intracellular physiology.

Paper Details

Date Published: 17 August 1994
PDF: 6 pages
Proc. SPIE 2137, Time-Resolved Laser Spectroscopy in Biochemistry IV, (17 August 1994); doi: 10.1117/12.182706
Show Author Affiliations
Bertram G. Pinsky, Becton Dickinson Immunocytometry Systems (United States)
John J. Ladasky, Becton Dickinson Immunocytometry Systems (United States)

Published in SPIE Proceedings Vol. 2137:
Time-Resolved Laser Spectroscopy in Biochemistry IV
Joseph R. Lakowicz, Editor(s)

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