Phase-sensitive flow cytometer
First Claim
1. A phase-sensitive flow cytometer for resolving fluorescence emissions from fluorochrome labeled cells into two components, comprising:
- flow cytometer means for providing a flow steam containing said labeled cells;
an excitation light for exciting said labeled cells to fluoresce in said flow stream;
modulation means for modulating said excitation light and generating a reference signal at a selected modulation frequency;
detector means for receiving fluorescence emission spectra from said labeled cells as a modulated fluorescence signal and outputting a modulated intensity signal functionally related to said fluorescence emission spectra from said labeled cells; and
phase detector means for resolving said modulated intensity signal into two signal components, each functionally related to a different fluorescence decay lifetime of said fluorescent emission spectra.
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Abstract
A phase-sensitive flow cytometer (FCM) provides additional FCM capability to use the fluorescence lifetime of one or more fluorochromes bound to single cells to provide additional information regarding the cells. The resulting fluorescence emission can be resolved into individual fluorescence signals if two fluorochromes are present or can be converted directly to a decay lifetime from a single fluorochrome. The excitation light for the fluorochromes is modulated to produce an amplitude modulated fluorescence pulse as the fluorochrome is excited in the FCM. The modulation signal also forms a reference signal that is phase-shifted a selected amount for subsequent mixing with the output modulated fluorescence intensity signal in phase-sensitive detection circuitry. The output from the phase-sensitive circuitry is then an individual resolved fluorochrome signal or a single fluorochrome decay lifetime, depending on the applied phase shifts.
100 Citations
4 Claims
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1. A phase-sensitive flow cytometer for resolving fluorescence emissions from fluorochrome labeled cells into two components, comprising:
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flow cytometer means for providing a flow steam containing said labeled cells; an excitation light for exciting said labeled cells to fluoresce in said flow stream; modulation means for modulating said excitation light and generating a reference signal at a selected modulation frequency; detector means for receiving fluorescence emission spectra from said labeled cells as a modulated fluorescence signal and outputting a modulated intensity signal functionally related to said fluorescence emission spectra from said labeled cells; and phase detector means for resolving said modulated intensity signal into two signal components, each functionally related to a different fluorescence decay lifetime of said fluorescent emission spectra. - View Dependent Claims (2)
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3. A phase sensitive flow cytometer for determining the fluorescence decay lifetime of a fluorescence emission, comprising:
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flow cytometer means for providing a flow stream containing cells labeled with a fluorochrome; an excitation light for exciting said fluorochrome to fluoresce in said flow stream; modulation means for modulating said excitation light and generating a reference signal at a selected modulation frequency; detector means for receiving a fluorescence emission spectra from said fluorochrome as a modulated fluorescence signal and outputting a modulated intensity signal functionally related to said fluorescence emission spectra from said fluorochrome; and phase detector means for inputting said modulated intensity signal and outputting two phase shifted signals whose ratio is functionally related to said fluorescence lifetime. - View Dependent Claims (4)
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Specification