Time-gated luminescence microscopy allowing direct visual inspection of lanthanide-stained microorganisms in background-free condition

Jin, D; Piper, JA

Time-gated luminescence microscopy allowing direct visual inspection of lanthanide-stained microorganisms in background-free condition

Jin, D

Piper, JA

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Publication Type:: Journal Article
Citation:: Analytical Chemistry, 2011, 83 (6), pp. 2294 - 2300
Issue Date:: 2011-03-15

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Field	Value	Language
dc.contributor.author	Jin, D https://orcid.org/0000-0003-1046-2666	en_US
dc.contributor.author	Piper, JA	en_US
dc.date.issued	2011-03-15	en_US
dc.identifier.citation	Analytical Chemistry, 2011, 83 (6), pp. 2294 - 2300	en_US
dc.identifier.issn	0003-2700	en_US
dc.identifier.uri	http://hdl.handle.net/10453/110800
dc.description.abstract	Application of standard immuno-fluorescence microscopy techniques for detection of rare-event microorganisms in dirty samples is severely limited by autofluorescence of nontarget organisms or other debris. Time-gated detection using gateable array detectors in combination with microsecond- lifetime luminescent bioprobes (usually lanthanide-based) is highly effective in suppression of (nanosecond-lifetime) autofluorescence background; however, the complexity and cost of the instrumentation is a major barrier to application of these techniques to routine diagnostics. We report a practical, low-cost implementation of time-gated luminescence detection in a standard epifluorescence microscope which has been modified to include a high-power pulsed UV light-emitting diode (LED) illumination source and a standard fast chopper inserted in the focal plane behind amicroscope eyepiece. Synchronization of the pulsed illumination/gated detection cycle is driven from the clock signal fromthe chopper. To achieve time-gated luminescence intensities sufficient for direct visual observation, we use high cycle rates, up to 2.5 kHz, taking advantage of the fast switching capabilities of the LED source. We have demonstrated real-time direct-visual inspection of europium-labeled Giardia lamblia cysts in dirty samples and Cryptosporidium parvum oocysts in fruit juice concentrate. The signal-tobackground ratio has been enhanced by a factor of 18 in time-gatedmode.The availability of low-cost, robust time-gatedmicroscopes will aid development of long-lifetime luminescence bioprobes and accelerate their application in routine laboratory diagnostics. © 2011 American Chemical Society.	en_US
dc.relation.ispartof	Analytical Chemistry	en_US
dc.relation.isbasedon	10.1021/ac103207r	en_US
dc.subject.classification	Analytical Chemistry	en_US
dc.subject.mesh	Cryptosporidium parvum	en_US
dc.subject.mesh	Giardia lamblia	en_US
dc.subject.mesh	Fruit	en_US
dc.subject.mesh	Lanthanoid Series Elements	en_US
dc.subject.mesh	Microscopy	en_US
dc.subject.mesh	Luminescent Measurements	en_US
dc.subject.mesh	Staining and Labeling	en_US
dc.subject.mesh	Soil Microbiology	en_US
dc.subject.mesh	Time Factors	en_US
dc.subject.mesh	Beverages	en_US
dc.title	Time-gated luminescence microscopy allowing direct visual inspection of lanthanide-stained microorganisms in background-free condition	en_US
dc.type	Journal Article
utslib.citation.volume	6	en_US
utslib.citation.volume	83	en_US
utslib.for	0301 Analytical Chemistry	en_US
utslib.for	0399 Other Chemical Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - IBMD - Initiative for Biomedical Devices
utslib.copyright.status	closed_access
pubs.issue	6	en_US
pubs.publication-status	Published	en_US
pubs.volume	83	en_US

Abstract:

Application of standard immuno-fluorescence microscopy techniques for detection of rare-event microorganisms in dirty samples is severely limited by autofluorescence of nontarget organisms or other debris. Time-gated detection using gateable array detectors in combination with microsecond- lifetime luminescent bioprobes (usually lanthanide-based) is highly effective in suppression of (nanosecond-lifetime) autofluorescence background; however, the complexity and cost of the instrumentation is a major barrier to application of these techniques to routine diagnostics. We report a practical, low-cost implementation of time-gated luminescence detection in a standard epifluorescence microscope which has been modified to include a high-power pulsed UV light-emitting diode (LED) illumination source and a standard fast chopper inserted in the focal plane behind amicroscope eyepiece. Synchronization of the pulsed illumination/gated detection cycle is driven from the clock signal fromthe chopper. To achieve time-gated luminescence intensities sufficient for direct visual observation, we use high cycle rates, up to 2.5 kHz, taking advantage of the fast switching capabilities of the LED source. We have demonstrated real-time direct-visual inspection of europium-labeled Giardia lamblia cysts in dirty samples and Cryptosporidium parvum oocysts in fruit juice concentrate. The signal-tobackground ratio has been enhanced by a factor of 18 in time-gatedmode.The availability of low-cost, robust time-gatedmicroscopes will aid development of long-lifetime luminescence bioprobes and accelerate their application in routine laboratory diagnostics. © 2011 American Chemical Society.

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http://hdl.handle.net/10453/110800