UV LED excited time-resolved fluorescence microscope

Russell Connally, Dayong Jin, Jim Piper, Tom Lawson

Research output: Contribution to journalMeeting abstractpeer-review


Many naturally occurring substances are intrinsically fluorescent (autofluorescent) when exited at an appropriate wavelength and emission can occur throughout the visible spectrum. Autofluorescence is typically a short-lived phenomena with a lifetime (t) measured in nanoseconds and this property is exploited in Time-Resolved Fluorescence (TRF) microscopy to enhance detection of labelled pathogens against autofluorescence background. The TRF methods are based on the use of immunofluorescent labels with long fluorescence lifetimes (~600 μs) to ensure that labelled target is viable long after short-lived autofluorescence has faded. Pulsed excitation is used to excite fluorescence from the sample and this is followed by a gate-delay phase to permit decay of short-lived fluorescence. When flashlamps are used as the excitation source, the gate-delay period must be extended (>50 μs) to ensure that light from the decaying plasma has decayed to zero. The extended gate-delay results in a significant loss of fluorescence intensity from the synthetic label and this is avoided with solidstate excitation sources. A high-power (>100 mW) Light Emitting Diodes (LEDS) (λ 365 nm) was substituted for the flashlamp and found to give excellent background suppression and strong label fluorescence compared to flashlamp excitation.
Original languageEnglish
Pages (from-to)724-725
Number of pages2
JournalCytometry Part A
Issue number8
Publication statusPublished - Aug 2009
Event14th Leipziger Workshop/7th International Workshop on Slide Based Cytometry - Leipzig, Germany
Duration: 2 Apr 20094 Apr 2009

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