Time-Gated Luminescence Microscopy

Authors

  • Russell E. Connally,

    1. Centre for Laser Applications, Department of Physics, Division of Information and Communication Sciences, Macquarie University, Sydney, Australia
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  • James A. Piper

    1. Centre for Laser Applications, Department of Physics, Division of Information and Communication Sciences, Macquarie University, Sydney, Australia
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Address for correspondence: Russell E. Connally, Centre for Laser Applications, Department of Physics, Division of Information and Communication Sciences, Macquarie University, Sydney, NSW 2109, Australia.
rconnall@ics.mq.edu.au

Abstract

Autofluorescent algal samples were spiked with europium beads for analysis on a novel all-solid-state, time-gated luminescence (TGL) microscope. Pulsed UV excitation (365 nm) was provided by a high-power UV-LED source fitted to an Olympus BX51 microscope. An “Impactron” electron multiplying charge-coupled-device (CCD) camera acquired images in delayed luminescence mode. Second, we evaluated sensitivity of the instrument by acquiring images of immunofluorescently labeled Giardia cysts with a single-exposure period of 3 ms. The camera was triggered 3 μs after the LED had extinguished to yield a 14-fold increase in signal-to-noise ratio within a single 33 ms capture cycle. This novel instrument could be switched instantly from prompt epifluorescence mode to TGL mode for suppression of short-lived fluorescence.

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