Cjr. Vanderoord et al., MICROVOLUME TIME-RESOLVED FLUORESCENCE SPECTROSCOPY USING A CONFOCAL SYNCHROTRON-RADIATION MICROSCOPE, Applied spectroscopy, 49(10), 1995, pp. 1469-1473
The confocal microscope SYCLOPS (SYCLOPS is not an acronym although th
e first syllable is derived from its main light source, a synchrotron
radiation source) at the Daresbury Science and Engineering Research Co
uncil (SERC) Laboratory, U.K., has been designed to facilitate fluores
cence decay measurements on microscopic volume elements. SYCLOPS utili
zes the Daresbury Synchrotron Radiation Source (SRS) as a pulsed light
source. Visible or UV excitation light is selected from the white syn
chrotron radiation spectrum with a bandpass filter matching the absorp
tion band of the fluorophores. Decay curves of fluorescence intensity
emitted by a pre-selected micro-volume in the sample can be acquired w
ith standard time-correlated single-photon counting techniques. The fl
uorescence intensity was collected from a confocal spot with a volume
of 3 mu m(3). The first lifetime measurements done with the instrument
were carried out on a coumestrol -dihydroxy-6H-benzofuro[3,2-c][I]ben
zopyran-6-one) solution and on different cellular compartments of livi
ng cells incubated with coumestrol.