Installation of yellow HeNe laser on the Compucyte laser scanning cytometer.
The Compucyte laser scanning cytometer (LSC) normally uses a red HeNe laser for the excitation of APC, APC tandems and low molecular weight fluorochromes such as Cy5 and Alexa Fluor 647. However, the insensitivity of the human eye for wavelengths above 650 nm makes these red-excited probes less applicable for epifluorescence and confocal microscopy. Green- and yellow-excited fluorochromes such as Cy3, Alexa Fluor 532, 546 and 555, and Texas Red and Alexa Fluor 594 see frequent use in fluorescence microscopy; the yellow-excited probes in particular are bright and well-separated from fluorescein. Since many users want to transfer their microscopy applications to the LSC, we have adapted a yellow HeNe laser emitting at 594 nm in place of the traditional red HeNe, allowing the use of Texas Red or Alexa Fluor 594 as well as APC and its tandems.
(Below). Yellow HeNe laser on the LSC. A Melles Griot yellow HeNe laser emitting at 4 mW was installed in the red HeNe position on the LSC, and aligned with the argon laser.
(Below). Yellow HeNe laser on the LSC. Yellow HeNe laser (left) and argon-ion laser (right) working in tandem.
(Below). Analysis of sensitivity bead cocktail using the yellow HeNe laser. A Molecular Probes InSpeck Deep Red bead cocktail (including unlabeleds, 1, 3, 10, 30 and 100% components) were analyzed on the LSC using long red fluorescence as contouring parameter. Beads were analyzed through the 650 LP filter in the FL4 position. The dimmest bead populations were easily distinguishable on the LSC (the unlabeled bead population was not contoured on and is not visible).
