Dave Parks and I spent some time looking at loss of fluorescence of PE to try to figure out why low power Fascans did better than high power jet-in-air sorters at measuring PE stained cells. We determined the PE saturation curve and found that the dye saturated significatly at 100mW. Moreover, we observed that with several hundred milliwatts of 488nm illumination, PE was kicked into some unusal state from which it didn't recover. Re-analysis of sorted cells minutes later had lost up to 45% of their origional fluorescence. With less laser illumination, this effect was minimized. For FITC we did not notice much change - 5% at most. We did not look at Cy5PE at that time. >From our experience we would expect that with the low laser power that you are using (15mW) the losses for FITC and PE will be small. -Marty Bigos Stanford Shared FACS Facility
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:49:22 EST