laurie_stojanovic@baxter.com wrote: > Has anyone out there used a Becton Dickinson FACScan or FACSort flow > cytometer to analyze platelet- or WBC-derived microparticles (0.2-1.0 um in > size)? I am looking for assistance in the following arenas: > 1. Distinguishing background (noise) events from "real" microparticle > events; looking for ways to increase the limit of sensitivity of these > instruments (Becton Dickinson Suggests limit is 0.5 to 1.0 um). > 2. Setting used during acquisition; especially, threshold trigger (FSC > or FL) and values thereof > 3. Gating strategies > 4. Sample collection and staining Laurie, Can't say on the BD, since I haven't tried, but I have done similar analysis on my Coulter equipment (Elite ESP and EPICS XL). I think that the suggested limit of about 0.5um may apply . . . you have to try it. I do know that I was able to resolve a 0.1um particle on my XL (the Elite had a limit of about 0.2um), but that was using a fluorescent particle. Triggering on fluorescence will dramatically improve your ability to resolve these smaller particles, providing the fluorescence is bright. (I think a limiting factor here is size as well . . . smaller particles by default carry lower amts. of dye, so don't achieve a high enough total fluorescence to resolve over background) You need to run your particle suspension buffer to establish background, then look for a particle peak greater that that defined limit using a live gate. Hope this moves you in the right direction. MAK. -- Mark A. KuKuruga, Managing Director University of Michigan Core Flow Cytometry kukuruga@medmail.med.umich.edu
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