{Disarmed} RE: Choosing filter configurations for Qdots in Flow

Ian Dimmick ian.dimmick at newcastle.ac.uk
Fri Jun 15 04:28:42 EDT 2007

Some rules for Q dots, generally speaking the compensation required is less than for conventional fluorochroomes , remember the Q dots are excited by any laser so you need not only consider what filters you have on a specific laser , but possibly more importantly , what similar filters you have on other laser lines. 
I would always take the option of collecting more signal, although the extinction coefficient of the Q dots is relatively high the rate defining step very often is the antigen concentration on your cell , so you need to optimise signal in cases where antigen expression is just above autofluorescence. 
To give definitive answers regarding filters means a lot more information is required as to laser power, type of cells etc, however I have found that Q dots will fit in to most filter configurations rather than re configuring the instrument specifically for the Q dots, then perhaps having to re configure things for conventional fluorochromes
Ian Dimmick
Flow Cytometry Core Facility Manager
North East England Stem Cell Institute
Bioscience Centre
International Centre for life
Newcastle Upon Tyne
Ian.Dimmick at ncl.ac.uk
Tel 0044 191 2418831
Fax 0044 191 2418666
(mob) 0044 7970344823


De: Roberts Joanna [mailto:joanna.roberts at epfl.ch]
Enviado el: jue 14-jun-07 16:11
Para: Cytometry Mailing List
Asunto: Choosing filter configurations for Qdots in Flow


Dear Flow Cytometry Community, 


I have a question about filter configurations for Qdots in flow cytometry. 


I would like to order a new instrument with a violet laser to measure the full range of qdot fluorochromes. From quick talks with BD, I have a list of the filters they suggest. They represent slightly narrower signal ranges in just about all cases than the filters used by the fellows in the paper by Chattopadhyay et al in Nature Immunology last year. 


For those of you working with these reagents in flow, could you offer your opinion on this matter? Would you recommend collecting more signal (and probably doing a bit more 'inter-qdot' compensation) or would you suggest taking the narrower band pass, collecting less signal and needing less compensation? 


Here is a list of the bandpass filters suggested from BD as well as those used in the paper mentioned above. 


		     Chattopadhyay et al       Suggestion from BD

QDOT800 	780/60 (750LP)		800/30

QDOT705 	705/70 (670LP)		710/50

QDOT655 	660/40 (640LP)		660/20

QDOT605 	605/40 (595LP)		610/20

QDOT585 	585/42 (570LP)		585/42

QDOT565 	560/40 (557LP)		560/40

QDOT525 	515/20			     525/50



Any and all recommendations, ideas and advice are appreciated. 


Thanks a lot to the organisers and moderators who run this list and all the people who take the time to dish out their 2 cents- it is great!


Best wishes, 



Flow Cytometry Core Facility

EPFL, Swiss Federal Institute of Technology

SV-SG, Station 15

CH 1015, Lausanne



+41 21 69 39 547


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