DRAQ5 Revisited

Derek Davies daviesd2 at cancer.org.uk
Tue Mar 12 05:30:27 EST 2002

Well, DRAQ5 seems to be the flavour of the week - I speak as a
relatively new user of the dye and I am sure Paul Smith or Terry Hoy at
Cardiff are more qualified to answer but that has never stopped me
before, so...

On Mon, 11 Mar 2002, simon Monard wrote:
> Do you know how far in the red DRAQ5 emits, can you use it on a sorter
> as well as PE/Cy5 and collect the DRAQ5 above 710nm or something?

As far as I know the max emission of DRAQ5 is about 700nm but it extends
up to at least 800nm. I just did a quick and dirty experiment using
PE-CY5 and DRAQ5 with 488nm excitation - collecting PE-Cy5 through a
670/20 filter and DRAQ5 through a 700LP filter using a 710DCLP to
separate the signals, there was a bit of overlap of DRAQ5 into the
PE-CY5 channel which needed about 5% compesation, none needed the other
way but it was a relatively low PE-CY5 signal so maybe with a brigher
one it might be necessary. This was the only filter combination readily
to hand but it did look encouraging and I am sure with a little tweaking
of the filter set-up it can be done (there may be a trade off of a
slightly fatter DNA CV though). I'll get back to you when I have
explored it a bit more. How are the chickens by the way?

On Mon, 11 Mar 2002, Mostowski, Howard S. wrote:
> DRAQ5 sounds as the next best thing since sliced bread; therefore I
> have several questions.
> 1. From whom can it be purchased from [USA}?

Alexis Biochemicals (as in the UK)
6181 Cornerstone Ct. E., Ste 103
San Diego, CA

Tel: 800-900-0065
Fax: 800-900-9224
Email: alexis-usa at alexis-corp.com
Web: www.alexis-corp.com

> 2. Can it also be used as a live/dead discriminator, since
> it couples with DNA?

The staining of live cell DNA is very rapid, generally within 2-5mins,
so this rather means it hasnt proved that useful in our hands as a
live-dead discriminator.

> 3. Are there any dangers in handling namely carcinogenic?

It binds DNA so potentially harm,ful, take the usual precautions as when
handling these types of dyes. More information (including references)

Don Rosson asked about using the dye on large scale. I cant say that I
have done that but even in analytical experiments, we have seen that the
profiles are quite dye and cell concentration dependent. As a guide, I
get good HL60 profiles when using 5uM DRAQ to 10e6 cells. Changing
either dye or cell concentrations by a factor of 2 results in a worse CV
so I suspect that you would need to be quite careful as the optimal
range may be quite narrow.


Derek Davies                       Voice: (44) 020 7269 3394
FACS Laboratory,                   FAX: (44) 020 7269 3100
Cancer Research UK,                e_mail:derek.davies at cancer.org.uk
London Research Institute,	   mobile: 07790 604112
44 Lincolns Inn Fields,
London, UK.

Web Page: http://sci.cancerresearchuk.org/axp/facs/davies/index.html

In tenebris lux

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