[Histonet] Sirius red stain - picric acid substitute - water -really?

[Amos Brooks]

Hi Mia,
     In response to your question about the need for picric acid in the
sirus red solution. Yes, you do need it. The article you listed was working
with collagen gels and not actually tissue sections. If you omit the picric
acid you not only loose the yellow counter stain as mentioned in the
article, but the sirius red dye binds to other tissue components. It is also
critical that the pH of the solution be between 2.0 and 2.3 (picric acid or
not) in order for the staining to be specific to these collagen types. If
you decide to try this please do so in parallel with the established picric
acid technique and certainly make sure that the water is buffered to the
necessary pH. I have a great article back in the lab about the stain and how
it differentially stains the collagen types and bifringes to further
differentiate them. It's a bit old, but definitely still relevant.
     Now I know there are some folks out there that will inevitably whine
that picric acid is a hazardous chemical and shouldn't be used in the lab.
Well guys it's a lab, that's just the way it goes. As long as you are
conscious of the hazards involved, store, use and dispose of it correctly it
can easily be used relatively safely. We all use gas in our car's gas tanks,
and that is an extremely hazardous chemical. And some of us travel 75 MPH on
the highway while texting and eating McDonalds with our kids fighting in the
back seat. Being on the road with those folks is scarier than a bit of
properly used picric acid. Just as you watch for that swerving minivan and
use your car carefully, respect and use chemicals carefully and everything
will be just fine.

Amos Brooks

On Wed, Feb 23, 2011 at 10:52 AM, <histonet-request <@t> lists.utsouthwestern.edu
> wrote:

> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Mia
> Woodruff
> Sent: Tuesday, February 22, 2011 10:33 PM
> To: histonet <@t> lists.utsouthwestern.edu
> Subject: [Histonet] Sirius red stain - picric acid substitute - water
> -really?
>
> Hello all,
>
> I have been undertaking sirius red staining using picric acid, I was under
> the
> impression (from papers) that picric acid is an important component of the
> procedure and read that it prevents non-specific binding of the dye to
> things
> other than collagen. However,  I have recently found a paper which suggests
> I
> can simply use water instead of picric acid, seems quite a long shot but I
> wondered if anyone has experience with the water technique- given that
> picric
> acid is pretty dangerous I would be keen to move away from using it but
> only if
> scientifically sound to do so. I don't want to jeopardize my results but if
> this
> method works then it's a far safer and cheaper safer approach. Any advice?
>
> Paper: A specific quantitative assay for collagen synthesis by cells seeded
> in
> collagen-based biomaterials using sirius red F3B precipitation
> LEE D.A.; ASSOKU E.; DOYLE V. Journal of Materials Science: Materials in
> Medicine<http://www.ingentaconnect.com/content/klu/jmsm>, Volume 9, Number
> 1,
> 1998 , pp. 47-51(5)
>
>
> Many thanks
> Mia
>