[Histonet] tissue coming off slides

[Monfils, Paul]

There is the venerable old technique, seldom used today, of coating the
slide with celloidin, also known as parlodion. The technique isn't used much
today, partially because electrostatically charged slides have solved many
of the adherence problems, and partially because the technique requires
ethyl ether, which is forbidden by many institutions today because of its
extreme flammability.  But what we used to do is make up a solution of
celloidin in 1:1 ethanol/ethyl ether, deparaffinize the slides through
absolute alcohol, immerse them in the celloidin solution for about a minute,
then transfer them to 80% ethanol for a few minutes to harden the celloidin
film. After that they can be rehydrated and stained as usual. The celloidin
forms a continuous semipermeable membrane over the entire slide and tissue,
which physically holds the section in place during staining. Most dye
molecules can pass through the celloidin membrane and stain the tissue.
Antibody and enzyme molecules are too large to pass through the membrane, so
techniques involving them cannot be done.  Some standard histochemical
procedures will stain the celloidin as well as the tissue, but this is not
usually a problem because during the final dehydration prior to
coverslipping, the xylene will dissolve away the celloidin.  Many years ago
we used this technique particularly for silver stains involving ammonia,
since the ammonia would attack the gelatin we used as a section adhesive,
and cause the sections to fall off the slides.

> ----------
> From: 	histonet-bounces <@t> lists.utsouthwestern.edu on behalf of John
> Baker
> Sent: 	Thursday, October 5, 2006 9:00 AM
> To: 	Histonet
> Subject: 	[Histonet] tissue coming off slides
> 
> Hi All,  A group I work with just came to ask if there was a way of 
> keeping frozen tissue sections from coming off a slide?  It seems there 
> technician used uncoated/regular slides to mount 100's of sections.  
> The tissues were embedded in OCT and cut at 5 microns but of course are 
> sliding off during any staining procedure.  Is there a protocol of any 
> sort to coat the slides after the fact to retain the sections through 
> staining?  I at least suggested they stain flat.  Any suggestions are 
> appreciated.  John
> 
> John A. Baker
> The University of Michigan
> Orthopaedic Research Laboratories
> Histology Unit
> 109 Zina Pitcher Place, 2218 BSRB
> Ann Arbor, MI 48109-2200
> 734-936-1635
> 
> 
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