_Patsy's advice is very sensible._  Silanized slides work
on the principle of electrical attraction between the treated
glass (which has amino groups covalently joined by short 
hydrocarbon chains to the glass's silicate ions) and the 
negatively charged groups (especially half sulphate esters 
of certain macromolecular carbohydrates) that occur in the
extracellular matrix of animal tissues. This electrical 
attraction is greatest in the case of tissues that are rich 
in sulphated carbohydrates (such as cartilage), and when 
staining from acidic solutions, which favour the protonation 
of the amino groups of the treated glass slide. 

If you expose a silanized slide to some other adhesive, it
may neutralize or reverse the positive charge. This is not 
necessarily a bad thing, but it wastes the extra money spent 
on buying positively charged slides (or the extra time, if
you make your own, which is very easy and much cheaper). 

Silanized slides may not be the best if you are exposing
sections to alkaline reagents, which strip sections off
slides with greater efficiency than acids. In an alkaline
environment the amino groups of the slide are not protonated
and the surface is not positively charged. For protection
against strongly alkaline reagents chrome-gelatin does a 
better job. It works by a quite different mechanism from
that of a positively charged glass surface.

For a short account of the whys and hows of keeping sections 
stuck to slides, you may like to read
http://publish.uwo.ca/~jkiernan/adhesivs.htm
This little article explains some principles and includes 
practical instructions for three methods. 

If you use a commercial product to enhance adhesion of
sections to slides, you should find out what it is and
how it works. I've never used a trade secret commercial 
section sticker. I have tried a diluted poly(vinyl acetate)
glue, following a published paper 

Harsh reagents do not all work in the same way to detach
sections. I've already mentioned the different adhesive
strategies for resisting acid and alkali, but these are not
the only challenges. For example: if you use a proteolytic 
enzyme such as trypsin to expose epitopes for 
immunohistochemistry, it would not be wise to use a sticky
protein such as egg albumen as an adhesive, even though 
albumen has been used for a century for glueing sections
to slides and is still popular. 

John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/
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Patsy Ruegg wrote:
> 
> I have been told that using charged (silane coated) slide from a water bath
> with any thing other than water in it would negate the charge property.
> Patsy
> 
> -----Original Message-----
> From: Chung, Luong [mailto:lchung@ppmh.org]
> Sent: Thursday, May 22, 2003 11:57 AM
> ...
> Would there be any effect to the charged slide if you place it in the water
> bath with STA-ON solution along with the non-charged one?
> ...
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