Scanning densitometry problem

WSchick at WSchick at
Thu Feb 22 09:32:48 EST 1996

In a message dated 96-02-22 00:23:16 EST, daj at writes:

>Hi all,
>we are trying to do scanning densitometry on polyacrylamide gels that have 
>been dried down onto "GelBond" plastic sheets and are getting horrible 
>newton's ring effects between the gelbond and the glass support plate of 
>the scanner 

You might try the cellophane sheets from Pharmacia/Hoefer.  Sandwich the PA
gel between the wet sheets and dry in the Hoefer holders, either in a hood or
in their air driven gel dryer.  The curl comes from shrinkage of the PA gel.
 By putting two cellophane sheets on each side, the gel tension is even and
relatively flat.  I think the cellophane shrinks a little too.   Agarose
isn't corsslinked like PA, so drying doesn't produce the shrinking effect.

We were able to scan PA gels this way on a light beam densitometer--but a
laser may still find some imperfections in the cellophane.

Do yoy have a CCD camer gel documentation system anywhere near you?  This may
be able to eliminate the rings.

Walt Schick

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