Combining gel filtration and electrophoresis

[Daniel Käsmayr]

>> Is there a way to combine gel filtration with electrophoresis - i.e.
>> separating proteins by size but inverse to that of a general SDS- 
>> PAGE?

> Also not sure I understand the question but if it helps there are
> electrophoresis systems which enable elution of proteins for
> purification etc.  BioRad sell a system with a cylinder of gel  
> which is
> connected to a fraction collector.

What I would like to have is a system that uses electric charge to  
drive particles, but also a matrix that retards smaller particles  
much more than larger ones; resulting in something like an inverse- 
PAGE, where larger particles migrate faster than smaller ones.

The substances that need to be characterized are star polymers /  
brush polymers that have multiple functional groups (amine or  
carboxylic acids) which are used to create peptide bonds to make  
conjugates with DNA and/or Proteins.

What would also help is some sort of modification I could do to PAGE  
that would help me get my star-shaped polymers (and their conjugates  
with proteins or DNA) into the gel. Right now it seems like I either  
do not get them to penetrate the gel matrix (I see only some residues  
on the gel pocket's outside and just a few mm inside the gel - these  
are 3% gels already and ver un-handlable) or they are not stainable  
with a silver stain…
 From my syntheses I know the polymers can be analyzed by GPC/SEC -  
but I don't have enough material for this anymore - DNA is very  
expensive if you are talking about mg amounts.

Dan