"Frank O. Fackelmayer" <Frank.Fackelmayer at uni-konstanz.de> wrote in message
news:38673251.A82DDEA5 at uni-konstanz.de...
> "Ian A. York" wrote:
>> > In article <386117C6.C6D8C7F3 at uni-konstanz.de>,
> > Frank O. Fackelmayer <Frank.Fackelmayer at uni-konstanz.de> wrote:
> > >
> > >1. Prepare a 25% solution of waterfree PEI (Aldrich cat. No 40,872-7)
> > >water. Waterfree PEI is extremely viscous (cannot be pipetted), so we
> > Thanks from me as well for posting this, Frank. We're definitely going
> > give this atry.
> > How would you store the 25% solution once you've made it up? 4 degrees
> > -20 degrees, room temp?
> > Ian
> > --
> > Ian York (iayork at panix.com) <http://www.panix.com/~iayork/>
> > "-but as he was a York, I am rather inclined to suppose him a
> > very respectable Man." -Jane Austen, The History of England
>> Hi Ian,
> Well, I haven´t thought about long-term storage yet. I think the material
> itself should be stable, but I really don´t know if microbial
> will be a problem. As I haven´t neutralized the 25% stock (which has a pH
> between 11 and 12), I hope that nothing will grow in it... But, of course,
> we´ll have to do some storage experiments to see if transfection
> drops over time.
>>Even if neutralized, their is no microbial contamination due to the excess
in charges confered by PEI. Store for up to six months and no contamination
even if used under non sterile conditions.