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hot start beads

Benny Shomer bshomer at ebi.ac.uk
Thu Dec 28 18:54:59 EST 1995

: Netters,
: We have used Invitrogen's HotStart Beads with wonderful results
: but they are VERY EXPENSIVE.  Cost is a major concern to us
: because we run LOTS of PCR reactions.  At the lowest cost we
: can purchase Invitrogen's beads (20,000+) it would still cost
: over $41 per 96 PCR reactions for the beads ALONE!!

: We are testing the use of paraffin wax (Aldrich) and mineral
: oil (used as a softener of the wax following the mixing of the
: limiting reagent and the reaction mixture) but have yet to hit
: upon a combination that we are happy with.  This approach
: requires a fair number of pipetting steps but the cost would be
: low.

I posted this some two-three years ago. I didn't try to find it in the 
archives, so here it is again.

I used to make  paraffin wax beads in the following method:

Prepare a wide container with ice-cold DDW. (A 2 liter beaker flask
is pretty nice, but any other will do).

You need a convinient household type mesh (the round rigid ones), small 
enough to fit in the beaker.

Melt the parafin and use a wide end pipete to apply the parafin on the 
water's surface dropwise. I used at the time a 25ml pipete. It takes 
some training to obtain the appropriate size of bead.

The beads float to the beaker's edges, so more drops can be added until
there's no more space. Collect the beads with the mesh and dry.

Keep the water in the beaker ice-cold.

I never added magnesium to the beads and I never had any problems with
my PCR's.

I hope this helps. Good luck,

Doing PCR?
Have you got some good, working primers???
Visit the PCR primers database at http://www.ebi.ac.uk/primers_home.html
and make your donation.

If you don't have access to WWW, just write to primers at ebi.ac.uk

Benny Shomer
External Biological Liaison Officer,
EMBL outstation - The EBI,
Hinxton Hall, Hinxton,Cambridge CB10 1RQ, UK

Tel:   +44-223-494437
Fax:   +44-223-494468
Email: bshomer at EBI.ac.uk


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