Hot Start Wax Beads

brett brett at BORCIM.WUSTL.EDU
Thu Feb 19 13:54:15 EST 1998


>bbeitzel at biomail.ucsd.edu wrote:
>> 
>> Howdy,
>> 
>> Anyone know of a cheap supplier of the wax beads used for hot start PCR?
>> I checked with Perkin-Elmer, and they are charging $100 for 200 wax beads
>> - seems outrageous to me, but I thought I'd check around.
>> 
>> Thanks for any info,
>> 
>> Brett Beitzel
>> bbeitzel at biomail.ucsd.edu
>
>Promega is selling 100 beads for $75.  These beads, however, contain the
>Taq, not the Mg++.  We've used them on a number of reactions, and they
>work well.  They don't make a vapor barrier on a 0.2 ml tube, 100 ul
>rxn, so if that's important, you're out of luck.  They do make a nice
>doughnut-shape that makes rxn removal really easy, which I think is a
>good feature (we have a heated lid on our machine).  My reactions were
>clean, but I didn't have any trouble before I tried these beads. 
>Overall, I've been pleased with the performance.
>
>rich (no affiliation with Promega, etc, just a consumer)

A few years back this topic came up and people suggested making your own
using paraffin.  I bought some "Ameraffin LP" tissue embedding medium from
Baxter (cat M7347-1), melted a bit and spotted 15ul aliquots onto a smooth
surface to harden.  My recollection is we bought 20 *pounds* of the stuff
for around $40-50 bucks, which is at least several thousand-fold cheaper
"real" beads.  Not only did they work fine for PCR, they actually
improved the yields compared to PE's wax beads!!! My guess is there might
be some residual solvent such as DMSO which affects the reaction, but have
not really persued this for two reasons: 1) there was never any problem with
these beads, and 2) we bought a PE9600 and I no longer use overlays of any
kind. Anyways, hope this helps.
Brett Lindenbach
brett at borcim.wustl.edu

Dept Molecular Microbiology
Washington University School of Medicine
Box 8230
660 S. Euclid Ave
St Louis, MO 63110




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