building the $100 thermocycler

Dr. Duncan Clark Duncan at nospam.demon.co.uk
Mon Feb 7 06:02:32 EST 2000


In article <FB599DB5ACE2D211887500A0C9D334E44D8774 at TBACRMEXH001>,
Weining, Song <WeininS at prose.dpi.qld.gov.au> writes
>Anybody knows the cost for a Peltier block? I only heard of one supplier-so
>it may not be cheap. We may also need heat pump some sort, cheap stuff in
>the computer industry?       and don't forget, a FAN. $100 would not go very
>far.

The idea of the one published in Analytical Biochem some years ago was
to use heater cartridges for heating and peltier for cooling. One of
course has to get an aluminium block milled precisely for the tube
shape. 2 Peltier elements will use up the USD100. The other problem is
that standard peltiers were abandoned by the machine manufacturers
because they couldn't take the thermal shock of cycling. Now that may
have been because they were initially being used both for heating and
cooling. 

Of course the other way and even simpler is to use a halogen lamp to
heat a lightweight block and just use air to coll. This was one of the
first PCR machines produced and eventually sold by I think Hybaid. It
used to work very well.

Duncan

PS I've searched for the instructions for the home-made machine but I
suspect we've thrown them out. If you can find the Anal. Biochem. paper
then it is worth approaching the authors etc.  
-- 
The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Duncan Clark
DNAmp Ltd.
Tel: +44(0)1252376288
FAX: +44(0)8701640382
http://www.dnamp.com
http://www.genesys.demon.co.uk




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