Stronger acrylamide gel.

TFitzwater at Gilead.com TFitzwater at Gilead.com
Wed May 23 14:31:53 EST 2001


>Zhongtang Yu (zyu at interchange.ubc.ca)
>Tue 22 May 2001 - 15:01:15 BST


>Is there any commercial acrylamide with which a stronger gel can be
>made? I used the Duocryl, but at 3.5% concentration, Duocryl gel is
>still very
>fragile. ExplorER Gel Solution from J. T. Baker is claimed to form
>stronger
>gel. Does any one have use it? Your info is very much appreciated.


>--
>Zhongtang Yu, Ph.D.

I'm not sure what you mean by "stronger."  The ratio of TEMED to acrylamide
plays an important role in determining how strong or brittle an acrylamide
gel will be.  Use of more than the recommended volume of TEMED will result
in brittle gels.  The properties of the gel depend on the concentrations of
APS and TEMED.  Increasing the amount of APS/TEMED leads to an increase in
chain initiation events and a corresponding decrease in chain length,
resulting in gel turbidity and decreased gel elasticity.  I decrease the
amount of TEMED according to the concentration as indicated (a/b/c, where a
= % acrylamide, b = uL TEMED for 100 mL of degassed denaturing gel, and c
= uL TEMED for 100 mL of native gel): 4/24/22, 6/22/20, 8/20/18, 10/18/16,
12/16/14, 14/14/12, 15/13/11, 16/12/10, 18/9.5/7.5, and 20/7/5.  The TEMED
volumes have been adjusted to allow consistent polymerization times
regardless of the acrylamide concentration.  This compensation prevents the
brittleness common in high percentage gels by using less initiator in order
to generate longer polymer chains.  20% gels remain flexible.  You might
try similar modifications with Duocryl.

Tim Fitzwater
Associate Scientist
Gilead Sciences


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