I am looking for a gel which can be stored at temperatures ranging
from freezing to 130 F. with a minimum shelf life of 6 months. We used
agar, which performed well, however, the problem is that the Agar
shrinks after just a few days. Does anyone have suggestions for a
substitute for the agar gel?

Thanks,

Mark

Gregg,

It is used to demonstrate a device. The colored agar is put in a sealed
clear
tube together with water. The device spins and breaks up the agar into
smaller
and smaller pieces. The goal is to see the pieces spin around and get
smaller
until they dissolve into the fluid. The agar must be a soft gel for the
demonstration to work. A 0.08% ratio of water/agar seems to work best. Can
you
think of way to make the gel more brittle?

The translucency is not important. The gel should be non-toxic and
inexpensive.
I tried propylene glycol just a few days ago. It prevents the solution
from
freezing and appears to reduce the water loss. I am hoping that it will
prevent
the agar from drying out and also will eliminate the need for the use of a
preservative to be added to the gel. Can you think of way to speed up the
life
cycle testing. Perhaps placing the tubes in a warm over (115 F) for a few
days?

I have played a little with xanthan gum/locust bean gels. They do not seem
to
hold up well at temperatures above around 120F.

I have not tried aliginates gelled with calcium salts. I am not familiar
with
these gels (My background is not in life sciences).

Thanks.

Mark

My background is ceramic engineering - I've had the opportunity to use a