Lower temperature methyl cellulose
July 25, 2016 7:38 AM Subscribe
Methyl cellulose solution has the handy property of being liquid up to about 50deg C, and becomes solid(ish) above that temperature. I'm looking for a substance that does the same, but with a transition temperature somewhere around 0-20deg C.
Bonus points for being water-based and fairly non-toxic. I have access to decent lab chemical suppliers.
Bonus points for being water-based and fairly non-toxic. I have access to decent lab chemical suppliers.
sorry, this is so obvious it's likely useless, but water/ice seems to meet your reqs.
posted by andrewcooke at 8:03 AM on July 25, 2016
posted by andrewcooke at 8:03 AM on July 25, 2016
I think metaBugs is looking for something that transitions from liquid to solid as the temperature increases - in other words, water/ice would work if heating water turned it to ice.
From wikipedia: At temperatures below the LCST, it [methyl celluslose] is readily soluble in water; above the LCST, it is not soluble, which has a paradoxical effect that heating a saturated solution of methyl cellulose will turn it solid, because methyl cellulose will precipitate out.
posted by neilbert at 8:08 AM on July 25, 2016 [1 favorite]
From wikipedia: At temperatures below the LCST, it [methyl celluslose] is readily soluble in water; above the LCST, it is not soluble, which has a paradoxical effect that heating a saturated solution of methyl cellulose will turn it solid, because methyl cellulose will precipitate out.
posted by neilbert at 8:08 AM on July 25, 2016 [1 favorite]
Best answer: Matrigel polymerises around twenty degrees although I don't remember the exact temp. My experience is that everything has to be ice cold (including pre-cooled pipette tips) or it will solidify on you, so there's that. Different extra cellular matrices (eg gelatin, fibrinogen) may gel at a lower temp, and they're all water soluble and non toxic.
posted by shelleycat at 8:10 AM on July 25, 2016 [2 favorites]
posted by shelleycat at 8:10 AM on July 25, 2016 [2 favorites]
Best answer: Geltrex supposedly gels at 15 degrees, which sounds about right based on my experience. All these products are expensive, but maybe polymerisation in general is a useful place to look?
posted by shelleycat at 8:14 AM on July 25, 2016 [1 favorite]
posted by shelleycat at 8:14 AM on July 25, 2016 [1 favorite]
oh, sorry.
posted by andrewcooke at 8:15 AM on July 25, 2016
posted by andrewcooke at 8:15 AM on July 25, 2016
Response by poster: Ah, geltrex and matrigel might be good actually. I need to be able to "melt" the substance again after it has solidified -- as methyl cellulose will melt when the temperature drops below 50 degrees -- but i only need to do it once, so a fairly mild MMP digestion might do the trick.
...this is for holding biological samples in place for microscopy without squashing, slicing, heat shocking or otherwise mangling them, and being able to keep them growing afterwards. I only think of matrigel as a matrix for tissue culture, it'd never have occurred to me for this. Thanks!
posted by metaBugs at 9:07 AM on July 25, 2016 [1 favorite]
...this is for holding biological samples in place for microscopy without squashing, slicing, heat shocking or otherwise mangling them, and being able to keep them growing afterwards. I only think of matrigel as a matrix for tissue culture, it'd never have occurred to me for this. Thanks!
posted by metaBugs at 9:07 AM on July 25, 2016 [1 favorite]
I have used matrigel for growing cells for microscopy (3D cell migration studies) so it's totally compatible with that. There should be protocols for getting them back out again because I know it's done, maybe look at organoid protocols for ideas.
posted by shelleycat at 10:10 AM on July 25, 2016
posted by shelleycat at 10:10 AM on July 25, 2016
...this is for holding biological samples in place for microscopy without squashing, slicing, heat shocking or otherwise mangling them, and being able to keep them growing afterwards. I only think of matrigel as a matrix for tissue culture, it'd never have occurred to me for this. Thanks!
There's low temp agarose too, thought it sounds like that's probably too hot for you.
posted by maryr at 10:22 AM on July 25, 2016 [1 favorite]
There's low temp agarose too, thought it sounds like that's probably too hot for you.
posted by maryr at 10:22 AM on July 25, 2016 [1 favorite]
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If you want that big transition range then dissolving something in it will lower it and make the freezing event a range. Even 2-3% water would have a big effect.
posted by mark k at 7:50 AM on July 25, 2016