Autoclaving flask stoppers: rubber, silicone, or something else?
July 7, 2011 2:20 PM Subscribe
What is the best flask stopper material for repeated autoclaving / use in sterile applications? Is rubber okay? Would silicone (or something else) be better?
[lab monkey filter]: A researcher colleague here (small biotech facility) is looking to construct a system in which certain parts must be sterile. Glass flasks and bottles are no problem, as I know those can be autoclaved. But what about the flask stoppers?
My instinct is that repeatedly autoclaving *rubber* stoppers (the only kind we have right now -- they're black and smell like car tires) would result in them cracking (making lovely sites for bacteria to burrow into) and just plain falling apart faster than they otherwise would.
They're the type with a single hole down the middle, mind you, so I am not really worried about corked bottles exploding in the autoclave -- mainly I am thinking of material fatigue and/or exposing Important Experiments(TM) to needless contamination risk.
Anyway, thus far the googles inform me that flask stoppers are actually available in a variety of materials. Presently silicone seems like our best bet, but is there something potentially even better?
Moreover, is there any empirical data out there to support my suspicion that rubber stoppers should NOT be repeatedly autoclaved (or, conversely, that my concern here is in fact baseless)?
[lab monkey filter]: A researcher colleague here (small biotech facility) is looking to construct a system in which certain parts must be sterile. Glass flasks and bottles are no problem, as I know those can be autoclaved. But what about the flask stoppers?
My instinct is that repeatedly autoclaving *rubber* stoppers (the only kind we have right now -- they're black and smell like car tires) would result in them cracking (making lovely sites for bacteria to burrow into) and just plain falling apart faster than they otherwise would.
They're the type with a single hole down the middle, mind you, so I am not really worried about corked bottles exploding in the autoclave -- mainly I am thinking of material fatigue and/or exposing Important Experiments(TM) to needless contamination risk.
Anyway, thus far the googles inform me that flask stoppers are actually available in a variety of materials. Presently silicone seems like our best bet, but is there something potentially even better?
Moreover, is there any empirical data out there to support my suspicion that rubber stoppers should NOT be repeatedly autoclaved (or, conversely, that my concern here is in fact baseless)?
Response by poster: aganders3: Oh, cool, the ground glass joints look like a definite possibility. The only thing I am not sure about is whether there are any that would work with our existing flasks, or whether we would need to buy additional glassware to go along with them. That wouldn't necessarily be a bad thing, I just need to research a bit.
posted by aecorwin at 2:56 PM on July 7, 2011
posted by aecorwin at 2:56 PM on July 7, 2011
I have distinctly seen glass flask stoppers in the lab I work with. They go into and out of the autoclaving unit all the time. I have no idea about price, since I work with the toy testing division. A second idea, which might get expensive over time, is to buy sterilized rubber units and treat them as a single use item. My inner cheapskate hates that idea, but I have lots of items that are used only one time for testing because that's what is required.
posted by Nackt at 6:08 PM on July 7, 2011
posted by Nackt at 6:08 PM on July 7, 2011
Best answer: Here are some autoclavable Teflon stoppers. That's what I'd use. Ground glass joints occasionally freeze up unless you lube them with silicone grease but that can introduce contaminants (and silicone grease is a bitch to wash off). Both of these are hard to make holes in, though.
If you have to stick with either rubber or silicone for the sake of the holes, I'd pick silicone. Silicone is heat-resistant and reasonably chemically inert. Rubber disintegrates pretty quickly in comparison.
posted by Quietgal at 8:43 PM on July 7, 2011 [1 favorite]
If you have to stick with either rubber or silicone for the sake of the holes, I'd pick silicone. Silicone is heat-resistant and reasonably chemically inert. Rubber disintegrates pretty quickly in comparison.
posted by Quietgal at 8:43 PM on July 7, 2011 [1 favorite]
Response by poster: Okay, wow, thanks, folks! Ground glass joints may work well for some of our applications, but for this project I am thinking our best bet is teflon or silicone. Wonderful to know that such things exist!
posted by aecorwin at 1:34 PM on July 12, 2011
posted by aecorwin at 1:34 PM on July 12, 2011
This thread is closed to new comments.
posted by aganders3 at 2:37 PM on July 7, 2011