We are looking to cut microorganism contamination in our experiments, which involve leaving charged glass samples in buffers/water overnight. Our buffers are usually PBS and MES. I am looking for a reliable way to cut down on microorganisms growth; ideally for storage of a period of a few months.
So far, here's the best protocol I could come up with:
- Autoclave fresh distilled water in a clean bottle.
- Create PBS/MES buffers from this water
- Dilute into 50mL centrifuge tubes.
- Freeze at -20C
If filters are affordable, I thought we could filter the buffers/water after thawing at run time. Are there any issues with freezing buffers in a plastic tube that I might not be aware of? I know freezing can cause some extra gas dissolution, and what about leaching of plastics? For our intents and purposes, these are not a big deal at the moment.
I'm no biologist, so any other suggestions would help big time.
Thanks.
Autoclave the buffer, not just the water. Add 0.01% sodium azide to stop any growth. (Clearly label buffers containing azide, its not only the bugs that find it toxic!)
We also used to add thymol to water tanks etc.
Thanks for the links! We are going to avoid the sodium azide because it introduces amines that are bad for our covalent immobilization goals. I'll just try to filter copiously, especially at runtime.
Dear Adam,
Consider autoclaving the buffers inside the bottle (basics for autoclave, half fill the bottles). You can store the buffers for months if you do not open them. So, make aliquotes good for up to a week.
Thank you.
We've decided on the following protocol, all things considered.
Autoclave and store buffers in autoclaved bottles.
At use time, run them through dedicated sterile filters. We have a filter for each bottle, which when not in use, we leave in a desicatted bag in the fridge. We hope to get at least 5 uses out of each filter before replacing.
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology
- Microorganisms