cleaning the polytron to remove contamination - (Apr/10/2006 )
Ok so I'm a forum virgin since it's my first time posting but here goes:
I'm using a polytron to homogenize tissue to extract genomic DNA. In between samples I rinse the polytron with 1%SDS, 100% Ethanol and DEPC-treated water.
The problem: some of my samples that aren't suppose to contain a marker gene that I transfected into my samples prior to homogenization show the gene when I do PCR.
So, it appears that my cleaning technique isn't working and I'm getting cross-contamination of samples
Any ideas on how to effectively clean the polytron to remove trace tissue and DNA contamination?
the only way to ensure that the polytron is clean is to take the probe apart and clean each part separately. it is time consuming and cumbersome but it is the only way to ensure that you are not carrying any tissue over to the next homogenization.
I tried taking the probe apart but the whole thing (the shaft that contains the probe) just comes off the polytron. The shaft and the probe inside do not separate.
What about irradiating the shaft+probe?
irradiation probably won't work because the contamination is probably bits of tissue trapped in the probe.
the polytron comes with tools to unscrew (reverse thread, i think) the shaft and blade from the housing. if it hasn't been done for a while it may be difficult to open.
you may be able to solubilize the contaminating tissue by soaking in naoh but the best way to clean is to take it apart.