Use dialysis tube to concentrate virus - (Jul/19/2012 )

Hi, I am trying to use dialysis tube to concentrate my virus. Then today, I used buffer without virus inside the dialysis tube and 10% polyethylene glycol (MW is 35000) solution outside the dialysis tube for the experiment. The cutoff molecular weight of the dialysis tube is 3500. After two hours, I did not notice the decrease of buffer inside the tube. I searched the poster in this website and find one posted in 2006 saying by someone that this method is very fast which may take less than 1 hour. So, I want to ask if somebody know what happened to my experiment. Thank a lot!

What concentration buffer did you use inside and outside?

glycine buffer with pH of 9.5 and 0.3 M NaCl.

Would you notice an less than 10% change in volume?

Yes, it needs time to make the volume reduced. But why somebody ever said that the volume could be reduced super fast. Here is the link: http://www.protocol-online.org/biology-forums/posts/20733.html.

Was it a typo that your MW of PEG was 35,000? I have 3500 and 8000 on my shelf, but not 35,000. If it was really 3500, then your dialysis membrane will be letting it through.

Yes, I am using PEG with MW of 35 000, not 3500 and 8000.

Why not try spin ultrafiltration, i.e. with an Amicon or Spin-X 100KD MWCO filter? Bam, you're done.

Hi Jakester, thank you very much for your suggestions. Could you provide me with more information about the spin ultrafiltration? I do not know where I can get that stuff and how it looks like, as well as how to use it. Thanks again.