I'm making experiments with chitosan particles to capture DNA. I have read that in an acidic medium chitosan is in it's protonate state so the interaction between the DNA and the chitosan it's better,
I wanna know in which buffer I can do this reaction to ensure a better interacion between DNA and chitosan (pH between 1 and 4)
Thanks!
Hi there,
Chitosan amine pKa is around 6.5 so you don't need to go very acidic to get chitosan fully protonated. pH 5 should be enough. In this paper, they use actate buffer at pH5.5:
http://www.ncbi.nlm.nih.gov/pubmed/15585274
Hi Alejandra,
I think Dr. Liger's suggestion is completely fruitful. However if you want to go for lower pH than you can use 1N HCl.
Best of luck.
-
Nilesh
Hi Alejandra,
As has already been mentioned, you probably don't need to go to so low pH values to ensure that the chitosan is protonated. However, if you still want to do so, a good rule of thumb is that you should stick within 1 pH unit of the pKa value for your buffer molecule. This gives you some options for pH 1-4, for instance phosphate (pKa 2.15), formate (3.75) and acetate (4.76). Personally, I like to use the following page for buffer guidelines:
http://www.bioinformatics.org/jambw/5/4/index.html
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