NuSieve 3:1 is a high resolution, standard melting temperature agarose (>90C) that can be used for fine resolution of DNA, RNA and PCR products and is excellent for detecting small fragments by either Northern or Southern blotting. Using this agarose we have been able to resolve nucleic acid fragments from ~20-2000bp with either TAE or TBE buffer (using gels from 2%-4%).
I have used the product daily for over a year primarily to run out digested PCR products of human genes to detect polymorphisms. Using this method, we were able to detect a polymorphism that correlated with the progression to AIDS in HIV-infected people (Science 1997 August 15; 277: 959-965). In order to detect this polymorphism we had to be able to observe an 18 bp restriction fragment - I used a 4.5% NuSieve gel to successfully screen about 3800 samples.
According to Lonza, resolution of up to 1 kb can be achieved using the NuSieve 3:1 agarose. However, using 2% concentrations of the agarose, I was able to resolve PCR products of up to 1.5 kb. On the other end of the spectrum, with this agarose I have used concentrations of up to 4.5% and was able to resolve PCR products as small as 15-20 bp. The company claims resolution of 30 bp, but in order to see this or smaller pieces of DNA, one may have to load more DNA on a gel than comes from a standard PCR reaction. However, very little ethidium bromide is required to visualize DNA fragments. This agarose can be prepared with an autoclave, hot plate or microwave (I have used some agaroses that when heated in a microwave boil over).
NuSieve 3:1 is a little more expensive than standard grade agarose, but it is well worth the price if high resolution is needed. One thing to keep in mind is that at 3-4% concentrations the gel is very strong but at concentrations below 3% the gel becomes fragile and must be handled carefully.
All in all, I would definitely recommend this NuSieve 3:1 to anyone who requires resolution of nucleic acids in the 20-2000 bp range. For separation of nucleic acid fragments in this range I am not aware of a better agarose.
Keith Byrd
Graduate Student
Johns Hopkins University