Every once in awhile a product comes along that just seems to make good sense. I was recently introduced to such a product: The UPrep Universal Spin Filter Column from Genesee Scientific (San Diego, CA and Wake Forest, NC). The idea behind the UPrep column, which is the brainchild of Genesee CEO and co-founder Ken Fry, is that most, if not all, nucleic acid purification or clean-up kits come equipped with 10-15% more reagent volume than is actually needed for the number of columns the kit contains. This means that for a kit with 100 columns, you end up with enough reagent for another 10 to 15 preps after you run out of columns. Normally, this excess reagent is tossed out. However, UPrep columns allow you to use this extra reagent for additional preps. The columns have been designed to work with essentially all commercially available purification kit reagents. Genesee claims that nucleic acid yields are comparable whether you use a column supplied with the kit or a UPrep column.
I recently needed to perform sufficient mini-preps to obtain 20-30 µg of plasmid DNA. I performed 6 preps with a QiaPrep Spin Miniprep kit (Qiagen, Valencia, CA) using the kit-supplied columns for 2 preps and UPrep columns for the other 4 preps. For each prep I used 2 ml of overnight culture of DH10B cells transfected with pOTB7. This plasmid carries a chloramphenicol acetyltransferase gene as a selection marker and, in this particular case, a cDNA insert of around 1,000 bp. I used the same Qiagen protocol and reagent volumes for each prep. The results were actually quite impressive.
Using the kit-supplied columns, I obtained 7.1 and 7.4 µg plasmid with an average 260/280 ratio of 1.96 +/- 0.02. Using the UPrep columns, I obtained 6.6, 7.0, 7.5, and 7.3 µg plasmid with an average 260/280 ratio of 1.91 +/- 0.05. The average plasmid DNA yield for the UPrep column was about 98% of that obtained with the kit-supplied columns (7.1 +/- 0.4 µg per UPrep column vs. 7.25 +/- 0.2 per Qiagen column). The appearance on a 1% agarose gel of 250 ng of plasmid from each prep was identical. I also had the clones sequenced using samples from each prep. The results showed no difference in the quality of the DNA obtained from the kit-supplied column or the UPrep column. Excellent sequence was obtained out to 750 bp and beyond from both preps.
In summary, the UPrep column performed precisely as advertised. Plasmid yields were essentially identical and the 260/280 ratio, appearance on the gel, and sequencing results all suggest a very clean plasmid that is indistinguishable from that isolated using the kit-supplied column. And, at our institutional price of 50 columns for $24.99, they are quite cost-effective. One more thing that bears mentioning is that Genesee plans to come out with a set of universal buffers that can be used for plasmid preps, DNA clean-up, gel purification etc. The reagents will be supplied with appropriate protocols that delineate which buffers to use for any particular prep. With these reagents, all you need are the columns and the reagents to be able to perform a variety of nucleic acid prep and clean-up procedures without having to purchase individual, and expensive, kits.