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Biology's McGyver: DIY DNA P.C.R.
joesao writes "In this short, charming interview, Dr. Eva Harris talks about popularizing biology by doing what she calls "knowledge-based" technology transfer: "...people purify DNA for P.C.R. processing with a fancy substance made of silica particles, which costs about $100 for a few milliliters. [...] So what we've done is buy a 20-pound bag of ceramic dust for $5 at the hobby store. And you wash the stuff in nitric acid and sterilize it, and then you have thousands of tubes of that substance. We're not violating anything because the commercial manufacturers have their way of doing this, and we have ours." Open-source biology, anyone?"
But since (amazingly) the process is patented you can't make a buck off it unless you pay some licensing fees. But yes, those that have paid those licensing fees have made RIDICULOUS profits from 16 well cyclers.
It's MacGyver, not McGyver.. how ignorant can you be! :P
Almost every company that sells you some sort of PCR purification / gel purification / miniprep kit that has a spin column or a vac manifold column has some "proprietary formulation" in their columns, but it's silica based. Decrease the pH to about 3.5-4 and your DNA sticks via its phosphodiester backbone. Change it back to 7-8, and the DNA elutes into your TE/H2O/whatever. This is exactly what she is talking about. There were 2 papers published around '83-'84 that describe the use of silica gel for DNA purification. Finding some modification that makes your yield go up and slapping a sticker on it and selling it is big money.
Kids. Back in the day, we'd make our own competant E. coli using the Hanahan method.
In the walk-in -20C.
Uphill.
Both ways.
Silica stuff works great when you do not want to think, or you do not have time for error. Just buy a kit from Qiagen. They use essentially the same columns for dna exctraction from blood, tissue, cells etc. For a relatively low sensitivity simple methods often work great. e.g. for PCR detection of Hepatitis B virus, one can incubate serum with 50 mM NaOH for 30 min at 37C, neutralize and go. But if you need to get a single-copy gene or low titer virus - silica columns or absorption on paper is your best bet.