LBNL Seeks Licensees for Highly Specific and Sensitive DNA Extraction Method

Lawrence Berkeley National Laboratory has made available for licensing a DNA extraction and isolation method that its inventors claim is more efficient, sensitive, and selective than current commercial DNA extraction kits.

In particular, the new technique may be especially valuable for downstream applications where the extraction of minute amounts of DNA plays a critical role, such as basic and applied biology research, forensics, biosecurity, and environmental testing, according to the technology's inventors.

"This is a general method to get DNA out from any kind of sample, but with higher sensitivity, we think, than current methods, and more versatility in terms of product models," Youn-Hi Woo, a staff scientist at Berkeley Lab and one of the method's inventors, told PCR Insider this week.

"It has a very broad field of use anywhere someone wants a very small amount of specific DNA from larger samples or a larger pool," she added.

According to the LBNL researchers, the most popular current commercial DNA extraction methods use detergents, paramagnetic particles, or membrane filters. Each of these methods works well for certain applications, but each also has drawbacks, such as non-specific DNA separation and contamination with salts or negatively charged polymers. In almost all cases, the various methods require that researchers perform extra time-consuming or laborious wash steps.

Furthermore, although paramagnetic particles eliminate many of the chemistry-related problems, they are difficult to employ using large sample volumes, meaning that researchers must first concentrate a sample down to microliter-scale volumes or less. This is particularly daunting with the larger-volume samples commonly found in environmental testing or forensics.

The new DNA extraction protocol, which the LBNL researchers described in a paper published earlier this year in Analytical Biochemistry, relies on the combination of the DNA-specific enzyme methyltransferase, or DNA Mtase, and so-called "click" chemistry, which has the ability to irreversibly couple two molecules under mild conditions.

More specifically, DNA in a complex sample is selectively labeled using MTaqI, an Mtase derived from Thermus aquaticus, and with alkynyl-SAM, a cofactor molecule that supplies methyl groups that the MTaqI transfers to the DNA when it recognizes short nucleotide sequences.

Then, the mixture is applied to an azide-modified click chemistry surface in the presence of copper ions, where the selected DNA molecules become covalently bound. Standard or vigorous washing steps wash away any contaminants, leaving behind only the desired DNA molecules bound to the modified surface.

"One strength of this technology is pulling out DNA by covalent bonds," Woo said. "This means it can't be pulled off easily. You can be pretty harsh in the washing steps to get rid of whatever the DNA was contaminated with. This gives you [more] freedom in what you do to purify your sample."

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LBNL Seeks Licensees for Highly Specific and Sensitive DNA Extraction Method