A new research reveals that polypropylene tubes can contaminate solutions in the PCR and distort the DNA spectrometer readings.

One year ago, a group of researchers at Hadassah-Hebrew University Medical Center in Jerusalem reported a sharp rise in the diagnoses of a certain metabolic disorder. To those of us who live in Jerusalem, fear not. Other than the Holyland story, nothing really happened in the Israeli capital in the last year. The only change is that the lab at Hadassah changed the supplier of its pipette tips. No more, no less.

You might find it hard to believe that the mere changing of a plastic supplier can affect the diagnosis of a medical disorder. It turns out more and more, though, that plastics can seriously influence the outcome of biomedical experiments and tests.  The most recent example was published just two days ago in BioTechniques by Lewis et al, and caught attention from Nature’s news crew who began circulating the announcement to the scientific community around the globe. It’s might important, too, as the discovery relates to protein and DNA extraction and PCR reactions, which most of the biologists do at one point or another in the research.

To sum up the results briefly, Lewis et al bring evidence that chemicals can leach out of polypropylene tubes and into the solution inside. Those chemicals absorb at wavelengths between 220 and 260 nanometers, which means they’re highly likely to distort a spectrometer reading of the amount of DNA in the solution, perhaps by as much as 300%, according to the researchers.

How to get over the problem? Lewis et al report they are using only tubes which are low in additives. This is another potential problem, obviously, since some of the additives are there for a reason: to harden the plastic, make it more heat resistant or preserving it over time. But if your research is truly important to you, I’d say it’s the right choice.

In the BioMed-ILSI week (two months from now), Prof. Daniel Cohn from the Casali Institute of Applied Chemistry in the Hebrew University will give a lecture on June 15th about Novel Biomedical Polymers and Medical Devices. It might be interesting to learn his views about this problem, and what’s more, perhaps he has an insight on the additives in question – and whether they can be found in implantable polymers as well.

The Incident in Hadassah

BioTechniques Journal

A News Article in Nature on the Matter

The Program of ILSI-BioMed week

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