Plastic not so fantastic for lab experiments
Worries over a chemical that may seep out of some plastics has caused many consumers to abandon reusable water bottles. Now scientists might want to do the same thing with their test
It seems ingredients in commercial plastic test tubes used by labs around the world can block some biological reactions, potentially leading researchers to bogus conclusions about
whether drugs work or not.
Water alone is enough to leach these chemicals out of plastic tubes, says Andrew Holt, a biochemist at the University of Alberta, whose team noticed the effect while testing
experimental drugs that could potentially treat Parkinson’s disease.
The finding backs up anecdotal evidence from scores of scientists that plastics seem to affect some experiments, Holt says.
«People are clearly aware that plastics can cause problems. Quite remarkably, nobody appears to have done what we were forced to do», he says.
After noticing that his lab’s measurements of an enzyme called MAO-B were all over the chart, Holt and his colleagues set out to identify the cause. The likeliest culprits were plastic
microcentrifuge tubes – the molecular biologist’s equivalent to a mixing bowl.
Water stored in the tubes from several manufacturers was found to block the MAO-B enzyme by as much as 40%, Holt’s team found.
When they analysed the contents of the water they found traces of an antimicrobial compound and a chemical that prevents water from sticking to the plastic – both added intentionally to
the plastic by the manufacturers.
Furthermore, plastic pipette tips – a one-use product that delivers small amounts of liquid for experiments – also leached chemicals that block biological reactions. And chemicals from
plastic plates used in protein experiments actually made the MAO-B enzyme more active.
These effects could distort experiments enough to make a big difference in research. «I think it’s inevitable that a lot of data that’s in the public domain will be skewed in some
way», Holt says, though he hasn’t yet identified papers with erroneous data or conclusions.
«The end result is that researchers are wasting massive amounts of time and massive amounts of money», he adds.
The problem may even extend to sterile plastic containers that researchers use to grow cells, says Simonetta Sipione, who is also at the University of Alberta, though was not involved
in the study.
Sipione studies Huntington’s disease and suspects that leaching from plastics might have caused the mysterious death of cultured brain cells in her lab.
Washing the dishes
When Holt first suspected that plastics were causing problems for his lab, he contacted the manufacturer of his pipette tips, a German company called Sarstedt, who could not replicate
his lab’s data.
Holt says that is because they didn’t perform the experiment as sensitively as his team. «I never heard back from them, and that was more than a year ago», he says.
However, Holt doesn’t hold companies like Sarstedt responsible. Manufacturers add antimicrobial and static-reducing chemicals to make lab-ware more useful for scientists, and it seems
that few if any researchers have alerted companies to problems with their plastics, he says.
For now, Holt’s lab washes suspected plastic immediately before experiments to leach out as many chemicals as possible. But the time-consuming procedure is untenable as a permanent
solution, he says.
Leached chemicals seem to block some proteins, but not others. Holt hopes manufacturers see an opportunity and create plastic wear with a variety of additives, so researchers can pick
the one that’s least likely to mess with their experiments.
«It leaves us in a mess, but I don’t think it’s a mess that we can’t address», he says.