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Published online 6 November 2008 | Nature | doi:10.1038/news.2008.1212
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Why plastic isn't always fantastic
Experiment-ruining chemicals leach from plastic lab equipment.
Thousands of scientists could be unwittingly ruining their own experiments merely by using standard plastic lab equipment, according to a new study.
Andrew Holt, a researcher at the University of Alberta in Edmonton, Canada, was looking at how drugs affected the human enzyme monoamine oxidase B when he noticed that the drugs seemed to be inhibiting enzyme activity at much lower concentrations than they should.
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Eppendorf's statement seems somewhat cryptic to me. What does "not experienced any product problems with our customers due to the substances mentioned" actually mean? They did not experience any problems (with chemicals or with customers)? The customers neither? Or only the customers? Were there problems reported, but concerning other substances than those mentioned in the article? Furthermore, the presence and nature of the found chemicals should be no mystery to the manufacturers. It seems to me that these are employed knowingly in the manufacturing process, and in my opinion the manufacturer should ensure & guarantee that his products are free from these contaminants.
oopsss...if this is really happening...Is it possible that the past researches utilizing plastics stuffs that has been published would have some errors?..mmmm..
Allowing for some poetic license, does unnoticed Chaos Theory find a place in our pristine science laboratories?
I totally agree with the article. All people working on cell cultures know that plastic is ( not only toxic) but also can modify the effect of molecules. This is absolutely iumportant in toxicity test by using clonogenic tests as GM-CFU assay et al.... ( A Pessina et al.,Toxicological Science, 75,355.2003)
The concern is not only appropriate when working with biomaterials. Leaking of additives from plastics is as well worth a thought when doing chemistry in general. Whenever a chemical (including water) gets into contact with plastics it may become contaminated. Additionally the chemical of interest may diffuse into the plastics and may contaminate another chemical when the plastic device is used a second time. By the way, the smooth moving of the piston in a syringe is due to a lubricant which gets dissolved in organic solvents.
We had this very problem in our own lab, when chemicals leaching from plastic tubes increased the UV absorbance of our samples, and confounding nucleic acid quantitation. Even very simple assays can be significantly impacted by these effects.
Most chemistry trained professionals in research know that plastics induce changes in biochemical reactions. Meticulous enzymology related biophysical work involving NMR, EPR, spectroscopy, titration calorimetry, rapid kinetics, etc are always done using glass apparatus (not all techniques are listed). However, in cell and molecular biology and tissue culture labs the use of sterile, disposable plastic is inevitable. The results obtained with microscopic quantities of protein and DNA, that is inherent to small-scale work, would be further complicated by leaching of plastics. This would have lead to many unlikely and non-repeatable results ever so often; attrition rate in experiments is very high!! But a typical lab carries in its inventory only sterile, disposable, plastic items. Alas, "this is what we have in our labs"!! Is there a reasonable solution?
A second comment to my first. On a yacht race a beverage cooler was filled with small water bottles and iced down for a 125 mile event. On the second day when the ice had mostly melted the water inside the plastic water bottles tasted of gasoline. It was then recalled that the cooler had a year earlier been used to capture some gasoline spillage. It had been scrubbed and bleach was used as well. But by the taste test, the gasoline chemistry had entered the cooler liner, then a year later migrated out and through the water and into the contents of the sealed water bottles. We're doomed?
I have conducted organic solvent extracts on hundreds of plastic and elastomer samples over the last 12 years as part of my work assessing the toxicological risks associated with permanent implantable medical devices. Low molecular weight leachable compounds are present in nearly all plastics with wide variation in quantity and character of the leachables in supposedly identical materials. Not only are there differences in monomer and polymer resin compounds but exposure of plastics to other compounds from processing, packaging, handling and storage can make a profound difference in the leachable profiles. Cleaning with organic solvents prior to use can reduce the potential adulterants but you may then have to worry about the residual cleaning agents. Impervious material such as glass and metals reduce the risk of contaminants that may permeate into the surfaces but surface contamination of impervious materials may still be a problem.
This scenario brings back the little saying made years ago....."Nothing stands between you and the flavor when it's bottled in glass, no return glass!" Soarhead
Ana Soto and Carlos Sonnenschein over a decade ago found that nonylphenol was leaching from plastic lab ware affecting their breast cancer cells assays (Soto, et al., Environ. Health Perspect., 92:167-73, May 1991). It doesn't surprise me that there are other chemicals leaching from the plastic that will affect ones assays. It would be interesting to know whether the same chemicals are leaching from plastics used in every-day plastic ware (such as water bottles etc.), and what their potential adverse health effects might be.
I have had similar experiences in my experiments. I was once using plastic petri dishes for holding a Calcium Silicate Hydrate compact immersed in the Lithium Nitrate solution. After elemental surface analysis on the samples (to investigate possible chemical degradation due to the solution) I found aluminum! It had been dissolved from the container. Al is apparently used in the form of aluminum oxide to increase the stiffness of the plastic. In my case Al is very critical as it can substitute Si in the C-S-H structure.
For those of us that work in cell culture, this poses quite a problem. Most culture medium and supplements, including serum come in plastic containers so potential contaminants are there from the start and no amount of precleaning plastic tips, flasks or microplates would appear useful. What is the recourse?
Whoever had the chance to work with sensitive cell lines such as truly normal cells or primary cultures knows that there are GOOD and BAD or VERY BAD plastics out there.... Or, rely on your taste buds for example and compare the quality of the drinking water in some of the bottles being sold here and there. BTW, glass is probably not much better. Who knows what is leaking out of this amorphous liquid or solid however one wants to call it!
We followed this up with another story in December. See http://www.nature.com/news/2008/081209/full/news.2008.1291.html There's also a Nature opinion forum on plastics here http://network.nature.com/groups/naturenewsandopinion/forum/topics/3990