E-Letter responses to:

brevia: G. Reid McDonald, Alan L. Hudson, Susan M. J. Dunn, Haitao You, Glen B. Baker, Randy M. Whittal, Jonathan W. Martin, Amitabh Jha, Dale E. Edmondson, and Andrew Holt Bioactive Contaminants Leach from Disposable Laboratory Plasticware Science 2008; 322: 917 [Abstract] [Full text] [PDF]

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Published E-Letter responses:

When the Contaminants Lead to Exceptional Results

Josep M. Ribó, Joaquim Crusats, Carlos Escudero   (4 March 2009)

Bisphenol A as a Contaminant in Laboratory Plasticware

Rebecca Roberts   (8 December 2008)

When the Contaminants Lead to Exceptional Results 4 March 2009
Josep M. Ribó Department of Organic Chemistry, University of Barcelona, 08028-Barcelona, Catalonia, Spain, Joaquim Crusats, Carlos Escudero Respond to this E-Letter: Re: When the Contaminants Lead to Exceptional Results	We were pleased to see that A. Holt et al.'s Brevia contribution "Bioactive contaminants leach from disposable laboratory plasticware," (7 November 2008, p. 917) could offer interesting "negative" results in a journal of wide circulation. Their contribution, in addition to its far-reaching implications in molecular biology, biochemistry, and medicine, is also relevant in other topics. In this respect, we want to raise attention to the fact that the contaminants commonly found in plastic material (due to the additives needed for molding and extrusion processes) are, in fact, more abundant and common substances than the enzyme inhibitors reported by Holt et al. Owing to their amphiphilic nature, they may also interfere with experiments in the fields of surface, colloidal, and supramolecular chemistry. For example, we have been conducting studies of the self-assembly of amphiphilic water-soluble porphyrins and obtained an interesting regular monolayer upon deposition of a diluted aqueous solution on highly ordered pyrolitic graphite) (1). However, in control experiments we found that the mere contact of water with brand-new disposable polyethylene laboratory material (e.g. screw-capped centrifuge tubes) was enough to produce a solution that yielded the very same monolayer. Following identical procedures as those described by Holt et al., we identified 1-monostearoyl-rac-glycerol, a compound which is extensively used in the molding of organic polymers as a mold-release agent, as the actual monomer in all our experiments (1). The frequency of publication of matching images obtained with different and unrelated compounds raises suspicions about the origin of such monolayers. We think that these findings compel the authors of future papers to give detailed procedures of the precautions undertaken to avoid such contamination, instead of just providing the bare description of the plasticware origin. Joaquim Crusats, Carlos Escudero, and Josep M. Ribó Department of Organic Chemistry, University of Barcelona, Martí i Franquès 1-11, 08028-Barcelona, Catalonia, Spain. Reference 1. C. Escudero et al., Thin Solid Films 515, 5391 (2007).
Bisphenol A as a Contaminant in Laboratory Plasticware 8 December 2008
Rebecca Roberts, Professor Ursinus College, Collegeville, PA 19426, USA Respond to this E-Letter: Re: Bisphenol A as a Contaminant in Laboratory Plasticware	G. R. McDonald et al. recently showed that contaminants can leach from disposable laboratory plasticware and affect bioassay results (Brevia, "Bioactive contaminants leach from disposable laboratory plasticware," 7 November 2008, p. 917). They also drew attention to the recent concerns surrounding bisphenol A, a chemical with estrogenic properties. Researchers should be aware that estrogenic contaminants have been found in labware (1, 2). However, in 2006, we published a study on the leaching of bisphenol A from tissue culture plates from six different manufacturers under typical cell culture conditions and found no detectable leaching during a seven-day incubation period (3). While we all need to be cognizant of possible contaminations, these findings should ease some concern regarding bisphenol A contamination during tissue culture experiments. Rebecca Roberts Ursinus College, Collegeville, PA 19426, USA. 1. A. M. Soto, H. Justicia, J. W. Wray, C. Sonnenschein, Environ. Health Perspec. 92, 167 (1991). 2. T. Ishikawa et al., Nat. Biotechnol. 19, 812 (2001). 3. C. Biswanger, L. Davis, R. A. Roberts, In Vitro Cell Dev. Biol-Animal 42, 294 (2006).