Apparently there is a belief that contaminated steam in the autoclave can contaminate your pipette tips while sterilizing them with biomolecules such as peptides and DNA, and that this can be a problem for false positives in PCRs. I have been searching around but can't find any research on steam transport of biomolecules, does anyone know any papers about the fundamental science behind this - if this is actually true?
Article The time required for water attack at the phosphorus atom of...
the hydrolysis half life of DNA makes destruction in a 30min 221C autoclave cycle look highly unlikely. Heck the PCR reaction is near boiling as well.
The destruction of DNA under autoclave I think it is quite poor, there are a few papers about that. What I am wondering is if DNA from the autoclave water could end up being transported in the pressured steam to the samples while autoclaving, potentially coating them with biomolecules when autoclaving a clean sample. Some people use foil around their pipette boxes to avoid this water to wetting the samples and potentially contaminating them with stuff from the water, but I am trying to understand if this is even possible. Edward Michelini
Modeling steam or water droplet flow in a rapidly heating/cooling autoclave would tax a serious computer, so real world testing would be the obvious choice. I could envision a regimented sampling pattern over the surface and internal to the autoclaved container with qPCR scoring after spiking the base water or a single container with a template oligo. While I can't envision an aerosol dispersal of DNA template in live steam it very likely happens, similar to pipette tip contamination at room temp. First I'd like to know how the result could inform "best practices"? A DNA purge cycle with a thermolabile DNAse might be required but these enzymes make molecular biologists very nervous, with good reason. Where might a positive (or negative) result lead?
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