Nucleic acid decontamination 

Anyone working in genomics, PCR laboratories or molecular biology is familiar with the challenge of DNA contamination: nucleic acid molecules can quickly contaminate a PCR sample and lead to false-positive results. It is almost impossible to reduce or remove these artifacts once they have occurred.  
Nucleic acid molecules are found practically everywhere in the environment - for example as aerosols - and have proven to be exceptionally stable: researchers in Greenland were recently able to detect two-million-year-old animal DNA fragments.

 
When autoclaving is not enough

The autoclaving process is usually used in laboratories to sterilize instruments, culture media or other substances. However, only heat-resistant materials and devices can be autoclaved, which of course have to fit into the autoclaves.  
Unlike bacteria or spores, nucleic acids cannot be completely eliminated in this way. Under standard autoclaving conditions, the DNA molecules are broken down into fragments of 20 to 30 base pairs. Recent studies show that individual larger DNA fragments can still be detected by PCR analysis. 


Conventional vs. modern decontamination reagents

Special decontamination solutions are available to prevent nucleic acid contamination. Conventional decontamination solutions work with surfactants or acids such as phosphoric or hydrochloric acid, peroxides or strongly alkaline substances such as sodium hydroxide. These agents work according to the principles of modification or renaturation. This masks DNA or RNA residues, but does not destroy them. 

Another disadvantage is that they corrode metal surfaces within a short time and are also harmful or toxic. The high concentrations of acids and bases and must also be neutralized with 100 mM Tris pH 12 or 100 mM Tris pH 3, depending on the composition of the decontamination reagent. 

The latest generation of decontamination reagents, on the other hand, act chemically and only require an incubation time of a maximum of ten minutes. Unlike conventional decontamination agents, the new solutions are non-toxic and non-harmful. The effectiveness of the decontamination is determined by quantitatively examining the DNA degradation. These tests are carried out using analytical agarose gel electrophoresis or PCR tests.  


Notes on the use of decontamination reagents

Not all decontamination reagents are appropriate for all applications; check whether your reagent is suitable for clinical use or only for industrial or research use.