Nucleic Acid Decontamination 

Anyone working in genomics, PCR labs, 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. Once present, these artifacts are nearly impossible to reduce or remove. Nucleic acid molecules are virtually ubiquitous in the environment - as aerosols, for example - and have proven to be exceptionally stable: researchers in Greenland recently detected two-million-year-old animal DNA fragments.

When Autoclaving is Not Enough

Autoclaving is commonly used in laboratories to sterilize instruments, culture media or other substances. However, only heat-resistant materials and equipment can be autoclaved, and they must fit into autoclaves. Unlike bacteria or spores, nucleic acids cannot be completely eliminated. Under standard autoclaving conditions, 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.

Traditional vs. Advanced Decontamination Reagents

Special decontamination solutions are available to prevent nucleic acid contamination. Conventional decontamination solutions use surfactants or acids such as phosphoric or hydrochloric acid, peroxides, or highly alkaline substances such as sodium hydroxide. These agents work on the principle of modification or renaturation. They mask but do not destroy DNA or RNA residues.

Another disadvantage is that they corrode metal surfaces in a short time and are also harmful or toxic. The high concentrations of acids and bases 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, work chemically and require an incubation time of no more than ten minutes. Unlike conventional decontamination agents, the new solutions are non-toxic and non-harmful. The effectiveness of the decontamination is determined by quantitative testing of DNA degradation. These tests are performed using analytical agarose gel electrophoresis or PCR tests.

Notes on the use of decontamination reagents

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