Experimental contamination by exogenous DNA is a major issue in molecular biological studies for data quality and its management. We herein assessed DNA aerosols for the risk of contamination and tested the capacity of clean air filters to trap and remove DNA aerosols. DNA aerosols were generated by atomizing a DNA solution and introduced into a laminar flow clean air unit. Capture and detection performed upstream and downstream of the clean air unit showed that a significant fraction (>99.96%) of introduced molecules was trapped and removed by the filter. Although DNA aerosols appear to be an avoidable source of exogenous contamination, a clearer understanding and careful experimental procedures are needed in order to perform contamination-free, high-quality molecular biology experiments.

Prevention of airborne contamination has become an important factor in biotechnology; however, conventional laminar-airflow cabinets (LAF-cabinets) are no longer sufficient as a countermeasure against nano-sized airborne contaminants in the laboratory. Here we present a bench-top extra-cleanroom classified as ISO-1 that can prevent contamination from airborne nanoparticles. This bench-top extra-cleanroom consists of a novel clean-zone-creating system that is equipped with nanofibrous, nonwoven filters. In addition, the cleanroom is also equipped with an ionizer to prevent plasticware from collecting dust by electrostatic charge attraction. This combination of features allows the cleanroom to prevent DNA contamination derived from airborne nanoparticles. Our extra-cleanroom with ionizer could be useful in various areas of biotechnology that are easily affected by airborne contaminants.