Development of a bench-top extra-cleanroom preventing DNA contamination from airborne nanoparticles for DNA analysis with high reliability

Hirokazu Takahashi, a postdoctoral researcher, and Yoshiko Okamura, an Associate Professor of Hiroshima University announced a bench-top extra-cleanroom classified as ISO-1 (>10 particles/m³) developed by a research group composed of Hiroshima University, National Agriculture and Food Research Organization and Koken Ltd. It can prevent DNA contamination derived from airborne nanoparticles sufficiently and stably and enables DNA analysis based on infinitesimal cells with high reliability.

With the high ability of ø29 DNA polymerase, infinitesimal amounts of genomic DNA can be amplified via whole-genome amplification (WGA). However WGA based on a non-specific amplification method using random primers is easily affected by contaminants. Conventional Laminar-flow cabinet classified as ISO-5 cannot perfectly prevent invasion by airborne nano-particles. Indeed, many airborne nano-particles (2.0 × 10⁴ to 3.5 × 10⁴ particles/m³, mainly 0.1 µm in size) were detected in the LAF-cabinet.

In this study published in Bio Techniques, the authors revealed that airborne nano-particles contained a small part of human- and fungal-chromosomal DNA, vector-like DNA and unknown DNA and randomly contaminated into tubes independent of place and time. Therefore, a bench-top extra-cleanroom was developed and the frequency of DNA contamination in ISO-1 was compared with that in ISO-5. The result showed that new developed cleanroom succeeded to prevent contamination in DNA amplification procedures perfectly and guaranteed the high quality of DNA amplicon.

Despite its higher cleanliness classification, the bench-top extra-cleanroom is much less expensive than conventional cleanroom systems. Therefore, this cleanroom is expected to be used in metagenomic studies of unculturable organisms and in any other life science and medical studies.