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P: Plasmaphysik

P 21: Poster: Grundprobleme, Theorie, Plasmatechnologie, Astrophysikalische Plasmen

P 21.31: Poster

Montag, 18. März 2002, 17:40–18:40, HZO Foyer

Recent results on the synergistic effect of oxygen atoms and UV photons in plasma sterilization at reduced gas pressure — •B. Saoudi, M. C. Crevier, M. Moisan, N. Philip, J. Barbeau, and J. Pelletier — Groupe de physique des plasmas, Université de Montréal, Montréal H3C 3J7, Québec

In the reduced-pressure (≤ 10 Torr) afterglow stemming from discharges in O₂-containing mixtures such as N₂−O₂, the test reference spores are ultimately inactivated by UV photons through destruction of their genetic material (DNA), and not by erosion damage, at least when operating under short sterilization time conditions. Sterilization time is actually the shortest when the O₂ percentage in the mixture is set to maximize the UV emission intensity. Under these conditions, using scanning electron and atomic force microscopy, we observe a slight degree of erosion, which we assume to be needed for the UV photons to gain access to the DNA of those spores that are either aggregated or covered by various debris. Increasing the percentage of O₂ in the mixture beyond this optimum setting increases the degree of erosion of the spores by the O radicals. Achieving the sterilization process in the shortest time requires a synergistic action between oxygen atoms and UV photons. Furthermore, plasma sterilization always implies some erosion of the test spores, whereas conventional sterilization methods do not affect significantly their initial dimensions.