24T3
Non-Thermal Atmospheric Plasma for Use in Medical and Hygiene Application
Tetsuji Shimizu, Julia L. Zimmermann and Gregor E. Morfill
Max-Planck Institute for extraterrestrial physics, Giessenbachstr., 85748 Garching,Germany

Non-thermal atmospheric plasma is a potential tool for biomedical applications because it can produce
active agents, e.g. reactive oxygen species, and the treatments without thermal damage can be achieved. Bytuning the produced agents, there are many applications. In this paper, we discuss the current status of ourclinical study for wound care and wound healing. And a possible application for hygiene is also discussed,in particular, hand sanitation.

1. Introduction
A research field of biomedical applications
using cold atmospheric plasma is receiving a
growing attention [1-4]. Cold atmospheric plasma
can play an important role in medicine andhygiene since it has been found to havebactericidal/fungicidal property and regulation
effect of cellular process [5]. It can be applied toliving tissues without a thermal damage and betreated a rough surface in micrometer range. Suchatmospheric plasma contains charged particles,reactive species, heat and photons and they canreact simultaneously on tissues.
In general, plasma has an ability topermeabilize cell walls. When hot plasmas areapplied, the cell walls are chemically andphysically sputtered. Interestingly, even in cold
plasmas this permeabilization process may takeplace in a different manner. There are three
processes under investigation. The first is due tocharging [6]. The charging results to make thecell walls spherical and introduces the surface
stress. The second is due to de-excitation of
excited molecules recombination of charged
particles on the cell wall surface. This gives a
local heating and this heat is located in a verysmall volume since the thermal conductivity of
the cell membrane is low. This local heat can
result in opening of the membrane temporarily.
The third in lipid peroxidation caused by reactivespecies [7]. There are some reports of the cellwall opening up to possibly 5 nm in size [8].
This temporal permiabilization process allows
us to introduce reactive species into the cells.
Since these reactive species produced by theplasma have a high mobility, a faster process ofmolecular application is expected than that using
fluid or ointments. For instance, a bacteria

reduction (plated on agar) of 105 is possible in
10-20 seconds [9].
In this paper, our study in medicine andhygiene using cold atmospheric plasmas is briefly
described. For medical application the current
status of our clinical study in chronic wound careis discussed. For hygiene application, we
demonstrate an atmospheric plasma dispenser forlarge area disinfection, e.g. hands.
2. Medical application: wound care
A clinical study has been carried out incollaboration with Department of Dermatology,
Allergology and Environmental Medicine, Hospital
Munich Schwabing, Department of Dermatology,
University Hospital Regensburg, and Adtec Plasma
Technology Co. Ltd. [10] Fig. 1 shows the clinicaldevice using in the clinics for wound care. At theend of the flexible arm, an argon plasma torch isplaced and the plasma is applied onto wound ofFigure 1. Clinical device for wound treatment.
At the end of flexible arm, the plasma torch isplaced.

patients. The plasma discharge is produced with
~80 W of microwave power at 2.45 GHz and ~2l/min if argon flow inside the plasma torch. The
produced plasma is pushed out with the argon flow
toward the wounds.
Patients received standard wound care besides atwo to five minutes argon plasma treatment on
randomized wound(s) (add-on therapy). The
bacterial load was detected by nitrocellulosis filters,
which give us the germ load as well as spatial
distribution of bacteria on wounds. It was foundthat there was a highly significant reduction ofbacteria counts (~34 %, P < 10-6) in plasma-treatedarea compared with control area. This reduction
was observed in all kinds of bacteria including
resistant bacteria, e.g. MRSA.
3. Hygiene application
A large area scalable and robust electrode designfor plasma production in the ambient air has beendeveloped and tested [9]. The electrode has an
insulator plate sandwiched by a metal plate and a
metal mesh electrode. By applying a high AC
voltage between two metal electrodes, an air plasma
discharge is formed on the mesh electrode as shownin fig. 2. In our study typically 0.5 W/cm2 of power
is applied to the electrode.
By the plasma dispenser shown in fig. 2, it was
shown that a bacterial load reduction of more than
five orders of magnitude was obtained in about 10
seconds for many kinds of bacteria including
anti-biotic resistant bacteria. From the plasma there
are many produced agents relevant to biologicaleffects, e.g. charged particles, reactive oxygen andnitrogen species (O, O3, NO, etc.), UV photons, etc.
Our measurements showed that UV photons alone
didn’t have a bactericidal property. So the reactive
species and charged particles paly an important role.

Figure 2. Plasma device for sanitation. Twoplasma electrodes are equipped.

We are investigating a parameter window in plasma
production in order to have a maximum effect inbactericidal property and a minimum effect onhuman cells.
There are already many researches in the usageof cold atmospheric plasmas for biomedical
applications. Still a large comprehensive study
involving biology, chemistry, physics, medicine, etc.
is necessary and important to achieve the fullpotential of the technology using the cold
atmospheric plasma.
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