Invited review Towards a plasma treatment of corneal infections E. Martines a,b,n , P. Brun c , P. Brun d , R. Cavazzana b , V. Deligianni e , A. Leonardi f , E. Tarricone d , M. Zuin a,b a Istituto Gas Ionizzati del CNR, Padova, Italy b Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova, Italy c Department of Molecular Medicine, University of Padova, Padova, Italy d Department of Biomedical Sciences, University of Padova, Italy e Department of Ophthalmology, S. Antonio Hospital, Padova, Italy f Department of Neuroscience, Ophthalmology Unit, University of Padova, Padova, Italy article info Article history: Received 3 June 2013 Received in revised form 30 September 2013 Accepted 2 October 2013 Keywords: Keratitis Ophthalmology Cornea abstract Infectious keratitis of the eye is induced by proliferation and penetration of microorganisms in the cornea. The possibility of developing a novel treatment for this condition based on the action of a low temperature, atmospheric pressure plasma is presented. In-vitro results show that bacteria and fungi responsible of keratitis are inactivated by the exposure to the afterglow of a RF plasma produced in a helium flow mixed with ambient air. On the contrary, the viability of corneal cells is not significantly affected. Furthermore, no DNA damage has been detected in the treated cells, suggesting that no long time effects might be induced by this kind of treatment. An increase of intracellular Reactive Oxygen Species (ROS) has been measured following the treatment, suggesting that these chemicals can be involved in the plasma-induced effects. Overall, the presented results point to the feasibility of a plasma- based treatment for infectious keratitis. & 2013 Elsevier GmbH. All rights reserved. Contents 1. Introduction ......................................................................................................... 18 2. Materials and methods ................................................................................................ 18 2.1. Plasma source ................................................................................................. 18 2.2. Treated samples ................................................................................................ 18 2.2.1. Human corneas ......................................................................................... 18 2.2.2. Corneal cells ............................................................................................ 19 2.2.3. Microorganisms ......................................................................................... 19 2.3. Evaluation of effects on corneal tissues ............................................................................. 19 2.3.1. Morphology ............................................................................................ 19 2.3.2. Apoptosis .............................................................................................. 19 2.3.3. DNA damage ........................................................................................... 19 2.4. Evaluation of cultured cell response to treatment ..................................................................... 19 2.4.1. Cell viability ............................................................................................ 19 2.4.2. Intracellular ROS generation ............................................................................... 19 2.4.3. Analysis of cell cycle distribution ........................................................................... 20 2.4.4. Apoptosis .............................................................................................. 20 2.5. Evaluation of microorganism inactivation ........................................................................... 20 3. Results ............................................................................................................. 21 3.1. Cell viability ................................................................................................... 21 3.2. Effects on corneal tissues ........................................................................................ 21 3.3. Intracellular ROS formation ....................................................................................... 22 Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/cpme Clinical Plasma Medicine 2212-8166/$ - see front matter & 2013 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.cpme.2013.10.001 n Corresponding author at: Consorzio RFX, corso Stati Uniti 4, 35127 Padova, Italy. Tel.: þ390498295911; fax: þ390498700718. E-mail address: emilio.martines@igi.cnr.it (E. Martines). Clinical Plasma Medicine 1 (2013) 17–24