A kit of parts is provided, which includes a plasma generating device 20 and a membrane dressing 30. The plasma generating device comprises a first cavity 29 with an opening at one end formed between a cathode 23 and a grounded electrode 24 such that, in use, an arc discharge ionizes a feed gas to produce a thermal plasma and a second cavity 35 with an opening at one end formed between a grounded electrode 24 and a high voltage electrode 25 such that, in use, a dielectric barrier discharge between ionizes a feed gas to produce a non-thermal plasma. The membrane dressing 30 is a sheet of impermeable material having one or more input connectors 31, and functions to contain the plasma adjacent to the tissue. The membrane dressing is at least partially transparent, and forms a peripheral seal 32 with tissue around the damage site. The plasma generating device may have a concentric arrangement, with the cathode 23 as a central rod, the grounding electrode 24 as a tube around the rod, and the high-voltage electrode 25 around the tube, such that the second cavity 35 is coaxial with the first cavity 29, see figure 2B.
