Design and Development of Non-Equilibrium Plasmas for the Medical Field

There is great interest in the plasma research community on the potential medical applications of non-equilibrium plasmas, called cold atmospheric plasma (CAP), yet currently no such plasma device is approved by the US Food and Drug Administration (FDA). This dissertation seeks to take a holistic look at five novel plasma systems with potential use in the medical field. These systems are all analyzed from an engineering point of view to characterize the plasma and basic biocompatibility from an electrical and thermal approach. The overall design life-cycle for these devices is also examined, with an emphasis on deciding an approval pathway through the Food and Drug Administration, where the intended use of the device is the driving factor. The first device considered is a nanosecond puling circuit devised for skin electroporation. An electrode is developed to help maximize the electric field applied to a substrate and ensure user safety. Voltage and current traces and optical emission spectroscopy are used to characterize the plasma generated for various substrates, showing the non-equilibrium behavior of the plasma for a wide operating range. The second device considered is an existing FDA-cleared electrosurgical device power supply and hand piece, which has been modified for use as a CAP source. By varying the tube length the plasma can be operated in a non-equilibrium state. The third device is a direct write system for depositing thin films in a controlled pattern. This system consists of a dielectric barrier discharge jet attached to a three-dimensional printer head for spatially controlling the plasma location. Various methods of depositing material are used, including directly onto biological substrates. The final two devices are for improving the strength of additively manufactured parts intended for use in custom printed prosthetics. The first is a nanosecond pulsed discharge onto a printed part, which shows 100% strength improvement from the plasma treatment. The second is a planar dielectric barrier discharge mounted onto the head of a three-dimensional printer, which is able to print parts with the same strength as injection molded parts