Author: Matthias Bäcker ; Type of thesis: Foreign Institute Thesis

Due to their unique properties, plasmas have found a broad range of applications in biotechnology and biomedicine, including surface modification of implants and instruments by plasma activation or the deposition of specific diamond-like- and biocompatible structures. A completely new field is the investigation of plasma interaction with biological tissues and the exploration of potential applications.

In contrast to low pressure plasmas, atmospheric pressure plasmas can be operated more conveniently at ambient air and do not require costly vacuum systems. However, the physical properties of a plasma alter significantly with increasing pressure. Therefore, there is a steadily increasing interest in plasma-needles in recent years. These plasma- needles operate stably at atmospheric pressure without producing (filamentary) arcs, but are restricted to their size. Arcs can develop temperatures of several thousand degrees Kelvin and are therefore undesired. The construction of plasma-needle arrays can compensate the reduced effectiveness of a single plasma-needle. The low temperature of the back- ground gas and comparable high electron density of such plasma-needles offer manifold applications.

The objective of this work is the setup of a new atmospheric plasma device for the exploration of its diverse applications with focus on biomedical applications. With the help of comparable work and on the basis of preliminary experiments, a new plasma-needle has been fabricated. Subsequent, that plasma-needle was initially characterized and experimentally tested for thin film deposition and surface modification and is ready for tests on bacteria inactivation.

At first, a review of the state-of-the-art and current research on plasma-needles and their biomedical applications is given. The following two chapters deal with the basics of plasma physics, the experimental setup and the diagnostic tools as well as the principle of the plasma-needle. The results of the different measurements are presented and discussed in chapter five.

The following diagram is intended to help understanding the different steps of the work progress. After an introductory literature review, preliminary experiments with different plasma sources were executed. Thereupon, a prototype was constructed, which then was characterized and tested on two different possible applications, surface activation and carbon film deposition.

Download: Diploma Thesis Matthias Bäcker Aug2007