Zn-doped and Cu-doped SiOx films were synthesized by atmospheric pressure plasma chemical vapor deposition to study their antibacterial efficiency against Gram-negative Escherichia coli and their cytotoxic effect on the growth of mouse cells. Zn-rich and Cu-rich particles with diameters up to several microns were found to be homogeneously distributed within the SiOx films. For both doping elements, bacteria are killed within the first three hours after exposure to the film surface. In contrast, mouse cells grow well on the surfaces of both film types, with a slight inhibition present only after the first day of exposure. The obtained results indicate that the films show a high potential for use as effective antibacterial surfaces for medical applications.

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The main goal of this investigation was the preparation of an antibacterial layer system for additional modification of wound dressings with atmospheric plasma. Furthermore, the modified wound dressings were checked on there bactericidal and cytotoxic activity. The layer system was applied by using a novel atmospheric pressure plasma chemical vapour deposition technique on a variety of textile substrates which are suitable as wound dressing materials. The layer system composed of silicon dioxide with in situ generated embedded silver nanoparticles. The bactericidal activity of the produced wound dressings was investigated against different bacteria like Staphylococcus aureus and Klebsiella pneumoniae while the cytotoxic potential of the coated wound dressings was verified using human keratinocytes. Even at low concentrations of silver precursor a strong antibacterial effect was observed in direct contact with S. aureus and K. pneumoniae. Furthermore, extractions produced from the coated textiles showed a good antibacterial effect. By means of optimised coating parameters a therapeutic window for those wound dressings could be identified. Consequently, the atmospheric pressure plasma chemical vapour deposition technique promise an effective and low cost modification of wound dressing materials.

Magnetic core-shell nanoparticles of type Fe 3 O 4 @Ag were synthesized in gram scale following a combined co-precipitation phase-transfer method and afterwards, processed to nanoparticle polymer (polypropylene and polyamide) composites. These composites were used as sheath material for the fabrication of core-sheath fibers. During the melt spinning process, a magnetic field was applied around the roving, whereby the particles move in the still liquid sheath polymer towards the surface. The produced fiber materials were investigated by AFM showing a nanostructuring of the surface, which was indirectly confirmed by determination of a slight surface tension lowering. Nanoparticle movement was shown by cross-section SEM and EDX measurements. The antibacterial activity of the spun fibers was proven by contacting them with Escherichia coli. A long-term stability of this effect was observable by carrying out a standard washability test. In contrast to previous works this new approach uses no deposition technique to introduce surface changes. It rather applies a magnetic force to move appropriately equipped nanoparticles from the inside of the fiber to the surface. This leads in only one step to a strong superficial anchoring of the particles resulting in a unique combination of long-term stable antibacterial and improved anti-soiling effects.

Cutaneous candidiasis is characterized by an overgrowth of Candida leading to skin inflammation and infection. Similar to bacteria, Candida can develop tolerance to common antifungal drugs. Cold atmospheric plasma (CAP), with its proven antimicrobial properties, offers a promising alternative to the prevailing methods. Because of plasma heterogeneity each new device must be tested individually for its effectiveness. Antimicrobial activity is usually studied using planktonic microorganisms or animal models, making it difficult to extrapolate the results to the human system. Therefore, a 3D skin model of cutaneous candidiasis for the antimicrobial testing of CAP was established. First, the reaction of the 3D-skin model to Candida infection was examined using various histological and molecular–biological methods. Infection with C. albicans resulted in increased expression and secretion of pro-inflammatory cytokines and augmented expression of antimicrobial peptides. Within 48 h, hyphal growth spread throughout the model and caused tissue damage. Second, the CAP treatment was employed. It was shown that CAP significantly reduced the spread of the yeast in the infected skin models as well as decreased the expression and secretion of the infection markers. The plasma device exhibited a high antifungal activity by completely inhibiting hyphal growth and reducing inflammation at the highest treatment duration.