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- ItemPlatelets are key in cold physical plasma-facilitated blood coagulation in mice(Amsterdam [u.a.] : Elsevier, 2017) Bekeschus, Sander; Brüggemeier, Janik; Hackbarth, Christine; Woedtke, Thomas von; Partecke, Lars-Ivo; van der Linde, JuliaPurpose: Surgical interventions inevitably lead to destruction of blood vessels. This is especially dangerous in anticoagulated patients. Electrocauterization is a frequently used technique to seal incised tissue. However, leading to a superficial layer of necrotic tissue, the treated area evolves a high vulnerability to contact, making it prone to detachment. As a result, dangerous postoperative bleeding may occur. Cold physical plasma was previously suggested as a pro-coagulant treatment method. It mainly acts by expelling a delicate mixture of oxidants. We therefore tested the suitability of an atmospheric pressure plasma jet (kINPen MED) as a new medical device for sufficient blood coagulation in a murine model of liver incision. Methods: Plasma treatment of murine blood ex vivo induced sufficient coagula. This effect did not affect any tested parameter of plasmatic coagulation cascade, suggesting the mechanism to be related to cellular coagulation. Indeed, isolated platelets were significantly activated following exposure to plasma, although this effect was less pronounced in whole blood. To analyze the biological effect of plasma-on blood coagulation in vivo, mice were anticoagulated (clopidogrel inhibiting cellular and rivaroxaban inhibiting plasmatic hemostasis) or received vehicle only. Afterwards, a partial resection of the left lateral liver lobe was performed. The quantification of the blood loss after liver incision followed by treatment with kINPen MED plasma or electrocauterization revealed a similar and significant hemostatic performance in native and rivaroxaban but not clopidogrel-treated animals compared to argon gas-treated controls. In contrast to electrocauterization, kINPen MED plasma treatment did not cause necrotic cell layers. Conclusion: Our results propose a prime importance of platelets in cold physical plasma-mediated hemostasis and suggest a clinical benefit of kINPen MED plasma treatment as coagulation device in liver surgery.
- ItemCan the effect of cold physical plasma-derived oxidants be transported via thiol group oxidation?(Amsterdam [u.a.] : Elsevier, 2019) Heusler, Thea; Bruno, Giuliana; Bekeschus, Sander; Lackmann, Jan-Wilm; Woedtke, Thomas von; Wende, KristianPurpose: Intra- and intercellular redox-signaling processes where found responsible in various physiological and pathological processes with cellular thiol groups as important signal transducers. Using cold atmospheric plasma (CAP), a similar oxidation pattern of thiol groups can be achieved. Hence, it must be clarified which role extracellular thiol groups play in mediating CAP effects and whether or not the effects of short-lived reactive species can be preserved in a molecule like cysteine. Methods: Physiological buffer solutions containing the amino acid cysteine were treated by an MHz argon plasma jet with molecular gas admixtures (kINPen) and transferred to cultured human keratinocytes. Cell proliferation, migratory activity, and metabolism were investigated. High-resolution mass spectrometry was used to estimate the impact of plasma generated species on thiol groups. Results: While treated physiologic cysteine concentrations showed no impact on cell behavior, artificially high concentrations decreased proliferation, migration and lactate secretion. GSH levels inside cells were stabilized. Conclusion: Extracellular thiol groups scavenge plasma-generated species and form a multitude of covalent modifications. Unexpectedly, human keratinocytes show only small functional consequences for treated physiologic cysteine concentrations. Results for high concentrated cysteine solutions indicate an improved cytostatic/cytotoxic impact by plasma treatment suggesting a potential application as a “preserving agent” of the chemical energy of plasma-derived species. © 2019 The Authors
- ItemFirst insights on plasma orthodontics - Application of cold atmospheric pressure plasma to enhance the bond strength of orthodontic brackets(Amsterdam [u.a.] : Elsevier, 2016) Metelmann, Philine H.; Quooß, Alexandra; Woedtke, Thomas von; Krey, Karl-FriedrichObjective: The development of an ideal adhesive system has long been subject of research. Recent studies show that treatment with cold atmospheric pressure plasma (CAP) positively affects the bonding properties of enamel. Conditioning with CAP could therefore improve the mechanical and physical properties of bracket adhesives, e.g. Glass ionomer cement (GIC). Material and methods: Laser-structured brackets (Dentaurum, Ispringen) were bonded onto 60 bovine mandibular incisors using different orthodontic adhesives. For 20 specimens FujiOrthoLC (GC America Corp, Alsip, USA) was used according to manufacturer's instructions. Another 20 specimens received a 60 s CAP-treatment (kINPen med, Neoplas tool, Greifswald, Germany) before bracket bonding, of which 10 were re-moistened before applying FujiOrthoLC and 10 remained dry. Onto 20 specimens, brackets were bonded with the Composite Transbond XT (3M/Unitek, St. Paul, USA) following manufacturer's instructions. The shear bond strength of brackets on the teeth was determined with the universal testing machine Zwick BZ050/TH3A (Zwick, Ulm, Germany). Results: Brackets bonded with FujiOrthoLC in standard method, showed average shear bond strength of 5.58±0.46 MPa. Specimens treated with plasma showed clinically unacceptable adhesion values (re-moistened group: 2.79±0.38 MPa, dry group: 1.01±0.2 MPa). Bonding onto dried out teeth also led to spontaneous bracket losses (4 of 10 specimens). The composite group (Transbond XT) showed clinically acceptable adhesion values (7.9±1.03 MPa). Conclusions: Despite promising potential, surface conditioning with CAP could not improve the adhesive properties of GIC. By contrast, a decrease in shear bond strength was noticed after CAP treatment. Further investigations have to show whether it is possible to increase the retention values of other orthodontic adhesives by CAP application and thus take advantage of positive characteristics and reduce side effects.
- ItemCold physical plasma-induced oxidation of cysteine yields reactive sulfur species (RSS)(Amsterdam [u.a.] : Elsevier, 2019) Bruno, Giuliana; Heusler, Thea; Lackmann, Jan-Wilm; Woedtke, Thomas von; Weltmann, Klaus-Dieter; Wende, KristianPurpose: Studying plasma liquid chemistry can reveal insights into their biomedical effects, i.e. to understand the direct and indirect processes triggered by the treatment in a model or clinical application. Due to the reactivity of the sulfur atom, thiols are potential targets for plasma- derived reactive species. Being crucial for protein function and redox signaling pathways, their controllable modification would allow expanding the application range. Additionally, models to control and standardize CAP sources are desired tools for plasma source design. Methods: Cysteine, a ubiquitous amino acid, was used as a tracer compound to scavenge the reactive species produced by an argon plasma jet (kINPen). The resulting product pattern was identified via high-resolution mass spectrometry. The Ellman´s assay was used to screen CAP derived thiol consumption, and long-lived species deposition (hydrogen peroxide, nitrite, nitrate) was monitored in relation to the presence of cysteine. Results: The intensity of cysteine oxidation increased with treatment time and availability of oxygen in the feed gas. A range of products from cysteine was identified, in part indicative for certain treatment conditions. Several non-stable products occur transiently during the plasma treatment. Bioactive reactive sulfur species (RSS) have been found for mild treatment conditions, such as cysteine sulfoxides and cysteine-S-sulfonate. Considering the number of cysteine molecules in the boundary layer and the achieved oxidation state, short-lived species dominate in cysteine conversion. In addition, a boundary layer depletion of the tracer was observed. Conclusion: Translating these data into the in-vivo application, strong direct oxidation of protein thiol groups with subsequent changes in protein biochemistry must be considered. Plasma-derived RSS may in part contribute to the observed biomedical effects of CAP. Care must be taken to control the discharge parameter tightly as chemical dynamics at or in the liquid are subject to change easily. © 2019