Tissue Tolerable Plasma Research Articles

Impact of cold atmospheric pressure argon plasma on antibiotic sensitivity of methicillin-resistant Staphylococcus aureus strains in vitro.

Aim: The antimicrobial activity of cold atmospheric pressure plasma (CAP), also called tissue tolerable plasma (TTP), could be a promising option to eradicate methicillin-sensitive as well as methicillin-resistant Staphylococcus aureus strains, which often colonize chronic wounds. Currently, the influence of CAP on the susceptibility of S. aureus to antibiotics is scarcely known, but could be important for treatment of wounds. Therefore, the aim of this study was to investigate whether CAP has an impact on the susceptibility of different S. aureus strains to different antibiotics.Method: For assessment, the agar diffusion test with different antibiotic test disks (cefuroxime, gentamicin, oxacillin, vancomycin, ciprofloxacin, co-trimoxazole, clindamycin, erythromycin) was used. Test strains were spread on agar plates and CAP treated before the antibiotic disks were placed. After 24 hours cultivation, the inhibited growth zones were measured and differences statistically evaluated.Results: In most cases, CAP had a negligible influence on the susceptibility to antibiotics. For two strains, the susceptibility significantly decreased to β-lactam antibiotics. Conclusion: Because CAP can influence the antibiotic susceptibility of S. aureus, before conducting combined treatment with local plasma application on wounds and systemic antibiotics, their interaction must be analysed in vitro to exclude unwanted combination effects.

Adjuvant antifungal therapy using tissue tolerable plasma on oral mucosa and removable dentures in oral candidiasis patients: a randomised double-blinded split-mouth pilot study.

Extended use of antimycotics in oral candidiasis therapy gives rise to problems related to fungal drug resistance. The aim of this pilot study was to investigate the efficacy of tissue tolerable plasma (TTP) in denture stomatitis patients. It was hypothesised that (I): erythema and (IIa): complaint remission would be accelerated and (IIb): colony forming unit (CFU) reduction would be improved. The halves of the upper jaws of eight patients were randomly assigned to control (nystatin, chlorhexidine and placebo treatment) and test sides (nystatin, chlorhexidine and TTP administered six times each 7 days). The patients and the investigators, who were different from the therapists, were both blinded. Compared to the control sides, the erythema surface was reduced significantly more extensively on the test sides between 2 and 6 weeks of antifungal therapy (P ≤ 0.05). Visual analogue scale values and the frequency of moderate or heavy growth of Candida post-treatment did not differ significantly between both sides (P > 0.05). The primary hypothesis was confirmed, which may be interpreted as an accelerated remission. As drug therapy is usually limited to the time in which signs of infection are present, TTP might help reducing antifungal use. Even though the secondary hypotheses were not confirmed, persistence of Candida might be only colonisation.

Bactericidal efficacy of tissue tolerable plasma on microrough titanium dental implants: An in-vitro-study.

Surface decontamination remains challenging in peri-implant infection therapy. To investigate the bactericidal efficacy of tissue tolerable plasma, S. mitis biofilms were created in vitro on 32 microrough titanium dental implants. Biofilm imaging was performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The implants were either rinsed with 1% NaCl as negative control (C) or irradiated with a diode laser (DL) for 60 sec as positive control or plasma (TTP60, TTP120) for 60 or 120 sec. Subsequently, colony forming units (CFU) were counted. Post-treatment, implants were further examined using fluorescence microscopy (FM). Median CFU counts differed significantly between TTP60, TTP120 and C (2.19 and 2.2 vs. 3.29 log CFU/ml; p = 0.012 and 0.024). No significant difference was found between TTP60 and TTP120 (p = 0.958). Logarithmic reduction factors were (TTP60) 2.21, (TTP120) 1.93 and (DL) 0.59. Prior to treatment, CLSM and SEM detected adhering bacteria. Post-treatment FM recorded that the number of dead cells was higher using TTP compared to DL and C. In view of TTP's effectiveness, regardless of resistance patterns and absence of surface alteration, its use in peri-implant infection therapy is promising. The results encourage conducting clinical studies to investigate its impact on relevant parameters.

Effects of physically generated tissue tolerable plasma (TTP) on pancreatic cancer cells in vito and in vivo

Effects of physically generated tissue tolerable plasma (TTP) on pancreatic cancer cells in vito and in vivo

Effects of tissue tolerable plasma in combination with gemcitabine on pancreatic cancer cells

Effects of tissue tolerable plasma in combination with gemcitabine on pancreatic cancer cells

Photodynamic and Tissue Tolerable Plasma Therapies as Alternatives to Antimicrobials to Control Pathogenic Biofilms

The need for novel antimicrobial techniques has become critical for a number of reasons, including the emergence of resistant strains because of excessive prescription and misuse of antibiotics. The mouth is colonized by a large number of microorganisms. When these microorganisms are organized as biofilms they can contribute to chronic diseases in the human population, such as dental caries, candidiasis, and periodontal disease. Hence, alternative antimicrobial approaches have risen to facilitate the treatment of these diseases. As novel therapies, photodynamic antimicrobial chemotherapy and tissue-tolerable plasma are promising methods that offer the possibility of microbial decontamination with decreased odds for the traditional side effects. Thus, the present review aims to offer an overview and future directions of these new approaches to control pathogenic oral biofilms.

Proteomic Changes of Tissue-Tolerable Plasma Treated Airway Epithelial Cells and Their Relation to Wound Healing.

Background. The worldwide increasing number of patients suffering from nonhealing wounds requires the development of new safe strategies for wound repair. Recent studies suggest the possibility of nonthermal (cold) plasma application for the acceleration of wound closure. Methods. An in vitro wound healing model with upper airway S9 epithelial cells was established to determine the macroscopically optimal dosage of tissue-tolerable plasma (TTP) for wound regeneration, while a 2D-difference gel electrophoresis (2D-DIGE) approach was used to quantify the proteomic changes in a hypothesis-free manner and to evaluate the balance of beneficial and adverse effects due to TTP application. Results. Plasma doses from 30 s up to 360 s were tested in relation to wound closure after 24 h, 48 h, 72 h, 96 h, and 120 h, in which lower doses (30, 60, and 120 s) resulted in dose-dependent improved wound healing rate compared to untreated cells. Thereby, the 120 s dose caused significantly the best wound healing properties after 96 and 120 h. The proteome analysis combined with IPA revealed that a lot of affected stress adaptation responses are linked to oxidative stress response emphasizing oxidative stress as a possible key event in the regeneration process of epithelial cells as well as in the adaptation to plasma exposure. Further cellular and molecular functions like proliferation and apoptosis were significantly up- or downregulated by all TTP treatments but mostly by the 120 s dose. Conclusions. For the first time, we were able to show plasma effects on cellular adaptation of upper airway epithelial S9 cells improving wound healing. This is of particular interest for plasma application, for example, in the surgery field of otorhinolaryngology or internal medicine.

Laser scanning microscopy as a means to assess the augmentation of tissue repair by exposition of wounds to tissue tolerable plasma

Confocal laser scan microscopy (CLSM) has emerged as a tool for in vivo assessment of cutaneous conditions. In particular, its use in wound healing assessment has increasingly moved into focus. In this context, the application of tissue tolerable plasma (TTP) for wound treatment has recently become one of the most innovative therapeutic modalities.We analyzed wound healing parameters such as area decline and histomorphological characteristics of tissue repair in six subjects with vacuum-generated wounds on the forearm with a four-armed design: (A) no treatment, (B) treatment with TTP, (C) treatment with octenidine, and (D) sequential treatment with TTP and octenidine. Assessment of the wounds was conducted during six visits over the course of two weeks. The wounds were analyzed by photography and CLSM.TTP treatment led to a more rapid area decline that was statistically significant in comparison to other treatment groups. Besides mild pain, it was well tolerated. Morphologically, wound healing was found to initiate from the edges with the formation of dendritic structures consisting of keratinocytes.CLSM is a valuable tool for assessing the dynamics of wound healing. TTP, for reasons that still need to be investigated, can accelerate wound repair.

Combined antibacterial effects of tissue‐tolerable plasma and a modern conventional liquid antiseptic on chronic wound treatment

Potential antimicrobial effects of sequential applications of tissue-tolerable plasma (TTP) and the conventional liquid antiseptic octenidine dihydrochloride (ODC) were investigated. 34 patients with chronic leg ulcers were treated with TTP, ODC or a combination of both. The bacterial colonization was measured semi-quantitatively before and immediately after treatment and changes in the microbial strains' compositions before and after antiseptic treatments were analyzed. All antiseptic procedures reduced the bacterial counts significantly. The sequential application of TTP and ODC displayed the highest antimicrobial efficacy. Me combined use of TTP and conventional antiseptics might represent the most efficient strategy for antiseptic treatment of chronic wounds.

Efficacy of Tissue Tolerable Plasma (TTP) against Ixodes ricinus.

The efficacy of Tissue Tolerable Plasma (TTP) against ticks was tested, as data from the literature has demonstrated its efficacy against other acari.The study was carried out by using the KINPen09 (Argon as carrier gas) on Ixodes ricinus (n=24). Treatment times of 1 and 3 minutes led to a reversible inactivation of the ticks. After 5 min of treatment, they died.Thanks to the acaricidal effect of TPP, a new treatment strategy using the KINPen09 for tick-infested pets is now available.

Effects of tissue-tolerable plasma on psoriasis vulgaris treatment compared to conventional local treatment: A pilot study

The effect of tissue-tolerable plasma (TTP) on inflammatory diseases such as psoriasis was investigated. Three plaques of six psoriatic patients were subjected to different treatments (A: TTP, brine baths (BB)+5% salicylic acid ointment (SAO); B: BB+SAO; C: BB, UV irradiation, SAO+dithranol). While redness and infiltration was reduced in groups A and C, scaling was reduced in group C. TTP temporarily reduced the bacterial colonization on the skin lesions. In summary, the treatment of psoriatic plaques with TTP showed no significant advantage over conventional therapies.

Comparison of tissue damage caused by various laser systems with tissue tolerable plasma by light and laser scan microscopy

Tissue tolerable plasma (TTP) represents a novel therapeutic method with promising capabilities in the field of dermatological interventions, in particular disinfection but also wound antisepsis and regeneration. The energy transfer by plasma into living tissue is not easily educible, as a variety of features such as the medium’s actual molecule-stream, the ions, electrons and free radicals involved, as well as the emission of ultraviolet, visible and infrared light contribute to its increasingly well characterized effects. Thus, relating possible adversary effects, especially of prolonged exposure to a single component of the plasma’s mode of action, is difficult. Until now, severe adverse events connected to plasma exposure have not been reported when conducted according to existing therapeutic protocols. In this study, we have compared the tissue damage-potential of CO2 and dye lasers with TTP in a porcine model. After exposure of pig ear skin to the three treatment modalities, all specimens were examined histologically and by means of laser scan microscopy (LSM). Light microscopical tissue damage could only be shown in the case of the CO2 laser, whereas dye laser and plasma treatment resulted in no detectable impairment of the specimens. In the case of TTP, LSM examination revealed only an impairment of the uppermost corneal layers of the skin, thus stressing its safety when used in vivo.

Tissue tolerable plasma (TTP) induces apoptosis in the human pancreatic cancer cell line colo-357 in vitro and in vivo

Tissue tolerable plasma (TTP) induces apoptosis in the human pancreatic cancer cell line colo-357 in vitro and in vivo

Tissue Tolerable Plasma (TTP) induces apoptosis in pancreatic cancer cells in vitro and in vivo

BackgroundThe rate of microscopic incomplete resections of gastrointestinal cancers including pancreatic cancer has not changed considerably over the past years. Future intra-operative applications of tissue tolerable plasmas (TTP) could help to address this problem. Plasma is generated by feeding energy, like electrical discharges, to gases. The development of non-thermal atmospheric plasmas displaying spectra of temperature within or just above physiological ranges allows biological or medical applications of plasmas.MethodsWe have investigated the effects of tissue tolerable plasmas (TTP) on the human pancreatic cancer cell line Colo-357 and PaTu8988T and the murine cell line 6606PDA in vitro (Annexin-V-FITC/DAPI-Assay and propidium iodide DNA staining assay) as well as in the in vivo tumour chorio-allantoic membrane (TUM-CAM) assay using Colo-357.ResultsTTP of 20 seconds (s) induced a mild elevation of an experimental surface temperature of 23.7 degree Celsius up to 26.63+/−0.40 degree Celsius. In vitro TTP significantly (p=0.0003) decreased cell viability showing the strongest effects after 20s TTP. Also, TTP effects increased over time levelling off after 72 hours (30.1+/−4.4% of dead cells (untreated control) versus 78.0+/−9.6% (20s TTP)). However, analyzing these cells for apoptosis 10s TTP revealed the largest proportion of apoptotic cells (34.8+/−7.2%, p=0.0009 versus 12.3+/−6.6%, 20s TTP) suggesting non-apoptotic cell death in the majority of cells after 20s TTP. Using solid Colo-357 tumours in the TUM-CAM model TUNEL-staining showed TTP-induced apoptosis up to a depth of tissue penetration (DETiP) of 48.8+/−12.3μm (20s TTP, p<0.0001). This was mirrored by a significant (p<0.0001) reduction of Ki-67+ proliferating cells (80.9+/−13.2% versus 37.7+/−14.6%, p<0.0001) in the top cell layers as well as typical changes on HE specimens. The bottom cell layers were not affected by TTP.ConclusionsOur data suggest possible future intra-operative applications of TTP to reduce microscopic residual disease in pancreatic cancer resections. Further promising applications include other malignancies (central liver/lung tumours) as well as synergistic effects combining TTP with chemotherapies. Yet, adaptations of plasma sources as well as of the composition of effective components of TTP are required to optimize their synergistic apoptotic actions.

Pilot-study on the influence of carrier gas and plasma application (open resp. delimited) modifications on physical plasma and its antimicrobial effect against Pseudomonas aeruginosa and Staphylococcus aureus.

Introduction: Physical plasma is a promising new technology regarding its antimicrobial effects. This is especially accounting for treatment of bacterial infection of chronic wounds. Plasma can be generated with different carrier gases causing various biological effects. Screening of different carrier gases and plasma generation setups is therefore needed to find suitable compositions for highly effective antimicrobial plasma treatments and other applications. Method: The plasma source used was a radio-frequency plasma jet which generates tissue tolerable plasma (TTP). The study compared the antimicrobial efficacy of air, argon, or helium plasma alone or admixed with 0.1%, 0.5%, and 1% oxygen against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Treatment took place in an environmentally open and delimited system. Therefore, bacteria were plated on agar and treated with plasma in a punctiform manner. The resulting inhibition zones were measured and the reduction factors were calculated by colony counting, respectively. Results: For S. aureus and P. aeruginosa, inhibition zones and overall reduction of colony forming units (CFU) on the agar plate were observed while an accumulative reduction of CFU dominated for S. aureus. The highest antimicrobial effect was shown in form of an inhibition zone for argon plasma with 0.1% oxygen admixture for both species. S. aureus was more sensitive for helium plasma with >0.1% oxygen admixture compared to P. aeruginosa which in turn was more sensitive for argon plasma with and without oxygen. The efficacy of air plasma was very low in comparison to the other gases. The treatment in a closed system predominantly enhanced the antimicrobial effect. The effect intensity varied for each treatment time and gas mixtures. Discussion: As expected, the antimicrobial effect mostly increased when increasing oxygen admixture to the carrier gases. The variation in bacterial growth and inhibition after exposure to different plasma gas compositions could be due to a varying generation of reactive oxygen species or radiation. Conclusion: The applied plasma in a “closed system” accumulates bactericidal plasma species and might increase antimicrobial efficacy in clinical settings as in wound management involving multi-drug resistant bacteria.

Comparison of the Antiseptic Efficacy of Tissue-Tolerable Plasma and an Octenidine Hydrochloride-Based Wound Antiseptic on Human Skin

Colonization and infection of wounds represent a major reason for the impairment of tissue repair. Recently, it has been reported that tissue-tolerable plasma (TTP) is highly efficient in the reduction of the bacterial load of the skin. In the present study, the antiseptic efficacy of TTP was compared to that of octenidine hydrochloride with 2-phenoxyethanol. Both antiseptic methods proved to be highly efficient. Cutaneous treatment of the skin with octenidine hydrochloride and 2-phenoxyethanol leads to a 99% elimination of the bacteria, and 74% elimination is achieved by TTP treatment. Technical challenges with an early prototype TTP device could be held responsible for the slightly reduced antiseptic properties of TTP, compared to a standard antiseptic solution, since the manual treatment of the skin surface with a small beam of the TTP device might have led to an incomplete coverage of the treated area.

Corrigendum to: Drug delivery through the skin barrier enhanced by treatment with tissue-tolerable plasma

Corrigendum to: Drug delivery through the skin barrier enhanced by treatment with tissue-tolerable plasma

Skin Disinfection by Plasma-Tissue Interaction: Comparison of the Effectivity of Tissue-Tolerable Plasma and a Standard Antiseptic

Wound healing disorders frequently occur due to biofilm formation on wound surfaces requiring conscientious wound hygiene. Often, the application of conventional liquid antiseptics is not sufficient and sustainable as (1) the borders and the surrounding of chronic wounds frequently consist of sclerotic skin, impeding an effectual penetration of these products, and (2) the hair follicles representing the reservoir for bacterial recolonization of skin surfaces are not affected. Recently, it has been reported that tissue-tolerable plasma (TTP), which is used at a temperature range between 35 and 45°C, likewise has disinfecting properties. In the present study, the effectivity of TTP and a standard liquid antiseptic was compared in vitro on porcine skin. The results revealed that TTP was able to reduce the bacterial load by 94%, although the application of the liquid antiseptic remained superior as it reduced the bacteria by almost 99%. For in vivo application, however, TTP offers several advantages. On the one hand, TTP enables the treatment of sclerotic skin as well, and on the other hand, a sustainable disinfection can be realized as, obviously, also the follicular reservoir is affected by TTP.

Drug delivery through the skin barrier enhanced by treatment with tissue-tolerable plasma

Most treatments in dermatology and cosmetology are based on the penetration of topically applied drugs into the skin or through the skin barrier to the target structure in the living tissue. In the case of healthy skin, scarcely 1% of the applied drugs pass the skin barrier, depending on their chemical properties. Therefore, different physical and chemical methods have been developed to stimulate the penetration process. All these methods are based on the partial destruction of the barrier. In this study, an electrical tissue-tolerable plasma (TTP) was used to increase the penetration of a topically applied model drug (fluorescent dye) through the skin barrier. Using laser scanning microscopy, the distribution of the model drug in different depths of the skin was investigated. It was found that the plasma treatment of the skin is a very efficient process to deliver topically applied substances into the living tissue. In the case of the non-plasma-treated skin, it was found that the fluorescent dye could be detected exclusively on the skin surface. If the dye was applied to the TTP-treated skin, it could be observed in high concentration also in deeper parts of the skin extending down to the stratum basale and the papillary structure.

The modified HET-CAM as a model for the assessment of the inflammatory response to tissue tolerable plasma

Plasma medicine is a novel, highly interdisciplinary field of research. Although the knowledge is rare concerning plasma based biomedical mechanisms, correct dosages and treatment times, animal experiments have been carried out. To follow the 3Rs (reduction, refinement, replacement), it is necessary to define methods for the screening of plasma parameters.In order to determine a reliable test and validate the use of tissue tolerable plasma (TTP) for the treatment of chronic wounds, we have selected the modified hen’s egg test on the chorioallantoic membrane (mod. HET-CAM) as a model to benchmark the inflammation potential of plasma.Inflammations of different intensities provoked by using an HF-plasma jet corresponded to the time of plasma–tissue interaction. Additionally, the plasma mode and the gas composition were changed to assess their influence on the efficacy of treatment. Pulsed plasma led to the mildest inflammation, while the addition of 0.1% oxygen to the argon carrier gas led to the most distinct reaction. It was found that the influence of the exposure time was greater than that of the mode and the gas composition. All inflammations were alleviated, when hydrocortisone (HC) was added immediately after plasma treatment.The results of the study demonstrate that the modified HET-CAM test is suitable for screening plasma sources and for the determination of the optimum parameters for treatment of chronic wounds. To transfer the chronic wound into an acute healing wound without harmful inflammation, the maximum time for plasma–tissue interaction should not exceed 5s with the tested plasma source.Furthermore, it is possible to induce defined plasma-inflammations on the chorioallantoic membrane and to determine the anti-inflammatory potential of test substances.