Cold Plasma Devices Research Articles

Transformation Dynamics of Nanosized Bi Films into Semiconductor Films of Bismuth Oxide in the Cold Plasma Device

This work proposes an original method that reveals the transformation dynamics of nanosized Bi films into semiconductor films of bismuth oxide (Bi2O3) and the factors affecting the low‐energy cold plasma on the electro‐optical properties of Bi2O3. In the plasma microreactor with a photosensitive GaAs:Cr electrode, the transformed Bi films 400–1100 nm thick are analyzed by X‐ray diffraction to determine the crystal structure of Bi2O3 and by an electron probe microanalyzer to explore the evolution of the composition. The morphological properties of the Bi films exposed to electron–ion flow are examined by processing the scanning electron microscope images. It is found that as a result of the combined effect of photoactive illumination, charged particles, and active plasma components: 1) an absorption spectrum of a new substance is formed in the range λ = 330–1100 nm; 2) the optical width of the bandgap of the resulting substance is Eg ≈ 3 eV, which satisfactorily coincides with the width of the bandgap of Bi2O3; and 3) to overcome the potential barrier and formation of semiconducting Bi2O3 film energy is required, which is provided by the combined kinetic energy of electrons and negatively charged oxygen ions bombarding on the Bi film.

Investigating cold plasma jet effectiveness for eggshell surface decontamination

Ensuring the safety of eggs, a valuable source of high-quality protein and essential vitamins, is critical to prevent foodborne illness. Cold plasma, an emerging green technology, generates various reactive species that effectively inactivate microorganisms, attracting global attention for its potential in food safety. This study aims to explore the application of cold plasma as a chemical-free, non-thermal approach for decontaminating egg surfaces and to assess its potential as an alternative to conventional egg-washing methods. Various operation conditions of a cold plasma jet device, including power levels (300–400 W), exposure times (20–60 s), distances between the nozzle and eggshell (1–3 cm), airflow rates (30–35 L/min), and feed gases (nitrogen, air (20 %–65 % relative humidity), helium and air mixtures), were examined to decontaminate hen eggshells inoculated with Escherichia coli and Salmonella enterica bacteria. The results showed a maximum log reduction and deactivation efficiency of 1.94 and 98.74 % for E. coli, and 1.11 and 92.20 % for Salmonella, after a 60 s treatment of egg surface using a cold plasma device set at 1 cm distance, 400 W power, and 35 L/min airflow with 65 % relative humidity. Moreover, our findings indicated no significant differences in egg quality, eggshell cuticle chemical composition, and cuticle coverage between untreated eggs and those treated with cold plasma. This suggests the potential of this non-chemical, non-thermal emerging technique to be commercialized as a substitute for conventional washing methods.

Efficacy, kinetics, inactivation mechanism and application of cold plasma in inactivating Alicyclobacillus acidoterrestris spores

As spores of Alicyclobacillus acidoterrestris can survive traditional pasteurization, this organism has been suggested as a target bacterium in the fruit juice industry. This study aimed to investigate the inactivation effect of cold plasma on A. acidoterrestris spores and the mechanism behind the inactivation. The inactivation effect was detected by the plate count method and described by kinetic models. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), the detection of dipicolinic acid (DPA) release and heat resistance detection, the detection and scavenging experiment of reactive species, and cryo-scanning electron microscopy were used to explore the mechanism of cold plasma inactivation of A. acidoterrestris. The results showed that cold plasma can effectively inactivate A. acidoterrestris spores in saline with a 3.0 ± 0.3 and 4.4 ± 0.8 log reduction in CFU/mL, for 9 and 18 min, respectively. The higher the voltage and the longer the treatment time, the stronger the overall inactivation effect. However, a lower gas flow rate may increase the probability of spore contact with reactive species, resulting in better inactivation results. The biphasic model fits the survival curves better than the Weibull model. SEM and TEM revealed that cold plasma treatment can cause varying degrees of damage to the morphology and structure of A. acidoterrestris spores, with at least 50 % sustaining severe morphological and structural damage. The DPA release and heat resistance detection showed that A. acidoterrestris spores did not germinate but died directly during the cold plasma treatment. 1O2 plays the most important role in the inactivation, while O3, H2O2 and NO3− may also be responsible for inactivation. Cold plasma treatment for 1 min reduced A. acidoterrestris spores in apple juice by 0.4 ± 0.0 log, comparable to a 12-min heat treatment at 95 °C. However, as the treatment time increased, the survival curve exhibited a significant tailing phenomenon, which was most likely caused by the various compounds in apple juice that can react with reactive species and exert a physical shielding effect on spores. Higher input power and higher gas flow rate resulted in more complete inactivation of A. acidoterrestris spores in apple juice. What's more, the high inactivation efficiency in saline indicates the cold plasma device provides a promising alternative for controlling A. acidoterrestris spores during apple washing. Overall, our study provides adequate data support and a theoretical basis for using cold plasma to inactivate A. acidoterrestris spores in the food industry.

Design and Application of High-Density Cold Plasma Devices Based on High Curvature Spiked Tungsten Structured Electrodes

Advances in radar technology have driven efforts to develop effective countermeasures. Plasma is recognized as a highly effective medium for absorbing electromagnetic waves. Recent research has focused on enhancing plasma element performance. This paper achieved ultra-high-density, low-pressure cold plasma with a density of 1.15 × 1012 cm−3, surpassing similar studies by more than an order of magnitude. Tungsten electrodes with high-curvature spiked structures were invented to replace traditional iron–nickel alloy electrodes, increasing plasma density by 88.2% under the same conditions. Lightweight and cost-effective tubular and annular ultra-high-density, low-pressure cold plasma devices were developed, demonstrating exceptional performance in electromagnetic wave absorption, plasma transient antennas, and radar stealth technology. The influence of plasma on electromagnetic waves and its numerical relationship were analyzed. By measuring the radar cross-section (RCS), the reduction in radar detection rates was quantified. The results show that the ultra-high-density cold plasma devices exhibit very low intrinsic RCS values, suitable for plasma antenna applications. The array of plasma elements generates a large-area high-density low-pressure cold plasma. This plasma effectively reduces the radar cross-section (RCS) of metallic equipment in the S and C bands and shows attenuation in the X band. These effects highlight the superior characteristics of plasma technology in electronic warfare. This exploratory research lays the groundwork for further defense applications.

Effects of cold plasma on the growth and aflatoxin production of Aspergillus flavus

Cold plasma (CP) has an inactivating effect on bacteria, but little research has been done on fungi, especially on aflatoxin (AF)-producing strains of Aspergillus flavus (A. flavus). In this study, a CP device was utilized to investigate the destructive effects and mechanisms of different voltage treatments on AF-producing A. flavus strains. The inactivation curve was fitted using Weibull and Logistics kinetic models (R2 > 0.930). The results of viable spore count and AF detection showed that after 6 min of 60 V treatment, the total number of viable spores decreased by 4.47 log10 CFU/mL, and the AF level was found to be significantly lower after treatment (p < 0.05). The microstructure of A. flavus spores was severely damaged after DBDP treatment. The leakage of nucleic acids and proteins, lipid oxidation level, reactive oxygen level, and Fourier transform infrared spectroscopy analysis of spores all confirmed that the cell membrane of A. flavus was damaged after DBDP treatment. This study could provide reference methods for CP technology in the control of AF-producing A. flavus.

Training in the use of the water jet and cold atmospheric plasma jet for the decontamination of dental implants

ObjectivesClinical trials testing new devices require prior training on dummies to minimize the "learning curve" for patients. Dentists were trained using a novel water jet device for mechanical cleaning of dental implants and with a novel cold plasma device for surface functionalisation during a simulated open flap peri-implantitis therapy. The hypothesis was that there would be a learning curve for both devices.Materials and methods11 dentists instrumented 44 implants in a dummy-fixed jaw model. The effect of the water jet treatment was assessed as stain removal and the effect of cold plasma treatment as surface wettability. Both results were analysed using photographs. To improve treatment skills, each dentist treated four implants and checked the results immediately after the treatment as feedback.ResultsWater jet treatment significantly improved from the first to the second implant from 62.7% to 75.3% stain removal, with no further improvement up to the fourth implant. The wettability with cold plasma application reached immediately a high level at the first implant and was unchanged to the 4th implant (mean scores 2.7 out of 3).ConclusionA moderate learning curve was found for handling of the water jet but none for handling of the cold plasma.Clinical relevanceScientific rational for study: Two new devices were developed for peri-implantitis treatment (Dental water jet, cold plasma). Dentists were trained in the use of these devices prior to the trial to minimize learning effects.Principal findings: Experienced dentists learn the handling of the water jet very rapidly and for cold plasma they do not need much training.Practical implications: A clinical study is in process. When the planned clinical study will be finished, we will find out, if this dummy head exercise really minimised the learning curve for these devices.

Design and Development of a Novel Tesla Coil-Based Cold Plasma Device for Plasma Medicine: Decoupling the Effect of Plasma-Generated Species

Design and Development of a Novel Tesla Coil-Based Cold Plasma Device for Plasma Medicine: Decoupling the Effect of Plasma-Generated Species

DBD plasma as a practical approach to sterilization of dental instruments

Microbe control and decontamination are necessary for medical equipment that will be used again. Several wet and dry sterilizer technologies, like as autoclaves, ovens, UV systems, and chemical agents, have been widely used to eliminate the possibility of cross-infection between contaminated dental instruments or materials and dental patients. The development of a sterilizer device capable of sterilizing dental equipment through non-toxic materials has been shown to significantly decrease the overall procedure time compared to conventional approaches. Therefore, an investigation was conducted to assess the efficacy of a dielectric barrier discharge (DBD) plasma device in sterilizing dental instruments under atmospheric pressure conditions. Also, due to Reactive Oxygen and Nitrogen Species (RONS) existence at low temperatures, researchers have been examining the biological effects of cold plasmas for medical applications with promising results. The dental Tweezer, one of the dental tools, was chosen to perform the sterilization process using the DBD plasma device. The Dental Tweezers samples were contaminated with Escherichia coli and Staphylococcus aureus bacteria, and then the DBD plasma device was used to sterilize them for 1, 2, 3, and 4 min, respectively, to figure out the best time to do this. The DBD plasma device successfully killed E. coli and S. aureus. Based on the findings derived from our present investigation, the cold plasma device has impressively proven its efficiency in sterilization.

Cold atmospheric plasma is bactericidal to wound-relevant pathogens and is compatible with burn wound healing

Burn wound healing can be significantly delayed by infection leading to increased morbidity and hypertrophic scarring. An optimal antimicrobial agent would have the ability to kill bacteria without negatively affecting the host skin cells that are required for healing. Currently available products provide antimicrobial coverage, but may also cause reductions in cell proliferation and migration. Cold atmospheric plasma is a partially ionized gas that can be produced under atmospheric pressure at room temperature. In this study a novel handheld Aceso Plasma Generator was used to produce and test Aceso Cold Plasma (ACP) in vitro and in vivo. ACP showed a potent ability to eliminate bacterial load in vitro for a number of different species. Deep partial-thickness and full-thickness wounds that were treated with ACP after burning, after excision, after autografting, and at days 5, 7, and 9 did not show any negative effects on their wound healing trajectories. On par with in vitro analysis, bioburden was decreased in treated wounds vs. control. In addition, metrics of hypertrophic scar such as dyschromia, elasticity, trans-epidermal water loss (TEWL), and epidermal and dermal thickness were the same between the two treatment groups.It is likely that ACP can be used to mitigate the risk of bacterial infection during the phase of acute burn injury while patients await surgery for definitive closure. It may also be useful in treating wounds with delayed re-epithelialization that are at risk for infection and hypertrophic scarring. A handheld cold plasma device will be useful in treating all manner of wounds and surgical sites in order to decrease bacterial burden in an efficient and highly effective manner without compromising wound healing.

Reduction of microbial population of fresh vegetables (carrot, white radish) and dried fruits (dried fig, dried peach) using atmospheric cold plasma and its effect on physicochemical properties

Non-observance of hygiene principles during storage causes excessive growth of microorganisms in these products and the return of export products to the manufacturer. The purpose of this research is to examine the antimicrobial effects of the jet cold plasma device and its impact on the physicochemical and sensory characteristics of a carrot, white radish, dried fig, and dried peach. For this purpose, the samples were inoculated with Escherichia coli O157:H7, Enterococcus faecalis, and Aspergillus niger. Then samples were treated with atmospheric cold plasma in the form of a jet probe and DC pulse source with 17 KV and 2.26A for 0, 3, 6, 9, and 12 min. The results showed that the rate of inactivation of microorganisms increases with increasing exposure time to atmospheric cold plasma. The maximum reduction of the microbial load was observed at 17 kV and 12 min. The resistance of microorganisms in dried fig and dried peach was higher than in carrot and white radish due to lower humidity. Also, A. niger showed the highest resistance to cold plasma compared with E. coli O157:H7, and E. faecalis. By comparing the average indices of a, and b, no significant change was observed between the treated and the control samples (p > 0.05). The texture structure remained intact after plasma application, and the plasma had no destructive effect on the texture. The samples treated with cold plasma did not show a significant effect on the physicochemical and sensory characteristics of different food products. Therefore, atmospheric cold plasma technology can be used as an efficient maintenance technique to enhance the shelf life of food products.

Spatio-temporal species kinetics, thermal and electrical field evolution in an argon EFCAP under different rates of nitrogen seeding: A one-dimensional simulation study

Nitrogen seeding is crucial in cold plasma devices for production of reactive nitrogen species. Excitation Frequency Controlled Cold Atmospheric Pressure Plasma (EFCAP) devices belong to recent concepts in cold plasma where discharge kinetics can be controlled via tuning of external field frequency. The study presents time dependent modelling of such an atmospheric pressure non-DBD argon discharge between two bare electrodes in one dimension under different rates on nitrogen seeding using commercial software COMSOL Multiphysics version 5.4. A square alternating high voltage power source of frequency 11 kHz and peak voltage of 500V drives the discharge in the model. In every half-period, there is an electrical breakdown. Spatio-temporal variations in the electron density, ion density, electric field, electric potential, and electron temperature are investigated. Observed unique spatial oscillations in the species densities, species temperature and distinct drift in the observed characteristics with different rates of nitrogen seeding are some of the appealing aspects revealed by the study. The excitation and dissociation of molecules, generation and losses of ions, plasma mediated reactions and collisional excitations are accounted elaborately in the model developed. The study could explain the origin of typical non-uniform discharge patterns reported experimentally under different excitation frequencies in EFCAP. Obtained results are expected to be useful for better understanding of device physics towards development of improved cold plasma sources with desired characteristics.

Cold plasma for sustainable control of hygienically relevant biofilms. The interaction of plasma distance and exposure time

ABSTRACT This study aimed to analyse the efficacy of a new cold plasma device adapted for treatment with a low power consumption . We tested the reduction of bacterial cells in biofilms of E. coli, S. aureus and P. aeruginosa. . The results show significant differences between bacterial cells, suggesting that Gramme-positive S. aureus is less susceptible to plasma treatment than Gramme-negative E. coli and P. aeruginosa. Increasing the exposure time and decreasing the distance decreases the number of cells in the biofilm. However, the combination of close distance and long exposure time resulted in synergistic effects. We demonstrated a reduction of up to 6.6 log CFU cm2 for E. coli at 1 mm and an exposure time of 60 seconds. All these indicate that the new cold plasma jet device can be an important key to ensuring hygiene and numerous applications in medicine and engineering are possible.

Study of unique aspects of oxidative-nitrosative environment in a radio frequency cold plasma device

The study reports unique aspects of oxidative and nitrosative environment and generation of radicals in a newly developed 13.56 MHz cold atmospheric pressure plasma jet (APPJ) device using optical emission spectroscopy (OES). Signature of generated species, species density, energy, their spatial variation and interaction with liquid medium are investigated. While techniques to achieve controlled generation of atomic oxygen and nitrogen in the same device are identified, distinct ability of pure argon APPJ to break oxygen molecules in air releasing atomic oxygen is an interesting finding. Boltzmann plot technique is used to determine the electron excitation temperature. Time averaged gas temperature is measured using mercury thermometer as well as matching simulated and experimental spectra of A-X band of OH radical. Electron density is determined from spectral broadening of Hα line. Formation of OH radical is detected via its signature A-X band. Measured electron density and electron excitation temperature are of the order of 1021 per m3, and 3 eV respectively at the nozzle exit. Standard test strips are used to investigate generation of H2O2, NO2 and NO3 radicals through interaction of the plasma jet with water as a function of time.

Evaluation of Virucidal Efficacy of Cold Plasma on Bacteriophage Inside a Three-Layered Sterilization Chamber

Traditional disinfection methods against pathogens have numerous shortcomings, and inventive methods like cold plasma are required for virus inactivation. Here, an atmospheric pressure 13.56 MHz radio-frequency hollow cathode (RF–HC) cold plasma device has been used to build a cold plasma sterilization device, and its virucidal activity is assessed against P2 bacteriophage, a model surrogate for pathogenic viruses. The heart of this device contains a three-layered sterilization chamber which is a rectangular parallelopiped of 42 × 32 × 30 cm3. Optimization experiments were performed to make each corner of this chamber completely virus free after cold plasma treatment. This two-pronged study was conducted to establish the requirement of minimum vol. % H2O2 in minimum time for the complete elimination of phages inside this sterilization chamber even when plasma is not in the direct line of sight. In initial experiments, the effect of the direct plasma line of sight was seen as the top and bottom layers showing less phage killing as compared to the middle of the sterilization chamber. Complete sterilization of bacteriophage, in all the three layers inside the sterilization chamber, was achieved by plasma treatment with 6% H2O2 for 10 min in 80 watts of plasma operating power. It was also seen that 6% H2O2 mist alone is not sufficient to provide a high degree of sterilization, and normal water mist combined with cold plasma can provide a higher level of sterilization at each corner of the chamber.

In vivo study of the effects of a portable cold plasma device and vitamin C for skin rejuvenation

Nowadays, cold atmospheric plasma shows interesting results in dermatology. In the present study, a new portable cold plasma was designed for plasma skin rejuvenation (PSR) purposes. This device is safe and easy to use at beauty salons and homes. The effects of this device were investigated on the rat skins. Also, as a new method to improve PSR results, vitamin C ointment was combined with plasma. In this study, there were four groups of 5 Wistar rats. The first group received vitamin C ointment, the second received 5 min of high-voltage plasma, and the third and the fourth groups received 5 min of high- and low-voltage plasma and vitamin C ointment. This process was done every other day (3 sessions per week) for 6 weeks. To evaluate the thermal effect of plasma, the skin temperature was monitored. Also, the presence of reactive species was demonstrated by the use of optical spectroscopy. In addition, mechanical assays were performed to assess the effect of plasma and vitamin C on the tissue’s mechanical strength. The mechanical assays showed a positive impact of plasma on the treated tissue compared to the control group. Also, changes in the collagen level and thickness of the epidermal layer were examined in histological studies. The results indicated an increase in collagen levels after using plasma alone and an accelerated skin reaction after using vitamin C combined with plasma therapy. The epidermal layer’s thickness increased after applying high-voltage plasma, which indicates an increase in skin elasticity. This study demonstrates the positive effect of using the portable plasma device with vitamin C ointment on effective parameters in skin rejuvenation.

Antibacterial and safety tests of a flexible cold atmospheric plasma device for the stimulation of wound healing

Cold atmospheric plasma (CAP) devices generate an ionized gas with highly reactive species and electric fields at ambient air pressure and temperature. A flexible dielectric barrier discharge (DBD) was developed as an alternative antimicrobial treatment for chronic wounds. Treatment of Staphylococcus aureus in collagen-elastin matrices with CAP for 2 min resulted in a 4 log reduction. CAP treatment was less effective on S. aureus on dermal samples. CAP did not affect cellular activity or DNA integrity of human dermal samples when used for up to 2 min. Repeated daily CAP treatments for 2 min lowered cellular activity of dermal samples to 80% after 2 to 4 days, but this was not significant. Repeated treatment of ex vivo human burn wound models with CAP for 2 min did not affect re-epithelialization. Intact skin of 25 healthy volunteers was treated with CAP for 3× 20” to determine safety. Although participants reported moderate pain scores (numerical rating scale 3.3), all volunteers considered the procedure to be acceptable. Severe adverse events did not occur. CAP treatment resulted in a temporarily increased local skin temperature (≈3.4°C) and increased erythema. Lowering the plasma power resulted in a significantly lower erythema increase. Good log reduction (2.9) of bacterial load was reached in 14/15 volunteers artificially contaminated with Pseudomonas aeruginosa. This study demonstrated the in vitro and in vivo safety and efficacy in bacterial reduction of a flexible cold plasma device. Trial registration number NCT03007264, January 2, 2017Key Points• CAP strongly reduced bacterial numbers both in vitro and in vivo.• Re-epithelialization of burn wound models was not affected by repeated CAP.• CAP treatment of intact skin was well tolerated in volunteers.

The antimicrobial and tissue healing efficacy of the atmospheric pressure cold plasma on grade III infected pressure ulcer: randomized controlled in vivo experiment.

To evaluate the antimicrobial efficacy and wound healing effect of atmospheric pressure cold plasma (APCP) on an infected pressure ulcer (IPUs) model that was created on rats. A total of 18 rats was divided into APCP, silver sulfadiazine (AgS) and control groups to have six rats in each group. A third-grade pressure ulcer model was developed on the back of each of the rats, and pressure ulcers were infected by inoculation of multidrug resistance (MDR) Pseudomonas aeruginosa. A portable dielectric barrier discharge device was used to generate cold air plasma. APCP, AgS and saline treatments were carried out once a day for 14days. The effectiveness of the treatment was evaluated on days 5, 10 and 15. Surface area, depth, pressure ulcer healing scale (PUSH) and microbiological examination were used for evaluation. The results of this study showed that APCP was superior over AgS application and irrigation with saline by means of the reduction in surface area and depth of ulcers. Furthermore, PUSH score in plasma group was lower than other groups and histopathological examination showed a higher epithelization in APCP group. The average reductions of MDR P. aeruginosa for APCP, AgS and control groups were determined as 5·64±1·87, 1·91±0·90 and 1·22±0·88 log10 CFU per gram tissue, respectively. Atmospheric pressure cold plasma healed IPUs better than AgS. Portable cold plasma devices could be a potential novel treatment modality for the patients who have IPUs.

Inhibition of murine melanoma tumor growth in vitro and in vivo using an argon-based plasma jet

BackgroundIn recent years, cold physical plasma gained significant interest as a new anticancer tool. Cold plasmas are versatile apparatuses in medicine and material processing. Among different cold plasma devices, the argon plasma jet is an effective apparatus and favorite for researches in plasma medicine science. MethodsWe developed an argon plasma jet for cancer treatments. Using optical emission spectroscopy, the newly developed plasma jet produced a substantial amount of hydroxyl radicals and other reactive oxygen and nitrogen species known to show cytotoxic effects at higher concentrations. In this work, we studied the efficacy of the argon-based plasma jet treatment in murine B16 melanoma cells in vitro and in vivo. In vitro, cell viability, apoptotic gene expression, and cell death patterns were assessed at 24 h and compared against non-malignant murine dermal fibroblasts (MDF). In vivo, B16 cells inoculated into the flank of the mice developed melanoma tumors, which were plasma-treated for 5 min on days 1, 5, and 10 or were left untreated. ResultsMelanoma cells were significantly more sensitive to plasma treatment than MDF under the same in vitro conditions (p= 0.00023). The results revealed that the argon-based plasma jet damaged B16 melanoma cells in vitro selectively without a detrimental effect on non-malignant MDF cells. In the animal model, the tumor volume was significantly reduced after three treatments with the plasma jet(p< 0.01). ConclusionsThe argon plasma jet showed therapeutic anti-melanoma efficacy in vitro and in vivo, which may spur new research lines in melanoma therapy.

Cold atmospheric plasma is a viable solution for treating orthopedic infection: a review.

Bacterial infection and antibiotic resistance are major threats to human health and very few solutions are available to combat this eventuality. A growing number of studies indicate that cold (non-thermal) plasma treatment can be used to prevent or eliminate infection from bacteria, bacterial biofilms, fungi and viruses. Mechanistically, a cold plasma discharge is composed of high-energy electrons that generate short-lived reactive oxygen and nitrogen species which further react to form more stable compounds (NO2, H2O2, NH2Cl and others) depending on the gas mixture and plasma parameters. Cold plasma devices are being developed for medical applications including infection, cancer, plastic surgery applications and more. Thus, in this review we explore the potential utility of cold plasma as a non-antibiotic approach for treating post-surgical orthopedic infections.

Computational Fluid Dynamics Analysis of Cold Plasma Plume Mixing with Blood Using Level Set Method Coupled with Heat Transfer

Cold plasmas were proposed for treatment of leukemia. In the present work, conceptual designs of mixing chambers that increased the contact between the two fluids (plasma and blood) through addition of obstacles within rectangular-block-shaped chambers were proposed and the dynamic mixing between the plasma and blood were studied using the level set method coupled with heat transfer. Enhancement of mixing between blood and plasma in the presence of obstacles was demonstrated. Continuous tracking of fluid mixing with determination of temperature distributions was enabled by the present model, which would be a useful tool for future development of cold plasma devices for treatment of blood-related diseases such as leukemia.