Effect of non-thermal plasma (NTP) on bio-particles has been studied using Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and bacteriophages. NTP has been used, and states of different biological components were monitored during the course of the exposure. Analysis of green fluorescent protein (GFP), introduced into E.coli cells proved that NTP causes a prominent protein damages without cutting peptide bonds. We have developed a biological assay which evaluates in vivo DNA damage of the bacteriophages. Different doses of the plasma were applied to wet state of λ phages. From the plasma-exposed λ phages, DNA was purified and subjected to in vitro DNA packaging reactions. The re-packaged phages consist of the DNA from discharged phages and brand-new coat proteins. Survival curves of the re-packaged phages showed extremely large D value (D = 25 s) compared to the previous D value (D = 3 s) from the discharged phages. The results indicate that DNA damage hardly contributed to the inactivation, and the damage in coat proteins is responsible for inactivation of the phages. We also report a single-molecule-based analysis of strand breakages on large DNA molecules induced by the plasma exposure. Single-molecule observation of DNA that involved molecular combing was used to measure the length of individual DNA molecules. The measured DNA length showed that plasma exposure caused a marked change in length of DNA molecules. The rate of plasmainduced strand breakage on large random-coiled DNA molecules was determined using a simple mathematical model. The measured rate shows good relation with the plasma exposure time, and could be used for safety evaluation of the plasma treated water.

We report the kinetic analysis of radicals on fungal spores of Penicillium digitatum interacted with charged-neutral oxygen species (O*) generated plasma discharge using real time in situ electron spin resonance (ESR) measurements. The ESR signal from the spores was observed at a g-value of around 2.004 with a line width of approximately 5G. We have successfully obtained information regarding the reaction mechanism with free radicals and realtime in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens

We have investigated the nonthermal bioplasma sources and their characteristics as well as their interactions with biological cells. The electron temperature and plasma density are measured to be about 1.5 eV and 3×1012 cm-3 , respectively, for the direct palsma jet under Ar gas flow. The hydroxyl radical density has also been investigated and measured to be maximum value of about 3 ×1015 cm-3 and 8 ×1014 cm-3 in the direct plasma jet and dielectric barrier discharge bioplasma, respectively, by the ultraviolet optical absorption spectroscopy. Herein, we have investigated the basic interactions of these nonthermal bioplasma with the living organisms in morphological and biomolecular aspects. We found that the secondary electron emision coefficient of the biological surface has been drastically increased by atmospheric bioplasma, which indicates the biological surface to be oxidized especially by the hydroxyl (OH) radical species. In order to elucidate the basic mechanisms for the cell shrinking and apoptosis leading to a cell death by the nonthermal bioplasma, the cell membrane potential has been estimated based on the ROS density as well as cell capacitances. It is also found that the molecular electron energy band structure in the biological cells have been shifted closer toward the vacuum surface and accordingly their central energy of molecular band becomes small by the nonthermal bioplasma due to cell oxidation caused by OH radicals.

Non thermal plasma is emerging as a novel tool for the treatment of living tissues for biological and medical purpose. In this study we described the effect of DBD (dielectric barrier discharge) plasma on both cancer and normal cell line in presence of osmolytes. Osmolytes having unique protective metabolic roles and also found in animal body, they are acting as antioxidants, providing redox balance, detoxifying sulfide, protect macromolecules, enhance protein folding and regulate cell volume. Based on these interesting properties of osmolytes, non thermal plasma in presence of osmolytes appears to provide a new outlook. Results of this study reveals that osmolytes in presence of plasma act as protecting agent for normal cells however, not to cancer cells in the presence of plasma. The main goal of this study is to protect normal cells from the toxic effect of DBD plasma.

Synthetic biodegradable polymers are commonly used as scaffolds for tissue engineering despite their poor cell adhesion compared to natural polymers. One of the problems in using biodegradable scaffolds is that a higher cell colonization at the scaffold periphery and inadequate colonization at its center is generally noted. Such aspects could seriously compromise the in vivo regeneration of a damaged tissue and, in turn, the success of the implant. Plasma processes have been lately proven as promising scaffold modification techniques. The current work aims at enhancing cell colonization in the core of polymer scaffolds via plasma deposition of coatings with different chemical characteristics. The versatility and ability of plasma processes to modify only the outermost layer of a material can render them competitive with respect to wet chemistry approaches in the field of biomedical materials. In this paper some of the results obtained by plasma processing of 3D interconnected porous polymer scaffolds for Tissue Engineering will be shown. In particular, it will be shown how it is possible to enhance cell adhesion, growth and colonization in porous Polycaprolactone (PCL) scaffolds where gradient of surface compositions are induced from the external (e.g., hydrophobic, slightly cell-repulsive) to the internal (e.g., hydrophilic, cell-adhesive) side of the scaffolds. 3D scaffolds were modified with several RF (13.56 MHz) deposition and treatment plasma processes. Materials were characterized by means of XPS, and FT-IR techniques. Cell-growth experiments were run with cell-lines to check the efficiency of several treatments to enhance/accelerate cell in-growth inside scaffolds.

Emission spectroscopy analysis was used to study the microplasma phenomena. The microplasma discharge in Ar, N2/Ar and O2/Ar was analyzed in the discharge gap area and spatial distribution of active species was measured also outside the electrodes. Spatial and temporal distribution showed the propagation of light emission from anode towards cathode within a time period of 190 ns. The measurement of OH peak at 308.9 nm proved the existence of this excited species 1 mm outside the electrodes area.

In several recent communications from these laboratories, we have described observations that thin organic layers which are rich in primary amine (R-NH2) groups are very efficient surfaces for the adhesion of mammalian cells, even for controlling the differentiation of stem cells. We prepare such deposits by plasma polymerization at low pressure (thin films designated “L-PPE:N”, for “Low-pressure Plasma Polymerized Ethylene containing Nitrogen”), at atmospheric (“High”) pressure (“H-PPE:N”), or by vacuum-ultraviolet photo-polymerization (“UV-PE:N”). More recently, we have also investigated a commercially available material, Parylene diX AM.

In the present communication we shall, first, briefly introduce literature relating to electrostatic interactions between cells, proteins, and charged surfaces. Next, we discuss the comparative results of physico-chemical characterizations of the various organic deposits mentioned above, which deliberately contain varying concentrations of nitrogen, [N], and amine groups, [NH2]. Finally, we present certain selected cell-response results that pertain to applications in orthopedic medicine; we discuss the influence of surface properties on the observed behaviors of various cell lines, with particular emphasis on possible electrostatic attractive forces due to positively charged R-NH3+ groups and negatively charged proteins and cells, respectively.

Cells positioned at the bottom of a Petri dish were exposed, in a home-made plasma source, to pulsed Dielectric Barrier Discharges operated in air in order to investigate the effect of the plasma species on their viability and growth. Processes with different number of pulse, respectively 1,3,9 and 27 pulse, were performed to study the influence on viability and cell growth of two different cell lines, Saos 2 and NHDF. Atmospheric air discharges applied on the two selected cell lines have shown an effect strongly dependent on cell type. At certain doses we have measured increased activity of the NHDF fibroblasts cell line. On the other side, an inhibition of cell adhesion and growth on the Saos 2 osteoblastoma cell line, directly dependent on the plasma doses, was clear. This study shows that by properly tuning the dose of exposure of cells to air plasma it is possible to induce both positive and negative effects on cell growth, that would be useful in several branches of Medicine.

The aim of this review is to introduce the adverse health effects of indium compounds. This review consists of 2 parts: (1) a study of the toxic effects in indium compounds in humans, and (2) a study of the toxic effects of indium tin oxide (ITO) and copper indium gallium diselenide (CIGS) in animals.

To date, 4 epidemiological surveys have been conducted of indium-handling workers in Japan, and all who were studied showed that exposure to indium compounds caused pulmonary interstitial and emphysematous changes. There were clear dose-response and dose-effect relationships between the serum indium levels and the levels of Krebs von den Lungen-6 (KL-6), which is a serological indicator of interstitial pneumonia up until 2011, 8 cases of interstitial pneumonia in Japanese indium-exposed workers, 2 cases of pulmonary alveolar proteinosis (PAP) in US indium-exposed workers, and 1 case of PAP in a Chinese indium-exposed worker have been reported.

In animals studies, it has been clearly demonstrated that ITO and CIGS particles cause pulmonary toxicity and that the dissolution of ITO and CIGS particles in the lungs is considerably slow when repeated intratracheal instillations were given to experimental animals.

Thus, more studies are needed on the effects of human exposure to indium compounds.

Atmospheric microplasma has been intensively studied for various application fields, since this technology has features shown here: generated around only 1 kV under atmospheric pressure,discharge gap of only 10 to 100mm,dielectric barrier discharge. Low discharge voltage atmospheric plasma processis an economical and effective solution forvarious applications such as indoor air control including sterilization, odor removal, surface treatment, and would be suitable for plasma-life science field such as medical application.

In thispaper, the basic study for plasma-life science will be presented. One life science application of microplasma is “sterilization”. The sterilization process was carried out with active species generated between themicroplasmaelectrodes.The active species were observed by emission spectrometry. The spectra showed the existence of active species, and the microplasma had typical characteristics of non-thermal plasma. Sterilization of E. coli was confirmed after microplasma treatment with Ar gas. The bacteria shape was changed after the microplasma process. The other application is “Surface treatment” by long life active species of materials which used for the medical field. The targets are glass, polymer film and others could be also possible.

The process is known as remote microplasma sterilization method. Microplasma generated by both air and Ar are effective for sterilization. Observation by the SEM images shows the E. coli had a shrunked shape after the microplasma treatment.

The contact angle of a water droplet on the polymer surface was measured to estimate its hydrophilicity. The relation between the contact angle and treatment time was investigated. Contact angle decreased from 75.6° to 45.6° after 10 s of treatment.

The gold nanoparticles (AuNPs) conjugated with carbon nanotubes (CNTs) and/or biomolecules such as DNA are synthesized using a novel plasma technique combined with introduction of ionic liquids or aqueous solution for application to life sciences.

First, we successfully generate the gas-liquid interfacial discharge plasma (GLIDP) using an ionic liquid, in which the large sheath electric field is formed on the ionic liquid and the plasma ion irradiation to the ionic liquid with high energy is realized.

Second, it is found that the high energy ion irradiation to the ionic liquid is effective for the synthesis of the AuNPs. Furthermore, the controlled ion irradiation to the ionic liquid including a carboxyl group can realize the density-controlled synthesis of the AuNPs on the CNTs by dissociation of the ionic liquid and the controlled functionalization of the CNTs by the dissociated carboxyl group.

Third, the size- and morphology-controlled AuNPs covered with DNA are synthesized using the GLIDP with aqueous solution, where DNA prevents the AuNPs from further clustering, resulting in the small-sized AuNPs. The synthesized AuNPs conjugated with DNA can be encapsulated into the CNTs using the DC electric field. The CNTs work as vectors to deliver DNA into living cells because the CNTs have the unique ability to easily penetrate cell membranes with low cytotoxicity.

Growth enhancement characteristics of plants are investigated using an atmospheric discharge plasma. Atmospheric pressure plasma torch is consisted of alumina ceramics tube and the steel mesh electrodes wound inside and outside of the tube. The growth enhancement was observed in the length of stem and root of plants after the plasma irradiation to seeds. The stem length increases approximately 2.8 times after the cultivation time of 24 h. And the effect is found to be maintained for 40 h, after sowing seeds. The mechanism of the growth enhancement would be the redox reaction inside plant cells induced by oxygen radicals.

Two independent ovarian cancer cell lines and fibroblast controls were treated with nonequilibrium atmospheric pressure plasma (NEAPP). Most ovarian cancer cells were detached from the culture dish by continuous plasma treatment to a single spot on the dish. Next, the plasma source was applied over the whole dish using a robot arm. In vitro cell proliferation assays showed that plasma treatments significantly decreased proliferation rates of ovarian cancer cells compared to fibroblast cells. FACS and Western blot analysis showed that plasma treatment of ovarian cancer cells induced apoptosis. NEAPP could be a promising tool for therapy for ovarian cancers.

We compared growth enhancement of radish induced by O2, air, and Ar plasma irradiation. The average length of radish sprouts cultivated for 4 days after O2 plasma irradiation is 70% longer than that of sprouts without irradiation. The O2 plasma irradiation is more effective in enhancing growth than air and Ar radio frequency plasma irradiation. Cell morphology and cell size of sprouts with O2 plasma irradiation is nearly the same as those without irradiation. These results suggest that plasma induced acceleration of cell proliferation brings about the rapid growth.

Polymeric materials have been attracted the attention of researchers in various R&D applications. In this research, attempts were made to evaluate the changes in blood compatibility of polyethylene terephthalate (PET) by grafting acrylic acid (AAc) and immobilizing heparin by employing two-step plasma treatment. The PET surface was modified by using a novel method named “two-step plasma treatments” (TSPT). While first plasma is creating active sites for grafting, the second plasma polymerizing pre-adsorbed reactive monomer onto the surface of films. Finally, heparin immobilization was performed in the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide. All films were characterized by attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM). The surface hydrophilicity of films was studied by water contact angle test and blood compatibility evaluated by Lactate dehydrogenase method (LDH Test). In vitro studies based on LDH results demonstrared that platelet adhesion onto the modified surfaces with heparin was drastically reduced in comparison with unmodified PET.

We develop a plasma processing technique for modifying the surface properties of micro- and nanostructured materials for biomedical applications. We also investigate the physical and chemical roles of the plasma in modifying the surfaces of micro- and nanostructured materials such as magnetic nanoparticles (MNPs), carbon nanotubes (CNTs), nanophosphors, and biomolecules for various biomedical applications. We introduced amino groups onto the surfaces of graphite-encapsulated iron compound nanoparticles using a low-pressure Ar plasma pre-treatment and ammonia plasma post-treatment followed by immobilization of biomolecules, such as dextran and N-acetyllactosamine (LacNAc). The present technique was also used to introduce amino groups onto CNT dot arrays grown on Si substrates for use in biochip sensors.

Using a N2 gas plasma apparatus (BLP-TES, NGK Insulators, Ltd), we showed that N2 gas plasma treatment of influenza A virus caused degradation of viral nucleoproteins. These findings suggest that N2 gas plasma treatment may contribute to infection prevention control for influenza.

We investigated effects of atmospheric pressure dielectric barrier discharge (DBD) plasma irradiation on growth characteristics of bread yeast (Saccharomyces cerevisie). Nitric oxide of 400 ppm and O3 above 200 ppm are produce by the DBD plasmas. DBD plasma irradiation of 50 and 100 s enhances the growth of yeast in the lag phase, whereas 150 s irradiation suppresses the growth. There is an optimum duration of plasma irradiation for the growth promotion.

A high-density non-equilibrium atmospheric pressure plasma (NEAPP) applied for inactivating fungal spores of P. digitatum is introduced as an environmentally safe and rapid-inactivation method. The contributions of ozone, ultra violet (UV) radiation and ground-state atomic oxygen in the NEAPP on the inactivation of the spores are evaluated using colony count method.

The absolute densities of ozone were measured by using ultraviolet absorption spectroscopy. The ozone density increased from 2 to 8 ppm with an increase in the distance from the plasma source, while the inactivation rate decreased. The inactivation rate of plasma was evaluated to be thousand times higher than that of an ozone generator using the integrated number density of ozone. In addition, it was clarified that the contribution of UV radiation to inactivation was not dominant for P. digitatum inactivation by NEAPP by filtering the active species using quartz plate. From these results, we can speculate that the inactivation efficiency of reactive oxygen species (ROS) will be larger than those of others.

In order to investigate the effect of ground-state atomic oxygen as one of ROS, the inactivation of P. digitatum spores using an oxygen radical source that employs a high-density atmospheric-pressure O2/Ar plasma. The absolute O density was measured to be 1.4×1014 and 1.5×1015 cm–3 using vacuum ultra violet absorption spectroscopy (VUVAS) using a microdischarge hollow cathode lamp. The behaviors of the O densities as a function of O2/(Ar+O2) mixture flow rate ratio correspond to that of the inactivation rate. This result indicates that ground-state atomic oxygen is concluded to be the dominant species that causes inactivation.