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Herein, we present a new route to synthesize poly(2-oxazoline)s (POx) with coumarin moieties as pendant groups that can be crosslinked by irradiation to form hydrogels. The synthesis of a novel coumarin-containing 2-oxazoline monomer, 2-[(4-methyl-7-coumarinyloxy)methyl]oxazoline is described in four steps and further its subsequent homo- and copolymerization with 2-ethyl-2-oxazoline (EtOx) via cationic ring-opening polymerization (CROP). The received polymers with different coumarin content (8, 4 and 2 mol%) were compared with a known copolymer synthesized via postpolymerization modification of partially hydrolyzed poly(2-ethyl-2-oxazoline) (PEtOx) with a coumarin derivative. The thermoresponsive behavior of the POx in aqueous solutions was investigated, showing a clear difference in the cloud point temperature (Tcp) between the polymers synthesized via different strategies. The hydrogel formation was achieved by irradiation with UV light by the following two methods: on the one hand with the pure coumarin-containing POx and on the other hand mixed with poly(ethylene glycol) diacrylate (PEGDA). The obtained hydrogels were compared regarding their swelling degree and their gel content, whereas the swelling degree in water of prepared hydrogels can be tuned by using POx by varying the coumarin content. Graphical abstract

Macroporous polymer monoliths prepared from high internal phase emulsions (HIPEs) can be found in various biomedical applications. While typically water-in-oil HIPEs are applied for polyHIPE preparation, they are not suitable for hydrophilic polyHIPE preparation. Herein, direct oil-in-water emulsions based on water-soluble poly(ethylene glycol)diacrylate or poly(ethylene glycol)dimethacrylate were developed. Furthermore, the incorporation of a hydrophilic water-miscible thiol, ethoxylated trimethylolpropane tris(3-mercaptopropionate) (ETTMP) was reported for the first time within thiol−ene polyHIPEs. Due to the transparency of the emulsions, rapid curing via photopolymerization was feasible. The average pore diameters of the resulting polyHIPEs ranged between 1.2 and 3.6 μm, and porosity of up to 90% was achieved. The water uptake of the materials reached up to 1000% by weight. Drug loading and release were demonstrated, employing salicylic acid as a model drug. Porous profile and biodegradability add to the usefulness of the material for biomedical applications.

Seed modification by atmospheric pressure non-thermal plasma treatment was tested on pine species. The Diffuse Coplanar Surface Barrier Discharge (DCSBD) with expose times of 0 s, 1 s, 3 s, 5 s, 10 s, 30 s, 60 s was used on seed treatment of Pinus sylvestris, Pinus nigra and Pinus mugo. The effect of plasma treatment on the chemical bonds on the seed surface was studied using the Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Characteristics of seed germination and early growth were measured. ATR-FTIR surface diagnostics did not show any damage. Changes in the peak intensities indicated the presence of oxygen and nitrogen-containing groups, or a reduction of the lipid layer on the surface. Various statistically significant effects of the three species of seeds treated with DCSBD treatment were recorded. No significant differences were found between control sample and plasma treated ones, but some positive trends were obtained. Positive trends were recorded in germinated and growing seeds of all three species mainly after 3 s exposures. Exposure times from 10 s had an inhibitory effect. Based on the results obtained, it can be recommended that forest nurseries performance of nonthermal plasma modification of seeds should be evaluated to measure the durability of the observed growth characteristics.

Cold atmospheric pressure plasma treatment is currently being explored as an alternative way to improve the germination and growing parameters of plant seeds. However, it is important to pay attention to the effect of plasma treatment on DNA damage of the seeds as well as detailed characteristics of plasma composition and parameters. The aim of this work was to study the DNA damage of plasma-treated pea seeds (Pisum sativum L.) and plasma parameters such as the chemical composition of plasma gaseous compounds and plasma radiation. Seeds were treated with plasma using the diffuse coplanar surface barrier discharge generated in different working gases (ambient air, nitrogen, oxygen and different mixtures of oxygen and nitrogen) at atmospheric pressure and at 60 s, 180 s and 300 s exposure times. DNA damage was studied using the single cell-gel electrophoresis called the comet assay and the plasma parameters were investigated by Fourier transform infrared spectroscopy and optical emission spectroscopy. Experiments in different ratios of oxygen and nitrogen were realized in order to understand the reaction mechanism between the ambient air plasma and the treated seeds. Based on our results, ambient air plasma appears to be the most advantageous for the plasma treatment due to no significant DNA damage because of the proper combination of plasma composition in combination with water vapor present in ambient air.

Aspergillus ochraceus is a soil fungus known to produce ochratoxin A, a harmful secondary metabolite. Prevention and control of fungal pathogens mostly rely on chemical fungicides, which is one of the contributing factors in the emergence of the fungal resistance, hence novel methods for fungal eradication have been extensively researched. The cold atmospheric pressure (CAP) plasma generated in ambient air has been recently applied in microbial decontamination. Here we used the diffuse coplanar surface barrier discharge in inactivation of a toxigenic strain A. ochraceus. The plasma-treated conidia and mycelium exhibited morphological changes such as ruptures and desiccation. Mycelium dehydration and changes in the chemical composition of hyphal surface accompanied plasma treatment. The growth of 26 h old mycelia were significantly restricted after 30 s of plasma treatment. The conidial vitality declined 4 logs after 180 s of plasma exposure leading to almost complete decontamination. After shorter plasma treatment of conidia, the ochratoxin A (OTA) production increased at the early stage of cultivation, but the overall level was significantly reduced compared to untreated samples after longer cultivation. Our results indicated that the fungal growth and the OTA production were significantly changed by plasma treatment and underscored CAP plasma as a promising method in the decontamination of A. ochraceus without a risk to generate strains with increased OTA production.

The effect of low-temperature plasma generated at atmospheric pressure was studied in term of reduction of bacterial contamination and influence on nutritional characteristics of allspice (Pimenta dioica). The low-temperature plasma was generated in ambient air using Diffuse Coplanar Surface Barrier Discharge (DCSBD). The bacterial species inoculated on the surface of samples were reduced in dependence on exposure time. Plasma treatment time of 240 s led to log10 CFU/g of Salmonella Enteritidis to below detection level (1.0 log10 CFU/g) from initial population of 7.64 log10 CFU/g. After treatment with DCSBD plasma for 300 s, the populations of Bacillus subtilis and Bacillus subtilis endospores were decreased by 2.85 log10 CFU/g and 1.70 log10 CFU/g, respectively. The parameters related to the decontamination effect were measured. Temperature of samples does not exceed the value declared as low-temperature limit and water activity decreased after plasma treatment. The effect of plasma on the qualitative properties of allspice studied by infrared spectroscopy showed no changes in characteristic chemical bonds on the surface and also inside the samples. Measurements of polyphenolics content in allspice showed that plasma has negligible impact on these main constituents affecting taste and flavor. The experiments demonstrated an efficient reduction in microbial contamination and minimal influence on the aroma profile of treated and stored spice.

Great attention is currently being paid to the application of non-thermal plasma in agriculture. Seed germination is the first and critical time in the life cycle of each plant. Cold atmospheric pressure plasma (CAPP) generated by Diffuse Coplanar Surface Barrier Discharge, working at atmospheric pressure in ambient air, oxygen or nitrogen atmosphere in different time applications (60, 180, 300 s) was used to investigate its influence on early stages of germination processes in pea (Pisum sativum L. cv. Prophet). For evaluation of physiological parameters germination, the imbibition rate, percentage of germination, germination potential, germination index, seeds and seedlings vitality index, and seedlings length index were determined. In this work, also CAPP influence on dehydrogenases and lytic enzymes (amylase, glucanase and protease) as well as genotoxic effects were studied. Infrared spectra of pea seeds surface demonstrate that reactive oxygen and nitrogen species as well as UV radiation produced in plasma cause oxidation of lipids and polysaccharides on the surface of samples and lead to increase of wettability related to increased imbibition which can accelerate germination. A significant positive effect had mainly CAPP generated in air and nitrogen atmosphere at treatment time of 60 s on the studied germination and growth parameters and overall activation of lytic enzymes in pea seeds compared to untreated control. Increased concentrations of radicals in young 3-day old seedlings and activation of antioxidant enzymes suggest that low plasma doses act as low stress, which paradoxically has a stimulating effect on germination, growth and development of seedlings.

In order to reduce the environmental burden of chemicals, various new alternatives to seed protection are being sought. Our aim was to find an environmentally acceptable solution leading to the inactivation of seed-borne phytopathogenic fungi Fusarium culmorum on the surface of wheat and barley seeds with a positive effect on their germination. As a low-temperature plasma (LTP) source, a Diffuse Coplanar Surface Barrier Discharge (DCSBD) was used. Plasma generated by DCSBD is non-equilibrium, cold, diffuse, macroscopically homogeneous even in ambient air at atmospheric pressure. Experimental results showed that LTP treatment in the range of 120—300 s significantly inhibits the growth of F. culmorum on the surface of the seeds. The efficiency of LTP treatment was compared with traditional seed protection processes using chemical fungicide and also with combined seed pretreatment by plasma and subsequent application of chemical fungicide. No growth of F. culmorum was observed after the combination of Vitavax 2000 fungicide application in the dose of 10 % and 60 s of LTP treatment even on the 5th day of incubation. Better wettability of seeds with the chemical fungicide was related to the change on seed surface, which becomes hydrophilic after 10 s of LTP application. Short LTP exposure times did not affect germination and improved the growth parameter of cereal seeds. By combining physical (LTP) and chemical (Vitavax 2000) treatments of cereal seeds, it is possible to effectively reduce the required amount of chemical fungicide and to stimulate germination and early growth seed parameters.

We studied the effects of nonthermal plasma (NTP) treatment on various parameters of early germination stages of Pinus nigra seeds. In the experiment, the diffuse coplanar surface barrier discharge (DCSBD) with treatment time periods of 0, 1, 3, 5, 10, 30, and 60 s was used. Changes on the plasma-treated seed surface were studied by attenuated total reflectance-Fourier transform infrared spectroscopy. Seed germination, germination rate, germination index, length of seedling, dry seedling weight, and seedling vigor index I and II were determined in a growth test under laboratory conditions. Various statistically significant effects of seed exposure to DCSBD plasma treatment were recorded. A positive reaction was observed in the germinated seeds after exposure for 1- and 5-s. Longer exposure time periods had a rather inhibitory effect. The performance of forest nurseries of NTP modification of seeds should be evaluated in order to measure the durability of the observed growth characteristics. The potential of NTP treatment on seeds in plant ecology in future is highlighted.

Thermoresponsive polymers play an important role in designing drug delivery systems for biomedical applications. In this contribution, the effect of encapsulated hydrophobic drug dexamethasone on thermoresponsive behavior of diblock copolymers was studied. A small series of diblock copoly(2-oxazoline)s was prepared by combining thermoresponsive 2-n-propyl-2-oxazoline (nPrOx) and hydrophilic 2-methyl-2-oxazoline (MeOx) in two ratios and two polymer chain lengths. The addition of dexamethasone affected the thermoresponsive behavior of one of the copolymers, nPrOx20-MeOx180, in the aqueous medium by shifting the cloud point temperature to lower values. In addition, the formation of microparticles containing dexamethasone was observed during the heating of the samples. The morphology and number of microparticles were affected by the structure and concentration of copolymer, the drug concentration, and the temperature. The crystalline nature of formed microparticles was confirmed by polarized light microscopy, confocal Raman microscopy, and wide-angle X-ray scattering. The results demonstrate the importance of studying drug/polymer interactions for the future development of thermoresponsive drug carriers.

For many decades, poly(2-oxazoline)s and poly(2-oxazine)s, two closely related families of polymers, have led the life of a rather obscure research topic with only a few research groups world-wide working with them. This has changed in the last five to ten years, presumably triggered significantly by very promising clinical trials of the first poly(2-oxazoline)-based drug conjugate. The huge chemical and structural toolbox poly(2-oxazoline)s and poly(2-oxazine)s has been extended very significantly in the last few years, but their potential still remains largely untapped. Here, specifically, the developments in macromolecular self-assemblies and non-covalent drug delivery systems such as polyplexes and drug nanoformulations based on poly(2-oxazoline)s and poly(2-oxazine)s are reviewed. This highly dynamic field benefits particularly from the extensive synthetic toolbox poly(2-oxazoline)s and poly(2-oxazine)s offer and also may have the largest potential for a further development. It is expected that the research dynamics will remain high in the next few years, particularly as more about the safety and therapeutic potential of poly(2-oxazoline)s and poly(2-oxazine)s is learned.

This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light, 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.

Modification of thermogelling biodegradable copolymers with functional groups enables further covalent crosslinking of physical micelle-based hydrogels formed at specific temperature in water. The resulting hybrid hydrogel network exhibits an increase in stiffness and degradation stability. In this work, synthesized well-defined thermoresponsive alpha,omega-itaconyl-poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) (alpha,omega-itaconyl-PLGA-PEG-PLGA) macromonomers with a high degree of itaconyl-substitution providing free double bonds are photocrosslinked in water at both 25 and 37 degrees C using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LiTPO) acting as water-soluble non-toxic photoinitiator. The effect of LiTPO on the thixotropic behavior of macromonomer in water at 25 degrees C without irradiation is evaluated. With the addition of a low amount of the photoinitiator (0.1 wt%), the degree of copolymer thixotropy increases. However, further increase in the photoinitiator concentration (0.5-3 wt%) leads to a lower degree of thixotropy. The photoinitiator is presumably interfering with the micellar self-assembly of the copolymer. This trend is also reflected in photocrosslinking efficiency, where the hybrid hydrogel networks with the highest storage moduli are achieved with very low concentrations of the photoinitiator (0.1 wt%) at 25 degrees C, while this trend is reversed at 37 degrees C. The hydrolytic stability of hydrogels prepared at 37 degrees C from 17 wt% macromonomer solution with 1% LiTPO exceeds 22 days. Modifikace termosenzitivních biodegradabilních kopolymerů s funkčními skupinami umožňuje další kovalentní zesíťování fyzikálních hydrogelů na bázi micel vytvořených ve vodě při specifické teplotě. Výsledná hybridní hydrogelová síť vykazuje zvýšení tuhosti a degradační stability. V této práci byly syntetizováné dobře definované termoresponzivní , itaconylPLGAPEGPLGA) makromonomery s vysokým stupněm substituce kyseliny itakonové s volnými dvojnými vazbami, které byly fotosíťovány ve vodě při 25 i 37 ° C v přítonosti ve vodě rozpustného netoxického fotoiniciátoru lithium-fenyl 2,4,6-trimethylbenzoylfosfinátu (LiTPO).

The aim of this study was to use diffuse coplanar surface barrier discharge (DCSBD) non-thermal plasma for the disinfection of pine seed surfaces infected with Fusarium oxysporum spores. Artificially infected seeds of Scots pine (Pinus sylvestris L.) were treated with plasma for the following exposure times: 1 s, 3 s, 5 s, 10 s, 15 s, 20 s, 30 s, and 60 s, and subsequently germinated on agar medium in Petri dishes at room temperature for the estimation of seed germination and disinfection effect of plasma treatment. Results of the treated samples were compared to the control samples, which were prepared as follows: seeds uninfected and non-treated with plasma (first control), seeds infected with F. oxysporum and non-treated with plasma (second control), and seeds infected with F. oxysporum, non-treated with plasma, but sterilized with 30% perhydrol (third control). Obtained results indicate that 3 s plasma treatment was an optimal time to inhibit the F. oxysporum growth, and at the same time, increase the seed germination level. In addition, our results are the first to show the practical application of non-thermal plasma in disinfecting infected Scots pine seeds and improving their germination. According to the results of this study, non-thermal plasma can serve as a seed surface disinfectant in the regeneration system of different pine species.

Poly(2-oxazolines) (POx) are an attractive material of choice for biocompatible and bioactive coatings in medical applications. To prepare POx coatings, the plasma polymerization represents a fast and facile approach that is surface-independent. However, unfavorable factors of this method such as using the low-pressure regimes and noble gases, or poor control over the resulting surface chemistry limit its utilization. Here, we propose to overcome these drawbacks by using well-defined POx-based copolymers prepared by living cationic polymerization as a starting material. Chemically inert polytetrafluoroethylene (PTFE) is selected as a substrate due to its beneficial features for medical applications. The deposited POx layer is additionally post-treated by non-equilibrium plasma generated at atmospheric pressure. For this purpose, diffuse coplanar surface barrier discharge (DCSBD) is used as a source of “cold” homogeneous plasma, as it is operating at atmospheric pressure even in ambient air. Prepared POx coatings possess hydrophilic nature with an achieved water contact angle of 60°, which is noticeably lower in comparison to the initial value of 106° for raw PTFE. Moreover, the increased fibroblasts adhesion in comparison to raw PTFE is achieved, and the physical and biological properties of the POx-modified surfaces remain stable for 30 days.

Inorganic submicron fibers (ISF) are nowadays widely studied material. Usually, they are produced by 2-step process. First, the composite metal-organic fibers are produced from polymer matrix and metallic precursor, typically alkoxides or salts by standard spinning techniques. After this, prepared composite fibers are thermally calcinated to remove polymer and form ceramic fibers. In this study, we used low temperature plasma generated at atmospheric pressure using Diffuse Coplanar Surface Barrier Discharge (DCSBD) to eliminate organics from the composite fibers before thermal treatment to reduce the time required for thermal calcination of Al2O3 fibers. This plasma pre-treatment enables using significantly higher heating rates compared to standard calcination without damaging the fiber structure.

The objective of the study was the evaluation of the efficacy of plasma activated water (PAW) for Escherichia coli inoculated on soybean seed surface. PAW was prepared by high-power atmospheric pressure air plasma jet. The inactivation kinetics, explained by Bigelow log-linear and Weibull models, showed the significant antibacterial potential of PAW in comparison to the control (sterile distilled water). PAW treatment for 25 min let to log10 CFU/g reduction of E. coli from 6.8 to 3.6 and its antibacterial effect persisted further 44 h (2.7 log10 CFU/g). Decimal reduction time (D-value) for tested bacteria was 7 min. Furthermore, the influence on PAW on the polyphenolics content and antioxidant activity was evaluated. To identify the PAW chemistry, physical properties, including pH, redox potential, and conductivity were estimated. The levels of H2O2, nitrate (NO3−) and nitrite anions (NO2−) as long-lived species were measured and compared to SDW without plasma activation.

This study investigated the effect of cold atmospheric pressure air plasma pre-treatment on pea (Pisum sativum L.) seeds. The aim of our study was to verify the plasma impact on DNA damage and the induction of positive adaptive response in pea seedlings. The pea seeds were treated by plasma at the exposure times ranging from 60 to 300 s. Plasma was generated using the coplanar type of dielectric surface barrier discharge. The main plasma properties were estimated by electrical and by optical emission spectroscopy measurements. The DNA damage was evaluated by the alkaline comet assay. The adaptive response on seedlings was tested using the toxic concentration of zeocin. The positive effect of plasma pre-treatment and the reduction of DNA damage of pea seedlings in comparison to control samples without plasma was observed at all exposure times used. The strongest repairing effect was observed at the plasma treatment time in the range from 120 to 240 s. These results verify the safety of plasma application in agriculture at germination and growth enhancement and the existence of a plasma induced adaptive response.

Among external stimuli used to trigger release of a drug from a polymeric carrier, ultrasound has gained increasing attention due to its non-invasive nature, safety and low cost. Despite this attention, there is only limited knowledge about how materials available for the preparation of drug carriers respond to ultrasound. This study investigates the effect of ultrasound on the release of a hydrophobic drug, dexamethasone, from poly(2-oxazoline)-based micelles. Spontaneous and ultrasound-mediated release of dexamethasone from five types of micelles made of poly(2-oxazoline) block copolymers, composed of hydrophilic poly(2-methyl-2-oxazoline) and hydrophobic poly(2-n-propyl-2-oxazoline) or poly(2-butyl-2-oxazoline-co-2-(3-butenyl)-2-oxazoline), was studied. The release profiles were fitted by zero-order and Ritger-Peppas models. The ultrasound increased the amount of released dexamethasone by 6% to 105% depending on the type of copolymer, the amount of loaded dexamethasone, and the stimulation time point. This study investigates for the first time the interaction between different poly(2-oxazoline)-based micelle formulations and ultrasound waves, quantifying the efficacy of such stimulation in modulating dexamethasone release from these nanocarriers.

Cold atmospheric pressure ambient air plasma generated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) was investigated for inhibition of native microbiota and potentially dangerous pathogens (Aspergillus flavus, Alternaria alternata and Fusarium culmorum) on the maize surface. Moreover, the improvement of germination and growth parameters of maize seeds was evaluated. Maize (Zea mays L.; cv. Ronaldinio), one of the most important cultivated crops worldwide, was selected as the research material. Electrical measurements confirmed the high volume power density (80 W cm−3) of DCSBD plasma. Non-equilibrium plasma state evaluated using optical emission spectroscopy showed values of vibrational and rotational temperature (2700 ± 300) K and (370 ± 75) K, respectively. Changes on the plasma treated seeds surface were studied by water contact angle measurement, scanning electron microscope analysis and Fourier transform infrared spectroscopy. A complete devitalisation of native microbiota on the surface of seeds was observed after a short treatment time of 60 s (bacteria) and 180 s (filamentous fungi). The plasma treatment efficiency of artificially contaminated maize seeds was estimated as a reduction of 3.79 log (CFU/g) in F. culmorum after a 60-s plasma treatment, 4.21 log (CFU/g) in A. flavus and 3.22 log (CFU/g) in A. alternata after a 300-s plasma treatment. Moreover, the obtained results show an increase in wettability, resulting in a better water uptake and in an enhancement of growth parameters. The investigated DCSBD plasma source provides significant technical advantages and application potential for seed surface finishing without the use of hazardous chemicals.

Atmospheric pressure plasma assisted calcination by the preparation of TiO2 submicron fibers as a low-temperature alternative to the conventional thermal annealing was studied. A special type of dielectric barrier discharge was used for plasma treatment of hybrid titanium butoxide/polyvinylpyrrolidone (Ti(Bu)/PVP) fibers prepared by forcespinning to decompose and oxidize the base polymer and precursor. The obtained fibers were characterized by changes in chemical bonds on the surface using Fourier Transform Infrared Spectroscopy (FTIR), chemical composition by using Energy-Dispersive X-Ray Spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS). The morphology of fibers was investigated by Scanning Electron Microscopy (SEM). A significant decrease of organic components was reached by short plasma exposure times less than 1 h. The obtained fibers exhibit a high surface porosity without degradation of the fibrous structure. The results obtained indicate that atmospheric pressure plasma assisted calcination can be a viable low-temperature, energy-and time-saving alternative or pre-treatment method for the conventional high-temperature thermal calcination.

The pulsed corona discharge (CD) generated in contact with water and directly in water, and high-power air plasma jet (APJ) were studied for production of plasma activated water (PAW). The changes of physical (pH, redox potential, conductivity, temperature) and chemical (peroxides, nitrites, nitrates concentrations) properties of treated water were investigated. The comparison of CD generated in gas/water interface and underwater configuration in the same system showed that the interaction of reactive oxygen and nitrogen species formed in ambient air in gas/water system induces different chemical processes, leading to lower pH, higher oxidation-reduction potential (ORP) and higher conductivity of PAW than in underwater discharge. High yield of peroxide was observed in both configurations. The PAW prepared by APJ exhibits high concentration of nitrites and nitrates according to supplied energy, and related significant decrease of pH and increase of ORP and conductivity after treatment. The antimicrobial effect of PAW prepared by CD and plasma jet on lentils sprouts was studied in different treatment and washing times. The APJ appears to have great efficacy on water activation resulted in strong decontamination effect. The PAW treated by APJ for 10 min led to bacterial reduction from initial 8.3 to 5.9 and 4.0 log10 CFU g−1 after 10 and 30 min of washing, respectively.

Zea mays L. is one of the most produced crops, and there are still parts of the world where maize is the basic staple food. To improve agriculture, mankind always looks for new, better methods of growing crops, especially in the current changing climatic conditions. Cold atmospheric pressure plasma (CAPP) has already showed its potential to enhance the culturing of crops, but it still needs more research for safe implementation into agriculture. In this work, it was shown that short CAPP treatment of maize grains had a positive effect on the vitality of grains and young seedlings, which may be connected to stimulation of antioxidant and lytic enzyme activities by short CAPP treatment. However, the prolonged treatment had a negative impact on the germination, growth, and production indexes. CAPP treatment caused the increased expression of genes for heat shock proteins HSP101 and HSP70 in the first two days after sowing. Using comet assay it was observed that shorter treatment times (30–120 s) did not cause DNA damage. Surface diagnostics of plasma-treated grains showed that plasma increases the hydrophilicity of the surface but does not damage the chemical bonds on the surface.

Research on the subject of smart biomaterials has become a cornerstone of tissue engineering and regenerative medicine. Herein, the authors report on developing magnetic hydrogels that combine high biocompatibility and remarkable activity in magnetic fields. We fabricated magnetic hydrogels based on poly(2-ethyl-2-oxazoline) (POx) via living ring-opening cationic polymerization with in-situ embedding of the carbonyl iron (CI) particles. Investigation was made as to the effect exerted by the concentration of CI on magnetic, viscoelastic/magnetorheological properties, the degree of equilibrium swelling, and cytotoxicity. The hydrogels exhibited an open pore structure, as evidenced by computed tomography (CT) imaging. Susceptibility measurements revealed the concentration-dependent field-induced particle restructuration indicating elongation/contraction of the material, thereby determining the potential for magneto-mechanical stimulation of the cells. The POx-based magnetic hydrogels were amphiphilic in character, showing decrease in their capability to hold liquid alongside increase in CI concentration. Viscoelastic measurements suggested that interaction occurred between the particles and matrix based on inconsistency between the experimental storage modulus and the Krieger–Dougherty model. The synthesized materials exhibited excellent biocompatibility toward the 3T3 fibroblast cell line in tests of extract toxicity and direct contact cytotoxicity (ISO standards). The unique combination of properties exhibited by the material - magneto-mechanical activity and biocompatibility - could prove favorable in fields such as biomedicine and biomechanics.

Minimizing the foreign body reaction to polyimide-based implanted devices plays a pivotal role in several biomedical applications. In this work, we propose materials exhibiting nonbiofouling properties and a Young's modulus reflecting that of soft human tissues. We describe the synthesis, characterization, and in vitro validation of poly(carboxybetaine) hydrogel coatings covalently attached to polyimide substrates via a photolabile 4-azidophenyl group, incorporated in poly(carboxybetaine) chains at two concentrations of 1.6 and 3.1 mol %. The presence of coatings was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy. White light interferometry was used to evaluate the coating continuity and thickness (between 3 and 6 mu m under dry conditions). Confocal laser scanning microscopy allowed us to quantify the thickness of the swollen hydrogel coatings that ranged between 13 and 32 mu m. The different hydrogel formulations resulted in stiffness values ranging from 2 to 19 kPa and led to different fibroblast and macrophage responses in vitro. Both cell types showed a minimum adhesion on the softest hydrogel type. In addition, both the overall macrophage activation and cytotoxicity were observed to be negligible for all of the tested material formulations. These results are a promising starting point toward future advanced implantable systems. In particular, such technology paves the way for novel neural interfaces able to minimize the fibrotic reaction, once implanted in vivo, and to maximize their long-term stability and functionality.

This publication is the result of the project: "Applied research and development of innovative drilling technology for ultra--deep geothermal wells", ITMS code 26240220042, supported by the Rese-arch & Development Operational Pro-gramme funded by the ERDF. This work was supported by the Slovak Research and Development Agency under contract No. APVV-14-0518.

Plasma assisted calcination of composite submicron fibers (Ce(NO3)3/polyvinylpyrrolidone)as a novel method for inorganic submicron fibers preparation was studied. Special type of dielectric barrier discharge, so called Diffuse Coplanar Surface Barrier Discharge(DCSBD)was used for the plasma treatment of composite fibers at atmospheric pressure in ambient air for the purpose of oxidation and removing of organic base polymer by the active species produced in plasma. High decrease of C/Ce ratio and formation of porosity on fibers surface were observed after plasma calcination at exposure time in the order of minutes. Due to the low temperature approach and short treatment time, plasma assisted calcination is a suitable and perspective alternative to the conventional high-temperature calcination.

Non-thermal atmospheric pressure plasmas are known to be an effective method for the inactivation of microorganisms. However, yeasts have proved to be more resistant to provided treatments. We investigated the influence of an Argon plasma jet on the inactivation of four different yeasts; Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida parapsilosis and Magnusiomyces magnusii. Results from direct plasma treatment on the yeasts in distilled water, as the most effective technique we found, are presented here. The surviving yeasts after 5, 7, and 10 min plasma exposures were evaluated visually and quantitatively. Quantitative results showed strong reductions in the survival rates after the plasma treatment. The longest plasma exposure time yielded the least survival. Moreover, how long the inactivations lasted was evaluated by assessing the treated samples after 1 h and again after 2 h. The survival rates were further decreased within these storage times. In the 10 min treated-2 h stored samples, the rates dropped to 5% or even below, depending on the yeast species. High concentrations of reactive oxygen and nitrogen species in the plasma-air-water interacting system were detected by optical emission spectroscopy of the plasma jet and also by measuring concentrations of H2O2, NO2 − and NO3 − in plasma activated water (as the surrounding liquid for the yeasts). The conductivity and pH of the treated water was measured as well. The level of the conductivity increased along with the decrease in pH. Synergistic effects of these chemical reactive species in acidified water resulted in the yeast inactivation.

The cold atmospheric-pressure plasma (CAPP) has become one of the recent effective decontamination technologies, but CAPP interactions with biological material remain the subject of many studies. The CAPP generates numerous types of particles and radiations that synergistically affect cells and tissues differently depending on their structure. In this study, we investigated the effect of CAPP generated by diffuse coplanar surface barrier discharge on hyphae of Aspergillus flavus. Hyphae underwent massive structural changes after plasma treatment. Scanning electron microscopy showed drying hyphae that were forming creases on the hyphal surface. ATR-FTIR analysis demonstrated an increase of signal intensity for C=O and C-O stretching vibrations indicating chemical changes in molecular structures located on hyphal surface. The increase in membrane permeability was detected by the fluorescent dye, propidium iodide. Biomass dry weight determination and increase in permeability indicated leakage of cell content and subsequent death. Disintegration of nuclei and DNA degradation confirmed cell death after plasma treatment. Damage of plasma membrane was related to lipoperoxidation that was determined by higher levels of thiobarbituric acid reactive species after plasma treatment. The CAPP treatment led to rise of intracellular ROS levels detected by fluorescent microscopy using 2',7'-dichlorodihydrofluorescein diacetate. At the same time, antioxidant enzyme activities increased, and level of reduced glutathione decreased. The results in this study indicated that the CAPP treatment in A. flavus targeted both cell surface structures, cell wall, and plasma membrane, inflicting injury on hyphal cells which led to subsequent oxidative stress and finally cell death at higher CAPP doses.

A series of hydrogels from 2-ethyl-2-oxazoline and three bis(2-oxazoline) crosslinkers—1,4-butylene-2,2′-bis(2-oxazoline), 1,6-hexamethylene-2,2′-bis(2-oxazoline), and 1,8-octamethylene-2,2′-bis(2-oxazoline)—are prepared. The hydrogels differ by the length of aliphatic chain of crosslinker and by the percentage of crosslinker (2–10%). The influence of the type and the percentage of the crosslinker on swelling properties, mechanical properties, and state of water is studied. The equilibrium swelling degree in water ranges from 2 to 20. With a proper selection of the crosslinker, Young's modulus can be varied from 10 kPa to almost 100 kPa. To evaluate the potential for medical applications, the cytotoxicity of extracts and the contact toxicity toward murine fibroblasts are measured. The hydrogels with the crosslinker containing a shorter aliphatic exhibit low toxicity toward fibroblast cells. Moreover, the viability and the proliferation of pancreatic β-cells incubated inside hydrogels for 12 days are analyzed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1548–1559

Effects of a cold atmospheric pressure plasma (CAPP) treatment on the germination, production of biomass, vigor of seedlings, uptake of water of wheat seeds (Triticum aestivum L. cv. Eva) were investigated. The CAPP treatment influence on the inactivation of microorganisms occurring on the surface of wheat seeds was investigated also. The so-called Diffuse Coplanar Surface Barrier Discharge generating a cold plasma in ambient air with high power volume density of some 100 W/cm3 was used for the treatment of seeds at exposure times in the range of 10–600 s. The optical emission spectroscopy and the electrical measurements were used for estimation of CAPP parameters. The obtained results indicate that the germination rate, dry weight and vigor of seedlings significantly increased for plasma treatment from 20 to 50 s. The plasma treatment of seeds led to an extensive increase in wettability and faster germination comparing with the untreated seeds. The growth inhibition effect of CAPP on the surface microflora of wheat seeds increased with the increase of the treatment time. The efficiency of the treatment of wheat seeds artificially contaminated with pure cultures of filamentous fungi decreased in the following order: Fusarium nivale > F. culmorum > Trichothecium roseum > Aspergillus flavus > A. clavatus.

The objective of this study was to determine the influence of low-temperature plasma (LTP) on seed surface modification, water uptake by seeds, seed germination and vigor of seedlings, as well as changes in the content of endogenous hormones in pea, (Pisum sativum L. var. Prophet). The study’s authors used diffuse coplanar surface barrier discharge as the source of LTP in various duration times of treatment (from 60 to 600 s). The SEM analysis showed that LTP induced significant changes on the seeds’ surface, which was related to water permeability into the seeds. LTP increased the germination percentage of pea seeds as well as the growth parameters (root and shoot length, dry weight), and the vigor of seedlings and the effects of LTP also depended on exposure time. The LTP-pretreatment produced changes in endogenous hormones (auxins and cytokinins and their catabolites and conjugates), which correlated with increased growth of the pea seedlings. The results suggested an interaction among the modification of seed structure demonstrated by LTP in the induction of faster germination and hormonal activities related to plant signaling and development during the early growth of pea seedlings.

The atmospheric pressure ambient air and oxygen plasma treatment of flat aluminum sheets using the so-called Diffuse Coplanar Surface Barrier Discharge (DCSBD) were investigated. The main objective of this study is to show the possibility of using DCSBD plasma source to activate and clean aluminum surface. Surface free energy measurements, X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM/EDX) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) were used for the characterization of the aluminum surface chemistry and changes induced by plasma treatment. Short plasma exposure times (several seconds) led to a significant increase in the surface free energy due to changes of its polar components. Various ageing effects, depending on the storage conditions were observed and discussed. Effects of air and oxygen plasmas on the removal of varying degrees of artificial hydrocarbon contamination of aluminum surfaces were investigated by the means of EDX, ATR-FTIR and XPS methods. A significant decrease in the carbon surface content after the plasma treatment indicates a strong plasma cleaning effect, which together with high energy efficiency of the DCSBD plasma source points to potential benefits of DCSBD application in processing of the flat aluminum surfaces.

In present study, the inhibition effect of low temperature plasma on Bacillus subtilis, Escherichia coli, Salmonella Enteritidis and B. subtilis endospores inoculated on the surface of black peppercorns was studied. Plasma was generated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) at atmospheric pressure in ambient air. Plasma treatment time of 300 s led to log10 CFU/g reduction of B. subtilis from 7.36 to 2.30 and B. subtilis endospores from 4.42 to 2.39. Plasma treatment reduced the number of E. coli and Salmonella Enteritidis to below detection level (1.0 log10 CFU/g) from initial populations of 7.45 log10 CFU/g and 7.60 log10 CFU/g, respectively. The inactivation kinetics was explained by Weibull model. Decimal reduction times (D-values) for B. subtilis, E. coli, Salmonella Enteritidis, and B. subtilis endospores were determined as 43 s, 47 s, 58 s, and 142 s, respectively. The surface morphology observed by Scanning Electron Microscopy showed no significant changes after the plasma treatment. The influence of plasma on chemical bonds on the surface and inside the peppercorns was studied by Attenuated Total Reflectance – Fourier Transform Infrared Spectroscopy.

Fabrication of a library of biocompatible hydrogels by photoinduced thiol-ene “click” reaction is described. The hydrogels are based on two different statistical copolymers consisting of 2-butenyl-2-oxazoline (EnOx) with either 2-methyl-2-oxazoline (MeOx) or 2-ethyl-2-oxazoline (EtOx). Crosslinking is achieved via pendant vinyl groups of EnOx in the copolymers with selected dithiol crosslinkers, namely dithiothreitol, 1,3-propanedithiol, 1,6-hexanedithiol, and 1,9-nonanedithiol by thiol-ene photocoupling. On the basis of different polarity and flexibility of particular dithiols and three different molar ratios to double bonds, it is possible to control swelling and mechanical characteristics of resulting hydrogels. Biocompatibility of all hydrogel types is verified by determination of toxicity of hydrogel extracts and contact direct toxicity towards mice 3T3 fibroblast cell line. The resulting low toxicity of all prepared hydrogels predetermines its utilization in biomedicine.

Current waveforms of the first negative corona pulses have been measured in O 2 + H 2 mixtures at a pressure range from 27 kPa to 50 kPa. It was observed that the hydrogen admixtures less than 4% do not change significantly the pulse current waveforms. Effects of changing cathode secondary electron emission were studied using a copper cathode coated by CuI and graphite. The results obtained support the theory of the cathode-directed streamer formation during the negative corona pulse rise.

We report on plasma surface treatment of sub-micron alumina powder by the Diffuse Coplanar Surface Barrier Discharge (DCSBD) in ambient air. Even though the isoelectric point did not change after plasma treatment, the results indicated an enhanced colloidal stability of treated powder, especially when ultrasonication was used as homogenization method. Suspensions prepared from plasma treated powder also exhibit lower pH values compared to those of original powder. FTIR analysis confirmed enhanced sorption ability of treated powder. Polycrystalline alumina ceramics prepared from the treated powder possess significantly finer microstructure compared to those prepared from untreated powders. These findings may have a significant impact on ceramic engineering. & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

In this study, surface modification of carbonyl iron (CI) particles with sulfobetaine moieties (SBE) was performed by the silanization of activated CI to form stable CI-SBE particles. The modification led to a significant improvement of the thermo-oxidation stability and a negligible suppression of the magnetization of the particles, as revealed by thermogravimetric analysis and vibrating sample magnetometry, respectively. The effect of a magnetic field and temperature on the magnetorheological performance of particle suspensions was investigated using a rotational rheometer in order to clarify the suitability of these systems for the local embolization of blood veins. The suspension based on CI-SBE exhibited a pseudoplastic behaviour and a tunable yield stress in a range from 0.3-4 kPa at the normal human body temperature. Moreover, cell viability for fibroblasts and macrophages was examined via MTT assay, which revealed their suitability for the intended applications for the local embolization of blood veins. The Royal Society of Chemistry 2016. Scopus

Effects of atmospheric filament-free diffuse plasma in ambient air and oxygen by Diffuse Coplanar Surface Barrier Discharge (DCSBD) on surface of indium tin oxide (ITO) were studied. The DCSBD plasma treatment resulted in significant reduction of water contact angles (even for 1 s long treatment). The decrease can be explained by the chemical changes on surface. These were studied by XPS which shows considerable decrease in the carbon surface concentration. The detailed analysis of C1s peak indicates the increase of the highest binding energy component of the C1s peak that corresponds to polar bonds with oxygen, which may be also related to decrease of water contact angle. AFM measurement showed no significant effect of plasma on ITO surface morphology.

The seeds of Zea mays L. cv. KWS were exposed to low-temperature plasma (LTP) by using Diffuse Coplanar Surface Barrier Discharge (DCSBD) for 60 and 120 seconds respectively. Growth parameters, anatomy of roots and activity of some enzymes (CAT, G-POX, SOD and DHO) isolated from roots grown from the seeds treated by LTP were evaluated. Our results indicate that LTP treatment of maize seeds affects post-germination growth of seedlings and this effect depends on the duration of LTP treatment. LTP treatment in duration of 60 seconds significantly increased the length, fresh and dry weight of the roots. However, the increase in time of LTP treatment to 120 seconds had inhibitive effect on the studied growth parameters. The activities of all studied antioxidant enzymes significantly increased with the age of maize seedlings in control conditions. On the other hand the application of LTP resulted in small, mostly non significant changes in the activity of antioxidant enzymes. Significant decrease in CAT activity was observed both in 3 and 6-day old maize roots and G-POX activity in 3-day old maize roots grown from seeds exposed to LTP for 60 seconds. A small, significant increase was detected only in SOD activity in 3-day old maize roots grown from seeds treated with LTP for 120 seconds and in 6-day old maize roots treated with LTP for 60 seconds. Significantly higher DHO activity was determined in embryos isolated from seeds treated with LTP for 60 seconds. On the contrary, in roots the DHO activity decreased with the time of LTP treatment. LTP treatment of seeds did not affect the anatomy of maize roots and caused only minor changes in the isoenzyme composition of G-POX and SOD.

Radial cuts of Pedunculate oak (Quercus robur L.) heartwood was activated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) plasma. The plasma treatment resulted in a considerable increase of free surface energy and in the substantial reduction of 50 μl water droplet uptake time. FTIR analysis confirmed the formation of additional polar functional groups on the wood surface due to the plasma treatment. This is consistent with the shift of wood surface pH level towards more acidic values. The energy efficiency of the DCSBD plasma treatment is better comparing to the known volume dielectric barrier discharge treatment method.