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Polyoxazoline thin coatings were deposited on glass substrates using atmospheric pressure plasma polymerization from 2-ethyl-2-oxazoline vapours. The plasma polymerization was performed in dielectric barrier discharge burning in nitrogen at atmospheric pressure. The thin films stable in aqueous environments were obtained at the deposition with increased substrate temperature, which was changed from 20◦ C to 150◦ C. The thin film deposited samples were highly active against both S. aureus and E. coli strains in general. The chemical composition of polyoxazoline films was studied by FTIR and XPS, the mechanical properties of films were studied by depth sensing indentation technique and by scratch tests. The film surface properties were studied by AFM and by surface energy measurement. After tuning the deposition parameters (i.e., monomer flow rate and substrate temperature), stable films, which resist bacterial biofilm formation and have cell-repellent properties, were achieved. Such antibiofouling polyoxazoline thin films can have many potential biomedical applications. © MDPI AG. All rights reserved., Czech Science FoundationGrant Agency of the Czech Republic [GACR 19-15240S]; Ministry of Defence of the Czech Republic

Development of new types of antibacterial coatings or nanocomposites is of great importance due to widespread multidrug-resistant infections including bacterial infections. Herein, we investigated biocompatibility as well as structural, photocatalytic, and antibacterial properties of photoactive hydrophobic carbon quantum dots/polyurethane nanocomposite. The swell-encapsulation-shrink method was applied for production of these nanocomposites. Hydrophobic carbon quantum dots/polyurethane nanocomposites were found to be highly effective generator of singlet oxygen upon irradiation by low-power blue light. Analysis of conducted antibacterial tests on Staphyloccocus aureus and Escherichia coli showed 5-log bactericidal effect of these nanocomposites within 60 min of irradiation. Very powerful degradation of dye (rose bengal) was observed within 180 min of blue light irradiation of the nanocomposites. Biocompatibility studies revealed that nanocomposites were not cytotoxic against mouse embryonic fibroblast cell line, whereas they showed moderate cytotoxicity toward adenocarcinomic human epithelial cell line. Minor hemolytic effect of these nanocomposites toward red blood cells was revealed.

Investigation was made into the effect of plasma treatment on the release kinetics of the drug Temozolomide (TMZ) from thin, biodegradable polyester films, comprising polylactic acid (PLA) and poly...

Poly(lactic acid) (PLA) has shown much success in the preparation of tissue engineering scaffolds as it can be fabricated with a tailored architecture. However, the PLA surface has drawbacks including the lack of biofunctional motifs which are essential for high affinity to biological cells. Therefore, this study describes a multistep physicochemical approach for the immobilization of d-glucosamine (GlcN), a naturally occurring monosaccharide having many biological functions, on the PLA surface aiming at enhancing the cell proliferation activity. In this approach, poly(acrylic acid) (PAAc) spacer arms are first introduced into the PLA surface via plasma post-irradiation grafting technique. Then, covalent coupling or physical adsorption of GlcN with/on the PAAc spacer is carried out. Factors affecting the grafting yield are controlled to produce a suitable spacer for bioimmobilization. X-ray photon spectroscopic (XPS) analyses confirm the immobilization of GlcN on the PLA surface. The XPS results reveal also that increasing the yield of grafted PAAc spacer on the PLA surface increases the amount of covalently immobilized GlcN, but actually inhibits the immobilization process using the physical adsorption method. Contact angle measurements and atomic force microscopy (AFM) show a substantial increase of surface energy and roughness of PLA surface, respectively, upon the multistep modification procedure. The cytocompatibility of the modified surfaces is assessed using a mouse embryonic fibroblast (MEF) cell line. Observation from the cell culture basically demonstrates the potential of GlcN immobilization in improving the cytocompatibility of the PLA surface. Moreover, the covalent immobilization of GlcN seems to produce more cytocompatible surfaces if compared with the physical adsorption method. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3176-3188, 2017.

Nanostructured TiO2 nanotubes (NTs) of diameters from 15 to 100nm were fabricated by an electrochemical anodization process. Biofilm-positive strains of Bacillus cereus and Pseudomonas aeruginosa behaved similarly on all TiO2 NTs as well as on native titanium (Ti) foil. The adhesion and growth of mesenchymal stem cells (MSc), embryonic stem cells (ESc), and pure cardiomyocytes derived from ESc exhibited significant differences. MSc as well as ESc were, in contrast to cardiomyocytes, able to adhere, and grow on TiO2 NTs. A correlation between NTs diameter and cell behaviour was however observed in the case of MSc and ESc. MSc were not in a physiological state in the case of 100nm TiO2 NTs, while ESc were not able to grow on 15nm TiO2 NTs. It can be stated that these differences can be assigned to different diameters of the NTs but not to the chemistry of the surface. This is the first study describing the comprehensive behaviour of both eukaryotic and prokaryotic cells on TiO2 NTs. On the basis of obtained results, it can be concluded that new generation of medical devices providing selective cell behaviour can be fabricated by optimizing the nanoscale morphology of TiO2.

Conducting polymers (CP) can be used as pH- and/or electro-responsive components in various bioapplications, for example, in 4D smart scaffolds. The ability of CP to maintain conductivity under physiological conditions is, therefore, their crucial property. Unfortunately, the conductivity of the CP rapidly decreases in physiological environment, as their conducting salts convert to non-conducting bases. One of the promising solutions how to cope with this shortcoming is the use of alternative "doping" process that is not based on the protonation of CP with acids but on interactions relying in acidic hydrogen bonding. Therefore, the phosphonates (dimethyl phosphonate, diethyl phosphonate, dibutyl phosphonate, or diphenyl phosphonate) were used to re-dope two most common representatives of CP, polyaniline (PANI) and polypyrrole (PPy) bases. As a result, PANI doped with organic phosphonates proved to have significantly better stability of conductivity under different pH. It has also been shown that cytotoxicity of studied materials determined on embryonic stem cells and their embryotoxicity, determined as the impact on cardiomyogenesis and erythropoiesis, depend both on the polymer and phosphonate types used. With the exception of PANI doped with dibutyl phosphonate, all PPy-based phosphonates showed better biocompatibility than the phosphonates based on PANI.

Polyester urethane polymer was synthesized as linked biocompatible poly (lactide)/poly (ethylene oxide) polymers. The bulk polymer was subsequently used as precursor material for plasma assisted vapour thermal deposition of thin plasma polymer films under varying RF discharge power. The effect of plasma polymerization on the final physico-chemical characteristics was investigated. The chemical analysis of the films was performed using X-ray photoelectron spectroscopy and infrared spectroscopy. Structural analysis of plasma polymer thin film revealed the similar molecular structure as in case of precursor since PEU-characteristic bonds were preserved after the plasma polymerization. Surface properties analysed by a contact angle measurement revealed an increase of wettability in the samples prepared at higher RF power. At the same time a surface energy evaluated according to acid-base model decreased. The results indicate that plasma polymer films properties could be tuned depending on applied deposition conditions. © NANOCON 2019.All right reserved., Czech Science FoundationGrant Agency of the Czech Republic [GA17-10813S]

Polyoxazolines are a new promising class of polymers for biomedical applications. Antibiofouling polyoxazoline coatings can suppress bacterial colonization of medical devices, which can cause infections to patients. However, the creation of oxazoline-based films using conventional methods is difficult. This study presents a new way to produce plasma polymerized oxazoline-based films with antibiofouling properties and good biocompatibility. The films were created via plasma deposition from 2-methyl-2-oxazoline vapors in nitrogen atmospheric pressure dielectric barrier discharge. Diverse film properties were achieved by increasing the substrate temperature at the deposition. The physical and chemical properties of plasma polymerized polyoxazoline films were studied by SEM, EDX, FTIR, AFM, depth-sensing indentation technique, and surface energy measurement. After tuning of the deposition parameters, films with a capacity to resist bacterial biofilm formation were achieved. Deposited films also promote cell viability.

Polymeric biomaterials are widely used in medical applications owing to their low cost, processability and sufficient toughness. Surface modification by creating a thin film of bioactive agents is promising technique to enhance cellular interactions, regulate the protein adsorption and/or avoid bacterial infections. Polyethylene is one of the most used polymeric biomaterial but its hydrophobic nature impedes its further chemical modifications. Plasma treatment is unique method to increase its hydrophilicity by incorporating hydrophilic oxidative functional groups and tailoring the surface by physical etching. Furthermore, grafting of polymer brushes of amine group containing monomers onto the functionalized surface lead to strongly immobilized bioactive agents at the final step. Chondroitin sulphate is natural polysaccharide mainly found in connective cartilage tissue which used as a bioactive agent to immobilize onto polyethylene surface by multistep method in this study.

Novel composite films combining biocompatible polysaccharides with conducting polyaniline (PANI) were prepared via the in-situ polymerization of aniline hydrochloride in the presence of sodium hyaluronate (SH) or chitosan (CH). The composite films possess very good cytocompatibility in terms of adhesion and proliferation of two lines of human induced pluripotent stem cells (hiPSC). Moreover, the cardiomyogenesis and even formation of beating clusters were successfully induced on the films. The proportion of formed cardiomyocytes demonstrated excellent properties of composites for tissue engineering of stimuli-responsive tissues. The testing also demonstrated antibacterial activity of the films against E. coli and PANI-SH was able to reduce bacterial growth from 2 × 105 to < 1 cfu cm-2. Physicochemical characterization revealed that the presence of polysaccharides did not notably influence conductivities of the composites being ∼1 and ∼2 S cm-1 for PANI-SH and PANI-CH respectively; however, in comparison with neat PANI, it modified their topography making the films smoother with mean surface roughness of 4 (PANI-SH) and 14 nm (PANI-CH). The combination of conductivity, antibacterial activity and mainly cytocompatibility with hiPSC opens wide application potential of these polysaccharide-based composites.

A commercial formulation of poly(tetrafluoroethylene) (PTFE) sheets were surface modified by using non-thermal air at 40 kHz frequency (DC) and 13.56 MHz radiofrequency (RF) at different durations and powers. In order to assess possible changes of PTFE surface properties, zeta potential (&zeta, ), isoelectric points (IEPs) determinations, contact angle measurements as well as Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) imaging were carried out throughout the experimentation. The overall outcome indicated that &zeta, potential and surface energy progressively changed after each treatment, the IEP shifting to lower pH values and the implicit differences, which are produced after each distinct treatment, giving new surface topographies and chemistry. The present approach might serve as a feasible and promising method to alter the surface properties of poly(tetrafluoroethylene).

Low-density polyethylene films were surface modified through a three-step procedure to impart antibacterial property. Plasma treatment was followed by allylamine grafting to generate active functionalities on the surface. Three potent antibiotics including norfloxacin, ciprofloxacin and ofloxacin were then separately coated onto the surfaces. Each step of surface modification was well characterized in terms of chemical composition and bioactivity. It was found that the chemical structure of the antibiotic was highly determining in extent of antibiotic immobilization as well as in final biological performance of the modified substrates. An excellent activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial growth was observed for norfloxacin-coated substrate which corresponded to the highest amount of the antibiotic immobilized. However, almost no activity was seen for ofloxacin-coated surface. This was attributed to the ease of the antibiotic coating on the allylamine-grafted substrate where the lowest degree of coating was found for ofloxacin due to its unfavorable chemical structure. Gram-negative bacterial strain was found more vulnerable than Gram-positive strain which was explained on the basis of their different cell wall composition. The chemical structure of the antibiotic was found to be determining in amount of the material coated and also in level of the exhibited antibacterial activity.

A commercial formulation of styrene-acrylonitrile copolymer (SAN) sheets were surface-modified by using non-thermal radiofrequency and microwave plasma treatments. In order to evaluate the possible improvement of SAN surface properties, the modification was performed using oxygen and tetraflouromethane (CF4) discharges under different treatment durations and output powers. The untreated and treated samples were chemically and morphologically characterised by X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM), and surface charge was evaluated by zeta potential (ζ) measurements. In addition, water contact angle measurements were employed for evaluating the extent of hydrophilicity and hydrophobicity on the treated specimens. The overall outcome indicated drastic chemical and physical surface changes, which vary according to the carrier gas. Surface became noticeably hydrophilic after few seconds of oxygen plasma treatments, whilst the surface became hydrophobic after the CF4 treatments. The present approach might serve as a feasible and promising method to alter the surface properties of styrene-acrylonitrile copolymers.

Polyaniline is a promising conducting polymer with broad application potential in biomedicine. Its medical use, however, requires both biocompatibility and suitable physico-chemical and surface properties. The microstructure, electrical properties, and surface characteristics of polyaniline salt, polyaniline base, and polyaniline deposited with biologically active poly(2-acrylamido-2-methyl-1-propanesulfonic acid) were revealed using atomic force microscopy, contact angle measurements, and Raman spectroscopy. As conducting polymers can be preferentially applied in tissue engineering of heart and nervous tissues, the cardiomyogenesis in pure cardiomyocytes derived from embryonic stem cells and neurogenesis in neural progenitors isolated from embryonal 13 dpc brain were further investigated. The results show that neither cardiomyogenesis nor neurogenesis were influenced by any of the tested polyaniline films. However, the most favorable cell behaviour was observed on pristine polyaniline base; therefore, polyaniline in pristine forms without any further modification can be applied in a variety of biomedical fields.

Thin films based on polylactic acid have been prepared using plasma-assisted vacuum thermal deposition under varying RF glow discharge power and characterized in terms of chemical composition and structural homogeneity. As a measure of the degradability of the films their wash-off and hydrolysis behavior were monitored. The properties of the films were found to be tunable to a significant degree by the deposition conditions.

The cytocompatibility of cardiomyocytes derived from embryonic stem cells and neural progenitors, which were seeded on the surface of composite films made of graphene oxide (GO) and polypyrrole (PPy-GO) or poly(3,4-ethylenedioxythiophene) (PEDOT-GO) are reported. The GO incorporated in the composite matrix contributes to the patterning of the composite surface, while the electrically conducting PPy and PEDOT serve as ion-to-electron transducers facilitating electrical stimulation/sensing. The films were fabricated by a simple one-step electropolymerization procedure on electrically conducting indium tin oxide (ITO) and graphene paper (GP) substrates. Factors affecting the cell behaviour, i.e. the surface topography, wettability, and electrical surface conductivity, were studied. The PPy-GO and PEDOT-GO prepared on ITO exhibited high surface conductivity, especially in the case of the ITO/PPy-GO composite. We found that for cardiomyocytes, the PPy-GO and PEDOT-GO composites counteracted the negative effect of the GP substrate that inhibited their growth. Both the PPy-GO and PEDOT-GO composites prepared on ITO and GP significantly decreased the cytocompatibility of neural progenitors. The presented results enhance the knowledge about the biological properties of electroactive materials, which are critical for tissue engineering, especially in context stimuli-responsive scaffolds.

Low-density polyethylene (LDPE) foils were surface-modified by using non-thermal non-equilibrium oxidative air 40 kHz frequency, radiofrequency (RF) and microwave (MW) discharge plasma treatment. The pristine and treated specimens were morphologically and chemically characterised by Scanning Electron Microscopy (SEM) imaging, X-ray Photoelectron Spectroscopy (XPS) and contact angle measurement with surface energy evaluation. In addition, printability and ink adhesion tests were carried out on the samples, and quantitatively appraised by UV–VIS transmission spectroscopy. The overall outcome indicated chemical and physical changes after each treatment, and the improvement of printability. The present approach could serve as a viable and promising method to improve printability of polyethylene.

Conducting polyaniline can be prepared and modified using several procedures, all of which can significantly influence its applicability in different fields of biomedicine or biotechnology. The modifications of surface properties are crucial with respect to the possible applications of this polymer in tissue engineering or as biosensors. Innovative technique for preparing polyaniline films via in-situ polymerization in colloidal dispersion mode using four stabilizers (poly- N -vinylpyrrolidone; sodium dodecylsulfate; Tween 20 and Pluronic F108) was developed. The surface energy, conductivity, spectroscopic features, and cell compatibility of thin polyaniline films were determined using contact-angle measurement, the van der Pauw method, Fourier-transform infrared spectroscopy, and assay conducted on mouse fibroblasts, respectively. The stabilizers significantly influenced not only the surface and electrical properties of the films but also their cell compatibility. Sodium dodecylsulfate seems preferentially to combine both the high conductivity and good cell compatibility. Moreover, the films with sodium dodecylsulfate were non-irritant for skin, which was confirmed by their in‐vitro exposure to the 3D-reconstructed human tissue model.

This article describes the novel possibility of the polyester (polyethylene terephthalate) surface modification by plasma treatment. Moreover, this modified polyester could be component for the composite material (with hyaluronic acid) used in the wound healing. In this study, the experimental methods: FT-IR spectroscopy, the contact angle measurement, x-ray photoelectron spectroscopy and scanning electron microscopy were used for the surface modified polyester characterisation.

A multistep physicochemical approach was adopted to develop a novel surface active antibacterial medical-grade polyvinyl chloride (PVC). This was accomplished through surface activation via diffuse coplanar surface barrier discharge plasma in air at ambient temperature and pressure, followed by radical graft copolymerization of acrylic acid onto the surface via grafting-from pathway to yield a well-defined high density brush. Irgasan as a potent biocide was then coated onto the functionalized surface to impart antimicrobial properties. Contact angle measurements showed an improved hydrophilicity upon multistep modifications. Alterations in surface free energy values were tracked through various known models. The equilibrium water absorption test corroborated the contact angle analysis. Scanning electron microscopy revealed etched features on the plasma treated sample as well as a brush-like pattern on the graft copolymerized surface. Surface chemistry was explored by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS), which confirmed the presence of irgasan non-covalently anchored onto the surface. An excellent bacteriostatic performance was exhibited by the irgasan coated sample using the agar diffusion test method against two potentially pathogenic gram-negative and particularly gram-positive bacterial strains implying a facile release of the antibacterial agent. However, in vitro bacterial adhesion and biofilm formation assays indicated incapability of irgasan in hindering the adherence after 24 h incubation. Nevertheless, the plasma treated and graft copolymerized samples were appreciably effective to diminish the adherence of gram-negative strain. Wettability and surface configuration of the substrate, besides bacteria structural characteristics, were established to be crucial factors in the adhesion phenomenon. The irgasan coated medical-grade PVC was suggested to be suited for use in disposable medical catheters of dependable antimicrobial performance.

A number of polyvinyl chloride (PVC) applications require a modification of surface properties of the polymer. In the present work, the effects of plasma treatment on the resulting surface, includi...

The bacterial strains of Rhodococcus sp. S3E2 and Rhodococcus sp. S3E3 were selected for adhesion study on Teflon-like or organosilicon thin films deposited on paper substrate in atmospheric pressure surface barrier discharge. As a carrier gas the nitrogen with small admixture of octafluorocyclobutane or hexamethylenedisiloxane was used. The influence of octafluorocyclobutane and hexamethylenedisiloxane flow rate ratio on later cell adhesion was studied. The cell attachment was evaluated by means of the luminometric measurement of the ATP extracted from adhered cells. The surface properties of deposited layers were investigated by means contact angle measurement and chemical properties of deposited films were studied by means of FTIR spectroscopy. Optical emission spectroscopy was used for investigation of plasma parameters of used plasma.

The adhesion of Yarrowia lipolytica to teflonlike thin films deposited by plasma on polycarbonate substrates was investigated through a series of tests in order to develop a substrate for strong and selective adhesion of Yarrowia lipolytica cells. Teflonlike thin films were prepared using atmospheric pressure surface barrier discharge with mixtures of octafluorocyclobutane (C4F8) and nitrogen as plasma gas. A variety of plasma gas feedrates and different deposition times were studied. The films were characterised by Fourier transform infrared and contact angle measurements using the sessile drop technique. Total surface energy and its components were calculated using the acid base theory. Attachment of the yeast cells was assessed by optical and scanning electron microscopy. The optimal deposition conditions for cell adhesion were determined using standard adhesion tests.

Bio-interactive and bio-inert materials prepared by plasma deposition of organosilicon thin films on polycarbonate substrates were studied and described in this communication. The atmospheric pressure surface barrier discharge was applied. Nitrogen with small admixture of hexamethyldisiloxane (HMDSO) was used as plasma discharge gas. The zeta potential measurement followed by cell adhesion to polystyrene was used to find optimal values of stability of the cell suspension and cell adhesion to the tested surfaces. The samples of plasma deposited layers were characterized by contact angle measurement.

SiO2/polystyrene nanocomposite particles were synthesized via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as surfactant and hexadecane as hydrophobe in the presence of silica particles coated with methacryloxy(propyl)trimethoxysilane (MPS) surface coupling agent. The silica particles were individually coated with polymer yielding a very homogenous nanocomposite latex which was very stable in a wide range of ionic strengths. Monomer conversion was reasonably high and fast.

An influence of simulated ageing on the adhesive joint of plasma treated polyethylene (PE) and polypropylene (PP) was tested. Plasma surface treatment was performed in the rf-plasma reactor operating at 13,56 MHz. The simulated ageing of prepared specimens for following tensile testing was carried out under conditions given by Volkswagen standard P-VW 1200. Temperature of ageing was regularly oscillating between −40°C and 80°C (relative humidity 80%) for required time. The mechanical tensile properties of adhesive joint were measured according to the standard ISO 527. Surface analysis of treated polymer substrates was characterized by XPS measurement. The observation of surface structure and morphology was obtained using SEM. We used convenient cyanoacrylate adhesive Loctite E 406 for PE and PP joints. Tested adhesive joints were prepared in compliance with the standard ISO 4587.

The effective and widely tested biocides: Benzalkonium chloride, bronopol, chitosan, chlorhexidine and irgasan were added in different concentrations to atelocollagen matrices. In order to assess how these antibacterial agents influence keratinocytes cell growth, cell viability and proliferation were determined by using MTT assay. Acquired data indicated a low toxicity by employing any of these chemical substances. Furthermore, cell viability and proliferation were comparatively similar to the samples where there were no biocides. It means that regardless of the agent, collagen-cell-attachment properties are not drastically affected by the incorporation of those biocides into the substrate. Therefore, these findings suggest that these atelocollagen substrates enhanced by the addition of one or more of these agents may render effectiveness against bacterial stains and biofilm formation, being the samples referred to herein as "antimicrobial substrates" a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications., European Regional Development Fund (ERDF)European Commission; national budget of Czech Republic [CZ.1.05/2.1.00/03.0111]; Advanced Theoretical and Experimental Studies of Polymer Systems [CZ.1.07/2.3.00/20.0104]

A physico-chemical approach to modify surfaces not only for use in medicine, but also for preservation of food is nowadays widely studied to lower the risks of increased number of bacterial pathogens that are in a direct contact with people. Food safety is very important part of preserving sustainability during crises, especially after the enterohaemorrhagic Escherichia coli outbreak in Europe in 2011. One of the possibility how we can protect food against various pathogens is the modification of packing materials that are directly in contact with preserved food. This contribution deals with the characterization of modified surfaces with antibacterial properties via Terahertz spectroscopy. For the purpose of this paper, three monomers were used for grafting onto air radiofrequency plasma activated low density polyethylene surface, which created a brush-like structure. Next, the antibacterial agents, Irgasan and Chlorhexidine, were anchored to these surfaces. These antibacterial agents were selected for supposed effect on two most frequently occurring bacterial strains - Escherichia coli and Staphylococcus aureus. Materials were further tested for the presence of antibacterial agent molecules, in our case by means of terahertz spectroscopy. Each material was tested on two spectroscopes - the SPECTRA and the OSCAT terahertz instruments.

Limiting factor of PE application in healthcare is high susceptibility of polyethylene towards bacterial growth. For this reason, antibacterial treatment of PE foils using appropriate antibacterial agents was used in this work. Benzalkonium chloride and bronopol were selected due to their satisfactory antibacterial effect confirmed by applications in medical and cosmetic industry. These antibacterial agents were immobilized onto PE surface by a multistage approach via polyacrylic acid brushes grafting onto the PE surface pre-treated by low-temperature plasma. Measurements of surface energy, X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) were used for investigation of surface changes after antibacterial modification of PE. Moreover, the antibacterial effect was evaluated by inhibition zone measurements of Staphylococcus aureus and Escherichia coli bacterial strains. qscience

Polyamide (PA) 6 was modified by diffuse coplanar surface barrier discharge (DCSBD) plasma in an atmosphere of nitrogen and oxygen. The surface roughness decrease of PA 6 was detected by AFM and nano-indentation after modification in DCSBD plasma. A significant increase in O/C and N/C ratios of plasma-modified PA 6 using XPS analysis was found. The results show the importance of introducing oxygenic polar functional groups on the polymeric surface in order to increase its surface energy during a short time of plasma activation. The modification of PA 6 by DCSBD oxygen plasma was more efficient than by nitrogen plasma. Ministry of Education of the Slovak Republic and Slovak Academy of Sciences, projects VEGA (grants no. 2/0185/10, 2/0199/14, and 1/0581/12) as well to the Ministry of Education, Youth and Sport of the Czech Republic (CZ.1.05/2.1.00/03.0111) Scopus

Ferroelectrics have been, among others, studied as electroactive implant materials. Previous investigations have indicated that such implants induce improved bone formation. If a ferroelectric is immersed in a liquid, an electric double layer and a diffusion layer are formed at the interface. This is decisive for protein adsorption and bioactive behaviour, particularly for the adhesion and growth of cells. The charge distribution can be characterized, in a simplified way, by the zeta potential. We measured the zeta potential in dependence on the surface polarity on poled ferroelectric single crystalline LiNbO3 plates. Both our results and recent results of colloidal probe microscopy indicate that the charge distribution at the surface can be influenced by the surface polarity of ferroelectrics under certain 'ideal' conditions (low ionic strength, non-contaminated surface, very low roughness). However, suggested ferroelectric coatings on the surface of implants are far from ideal: they are rough, polycrystalline, and the body fluid is complex and has high ionic strength. In real cases, it can therefore be expected that there is rather low influence of the sign of the surface polarity on the electric diffusion layer and thus on the specific adsorption of proteins. This is supported by our results from studies of the adhesion, growth and the activity of alkaline phosphatase of human osteoblast-like Saos-2 cells on ferroelectric LiNbO3 plates in vitro.

Low-density polyethylene (LDPE) belongs to commodity polymer materials applied in biomedical applications due to its favorable mechanical and chemical properties. The main disadvantage of LDPE in biomedical applications is low resistance to bacterial infections. An antibacterial modification of LDPE appears to be a solution to this problem. In this paper, the chitosan and chitosan/pectin multilayer was immobilized via polyacrylic acid (PAA) brushes grafted on the LDPE surface. The grafting was initiated by a low-temperature plasma treatment of the LDPE surface. Surface and adhesive properties of the samples prepared were investigated by surface analysis techniques. An antibacterial effect was confirmed by inhibition zone measurements of Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). The chitosan treatment of LDPE led to the highest and most clear inhibition zones (35 mm 2 for E. coli and 275 mm 2 for S. aureus ).

Collagen films (Atelocollagen from bovine Achilles tendon) were prepared in tissue culture dishes and their surfaces were modified by using air and nitrogen plasma treatment. The treated samples were characterised by surface probe techniques including attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy imaging (SEM) and X-ray photoelectron spectroscopy (XPS). In addition, human immortalised non-tumorigenic keratinocyte cell line (HaCaT) was seeded on the treated and untreated films and cell proliferation was measured by using MTT assay test. The characterisation results confirmed physical and chemical changes on the collagen surface, such as increase in the extent of surface oxidation and surface roughness as well as, the treated samples showed better cell growth than untreated ones, and therefore this approach may be taken into account in the development of promising materials for tissue regeneration applications.

The antibacterial surfaces presented can be one of the solutions for lowering the risk of pathogen outbreaks. Samples were prepared via a multistep physicochemical approach and characterized by terahertz spectroscopy. Properties of modified materials were analyzed using two spectrometers—terahertz pulsed imaging and spectroscopy Spectra [attenuated total reflection (ATR) and transmission module] and Tera optical sampling by cavity tuning. Each sample was measured 3 to 10 times to get accurate results. Observed regions for the transmittance module were set to 0 to 2.6 THz, and 0 to 4 THz for the ATR module. The obtained refractive indices allowed for easy distinguishing between each material. Absorbance spectra were assigned where possible as was the peak position that showed successful bonding of the used monomers/antibacterial agents. Measured dielectric properties described slight changes in materials due to the modification process. The experimentally analyzed transmittance displayed changes in every material up to the 2.6 THz region and Fabry–Perot interferences together with water vapor noise beyond this area. The section containing terahertz imaging of the samples is presented. The present work is one of the first of its kind. The possibility of using terahertz spectroscopy for characterizing materials with antibacterial agents bonded by intermolecular forces onto a treated surface is presented.

Polyaniline is a promising conducting polymer with still increasing application potential in biomedicine. Its surface modification can be an efficient way how to introduce desired functional groups and to control its properties while keeping the bulk characteristics of the material unchanged. The purpose of the study was to synthetize thin films of pristine conducting polyaniline hydrochloride, non-conducting polyaniline base and polyaniline modified with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and investigate chosen parameters of their hemocompatibility. The modification was performed either by introduction of PAMPSA during the synthesis or by reprotonation of polyaniline base. The polyaniline hydrochloride and polyaniline base had no impact on blood coagulation and platelet adhesion. By contrast, the polyaniline reprotonated with PAMPSA completely hindered coagulation thanks to its interaction with coagulation factors Xa, Va and IIa. The significantly lower platelets adhesion was also found on this surface. Moreover, this film maintains its conductivity at pH of 6, which is an improvement in comparison with standard polyaniline hydrochloride losing most of its conductivity at pH of 4. Polyaniline film with PAMPSA introduced during synthesis had an impact on platelet adhesion but not on coagulation. The combined conductivity, anticoagulation activity, low platelet adhesion and improved conductivity at pH closer to physiological, open up new possibilities for application of polyaniline reprotonated by PAMPSA in blood-contacting devices, such as catheters or blood vessel grafts. © 2015 Elsevier B.V.., Czech Science Foundation [13-08944S]; Ministry of Education, Youth and Sport of the Czech Republic [CZ.1.05/2.1.00/03.0111]; TBU in Zlin [IGA/FT/2014/004]

Adsorption of the dyes on the surface of the natural and synthetic polymer fibers, or weaved fabrics is created due to the effect of the intermolecular forces between fiber surface and the dye. Such forces are causing relatively strong bonding interaction between dye dipoles and the stained matrix. In the case of polymer and biopolymer materials the number of the dipoles is directly proportional to the number of polar groups in macromolecular side chains. The latter number of present dipoles is possible to be increased by several physico-chemical methods, e.g. fire treatment, chemical etching by strong acids, UV irradiation, corona discharge or low-temperature plasma treatments etc. In this communication the effect of low-temperature plasma treatment of polyester (PES) weaved fabric on dye adsorption to the surface of the studied substrate is discussed. Obtained increased dye selectivity to the stained matrix results in improved tinctorial strength, better economical effectiveness as well as to the improved ecology of the process.