Publications by authors named "Pavlina Peikertova"

22 Publications

  • Page 1 of 1

Microstructure and Properties of Nanostructured Coating on Ti6Al4V.

Materials (Basel) 2020 Feb 5;13(3). Epub 2020 Feb 5.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Poruba, Czech Republic.

Implant surface properties of Ti6Al4V alloy that is currently used as a biocompatible material because of a variety of unique properties can be improved by a self-organized TiO layer. The TiO nanotubes forming on the titanium-based materials is a relatively recent technology for the surface properties modification and represents pronounced potential in promoting cell adhesion, proliferation, and differentiation that facilitate an implant osseointegration. This work focuses on the influence of surface treatment quality and anodic oxidation parameters on the structure features and properties of TiO nanotube coatings. The nanotubes were formed on Ti6Al4V alloy substrates by simultaneous surface oxidation and controlled dissolving of an oxide film in the presence of fluorine ions. The anodization process on ground or polished samples was performed at experimental condition of 30 V for 1 h. The selected anodized samples were heat treated for 2 h at 500 °C under flowing argon. All samples were characterized by scanning electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. The corrosion rate in physiological solution reached 0.0043, 0.0182, and 0.0998 mm per year for the samples in polished and not-anodized, as-anodized, and anodized-heat treated conditions, respectively.
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http://dx.doi.org/10.3390/ma13030708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040900PMC
February 2020

Polyaniline as a Precursor of Multi-Layer Graphene: Microscopic and Microspectroscopic Study.

J Nanosci Nanotechnol 2019 Dec;19(12):7736-7747

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Czech Republic.

Aluminosilicate-based nanocomposites containing multi-layer graphene were prepared from polyaniline/montmorillonite intercalate in two different forms: tablets and thin layers. Starting materials, polyaniline/montmorillonite powder and polyaniline/montmorillonite layers deposited on quartz glass, were prepared by polymerization of aniline in presence of montmorillonite particles. Powder was compacted into tablets using pressure 400 MPa. Samples were calcined at 1300 °C in argon atmosphere and multi-layer graphene was formed from polyaniline in both cases as confirmed by Raman microspectroscopy. Changes in morphology and surface conductivity of uncalcined and calcined samples were observed using atomic force microscopy and conductive atomic force microscopy. Also the differences between surface and internal volume of tablets were studied. Conductive atomic force microscopy revealed that the most conductive areas can be found solely on the edges of aluminosilicate particles formed from montmorillonite during calcination process. Detailed observation of multi-layer graphene in these areas was performed using transmission electron microscopy.
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http://dx.doi.org/10.1166/jnn.2019.15878DOI Listing
December 2019

Settled Dust from Urban and Suburban Roads in an Industrial City Area: Location and Seasonal Differences in Metal Content.

J Nanosci Nanotechnol 2019 May;19(5):3035-3040

Nanotechnology Centre, VŠ B-Technical University of Ostrava, 708 33 Ostrava-Poruba, Czech Republic.

Settled road dust, present on all roads surfaces in a relatively high abundance, is a complex of particles-ranging from nanosized to microsized-from both natural and anthropogenic sources and may pose possible risk to the biosphere as well as influence the atmosphere because of the road dust resuspension. Geographical and seasonal differences in heavy metal content of the settled road dust were studied at two sites: urban site with a heavy traffic in the industrial city of Ostrava, Czech Republic and suburban site of Ostrava with a negligible traffic load in settlement Ludgeřovice. Dust samples were collected monthly during the period from March to October 2015. Obtained dust samples were homogenized and subsequently analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy; the results were then assessed by multivariate statistical methods (Principal components analysis, Factorial analysis on mixed data). The difference in the content of Ba, Cr, Cu, Mn, Ni, Pb, Sb, Sn, V, and Zn was explainable mainly by the factor of the site only the content of Fe was significantly dependent on the month of sampling. The contents of the particular elements and the correlations found among them confirm the assumption that heavy metals detected in the road dust samples from the urban site most likely originated primarily from the traffic-and particularly from the non-combustion processes.
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http://dx.doi.org/10.1166/jnn.2019.15843DOI Listing
May 2019

Improvement of Glibenclamide Water Solubility by Nanoparticle Preparation.

J Nanosci Nanotechnol 2019 May;19(5):3031-3034

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Glibenclamide, a drug used for the treatment of type 2 diabetes, belongs to Class II of Biopharmaceutical Classification System. It is a highly permeable, but poorly water-soluble drug. Nanoparticles of glibenclamide were prepared by an emulsion solvent evaporation method using dichloromethane as a solvent of glibenclamide and 3% (w/w) aqueous solution of carboxymethyl dextran sodium salt as a stabilizer, which was found as optimal. A solubility test comparing the water solubility of glibenclamide bulk and nanoparticles confirmed the improved (2-fold higher) solubility of glibenclamide nanoparticles (0.045 g/ml) compared with bulk (0.024 g/ml).
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http://dx.doi.org/10.1166/jnn.2019.15876DOI Listing
May 2019

Nanogold Biosynthesis Mediated by Mixed Flower Pollen Grains.

J Nanosci Nanotechnol 2019 May;19(5):2983-2988

Department of Chemistry, Rajiv Gandhi University of Knowledge Technologies, AP IIIT, Nuzvid, Krishna District 521202, India.

Physical and chemical methods for nanoparticle synthesis are disadvantageous to less energy demanding and more efficient and environmentally friendly biological approaches. Thus, in this paper, we designed simple, bottom-up, , static experiment under laboratory conditions using suspension of mixed flower pollen grains for nanoparticle synthesis. Pollen grains provided template substrates for gold nanoparticles synthesis from dissolved Au(III). Transmission and scanning electron microscopy along with ultraviolet-visible spectra confirmed the gold nanoparticles formation. The biosynthesized/phytosynthesized gold nanoparticles had relative narrow size distribution (from 3 to 11 nm) with dominant spherical morphology with no aggregated forms. Thus, the gold nanoparticles in pollen dispersion provides excellent stability and dispersity.
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http://dx.doi.org/10.1166/jnn.2019.15853DOI Listing
May 2019

Determination of Oxidative Potential Caused by Brake Wear Debris in Non-Cellular Systems.

J Nanosci Nanotechnol 2019 May;19(5):2869-2875

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

Wear debris from automotive brake systems represents a major source of non-exhaust emissions from road traffic and its production increases with number of cars worldwide. However, impact of brake wear debris on the environment and organisms is still not clear. One of the most possible ways by which these particles may affect living organisms is oxidative stress. Production of reactive oxidative species may cause damage of basic cell components, lipids, proteins, etc. Aim of this study is to perform characterization of airborne and nonairborne fractions of brake wear debris generated during standard dynamometer tests and evaluation of its potential to induce oxidative stress via lipid peroxidation and carbonylation of proteins in non-cellular system. Elemental and phase composition were determined by scanning electron microscopy, Raman microspectroscopy, and X-ray powder diffraction analysis. Carbon in amorphous form and graphite, copper, and iron in form of oxides were identified as major components in both studied fractions. Characteristic size of studied wear particles was evaluated by dynamic light scattering. Both airborne and nonairborne samples showed ability to induce oxidative stress which results from determination of carbonylated proteins.
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http://dx.doi.org/10.1166/jnn.2019.15866DOI Listing
May 2019

Photoactive and Non-Hazardous Kaolinite/ZnO Nanocomposite: Characterization and Reproducibility of the Preparation Process.

J Nanosci Nanotechnol 2019 May;19(5):2862-2868

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

Photoactive and non-hazardous kaolinite/ZnO nanocomposite with 50 wt.% of ZnO nanoparticles was prepared using simple and cheap hydrothermal method. The resulting solid phase was separated by decantation, and dried at 105 °C. Calcination of the nanocomposites at 600 °C led to the kaolinite-metakaolinite phase transformation, to further growth of ZnO crystallites, and to significant increase in photodegradation activity. Whereas, for the several applications, e.g., in brake industry, the larger amount of composites is needed, thus, the evaluation of the reproducibility of preparation process is one of the crucial parameter. Prepared nanocomposites were deeply characterized by using X-ray fluorescence spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Rietveld quantitative phase analysis. Photodegradation activity was evaluated by the discoloration of Acid Orange 7 aqueous solution under UV irradiation. All used analytical techniques and methods confirm the reproducibility of the preparation process and as well that ZnO nanoparticles are anchored tightly on the clay surface which prevents the release to the environment.
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http://dx.doi.org/10.1166/jnn.2019.15860DOI Listing
May 2019

Stevensite-Rich Moroccan Clay Intercalated by Polypyrrole: Towards the Enhancement of Electrical Conductivity.

J Nanosci Nanotechnol 2019 May;19(5):2821-2832

Faculty of Metallurgy and Materials Engineering, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Czech Republic.

Regularly arranged chains strongly affect the electrical conductivity of conductive polymers (e.g., polypyrrole). One of the easiest ways to achieve this arrangement is the insertion of the polymer into the interlayer space of solid inorganic layered matrix, i.e., the intercalation process. Among various kinds of layered materials, the clay minerals, especially the smectite group, deserves particular attention. Negative charge of smectite layers helps the intercalation process resulting in higher conductivity of the polymer in clay/polymer intercalates. Characterization of stevensite-rich Moroccan clay and intercalation of electrically conductive polypyrrole into stevensite-rich Moroccan clay in order to obtain material with higher conductivity in comparison with pure polypyrrole were two main purposes of this work. Two forms of stevensite/polypyrrole nanocomposites were studied: powder and pressed tablets. X-ray fluorescence spectroscopy, X-ray diffraction analysis, atomic force microscopy, thermogravimetry, infrared spectroscopy, Raman microspectroscopy, and scanning electron microscopy in conjunction with energy dispersive X-ray spectroscopy were used to study the composition and structure of the nanocomposites. Measurement of electrical conductivity of polypyrrole in stevensite/polypyrrole nanocomposites revealed enhanced conductivity for all samples and also anisotropy in the conductivity of the samples pressed in the tablets.
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http://dx.doi.org/10.1166/jnn.2019.15875DOI Listing
May 2019

Micronization of Ibuprofen Particles Using Supercritical Fluid Technology.

J Nanosci Nanotechnol 2019 May;19(5):2814-2820

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

Most of drugs are only slightly soluble in the circulatory system of the human body. This reduces the efficiency of their use and that is why new ways how to increase their solubility are investigated. One way to improve the solubility of the drug is to reduce its particle size. Conventional techniques such as crushing or grinding usually do not guarantee a narrow particle size distribution, which is required for pharmaceuticals. Application of supercritical fluids, especially of supercritical CO₂, seems to be convenient method for the preparation of pharmaceuticals submicron particles or nanoparticles. The method enables the preparation of particles in a narrow size distribution and at the same time it does not leave any unwanted residues of solvents or other chemicals. The aim of this work is the micronization of ibuprofen particles using the supercritical fluid and characterization of formed products. The micronization of the particles was done using commercially available device Spe-ed SFE-4 in rapid expansion of supercritical solution mode. The applied temperatures and pressures were 308.15 K and 313.15 K and 200, 250 and 300 bar. The prepared particles were characterized using methods of X-ray diffraction, infrared spectroscopy, particle size distribution, scanning electron microscopy and tests of dissolution and permeability. Mean particles size was reduced from 180 m (original ibuprofen) to 2.8-7.3 m of the processed samples. The dissolution test confirmed better solubility and the permeability of newly formed particles improved.
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http://dx.doi.org/10.1166/jnn.2019.15874DOI Listing
May 2019

Stability of Calcium Deficient Hydroxyapatite/Clay Mineral Nanocomposite in Solutions with Different pH.

J Nanosci Nanotechnol 2019 May;19(5):2710-2716

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

Hydroxyapatite is one of the building blocks of hard tissues of living organisms. Therefore stability of nanoparticles in experimental solutions of different pH similar to one in human body is important issue for precise tailoring of the synthesis of hydroxyapatite particles on clay mineral substrate. In this study, the stability (amount of Ca and P released into the water) of calcium deficient hydroxyapatite/clay mineral nanocomposites was investigated. The calcium deficient hydroxyapatite/clay mineral nanocomposites with montmorillonite and two vermiculites (Brazil and Bulgaria) were compared with pure calcium deficient hydroxyapatite. The stability was investigated for 24 h where calcium deficient hydroxyapatite/clay mineral nanocomposites and pure calcium deficient hydroxyapatite were placed into the water solutions with different pH values (pH= 5, 7, and 9). The presence of Ca and P ions at solutions were determined using atomic emission spectrometry. The calcium deficient hydroxyapatite/clay mineral nanocomposites after stability testing were characterized by X-ray powder diffraction and infrared spectroscopy with Fourier transformation.
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http://dx.doi.org/10.1166/jnn.2019.15864DOI Listing
May 2019

Organovermiculite as Regenerable Nanostructured Adsorbent for Treatment of Heavily Polluted Waste Water from Coke Industry.

J Nanosci Nanotechnol 2019 May;19(5):2567-2574

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, Ostrava-Poruba 708 33, Czech Republic.

Organically modified vermiculites can be used as nanostructured adsorbents of organic compounds from waters or gaseous phases similarly as organically modified smectites or bentonites. There is a large amount of research data focused on adsorption properties of organoclays, however only a little information is about their post-sorption treatment. This work is focused on study of two possible ways of subsequent processing of organovermiculite after its use as sorbent for heavily polluted waste water. At first, the vermiculite modified with hexadecylpyridinium ions was used in batch static sorption against phenol ammonium water from the coke industry to get highly contaminated sorption material, especially containing organic hydrocarbons and their derivatives. The sorbent is known to have excellent sorption properties; however ecotoxicological characteristics of original material showed that sorbent had hazardous properties even before its utilization. For that reason, it was necessary to design a post-sorption treatment. Two possible methods of treatment were investigated, specifically solvent treatment (with dichloromethane) and thermal treatment (thermodesorption) at temperatures of 300 and 1100 °C, respectively. The treated materials were studied using infrared spectroscopy, X-ray diffraction and carbon phase analyses. The solvent treatment confirmed that it is possible to reuse modified vermiculite as adsorbent several times, although adsorption capacity after each extraction decreases. The thermal treatment at 300 °C was not sufficient to remove all organic compounds from the vermiculite structure; however at 1100 °C the only presence of magnesium silicate, magnesium aluminate and ferric oxide confirmed the formation of an inert material convenient for an environmentally harmless disposal of used adsorbent.
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http://dx.doi.org/10.1166/jnn.2019.15861DOI Listing
May 2019

Detection of Micron and Submicron Particles in Human Bronchogenic Carcinomas.

J Nanosci Nanotechnol 2019 May;19(5):2460-2466

Nanotechnology Centre, VŠB-Technical University of Ostrava, 708 33 Ostrava-Poruba, Czech Republic.

Metal based particles were detected in pulmonary tumor tissue samples and reference lung tissue samples (lung tissue without carcinoma) by Raman microspectroscopy and scanning electron microscopy. Many of these particles were in the size below 1 m. Using scanning electron microscopy, particles based on iron were found in the majority of samples. Siderite was determined as the form of the iron in several samples by Raman microspectroscopy. The hypothesis that significant statistical dependence exists between the presence of metals in the lung tissue and lung cancer incidence was not proved. However, statistical dependence between smoking and lung cancer incidence was determined as well as insignificant correlation between the presence of titanium based particles and lung cancer incidence. Titanium-based compounds were identified as TiO₂ in the form of anatase and rutile. Both the reference and the carcinoma samples exhibited magnetic properties as confirmed by vibration magnetometry measurements.
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http://dx.doi.org/10.1166/jnn.2019.15842DOI Listing
May 2019

Biological response of an in vitro human 3D lung cell model exposed to brake wear debris varies based on brake pad formulation.

Arch Toxicol 2018 07 10;92(7):2339-2351. Epub 2018 May 10.

BioNanomaterials Group, Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland.

Wear particles from automotive friction brake pads of various sizes, morphology, and chemical composition are significant contributors towards particulate matter. Knowledge concerning the potential adverse effects following inhalation exposure to brake wear debris is limited. Our aim was, therefore, to generate brake wear particles released from commercial low-metallic and non-asbestos organic automotive brake pads used in mid-size passenger cars by a full-scale brake dynamometer with an environmental chamber simulating urban driving and to deduce their potential hazard in vitro. The collected fractions were analysed using scanning electron microscopy via energy-dispersive X-ray spectroscopy (SEM-EDS) and Raman microspectroscopy. The biological impact of the samples was investigated using a human 3D multicellular model consisting of human epithelial cells (A549) and human primary immune cells (macrophages and dendritic cells) mimicking the human epithelial tissue barrier. The viability, morphology, oxidative stress, and (pro-)inflammatory response of the cells were assessed following 24 h exposure to ~ 12, ~ 24, and ~ 48 µg/cm of non-airborne samples and to ~ 3.7 µg/cm of different brake wear size fractions (2-4, 1-2, and 0.25-1 µm) applying a pseudo-air-liquid interface approach. Brake wear debris with low-metallic formula does not induce any adverse biological effects to the in vitro lung multicellular model. Brake wear particles from non-asbestos organic formulated pads, however, induced increased (pro-)inflammatory mediator release from the same in vitro system. The latter finding can be attributed to the different particle compositions, specifically the presence of anatase.
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http://dx.doi.org/10.1007/s00204-018-2218-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6015608PMC
July 2018

Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

Molecules 2016 Aug 2;21(8). Epub 2016 Aug 2.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide.
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http://dx.doi.org/10.3390/molecules21081005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274297PMC
August 2016

Microstructure, Optical and Photocatalytic Properties of TiO₂ Thin Films Prepared by Chelating-Agent Assisted Sol-Gel Method.

J Nanosci Nanotechnol 2016 Jan;16(1):504-14

Single and multilayer TiO₂ thin films coated on two types of soda-lime glass substrates (microscope slides and cylinders) were prepared by a chelating agent-assisted sol-gel method, using ethyl acetoacetate as a chelating agent, dip-coating and calcination at 500 °C for 2 h in air. Phase composition, microstructural, morphological and optical properties of thin films were comprehensively investigated by using XRF, advanced XRD analysis, Raman and UV-vis spectroscopy and AFM. It was found out that the thickness of thin films increases linearly with increasing number of deposited layers, indicating a good adhesion of the titania solution to a glass substrate as well as to a previously calcined layer. 1 layer film crystallized to anatase-TiO₂(B) mixture with minor/negligible amount of nanosized brookite, 2-4 layers films crystallized to anatase-brookite-TiO₂(B) mixture. In contrast to other multilayers films, 4 layers film was highly inhomogeneous. The different phase composition of thin films was clarified based on the crystallization via titanate/s and metastable monoclinic TiO₂(B) as a consequence of several phenomena; the diffusion of Na⁺ ions from a soda-lime glass substrate, acidic conditions and repeated thermal treatment. The multilayer films were in average highly transparent (80-95%) in the visible light region with the sharp absorption edge in the UV light region. Additionally, the photocatalytic properties of selected multilayer films were compared in AO7 photodegradation. Photocatalytic experiments showed that thicker 4 layers film of tricrystalline anatase-brookite-TiO₂(B) phase mixture was similarly active as thinner 3 layers film of similar phase composition, which may be a consequence of the inhomogeneity of the thicker film.
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http://dx.doi.org/10.1166/jnn.2016.10684DOI Listing
January 2016

Automotive airborne brake wear debris nanoparticles and cytokinesis-block micronucleus assay in peripheral blood lymphocytes: A pilot study.

Environ Res 2016 07 29;148:443-449. Epub 2016 Apr 29.

Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Instituttveien 18, 2007 Kjeller, Norway.

Motor vehicle exhaust and non-exhaust processes play a significant role in environmental pollution, as they are a source of the finest particulate matter. Emissions from non-exhaust processes include wear-products of brakes, tires, automotive hardware, road surface, and traffic signs, but still are paid little attention to. Automotive friction composites for brake pads are composite materials which may consist of potentially hazardous materials and there is a lack of information regarding the potential influence of the brake wear debris (BWD) on the environment, especially on human health. Thus, we focused our study on the genotoxicity of the airborne fraction of BWD using a brake pad model representing an average low-metallic formulation available in the EU market. BWD was generated in the laboratory by a full-scale brake dynamometer and characterized by Raman microspectroscopy, scanning electron microscopy, and transmission electron microscopy showing that it contains nano-sized crystalline metal-based particles. Genotoxicity tested in human lymphocytes in different testing conditions showed an increase in frequencies of micronucleated binucleated cells (MNBNCs) exposed for 48h to BWD nanoparticles (NPs) (with 10% of foetal calf serum in culture medium) compared with lymphocytes exposed to medium alone, statistically significant only at the concentration 3µg/cm(2) (p=0.032).
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http://dx.doi.org/10.1016/j.envres.2016.04.022DOI Listing
July 2016

Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

J Photochem Photobiol B 2015 Aug 19;149:265-71. Epub 2015 Jun 19.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; Regional Materials Science and Technology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation.
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http://dx.doi.org/10.1016/j.jphotobiol.2015.06.018DOI Listing
August 2015

Preparation, characterization and antibacterial properties of ZnO/kaoline nanocomposites.

J Photochem Photobiol B 2015 Jul 13;148:113-117. Epub 2015 Apr 13.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

This paper describes laboratory preparation, characterization and antibacterial activity testing of ZnO/kaoline composites. ZnO/kaoline composites with 50 wt.% of ZnO were laboratory prepared, dried at 105 °C and calcined at 500 °C. XRPD analysis revealed that thermal treatment caused the phase transformation of Zn containing precursor into ZnO. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A standard microdilution test was used for evaluation of antibacterial activity using four common human pathogens (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Daylight was used for induction photocatalytically based antibacterial activity. Second possible explanation of antibacterial activity of ZnO/kaoline could be the presence of biologically available forms of zinc. During the antibacterial activity assays the ZnO/kaoline composites exhibited antibacterial activity, where differences in an onset of the antibacterial activity and activity against bacterial strains were observed. The highest antibacterial activity was observed against S. aureus, where the lowest value of minimum inhibitory concentration was determined equal to 0.41 mg/ml.
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http://dx.doi.org/10.1016/j.jphotobiol.2015.03.034DOI Listing
July 2015

Preparation of risedronate nanoparticles by solvent evaporation technique.

Molecules 2014 Nov 4;19(11):17848-61. Epub 2014 Nov 4.

Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Palackeho 1/3, Brno 61242, Czech Republic.

One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III) was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations. The prepared samples were characterized by dynamic light scattering and scanning electron microscopy. Fourier transform mid-infrared spectroscopy was used for verification of the composition of the samples. The particle size of sixteen samples was less than 200 nm. Polysorbate, sodium carboxymethyl dextran and macrogol were determined as the most favourable excipients; the particle size of the samples of risedronate with these excipients ranged from 2.8 to 10.5 nm.
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http://dx.doi.org/10.3390/molecules191117848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271162PMC
November 2014

Antibacterial activity of kaolinite/nanoTiO2 composites in relation to irradiation time.

J Photochem Photobiol B 2014 Jun 18;135:17-22. Epub 2014 Apr 18.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Poruba, Czech Republic.

The paper addresses laboratory preparation and antibacterial activity testing of kaolinite/nanoTiO2 composite in respect of the daylight irradiation time. Kaolinite/nanoTiO2 composites with 20 and 40 wt% of TiO2 were laboratory prepared, dried at 105 °C and calcined at 600 °C. The calcination caused transformation of kaolinite to metakaolinite and origination of the metakaolinite/nanoTiO2 composite. X-ray powder diffraction, Raman and FTIR spectroscopic methods revealed titanium dioxide only in the form of anatase in all evaluated samples (non-calcined and calcined) and also transformation of kaolinite to metakaolinite after the calcination treatment. Scanning electron microscopy was used as a method for characterization of morphology and elemental composition of the studied samples. A standard microdilution test was used to determine the antibacterial activity using four human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa). A lamp with a wide spectrum bulb simulating daylight was used for induction of photocatalysis. The antibacterial assays found all the KATI samples to have antibacterial potency with different onset of the activity when calcined samples exhibited antibacterial activity earlier than the non-calcined. Significant difference in antibacterial activity of KATI samples for different bacterial strains was not observed.
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http://dx.doi.org/10.1016/j.jphotobiol.2014.04.004DOI Listing
June 2014

Detection of nano- and micro-sized particles in routine biopsy material - pilot study.

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2015 Mar 10;159(1):87-92. Epub 2012 Dec 10.

Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech RepublicbFaculty Hospital Ostrava, 17.listopadu 1790, 708 52 Ostrava cNanotechnology Center, VSB - Technical University Ostrava, 17. listopadu 15, 70833 Ostrava.

Background: Nanotechnology is receiving enormous funding. Very little however is known about the health dangers of this technology so far. Chronic tonsillitis is one of a number of diseases called idiopathic. Among other factors, the tonsils are exposed to suspended particles in inhaled air including nano particles. The objective of this study was to detect and evaluate metallic particles in human tonsil tissue diagnosed with chronic tonsillitis and in amniotic fluid as a comparison.

Methods: . Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) was used for identification of solid particles in a total of 64 samples of routinely analyzed biopsy and cytologic material.

Results: Almost all samples were found to contain solid particles of various metals. The most frequent, regardless of diagnosis, were iron, chromium, nickel and aluminium. The size, determined using SEM, varied from around 500 nm to 25 µm. The majority formed aggregates of several micrometers in size but there were a significant number of smaller (sub-micrometer or nano-sized) particles present. The incidence of metallic particles was similar in child and adult tissues. The difference was in composition: the presence of several metals in adults was due to occupational exposure.

Conclusions: The presence of metallic particles in pathologically altered tissues may signal an alternative causation of some diseases. The ethiopathogenic explanation of these diseases associated with the presence of nano-sized particles in the organism has emerged into a new field of pathology, nanopathology.
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http://dx.doi.org/10.5507/bp.2012.104DOI Listing
March 2015

Possible role of nano-sized particles in chronic tonsillitis and tonsillar carcinoma: a pilot study.

Eur Arch Otorhinolaryngol 2013 Feb 8;270(2):705-9. Epub 2012 Jun 8.

Department of Otolaryngology, University Hospital Ostrava, 17. Listopadu 1790, 708 52 Ostrava, Czech Republic.

This study aimed to evaluate the palatine tonsils of patients with chronic tonsillitis and spinocellular carcinoma to determine the presence of nano-sized particles. Tonsil samples from adult patients with chronic tonsillitis and spinocellular carcinoma of the palatine tonsil were dried and analyzed using a scanning electron microscope with the X-ray microprobe of an energy-dispersive spectroscope. Demographic data and smoking histories were obtained. The principal metals found in almost all tissues analyzed were iron, chromium, nickel, aluminum, zinc, and copper. No significant difference in elemental composition was found between the group of patients with chronic tonsillitis and the group with spinocellular carcinoma of the palatine tonsil. Likewise, no significant difference was found between the group of smokers and the group of nonsmokers. The presence of various micro- and nano-sized metallic particles in human tonsils was confirmed. These particles may potentially cause an inflammatory response as well as neoplastic changes in human palatine tonsils similar to those occurring in the lungs. Further and more detailed studies addressing this issue, including studies designed to determine the chemical form of the metals detected, studies devoted to quantitative analysis, biokinetics, and to the degradation and elimination of nanoparticles are needed for a more detailed prediction of the relation between the diagnosis and the presence of specific metal nanoparticles in tonsillar tissue.
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http://dx.doi.org/10.1007/s00405-012-2069-5DOI Listing
February 2013