Browsing by Author "Stibor, Ivan"
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- ItemA comparative study between chemically modified and copper nanoparticle immobilized Nylon 6 films to explore their efficiency in fighting against two types of pathogenic bacteria(2020-01-05) Swar, Sumita; Máková, Veronika; Horáková, Jana; Kejzlar, Pavel; Parma, Petr; Stibor, IvanHospital-acquired infections (HAI) caused by pathogenic bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus adversely affect public health due to their colonization and subsequent formation of a biofilm on medical devices. Various functionalized polymers including polyamides are commonly used in the biomedical industry aiming to resist bacterial infection as well as to ensure cytocompatibility of the used materials. The present study is focused on the extension of our previous work that developed a new approach to immobilize mPEG on an amine-activated Nylon 6 surface. Herein, we compare functionalized samples of Nylon 6 together with samples additionally containing copper nanoparticles (Cu NPs, size 40-60 nm) physisorbed on a modified surface. Modified samples were analyzed via different techniques including water contact angle measurements, atomic force microscopy and scanning electron microscopy associated with energy dispersive Xray spectroscopy. The copper functionalized samples showed high antibacterial efficacy against Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. Moreover, most of the prepared samples were cytocompatible.
- ItemCarbon nanostructures grafted biopolymers for medical applications(2019-06-07) Slepičková Kasálková, Nikola; Žáková, Pavlína; Stibor, Ivan; Slepička, Petr; Kolská, Zdeňka; Karpíšková, Jana; Švorčík, VáclavEnhancing biopolymers with carbon nanostructures leads to the creation of attractive materials suitable for diverse medical application. We studied surface properties and cytocompatibility of amine functionalised carbon nanoparticles (CNPs) grafted on biopolymer film. Poly-L-lactic acid and poly-3-hydroxybutyrate were treated in an inert argon plasma discharge and subsequently grafted with three types of amine-functionalised CNPs. The surface properties of (i) CNPs and (ii) grafted CNPs were studied using multiple methods. BET, electrokinetic and XPS analyses confirmed the successful grafting of amino-compounds on the surface and also into the pores of CNPs. Goniometry approved the binding of the modified CNPs on the polymer surface. From AFM is evident that both the biopolymers show completely changed surface morphology after grafting of CNPs. The cytocompatibility test with vascular smooth muscle cells showed that the presence of the modified CNPs on polymer substrates has a more positive effect on cytocompatibility of PLLA rather than PHB.
- ItemControlled Preparation of Thermally Stable Fe-Poly(dimethylsiloxane) Composite by Magnetic Induction Heating(MDPI, 2019-05-07) Al-Harbi, Laila M.; Darwish, Mohamed S. A.; Khowdiary, Manal M.; Stibor, IvanThe most challenging task in the preparation of poly(dimethylsiloxane) composites is to control the curing time as well as to enhance their thermal and swelling behavior. Curing rate can be modified and controlled by a range of iron powder contents to achieve a desired working time, where iron is used as self-heating particles. Iron under alternative current magnetic field (ACMF) is able to generate thermal energy, providing a benefit in accelerating the curing of composites. Three types of iron-Poly(dimethylsiloxane) (Fe-PDMS) composites were prepared under ACMF with iron content 5, 10, and 15 wt %. The curing process was investigated by FTIR, while the morphology and the thermal stability were examined by SEM, DMA, and TGA. The heating’s profile was studied as functions of iron content and induction time. It was found that the time required to complete curing was reduced and the curing temperature was controlled by varying the iron content and induction time. In addition, the thermal stability and the swelling behavior of the prepared composites were enhanced in comparison with the conventional PDMS and thus offer a promising route to obtain thermally stable composites.
- ItemCyclodextrin-Polypyrrole Coatings of Scaffolds for Tissue Engineering(2019-03-11) Lukášek, Jan; Hauzerová, Šárka; Havlíčková, Kristýna; Strnadová, Kateřina; Mašek, Karel; Stuchlík, Martin; Stibor, Ivan; Jenčová, Věra; Řezanka, MichalPolypyrrole is one of the most investigated conductive polymers used for tissue engineering applications because of its advantageous properties and the ability to promote different cell types’ adhesion and proliferation. Together with β-cyclodextrin, which is capable of accommodating helpful biomolecules in its cavity, it would make a perfect couple for use as a scaffold for tissue engineering. Such scaffolds were prepared by the polymerisation of 6-(pyrrol-3-yl)hexanoic acid on polycaprolactone microfibres with subsequent attachment of β-cyclodextrin on the polypyrrole layer. The materials were deeply characterised by several physical and spectroscopic techniques. Testing of the cyclodextrin enriched composite scaffold revealed its better performance in in vitro experiments compared with pristine polycaprolactone or polypyrrole covered polycaprolactone scaffolds.
- ItemEffectiveness of Diverse Mesoporous Silica Nanoparticles as Potent Vehicles for the Drug L-DOPA(MDPI, 2019) Swar, Sumita; Máková, Veronika; Stibor, IvanOur study was focused on the synthesis of selective mesoporous silica nanoparticles (MSNs: MCM-41, MCM-48, SBA-15, PHTS, MCF) that are widely studied for drug delivery. The resulting mesoporous surfaces were conveniently prepared making use of verified synthetic procedures. The MSNs thus obtained were characterized by Brunauer-Emmett-Teller (BET) analysis and scanning electron microscopy (SEM). The selected MSNs with various pore diameters and morphologies were examined to evaluate the capability of L-DOPA drug loading and release. L-DOPA is a well-known drug for Parkinson's disease. The L-DOPA drug loading and release profiles were measured by UV-VIS spectroscopy and SBA-15 was proved to be the most effective amongst all the different types of tested mesoporous silica materials as L-DOPA drug vehicle.
- ItemFunctionalized Magnetic Nanoparticles and Their Effect on Escherichia coli and Staphylococcus aureus(Hindawi Publishing Corporation, 2015) Darwish, Mohamed S. A.; Nguyen, Nhung H. A.; Ševců, Alena; Stibor, IvanMagnetite (Fe3O4) nanoparticles were prepared using coprecipitation and subsequently surface-functionalized with 3-aminopropyltriethoxysilane (APTS), polyethylene glycol (PEG), and tetraethoxysilane (TEOS). Nanoparticle morphology was characterized using scanning electron microscopy, while structure and stability were assessed through infrared spectroscopy and zeta potential, respectively. Average size of the nanoparticles analysed by dynamic light scattering was 89 nm, 123 nm, 109 nm, and 130 nm for unmodified magnetite and APTS-, PEG-, and TEOS-modified magnetite nanoparticles, respectively. Biological effect was studied on two bacterial strains: Gram-negative Escherichia coli CCM 3954 and Gram-positive Staphylococcus aureus CCM 3953. Most of modified magnetite nanoparticles had a significant effect on S. aureus and not on E. coli, whereas PEG- magnetite nanoparticles displayed no significant effect on the growth rate of either bacteria.
- ItemMočovina-235 let plných překvapení(Technická Univerzita v Liberci, 2008) Zajícová, Veronika; Stibor, Ivan
- ItemModifikované vodivé nanomateriály na bázi heterocyklů(Technická Univerzita v Liberci, 2014) Martinek, Michal; Stibor, IvanDiplomová práce (DP) se zabývá vodivými polymery na bázi heterocyklických sloučenin, zejména pak polymery na bázi polypyrrolu a jeho derivátů. Tyto látky byly připravovány tzv. chemickou oxidační in situ polymerací z výchozích monomerů. Hlavní část práce je věnována modifikacím polyesterových vlákenných substrátů tenkými vrstvami derivátů polypyrrolu za účelem zvýšení jejich elektrické vodivosti a vytvoření nových vazebných míst na takto modifikovaném povrchu. Byl též studován efekt chemické úpravy substrátu za účelem zvýšení adheze vodivé vrstvy k podložce. Dále byly připraveny materiály na bázi nanovláken modifikovaných vodivou vrstvou funkcionalizových polypyrrolů. Vytvoření funkčních skupin provedeno v monomerní formě. Cílenou aplikací tohoto typu nanomateriálu je tkáňové inženýrství, zejména pak stimulace některých typů buněk elektrickým polem při současném využití funkčních vazebných míst (imobilizace růstových faktorů či dalších podpůrných látek). Výchozí monomery pro přípravu derivátů polypyrrolu byly též připravovány a studovány. V poslední řadě byl syntetizován i nový typ nanomateriálu nanotrubičky z polypyrrolu a jeho derivátů, které se vyznačují svojí specifickou strukturou (dutina s průměrem okolo 60 nm) a velkým měrným povrchem, při zachování elektrických vlastností a funkcionalizace. Také tento typ nanomateriálu by mohl nalézt uplatnění v oboru tkáňového inženýrství zejména regenerace nervových tkání.
- ItemNew Approach Towards m-PEG Grafting Onto Commercially Available Nylon 6 To Resist Bacterial Adhesion On Surface(IOP PUBLISHING LTD, DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND, 2018) Swar, Sumita; Zajícová, Veronika; Müllerová, Jana; Šubrtová, Petra; Stibor, IvanBiofilm formation, caused particularly by pathogenic bacteria like methicillin-resistant Staphylococcus aureus (MRSA) on medical devices, is imposing threat to public health. There is thus an ever growing demand for designing materials that are both cytocompatible and resistant to biofilm formation as well as bacterial infections. Surface functionalized polyamides, such as Nylon 6, are widely used as biomaterial due to its strength, flexibility, toughness and cytocompatibility. The undertaken study is focused on the surface functionalization of Nylon 6 by reducing the surface with borane-tetrahydrofuran complex (BH3-THF), followed by grafting with poly(ethylene glycol) methyl ether tosylate (mPEG-OTs) via a novel lithiation approach. The modified Nylon 6 surfaces were characterized by various techniques such as water contact angle (WCA) analysis, atomic force microscopy (AFM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) to confirm the modification of Nylon 6 surface. Evaluation of bacterial adhesion on the pure and modified surface against biofilm active pathogenic bacterial strain: Staphylococcus aureus (S.A.) CCM 3953 was accomplished. The functionalized Nylon 6 surfaces showed significant resistance towards bacterial adhesion compared to pure Nylon 6.
- ItemSeparation of racemic compound by nanofibrous composite membranes with chiral selector(ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2020-02-15) Gaálová, Jana; Yalcinkaya, Fatma; Cuřínová, Petra; Kohout, Michal; Yalcinkaya, Baturalp; Koštejn, Martin; Jirsák, Jan; Stibor, Ivan; Bara, Jason E.; Van der Bruggen, Bart; Izák, PavelA series of unique composite membranes formed from a nano&fibrous material with different amounts of a chiral selector was used for separation of chiral drugs. The membrane performances were demonstrated through sorption tests, wherein they were soaked in an aqueous solution of racemic D, L-tryptophan (a model chiral drug). The changes in concentration of both enantiomers over time were monitored by HPLC analysis. During 100 days, a blank membrane (without the chiral selector) exhibited no sorption activity. The membranes containing the selector had no influence on the amount of D-enantiomer, while the L-enantiomer was preferentially adsorbed on each membrane. The intensity of the sorption was found to be a direct function of the amount of the selector contained in a particular membrane. The separation of the same model chiral compound was further studied in diffusion cells by pertraction. The preferential sorption of L-tryptophan in the feed underlined the crucial importance of the selector in an active layer in view of chiral recognition of enantiomers. Due to the exclusive membrane material, the retention of L-tryptophan in the membrane materials did not block the passage of D-enantiomer into the permeate at any point during the experiment. Moreover, the nanomaterial in the active layer assured the distribution of the selector to the point that only 50% of (S, S)-1,2-diaminocyclohexane in one part of the active layer was sufficient to achieve 99% of enantioselectivity. The membranes - fresh and used - were analysed by Fourier-transform infrared (FTIR) spectroscopy and characterized by scanning electron microscopy (SEM) confirming the stability of the tested membranes. To complete the study, the role of the polyamide active layer in chiral recognition of tryptophan enantiomers was proposed.
- ItemSyntéza a funkcionalizace uhlíkatých nanomateriálů pro tkáňové inženýrství(Technická Univerzita v Liberci, 2016) Karpíšková, Jana; Stibor, Ivan
- ItemThe Covalent Tethering of Poly(ethylene glycol) to Nylon 6 Surface via N,N′-Disuccinimidyl Carbonate Conjugation: A New Approach in the Fight Against Pathogenic Bacteria(MDPI, 2020) Swar, Sumita; Máková,Veronika; Stibor, IvanDifferent forms of unmodified and modified Poly(ethylene glycols) (PEGs) are widely used as antifouling and antibacterial agents for biomedical industries and Nylon 6 is one of the polymers used for biomedical textiles. Our recent study focused on an efficient approach to PEG immobilization on a reduced Nylon 6 surface via N,N′–disuccinimidyl carbonate (DSC) conjugation. The conversion of amide functional groups to secondary amines on the Nylon 6 polymer surface was achieved by the reducing agent borane-tetrahydrofuran (BH3–THF) complex, before binding the PEG. Various techniques, including water contact angle and free surface energy measurements, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the desired surface immobilization. Our findings indicated that PEG may be efficiently tethered to the Nylon 6 surface via DSC, having an enormous future potential for antifouling biomedical materials. The bacterial adhesion performances against S. aureus and P. aeruginosa were examined. In vitro cytocompatibility was successfully tested on pure, reduced, and PEG immobilized samples.