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Kalay S.,Yeditepe University | Stetsyshyn Y.,Lvivska Polytechnika National University | Lobaz V.,Czech Institute of Macromolecular Chemical | Harhay K.,Lvivska Polytechnika National University | And 2 more authors.
Nanotechnology | Year: 2015

In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in a simple two-step process, where on the first step oligoperoxide was grafted via the interaction of amino groups (defects) of BNNTs with pyromellitic chloroanhydride fragments in oligoperoxide molecules. The second step involves N-isopropylacrylamide (NIPAM) graft polymerization 'from the surface' of oligoperoxide-functionalized BNNTs resulting in poly(N-isopropylacrylamide) (PNIPAM) coating. The pristine and functionalized BNNTs were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, dynamic light scattering, scanning electron microscopy and atomic force microscopy. PNIPAM-functionalized BNNTs exhibit excellent dispersibility in water and possess thermo-responsive properties. The water-dispersion of thermo-responsive PNIPAM-functionalized BNNTs can help their potential use in biomedical applications as 'smart' surfaces, nanotransducers and nanocarriers. © 2016 IOP Publishing Ltd. Source


Raczkowska J.,Jagiellonian University | Ohar M.,Lvivska Polytechnika National University | Stetsyshyn Y.,Lvivska Polytechnika National University | Zemla J.,Jagiellonian University | And 10 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2014

Poly(N-methacryloyl- l-leucine) (PNML) coatings were successfully fabricated via polymerization from peroxide initiator grafted to premodified glass substrate. Chemical composition and thickness of PNML coatings were determined using time of flight-secondary ion mass spectrometry (TOF-SIMS) and ellipsometry, respectively. PNML coatings exhibit thermal response of the wettability, between 4 and 28. °C, which indicates a transition between hydrated loose coils and hydrophobic collapsed chains. Morphology of the PNML coating was observed with the AFM, transforming with increasing temperature from initially relatively smooth surface to rough and more structured surface. Protein adsorption observed by fluorescence microscopy for model proteins (bovine serum albumin and lentil lectin labeled with fluorescein isothiocyanate) at transition from 5 to 25. °C, showed high affinity of PNML coating to proteins at all investigated temperatures and pH. Thus, PNML coating have significant potential for medical and biotechnological applications as protein capture agents or functional replacements of antibodies ("plastic antibodies"). The high proliferation growth of the human embryonic kidney cell (HEK 293) onto PNML coating was demonstrated, indicating its excellent cytocompatibility. © 2014 Elsevier B.V. Source


Stetsyshyn Y.,Lvivska Polytechnika National University | Zemla J.,Jagiellonian University | Zolobko T.,Lvivska Polytechnika National University | Fornal K.,Jagiellonian University | And 9 more authors.
Journal of Colloid and Interface Science | Year: 2012

Poly(N-isopropylacrylamide) (PNIPAM) coatings attached to glass with novel approach involving polymerization from oligoperoxide grafted to surface with (3-aminopropyl)triethoxysilane exhibit not only temperature- but also pH-dependence of wettability and protein adsorption. Wettability and composition of coatings, fabricated with different polymerization times, were determined using contact angle measurements and Time Of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS), respectively. Thermal response of wettability, measured between 20 and 40. °C, was prominent at pH 9 and 7 and diminished or absent at pH 5 and 3. This indicates a transition between hydrated loose coils and hydrophobic collapsed chains that is blocked at low pH. Higher surface roughness and dramatically increased adsorption of model protein (lentil lectin labeled with fluorescein isothiocyanate) were observed with AFM and fluorescence microscopy to occur in hydrophobic phases (at pH 3, for pH varied at constant temperature of 22. °C and at ∼33. °C, for temperature varied at constant pH 9). Protein adsorption response to pH was confirmed by TOF-SIMS and Principal Component Analysis. © 2012 Elsevier Inc. Source


Stetsyshyn Y.,Lvivska Polytechnika National University | Fornal K.,Jagiellonian University | Raczkowska J.,Jagiellonian University | Zemla J.,Jagiellonian University | And 9 more authors.
Journal of Colloid and Interface Science | Year: 2013

Poly(oligo(ethylene glycol)ethyl ether methacrylate (POEGMA246) coatings were successfully fabricated using novel approach via polymerization from oligoperoxide grafted to premodified glass substrate. Wettability, content and composition of coatings fabricated with different polymerization times were determined using contact angle measurements, ellipsometry and Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS). Thermo- and pH-responsive properties of POEGMA246 coatings were found to depend significantly on concentration of the grafted POEGMA246. Coatings fabricated with polymerization time 30. h exhibit not only temperature- but also pH-dependence of wettability. Thermal response of wettability, measured between 20 and 32. °C, was prominent at pH 9 and 7 and diminished or was absent at pH 5 and 3, indicating a transition between hydrated loose coils and hydrophobic collapsed chains, blocked at low pH. Protein adsorption, observed by fluorescence microscopy and analyzed semi-quantitatively using integral geometry approach, decreased dramatically for model protein (lentil lectin labeled with fluorescein isothiocyanate) at transition from pH 5 to pH 9, showing only very weak thermal-dependence. Strong protein adsorption response to pH and very weak one to temperature was confirmed by TOF-SIMS and Principal Component Analysis. © 2013 Elsevier Inc. Source


Stetsyshyn Y.,Lvivska Polytechnika National University | Kostruba A.,Lviv Academy of Commerce | Harhay K.,Lvivska Polytechnika National University | Donchak V.,Lvivska Polytechnika National University | And 5 more authors.
Applied Surface Science | Year: 2015

A multifunctional cholesterol-based peroxide modifier - monoperoxided monocholesteryl pyromellitate (PChP) with residual acid chloride groups has been synthesized. The structure of the peroxide modifier was confirmed using IR and 1H NMR spectroscopies. Grafted PChP coating was successfully fabricated onto amino-terminated glass surfaces. Thickness and refractive index of the coated layer, its morphology, wettability, and alignment of elongated PChP molecules, attached to the surface at different grafting times were characterized by means of ellipsometry, AFM, measurements of wetting contact angle and testing alignment of a nematic liquid crystal on the coatings. In a flat cell assembled of a pair of glass substrates coated with the PChP layer nematic molecules align preferentially tilted with respect to the cell normal, though in some place one finds homeotropic alignment, where nematic molecules are perpendicular to the surface. Liquid crystal textures visualize inhomogeneities in surface profile of the coated layer. Homeotropic alignment is observed in places where roughness of the layer is completely randomized in agreement with AFM data, providing visualization of evolution of the surface profile. Concentration of grafted molecules per area of the surface deduced from ellipsometry data suggests that PChP molecules are grafted to the surface rather densely already in about ten minutes. © 2015 Elsevier B.V. All rights reserved. Source

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