Browsing by Author "Kopcansky, Peter"

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Bio-inorganic nanocomposites of lysozyme amyloid fibrils and magnetic nanoparticles of different shape anisotropy
(2020-05-15)
Lackova, Veronika
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Tomasovicova, Natalia
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Olejniczak, Andrzej
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Zakutanska, Katarina
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Majorosova, Jozefina
The present study describes the interaction of an assorted shape of magnetic nanoparticles with lysozyme amyloid fibrils by atomic force microscopy and magnetization measurements. Mixture stability was verified by settling behaviour of NPs dispersions. A fibril solution doped with spherically shaped magnetic nanoparticles reveals the effect of particles' adsorption on the amyloid fibrils' surface. However, when spindle-like magnetic nanoparticles were doped, it led to zero interaction activity, which confesses subtle difference in fibrillary interaction with spherical particle that can be explained by diverse size of nanoparticles. Moreover, spherical MNPs showed excellent stability in sLAF, the spindle MNPs were unstable and exhibited limited dispersion.
Dual Size-Dependent Effect of Fe3O4 Magnetic Nanoparticles Upon Interaction with Lysozyme Amyloid Fibrils: Disintegration and Adsorption
(2019-01-01)
Tomasovicova, Natalia
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Hu, Po-Sheng
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Zeng, Cyun-Lun
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Majorosova, Jozefina
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Zakutanska, Katatina
Nanomedicine compounds containing nanoparticles, such as iron oxides and gold, have been demonstrated to be effective in promoting different magnitudes of interaction with amyloid beta fibrils, of which disintegrating or inhibiting effects are of great importance to treating fibrillary aggregation-induced neurological disorders such as Alzheimer's disease. This research herein studies the interaction between lysozyme amyloid fibrils, a type of fibers derived from hen egg white lysozyme, and Fe3O4 magnetic nanoparticles (MNPs) of an assorted diameter sizes of 5 nm, 10 nm and 20 nm, using atomic force microscopy (AFM). Specifically, the effects of the sizes of negatively charged MNPs on the resultant amyloid fibrillary mixture was investigated. Our results of AFM images indicated that the interaction between MNPs and the fibrils commences immediately after adding MNPs to the fibril solution, and the actions of such MNPs-doped fibrillary interplay, either integration or segmentation, is strongly dependent on the size and volume concentration of MNPs. In the cases of 5 nm and 20 nm particles of equivalent volume concentration, the adsorption and agglomeration of MNPs onto the fibrillary surfaces was observed, whereas, interestingly, MNPs with diameter size of 10 nm enables segmentation of the slender fibrils into debris when a proper implemented volume concentration was found, which signifies utter destruction of the amyloid fibrillary structure.
Dynamic morphogenesis of dendritic structures formation in hen egg white lysozyme fibrils doped with magnetic nanoparticles
(2018-01-01)
Tomasovicova, Natalia
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Hu, Po-Sheng
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Zeng, Cyun-Lun
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Hurakova, Maria
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Csach, Kornel
In this research, the dynamic process of aggregation that forms microflower morphology in solution of lysozyme amyloid fibrils doped with spherical or spindle-like magnetic nanoparticles during the process of drying as well as their final microstructures were investigated. The prepared lysozyme amyloid fibrils as well as their mixtures with in-lab synthesized magnetic particles, which were prepared by adding the nanoparticles to the fibrils solution after the process of fibrillation was done, were characterized using brightfield trans-illumination-mode optical microscope, atomic force microscopy (AFM) and scanning electron microscope (SEM). Brightfield optical imaging bases upon photoabsorptive property of the fibrils-nanoparticle composites clearly reveals the morphological features in microscale, and additionally, for the in vivo, live action of the time-dependent process of self-assembly of such composites composed of fibrillary structure incorporated with magnetic particles was optically elucidated at ambient temperature. Moreover, while results of AFM reveal delicate and peculiar association of fibrils with magnetic nanoparticles of different shapes, SEM images illustrate a stark difference in fine detailed final morphology of microstructures associated with spherical and spindle-like nanoparticles. Our results indicated that the interaction between fibrils solution and the nanoparticles commence right after mixing, the dynamic process of forming dendritic structure resembling microflower morphology is on the order of minutes, and its final structure is highly dependent on the shape of magnetic nanoparticles. (C) 2017 Elsevier B.V. All rights reserved.
Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites
(1970-01-01)
Majorosova, Jozefina
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Schroer, Martin A.
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Tomasovicova, Natalia
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Batkova, Marianna
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Hu, Po-Sheng
We present colloidal nanocomposites formed by incorporating magnetite Fe3O4 nanoparticles (MNPs) with lysozyme amyloid fibrils (LAFs). Preparation of two types of solutions, with and without addition of salt, was carried out to elucidate the structure of MNPs-incorporated fibrillary nanocomposites and to study the effect of the presence of salt on the stability of the nanocomposites. The structural morphology of the LAFs and their interaction with MNPs were analyzed by atomic force microscopy and small-angle x-ray scattering measurements. The results indicate that conformational properties of the fibrils are dependent on the concentration of protein, and the precise ratio of the concentration of the protein and MNPs is crucially important for the stability of the fibrillary nanocomposites. Our results confirm that despite the change in fibrillary morphology induced by the varying concentration of the protein, the adsorption of MNPs on the surface of LAF is morphologically independent. Moreover, most importantly, the samples containing salt have excellent stability for up to 1 year of shelf-life.
Hyperthermia Induced by Near-Infrared Laser-Irradiated CsWO3 Nanoparticles Disintegrates Preformed Lysozyme Amyloid Fibrils
(2020-03-01)
Hu, Po-Sheng
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Tomasovicova, Natalia
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Chou, Hsiu-Jen
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Li, Meng-Chang
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Vojtko, Marek
This research study attempts to prove the concept of the applicability of hyperthermia to treating the lysozyme amyloid fibrils (LAFs)'s self-assembled fibrillary aggregates by a feedback-modulated temperature controller ranging from 26 degrees C to 80 degrees C, and separately, by near-infrared (NIR) laser-irradiated cesium tungstate (CsWO3) nanoparticle (NPs). The dependence of the final morphology of the amyloidal assembly on external heating and the photothermal effect of the NPs on treating the fibrillary assembly were investigated and analyzed. Experimentally, atomic force microscopy (AFM), optical stereoscopy, and scanning electron microscopy (SEM) were used primarily to ensure mutual interaction between LAFs and NPs, optically elucidate the surface contour and final fibrillary assembly upon the influence of thermal treatment, and further reveal fine-details of the optical samples. Finally, conclusive remarks are drawn that the fibrillary structures doped with the NPs exhibit an increasing degree of unique orthogonality. As the temperature rises, utter deformation of the dendritic structures of fibrillary assemblies at 70 degrees C was found, and NIR laser-irradiated CsWO3 NPs have been demonstrated to be useful in topically destructing pre-assembled LAFs, which may be conducive to the future development of neurodegenerative therapeutic techniques.
Memory effect in nematic phase of liquid crystal doped with magnetic and non-magnetic nanoparticles
(2019-05-15)
Gdovinova, Veronika
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Tomasovicova, Natalia
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Jeng, Shie-Chan
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Zakutanska, Katarina
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Kula, Przemyslaw
The dielectric properties of SiO2 nanoparticles and their mixture with Fe3O4 nanoparticles in 5CB liquid crystal were studied by using capacitance-voltage measurements. The prepared colloidal systems exhibited a soft memory effect detected by dielectric hysteresis in nematic phase at ambient temperature. In case of homogeneous SiO2 nanoparticles as dopants, the doped liquid crystal showed the improvement of the effect, sensitive to increasing the nanoparticles concentration. The presence of magnetic nanoparticles caused decreasing the memory effect that was concentration dependent. Additional studies revealed that the temperature erased the observed effect as well as the fact that the different oriented magnetic field changed the magnitude of memory effect. The potential application of these composites leads to a fabrication of non-volatile and low power electro-optical memory devices suitable for information storage applications. (C) 2019 Elsevier B.V. All rights reserved.