2024-07-27
00:02 |
Book of Abstracts and Programme
Beneš, Hynek ; Starý, Zdeněk
The Book of Abstracts and Programme contains time order and the summaries of all the contributions to the international conference “Polymers for Sustainable Future 2024” was organized simultaneously as the 85th Prague Meeting on Macromolecules (PMM) and 11th Conference on Green Chemistry and Nanotechnologies in Polymeric Materials. The participants presented 84 lectures and 91 posters.
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2024-06-02
00:00 |
Surfactant-free silver nanofluids as liquid systems with neuromorphic potential
Nikitin, D. ; Biliak, K. ; Lemke, J. ; Protsak, M. ; Pleskunov, P. ; Tosca, M. ; Ali-Ogly, S. ; Červenková, V. ; Adejube, B. ; Bajtošová, L. ; Černochová, Zulfiya ; Prokeš, J. ; Křivka, I. ; Biederman, H. ; Faupel, F. ; Vahl, A. ; Choukourov, A.
Neuromorphic engineering is a rapidly developing branch of science that aims to implement the unique attributes of biological neural networks in artificial devices. Most neuromorphic devices are based on the resistive switching effect, which involves changing the device’s conductivity in response to an external electric field. For instance, percolating nanoparticle (NP) networks produced by gas aggregation cluster sources (GAS) show collective spiking behavior in conductivity reminiscent of brain-like dynamics. Nevertheless, the problem of dynamic spatial reconfiguration in solid-state neuromorphic systems remains unsolved. Herein, novel nanofluids with resistive switching properties are proposed as neuromorphic media. They are produced by depositing silver NPs from GAS into vacuum-compatible liquids (paraffin, silicon oil, and PEG) without the use of surfactants or other chemicals. When the electric field is applied between two electrodes, the migration of NPs toward biased electrode is detected in all liquids. The electrophoretic nature of the NP movement was proved by means of ζ-potential measurements. Such movement led to the self-assembly of NPs in conductive paths connecting the electrodes and, as a result, to resistive switching. The electrical response was strongly dependent on the dielectric constant of the base liquid. The Ag-PEG nanofluid demonstrated the best switching performance reproducible during several tens of current-voltage cycles. The growth of flexible and reconfigurable conductive filaments in nanofluids makes them suitable media for potential realization of 3D neural networks.
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2024-06-02
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Temoporfin-conjugated upconversion nanoparticles for NIR-induced photodynamic therapy of pancreatic cancer
Shapoval, Oleksandr ; Větvička, D. ; Kabešová, M. ; Engstová, Hana ; Horák, Daniel
Photodynamic therapy (PDT), a clinically approved cancer treatment strategy, has the potential to cure pancreatic cancer with minimal side effects. PDT primarily uses visible wavelengths to directly activate hydrophobic photosensitizers, which may be insufficient for deep-seated cancer cells in clinical practice due to poor penetration. Upconversion nanoparticles (UCNPs) serve as an indirect excitation source to activate photosensitizers (PSs) in the NIR region, overcoming the limitations of molecular PSs such as hydrophobicity, non-specificity, and excitation in the UV/Vis region. Here, monodisperse upconversion NaYF4:Yb3+, Er3+, Fe2+ nanoparticles (UCNPs) have been surface-engineered with poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) and temoporfin (mTHPC), a clinically used PDT prodrug, for near-infrared (NIR) light-triggered PDT of pancreatic cancer. The incorporation of Fe2+ ions into the particles increased the fluorescence intensity in the red region matching the activation wavelength of mTHPC. Covalent binding of mTHPC to the surface of UCNP@PMVEMA particles provided colloidally stable conjugates enabling generation of singlet oxygen. In vitro cytotoxicity and photodynamic activity of the particles were evaluated using INS-1E rat insulinoma and Capan-2 and PANC-01 human pancreatic adenocarcinoma cell lines. The PDT efficacy of UCNP@PMVEMA-mTHPC conjugates after irradiation with 980 nm NIR light was tested in vivo in a pilot study on Capan-2 human pancreatic adenocarcinoma growing subcutaneously in athymic nude mice. The intratumoral administration of the nanoconjugates significantly hindered tumor growth and demonstrated promising PDT efficacy against human pancreatic cancer.
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2023-02-12
22:32 |
Novel embedding resins for 3D-SEM II
Šlouf, Miroslav ; Pavlova, Ewa ; Strachota, Beata ; Strachota, Adam ; Nebesářová, Jana ; Týč, Jiří ; Krzyžánek, Vladislav ; Skoupý, Radim
Research report for Thermo Fisher Scientific s. r. o., based on common project awarded by TA CR (program: National center of competence, TN01000008).
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2023-01-29
22:31 |
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2022-11-20
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2022-10-23
00:01 |
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2022-09-28
00:47 |
Degradation of polycaprolactone electrospun materials - methods of analysis
Havlíčková, K. ; Řezanka, M. ; Kobera, Libor ; Kuželová Košťáková, E. ; Lukáš, D. ; Jenčová, V.
Biodegradable electrospun materials are widely used for medical application. Polycaprolatone is polymer suitable for electrospinning technology and is very often used to create nanofibrous scaffolds for tissue engineering. The time to disintegration or biodegradation of such materials is very important here. However, testing is not entirely easy. It is not possible to create exactly body-like conditions in vitro. Moreover, it is not easy to find suitable analytical methods that would show exactly what happens in the nanofibrous polycaprolactone electrospun samples at certain stages of degradation, ie how the internal structure of decaying nanofibers changes. This paper describes the traditional use of methods for testing polycaprolatone nanofibers by enzymatically catalysed degradation. Morphological changes are studied using scanning electron microscope images. However, it also offers a non-traditional analysis of polycaprolactone electrospun materials using the ssNMR method.
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2022-09-28
00:47 |
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2019-07-25
09:14 |
Career in Polymers XI, Book of Abstracts
Kobera, Libor
The book of abstracts contains the summaries of all the contributions to the Career in Polymers XI., workshop organized by the Institute of Macromolecular Chemistry AS CR, in Prague, 28-29 June, 2019. This meeting was organized under the auspices of UNESCO/IUPAC course in Polymer Science, and supported by Strategy AV21.
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