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Abstract: This study aimed to obtain functional viscose textiles based on chitosan coatings with improved antibacterial properties and washing durability. For that reason, before functionalization with chitosan/zinc nanoparticles (NCH+Zn), the viscose fabric was modified by nonthermal gas plasma of dielectric barrier discharge (DBD) to introduce into its structure functional groups suitable for attachment of NCH+Zn. NCH+Zn were characterized by measurements of hydrodynamic diameter and zeta potential and AFM. DBD-plasma-modified and NCH+Zn-functionalized fabrics were characterized by zeta potential measurements, ATR-FTIR spectroscopy, the calcium acetate method (determination of content of carboxyl and aldehyde groups), SEM, breaking-strength measurements, elemental analysis, and ICP-OES. Their antibacterial activity was determined under dynamic contact conditions. In addition to SEM, the NCH+Zn distributions on viscose fabrics were also indirectly characterized by measuring their absorbent capacities before and after functionalization with NCH+Zn. Washing durability was monitored through changes in the zeta potential, chitosan and zinc content, and antibacterial activity after 1, 3, and 5 washing cycles. The obtained results showed that DBD plasma modification contributed to the simultaneous improvement of NCH+Zn sorption and antibacterial properties of the viscose fabric functionalized with NCH+Zn, and its washing durability, making it suitable for the production of high-value-added medical textiles.
Keywords: medical textiles, antibacterial properties, viscose, chitosan/zinc nanoparticles, dielectric barrier discharge
Published in DKUM: 26.03.2025; Views: 0; Downloads: 2
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Abstract: The development of new multicomponent nanoparticles is gaining increasing importance due to their specific functional properties, i.e., synthesised new complex concentrated nanoparticles (CCNPs) in the form of powder using ultrasonic spray pyrolysis (USP) and lyophilisation from the initial cast Ag20Pd20Pt20Cu20Ni20 alloy, which was in the function of the material after its catalytic abilities had been exhausted. Hydrometallurgical treatment was used to dissolve the cast alloy, from which the USP precursor was prepared. As a consequence of the incomplete dissolution of the cast alloy and the formation of Pt and Ni complexes, it was found that the complete recycling of the alloy is not possible. A microstructural examination of the synthesised CCNPs showed that round and mostly spherical (not 100%) nanoparticles were formed, with an average diameter of 200 nm. Research has shown that CCNPs belong to the group with medium entropy characteristics. A mechanism for the formation of CCNPs is proposed, based on the thermochemical analysis of element reduction with the help of H2 and based on the mixing enthalpy of binary systems.
Keywords: complex concentrated nanoparticles, ultrasonic spray pyrolysis, lyophilisation, characterization, formation mechanism
Published in DKUM: 24.03.2025; Views: 0; Downloads: 2
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Abstract: The report shows the strong impact of fullerene C60 nanoparticles on phase transitions and complex dynamics of rod-like liquid crystal dodecylcyanobiphenyl (12CB), within the limit of small concentrations. Studies were carried out using broadband dielectric spectroscopy (BDS) via the analysis of temperature dependences of the dielectric constant, the maximum of the primary loss curve, and relaxation times. They revealed a strong impact of nanoparticles, leading to a ~20% change of dielectric constant even at x = 0.05% of C60 fullerene. The application of the derivative-based and distortion-sensitive analysis showed that pretransitional effects dominate in the isotropic liquid phase up to 65 K above the clearing temperature and in the whole Smectic A mesophase. The impact of nanoparticles on the pretransitional anomaly appearance is notable for the smectic–solid phase transition. The fragility-based analysis of relaxation times revealed the universal pattern of its temperature changes, associated with scaling via the “mixed” (“activated” and “critical”) relation. Phase behavior and dynamics of tested systems are discussed within the extended Landau–de Gennes–Ginzburg mesoscopic approach.
Keywords: nanoparticles, liquid crystals, soft materials, fullerenes, dielectric spectroscopy, phase transitions, dynamics
Published in DKUM: 10.03.2025; Views: 0; Downloads: 3
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Abstract: This review provides a comprehensive Life Cycle Assessment (LCA) of a cosmetic cream to assess the environmental impacts throughout its entire life cycle, from raw material extraction to disposal, using the methodology according to international standards. The LCA was performed using the OpenLCA 2.0.1 software, with data from the Ecoinvent 3.8 database and relevant literature. The assessment focused on multiple impact categories, including climate change, acidification, eutrophication (freshwater, marine and terrestrial), ecotoxicity (freshwater), human toxicity (cancer and non-cancer), ionizing radiation, land use, ozone depletion, photochemical ozone formation, resource use (fossils, minerals and metals), and water use. The LCA of a cosmetic cream containing gold nanoparticles revealed significant environmental impacts across critical categories. The total climate change potential was 2596.95 kg CO2 eq., driven primarily by nanoparticle synthesis (60.7%) and electricity use (31.9%). Eutrophication of freshwater had the highest normalized result (3.000), with nanoparticle synthesis contributing heavily, indicating the need for improved wastewater treatment. The resource use (minerals and metals) scored 1.856, while the freshwater ecotoxicity reached 80,317.23 CTUe, both driven by the nanoparticle production. The human toxicity potentials were 1.39 × 10−6 CTUh (cancer) and 7.45 × 10−5 CTUh (non-cancer), linked to emissions from synthesis and energy use. The LCA of the cosmetic cream revealed several critical areas of environmental impact. The most significant impacts are associated with gold nanoparticle synthesis and electricity use. Addressing these impacts through optimized synthesis processes, improved energy efficiency, and alternative materials can enhance the product’s sustainability profile significantly.
Keywords: life cycle assessment, cosmetic cream, environmental impacts, gold nanoparticles
Published in DKUM: 17.12.2024; Views: 0; Downloads: 15
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Abstract: The derivatization of the polysaccharide dextran with N-protected amino acids (Boc-L-Phenylalanine, BocGlycine, Boc-L-Cysteine, and Boc-L-Cysteine-S-Trt) and peptides (Boc-L-DiPhenylalanine, Boc DiGlycine, and 2,5-diketopiperazine) as the basis for biomaterial preparation is presented in this Doctoral Dissertation. Such prepared dextran derivatives are intended to mimic the proteoglycan complex (PGs), one of the most important structural and functional biomacromolecules in the extracellular matrix (ECM) of tissue. Nowadays, developments in biomaterials are focusing increasingly on the preparation and use of biomimetic molecular structures to achieve positive results in tissue engineering (TE) and drug delivery. Designing and synthesizing these biomimetic materials, however, requires sophisticated chemical and material preparation methods, knowledge that is, currently, unexplored. In this work, we developed a suitable procedure for dextran derivatization, and investigated the most optimal reaction or deprotection conditions (temperature and time) and isolation/purification methods. The structures of the obtained BocPhe-Dex, BocGly-Dex, BocCys-Dex, and BocSTLC-Dex were analyzed with FTIR, NMR, SEC-MALS, and EA. The results showed that dextran derivatization was successful in all cases except in the case of dextran derivatization with BocCys. Investigation of the effect of the derivatization conditions and purification on the stability, purity, and other important chemical and physical properties of the obtained product, showed that the temperature and time of derivatization do not have a bigger effect on the products' properties, while the purification method, on the other hand, has. Its effect is visible in the product's purity and mass yields of products prepared under the same reaction conditions. Derivatization of dextran with peptides (Boc-L-DiPhenylalanine, BocDiGlycine, and 2,5-diketopiperazine) was performed using the CDI coupling agent or Amberlite-IR 120 as a catalyst. The products were analyzed with FTIR and 1H and 13C NMR. The results showed successful dextran derivatization in the case of BocDiPhenylalanine and BocDiGlycine, while, in the case of 2,5-diketopiperazine, a reaction covalent bond with the dextran was not confirmed. BocPhe-Dex and BocSTLC-Dex were selected as the most optimal amino acid-dextran derivatives for further preparation of 3D formulations in the shape of nanoparticles (NPs). Nanoparticles were prepared with the emulsion/solvent evaporation method from the obtained BocPhe-Dex and BocSTLC-Dex products (prepared in the first stage of this Doctoral Dissertation). SEM analysis showed that the prepared NPs were homogeneous and nicely spherical, with an average dry diameter of 325 ± 118 nm in the case of BocSTLC-Dex, and 1039 ± 382 nm in the case of NPs prepared from BocPhe-Dex. All the prepared NPs retained their proper spherical shape and stability during the acidic treatment, and so confirmed their potential for further functionalization and applications for drug delivery. The BocSTLC-Dex NPs were also evaluated with cell viability tests, which showed that the prepared NPs were not cytotoxic, one of the most important characteristics for the drug delivery applications of NPs. This work serves as a basis for further studies on the derivatization of polysaccharides with amino acids and peptides, and their application in tissue engineering or drug delivery.
Keywords: Amino Acid-Dextran derivatives, Peptide-Dextran derivatives, Proteoglycan complex, 3D formulation, Nanoparticles, Drug delivery
Published in DKUM: 18.10.2024; Views: 0; Downloads: 34
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