1. Obtaining medical textiles based on viscose and chitosan/zinc nanoparticles with improved antibacterial properties by using a dielectric barrier dischargeMatea Korica, Ana Kramar, Zdenka Peršin Fratnik, Bratislav M. Obradović, Milorad Kuraica, Biljana Dojčinović, Lidija Fras Zemljič, Mirjana M. Kostić, 2022, original scientific article 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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2. Economical chemical recycling of complex PET waste in the form of active packaging materialJulija Volmajer Valh, Dimitrije Stopar, Ignacio Selaya Berodia, Alen Erjavec, Olivera Šauperl, Lidija Fras Zemljič, 2022, original scientific article Abstract: Since millions of tons of packaging material cannot be recycled in conventional ways, most
of it ends up in landfills or even dumped into the natural environment. The researched methods
of chemical depolymerization therefore open a new perspective for the recycling of various PET
materials, which are especially important for packaging. Food preservative packaging materials
made from PET plastics are complex, and their wastes are often contaminated, so there are no
sophisticated solutions for them in the recycling industry. After integrating the biopolymer chitosan,
which is derived from natural chitin, as an active surface additive in PET materials, we discovered
that it not only enriches the packaging material as a microbial inhibitor to reduce the bacteria
Staphylococcus aureus and Escherichia coli, thus extending the shelf life of the contained food, but also
enables economical chemical recycling by alkaline or neutral hydrolysis, which is an environmentally
friendly process. Alkaline hydrolysis at a high temperature and pressure completely depolymerizes
chitosan-coated PET packaging materials into pure terephthalic acid and charcoal. The products
were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance
spectroscopy, and elemental analysis. The resulting reusable material represents raw materials
in chemical, plastic, textile, and other industries, in addition to the antimicrobial function and
recyclability itself.
Keywords: chitosan, active packaging, PET, recycling, reusability
Published in DKUM: 26.03.2025; Views: 0; Downloads: 5
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3. Energy demand distribution and environmental impact assessment of chitosan production from shrimp shellsFilipa A. Vicente, Robert Hren, Uroš Novak, Lidija Čuček, Blaž Likozar, Annamaria Vujanović, 2024, original scientific article Abstract: Step towards resilience and sustainability through exploring renewable biomass and waste streams to produce higher-added value products and energy is among key aspects for closing the loops, saving resources, and reducing the resource and emission footprints. In that respective, crustacean shells waste can offer rich spectre of valuable compounds such as proteins, chitin, carotenoids. This waste is produced in large quantities worldwide, thus allowing for commercial valorisation. An overview of technologies is undertaken for more sustainable and environmentally friendly chitosan production via chitin isolation and conversion and compared to the conventional processes. Furthermore, an assessment of the environmental burden and energy demand distribution for conventional and more sustainable alternative processes was performed, based on lab-scale experimental data. Three different chitin extraction routes and three distinct chitosan conversion processes were considered and compared for their greenhouse gas footprint, abiotic depletion, acidification, eutrophication and other potentials. Finally, the energy demand distribution was analysed considering electricity production patterns from three European countries, Slovenia, Portugal and Norway. The results showed that alternatives 3-A and 3-B (conventional eco-solvents - conventional deacetylation with 40 % and 50 % NaOH) generate the lowest environmental burden (184 g CO2 eq./g chitosan). Electricity was the main hotspot of the processes, used either for extraction, plasma treatment or deacetylation. The sensitivity analysis proved that the Norwegian electricity mix has the lowest environmental impact (4.2 g CO2 eq./g chitosan). This study highlights the impact of blue biorefineries by transforming marine waste to valuable biopolymers such as chitin and chitosan.
Keywords: shrimp shells waste, blue biorefinery, value-added products, chitosan, sustainable production, comparative environmental assessment
Published in DKUM: 08.01.2025; Views: 1; Downloads: 3
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4. Nanodelci hitozana kot potencialni protimikrobni premazZdenka Peršin Fratnik, Uroš Maver, Metod Kolar, Olivera Šauperl, Lidija Fras Zemljič, Boštjan Vihar, 2024, original scientific article Abstract: Namen študije je bil ugotoviti protimikrobno učinkovitost hitozanskih nanodelcev v primerjavi s hitozansko raztopino in sled temu njihovo učinkovito rabo na medicinskih tekstilnih materialih.
Keywords: chitosan, nanoparticles, antimicrobial activity, coatings, medical textile materials
Published in DKUM: 07.01.2025; Views: 0; Downloads: 24
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5. A method for the immobilization of chitosan onto urinary cathetersAlenka Vesel, Nina Recek, Rok Zaplotnik, Albert Kurinčič, Katja Kuzmič, Lidija Fras Zemljič, 2022, original scientific article Abstract: A method for the immobilization of an antibacterial chitosan coating to polymeric urinary medical catheters is presented. The method comprises a two-step plasma-treatment procedure, followed by the deposition of chitosan from the water solution. In the first plasma step, the urinary catheter is treated with vacuum-ultraviolet radiation to break bonds in the polymer surface film and create dangling bonds, which are occupied by hydrogen atoms. In the second plasma step, polymeric catheters are treated with atomic oxygen to form oxygen-containing surface functional groups acting as binding sites for chitosan. The presence of oxygen functional groups also causes a transformation of the hydrophobic polymer surface to hydrophilic, thus enabling uniform wetting and improved adsorption of the chitosan coating. The wettability was measured by the sessile-drop method, while the surface composition and structure were measured by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Non-treated samples did not exhibit successful chitosan immobilization. The effect of plasma treatment on immobilization was explained by noncovalent interactions such as electrostatic interactions and hydrogen bonds.
Keywords: polymer, chitosan immobilization, adhesion, plasma-surface modification, biopolymers
Published in DKUM: 05.12.2024; Views: 0; Downloads: 3
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6. Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressingsMatea Korica, Katarina Mihajlovski, Tamilselvan Mohan, Mirjana M. Kostić, 2024, original scientific article Abstract: A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method.
Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPOoxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by
atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness),
functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water
vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan
nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density
ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2
, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 μm,
iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ±
0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03
to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight
loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor
transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in
physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus
aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films
could be effectively utilized as antibacterial wound dressings.
Keywords: TEMPO-oxidized chitosan nanoparticles, films, antibacterial activity, wound dressings
Published in DKUM: 11.09.2024; Views: 56; Downloads: 64
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7. Influence of cross-linkers on the wash resistance of chitosan-functionalized polyester fabricsTanja Pušić, Tea Bušac, Julija Volmajer Valh, 2024, original scientific article Abstract: This study investigates the wash resistance of polyester fabrics functionalized with chitosan,
a biopolymer known for its biocompatibility, non-toxicity, biodegradability and environmentally
friendly properties. The interaction of chitosan with synthetic polymers, such as polyester, often
requires surface treatment due to the weak natural affinity between the two materials. To improve
the interaction and stability of chitosan on polyester, alkaline hydrolysis of the polyester fabric was
used as a surface treatment method. The effectiveness of using cross-linking agents 1,2,3,4-butane
tetracarboxylic acid (BTCA) and hydroxyethyl methacrylate (HEMA) in combination with ammonium
persulphate (APS) to improve the stability of chitosan on polyester during washing was investigated.
The wash resistance of polyester fabrics functionalized with chitosan was tested after 1, 5 and
10 washes with a standard ECE detergent. Staining tests were carried out to evaluate the retention of
chitosan on the fabric. The results showed that polyester fabrics functionalized with chitosan without
cross-linkers exhibited better wash resistance than the fabrics treated with crosslinkers.
Keywords: polyster, functionalization, chitosan, cross-linkers, stability, washing
Published in DKUM: 10.09.2024; Views: 55; Downloads: 15
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8. Covalent modification of chitosan surfaces with a sugar amino acid and lysine analoguesTobias Dorn, Matjaž Finšgar, Karin Stana-Kleinschek, Tobias Alexander Steindorfer, Martin Simon Thonhofer, Tanja Wrodnigg, Rupert Kargl, 2024, original scientific article Abstract: This work explores the modifcation and characterization of chitosan thin flms as a model for functionalized polysaccharide
interfaces. The solid–liquid interface of oligo- and polysaccharides is crucial for various biological processes such as cell
adhesion and recognition. By covalent surface modifcation of the chitosan via amide formation with diferent small molecules containing carboxylic acids, e.g. specially designed glycoside hydrolase inhibitors, interactions with biomolecules and
living cells could potentially be controlled in the future. As a frst step towards this aim, three fuorescent compounds were
conjugated onto nanometric chitosan thin flms. The layers were analysed by fuorescence spectroscopy, X-ray photoelectron
spectroscopy, time-of-fight secondary ion mass spectrometry, and atomic force microscopy, to proof the covalent attachment
of the target molecules. By this analysis, a uniform and chemically stable covalent attachment of the target molecules on
the chitosan thin flms could be demonstrated under various conditions. This publication serves as a proof-of-concept-study
for further biofunctionalization, pattering, and interaction studies involving polysaccharide interfaces, glycosidase inhibitors, proteins, or living cells.
Keywords: carbohydrates, fluorescence spectroscopy, amino acid, chitosan, thin flm modifcation, C-Glycosides
Published in DKUM: 07.08.2024; Views: 127; Downloads: 19
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9. Exploring chitosan-plant extract bilayer coatings: Advancements in active food packaging via polypropylene modificationSaša Kaloper, Olivija Plohl, Sonja Smole Možina, Alenka Vesel, Vida Šimat, Lidija Fras Zemljič, 2024, original scientific article Abstract: UV-ozone activated polypropylene (PP) food films were subjected to a novel bilayer coating process involving primary or quaternary chitosan (CH/QCH) as the first layer and natural extracts from juniper needles (Juniperus oxycedrus; JUN) or blackberry leaves (Rubus fruticosus; BBL) as the second layer. This innovative approach aims to redefine active packaging (AP) development. Through a detailed analysis by surface characterization and bioactivity assessments (i.e., antioxidant and antimicrobial functionalities), we evaluated different coating combinations. Furthermore, we investigated the stability and barrier characteristics inherent in these coatings. The confirmed deposition, coupled with a comprehensive characterization of their composition and morphology, underscored the efficacy of the coatings. Our investigation included wettability assessment via contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), which revealed substantial enhancements in surface concentrations of elements and functional groups of CH, QCH, JUN, and BBL. Scanning electron microscopy (SEM) unveiled the coatings' heterogeneity, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) and CA profiling showed moderately compact bilayers on PP, providing active species on the hydrophilic surface, respectively. The coatings significantly reduced the oxygen permeability. Additionally, single-layer depositions of CH and QCH remained below the overall migration limit (OML). Remarkably, the coatings exhibited robust antioxidative properties due to plant extracts and exceptional antimicrobial activity against S. aureus, attributed to QCH. These findings underscore the pivotal role of film surface properties in governing bioactive characteristics and offer a promising pathway for enhancing food packaging functionality.
Keywords: chitosan, plant extracts, polypropylene, active packaging, surface characterization, bioactivity
Published in DKUM: 27.05.2024; Views: 241; Downloads: 21
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10. Slot‑die coating of cellulose nanocrystals and chitosan for improved barrier properties of paperYlenia Ruberto, Vera Vivod, Janja Juhant Grkman, Gregor Lavrič, Claudia Graiff, Vanja Kokol, 2024, original scientific article Abstract: Cellulose nanocrystals (CNCs) and chitosan (Cht) have been studied extensively for oxygen and water vapour barrier coatings in biodegradable, compostable or recyclable paper packaging. However, rare studies have been performed by using scalable, inexpensive, and fast continuous slot-die coating processes, and none yet in combination with fast' and high-throughput near-infrared (NIR) light energy drying. In this frame, we studied the feasibility of a moderately concentrated (11 wt%) anionic CNC and (2 wt%) cationic Cht coating (both containing 20 wt% sorbitol related to the weight of CNC/Cht), by using plain and pigment pre-treated papers. The effect of coating parameters (injection speed, dry thickness settings) were investigated on coating quantity (dry weight, thickness) and homogeneity (coverage), papers' structure (thickness, grammage, density), whiteness, surface wettability, barrier (air, oxygen and water vapour) properties and adhesion (surface strength). The coating homogeneity was dependent primarily on the suspensions' viscosity, and secondarily on the applied coating parameters, whereby CNCs could be applied at 1–2 times higher injection speeds (up to 80 mL/min) and versatile coating weights, but required a relatively longer time to dry. The CNCs thus exhibited outstanding air (4.2–1.5 nm/Pa s) and oxygen (2.7–1.1 cm3 mm/m2 d kPa) barrier performance at 50% RH and 22–33 g/m2 deposition, whereas on top deposited Cht (3–4 g/m2) reduced its wetting time and improved the water vapour barrier (0.23–0.28 g mm/m2 d Pa). The balanced barrier properties were achieved due to the polar characteristic of CNCs, the hydrophobic nature of Cht and the quantity of the applied bilayer coating that can provide sustainable paper-based packaging.
Keywords: paper, nanocellulose, chitosan, slot‑die coating, near-infrared (NIR) drying, barrier properties
Published in DKUM: 06.05.2024; Views: 227; Downloads: 18
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