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Now showing items 1 - 16 of 18

  • Polysaccharide Based Wound Care Materials

    Maver, Tina   Maver, Uros   Pivec, Tanja   Kurecic, Manja   Persin, Zdenka   Kleinschek, Karin Stana  

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  • Emerging Techniques in the Preparation of Wound Care Products

    Maver, Tina   Maver, Uros   Pivec, Tanja   Kurecic, Manja   Persin, Zdenka   Kleinschek, Karin Stana  

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  • Active Substances for Acceleration of Wound Healing

    Maver, Tina   Maver, Uros   Pivec, Tanja   Kurecic, Manja   Persin, Zdenka   Kleinschek, Karin Stana  

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  • Advanced Wound Care

    Maver, Tina   Maver, Uros   Pivec, Tanja   Kurecic, Manja   Persin, Zdenka   Kleinschek, Karin Stana  

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  • Bio-nanofibrous mats as potential delivering systems of natural substances

    Persin, Zdenka   Ravber, Matej   Kleinschek, Karin Stana   Knez, Zeljko   Skerget, Mojca   Kurecic, Manja  

    Considering the increasing resistance of numerous bacteria to antibiotics, a novel wound dressing material was developed with naturally acquired olive leaf extract, which shows not only good antimicrobial activity, but also very good antioxidant activity. Besides that, the leaves are treated as waste in agriculture, giving an impact on waste management. An environmentally friendly procedure, electrospinning, was used for the first time to prepare polysaccharide nanofibrous mats with incorporated olive leaf extract, with the unique property of releasing the active phenolic components in a prolonged manner over 24 hours. The developed electrospun mats were characterized using scanning electron microscopy, high-performance liquid chromatography and ultraviolet-visible spectroscopy for determination of free radical scavenging activity by 2,2-diphenyl-1-picrylhydrazyl, antimicrobial testing and release kinetics. Antimicrobial tests have shown that electrospun mats with olive leaf extract achieve reduction towards the tested microorganisms: Staphylococcus aureus (G+), Escherichia coli (G-), Enterococcus faecalis (G+) and Pseudomonas aeruginosa (G-), while the high antioxidant activity of olive leaf extract was preserved during the electrospinning procedure. Release of olive leaf extract from electrospun mats was mathematically modeled, and the release kinetics evaluation indicates the appropriateness of the Korsmeyer-Peppas model for fitting the obtained results of release ability due to erosion of polysaccharide nanofiber mats.
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  • Novel cellulose based materials for safe and efficient wound treatment.

    Persin, Zdenka   Maver, Uros   Pivec, Tanja   Maver, Tina   Vesel, Alenka   Mozetic, Miran   Stana-Kleinschek, Karin  

    The present study aims at achieving effects of improved hydrophilicity and microorganism inhibition, which are rarely simultaneously present in wound dressings. Viscose fibers in their non-woven form were modified using two different pathways. Effects of a two-step procedure, i.e. alkaline or oxygen plasma treatment followed by the attachment of silver chloride nanoparticles were compared to a one-step procedure, i.e. ammonium plasma treatment, which results in both desired material characteristics simultaneously. The surface properties of untreated and differently modified cellulose samples were analyzed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), in vitro silver release, and hydrophilicity measurements. The treatment effect on antimicrobial activity was determined by the AATCC 100-1999 standard test. In light of the introduced wound dressing preparation procedures and the desired wound dressing characteristics, the effectiveness of the used procedures was evaluated. Antimicrobial activity was proven against all Gram negative bacteria, while the Gram positive bacteria survive the as-prepared samples. Hydrophilicity was proven to be excellent using both preparation procedures. The mentioned results prove the potential of the used procedures and encourage future developments toward the clinical proof of concept. Copyright =C2=A9 2013 Elsevier Ltd. All rights reserved.
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  • Modification of cellulose non-woven substrates for preparation of modern wound dressings

    Pivec, Tanja   Persin, Zdenka   Kolar, Mitja   Maver, Tina   Dobaj, Andreja   Vesel, Alenka   Maver, Uros   Stana-Kleinschek, Karin  

    Different ways are presented of modifying cellulosic non-woven substrates, which can serve as potential wound dressings with satisfactory antimicrobial and hydrophilic properties. For safe attachment of silver particles without a measurable release from the used materials, a sol-gel derived process was used. Alkaline and oxygen plasma treatments were used to improve the hydrophilicity of the materials. Their efficiency was determined by measuring contact angles and water retention values. Scanning electron microscopy (SEM) was used for determination of sample morphology prior to and after treatment. The efficiency of silver attachment and activity was evaluated by invitro release studies and antimicrobial tests. Atomic force microscopy (AFM) and SEM, combined with dynamic light scattering, were used for determination of silver particle size. Additionally, we evaluated the influence of treatment on technological parameters, important for application performance, i.e. mechanical properties and air permeability.
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  • Improvement of Chitosan Adsorption onto Cellulosic Fabrics by Plasma Treatment

    Zemljic, Lidija Fras   Persin, Zdenka   Stenius, Per  

    Oxygen plasma treatment was applied in order to improve the adsorption of chitosan onto viscose fabric. Modification of the surface and adsorption of chitosan was monitored by determination of XPS spectra, determination of contact angles from rates of water imbibition, and conductometric titration. The plasma treatment resulted in hydrophilization of the surfaces through oxidation. The hydrophilic surfaces were stable for at least 24 h. The treatment also yielded binding sites that resulted in over 20% increase of the amount of chitosan adsorbed over that adsorbed on nontreated fabric. Layers of chitosan adsorbed after plasma treatment were substantially more active as antimicrobial agents than those on nontreated surfaces.
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  • Carboxyl groups in pre-treated regenerated cellulose fibres

    Zemljic, Lidija Fras   Persin, Zdenka   Stenius, Per   Kleinschek, Karin Stana  

    The influence of peroxide bleaching and slack-mercerization on the amount of acidic groups in regenerated fibres (viscose, modal and lyocell) were studied. Conductometric titration was used to determine the total content of acidic carboxylic groups. Polyelectrolyte titration was used for surface and total charge determination, and to obtain information about the charge distribution and accessibilities of charged groups. Changes in fibre crystallinity to pre-treatment processes were characterized using iodine sorption (Schwertassek method) and correlated to treatments and the amount of carboxylic groups. For all three types of fibres the amount of accessible carboxyl groups was lowered by an increase in the degree of crystallinity. Bleaching with hydrogen peroxide causes some oxidative cellulose damage and, therefore, a larger amount of carboxyl groups (presumably formed at the end of cellulose chains). Slack-mercerization did not significantly change the total amount of acidic groups in the fibres, but their accessibility to cationic polyelectrolytes, in particular to polymers with high molecular weight was substantially lowered.
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  • Chitosan nanoparticles as a potential drug delivery system attached to viscose cellulose fibers

    Ristic, Tijana   Zabret, Andrej   Zemljic, Lidija Fras   Persin, Zdenka  

    Chitosan and its water-soluble N,N,N-trimethyl derivative were attached to cellulose fibers in the form of nanoparticle dispersions. The attachment of the chitosan nanoparticles to the fiber surface was studied by evaluation of the quantity of chitosan amino groups using a conventional spectrophotometric method supported by X-ray photoelectron spectroscopy. The desorption kinetics of the chitosan nanoparticles from the fiber surface was also examined indirectly by the spectrophotometric method. Additionally, a model drug was incorporated into the optimal chitosan nanoparticles for subsequent attachment to fibers to create a potential fibrous drug delivery system aimed at gynecological use, i.e., tampons as antimicrobial agents themselves or as drug reservoirs.
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  • Characterisation of surface properties of chemical and plasma treated regenerated cellulose fabric

    Persin, Zdenka   Vesel, Alenka   Kleinschek, Karin Stana   Mozetic, Miran  

    The aim of this research work was to study the surface properties and sorption characteristics of differently treated regenerated cellulose fabrics. Surface modifications of viscose, modal and lyocell samples caused by using standard chemical pre-treatment procedures were compared to an alternative activation procedure by applying low pressure oxygen plasma treatment. The elemental chemical composition of the modified fabric surfaces was investigated using X-ray photoelectron spectroscopy (XPS), while hydrophilic/hydrophobic properties were evaluated by determining the water contact angles, as well as thoroughly analysed using Owens-Wendt surface energy (SFE) and surface polarity investigations. Standard chemical and also plasma treatments changed the surface chemistry of cellulose. Bleaching and alkaline treatments increased the surface carboxylic acid content by approximately 4.8% while plasma treatment increased it by approximately 9.7%. As a consequence, higher hydrophilicity arises as proved by water contact angle decrease; i.e. 24% (61 degrees) after standard chemical treatments and 70% (20 degrees) after plasma treatment. Both chemical treatments increase the SFE and polar components, while the reduction of dispersive components was less pronounced. The oxygen activation treatment has the greatest influence on the SFEs of the samples as well as on polarity of the samples.
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  • The evaluation of the in vitro antimicrobial properties of fibers functionalized by chitosan nanoparticles

    Ristic, Tijana   Persin, Zdenka   Kuncic, Marjetka Kralj   Kosalec, Ivan   Zemljic, Lidija Fras  

    In this work, chitosan (CS) and its water-soluble derivatives, N,N,N-trimethyl chitosans (TMC), were used in the form of solution and nanoparticles dispersions (CSNP) as an adsorbate for cellulose fibers in order to obtain bioactive functionality of fibers aimed toward use in tampons. To examine the usability of bioactive tampons it is extremely important to provide detailed information about tampons' antimicrobial capacity regarding pathogen microorganisms (MOs), as well as for those responsible for healthy flora such as Lactobacillus sp. Thus, evaluation of the in vitro antimicrobial properties of functionalized fibers was performed in detail using the standard shake-flask test method (ASTM E2149) and "time-kill" method (non-standard method) against S. aureus, E. coli, and C. albicans. Both methods were compared. Susceptibility of Lactobacillus sp. to coated fibers was tested as well. Additionally, cytotoxic properties of fibers were evaluated as a further indicator of safety aspect of tampons functionalized by CS and TMC. The results show that specific functionalization of tampons using CS nanoparticles could improve tampon antimicrobial activity and offer a safety upgrade for the regular feminine cotton tampon, providing an attractive feature.
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  • The study of plasma's modification effects in viscose used as an absorbent for wound-relevant fluids

    Persin, Zdenka   Devetak, Miha   Drevensek-Olenik, Irena   Vesel, Alenka   Mozetic, Miran   Stana-Kleinschek, Karin  

    Extreme non-equilibrium oxygen plasma was used for the deep functionalisation of viscose materials used for the healing of chronic wounds. Those thermal effects, which usually appear during plasma treatment due to the influence of charged particles, were avoided effectively by using electrode-less discharge at a very low power density of 25 W/l volume. A huge flux of neutrally reactive atoms at room temperature of 3 x 10(23) m(-2) S-1, allowed for the effective diffusion of O-atoms into inter-fibril space and thus the activation of fibrils throughout the non-woven materials. Apart from the standard Wilhelmy balance and pedant drop method for determining the absorption dynamics on a macroscopic scale, optical polarisation microscopy was applied for studying the microscopic effects. The sorption characteristics were determined for saline solution, exudate, and blood and the results showed a dramatic improvement. Focusing on hydrophobic recovery prevention, the modified samples were stored for 10 days in air, nitrogen, and argon atmospheres. Some ageing effects occurred, whilst the absorption properties were independent of the storage atmosphere. (C) 2013 Elsevier Ltd. All rights reserved.
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  • Utilization of optical polarization microscopy in the study of sorption characteristics of wound dressing host materials.

    Devetak, Miha   Persin, Zdenka   Stana-Kleinschek, Karin   Maver, Uros  

    Polarization microscopy was used for evaluation of kinetics of diclofenac sorption in three different wound dressing materials. The sorption kinetics can be evaluated by radii change and intensity of the light traveling through the fiber. The most frequently used host materials for drugs in wound dressings are alginate, polyesters such as polyethylene terephthalate, and viscose. We studied sorption of diclofenac as an example drug. Effective, but rather simple in vitro simulation of diclofenac sorption gives insight into the applicability of the mentioned materials for development of wound healing materials. =20
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  • Morphology of polysaccharide blend fibers shaped from NaOH, N-methylmorpholine-N-oxide and 1-ethyl-3-methylimidazolium acetate

    Persin, Zdenka   Stana-Kleinschek, Karin   Reischl, Martin   Ribitsch, Volker   Bohn, Andreas   Fink, Hans-Peter   Meister, Frank  

    The aim of this study was to find newly structured biopolymer blends bearing those adjustable features able to produce innovative materials. Apart from cellulose derivatives (cellulose carbamate and carboxymethyl cellulose), mannans (guar gum, locust bean gum, and tragacanth gum), xylan, starch (cationized), iota-carrageenan, and xanthan were chosen as blend polysaccharides for cellulose as matrix. In order to study their integration into the cellulose skeleton, fibers were shaped from three different solvents: NaOH by a special wet-spinning process, as well as N-methylmorpholine-N-oxide (NMMO) and 1-ethyl-3-methylimidazolium acetate (EMIMac) via Lyocell technology. The structure and morphologies of the fibers were analyzed by X-ray wide-angle scattering and atomic force microscopy. Hydrophilic/hydrophobic properties were determined by means of a contact angle, as well as moisture content and water retention values, while the surface properties throughout zeta-potential measurements. Being very different processes, the wet spinning in NaOH solution and the dry-wet spinning are deeply impacted by the types of solvent and polysaccharide. The X-ray results for NMMO fibers revealed the highest orientation compared with EMIMac having the lowest orientation of NaOH fibrous types. AFM images also show the lowest surface roughnesses for NMMO and EMIMac fibers. The moisture content and water retention values support these trends, while the water contact angle results show insignificant differences between the samples from EMIMac and NaOH, even though the values calculated for NMMO fibers were the lowest.
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  • Medical textiles based on viscose rayon fabrics coated with chitosan-encapsulated iodine:antibacterial and antioxidant properties

    Zemljic, Lidija Fras   Persin, Zdenka   Sauperl, Olivera   Rudolf, Andreja   Kostic, Mirjana  

    Adsorption of chitosan nanoparticles with embedded iodine was implemented onto pristine and oxidized cellulose viscose fabrics in order to introduce antimicrobial and antioxidative functionalization. The adsorption capacity, charging behavior and electrokinetic response of differently functionalized viscose at different pH values were analyzed by determining their zeta potential. Desorption studies, besides zeta potential measurements, were supported by polyelectrolyte titration. Finally, the antimicrobial properties were evaluated by the standard ASTM E2149 method, whilst antioxidative properties were determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation decolorization assay. It was found that the oxidation of viscose fabrics further modified by chitosan-iodine nanoparticles dispersion was a very promising functionalization process, providing good coating stability along with antimicrobial and antioxidant properties.
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