OPTIMIRANJE PROCESNIH PARAMETROV IN SESTAVE FERMENTACIJSKEGA MEDIJA ZA PROIZVODNJO KEFIRANA IZ NARAVNIH KEFIRNIH ZRNTanja Pivec
, 2010, diplomsko delo
Opis: V diplomskem delu opisujemo potek določanja optimalnih procesnih parametrov in sestave fermentacijskega medija za proizvodnjo kefirana iz naravnih kefirnih zrn. Vse eksperimente smo opravljali v laboratorijskem šaržnem reaktorju (reakcijski kalorimeter RC1).
Eksperimentalni del diplomske naloge je bil sestavljen iz dveh delov. V prvem delu smo preučevali vpliv temperature fermentacije in vrtilne frekvence mešala oz. režima mešanja na prirast kefirnih zrn in proizvodnjo kefirana. Izvajali smo 24-urne fermentacije. Vrednosti procesnih parametrov, pri katerih smo dobili najvišji donos kefirana, smo uporabili v drugem delu eksperimentalnega dela, v katerem smo optimirali sestavo fermentacijskega medija. Pri tem smo preučili vpliv različnih vrst rastnih dodatkov (sladkorjev, dušikovih spojin in vitaminov) na prirast kefirnih zrn in proizvodnjo kefirana.
Uspešno smo povišali proizvodnjo kefirana z optimiranjem procesnih parametrov in dodatkom sladkorjev, medtem ko smo bili pri preučevanju vpliva dušikovih spojin in vitaminov na proizvodnjo kefirana manj uspešni.
Ključne besede: kefiran, kefirna zrna, optimiranje, procesni parametri, fermentacijski medij
Objavljeno: 13.09.2010; Ogledov: 1891; Prenosov: 139
Celotno besedilo (1,51 MB)
Binding silver nano-particles onto viscose non-woven using different commercial sol-gel proceduresTanja Pivec
, Zdenka Peršin
, Silvo Hribernik
, Tina Maver
, Mitja Kolar
, Karin Stana-Kleinschek
, 2012, izvirni znanstveni članek
Opis: The paper presents possible solution of Ag binding using commercial sol-gel systems which enable its low release into a wound, providing a good antimicrobial effect on those bacterial cultures that are most likely present in the wound. The influence of different sol-gel systems on the hydrophilic properties of carrier materials and the level of released silver has been studied. The results showed that sol-gel as binding-systems could provide proper hydrophilic properties of material, whilst binding silver strongly enough providing at the same time excellent antimicrobial activity of the treated viscose meterials.
Ključne besede: silver nano-particles, sol-gel, viscose non-woven, silver release, hydrophilicity, antimicrobial properties
Objavljeno: 01.06.2012; Ogledov: 1189; Prenosov: 28
Celotno besedilo (235,88 KB)
Sol-gel/Ag coating and oxygen plasma treatment effect on synthetic wound fluid sorption by non-woven cellulose materialZdenka Peršin
, Tanja Pivec
, Miran Mozetič
, Karin Stana-Kleinschek
, 2017, kratki znanstveni prispevek
Opis: Non-woven cellulose material was functionalized using two techniques, i.e. the coating with AgCl via sol-gel and oxygen plasma. The treatment effects were studied regarding the wound fluid adsorption potential using physiological saline, synthetic exudate and synthetic blood. Plasma treatment was most efficient since a significant improvement by absorbency rate and capacity was evident, less pronounced in case of synthetic blood. The combination of both treatments showed a similar trend, while the effects were less prominent, but still sufficient by managing fluid-associated as well as infected wounds.
Ključne besede: non-woven cellulose fabric, sol-gel, oxygen plasma, absorption, synthetic wound fluids
Objavljeno: 31.08.2017; Ogledov: 165; Prenosov: 44
Celotno besedilo (86,21 KB)
Polyurethanes for medical useTanja Pivec
, Majda Sfiligoj-Smole
, Petra Gašparič
, Karin Stana-Kleinschek
, 2017, pregledni znanstveni članek
Opis: Polyurethanes are synthetic copolymers containing urethane linkages in their complex chemical structure. They consist of three monomers: a diisocyanate, a polyol and a chain extender, which enables the synthesis of an endless number of polyurethanes with different physicochemical and mechanical properties. The physicochemical properties of various polyurethanes are largely dependent on the conformation of polyols, which may contain two or more different polyols, stabilisers, catalysts, liquids or solid additives and, in the case of foams, foaming agents. Depending on the structure of the polyols, i.e. the length of the chain, structure of the units (aliphatic or aromatic), ester or ether groups, or functionalisation by hydroxyl groups, polyurethanes may be flexible or rigid, and therefore suitable for various applications. In addition to the physical and chemical structure of polyurethanes, this review paper specifically addresses their use in medicine, particularly in wound dressings, tissue engineering scaffolds and drug delivery with nanoparticles and nanocapsules, and provides guidelines for the development of new biodegradable polyurethane materials.
Ključne besede: segmented polyurethanes, chemical structure, reactants, medical applications
Objavljeno: 03.10.2017; Ogledov: 229; Prenosov: 26
Celotno besedilo (383,90 KB)
Development of polymeric materials with rutin and polyrutin for healing of chronic leg ulcersTanja Pivec
, 2018, doktorska disertacija
Opis: In this work, the development of cellulose wound dressing materials with rutin (RU) and polyrutin (PR) for the healing of chronic leg ulcers is presented as a new approach of local treatment of this wound type. The flavonoid rutin is a known antioxidant substance of plant origin with wound healing promoting properties. Despite the proven beneficial properties of rutin, its potential application in wound healing is limited due to its low water solubility. This limitation can be overcome by polymerization of rutin into polyrutin. In this work an enzymatic polymerization of rutin in water without addition of organic solvents was performed to obtain a water-soluble polymer polyrutin. The chemical structure of rutin and polyrutin were investigated using UV-Vis spectroscopy, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, size-exclusion chromatography and potentiometric titrations. Biological activity related to a desired positive influence on chronic leg ulcers was investigated through the determination of the antioxidant activity, iron-chelation ability, cell viability, determination of cell proliferation and through use of the so called “scratch assay” to measure in vitro wound healing performance. Results indicate that rutin and polyrutin have a positive influence on the healing of chronic wounds. Rutin and polyrutin water dispersions at different pH and ionic strength were further characterised by means of dynamic light scattering in order to determine the size of particles and their pH dependent ζ-potential. The knowledge gained from these measurements aided the systematic interaction studies of rutin and polyrutin dispersions with cellulose-based surfaces via model and real wound healing systems. The model cellulose surfaces were thin films prepared by dissolution of trimethylsilyl cellulose in tetrahydrofuran, spin-coating of this solution on sensors of a quartz crystal microbalance (QCM-D) and subsequent regeneration of trimethylsilyl cellulose to cellulose with acid vapors. The influence of pH, salt concentration, and rutin/polyrutin concentration on the interaction with cellulose thin films was evaluated by means of a quartz crystal microbalance with dissipation. This knowledge was transferred to the application of the coatings on real wound healing systems i.e. cellulose non-wovens. The surface morphology was further characterised on model and real wound healing systems. The antioxidant activity and release kinetics were investigated for a real wound healing system, similar to the clinically used, cellulose based wound dressing materials. The main results showed that a higher solubility of polyrutin at low ionic strength contributes to the formation of continuous layers of polyrutin on cellulose surface, while the low solubility of rutin and reduced solubility of polyrutin at higher ionic strengths contribute to deposition of particles of rutin and polyrutin on the cellulose surface. The presence of particles on the surface of non-woven cellulose fibres led to a faster initial release of rutin and polyrutin. On the contrary, a continuous layer of the well soluble polyrutin contributes to a prolonged release. Namely, adsorption of the water soluble polyrutin at pH 2 without the addition of salt results in higher masses of attached polyrutin that release slower and over longer time periods. Since wound dressing materials for chronic leg ulcers often require a lower frequency of dressing change, the latter could provide an efficient therapeutic approach to their treatment.
Ključne besede: Chronic wounds, Wound dressings, Cellulose, Polymerization of flavonoids, Rutin, Polyrutin
Objavljeno: 11.06.2018; Ogledov: 145; Prenosov: 20
Celotno besedilo (7,34 MB)