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Tyrosinase catalysed coupling of functional molecules onto protein fibres
Suzana Jus, Vanja Kokol, Georg M. Gübitz, 2008, izvirni znanstveni članek

Opis: Grafting, using oxidative enzymes shows a high potential for wool fibres funktionalisation. In this work we attempt to graft on wool fibres with phenolic antioxidants order to introduce and improve the properties of the fibre. The approach of tyrosinase to oxidize tyrosine residues in wool proteins to quinones, which can further react with free sulfhydryl (thiol), amino or phenolic groups of different substrates was exploited to couple different phenolic antioxidants (caffeic acid and chlorogenic acid) onto the wool fibre proteins. Tyrosinase catalysed reactions were followed by different analytical methods like oxygen consumption, FT-NIR Raman and UV/VIS spectroscopy. It was proved that phenolic compounds used are strongly cross-linked on the wool fibre resulting to an improved antioxidant activity.
Ključne besede: textile fibres, wool fibers, tyrosinase, caffeic acid, chlorogenic acid, grafting, chemical modification of fibres
Objavljeno: 31.05.2012; Ogledov: 575; Prenosov: 6
URL Polno besedilo (0,00 KB)

Enzyme mediated coupling of protein-based biomaterials onto wool fibres
Suzana Jus, Georg M. Gübitz, Vanja Kokol, 2008, objavljeni povzetek znanstvenega prispevka na konferenci

Ključne besede: wool protein fibres, tyrosinase, grafting
Objavljeno: 31.05.2012; Ogledov: 587; Prenosov: 8
URL Polno besedilo (0,00 KB)

The impact of corona modified fibres' chemical changes on wool dyeing
Darinka Fakin, Alenka Ojstršek, Sonja Čelan Benkovič, 2009, izvirni znanstveni članek

Opis: The main contribution of the present work was to study the impact of Corona-treated wool fabricsć induced surface properties on dye-bath exhaustion, in order to optimize different dyeing systems. Firstly, the differing chemical aspects of a woven wool fabricćs surface were determined using two dissimilar analytical skills (XPS and polyelectrolyte titration). With the intention of establish the ability of low-temperature plasma treatment to change wool fibre morphology which could have an impact on sorption properties, fabrics were dyed with blue acid and blue metal-complex dyes, and dyeing behaviour were studied by means of on-line VIS spectrophotometry. Finally, dyed samples were colourimetricaly evaluated and colour differences calculated. The results provided evidence that the overall carbon C 1s content was decreased while oxygen and nitrogen atoms were increased when using ionized air for fabric modification. It has also been noted that the amount of positive-charged functional groups in various pH ranges are higher for Corona-treated wool fabric in comparison with the untreated that improves hydrophylity and dyeing properties.
Ključne besede: Corona treatment, wool, metal-complex dye, acid dye, sorption, colourimetry
Objavljeno: 01.06.2012; Ogledov: 808; Prenosov: 5
URL Polno besedilo (0,00 KB)

Tyrosinase-catalysed coating of wool fibres with different protein-based biomaterials
Suzana Jus, Vanja Kokol, Georg M. Gübitz, 2009, izvirni znanstveni članek

Opis: The potential of tyrosinases to activate tyrosine residues of wool protein fibres for cross-linking with different materials like collagen, elastin and gelatine was assessed. Natural fibres like wool offer an excellent environment for the growth of micro-organisms when the conditions like moisture, oxygen and temperature are appropriate. Coating with collagen, a very useful biomaterial with bactericidal and fungicidal properties, could be used to improve the properties of wool-based materials, especially when applied in hygienically sensitive applications like in hospitals. Tyrosinases were shown to catalyse the oxidation of tyrosine residues in wool and wool hydrolysates as model substrates, as determined by UV-Vis spectroscopy. Structural differences of the surface were evident from the increase of the intensity in the NH bending and stretching regions in the spectra of NIR FT Raman analysis of the enzyme treated and grafted wool fibres. The durability of the coating was also shown by using FITC-labelled collagen that was bound to the wool fibres, even after severe washing. Additionally, antimicrobial properties were successfully imparted due to the collagen grafted on the wool fibres. The functional and mechanical properties of the treated wool fibres showed no significant changes.
Ključne besede: textile fibres, wool, protein substrates, tyrosinase, enzymatic coupling, antimicrobial properties, coating
Objavljeno: 01.06.2012; Ogledov: 641; Prenosov: 3
URL Polno besedilo (0,00 KB)

A novel metalloprotease from Bacillus cereus for protein fibre processing
Fernanda de Sousa, Suzana Jus, Anita Erbel, Vanja Kokol, Artur Cavaco-Paulo, Georg M. Gübitz, 2007, izvirni znanstveni članek

Opis: A novel protease produced by Bacillus cereus grown on wool as carbon and nitrogen source was purified. B. cereus protease is a neutral metalloprotease with a molecular mass of 45.6 kDa. The optimum activity was at 45 °C and pH 7.0. The substrate specificity was assessed using oxidized insulin B-chain and synthetic peptide substrates. The cleavage of the insulin B-chain was determined to be Asn3, Leu6, His10-Leu11, Ala14, Glu21, after 12 h incubation. Among the peptide substrates, the enzyme did not exhibit activity towards ester substrates; with p-nitroanilide, the kinetic data indicate that aliphatic and aromatic amino acids were the preferred residues at the P1 position. For furylacryloyl peptides substrates, which are typical substrates for thermolysin, the enzyme exhibited high hydrolytic activity with a Km values of 0.858 and 2.363 mM for N-(3-[2-Furyl]acryloyl)-Ala-Phe amide and N-(3-[2-Furyl]acryloyl)-Gly-Leu amide, respectively. The purified protease hydrolysed proteins substrates such as azocasein, azocoll, keratin azure and wool.
Ključne besede: textile finishing, enzymatic modification, wool fibre, enzymes, Bacilus cereus, specificity, kinetics, metalloprotease
Objavljeno: 01.06.2012; Ogledov: 642; Prenosov: 2
URL Polno besedilo (0,00 KB)

The influence of enzymatic treatment on wool fibre properties using PEG-modified proteases
Suzana Jus, Marc Schroeder, Georg M. Gübitz, Elisabeth Heine, Vanja Kokol, 2007, izvirni znanstveni članek

Opis: The main contribution of the presented work was to introduce the use of proteases modified with the soluble polymer polyethylene glycol (PEG) in the bio-finishing process of wool fibres, to target enzyme action to the outerparts of wool fibres, i.e. to avoid the diffusion and consequent destroying of the inner parts of the wool fibre structure, in the case of native proteases using. Different proteolytic enzymes from Bacillus lentus and Bacillus subtilis in native and PEG-modified forms were investigated and their influence on the modification of wool fibres morphology surface, chemical structure, as well as the hydrolysis of wool proteins, the physico-mechanical properties, and the sorption properties of 1:2 metal complex dye during dyeing were studied. SEM images of wool fibres confirmed smoother and cleaner fibre surfaces without fibre damages using PEG-modified proteases. Modified enzyme products have a benefit effect on the wool fibres felting behaviours (14%) in the case when PEG-modified B. lentus is used, without markedly fibre damage expressed by tensile strength and weight loss ofthe fibre. Meanwhile the dye exhaustion showed slower but comparable level of dye uptake at the end of the dyeing.
Ključne besede: volnena vlakna, proteolitski encimi, encimske modifikacije, sorpcija barve, morfologija vlaken, wool fibres, proteolytic enzymes, enzyme modification, felting, dye sorption, protein hydrolysis, XPS-analysis, fibre morphology
Objavljeno: 01.06.2012; Ogledov: 1273; Prenosov: 2
URL Polno besedilo (0,00 KB)

Effect of peptides' binding on the antimicrobial activity and biocompatibility of ‎protein-based substrates ‎
Maja Kaisersberger Vincek, 2017, doktorska disertacija

Opis: This work reveals the effect of coupling approach (chemical by using carbodiimide chemistry ‎and grafting-to vs. grafting-from synthesis routes, and enzymatic by using transglutaminase) ‎of a hydrophilic ε-poly-L-lysine (εPL) and an amphiphilic oligo-acyl-lysyl (OAK) derivative (K-7α12-OH) to wool fibers and gelatine (GEL) macromolecules, respectively, and substrates ‎antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria ‎after 1–24 h of exposure, as well as their cytotoxicity. Different spectroscopic (ultraviolet-‎visible, infrared, fluorescence and electron paramagnetic resonance) and separation ‎techniques (size-exclusion chromatography and capillary zone electrophoresis) as well as ‎zeta potential and potentiometric titration analysis, were performed to confirm the covalent ‎coupling of εPL/OAK, and to determine the amount and orientation of its immobilisation.‎ The highest and kinetically the fastest level of bacterial reduction was achieved with ‎wool/GEL functionalised with εPL/OAK by chemical grafting-to approach. This effect ‎correlated with both the highest grafting yield and conformationally the highly-flexible ‎(brush-like) orientation linkage of εPL/OAK, implicating on the highest amount of accessible ‎amino groups interacting with bacterial membrane. However, OAK`s amphipathic structure, ‎the cationic charge and the hydrophobic moieties, resulted to relatively high reduction of S. ‎aureus for grafting-from and the enzymatic coupling approaches using OAK-functionalised ‎GEL. ‎ The εPL/OAK-functionalised GEL did not induce toxicity in human osteoblast cells, even at ‎‎~25-fold higher concentration than bacterial minimum inhibitory (MIC) concentration of ‎εPL/OAK, supporting their potential usage in biomedical applications.‎ It was also shown that non-ionic surfactant adsorbs strongly onto the wool surface during ‎the process of washing, thereby blocking the functional sites of immobilized εPL and ‎decreases its antibacterial efficiency. ‎ ‎
Ključne besede: wool, gelatine, antimicrobial peptides, ε-poly-L-lysine, oligo-acyl-lysyl, grafting chemistry, ‎grafting approach, peptide orientation, antibacterial activity, cytotoxicity‎
Objavljeno: 17.08.2017; Ogledov: 63; Prenosov: 4
.pdf Polno besedilo (3,98 MB)

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