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1 to 50 of 135 results
  • Sonochemical coating of textiles with hybrid ZnO/chitosan antimicrobial nanoparticles

     Petkova Petkova, Petya Stoyanova; Francesko, Antonio; Macedo Fernandes, Margarida Maria; Mendoza Gomez, Ernesto; Perelshtein, Ilana; Aharon, Gedanken; Tzanov, Tzanko
    ACS applied materials and interfaces
    Date of publication: 2014-01-09
    Journal article

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    Textiles are good substrates for growth of microorganisms especially under moisture and temperature conditions found in hospitals. Microbial shedding from the body occurs continuously at contact of the patient with textile materials used in medical practice, contributing to the occurrence of hospital acquired infections. Thus, the use of efficient antimicrobial textiles is necessary to prevent the transfer of pathogens and the infection incidence. In this work, hybrid antimicrobial coatings were generated on cotton fabrics by means of a one-step simultaneous sonochemical deposition of ZnO nanoparticles (NPs) and chitosan. The process was further optimized in terms of reagents concentration and processing time in order to improve the antibacterial properties of the fabric and ensure their biocompatibility. The highest antibacterial activity of the fabrics against two medically relevant bacterial species was achieved in a 30 min sonochemical coating process using 2 mM ZnO NPs suspension. When chitosan was simultaneously deposited with the same amount of ZnO, the obtained hybrid NPs coating displayed higher by 48 and 17 % antibacterial activity against Staphylococcus aureus and Escherichia coli, respectively. The presence of biopolymer also improved the durability of the antimicrobial effect of the coatings by 21 % for Staphylococcus aureus and 40 % for Escherichia coli, evaluated after applying multiple washing cycles at hospital laundering regimes. Finally, 87 % biocompatibility improvement supported by fibroblast viability was observed for the hybrid ZnO/chitosan coating compared to the steady decrease of cells viability over one week in contact with the fabrics coated with ZnO alone.

  • An enzymatic approach to develop a lignin-based adhesive for wool floor coverings

     Aracri, Elisabetta; Diaz Blanco, Carlos; Tzanov, Tzanko
    Green Chemistry
    Date of publication: 2014-02-04
    Journal article

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    This work describes a novel enzymatic approach to develop a lignin-based adhesive aimed at replacing synthetic latex in wool floor coverings. The adhesive production consisted of a lignin pre-activation step to oxidise it by a laccase-enhancer system followed by a phenolation step where natural phenolic compounds were copolymerised with lignin in order to increase its content of quinone structures reactive towards wool. The electrochemical behaviour of the adhesive precursors and the influence of process conditions on the adhesive characteristics suggested that the phenolic compounds were able to autopolymerise and copolymerise between themselves and with lignin during the enzymatic reaction. Consequently, the flexibility and bonding strength of the adhesive increased. The latter showed strength performance similar to that of the traditional latex-based adhesive. Satisfactory level of flexibility was obtained using polyethylene glycol as an external plasticizer of lignin.

  • FUNCTIONAL MATERIALS FOR LAST DIAGNOSIS OF WOUND INFECTION

     Tzanov, Tzanko
    Participation in a competitive project

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  • Myeloperoxidase: A paradoxical enzyme - from host defense to disease

     Díaz-González, Margarita; Francesko, Antonio; Macedo Fernandes, Margarida Maria; Tzanov, Tzanko
    Date of publication: 2013-01-30
    Book chapter

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  • Gallic acid implications in health: multi-therapeutic and protective agent

     Francesko, Antonio; Macedo Fernandes, Margarida Maria; Tzanov, Tzanko
    Date of publication: 2013-07-15
    Book chapter

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  • A new approach to produce plant antioxidant-loaded chitosan for modulating proteolytic environment and bacterial growth

     Rocasalbas Lozano, Guillermo; Touriño Eirin, Sonia; Torres, Josep Lluis; Tzanov, Tzanko
    Journal of materials chemistry B
    Date of publication: 2013-01-14
    Journal article

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    This work reports a straightforward approach for incorporation of plant-derived flavonoid-based antioxidants into an intrinsically antimicrobial chitosan platform in order to generate chitosan-based materials suitable for biomedical applications. The novelty of this approach consists in the use of thioacidolysis ¿ a common analytical method for the characterization of proanthocyanidins ¿ to covalently functionalize natural macromolecules such as chitosan with bioactive phenolic moieties. It is known that proanthocyanidins undergo depolymerization in acid medium, where in the presence of nucleophiles they form stable flavan-3-ol derivatives. Based on this reaction, flavan-3-ol moieties from the polyphenol extract of Hamamelis virginiana are incorporated covalently into a previously thiolated chitosan matrix. The phenolics-functionalized chitosan possesses improved antioxidant and antimicrobial properties, and inhibitory efficiency over deleterious wound enzymes in vitro.

    This work reports a straightforward approach for incorporation of plant-derived flavonoid-based antioxidants into an intrinsically antimicrobial chitosan platform in order to generate chitosan-based materials suitable for biomedical applications. The novelty of this approach consists in the use of thioacidolysis – a common analytical method for the characterization of proanthocyanidins – to covalently functionalize natural macromolecules such as chitosan with bioactive phenolic moieties. It is known that proanthocyanidins undergo depolymerization in acid medium, where in the presence of nucleophiles they form stable flavan-3-ol derivatives. Based on this reaction, flavan-3-ol moieties from the polyphenol extract of Hamamelis virginiana are incorporated covalently into a previously thiolated chitosan matrix. The phenolics-functionalized chitosan possesses improved antioxidant and antimicrobial properties, and inhibitory efficiency over deleterious wound enzymes in vitro.

  • Tannic Acid NPs - Synthesis and immobilization on to a solid surface in a one ¿ step process and their antibacterial and anti-inflammatory properties

     Perelshtein, Ilana; Ruderman, Elena; Francesko, Antonio; Fernandes, Margarida M.; Tzanov, Tzanko; Macedo Fernandes, Margarida Maria; Gedanken, Aharon
    Ultrasonics sonochemistry
    Date of publication: 2013-12-14
    Journal article

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    Tannic acid nanoparticles were synthesized from an aqueous solution without the use of stabilizers via a sonochemical process. In order to avoid the dissolution of the formed nanoparticles, the sonochemical reaction was performed in the presence of a cotton fabric: following their formation, the tannic acid nanoparticles were embedded into the cotton substrate in a one-step process. The bioactive properties of the tannic acid coated surface were examined towards the inhibition of myeloperoxidase and collagenase, two major enzymes related with inflammatory processes. In addition, the antibacterial activity of the tannic acid nanoparticles coated textiles was evaluated against Staphylococcus aureus and Pseudomonas aeruginosa. © 2013 Elsevier B.V. All rights reserved.

  • Use of cyclic voltammetry as an effective tool for selecting efficient enhancers for oxidative bioprocesses: Importance of pH

     Aracri, Elisabetta; Tzanov, Tzanko; Vidal Llucia, Teresa
    Industrial & engineering chemistry research
    Date of publication: 2013-01-04
    Journal article

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    Seven natural phenols and two synthetic compounds were evaluated by means of cyclic voltammetry as enhancers for the oxidation of the lignin model compound veratryl alcohol (VAl) and a sulfonated lignin (SL). Their electrochemical behaviors and catalytic efficiencies (CEs) against both substrates were assessed as a function of pH. A general increase in CE of the phenols was for the first time observed in the oxidation of VAl at pH 7 and 8. Methyl syringate (MS), syringic acid (SRC), and syringaldehyde (SRD) exhibited the highest CEs against VAl among the studied phenolic compounds despite the reduced stabilities of their phenoxy radicals. This was a result of favorable stability−reactivity balances, which were apparently influenced by both the chemical structures of the enhancers and the experimental conditions. Violuric acid (VAc) proved the most efficient compound in oxidizing lignin, followed by SRD and MS, which showed regeneration in the interval of pHs studied

  • Chitosan and chitosan ZnO-based complex nanoparticles: formation, characterization, and antibacterial activity

     Perelshtein, Ilana; Ruderman, Yelena; Perkas, Nina; Tzanov, Tzanko; Beddow, Jamie; Joyce, Eadaoin; Mason, Timothy J.; Blanes, María; Mollá, Korina; Patlolla, Anitha; Frenkel, Anatoly I.; Gedanken, Aharon
    Journal of materials chemistry B
    Date of publication: 2013-02-04
    Journal article

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  • Effect of thiol-functionalisation on chitosan antibacterial activity: interaction with a bacterial membrane model

     Macedo Fernandes, Margarida Maria; Francesko, Antonio; Torrent Burgues, Juan; Tzanov, Tzanko
    Reactive and functional polymers
    Date of publication: 2013-01-12
    Journal article

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    The antibacterial activity of chitosan modified with the thiol-containing 2-iminothiolane HCl (TC-IMI) and N-acetyl- L -cysteine (TC-NAC) was studied by Langmuir film balance technique using a dipalmitoylphos- phatidylglycerol (DPPG) monolayer bacterial membrane model. The interactions of the biopolymer with the membrane model were assessed by monitoring the differences in the shape of the compression iso- therms recorded in the absence and presence of chitosan and thiolated conjugates in the subphase. A low molecularweightchitosan(15 kDa)shiftedthecompressionisothermsofDPPGmonolayerstowardslarger areas ( A 0,CS = 145 Å 2 ), confirming its membrane disturbance capacity. Further thiolation induced higher yield of expansion, more pronounced in the case of TC-IMI. The expansion of the monolayer increased sig- nificantly( A 0,TC-NAC = 150 Å 2 vs A 0,TC-IMI = 175 Å 2 )andtheelasticityatasurfacepressureof30 mN/m,typical for bio-membranes decreased to a greater extent C 1 s ; 30 TC NAC = 120 mN/m vs C 1 s ; 30 TC IMI = 87 mN/m) in presence of TC-IMI. Antibacterial tests against a Gram-negative Escherichia coli and a Gram-positive Staph- ylococcusaureus wereingoodagreementwiththesefindings,suggestingthatchitosanthiolatedwith2-imi- nothiolane HCl acts as a bactericide disrupting the integrity of the bacterial cell membrane

  • NOVEL COATINGS TO PREVENT BIOFILM FORMATION ON URINARY

     Tzanov, Tzanko
    Participation in a competitive project

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  • APOSITOS ACTIVOS PARA HERIDAS CRONICAS BASADOS EN BIOPOLIMEROS

     Tzanov, Tzanko
    Participation in a competitive project

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  • Enzymatic pre-treatment as a means of enhancing the antibacterial activity and stability of ZnO nanoparticles sonochemically coated on cotton fabrics

     Perelshtein, Ilana; Ruderman, Yelena; Perkas, Nina; Traeger, Kamelia; Tzanov, Tzanko; Beddow, Jamie; Joyce, Eadaoin; Mason, Timothy J.; Blanes, María; Mollá, Korina; Gedanken, Aharon
    Journal of materials chemistry B
    Date of publication: 2012
    Journal article

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  • Light harvesting amphiphiles boost the performance of lipase-based washing formulations

     Díaz Blanco, Carlos; Trifonov, Antoli; Georgiev, George; Tzanov, Tzanko
    Enzyme and microbial technology
    Date of publication: 2012-08-10
    Journal article

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  • Enzymatic functionalization of protein fibers to confer cationic dye absorption

     Gaffar Hossain, Kh. M.; Grabherl, Günter; Tzanov, Tzanko
    Melliand international
    Date of publication: 2012-03-31
    Journal article

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  • Hematoporphyrin-based amphiphiles boost the washing performance of protease-containing formulations in a biomimetic approach

     Díaz Blanco, Carlos; Trifonov, Antoli; Georgiev, G.; Tzanov, Tzanko
    Journal of molecular catalysis B. Enzymatic
    Date of publication: 2012-06
    Journal article

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  • Enzymatic pre-treament as a means of enhancing the antibacterial activity and stability of ZnO nanoparticles sonochemically coated on cotton fabrics

     Perelshtein, Ilana; Ruderman, Yelena; Perkas, Nina; Traeger, Kamelia; Tzanov, Tzanko; Beddow, Jamie; Joyce, Eadaoin; Mason, Timothy J.; Blanes, María; Mollá, Korina; Gedanken, Aharon
    Journal of materials chemistry B
    Date of publication: 2012-03-15
    Journal article

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    Zinc oxide nanoparticles (ZnO NP’s) are known for their excellent antibacterial properties. This paper describes a method for enhancing the stability and the antibacterial activity of ZnO NPs synthesized and embedded sonochemically on cotton fabrics, by pre-treating the fabric surface with cellulase enzyme. The enzymatic pre-treatment resulted in the deposition of smaller sized NPs with improved adhesion. The reduction in particle size brought about better antibacterial performance against several types of bacteria. The sonochemically produced ZnO coating withstood 10 laundry cycles at 92º C retaining its antibacterial activity.

  • Laccase-assisted formation of bioactive chitosan/gelatin hydrogel stabilized with plant polyphenols

     Rocasalbas Lozano, Guillermo; Francesko, Antonio; Touriño Eirin, Sonia; Fernández Francos, Xavier; Guebitz, Georg M.; Tzanov, Tzanko
    Carbohydrate polymers
    Date of publication: 2012-11-02
    Journal article

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    Laccase-assisted simultaneous cross-linking and functionalization of chitosan/gelatin blends with phenolic compounds from Hamamelis virginiana was investigated for the development of bioactive hydrogel dressings. The potential of these hydrogels for chronic wound treatment was evaluated in vitro, assessing their antibacterial and inhibitory effect on myeloperoxidase and collagenase. Rheological studies revealed that the mechanical properties of the hydrogels were a function of the enzymatic reaction time. Stable hydrogels and resistant to lysozyme degradation were achieved after 2 h laccase reaction. The inhibitory capacity of the hydrogel for myeloperoxidase and collagenase was 32% and 79% respectively after 24 h incubation. Collagenase activity was additionally suppressed by adsorption (20%) of the enzyme onto the hydrogel. Therefore, the bioactive properties of the hydrogels were due to the effect of both released phenolic compounds and the permanently functionalized platform itself. The hydrogels showed antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus.

    Laccase-assisted simultaneous cross-linking and functionalization of chitosan/gelatin blends with phenolic compounds from Hamamelis virginiana was investigated for the development of bioactive hydrogel dressings. The potential of these hydrogels for chronic wound treatment was evaluated in vitro, assessing their antibacterial and inhibitory effect on myeloperoxidase and collagenase. Rheological studies revealed that the mechanical properties of the hydrogels were a function of the enzymatic reaction time. Stable hydrogels and resistant to lysozyme degradation were achieved after 2 h laccase reaction. The inhibitory capacity of the hydrogel for myeloperoxidase and collagenase was 32% and 79% respectively after 24 h incubation. Collagenase activity was additionally suppressed by adsorption (20%) of the enzyme onto the hydrogel. Therefore, the bioactive properties of the hydrogels were due to the effect of both released phenolic compounds and the permanently functionalized platform itself. The hydrogels showed antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus.

  • Functional biopolymer-based matrices for modulation of chronic wound enzyme activities

     Francesko, Antonio; Soares da Costa, Diana; Reis, Rui Luís; Pashkuleva, Iva; Tzanov, Tzanko
    Acta biomaterialia
    Date of publication: 2012-10-13
    Journal article

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    Collagen, collagen/hyaluronic acid (HA) and collagen/HA/chitosan (CS) sponges loaded with epigallocatechin gallate (EGCG), catechin (CAT) and gallic acid (GA) were developed and evaluated as active chronic wound dressings. Their physico-mechanical properties, biostability, biocompatibility and ability to inhibit in vitro myeloperoxidase (MPO) and collagenase—major enzymes related with the persistent inflammation in chronic wounds—were investigated as a function of the biopolymer composition and the polyphenolic compound used. The results demonstrated that the molecular weight of HA influences significantly the bulk properties of the obtained materials: higher elastic modulus, swelling ability and biostability against collagenase were measured when HA with higher molecular weights (830 and 2000 kDa) were added to the collagen matrices. The addition of CS and the polyphenols increased further the biostability of the sponges. Preliminary in vitro tests with fibroblasts revealed that the cells were able to adhere to all sponges. Cell viability was not affected significantly by the addition of the polyphenols; however, the presence of CS or high molecular weight HA in the sponge composition was associated with lower cellular viability. Finally, all specimens containing polyphenols efficiently inhibited the MPO activity. The highest inhibition capacity was observed for EGCG (IC50 = 15 ± 1 μM) and it was coupled to the highest extent of binding to the biopolymers (>80%) and optimal release profile from the sponges that allowed for prolonged (up to 3–5 days) effects.

  • Development of multifunctional biopolymeric materials for teatment of decubitus ulcers  Open access

     Rocasalbas Lozano, Guillermo
    Defense's date: 2012-11-30
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

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    Chronic wounds including pressure, venous, arterial and diabetic neuropathic ulcers, represent a significant burden to the healthcare system. These different chronic wound types do not share origin or cause, however they have common features as bacterial infection and continuing influx of polymorphonuclear neutrophils that release high concentrations of matrix metalloproteases (MMPs), myeloperoxidase (MPO) and reactive oxidative species causing excessive degradation of the extracellular matrix (ECM) and the growth factors. Because of the multifactorial nature of virtually all chronic wounds, the therapeutic wound healing approach should emphasize the necessity to investigate wound dressings that possess the ability to directly and indirectly modulate the biochemical environment based on the pathology of chronic to encourage the healing process. The overall aim of the present work was to develop biopolymer wound dressings capable to improve the management of chronic wounds. The specific research objective was defined in three main targets: i) to balance the proteolytic activity of MMPs, ii) to balance the MPO activity and the oxidative environment, and iii) antimicrobial protection. The first part of the thesis aimed to provide suitable materials to perform bioactive biopolymer-based wound dressings. The first step was to provide a versatile functionalization of chitosan platform to improve the sequestering ability over metal dependent enzymes (MMPs) in chronic wounds. In order to impart to chitosan the ability to inhibit MMP, chitosan was functionalized with deferent thiol moieties, which can chelate the zinc cation in the active site of the enzyme, modifying MMP activity. In addition the combination of -NH2 and -SH chemistry allowed grafting of other active agents on the chitosan platform. The second step was the identification and evaluation of natural active agents as chronic wound healing promoters. Polyphenols from bark, twigs and leaf extracts from the medicinal plant Hamamelis virginiana (Witch hazel) were studied for this porpoise and it was found to have both a strong antioxidant activity and an inhibitory effect on MPO and collagenase. The second part of the thesis was focused in the performance and evaluation of new materials for wound healing applications. To this aim, chitosan and/or thiolated chitosan were modified with H. virginiana extracts following different approaches. The first approach was focused to develop a new method for covalent functionalization of thiolated chitosan with polyphenols from H. virginiana extracts. The novelty of this approach consists in the use of thiolysis - a common analytical method for proanthocyanidins characterization - to covalently functionalize natural macromolecules such as chitosan with bioactive phenolic moieties. The phenolics-functionalized chitosan showed improved therapeutic properties in vitro. The second approach focused on the use of laccase-assisted cross-linking between phenolic moieties of H. virginiana with chitosan and gelatin as a functionalization method to obtain stable and bioactive hydrogel wound dressings. H. virginiana extract was oxidized by laccase in a one-step process under mild reaction conditions to covalently crosslink chitosan and gelatin. The physical and mechanical properties of these hydrogels were investigated using different analytical techniques and their potential for chronic wound treatment was evaluated in vitro in terms of antibacterial and inhibitory effect on MPO and collagenase. The results indicated that the polyphenols exerted a dual role in the hydrogel: i) "passive" being a structural element, and ii) "active" modifying the chronic wound environment by attenuating the deleterious MMPs, MPO and ROS activities, and reducing the bacterial load.

  • Multifuncional biopolymer-bases materials for modulatig the activites of chromic wound enzymes  Open access

     Francesko, Antonio
    Defense's date: 2012-11-29
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

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    This thesis focuses on the development of active multifunctional dressing materials and nanoparticle formulations with suitable exploitation characteristics for chronic wounds treatment. Chronic wounds a growing clinical challenge in the aging and/or reduced mobility population include pressure, venous, arterial and diabetic neuropathic ulcers. Due to the nonhealing character of these ulcers their management requires an intensive medical intervention at huge healthcare costs. The prolonged inflammation and elevated concentrations of oxidative and proteolytic enzymes in all chronic wounds, imposes the need for novel functional dressing materials to actively modulate the wound environment at molecular level and stimulate the healing process. Based on an extensive analysis of the current state-of-the-art in chronic wound healing, the proper dressings should combine both antimicrobial and enzyme inhibitory functions coupled to optimal hydrophilicity. Such integrated approach would allow for the suppression of the persistent inflammation and stimulation of the synthesis of the dermal tissue components. Biopolymers with intrinsic antimicrobial and wound repair properties appear as appropriate matrix materials to be further upgraded with bioactive molecules (therapeutics) that couple high reactivity with the ability to address specific targets in the biochemical environment of chronic wounds. Therapeutic devices can be designed in different forms depending on the particular clinical application, i.e. wound type and its characteristics. During the thesis realisation biopolymer-based platforms were generated in various designs and functionalised with active agents for controlled inhibition of major chronic wound enzymes. The capacity of all developed materials to inhibit proteolytic (e.g. collagenase) and oxidative (e.g. myeloperoxidase) enzymes involved in chronic inflammation was evaluated in vitro. In the first approach sponge-like biopolymer matrices were produced via freeze-drying technique and controlled chemical cross-linking. These matrices were further impregnated with natural polyphenolic compounds. Modulation of the deleterious wound enzyme activities was achieved upon release of active agent from the platform. The exploitation characteristics of the sponges, i.e. mechanical properties, biostability, biocompatibility, extent and duration of wound enzymes inhibition, were tuned by: the biopolymer composition, concentration of the cross-linking agent, and the proper selection of the bioactive phenolic compounds. The second approach aimed at the permanent functionalisation of the biopolymeric platforms with thiol-bearing compounds. In this case the active agent is expected to act from the platform, without being released into the wound. The obtained thiolated biopolymers were further processed into functional nanomaterials of different design: *Nanoscale films/coatings were built using a layer-by-layer approach for alternate deposition of oppositely charged polyelectrolytes. Naturally occurring glycosaminoglycans were used as counterions to cationic thiolated conjugates. *Nanoparticle formulations were obtained from thiolated conjugates in a one-step sonochemical process. In both cases the biopolymer thiolation degree was identified as a key factor for the successful fabrication of the multilayered coatings and nanoparticles, as well as to achieve control of the thickness/size of the functional nanomaterials. In addition, tuneable inhibition/adsorption of the deleterious enzymes coupled to fibroblast attachment/proliferation was observed by ruling the biopolymer modification degree.

  • ADDED VALUE FROM HIGH PROTEIN AND HIGH OIL INDUSTRIAL CO-STREAMS

     Tzanov, Tzanko
    Participation in a competitive project

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  • A bio-based floor covering with ERUTAN inside

     Tzanov, Tzanko
    Participation in a competitive project

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  • GAGs-thiolated chitosan assemblies for chronic wounds treatment: control of enzyme activity and cell attachment

     Francesko, Antonio; Soares da Costa, Diana; Lisboa, Patricia; Reis, Rui Luís; Tzanov, Tzanko; Iva Hristova, Pashkuleva
    Journal of materials chemistry B
    Date of publication: 2012-04-20
    Journal article

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    Multilayered polyelectrolyte coatings comprising thiolated chitosan (TC) and glycosaminoglycans (GAGs), chondroitin sulphate and hyaluronic acid, were built using a layer-by-layer approach. The surface activity of these coatings for binding and inhibition of enzymes related to chronic inflammation, such as collagenase and myeloperoxidase, was assessed. The build-up of five bi-layers of TC/GAGs onto gold surfaces was monitored in situ by QCM-D. All experimental groups showed exponential growth of the coatings controlled by the degree of chitosan thiolation and the molecular weight of the GAGs. The degree of chitosan modification was also the key parameter influencing the enzyme activity: increasing the thiols content led to more efficient myeloperoxidase inhibition and was inversely proportional to the adsorption of collagenase. Enhanced fibroblast attachment and proliferation were observed when the multilayered polyelectrolyte constructs terminated with GAGs. The possibility to control either the activity of major wound enzymes by the thiolation degree of the coating or the cell adhesion and proliferation by proper selection of the ultimate layer makes these materials potentially useful in chronic wounds treatment and dermal tissue regeneration.

  • Inhibition of deleterious chronic wound enzymes with plant polyphenols

     Díaz-González, María; Rocasalbas Lozano, Guillem; Francesko, Antonio; Touriño Eirin, Sonia; Torres, Josep Lluis; Tzanov, Tzanko
    Biocatalysis and biotransformation
    Date of publication: 2012-01-18
    Journal article

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    The chronic wound environment is characterized by high concentrations of reactive oxygen species (ROS) and elevated levels of myeloperoxidase (MPO) and collagenases, together impairing the healing process. Therefore, the management of chronic wounds at a molecular level requires the synergistic use of antioxidants, MPO and collagenase inhibitors to simultaneously target multiple factors from wound pathogenesis. In this study, a polyphenolic extract from Hamamelis virginiana plant, rich in condensed and hydrolysable oligomeric tannins, was evaluated as an inhibitor of MPO and collagenase.In addition to efficient scavengers of radical and non-radical reactive species, H. virginiana polyphenols were found to act as substrates in the MPO peroxidase cycle, preventing the accumulation of ROS in the chronic wound site. Furthermore, it was also found that the plant exerts an irreversible inhibitory effect on collagenase activity (IC50 = 75 ± 10 μg/mL)

  • Cross-linked collagen sponges loaded with plant polyphenols with inhibitory activity towards chronic wound enzymes

     Francesko, Antonio; Rocasalbas Lozano, Guillem; Touriño Eirin, Sonia; Mattu, Clara; Gentile, Piergiorgio; Chiono, Valeria; Ciardelli, Gianluca; Tzanov, Tzanko
    Biotechnology journal
    Date of publication: 2011-10
    Journal article

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  • Chitosan microspheres

     Touriño Eirin, Sonia; Tzanov, Tzanko
    Date of publication: 2011-12-01
    Book chapter

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  • Biotechnical and biomimetic approaches for coating of textile surfaces and enhancement of cleaning formulations

     Díaz Blanco, Carlos
    Defense's date: 2011-12-19
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

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  • Aplicaciones Biomedicas Avanzadas

     Tzanov, Tzanko
    Participation in a competitive project

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  • Preparación de 2 proyectos del VII Programa Marco de I+D de la Unión Europea

     Tzanov, Tzanko
    Participation in a competitive project

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  • Protein disulphide isomerase-assisted functionalization of keratin-based matrices

     Fernandes, M.M.; Gomez, Andreia C.; Vasconcelos, Andreia; Munteanu, Florentina Daniela; Tzanov, Tzanko; Gonçalves, M.S.T; End, Nicole; Schoening, K. U.; Guebitz, Georg; Cavaco-Paulo, Artur
    Applied microbiology and biotechnology
    Date of publication: 2011-03-19
    Journal article

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  • Sensor materials for the detection of human neutrophil elastase and cathepsin G activity in wound fluid

     Hasmann, Andrea; Gewessler, Ulrike; Hulla, Elisabet; Schneider, Konstantin P.; Binder, Barbara; Francesko, Antonio; Tzanov, Tzanko; Schintler, Michael; Van der Palen, Job; Guebitz, George M.; Wehrschuetz-Sigl, Eva
    Experimental dermatology
    Date of publication: 2011-04-13
    Journal article

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    Human neutrophil elastase (HNE) and cathepsin G (CatG) are involved in the pathogenesis of a number of inflammatory disorders. These serine proteinases are released by neutrophils and monocytes in case of infection. Wound infection is a severe complication regarding wound healing causing diagnostic and therapeutic problems. In this study we have shown the potential of HNE and CatG to be used as markers for early detection of infection. Significant differences in HNE and CatG levels in infected and non-infected wound fluids were observed. Peptide substrates for these two enzymes were successfully immobilised on different surfaces, including collagen, modified collagen, polyamide polyesters and silica gel. HNE and CatG activities were monitored directly in wound fluid via hydrolysis of the chromogenic substrates. Infected wound fluids led to significant higher substrate hydrolysis compared with non-infected ones. These different approaches could be used for the development of devices which are able to detect elevated enzyme activities before manifestation of infection directly on bandages. This would allow a timely intervention by medical doctors thus preventing severe infections.

  • Phenolic compounds as enhancers in enzymatic and electrochemical oxidation of veratryl alcohol and lignins

     Diaz González, Maria; Vidal Llucia, Teresa; Tzanov, Tzanko
    Applied microbiology and biotechnology
    Date of publication: 2011-03
    Journal article

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    Sixteen phenolic compounds, 14 of which naturally occurring, were compared to the synthetic 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and violuric acid (VA) in terms of their ability to act as mediators/enhancers in: (1) laccase oxidation of veratryl alcohol as a lignin model compound, and (2) electrochemical oxidation of kraft and flax lignins. HPLC analysis revealed that the syringyl-type phenols methyl syringate and acetosyringone were the most efficient natural enhancers in the laccase oxidation of veratryl alcohol. Both compounds, though far from the performance of ABTS were able to generate veratraldehyde in amount similar to that obtained with VA. By contrast, the best performing phenolic enhancers for the electrochemical oxidation of lignins were sinapinaldehyde, vanillin, acetovanillone, and syringic acid. Catalytic efficiencies close to those achieved with ABTS and VA were calculated for these phenolic compounds.

  • A single step enzymatic modification of wool textile to improve its various properties

     Gaffar Hossain, Kh. M.; Diaz González, Maria; Riva Juan, Ascension; Tzanov, Tzanko
    AATCC International Conference
    Presentation's date: 2010-05-18
    Presentation of work at congresses

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  • Effects of alkyl chain lengths of gallates upon enzymatic wool functionalisation

     Gaffar Hossain, Kh. M.; Diaz González, Maria; Daga Monmany, Jose Maria; Tzanov, Tzanko
    Journal of molecular catalysis B. Enzymatic
    Date of publication: 2010-08-24
    Journal article

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    The covalent grafting of alkyl gallates on wool through a laccase catalysed reaction in 80/20 (v/v, %)aqueous–ethanol mixture provided in a one-step process a multifunctional textile material with antioxidant, antibacterial and water repellent properties. Gallic acid and its alkyl esters ethyl, propyl, octyl and dodecyl gallate have been enzymatically grafted on wool fibres in order to study the effect of alkyl chain length on wool functional modification. The capacity of laccase to oxidise these phenolic compounds in an aqueous–organic medium has been verified by electrochemical techniques. The increase of CH2, CH3 groups in the FTIR spectra, together with the XPS analysis of the enzymatically modified fabrics confirmed the covalent grafting of ester gallates on wool. The result obtained in this work for antibacterial, water repellent as well as antioxidant properties show that the length of the alkyl chain of gallates molecule play an important role on wool functionalisation.

  • One-step preparation of multifunctional chitosan microspheres by a simple sonochemical method

     Skirtenko, Natalia; Tzanov, Tzanko; Gedanken, Aharon; Rahimipour, Shai
    Chemistry: a european journal
    Date of publication: 2010
    Journal article

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    Chitosan is a biodegradable natural polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density, nontoxicity, and mucoadhesion properties. Processing techniques for the preparation of chitosan microspheres have been extensively developed since the 1980s. The present paper describes for the first time a fast and one-step process for the preparation of stable chitosan microspheres by a simple sonochemical method. The microspheres were characterized by their particle size, surface morphology, stability, and drug-entrapment efficiency The average size of the microspheres was found to be around 1 mm with a narrow size distribution, which enabled them to be used for in vivo applications. The encapsulation of different dyes into these microspheres was readily achieved with more than 75% efficacy by dissolving them into the organic phase before sonication. The chitosan microspheres demonstrated excellent stability toward acidic and basic conditions ranging from pH 4 to 9, thereby indicating their implementation as possible therapeutic and diagnostic agents. The stability of these microspheres appears to be contributed from intermolecular imine cross-linking in addition to other noncovalent interactions. The ability of the surface-exposed amino groups of chitosan microspheres to undergo chemical conjugation with potential drugs and/or targeting vectors was determined by their reaction with fluorescein isothiocyanate (FITC) and fluorescamine followed by confocal microscopy

  • Developments in the processing of chitin, chitosan and bacterial cellulose for textile and other applications

     Francesko, Antonio; Diaz González, Maria; Lozano, G.R.; Tzanov, Tzanko
    Date of publication: 2010-10-01
    Book chapter

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  • Chitin, chitosan and derivatives for wound healing and tissue engineering

     Francesko, Antonio; Tzanov, Tzanko
    Date of publication: 2010-07-31
    Book chapter

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  • Plant polyphenols modified chitosan to inhibit human myeloperoxidase chlorinating activity

     Diaz González, Maria; Rocasalbas Lozano, Guillem; Francesko, Antonio; Tzanov, Tzanko
    New biotechnology
    Date of publication: 2010-09
    Journal article

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  • A method for providing a textile product, the product itself and its use

     Christiaan Mathias, Hubertus Gerard; Tzanov, Tzanko; Blanco Diaz, Carlos
    Date of request: 2010-06-30
    Invention patent

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  • Dyeing properties, synthesis, isolation and characterization of an in situ generated phenolic pigment, covalently bound to cotton

     Díaz Blanco, Carlos; Diaz González, Maria; Daga Monmany, Jose Maria; Tzanov, Tzanko
    Enzyme and microbial technology
    Date of publication: 2009-06
    Journal article

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  • Multifunctional modification of wool using an enzymatic process in aqueous¿organic media

     Hossain, Kmg; Diaz González, Maria; Lozano, Gr; Tzanov, Tzanko
    Journal of biotechnology
    Date of publication: 2009-04
    Journal article

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  • Voltametric monitoring of enzyme-mediated indigo reduction in the presence of various fibre materials

     Bozic, M; Diaz González, Maria; Tzanov, Tzanko; Guebitz, GM; Kokol, V
    Enzyme and microbial technology
    Date of publication: 2009-10
    Journal article

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  • Permanent dyeing of cotton with enzymatically in situ generated phenolic pigment

     Diaz González, Maria; Daga Monmany, Jose Maria; Tzanov, Tzanko
    Enzyme and microbial technology
    Date of publication: 2009-06
    Journal article

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  • Access to the full text
    Enzyme-mediated coupling of a bi-functional phenolic compound onto wool to enhance its physical, mechanical and functional properties  Open access

     Gaffar Hossain, Kh. M.; Diaz González, Maria; Riva Juan, Ascension; Tzanov, Tzanko
    Enzyme and microbial technology
    Date of publication: 2009-12-08
    Journal article

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    Wool fibres have been modified with nordihydroguaiaretic acid (NDGA) to improve their performance at use. This water insoluble bi-functional phenolic compound has been grafted on wool through a laccase enzyme catalyzed reaction in an aqueous-ethanol mixture. The capacity of laccase to oxidise NDGA in this aqueous-organic medium has been studied electrochemicaly. The increase of CH2, CH3 and aromatic groups signal in the DRIFT spectra, together with SEM images of the enzymatically-modified fabrics confirmed the covalent grafting of NDGA on wool. This one step enzymatic process for grafting of NDGA improved the physical and mechanical properties of wool fabrics such as shrink resistance, crease recovery and tensile strength. Furthermore, the NDGA imparted to the textile material strong antioxidant activity and UV-protection.

    Electronic version of an article published as "Enzyme and microbial technology", 08 Desembre 2009, p. 1-5

    Postprint (author’s final draft)

  • Electrochemical Study of Phenolic Compounds as Enhancers in Laccase-Catalyzed Oxidative Reactions

     Diaz González, Maria; Vidal Llucia, Teresa; Tzanov, Tzanko
    Electroanalysis
    Date of publication: 2009-09
    Journal article

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  • PREPARACIÓN DE 2 PROYECTOS DEL VII PROGRAMA MARCO DE I+D DE LA UNION EUROPEA

     Tzanov, Tzanko
    Participation in a competitive project

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