Diaz, C.; Ortner, A.; Dimitrov, R.; Navarro, A.; Mendoza, E.; Tzanov, T. ACS applied materials and interfaces Vol. 6, num. 14, p. 11385-11393 DOI: 10.1021/am501961b Data de publicació: 2014-06-23 Article en revista
Catheter associated urinary tract infections are common during hospitalization due to the formation of bacterial biofilms on the indwelling device. In this study, we report an innovative biotechnology-based approach for the covalent functionalization of silicone catheters with antifouling zwitterionic moieties to prevent biofilm formation. Our approach combines the potential bioactivity of a natural phenolics layer biocatalytically conjugated to sulfobetaine-acrylic residues in an enzymatically initiated surface radical polymerization with laccase. To ensure sufficient coating stability in urine, the silicone catheter is plasma-activated. In contrast to industrial chemical methods, the methacrylate-containing zwitterionic monomers are polymerized at pH 5 and 50 °C using as an initiator the phenoxy radicals solely generated by laccase on the phenolics-coated catheter surface. The coated catheters are characterized by X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared (FTIR) analysis, atomic force microscopy (AFM), and colorimetrically. Contact angle and protein adsorption measurements, coupled with in vitro tests with the Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus in static and dynamic conditions, mimicking the operational conditions to be faced by the catheters, demonstrate reduced biofilm formation by about 80% when compared to that of unmodified urinary catheters. The zwitterionic coating did not affect the viability of the human fibroblasts (BJ-5ta) over seven days, corresponding to the extended useful life of urinary catheters.
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.
The objective is a first industrial application of the eco-innovative solution ERUTAN (nature backwards), with the intention to reach global replication of the environmentally friendly production process for wool floor coverings. ERUTAN is developed at pilot scale by three SME/s in cooperation with European R&D partners and brings a high added value to the global carpet market. The main objectives and steps beyond the state-of-the-art of this project are: i) up-scaling of an innovative, sustainable enzymatic wool scouring method, ii) up-scaling of a novel enzymatic process for bonding between the yarns and supporting material of the carpet. WP2, realisation of an industrial enzymatic wool scouring process, enables sheep farmers worldwide to scour their own raw wool environmentally responsible. The carpet backing approach brings considerable energy saving and low, if any, carbon footprint using naturally based adhesives and enzymes.
ERUTAN is the first real innovation in manufacturing of textile floor covering since 1960. Although the single production steps remain equal, the environmental impact and production method change greatly. The pilot line for wool scouring, located at partner JMS, will be adapted to reach the industrial standard of scouring 10 tons of raw wool within 6 hours. Intensification is further achieved by optimizing enzyme formulation and conditions for application. Regarding the enzymatic bonding process 4 tasks are planned for WP3: Identification of potential providers for adhesives precursors and enzymes, Up-scaling backing line, Up-scaling adhesive paste, Optimization of process parameters and paste application technology. Within LCA work package, input of ERUTAN carpet after its use phase into a second life such as substrates for the agro and food industry, is taken into account. In WP5, business plan related to the exploitation and commercialization of the industrially developed processes and products. Dissemination activities are in WP6.
'Biofilms are bacterial communities encased in a self-produced hydrated polymeric matrix. An important characteristic of microbial biofilms is their innate resistance to the immune system and susceptibility to antibiotics. This resistance has made microbial biofilms a common cause of medical infections, and difficult-to-treat infections caused by colonized foreign bodies.
The NOVO project aims at developing novel approaches to prevent and/or degrade biofilms on catheters elongating their usage in humans up to 10 days.
Two complementary approaches for biofilm prophylaxis will be developed:
A. Ultrasonic coating of Inorganic antibiofouling agents (process developed by partner BIU) based on a single step sonochemical process to: a) Produce metal fluorides or metal oxides (e.g. MgF2, ZnO) nanoparticles (NPs) and simultaneously b) Impregnate them as antibacterial factors on the catheters. c) Co-coating with bio-inert polymer layers (containing highly hydrophilic antifouling polyethylene glycol, zwitterionic moieties or sugar-groups) grafted onto NPs of adjusted size to the size of MgF2/ZnO NPs or directly onto MgF2/ZnO NPs; to form a hydrogel layer for the protection of the MgF2/ZnO antibiofouling activity.
B. Bio/organic antibiofouling activation: 1) Novel coating for catheters based on radical catalyzed polymers to yield anti-bacterial activity. An enzymatic reaction will be applied on the phenolic compounds to generate phenolic radicals to be further polymerized on the catheter surface as an antibiofilm agent. 2) Develop and engineer Cellobiose Dehydrogenases (CDH) that actively oxidizes and degrades biofilms polysaccharides concomitantly producing stoichiometrically H2O2 as antibacterial agent. The enzymes will be coated on the catheters via a lubricant or by the Ultrasonic (US) process after their immobilization. Some novel CDH representatives already show very low activity on glucose which should be removed by further genetic engineering.'
Calafell, M.; Diaz, C.; Hadzhiyska, H.; Gibert, J.; Daga, J.; Tzanov, T. Biocatalysis and biotransformation Vol. 25, num. 2-4, p. 336-340 DOI: 10.1080/10242420701379874 Data de publicació: 2007-03 Article en revista
Cotton fabrics were dyed with dyes generated in situ by laccase-catalyzed oxidative coupling of the colorless 2,5-diaminobenzenesulfonic acid (2,5-DABSA) and 1-hydroxyphenol (catechol). The enzymatic oxidation of the dye intermediates led to cross-coupling reaction products when the reaction was conducted with an excess of catechol. At least fourfold excess of catechol was necessary to achieve satisfactory dye fixation on cotton. Formation of the same colored product using either an equimolar ratio of the reagents or tenfold excess of catechol was observed. Most probably, homo-molecular reactions predominate over the cross-coupling at equimolar ratio of the precursors, while with an excess of catechol, the cross-coupling occurs in higher yield. The reaction was followed using UV-Vis spectroscopy, HPLC, FTIR and MALDI-TOF MS. A reaction pathway for laccase-induced cross-coupling of catechol and 2,5-DABSA yielding a major colored product was proposed.