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Adsorption of chitosan solution as well as chitosan nanoparticles dispersion onto cellulose fibres was implemented at pH = 4 and 7, respectively, in order to investigate the influence of different pH values on chitosan macromolecules' conformation and consequently on its adsorption ability and resultant coating morphology, as well as on antimicrobial activity of coated fibres. Adsorption capacity, charging behaviour and electrokinetical response of fibres at different pH values were analysed by determining zeta potential. Obtained results were related to the antimicrobial activity of fibres, determined by standard ASTM E2149 method.

The main purpose of this research was to qualitatively and quantitatively identify chitosan-based viscose fibre functional group surfaces as modified by two chemically-similar phenolics, namely fisetin and quercetin. Potentiometric titration was used to determine fibre-dissociable weak acids as a consequence of the presence of chitosan and deposited flavonoids. In addition, a conventional spectrophotometric method using C.I. Acid Orange 7 dye was used for determining the amino groups only. Finally, the antioxidant and antimicrobial properties of the fibres were evaluated, respectively. It has been clearly shown that the introduction of flavonoid onto the fibres introduces a significant amount of anionic phenolic hydroxyl groups, leading to fibre antioxidant activity and a decrease in fibre antimicrobial efficiency.

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Biofilm formation triggered by uncontrolled protein adsorption, on medical devices is the leading cause of catheter-associated urinary tract infections (CAUTI) during implantation. Herein, we report a water-based, green and one-step strategy to functionalize surfaces of silicone catheters, poly(dimethylsiloxane) (PDMS), with antifouling and antimicrobial substances to avoid uncontrolled protein adsorption and microbial attachment. A novel synergetic formulation consisting of an anionic glycosaminoglycan (hyaluronic acid, HA) and a lysine-derived biocompatible cationic surfactant (N e -myristoyl-lysine methyl ester, MKM) was prepared, resulting in the formation of nanoparticles (NPs, ca. 100-250 nm). Besides their high stability and longlasting hydrophilicity in ambient and aqueous environments for 60 days, the nanometric layers (48 AE 3 nm) of HA-MKM NPs on PDMS showed no adsorption of BSA and lysozyme and substantially lower adsorption of fibrinogen as revealed by a quartz crystal microbalance with dissipation (QCM-D). In vitro antimicrobial test with S. aureus, E. coli, P. aeruginosa, P. mirabilis, C. albicans microbes under dynamic conditions revealed that the microbial growth was hampered by 85% compared with unmodified PDMS. Given the multiple functionalities, charges and diverse physiochemical properties of polysaccharide-lysine-based surfactant mixtures, this approach can be easily extended to the development of novel coatings on other silicone-based materials, thereby broadening potential applicability of PDMS-based biomaterials/devices in microfluidics, diagnostic biosensors and others. ; Tel: +43 316 380 5413 † Electronic supplementary information (ESI) available: Experimental details of DLS, QCM-D, XPS, profilometry, AFM, CLSM, potentiometric titration (for HA-MKM nanoparticles dispersion). See