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New antimicrobial (AM) coatings based on imidazolium salts have been prepared linking the imidazolium salts to the cotton fabric using siloxane oligomers as coupling agents. Three different imidazolium salts, linked to the siloxane oligomers connected to the cotton fabric either with ionic or covalent linkages, have been used. FTIR analysis shows that the imidazolium salts are linked to the cotton fabric. All the coatings prepared have high antimicrobial activity at both concentrations tested (3 and 10 wt%) and against a Gram positive and a Gram negative bacterium. The AM activity is mainly retained after 4 cycles of washing. [ABSTRACT FROM AUTHOR]

The photocatalytic effect of TiO2 has great potential for the disinfection of surfaces. Most studies reported in the literature use UV activation of TiO2, while visible light has been used only in a few applications. In these studies, high concentrations of TiO2, which can compromise surface properties, have been used. In this work, we have developed an acrylic-water paint dispersion containing low TiO2 content (2 vol %) for the inactivation of microorganisms involved in hospital-acquired infections. The nanoparticles and the coating have been characterized using spectroscopic techniques and transmission electron microscopy, showing their homogenous dispersion in the acrylic urethane coating. A common fluorescent light source was used to activate the photocatalytic activity of TiO2. The paint dispersion showed antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The coating containing the TiO2 nanoparticles maintained good UV stability, strong adhesion to the substrate and high hardness. Therefore, the approach used is feasible for paint formulation aimed at disinfection of healthcare surfaces. [ABSTRACT FROM AUTHOR]

Highlights: [•] Castor oil-derivatives are employed for the synthesis of bio-based polyesters. [•] Polyesters obtained from ricinoleic acid exhibit high biocidal activity. [•] Double bonds are exploited for grafting reaction to improve biocidal properties. [Copyright &y& Elsevier]

Abstract: Imidazolium poly(butylene terephthalate) ionomers with ionic groups located randomly along the polymer chain or selectively as end-groups (telechelic) have been prepared in order to determine their antimicrobial (AM) activity. Two different approaches have been followed for the linkage of the imidazolium to the polymer backbone: a covalent bond and an ionic aggregation to sulfonated groups covalently bonded to the polymer. The ionic groups have been linked to the polymer in order to improve the long-term AM activity since the low molecular weight additives commonly used tends to migrate toward the surface during use. We have found that imidazolium ionomers present AM activity comparable with that of commercial antimicrobial agents such as Triclosan. The AM activity depends on the polymer architecture, the telechelic approach being more active compared to the random approach. We have proved that imidazolium ionomers retain their high AM activity even after 6 days in water at 60 °C while Triclosan consistently loses his activity. [Copyright &y& Elsevier]

The growing concern on the antibiotic resistance spreading among bacteria has stimulated the search for valuable alternatives from plant sources. This study dealt with the potential use of hemp (Cannabis sativa L.) seeds extract to inhibit the growth of selected pathogenic enterobacteria and the biofilm formation by Staphylococcus aureus , representing severe risks of food-borne illnesses. Effects on probiotic bacteria were also examined. A double-staining viability/mortality assay was used to examine potential S. aureus membrane damage. Our results highlighted a selective antimicrobial activity of C. sativa extract against pathogenic strains and no inhibitory effects on the growth of probiotic strains belonging to the Bifidobacterium and Lactobacillus genera. This selective inhibition is of outmost importance for the maintenance of healthy gut microbiota. The double-staining assay showed that the C. sativa extract was capable of inhibiting the biofilm producer S. aureus ATCC 35556 strain; this antibacterial action was only partially linked to membrane damage. Biofilm formation was inhibited as well; inhibition occurs at lower concentration with respect to planktonic cells (0.5 mg/ml vs 1 mg/ml, respectively). Therefore, hemp seeds extracts represent a new exploitable and valuable antimicrobial and antibiofilm agent for the food and nutraceutical industry as a possible alternative to antibiotics/antibacterial compounds. Image 1 • Cannabis sativa L. seeds showed antimicrobial and antibiofilm activity. • C. sativa L. seeds selectively inhibit the growth of potentially pathogenic strains. • C. sativa L. seeds did not exert antimicrobial activity against probiotic bacteria. • C. sativa L. seeds inhibit the biofilm formation by Staphylococcus aureus. [ABSTRACT FROM AUTHOR]