Antibacterial properties of polypyrrole-treated fabrics by ultrasound deposition.

Antimicrobial textiles can contribute to the fighting against antibiotic resistance pathogenic microorganisms. Polypyrrole is a conjugated polymer that exerts a biocidal action thanks to positive charges on its backbone chain produced during it synthesis. In this work, dispersions of stable polypyrrole nanoparticles were produced by chemical oxidative polymerization at room temperature in water. An ultrasound-assisted coating process was then used to effectively treat a polyester fabric with the nanoparticles to obtain an optimal antibacterial coating which efficiently eradicates the bacteria. The results showed that the treated fabric with about 4 g/m2 of polypyrrole had log bacteria reductions of 6.0 against Staphylococcus aureus and 7.5 against Escherichia coli. The combination of a polypyrrole synthesis in the form of water nanoparticles dispersions and a continuous coating of fabrics supported by ultrasound overcomes some issues of upscaling of the traditional in-situ chemical deposition used until now for the production of polypyrrole-coated textiles.

Electrospun Lipid Binding Proteins Composite Nanofibers with Antibacterial Properties.

Electrospinning is here used for the first time to prepare nanofibers including a host/guest complex in a keratin/poly(ethylene oxide) matrix. The host is a lipid binding protein and the guest is an insoluble bactericidal molecule, irgasan, bound within the protein internal cavity. The obtained nanofibers, characterized by scanning electron microscopy, exhibit excellent antibacterial activity toward Gram positive and negative bacteria, even with a moderate protein/irgasan cargo. Solution NMR studies, employed to provide molecular information on the cargo system, points to a micromolar affinity, compatible with both the electrospinning process and slow guest release. The versatility of the carrier protein, capable of interacting with a variety of druggable hydrophobic molecules, is exploitable for the development of innovative biomedical devices, whose properties can be tuned by the selected guest.

Intrinsic intumescent-like flame retardant properties of DNA-treated cotton fabrics.

In the present work, the effect of different DNA add-ons (namely, 5, 10 and 19 wt.%) has been thoroughly investigated as far as the flammability and the resistance to an irradiating heat flux of 35 or 50 kW/m(2) are considered. The results have shown that 10 wt.% is the minimum amount that allows reaching the self-extinguishment of cotton when a methane flame is applied. Furthermore, only 19 wt.% is able to confer resistance to the fabric towards an irradiating heat flux of 35 kW/m(2): indeed, the specimens tested under the cone calorimetry do not burn. Measurements of temperature runs as a function of time have clearly indicated that cotton, instead of burning, pyrolyses: indeed, because of the protective role exerted by DNA molecules, the deposited coatings have turned out to absorb heat, form char and induce its formation on the fabric, and finally to release inert gases.

Thermal stability and flame resistance of cotton fabrics treated with whey proteins.

It is well described in the literature that whey proteins are able to form coatings, which exhibit high mechanical and oxygen barrier properties, notwithstanding a great water vapour adsorption. These peculiarities have been exploited for applying a novel protein-based finishing treatment to cotton and for assessing the protein effect on the thermal and thermo-oxidative stability and on the flame retardant properties of the cellulosic fabric. Indeed, the deposited whey protein coatings have turned out to significantly affect the thermal degradation of cotton in inert and oxidative atmosphere, and to somehow modify its combustion when a flame has been applied. Furthermore, the influence of the secondary and tertiary structure of these proteins on the morphology of the deposited coating, and thus on the thermal and flame retardant properties of the treated fabrics, has been evaluated by performing a denaturation thermal treatment before the protein application.