An antimicrobial polymeric bilayer structure based on the application of an acrylic coating containing hollow zinc oxide nanotubes over a polymeric substrate was developed in this work. Firstly, zinc oxide nanotubes (ZnO NT ) were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers followed by polymer removal through calcination with the purpose of obtaining antimicrobial nanostructures with a high specific area. Parameters of electrospinning, ALD, and calcination processes were set in order to obtain successfully hollow zinc oxide nanotubes. Morphological studies through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopies confirmed the morphological structure of ZnO NT with an average diameter of 180 nm and thickness of approximately 60 nm. Thermal and X-ray diffraction (XRD) analyses provided evidence that calcination completely removed the polymer, resulting in a crystalline hexagonal wurtzite structure. Subsequently, ZnO NT were incorporated into a polymeric coating over a polyethylene extruded film at two concentrations: 0.5 and 1 wt. % with respect to the polymer weight. An antimicrobial analysis of developed antimicrobial materials was performed following JIS Z2801 against Staphylococcus aureus and Escherichia coli. When compared to active materials containing commercial ZnO nanoparticles, materials containing ZnO NT presented higher microbial inhibition principally against Gram-negative bacteria, whose reduction was total for films containing 1 wt. % ZnO NT . Antiviral studies were also performed, but these materials did not present significant viral reduction.Nanomaterials 2020, 10, 503 2 of 14 antimicrobial nanostructures are one of the most promising alternatives in the search for new antimicrobial substances [3][4][5]. The attention has been principally centered on metallic/metal oxide nanoparticles due to their broad antibacterial and antifungal activities at low concentrations thanks to their high specific area [6][7][8][9].Zinc oxide (ZnO) nanoparticles are an inorganic material with optical, chemical sensing, electric conductivity, catalytic, photochemical, and antimicrobial properties. This metal oxide presents three crystal structures: wurtzite, zinc blend, and rocksalt, with a direct wide band gap of 3.3 Ev [10]. Some works have evidenced ZnO nanoparticles with dimensions smaller than 100 nm have shown increasing antimicrobial properties against Gram-negative and Gram-positive bacteria due to a higher cellular internalization. Specifically, Verma et al. (2018) studies have indicated that the antibacterial activity of ZnO nanoparticles against Staphylococcus aureus and Escherichia coli increased with the decrease in their size from 250 to 80, 40, and 20 nm due to an increased reactive oxygen species generation and membrane damage in bacteria [11,12]. Different synthesis methods as sol-gel, hydrothermal, simple thermal sublimation, vapor-liquid-solid, double-jet precipitation, self-combustion, and "green synthes...

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carbon-metal-based composites arise as advanced materials in the frontiers with nanotechnology, since the properties inherent to each component are multiplexed into a new material with potential applications. in this work, a novel composite consisting of randomly oriented permalloy nanowires (py nWs) intercalated among the sheets of multi-layered graphene oxide (Go) was performed. py nWs were synthesized by electrodeposition inside mesoporous alumina templates, while Go sheets were separated by means of sonication. Sequential deposition steps of Py NWs and GO flakes allowed to reach a reproducible and stable graphene oxide-based magnetic assembly. Microscopic and spectroscopic results indicate that py nWs are anchored on the surface as well as around the edges of the multi-layered Go, promoted by the presence of chemical groups, while magnetic characterization affords additional support to our hypothesis regarding the parallel orientation of the Py NWs with respect to the GO film, and also hints the parallel stacking of GO sheets with respect to the substrate. the most striking result remains on the electrochemical performance achieved by the composite that evidences an enhanced conductive behaviour compared to a standard electrode. Such effect provides an approach to the development of permalloy nanowires/graphene oxide-based electrodes as attractive candidates for molecular sensing devices. Composite materials arise as versatile candidates that could be designed to satisfy diverse technological applications due to their multifunctional behaviour. Since composites are obtained by combining two or more materials that have different attributes, such assembly provides to the composite of unique properties. In fact, several examples exist that have demonstrated the industrial development behind their production, being the concrete a well-known composite, where its strength under compression is improved by adding metal rods, wires, mesh or cables in order to create reinforced concrete. Most of the current composites have been made by carbon allotropes 1, 2. In particular, when graphene is combined with the metallic copper, a new material around 500 times stronger than copper is achieved 3. Likewise, composites constituted by graphene and nickel yield a strength larger than 180 times of nickel 4. A soft Ni-rich ferromagnet 5, 6 , that is widely employed as a magnetic core material in diverse technological applications, such as magnetic recording heads 7-9 , microinductors and magnetoresistive random access memories (MRAM) 10, 11 , is the so called permalloy (Py), an alloy with about 20% iron and 80% nickel content. On the one hand, bulk Py exhibits large magnetic permeability, enhanced sensitivity in sensing devices 12 , as well as low coercivity and remanence, of interest in magnetic shielding 13. In addition, it is a material with nearly zero magnetostriction, an attribute that promotes an easier integration in different devices 13. Besides, the high Ni content provides an excellent corrosion resistance to the alloy...

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