One-step room-temperature synthesis of nanocrystalline Mn3O4 hausmannite, without heating posttreatment, was carried out from a simple dissolution of manganese(II) acetate in a mixture of ...N,N'-dimethylformamide (DMF) and water. Homogeneous nanocrystals like rods were obtained, with an average width and length of 6.6+/-1.2 nm and 17.4+/-4.1 nm, respectively, and a preferential growth along the 001 direction. Magnetization measurements on a powdered sample showed ferrimagnetic behavior at low temperatures. Under zero-field cooling (ZFC) measurement at 100 Oe, the observed blocking temperature (T(B)) was 37 K.
This work presents the deposition and study of the semiconductor behavior of CuBi2O4 nanoparticles (NPs) with an average crystallite size of 24 ± 2 nm embedded in poly(3,4 ethylene ...dioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) films. The CuBi2O4 NP bandgap was estimated at 1.7 eV, while for the composite film, it was estimated at 2.1 eV, due to PEDOT:PSS and the heterojunction between the polymer and the NPs. The charge transport of the glass/ITO/PEDOT:PSS-CuBi2O4 NP/Ag system was studied under light and dark conditions by means of current–voltage (I–V) characteristic curves. In natural-light conditions, the CuBi2O4 NPs presented electric behavior characterized by three different mechanisms: at low voltages, the behavior follows Ohm’s law; when the voltage increases, charge transport occurs by diffusion between the NP–polymer interfaces; and at higher voltages, it occurs due to the current being dominated by the saturation region. Due to their crystalline structure, their low bandgap in films and the feasibility of integrating them as components in composite films with PEDOT:PSS, CuBi2O4 NPs can be used as parts in optoelectronic devices.
This study presents an in vitro analysis of the bactericidal and cytotoxic properties of hybrid films containing nickel oxide (NiO) and nickel ferrite (NiFe2O4) nanoparticles embedded in ...polypropylene (PP). The solvent casting method was used to synthesize films of PP, PP@NiO, and PP@NiFe2O4, which were characterized by different spectroscopic and microscopic techniques. The X-ray diffraction (XRD) patterns confirmed that the small crystallite sizes of NiO and NiFe2O4 NPs were maintained even after they were incorporated into the PP matrix. From the Raman scattering spectroscopy data, it was evident that there was a significant interaction between the NPs and the PP matrix. Additionally, the Scanning Electron Microscopy (SEM) analysis revealed a homogeneous dispersion of NiO and NiFe2O4 NPs throughout the PP matrix. The incorporation of the NPs was observed to alter the surface roughness of the films; this behavior was studied by atomic force microscopy (AFM). The antibacterial properties of all films were evaluated against Pseudomonas aeruginosa (ATCC®: 43636™) and Staphylococcus aureus (ATCC®: 23235™), two opportunistic and nosocomial pathogens. The PP@NiO and PP@ NiFe2O4 films showed over 90% bacterial growth inhibition for both strains. Additionally, the effects of the films on human skin cells, such as epidermal keratinocytes and dermal fibroblasts, were evaluated for cytotoxicity. The PP, PP@NiO, and PP@NiFe2O4 films were nontoxic to human keratinocytes. Furthermore, compared to the PP film, improved biocompatibility of the PP@NiFe2O4 film with human fibroblasts was observed. The methodology utilized in this study allows for the production of hybrid films that can inhibit the growth of Gram-positive bacteria, such as S. aureus, and Gram-negative bacteria, such as P. aeruginosa. These films have potential as coating materials to prevent bacterial proliferation on surfaces.
This study presents an in vitro analysis of the bactericidal and cytotoxic properties of hybrid films containing nickel oxide (NiO) and nickel ferrite (NiFesub.2Osub.4) nanoparticles embedded in ...polypropylene (PP). The solvent casting method was used to synthesize films of PP, PP@NiO, and PP@NiFesub.2Osub.4, which were characterized by different spectroscopic and microscopic techniques. The X-ray diffraction (XRD) patterns confirmed that the small crystallite sizes of NiO and NiFesub.2Osub.4 NPs were maintained even after they were incorporated into the PP matrix. From the Raman scattering spectroscopy data, it was evident that there was a significant interaction between the NPs and the PP matrix. Additionally, the Scanning Electron Microscopy (SEM) analysis revealed a homogeneous dispersion of NiO and NiFesub.2Osub.4 NPs throughout the PP matrix. The incorporation of the NPs was observed to alter the surface roughness of the films; this behavior was studied by atomic force microscopy (AFM). The antibacterial properties of all films were evaluated against Pseudomonas aeruginosa (ATCCsup.®: 43636™) and Staphylococcus aureus (ATCCsup.®: 23235™), two opportunistic and nosocomial pathogens. The PP@NiO and PP@ NiFesub.2Osub.4 films showed over 90% bacterial growth inhibition for both strains. Additionally, the effects of the films on human skin cells, such as epidermal keratinocytes and dermal fibroblasts, were evaluated for cytotoxicity. The PP, PP@NiO, and PP@NiFesub.2Osub.4 films were nontoxic to human keratinocytes. Furthermore, compared to the PP film, improved biocompatibility of the PP@NiFesub.2Osub.4 film with human fibroblasts was observed. The methodology utilized in this study allows for the production of hybrid films that can inhibit the growth of Gram-positive bacteria, such as S. aureus, and Gram-negative bacteria, such as P. aeruginosa. These films have potential as coating materials to prevent bacterial proliferation on surfaces.
This work focuses on the obtaining and the bactericidal properties study, in vitro, of hybrid films as potential coating materials to inhibit bacteria proliferation. In consequence, hybrid films from ...nickel oxide (NiO) and nickel ferrite (NiFe
2
O
4
) nanoparticles (NPs) embedded in poly-3-hydroxybutyrate (P3HB) were obtained by the solvent casting method. P3HB@NiO and P3HB@NiFe
2
O
4
hybrid films and P3HB film were characterized by X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM). The XRD of the hybrid films showed that NiO and NiFe
2
O
4
NPs incorporated in the P3HB conserved their nanometric size, and by Energy-dispersive X-ray spectroscopy (EDS) were observed that NPs are homogeneously distributed in the films. The bactericidal effect of the obtained films was evaluated in vitro from the broth surface method against two opportunistic and nosocomial pathogens,
Staphylococcus aureus
and
Pseudomonas aeruginosa
. The results showed that P3HB film, P3HB@NiO, and P3HB@NiFe
2
O
4
hybrid films reduced 90%, 98%, and 97% of the growth of
S. aureus
, respectively. For
P. aeruginosa,
their growth was reduced by 90%, 94%, and 96%, respectively. In addition, the cytotoxic effect of NiO and NiFe
2
O
4
NPs, as well as P3HB film, and P3HB@NiO, and P3HB@NiFe
2
O
4
hybrid films was evaluated using human skin cells; keratinocytes and fibroblast, being the NPs less cytotoxic than films. Although P3HB is known as a biocompatible polymer, here is demonstrated that in our work conditions, their films have bactericidal properties and are cytotoxic to keratinocytes and fibroblasts, the first barrier of the human skin. However, the P3HB@NiO and P3HB@NiFe
2
O
4
hybrid films synergize the bactericidal effect between the P3HB and the NPs. On the other hand, the NPs decrease the P3HB cytotoxicity to keratinocytes. The methodology used in this work is particularly suitable for producing hybrid films with antibacterial activity against Gram-positive and Gram-negative bacterial strains.
Debido al creciente interés en la síntesis de diferentes estructuras a escala nanométrica, las alúminas anódicas porosas son una alternativa emergente a los métodos más sofisticados y costosos que se ...utilizan actualmente. En este trabajo se presenta una breve revisión acerca de algunos resultados experimentales recientes para sintetizar alúminas anódicas porosas con diámetros de poro extra grandes (>200 nm), usando mezclas de ácidos como electrolitos y voltajes altos de anodizado. Adicionalmente, se presentan estudios relacionados con la estabilidad térmica de las alúminas anódicas porosas, formadas en condiciones estándar, usando los electrolitos más comunes (ácidos sulfúrico, oxálico y fosfórico). Dichos estudios han mostrado que la alúmina anódica, de inicio amorfa, debe transitar por un proceso de eliminación de aniones previo a la transformación de fases policristalinas hasta alcanzar la fase más estable, α-alúmina. Finalmente, se mencionan algunas de las más destacadas aplicaciones que podrían tener las nanoestructuras obtenidas a partir de alúminas anódicas porosas obtenidas por métodos no convencionales y las tratadas térmicamente.
This study presents an in vitro analysis of the bactericidal and cytotoxic properties of hybrid films containing nickel oxide (NiO) and nickel ferrite (NiFe
O
) nanoparticles embedded in ...polypropylene (PP). The solvent casting method was used to synthesize films of PP, PP@NiO, and PP@NiFe
O
, which were characterized by different spectroscopic and microscopic techniques. The X-ray diffraction (XRD) patterns confirmed that the small crystallite sizes of NiO and NiFe
O
NPs were maintained even after they were incorporated into the PP matrix. From the Raman scattering spectroscopy data, it was evident that there was a significant interaction between the NPs and the PP matrix. Additionally, the Scanning Electron Microscopy (SEM) analysis revealed a homogeneous dispersion of NiO and NiFe
O
NPs throughout the PP matrix. The incorporation of the NPs was observed to alter the surface roughness of the films; this behavior was studied by atomic force microscopy (AFM). The antibacterial properties of all films were evaluated against
(ATCC
: 43636™) and
(ATCC
: 23235™), two opportunistic and nosocomial pathogens. The PP@NiO and PP@ NiFe
O
films showed over 90% bacterial growth inhibition for both strains. Additionally, the effects of the films on human skin cells, such as epidermal keratinocytes and dermal fibroblasts, were evaluated for cytotoxicity. The PP, PP@NiO, and PP@NiFe
O
films were nontoxic to human keratinocytes. Furthermore, compared to the PP film, improved biocompatibility of the PP@NiFe
O
film with human fibroblasts was observed. The methodology utilized in this study allows for the production of hybrid films that can inhibit the growth of Gram-positive bacteria, such as
, and Gram-negative bacteria, such as
. These films have potential as coating materials to prevent bacterial proliferation on surfaces.
In the present work, oxalic amorphous porous anodic alumina membranes with highly ordered porous arrays and average nanometric porous dimensions of 70 nm in diameter and 17 microns in depth ...(nanotubes) were prepared and successfully used as host matrix for fluorinated bent-core liquid crystals. Atomic force microscopy studies were performed on the organic-inorganic hybrid samples in order to explore surface morphology and optimal insertion of these liquid crystalline (LC)-compounds into this environment. The quadratic nonlinear optical (NLO) and spectroscopic properties of the implemented mesogen with the nanotube-like confinement were systematically studied in order to evaluate its optical performance. Bent core molecules have shown interesting optical properties which have not yet been intensively investigated in solid-state hybrid structures. Hence, the obtained hybrid composites represent a promising field of investigation in the route to functional bent-core based materials, where different bent-core mesomorphic structures can be obtained and are of interest for new and improved applications in nanotechnology.
A novel one step room temperature synthesis of nanocrystalline Mn3O4 hausmannite was carried out from a simple dissolution of manganese(II) acetate, in a mixture of N,N'-dimethylformamide (DMF) and ...water. Homogeneous nanocrystals like rods were obtained, with an average width and length of 6.6 - 1.2 nm and 17.4 - 4.1 nm respectively, and a preferential growth along the < 001 > direction. Magnetization measurements on a powdered sample showed a ferrimagnetic behavior at low temperature. The blocking temperature (TB) was observed at 37K and the Curie temperature (Tc) at 40K.
Prepared amorphous porous anodic alumina with average nanometric porous dimensions of 67
nm in diameter and 50
μm in depth was successfully used as host network for different liquid crystalline ...azobenzene compounds bearing oligo(ethylene glycol) segments. Since the implemented optical chromophores were specifically designed for quadratic non-linear optical applications, the obtained ordered hybrid structures were fully characterized according to the second harmonic generation technique following the Maker-Fringes method. Comparative linear optical absorption, Raman and X-ray photoelectron spectroscopic investigations were also carried out in order to evaluate the optical performance of these molecular systems within the 1D-nanotube-like confinement. Finally, atomic force microscopic studies of both the dissolved barrier layer and the porous cap were performed on the samples in order to explore surface morphology and assure best possible insertion of these azo-dyes within the pores of anodic alumina.
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