Chitosan gel film bandages: correlating structure, composition, and antimicrobial properties

Chitosan gel films were successfully obtained by evaporation cast from chitosan solutions in aqueous acidic solutions of organic acids (lactic and acetic acid) as gel film bandages, with a range of additives that directly influence film morphology and porosity. We show that the structure and composition of a wide range of 128 thin gel films, is correlated to the antimicrobial properties, their biocompatibility and resistance to biodegradation. Infrared spectroscopy and solid-state 13C nuclear magnetic resonance spectroscopy was used to correlate film molecular structure and composition to good antimicrobial properties against 10 of the most prevalent Gram positive and Gram negative bacteria. Chitosan gel films reduce the number of colonies after 24 h of incubation by factors of ∼105–107 CFU/mL, compared with controls. For each of these films, the structure and preparation condition has a direct relationship to antimicrobial activity and effectiveness. These gel film bandages also show excellent stability against biodegradation with lysozyme under physiological conditions (5% weight loss over a period of 1 month, 2% in the first week), allowing use during the entire healing process. These chitosan thin films and subsequent derivatives hold potential as low-cost, dissolvable bandages, or second skin, with antimicrobial properties that prohibit the most relevant intrahospital bacteria that infest burn injuries

Towards thiol functionalization of vanadium pentoxide nanotubes using gold nanoparticles

Template-directed synthesis is a promising route to realize vanadate-based 1-D nanostructures, an example of which is the formation of vanadium pentoxide nanotubes and associated nanostructures. In this work, we report the interchange of long-chained alkyl amines with alkyl thiols. This reaction was followed using gold nanoparticles prepared by the Chemical Liquid Deposition (CLD) method with an average diameter of ∼0.9 nm and a stability of ∼85 days. V2 O5 nanotubes (VOx-NTs) with lengths of ∼2 μm and internal hollow diameters of 20-100 nm were synthesized and functionalized in a Au-acetone colloid with a nominal concentration of ∼ 4 × 1 0- 3 mol dm-3. The interchange reaction with dodecylamine is found only to occur in polar solvents and incorporation of the gold nanoparticles is not observed in the presence of n-decane

Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

This work explores the functionalization of an organic-inorganic MoS2 lamellar compound, prepared by a Chemical Liquid Deposition Method (CLD), that has an interlamellar distance of ~5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of ~85 days, and a zeta potential measured to be ζ = -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS2. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS2

Anisotropic vanadium oxide nanostructured host matrices for lithium ion intercalation

We report on unique high-volume low-dimensional V O-based turbostratic nanostructures, prepared using sol-gel synthetic methods from VO ṡ n H 2 O xerogels. Electrochemical intercalation of Li to form Li VO resulted in a maximum measured charge capacity of 1225mAh g as the β- Li VO phase. Conductivities of the order of 10 Scm were found on compressed-nanotube parallelepipedal samples, which exhibit an anisotropy factor of 70 at room temperature by preferential alignment of the nanotubes. The improved electrochemical properties observed in novel vanadium oxide nanostructured arrays are attributed to the increased volumetric density for ion intercalation, shorter diffusion paths to the intercalation sites, and a high degree of crystallinity ofthe individual nanotubular host structures

Towards thiol functionalization of vanadium pentoxide nanotubes using gold nanoparticles

Publicación ISITemplate-directed synthesis is a promising route to realize vanadate-based 1-D nanostructures, an example of which is the formation of vanadium pentoxide nanotubes and associated nanostructures. In this work, we report the interchange of long-chained alkyl amines with alkyl thiols. This reaction was followed using gold nanoparticles prepared by the Chemical Liquid Deposition (CLD) method with an average diameter of similar to 0.9 nm and a stability of similar to 85 days. V2O5 nanotubes (VOx-NTs) with lengths of similar to 2 mu m and internal hollow diameters of 20-100 nm were synthesized and functionalized in a Au-acetone colloid with a nominal concentration of similar to 4 x 10(-3) mol dm(-3). The interchange reaction with dodecylamine is found only to occur in polar solvents and incorporation of the gold nanoparticles is not observed in the presence of n-decane. (c) 2006 Elsevier Ltd. All rights reserved

Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

This work explores the functionalization of an organic–inorganic MoS2 lamellar compound, prepared by a chemical liquid deposition method (CLD), that has an interlamellar distance of 5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of 85 days, and a zeta potential measured to be z = 6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS2. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS2.The support of the FONDECYT (Grants 1050344, 1030102, 7050081), Science Foundation Ireland (SFI), PHOREMOS

Anisotropic vanadium oxide nanostructured host matrices for lithium ion intercalation

We report on unique high-volume low-dimensional V O-based turbostratic nanostructures, prepared using sol-gel synthetic methods from VO ṡ n H 2 O xerogels. Electrochemical intercalation of Li to form Li VO resulted in a maximum measured charge capacity of 1225mAh g as the β- Li VO phase. Conductivities of the order of 10 Scm were found on compressed-nanotube parallelepipedal samples, which exhibit an anisotropy factor of 70 at room temperature by preferential alignment of the nanotubes. The improved electrochemical properties observed in novel vanadium oxide nanostructured arrays are attributed to the increased volumetric density for ion intercalation, shorter diffusion paths to the intercalation sites, and a high degree of crystallinity ofthe individual nanotubular host structures