Integrating an antimicrobial nanocomposite to bioactive electrospun fibers for improved wound dressing materials.

This study investigates the fabrication and characterization of electrospun poly (ε-caprolactone)/poly (vinyl pyrrolidone) (PCL/PVP) fibers integrated with a nanocomposite of chitosan, silver nanocrystals, and graphene oxide (ChAgG), aimed at developing advanced wound dressing materials. The ChAgG nanocomposite, recognized for its antimicrobial and biocompatible properties, was incorporated into PCL/PVP fibers through electrospinning techniques. We assessed the resultant fibers' morphological, physicochemical, and mechanical properties, which exhibited significant enhancements in mechanical strength and demonstrated effective antimicrobial activity against common bacterial pathogens. The findings suggest that the PCL/PVP-ChAgG fibers maintain biocompatibility and facilitate controlled therapeutic delivery, positioning them as a promising solution for managing chronic and burn-related wounds. This study underscores the potential of these advanced materials to improve healing outcomes cost-effectively, particularly in settings plagued by high incidences of burn injuries. Further clinical investigations are recommended to explore these innovative fibers' full potential and real-world applicability.

Antibacterial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG) development for its potential use in bioactive wound dressings.

An adequate wound dressing reduces time of healing, provides cost-effective care, thereby improving patients' quality life. An antimicrobial bioactivity is always desired, for that reason, the objective of this work is to design an antimicrobial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG). ChAgG nanostructured composite material is composed of chitosan from corn (Ch), and silver nanocrystals from garlic (Allium sativum). The nanocomposite obtained is the result of a series of experiments combining the graphene oxide (GrOx) with two members of the Amaryllidaceae family; garlic and onion (Allium cebae), which contain different sulfur materials. The characterization arrays confirmed the successful production of silver crystal, graphene oxidation and the blending of both components. The role of the chitosan as a binder between graphene and silver nanocrystals is proved. Moreover, the study discusses garlic as an optimal source that permits the synthesis of silver nanocrystals (AgNCs) (⁓ 2 to 10 nm) with better thermal and crystallinity properties. It was also confirmed the successful production of the ChAgG nanocomposite. Escherichia coli and Staphylococcus aureus were used to demonstrate the antibacterial bioactivity and L-929 fibroblast cells were utilized to visualize their biocompatibility. The proposed ChAgG nanomaterial will be useful for functionalizing specific fiber network that represents current challenging research in the fabrication of bioactive wound dressings.

Hydrodesulfurization of Dibenzothiophene over Ni-Mo-W Sulfide Catalysts Supported on Sol-Gel Al2O3-CeO2.

To achieve sulfur content in gas oil at a near-zero level, new catalysts with improved hydrogenation functions are needed. In this work, new Ni-Mo-Mo hydrodesulfurization (HDS) catalysts supported by Al2O3-CeO2 materials were synthesized to evaluate their efficiency in the reaction of HDS with dibenzothiophene (DBT). Al2O3-CeO2 supports different CeO2 loadings (0, 5, 10 and 15 wt.%) and supported NiMoW catalysts were synthesized by sol-gel and impregnation methods, respectively. The physicochemical properties of the supports and catalysts were determined by a variety of techniques (chemical analysis, XRD, N2 physisorption, DRS UV-Vis, XPS, and HRTEM). In the DBT HDS reaction carried out in a batch reactor at 320 °C and a H2 pressure of 5.5 MPa, the sulfide catalysts showed a dramatic increase in activity with increasing CeO2 content in the support. Nearly complete DBT conversion (97%) and enhanced hydrogenation function (HYD) were achieved on the catalyst with the highest CeO2 loading. The improved DBT conversion and selectivity towards the hydrogenation products (HYD/DDS ratio = 1.6) of this catalyst were attributed to the combination of the following causes: (i) the positive effect of CeO2 in forcing the formation of the onion-shaped Mo(W)S2 layers with a large number of active phases, (ii) the inhibition of the formation of the undesired NiAlO4 spinel phase, (iii) the appropriate textural properties, (iv) the additional ability for heterolytic dissociation of H2 on the CeO2 surfaces, and (v) the increase in Brønsted acidity.

Stability of Non-Concentric, Multilayer, and Fully Aligned Porous MoS2 Nanotubes.

Nanotubes made of non-concentric and multiple small layers of porous MoS2 contain inner pores suitable for membrane applications. In this study, molecular dynamics simulations using reactive potentials were employed to estimate the stability of the nanotubes and how their stability compares to macroscopic single- (1L) and double-layer MoS2 flakes. The observed stability was explained in terms of several analyses that focused on the size of the area of full-covered layers, number of layers, polytype, and size of the holes in the 1L flakes. The reactive potential used in this work reproduced experimental results that have been previously reported, including the small dependency of the stability on the polytype, the formation of S-S bonds between inter- and intra-planes, and the limit of stability for two concentric rings forming a single ring-like flake.

Bimetallic Niobium-Based Catalysts Supported on SBA-15 for Hydrodeoxygenation of Anisole.

The effect of adding iron, cobalt or nickel to a prepared niobium-supported catalyst using mesoporous silica SBA-15 as a support was evaluated in the hydrodeoxygenation (HDO) reaction of anisole, chosen as a model compound in lignocellulosic biomass derived bio-oil. HDO activity as well as selectivity toward O-free products were highly dependent on the catalyst formulation: Ni incorporation showed the highest anisole conversion and selectivity to deoxygenated products, followed by Co and Fe counterparts. The activity was explained in terms of acidity, metal surface exposure and reducibility as a function of the interaction between the phases present. Regarding the characterization results, the better performance of NiNb/SBA-15 was associated with its lower acidity, higher Nb/Si surface exposure, NbO2/Nb2O5 ratio and better interaction between Ni and Nb species.

Sol gel-derived SBA-16 mesoporous material.

The aim of this article is to review current knowledge related to the synthesis and characterization of sol gel-derived SBA-16 mesoporous silicas, as well as a review of the state of the art in this issue, to take stock of knowledge about current and future applications. The ease of the method of preparation, the orderly structure, size and shape of their pores and control, all these achievable through simple changes in the method of synthesis, makes SBA-16 a very versatile material, potentially applicable in many areas of science and molecular engineering of materials.

SBA-15 Mesoporous Silica as Catalytic Support for Hydrodesulfurization Catalysts-Review.

SBA-15 is an interesting mesoporous silica material having highly ordered nanopores and a large surface area, which is widely employed as catalyst supports, absorbents, drug delivery materials, etc. Since it has a lack of functionality, heteroatoms and organic functional groups have been incorporated by direct or post-synthesis methods in order to modify their functionality. The aim of this article is to review the state-of-the-art related to the use of SBA-15-based mesoporous systems as supports for hydrodesulfurization (HDS) catalysts.