Exploring the Use of Amine Modified Mesoporous Magnesium Carbonate for the Delivery of Salicylic Acid in Topical Formulations: In Vitro Cytotoxicity and Drug Release Studies

Salicylic acid (SA) has for a long time been used to treat various skin disorders due to its anti-inflammatory, bacteriostatic, and antifungal properties. In the present work, mesoporous magnesium carbonate (MMC), a promising drug carrier, was modified with 3-aminopropyl-triethoxysilane to enable loading of SA. The amine modified MMC (aMMC) was successfully loaded with 8 wt.% of SA via a solvent evaporation method. SA was later completely released from the carrier in less than 15 min. Furthermore, the cytotoxicity of the functionalized material was evaluated. aMMC was found to be non-toxic for human dermal fibroblast cells with particle concentration of up to 1000 µg/mL when exposed for 48 h. The presented results form the basis of future development of aMMC as a potential carrier for SA in dermatological applications.

The thermoelectric properties of Au nanoparticle-incorporated Al-doped mesoporous ZnO thin films

Mesoporous Al-doped ZnO thin films incorporated with gold nanoparticles (Au NPs) were synthesized using a sol-gel and evaporation-induced self-assembly process. In this study, the complementary effects of Au NP incorporation and Al doping on the thermoelectric properties of mesoporous ZnO thin films were analysed. The incorporated Au NPs induced an increase in electrical conductivity but a detriment in the pore arrangement of the mesoporous ZnO thin film, which was accompanied by a decrease in porosity. However, the addition of the Al dopant minimized the pore structural collapse because of the inhibition of the grain growth in the ZnO skeletal structure, resulting in the enhancement of the pore arrangement and porosity. When the Au NPs and Al dopant were added at the same time, the degradation in the pore structure was minimized and the electrical conductivity was effectively increased, but the absolute value of the Seebeck coefficient was decreased. However, as a result, the thermoelectric power factor was increased by 2.4 times compared to that of the pristine mesoporous ZnO thin film. It was found that co-introducing the Au NPs and Al doping to the mesoporous ZnO structure was effective in preserving the pore structure and increasing the electric conductivity, thereby enhancing the thermoelectric property of the mesoporous ZnO thin film.

Facile synthesis of reduced graphene oxide by modified Hummer's method as anode material for Li-, Na- and K-ion secondary batteries

Reduced graphene oxide (rGO) sheets were synthesized by a modified Hummer's method without additional reducing procedures, such as chemical and thermal treatment, by appropriate drying of graphite oxide under ambient atmosphere. The use of a moderate drying temperature (250°C) led to mesoporous characteristics with enhanced electrochemical activity, as confirmed by electron microscopy and N₂ adsorption studies. The dimensions of the sheets ranged from nanometres to micrometres and these sheets were entangled with each other. These morphological features of rGO tend to facilitate the movement of guest ions larger than Li⁺. Impressive electrochemical properties were achieved with the rGO electrodes using various charge-transfer ions, such as Li⁺, Na⁺ and K⁺, along with high porosity. Notably, the feasibility of this system as the carbonaceous anode material for sodium battery systems is demonstrated. Furthermore, the results also suggest that the high-rate capability of the present rGO electrode can pave the way for improving the full cell characteristics, especially for preventing the potential drop in sodium-ion batteries and potassium-ion batteries, which are expected to replace the lithium-ion battery system.

Increased Flexibility in Polyimide Aerogels Using Aliphatic Spacers in the Polymer Backbone

Polyimide aerogels are mechanically strong porous solids with high surface area, low density, and dielectric constants close to 1, making them ideal materials for use as substrates for lightweight antennas. Increasing the flexibility of the polyimide aerogels extends the usefulness for conformal antennas for use on small aircraft such as unmanned air vehicles or personal air mobility vehicles. To this end, polyimide aerogels made with aromatic amines with 4-10 methylene units as flexible spacers between aromatic rings in the backbone have been fabricated. Substituting 25-75 mol % of fully aromatic 2,2'-dimethylbenzidine with these flexible diamines increases the flexibility of polyimide aerogels, making them bendable at thicknesses up to 2-3 mm. The density, dielectric constants, thermal and moisture stability, and mechanical properties of these aerogels were assessed to understand the effect of the amount and length of the methylene spacers on these properties.

A perspective on magnetic core-shell carriers for responsive and targeted drug delivery systems

Magnetic core-shell nanocarriers have been attracting growing interest owing to their physicochemical and structural properties. The main principles of magnetic nanoparticles (MNPs) are localized treatment and stability under the effect of external magnetic fields. Furthermore, these MNPs can be coated or functionalized to gain a responsive property to a specific trigger, such as pH, heat, or even enzymes. Current investigations have been focused on the employment of this concept in cancer therapies. The evaluation of magnetic core-shell materials includes their magnetization properties, toxicity, and efficacy in drug uptake and release. This review discusses some categories of magnetic core-shell drug carriers based on Fe2O3 and Fe3O4 as the core, and different shells such as poly(lactic-co-glycolic acid), poly(vinylpyrrolidone), chitosan, silica, calcium silicate, metal, and lipids. In addition, the review addresses their recent potential applications for cancer treatment.

Mesopore-Induced Ultrafast Na+ -Storage in T-Nb2 O5 /Carbon Nanofiber Films toward Flexible High-Power Na-Ion Capacitors

Hybrid Na-ion capacitors (NICs) are receiving considerable interest because they combine the merits of both batteries and supercapacitors and because of the low-cost of sodium resources. However, further large-scale deployment of NICs is impeded by the sluggish diffusion of Na⁺ in the anode. To achieve rapid redox kinetics, herein the controlled fabrication of mesoporous orthorhombic-Nb₂ O₅ (T-Nb₂ O₅ )/carbon nanofiber (CNF) networks is demonstrated via in situ SiO₂ -etching. The as-obtained mesoporous T-Nb₂ O₅ (m-Nb₂ O₅ )/CNF membranes are mechanically flexible without using any additives, binders, or current collectors. The in situ formed mesopores can efficiently increase Na⁺ -storage performances of the m-Nb₂ O₅ /CNF electrode, such as excellent rate capability (up to 150 C) and outstanding cyclability (94% retention after 10 000 cycles at 100 C). A flexible NIC device based on the m-Nb₂ O₅ /CNF anode and the graphene framework (GF)/mesoporous carbon nanofiber (mCNF) cathode, is further constructed, and delivers an ultrahigh power density of 60 kW kg^-1 at 55 Wh kg^-1 (based on the total weight of m-Nb₂ O₅ /CNF and GF/mCNF). More importantly, owing to the free-standing flexible electrode configuration, the m-Nb₂ O₅ /CNF//GF/mCNF NIC exhibits high volumetric energy and power densities (11.2 mWh cm^-3 , 5.4 W cm^-3 ) based on the full device, which holds great promise in a wide variety of flexible electronics.

Sulfur Doping: Unique Strategy To Improve the Supercapacitive Performance of Carbon Nano-onions

Recently, enhancement of the energy density of a supercapacitor is restricted by the inferior capacitance of negative electrodes, which impedes the commercial development of high-performance symmetric and asymmetric supercapacitors. This article introduces the in situ bulk-quantity synthesis of hydrophilic, porous, graphitic sulfur-doped carbon nano-onions (S-CNO) using a facile flame-pyrolysis technique and evaluated its potential applications as a high-performance supercapacitor electrode in a symmetric device configuration. The high-surface wettability in the as-prepared state enables the formation of highly suspended active conducting material S-CNO ink, which eliminates the routine use of binders for the electrode preparation. The as-prepared S-CNO displayed encouraging features for electrochemical energy storage applications with a high specific surface area (950 m² g^-1), ordered mesoporous structure (∼3.9 nm), high S-content (∼3.6 at. %), and substantial electronic conductivity, as indicated by the ∼80% sp² graphitic carbon content. The in situ sulfur incorporation into the carbon framework of the CNO resulted in a high-polarized surface with well-distributed reversible pseudosites, increasing the electrode-electrolyte interaction and improving the overall conductivity. The S-CNOs showed a specific capacitance of 305 F g^-1, an energy density of 10.6 W h kg^-1, and a power density of 1004 W kg^-1 at an applied current density of 2 A g^-1 in a symmetrical two-electrode cell configuration, which is approximately three times higher than that of the pristine CNO-based device in a similar electrochemical testing environment. Even at 11 A g^-1, the S-CNO||S-CNO device rendered an energy density (6.1 W h kg^-1) at a deliverable power density of 5.5 kW kg^-1, indicating a very good rate capability and power management during peak power delivery applications. Furthermore, it showed a high degree of electrochemical reversibility with excellent cycling stability, retaining ∼95% of its initial capacitance after more than 10 000 repetitive charge-discharge cycles at an applied current density of 5 A g^-1.

One-step nonhydrolytic sol-gel synthesis of mesoporous TiO2 phosphonate hybrid materials

Mesoporous TiO₂-octylphosphonate hybrid materials were prepared in one step by a nonhydrolytic sol-gel method involving the reaction of Ti(OiPr)₄, acetophenone (2 equiv) and diethyl octylphosphonate (from 0 to 0.2 equiv) at 200 °C for 12 hours, in toluene. The different samples were characterized by ³¹P magic angle spinning nuclear magnetic resonance, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and nitrogen physisorption. For P/Ti ratios up to 0.1, the hybrid materials can be described as aggregated, roughly spherical, crystalline anatase nanoparticles grafted by octylphosphonate groups via Ti-O-P bonds. The crystallite size decreases with the P/Ti ratio, leading to an increase of the specific surface area and a decrease of the pore size of the hybrid samples. For a P/Ti ratio of 0.2, the volume fraction of organic octyl groups exceeds 50%. The hybrid material becomes nonporous and can be described as amorphous TiO₂ clusters modified by octylphosphonate units, where the octyl chains form an organic continuous matrix.

ZnO/ZnO2/Pt Janus Micromotors Propulsion Mode Changes with Size and Interface Structure: Enhanced Nitroaromatic Explosives Degradation under Visible Light

Self-motile mesoporous ZnO/Pt-based Janus micromotors accelerated by bubble propulsion that provide efficient removal of explosives and dye pollutants via photodegradation under visible light are presented. Decomposition of H₂O₂ (the fuel) is triggered by a platinum catalytic layer asymmetrically deposited on the nanosheets of the hierarchical and mesoporous ZnO microparticles. The size-dependent motion behavior of the mesoporous micromotors is studied; the micromotors with average size ∼1.5 μm exhibit enhanced self-diffusiophoretic motion, whereas the fast bubble propulsion is detected for micromotors larger than 5 μm. The bubble-propelled mesoporous ZnO/Pt Janus micromotors show remarkable speeds of over 350 μm s^-1 at H₂O₂ concentrations lower than 5 wt %, which is unusual for Janus micromotors based on dense materials such as ZnO. This high speed is related to efficient bubble nucleation, pinning, and growth due to the highly active and rough surface area of these micromotors, whereas the ZnO/Pt particles with a smooth surface and low surface area are motionless. We discovered new atomic interfaces of ZnO₂ introduced into the ZnO/Pt micromotor system, as revealed by X-ray diffraction (XRD), which contribute to enhance their photocatalytic activity under visible light. Such coupling of the rapid movement with the high catalytic performance of ZnO/Pt Janus micromotors provides efficient removal of nitroaromatic explosives and dye pollutants from contaminated water under visible light without the need for UV irradiation. This paves the way for real-world environmental remediation efforts using microrobots.

Two-Dimensional Sandwich-Structured Mesoporous Mo2C/Carbon/Graphene Nanohybrids for Efficient Hydrogen Production Electrocatalysts

The main challenge in water electrolysis, an appealing technique to alleviate future energy crisis, is the design of efficient electrocatalysts for hydrogen evolution reaction (HER). On the basis of an interface self-assembly approach, we synthesize mesoporous nitrogen-doped carbon/Mo₂C/reduced graphene oxide nanohybrids (denoted as mNC-Mo₂C@rGO), which represent a new type of two-dimensional Mo₂C/carbon hybrid nanomaterials and possess a sandwichlike structure with well-defined mesopores. The method involves the co-self-assembly of spherical micelles formed from polystyrene- block-poly(ethylene oxide), pyrrole (Py) monomers, and molybdate ions (Mo₇O₂₄^6-) on GO surfaces in aqueous solution, followed by polymerization of Py and calcination of the nanocomposites at 900 °C under nitrogen atmosphere. The resultant mNC-Mo₂C@rGO nanosheets possess high N contents, large specific surface areas (SSAs), and 4 nm Mo₂C particles well-distributed in the mesoporous carbon matrix. The Mo₂C content is controllable in the range of 18.4-42.4 wt % by adjusting the feed amount of Mo₇O₂₄^6-. In particular, mNC-Mo₂C@rGO with an SSA of 344 m²/g and a Mo₂C content of ca. 28 wt % exhibits the highest HER catalytic activity in 1 M KOH electrolyte, with a 95 mV overpotential at 10 mA/cm², a Tafel slope of 49.8 mV/dec, and a long-term stability of 60 h at 20 mA/cm². This study blazes a trail for the synthesis of new functional nanomaterials with potential applications as efficient HER electrocatalysts.

Encapsulation of Metal Nanoparticle Catalysts Within Mesoporous Zeolites and Their Enhanced Catalytic Performances: A Review

Metal nanoparticles (NPs) exhibit desired activities in various catalytic reactions. However, the aggregation and sintering of metal NPs usually cause the loss of catalytic performance in practical reaction processes. Encapsulation of catalytically active metal NPs on/within a high-surface-area inorganic support partially resolve such concerns. Microporous zeolites, owing to their rigid frameworks and porous structural features, have been considered as one of ideal inorganic supports. Metal NPs can be easily encapsulated and stabilized within zeolitic frameworks to prevent unwished aggregation during the catalysis. Unfortunately, sole microporous nanochannels (generally <1 nm) in conventional zeolites are not easy to be accessed. The introduction of another set of nanochannel (e.g., mesopore), known as mesoporous zeolites, can greatly improve the mass-transfer efficiency, which is structurally beneficial for most catalytic reactions. The coexistence of micropores and mesopores in inorganic supports provides the synergetic advantages of both fine confinement effect for metal NPs and easy diffusion for organic reactants/intermediates/products. This review focuses on the recent advances in the design and synthesis of mesoporous zeolites-encapsulated metal NP catalysts as well as their desired catalytic performances (activity and stability) in organic reactions. We first discuss the advantages of mesoporous zeolites as the supports and present general strategies for the construction of mesoporous zeolites. Then, the preparation methods on how to encapsulate NP catalysts within both microporous and mesoporous zeolites are clearly demonstrated. Third, some recent important cases on catalytic applications are presented to verify structural advantages of mesoporous zeolite supports. Within the conclusion, the perspectives on future developments in metal NP catalysts encapsulated within mesoporous zeolites are lastly discussed.

Silk Fibroin Microparticles with Hollow Mesoporous Silica Nanocarriers Encapsulation for Abdominal Wall Repair

Therapeutic vascularization appears to be an effective way of repairing abdominal wall defects. Attempts to implement this treatment tend to focus on the generation of featured drug carriers with the ability effectively to encapsulate the angiogenesis-stimulating agents and control their release to maintain an appropriate concentration at the injured area. Here, a new type of composite microparticle (CM) composed of silk fibroin (SF) and hollow mesoporous silica nanocarriers (HMSNs) is presented for therapeutic agent delivery. The CMs are generated by drying microfluidic emulsion templates of HMSN-dispersed SF solution. The resultant CMs have a distinctive micro-nanostructure, in which two barriers control the drug release. The encapsulated HMSNs increase the drug-carrying capacity of the CMs, and also form the first barrier via physical absorption. The microfluidic SF microparticles not only provide a shell with excellent monodispersity and biocompatibility but also form the second barrier via efficient encapsulation. Because of these superior properties of the CMs, the loaded drugs can be delivered with a satisfactory activity at the required rate, making them ideal for implementing therapeutic vascularization and repairing abdominal wall defects.

Review on the Production of Polysaccharide Aerogel Particles

A detailed study of the production of polysaccharide aerogel (bio-aerogel) particles from lab to pilot scale is surveyed in this article. An introduction to various droplets techniques available in the market is given and compared with the lab scale production of droplets using pipettes and syringes. An overview of the mechanisms of gelation of polysaccharide solutions together with non-solvent induced phase separation option is then discussed in the view of making wet particles. The main steps of particle recovery and solvent exchange are briefly described in order to pass through the final drying process. Various drying processes are overviewed and the importance of supercritical drying is highlighted. In addition, we present the characterization techniques to analyse the morphology and properties of the aerogels. The case studies of bio-aerogel (agar, alginate, cellulose, chitin, κ-carrageenan, pectin and starch) particles are reviewed. Potential applications of polysaccharide aerogel particles are briefly given. Finally, the conclusions summarize the prospects of the potential scale-up methods for producing bio-aerogel particles.

Incorporating Heavy Alkanes in Metal-Organic Frameworks for Optimizing Adsorbed Natural Gas Capacity

Metal-organic frameworks (MOFs) as methane adsorbents are highly promising materials for applications such as methane-powered vehicles, flare gas capture, and field natural gas separation. Pre- and post-synthetic modification of MOFs have been known to help improve both the overall methane uptake as well as the working capacity. Here, a post-synthetic modification strategy to non-covalently modify MOF adsorbents for the enhancement of the natural gas uptake for the MOF material is introduced. In this study, PCN-250 adsorbents were doped with C₁₀ alkane and C₁₄ fatty acid and their impact on the methane uptake capabilities was investigated. It was found that even trace amounts of heavy hydrocarbons could considerably enhance the raw methane uptake of the MOF while still being regenerable. The doped hydrocarbons are presumably located at the mesoporous defects of PCN-250, thus optimizing the framework-methane interactions. These findings reveal a general approach that can be used to modify the MOF absorbents, improving their ability to be sustainable and renewable natural gas adsorption platforms.

Internal Structure of Matrix-Type Multilayer Capsules Templated on Porous Vaterite CaCO₃ Crystals as Probed by Staining with a Fluorescence Dye

Multilayer capsules templated on decomposable vaterite CaCO₃ crystals are widely used as vehicles for drug delivery. The capsule represents typically not a hollow but matrix-like structure due to polymer diffusion into the porous crystals during multilayer deposition. The capsule formation mechanism is not well-studied but its understanding is crucial to tune capsule structure for a proper drug release performance. This study proposes new approach to noninvasively probe and adjust internal capsule structure. Polymer capsules made of poly(styrene-sulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDAD) have been stained with fluorescence dye rhodamine 6G. Physical-chemical aspects of intermolecular interactions required to validate the approach and adjust capsule structure are addressed. The capsules consist of a defined shell (typically 0.5⁻2 µm) and an internal matrix of PSS-PDAD complex (typically 10⁻40% of a total capsule volume). An increase of ionic strength and polymer deposition time leads to the thickening of the capsule shell and formation of a denser internal matrix, respectively. This is explained by effects of a polymer conformation and limitations in polymer diffusion through the crystal pores. We believe that the design of the capsules with desired internal structure will allow achieving effective encapsulation and controlled/programmed release of bioactives for advanced drug delivery applications.

Mesoporous Colloidal Photonic Crystal Particles for Intelligent Drug Delivery

Particle-based delivery systems demonstrate a pregnant value in the fields of drug research and development. Efforts to advance this technology focus on the fabrication of functional particles with enhanced efficiency and performance for drug delivery. Here, we present a new type of mesoporous colloidal photonic crystal particle (MCPCP)-based drug-delivery system with distinct features. As the MCPCPs were constructed by self-assembling monodisperse mesoporous nanoparticles in microfluidic droplet templates, they were composed of hierarchical macro- and mesoporous structures and could provide plenty of nanopores and interconnected nanochannels for synergistic loading of both micro- and macromolecule drugs with large quantity and sustained release. In addition, by integrating the stimuli-responsive poly( N-isopropylacrylamide) hydrogel into the MCPCPs and employing it as a "gating" to control the opening of the macro- and mesopores, the MCPCP delivery systems were imparted with the function of controllable release. More attractively, as the average refractive index of the MCPCPs was decreased during the release of the loaded actives, the photonic band gaps of the MCPCPs blue-shifted correspondingly; this provided a novel stratagem for real-time self-reporting of the therapeutic agent release process of the MCPCPs. Hence, the MCPCPs are ideal for intelligent drug delivery because of these dramatical features.

Mesoporous Pd@Ru Core-Shell Nanorods for Hydrogen Evolution Reaction in Alkaline Solution

The activity and stability of bimetallic nanocatalysts strongly depend on their structures, compositions, and interfaces. Here, we report the synthesis of mesoporous Pd@Ru core-shell bimetallic nanorods composed of face-centered cubic Pd and hexagonal close-packed Ru. The nanorods have two types of cavities with diameters of 3.0 ± 0.9 and 20.3 ± 8.1 nm. The mutual diffusion process between Ru and Pd is characterized by the high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy mapping, and the synchrotron radiation photoemission spectroscopy measurements. The mesoporous Pd@Ru nanorods exhibit superior catalytic performance and stability for hydrogen evolution reactions (overpotentials of 30 mV at 10 mA·cm^-2 in 1.0 M KOH solution and 37 mV at 10 mA·cm^-2 in 0.5 M H₂SO₄ solution).

Hydrogels as Porogens for Nanoporous Inorganic Materials

Organic polymer-hydrogels are known to be capable of directing the nucleation and growth of inorganic materials, such as silica, metal oxides, apatite or metal chalcogenides. This approach can be exploited in the synthesis of materials that exhibit defined nanoporosity. When the organic polymer-based hydrogel is incorporated in the inorganic product, a composite is formed from which the organic component may be selectively removed, yielding nanopores in the inorganic product. Such porogenic impact resembles the concept of using soft or hard templates for porous materials. This micro-review provides a survey of select examples from the literature.

Au-TiO2-Loaded Cubic g-C3N4 Nanohybrids for Photocatalytic and Volatile Organic Amine Sensing Applications

A green and efficient approach for efficient nanohybrid photocatalysts in extending the light response to the visible spectrum is a hot research topic in sustainable energy technologies. In this work, novel Au-TiO₂@m-CN nanocomposite was synthesized using hard template of cubic ordered mesoporous KIT-6 via the nanocasting process. The as-prepared Au-TiO₂@m-CN nanohybrids exhibit enhanced photocatalytic activities with improved stability and reusability using methyl orange dye. The enhanced photocatalytic performance is a result of the conjugated effect of catalytic active Au and TiO₂ nanoparticles supported on highly efficient visible light sensitizer, graphitic carbon nitride (m-CN or g-C₃N₄), and ordered mesoporous morphology. Besides, the sensing performance of Au-TiO₂@m-CN nanohybrids was also tested for the detection of amine gases, wherein a significant response was reported for triethylamine at low operating temperatures. This study reveals a simple and scalable methodology to design and develop next generation of layered mesoporous materials for multifunctional applications.

Fabrication and Characterization of Strontium-Substituted Hydroxyapatite-CaO-CaCO₃ Nanofibers with a Mesoporous Structure as Drug Delivery Carriers

Hydroxyapatite (HAp) is the main inorganic component and an essential part of hard bone and teeth. Due to its excellent biocompatibility, bioactivity, and osteoconductivity, synthetic HAp has been widely used as a bone substitute, cell carrier, and therapeutic gene or drug carrier. Recently, numerous studies have demonstrated that strontium-substituted hydroxyapatite (SrHAp) not only enhances osteogenesis but also inhibits adipogenesis in mesenchymal stem cells. Mesoporous SrHAp has been successfully synthesized via a traditional template-based process and has been found to possess better drug loading and release efficiencies than SrHAp. In this study, strontium-substituted hydroxyapatite-CaO-CaCO₃ nanofibers with a mesoporous structure (mSrHANFs) were fabricated using a sol⁻gel method followed by electrospinning. X-ray diffraction analysis revealed that the contents of CaO and CaCO₃ in the mSrHANFs decreased as the doping amount of Sr increased. Scanning electron microscopy (SEM) images showed that the average diameter of the mSrHANFs was approximately 200~300 nm. The N₂ adsorption⁻desorption isotherms demonstrated that the mSrHANFs possessed a mesoporous structure and that the average pore size was approximately 20~25 nm. Moreover, the mSrHANFs had excellent drug- loading efficiency and could retard the burst release of tetracycline (TC) to maintain antibacterial activity for over 3 weeks. Hence, mSrHANFs have the potential to be used as drug carriers in bone tissue engineering.

Mesoporous ZnMn2O4 Microtubules Derived from a Biomorphic Strategy for High-Performance Lithium/Sodium Ion Batteries

ZnMn₂O₄ microtubules (ZMO-MTs) with a mesoporous structure are fabricated by a novel yet effective biomorphic approach employing cotton fiber as a biotemplate. The fabricated ZMO-MT has approximately an inner diameter of 8.5 μm and wall thickness of 1.5 μm. Further, the sample of ZMO-MT displays a large specific surface area of 48.5 m² g^-1. When evaluated as a negative material for Li-ion batteries, ZMO-MT demonstrates an improved cyclic performance with discharge capacities of 750.4 and 535.2 mA h g^-1 after 300 cycles, under current densities of 200 and 500 mA g^-1, respectively. Meanwhile, ZMO-MT exhibits superior rate performances with high reversible discharge capacities of 614.7 and 465.2 mA h g^-1 under high rates of 1000 and 2000 mA g^-1, respectively. In sodium ion batteries applications, ZMO-MT delivers excellent high discharge capacities of 102 and 71.4 mA h g^-1 after 300 cycles under 100 and 200 mA g^-1, respectively. An excellent rate capability of 58.2 mA h g^-1 under the current density of 2000 mA g^-1 can also be achieved. The promising cycling performance and rate capability could be benefited from the unique one-dimensional mesoporous microtubular architecture of ZMO-MT, which offers a large electrolyte/electrode accessible contact area and short diffusion distance for both of ions and electrons, buffering the volume variation originated from the repeated ion intercalation/deintercalation processes.

A Modified In Situ Method to Determine Release from a Complex Drug Carrier in Particle-Rich Suspensions

Effective and compound-sparing methods to evaluate promising drug delivery systems are a prerequisite for successful selection of formulations in early development stages. The aim of the study was to develop a small-scale in situ method to determine drug release and supersaturation in highly concentrated suspensions of enabling formulations. Mesoporous magnesium carbonate (MMC), which delivers the drug in an amorphous form, was selected as a drug carrier. Five model compounds were loaded into the MMC at a 1:10 ratio using a solvent evaporation technique. The μDiss Profiler was used to study the drug release from MMC in fasted-state simulated intestinal fluid. To avoid extensive light scattering previously seen in particle-rich suspensions in the μDiss Profiler, an in-house-designed protective nylon filter was placed on the in situ UV probes. Three types of release experiments were conducted for each compound: micronized crystalline drug with MMC present, drug-loaded MMC, and drug-loaded MMC with 0.01% w/w hydroxypropyl methyl cellulose. The nylon filters effectively diminished interference with the UV absorption; however, the release profiles obtained were heavily compound dependent. For one of the compounds, changes in the UV spectra were detected during the release from the MMC, and these were consistent with degradation of the compound. To conclude, the addition of protective nylon filters to the probes of the μDiss Profiler is a useful contribution to the method, making evaluations of particle-rich suspensions feasible. The method is a valuable addition to the current ones, allowing for fast and effective evaluation of advanced drug delivery systems.

Production and Physicochemical Characterization of Cu-Doped Silicate Bioceramic Scaffolds

Development of ion-releasing implantable biomaterials is a valuable approach for advanced medical therapies. In the effort of tackling this challenge, we explored the feasibility of porous bioceramic scaffolds releasing copper ions, which are potentially able to elicit angiogenetic and antibacterial effects. First, small amounts of CuO were incorporated in the base silicate glass during melting and the obtained powders were further processed to fabricate glass–ceramic scaffolds by sponge replica method followed by sinter crystallization. As the release of copper ions from these foams in simulated body fluid (SBF) was very limited, a second processing strategy was developed. Silicate glass–ceramic scaffolds were coated with a layer of Cu-doped mesoporous glass, which exhibited favorable textural properties (ultrahigh specific surface area >200 m²/g, mesopore size about 5 nm) for modulating the release of copper. All the produced scaffolds, containing biocompatible crystals of wollastonite (CaSiO₃), revealed high stability in a biological environment. Furthermore, the materials had adequate compressive strength (>10 MPa) for allowing safe manipulation during surgery. Overall, the results achieved in the present work suggest that these Cu-doped glass-derived scaffolds show promise for biomedical application and motivate further investigation of their suitability from a biological viewpoint.

Supersaturation Potential of Ordered Mesoporous Silica Delivery Systems. Part 1: Dissolution Performance and Drug Membrane Transport Rates

Ordered mesoporous silica materials have shown great potential as oral drug delivery systems for poorly soluble drugs. However, the ability of these delivery systems to generate drug supersaturation has not been widely investigated, and the recently noted phenomenon of incomplete drug release is not well understood. Therefore, the aim of this study was to comprehensively evaluate the release of hydrophobic drug molecules into solution from ordered mesoporous silica, focusing on the extent and duration of drug supersaturation. The dissolution and supersaturation behavior of ritonavir, following loading into mesoporous SBA-15 silica particles, was investigated by undertaking simple in vitro dissolution studies in phosphate buffer pH 6.8 and fasted state simulated intestinal fluid, as well as membrane flux studies using a side-by-side diffusion cell apparatus. It was found that supersaturated ritonavir solutions were generated from ritonavir-loaded mesoporous SBA-15 particles; however, drug release was always incomplete, even under sink conditions. In addition, the percentage drug release was observed to decrease significantly as the theoretical supersaturation ratio and dose of ritonavir-loaded SBA-15 formulation increased. The data obtained suggest an equilibrium exists between drug adsorbed to the SBA-15 silica surface and free drug present in solution. The findings described herein are highly significant in aiding our understanding of ordered mesoporous silica as a supersaturating drug delivery system for bioavailability enhancement.

Tunable Silver-Functionalized Porous Frameworks for Antibacterial Applications

Healthcare-associated infections and the rise of drug-resistant bacteria pose significant challenges to existing antibiotic therapies. Silver nanocomposites are a promising solution to the current crisis, however their therapeutic application requires improved understanding of underpinning structure-function relationships. A family of chemically and structurally modified mesoporous SBA-15 silicas were synthesized as porous host matrices to tune the physicochemical properties of silver nanoparticles. Physicochemical characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES) and porosimetry demonstrate that functionalization by a titania monolayer and the incorporation of macroporosity both increase silver nanoparticle dispersion throughout the silica matrix, thereby promoting Ag₂CO₃ formation and the release of ionic silver in simulated tissue fluid. The Ag₂CO₃ concentration within functionalized porous architectures is a strong predictor for antibacterial efficacy against a broad spectrum of pathogens, including C. difficile and methicillin-resistant Staphylococcus aureus (MRSA).