Well-ordered Mesoporous Structure Research Articles

Enhancing Osteoblastic Cell Cultures with Gelatin Methacryloyl, Bovine Lactoferrin, and Bioactive Mesoporous Glass Scaffolds Loaded with Distinct Parsley Extracts.

The increasing interest in innovative solutions for addressing bone defects has driven research into the use of Bioactive Mesoporous Glasses (MBGs). These materials, distinguished by their well-ordered mesoporous structure, possess the capability to accommodate plant extracts with well-established osteogenic properties, including bovine lactoferrin (bLF), as part of their 3D scaffold composition. This harmonizes seamlessly with the ongoing advancements in the field of biomedicine. In this study, we fabricated 3D scaffolds utilizing MBGs loaded with extracts from parsley leaves (PL) and embryogenic cultures (EC), rich in bioactive compounds such as apigenin and kaempferol, which hold potential benefits for bone metabolism. Gelatin Methacryloyl (GelMa) served as the polymer, and bLF was included in the formulation. Cytocompatibility, Runx2 gene expression, ALP enzyme activity, and biomineralization were assessed in preosteoblastic MC3T3-E1 cell cultures. MBGs effectively integrated PL and EC extracts with loadings between 22.6 ± 0.1 and 43.6 ± 0.3 µM for PL and 26.3 ± 0.3 and 46.8 ± 0.4 µM for EC, ensuring cell viability through a release percentage between 28.3% and 59.9%. The incorporation of bLF in the 3D scaffold formulation showed significant differences compared to the control in all assays, even at concentrations below 0.2 µM. Combinations, especially PL + bLF at 0.19 µM, demonstrated additive potential, with superior biomineralization compared to EC. In summary, this study highlights the effectiveness of MBGs in incorporating PL and EC extracts, along with bLF, into 3D scaffolds. The results underscore cytocompatibility, osteogenic activity, and biomineralization, offering exciting potential for future in vivo applications.

Synergistic mesoporous bimetallic gold-silver nanoparticles: Synthesis, structure, and superior electrocatalytic activity

Mesoporous bimetallic nanoparticles have gained immense interest due to their unique properties and applications in various fields. In this study, we report a novel and straightforward one-pot chemical reduction method for the synthesis of mesoporous AuAg nanoparticles, featuring a substantial mesopore size (>10 nm) and a well-defined structure. The synthetic route involves employing L-cysteine as a ligand to form thiolate-metal(I) complexes and co-reduction of metal precursors around sacrificial templates of polymeric micelles. The resulting nanoparticles exhibit remarkable uniformity in size and possess a well-ordered mesoporous structure. Structural analyses confirm the formation of an alloy system containing Au and Ag without any distinct phases. By adjusting the initial precursor composition, precise control over the Au:Ag ratios in the final products is achievable. The electrocatalytic activity of mesoporous AuAg nanoparticles in the electrooxidation of small molecules surpasses that of mesoporous Au nanoparticles, owing to the synergistic effect arising from both the alterations in the electronic structure and the benefits offered by the porous architecture. This synthetic approach provides a promising avenue for developing efficient and cost-effective mesoporous Au-based nanoparticles for a diverse range of applications.

Ultrafast removal of antibiotic linezolid under visible light irradiation with a novel Au nanoparticles dispersed polypyrrole-carbon black/ZnTiO3 photocatalyst

Surface modification and bandgap engineering of ZnTiO3 could be highly significant towards the enhancement of its photocatalytic performance by suppressing the recombination rate of charge carriers. In this report, we developed a novel ternary photocatalyst comprised of ZnTiO3 nanostructures, polypyrrole doped carbon back (PPy-C) and gold nanoparticles (Au NPs). ZnTiO3 nanostructures were prepared by a modified sol–gel process. PPy-C and Au NPs associated ZnTiO3 ternary photocatalyst (Au@PPy-C/ZnTiO3) was effectively developed by ultra-sonication approach followed by a photo-reduction methodology. XRD analysis confirmed the existence of rhombohedral ZnTiO3 in ternary nanocomposite with perfect dispersion of Au NPs on PPy-C/ZnTiO3 hybrid structure. The formation of this Au@PPy-C/ZnTiO3 photocatalyst was further confirmed by XPS and EDS investigation. FTIR investigation also confirmed the trio photocatalytic structure among Au NPs, PPy-C and ZnTiO3. Synthesized Au@PPy-C/ZnTiO3 photocatalyst was found to be highly effectual and ultrafast under visible light illumination with 92.70 % removal of target linezolid molecule (an antibiotic drug) just in 20 min, almost 1.95 times (195 %) more efficacious than bare ZnTiO3. Additionally, the newly synthesized ternary photocatalyst completely removed methylene blue (MB) dye just in 15 min when exposed to visible light. These ultrafast degradation skills of Au@PPy-C/ZnTiO3 were attributed to well-ordered mesoporous structure with high surface area, favorable bandgap, enhancement in visible light absorption and effective decline in recombination rate of photogenerated charge carriers.

Catalytic Ozonation of Atrazine Enhanced by Mesoporous CeO2: Morphology, Performance and Intermediates

Heterogeneous catalytic ozonation is an alternative approach for the removal of refractory pollutants from water, and the fabrication of mesoporous materials with high dispersibility would enhance the catalytic efficiency. A mesoporous CeO2 was prepared by the nanocasting method with SBA-15 as a hard template, and was investigated in the catalytic ozonation of atrazine. The synthetical CeO2 nanorods have a specific surface area of 95.08 m2/g, a diameter of 10.16 nm, and a spacing of 2.18 nm. The removal rate of atrazine was 85.5%, 64.8%, and 46.4% in the order of catalytic ozonation by synthetical CeO2 > single ozonation > catalytic ozonation by commercial CeO2, respectively. The superior activity of the synthetical CeO2 could be attributed to the well-ordered mesoporous structure, the high surface area, and the redox Ce3+/Ce4+ cycling. Moreover, eight organic intermediates were identified after one minute of catalytic ozonation of atrazine, and the cleavage of the ethylamino group was proposed as the main pathway of atrazine degradation.

Ordered Mesoporous Silica Prepared in Different Solvent Conditions: Application for Cu(II) and Pb(II) Adsorption.

In this work, the synthesis of ordered mesoporous silica of MCM-41 type was investigated aimed at improving its morphology by varying the synthesis conditions in a one-pot process, employing different temperatures and solvent conditions. 2-methoxyethanol was used as co-solvent to ethanol. The co-solvent ratio and the synthesis temperature were varied. The pore morphology of the materials was characterized by nitrogen porosimetry and small angle neutron scattering (SANS), and the particle morphology by transmission electron microscopy (TEM) and ultra-small angle neutron scattering (USANS). The thermal behavior was investigated by simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) measurements. The SANS and N2 sorption results demonstrated that a well-ordered mesoporous structure was obtained at all conditions in the synthesis at room temperature. Addition of methoxyethanol led to an increase of the pore wall thickness. Simultaneously, an increase of methoxyethanol content led to lowering of the mean particle size from 300 to 230 nm, according to the ultra-small angle scattering data. The ordered porosity and high specific surfaces make these materials suitable for applications such as adsorbents in environmental remediation. Batch adsorption measurements of metal ion removal from aqueous solutions of Cu(II) and Pb(II) showed that the materials exhibit dominantly monolayer surface adsorption characteristics. The adsorption capacities were 9.7 mg/g for Cu(II) and 18.8 mg/g for Pb(II) at pH 5, making these materials competitive in performance to various composite materials.

Amphiphilic-triblock-copolymer-derived protective layer for stable-cycling lithium metal anodes

Lithium metal batteries have shown great potential for the development of efficient energy storage devices. However, the uncontrollable growth of lithium metal dendrites results in poor cycling efficiency and severe safety concerns. In this study, amphiphilic triblock copolymers (P123) were used for the direct polymerization of silica precursors, resulting in a well-ordered mesoporous silica structure SBA-15 with a large surface area and excellent absorbent properties for the protective layer. The protective layer consisting of SBA-15 stores Li ions in a large number of pores as an electrolyte reservoir, which exhibits sufficient ionic conductivity. Furthermore, it ensures a spatially uniform Li-ion flux on the anode surface and plays an important role in the physical blocking of dendrite growth. As proof of concept, the SAB-15 protective layer anode demonstrates a high average Coulomb efficiency, rate capability, and cycle stability at 1 mA h cm−2 over 1200 cycles. Moreover, SAB-15 can be cycled stably for more than 750 cycles in symmetric cells. The results provide insights for implementing stable lithium metal anodes in next-generation batteries.

Egg-yolk core-shell mesoporous silica nanoparticles for high doxorubicin loading and delivery to prostate cancer cells.

Mesoporous silica-based nanoparticles (MSNs) have gained rapid interest as a drug delivery system (DDS) and demonstrated their versatility in delivering drugs for the treatment of various cancers. However, the drug loading efficiency of MSNs is low and is usually improved by improving textural properties through complicated synthesis methods or by post synthesis modification of the surface that can result in the loss of surface area and modify its drug release properties. In this study, we report a direct single-step synthesis of MSNs with a unique egg-yolk core-shell morphology, large pore volume and a hydrophilic surface, decorated with nitrogen rich surface functionalities for increasing its drug loading capacity. This combination of excellent textural properties and surface functionalisation was achieved by a simple soft templating method using dual surfactants and the silica sources assisted by employing either triethylamine (TEA) or triethanolamine (TEO) as the hydrolysis agent. The morphology and well-ordered mesoporous structure can simply be tuned by changing the pH of the synthesis medium that affects the self-assembly mechanism of the micelles. HRTEM image of samples clearly revealed an egg-yolk core-shell morphology with a thin mesoporous silica shell. The optimised MSN samples synthesized at a pH of 11 using either TEA or TEO depicted a higher doxorubicin (Dox) loading capacity of 425 μg mg-1 and 481 μg mg-1 respectively, as compared to only 347 μg mg-1 for MSN samples due to the uniform distribution of nitrogen functionalities. The anticancer activity of Dox loaded MSNs evaluated in two different prostate cancer cell lines (PC-3 and LNCaP) showed a higher cytotoxicity of the drug loaded on optimised MSN samples as compared to pristine MSNs without affecting the cellular uptake of the particles. These results suggest that the unique single-step synthesis and functionalisation method resulted in successfully achieving higher drug loading in egg-yolk core-shell nitrogen functionalised MSNs and could be implemented as an effective carrier of chemotherapeutic drugs.

Synthesis of MgO-doped ordered mesoporous carbons by Mg2+-tannin coordination for efficient isomerization of glucose to fructose

In-situ MgO-doped ordered mesoporous carbon (OMC@MgO) was fabricated by formaldehyde-free self-assembly method, in which biomass-derived tannin was used as carbon precursor replacing fossil-based phenolics, Mg2+ as both cross-linker and precursor of catalytic sites. Up to ∼20 wt% MgO could be doped in the carbon skeleton with good dispersion retaining well-ordered mesoporous structures, while more MgO content (35 wt%) led to the failing in the formation of ordered mesoporous structure. The OMC@MgO possessed a high specific surface area (298.8 m2 g−1), uniform pore size distribution (4.8 nm) and small crystallite size of MgO (1.73 nm) due to the confinement effect of ordered mesoporous structure. Using OMC@MgO as the heterogeneous catalyst, a maximum fructose yield of 32.4% with a selectivity up to 81.1% was achieved from glucose in water (90 °C, 60 min), which is much higher than that obtained using the MgO doped active carbon via conventional post-impregnation method (26.5% yield with 58.3% selectivity). Higher reaction temperature (>90 °C) resulted in decrease of selectivity due to the formation of humins. The designed OMC@MgO displayed tolerant to high initial glucose concentrations (10 wt%) and could remain good recyclability without significant loss of activity for three cycles.

A Facile Route to Synthesis of Hierarchically Porous Carbon via Micelle System for Bifunctional Electrochemical Application.

Well-ordered hierarchically porous carbon (HPC) nanomaterials have been successfully synthesized by a facile, efficient, and fast heated-evaporation induced self-assembly (HISA) method. A micelle system was employed as the template by using the HISA method for the first time, which possessed great potential in the large-scale production of HPC materials. Various surfactants, including triblock copolymer Pluronic F127, P123, F108, and cationic CTAB, were used in the polymerization process as templates to reveal the relationship between the structure of surfactants and architecture of the as-prepared HPCs. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Nitrogen adsorption, and Fourier transform infrared (FTIR) measurements were conducted to investigate the morphology, structure, and components of HPCs, which further confirmed the well-ordered and uniform mesoporous structure. The as-prepared HPC sample with F127 possessed the largest specific surface area, suitable pore size, and well-ordered mesoporous structure, resulting in better electrochemical performance as electrodes in the fields of energy storage and conversion system. Doped with the metallic oxide MnO2, the MnO2/HPC composites presented the outstanding electrochemical activity in supercapacitor with a high specific capacitance of 531.2 F g−1 at 1 A g−1 and excellent cycling performance with little capacity fading, even after 5,000 cycles. Moreover, the obtained sample could also be applied in the fields of oxygen reduction reaction (ORR) for its abundant active sites and regulate architecture. This versatile approach makes the mass industrial production of HPC materials possible in electrochemical applications through a facile and fast route.

An injectable mesoporous silica-based analgesic delivery system prolongs the duration of sciatic nerve block in mice with minimal toxicity

The major limitation of traditional local anesthetics is the finite duration of a single injection. The present study developed two kinds of novel injectable anesthetic nanocomposites based on mesoporous silica, and evaluated their long-lasting analgesic effect and biosafety. The nanoparticulate carriers, mesoporous silica nanoparticles (MSNs) and mesoporous silica-coated gold nanorods (GNR@MSN), were firstly constructed using the oil-water biphase reaction approach and then ropivacaine (RPC), a local anesthetic, was loaded into the mesoporous carriers by vacuum suction. Transmission electron microscopic images showed the well-ordered mesoporous structure for drug loading. RPC-loaded MSNs and RPC-loaded GNR@MSN exhibited a sustained-release pattern in vitro, and the latter also showed a controlled-release manner triggered by near-infrared (NIR) irradiation. RPC-loaded MSNs and RPC-loaded GNR@MSN caused an initial sensory blockade in mice that lasted for 6 h, almost 2.5 folds of that from free RPC solution. Furthermore, upon NIR irradiation, the latter induced three additional periods of the blockade. Neither of them showed motor nerve block, which may be due to the sustained release manner. The low myotoxicity and low neurotoxicity of the two nanocomposites were presented both in vitro and in vivo. These results demonstrate the potential of the mesoporous silica-based analgesic nanocomposites in effectively controlling postoperative pain, maybe RPC-loaded MSNs for moderate pain and RPC-loaded GNR@MSN for severe pain. Statement of significanceAdequate postoperative analgesia helps early functional exercise after surgery and accelerates rapid recovery, while uncontrolled postoperative pain probably develops chronic post-surgical pain that impacts the life quality of patients for a long time. However, postoperative pain management is still a challenge. The current treatment drugs are always accompanied by some side effects due to their systemic effect. Opioids have risks of addiction and respiratory depression, and nonsteroidal anti-inflammatory drugs can lead to gastrointestinal reaction. Therefore, the long-lasting local anesthetic formulation with good biocompatibility is the most promising solution to manage post-surgical pain. The present study developed novel injectable anesthetic nanocomposites based on mesoporous silica, providing long-lasting pain relief in mice with minimal toxicity.

PH and GSH dual-responsive fluorescent nanoparticles from polydopamine coating mesoporous silica for controlled drug release and real-time detection

pH and GSH dual-responsive nanoparticles with fluorescence detection were successfully prepared from the polydopamine coating on the surface of mesoporous silica via disulfide bonds (MSN-SS-PDA). The average diameter of nanoparticles was about 80–100 nm with a well-ordered mesoporous structure. The outer layer of PDA was about 10.0 nm acting as a pH and GSH sensitive gatekeeper to control drug release. Doxorubicin (DOX) was loaded into mesoporous channels to evaluate the drug loading capacity and controlled release performance. TPE-4OH, an aggregation-induced emission (AIE) luminescence, was adhered to the surface of PDA for detection of drug release in real-time. The drug release from MSN-SS-PDA nanoparticles was enhanced under acidic solutions or high GSH concentrations. The fluorescence intensity decreased gradually with the drug release, which can be used for monitoring of release process. Besides, the nanoparticles exhibited good photothermal conversion capability due to the PDA layer under near-infrared light irradiation at 808 nm. These nanoparticles present a promising future for combination therapy and real-time tracking of the release process.

Ordered Mesoporous Alumina with Tunable Morphologies and Pore Sizes for CO2 Capture and Dye Separation.

We describe a versatile and scalable strategy toward long-range and periodically ordered mesoporous alumina (Al2O3) structures by evaporation-induced self-assembly of a structure-directing ABA triblock copolymer (F127) mixed with aluminum tri-sec-butoxide-derived sol additive. We found that the separate preparation of the alkoxide sol-gel reaction before mixing with the block copolymer enabled access to a relatively unexplored parameter space of copolymer-to-additive composition, acid-to-metal molar ratio, and solvent, yielding ordered mesophases of two-dimensional (2D) lamellar, hexagonal cylinder, and 3D cage-like cubic lattices, as well as multiscale hierarchical ordered structures from spinodal decomposition-induced macro- and mesophase separation. Thermal annealing in air at 900 °C yielded well-ordered mesoporous crystalline γ-Al2O3 structures and hierarchically porous γ-Al2O3 with 3D interconnected macroscale and ordered mesoscale pore networks. The ordered Al2O3 structures exhibited tunable pore sizes in three different length scales, <2 nm (micropore), 2-11 nm (mesopore), and 1-5 μm (macropore), as well as high surface areas and pore volumes of up to 305 m2/g and 0.33 cm3/g, respectively. Moreover, the resultant mesoporous Al2O3 demonstrated enhanced adsorption capacities of carbon dioxide and Congo red dye. Such hierarchically ordered mesoporous Al2O3 are well-suited for green environmental solutions and urban sustainability applications, for example, high-temperature solid adsorbents and catalyst supports for carbon dioxide sequestration, fuel cells, and wastewater separation treatments.

Application of vanadyl hydrogen phosphate/KIT-6 composites as a catalyst for dehydration of sucrose

In this research work, the synthesis of well-ordered mesoporous structure KIT-6 silica-supported vanadyl hydrogen phosphate hemihydrate (VHP/KIT-6) catalysts possessing varying surface area was carried out, followed by being utilized in the dehydration of sucrose to 5-hydroxymethylfurfural (5-HMF) as a solid acid catalyst. The fabrication of two different VHP/KIT-6 catalysts was conducted using the impregnation approach through V2O5 reduction in alcoholic media. Then, the catalytic behavior presented by the prepared VHP/KIT-6 samples was compared with unsupported VHP and unsupported vanadyl pyrophosphate (VPP), which was prepared through the calcination of VHP precursor at 400 °C for 24 h. The prepared catalysts were characterized by different analyses, including ICP-OES, BET, XRD, NH3-TPD analysis, FT-IR spectroscopy, as well as SEM and TEM techniques. Furthermore, important parameters, including the catalyst type and weight, sucrose amount, time, temperature, and the type of solvent on sucrose dehydration, were also studied. It was observed that the highest catalytic activity in the dehydration reaction (5-HMF yield: 67%, sucrose conversion: > 94%) could be provided by the catalyst possessing the highest surface area. Moreover, the catalyst reusability was examined for consecutive four times, based on which no considerable change in the catalytic activity was observed.

Silica-Modified Ordered Mesoporous Carbon for Optimized Impedance-Matching Characteristic Enabling Lightweight and Effective Microwave Absorbers.

Ordered mesoporous carbon (OMC) is considered to be a prospective carbon-based material for microwave absorption because of its abundant well-ordered mesoporous structures, high specific surface area, numerous active sites, and facile preparation process. However, its development has been seriously hindered by its poor impedance-matching characteristic. Herein, silica-modified OMC composites with a designable impedance-matching transition layer are successfully fabricated via a self-assembly method and succeeding calcination treatment. In addition, the silica in OMC@SiO2 composites can maintain the mesoporous structure, which facilitates the scattering and reflection of microwaves in the tunnel structure. The as-prepared sample OMC-5@SiO2 exhibits a minimum reflection loss (RL) value of -40.7 dB at 10.8 GHz with 2 mm and an effective absorption bandwidth (RL ≤ -10 dB) of 4.8 GHz with a thinner absorber thickness of 1.5 mm. We believe that the as-prepared OMC@SiO2 composites can be prospective candidates as high-efficiency and lightweight microwave absorbers.

Polymer-modified mesoporous silica microcubes (P@MSMCs) for the synergistic oxidative entrapment of Ag(i), Ti(iv), and Zn(ii) from natural river water.

Herein, we demonstrate a hydrothermal route to the one-pot synthesis of polymeric mesoporous silica microcubes (P@MSMCs) for the adsorption of heavy metal ions. During the synthesis of P@MSMCs from column silica gel, the roles and combination of the polymer and an etchant were characterized. Moreover, the porosity of P@MSMCs was tailored by adjusting the reaction temperature between 75 °C and 200 °C. The characterization through UV, FTIR, FESEM, XRD, BET, and EDX techniques exhibited that P@MSMCs have a well-ordered mesoporous structure with cubic morphology. The P@MSMCs had a diameter of 2 μm, with an average pore volume and pore size of 0.69 cm3 g-1 and 10.08 nm, respectively. The results indicated that the P@MSMCs have excellent adsorption capacity for Ag(i), Ti(iv), and Zn(ii) due to the formation of an aggregated complex. These aggregations led to affordable density difference-based separation of these metal ions through centrifugation, filtration or simple decantation. The removal efficiencies for Ag(i), Ti(iv), and Zn(ii) were observed to be 520, 720, and 850 mg g-1, respectively. The kinetic studies demonstrated that the adsorption performance fitted well to the pseudo-second-order kinetic model. The as-synthesized P@MSMCs were stable in the wide pH range of 4-8. Significantly, the recycling or reuse results displayed effective adsorption performance of these P@MSMCs for up to 5 cycles. The adsorption results obtained herein will promote the development of similar strategies for the removal of heavy metal ions from natural water.

Synthesis of PLA/SBA-15 Composite Scaffolds for Bone Tissue Engineering

Composite materials are used in bone tissue engineering because they mimic the structure of the extracellular matrix of bone. In this work, polylactic acid (PLA) fiber scaffolds prepared by air-jet spinning technique, were doped with different concentrations of SBA-15 ceramic (0.05, 0.1, and 0.15 wt%). The SBA-15 ceramic powder was made by the Sol-Gel process. Physicochemical characterization of PLA, SBA-15, and composite fiber scaffold was done by XRD, SEM, BET, FTIR, TGA, mechanical test, and biocompatibility assay, which were performed in a cell culture model with osteoblast cells. Our results showed a random nanofibers composite scaffold with an improvement in the physicochemical properties. The PLA fiber diameter increases as increases the content of SBA-15, and the mechanical properties were dose-dependent. SBA-15 shows the well-ordered mesoporous hexagonal structure with a pore size of 5.8 ± 0.2 nm and a specific surface area with a value of 1042 ± 89 m2/g. PLAfibers and composites have thermal stability up to 300°C, and thermal decomposition in the range 316-367°C. In vitro biocompatibility results showed that PLA/SBA-15 composite scaffold had no cytotoxicity effect in terms of cell adhesion and viability of osteoblast cells. Furthermore, the doped SBA-15 with 0.05% wt onto the polymer matrix could be useful in biomedical applications for bone tissue engineering.

Temperature and H2O2-operated nano-valves on mesoporous silica nanoparticles for controlled drug release and kinetics

Temperature and H2O2 dual-responsive nanoparticles were fabricated from ferrocene modified mesoporous silica (MSN-Fc) and β-cyclodextrin-poly(N-isopropylacrylamide) (β-CD-PNIPAM) star-shaped polymer due to the host–guest interactions for controlled drug release. The formation and structure of β-CD-PNIPAM@MSN-Fc composite nanoparticles was confirmed by FTIR, TGA, TEM and N2 adsorption-desorption isotherms. The size of nanoparticles was about 100−150 nm with well-ordered mesoporous structure and PNIPAM chains coating on the surface as outer shell. The channels of MSNs and hydrophobic cavities of β-CD were all contributed to the high drug loading capacity for nanoparticles. The release of DOX from nanoparticles was enhanced with the increase of temperature above LCST or adding H2O2 in ambient O2. The release kinetics were studied using different models to explain drug release mechanism. Furthermore, the drug loaded composite nanoparticles exhibited excellent anti-cancer activity.

Dual-responsive nanocarriers from star shaped poly(N-isopropylacrylamide) coated mesoporous silica for drug delivery

The pH and temperature dual-responsive nanocarriers were fabricated from 2-mercaptobenzimidazole modified mesoporous silica nanoparticles (MSN-BM) and poly(N-isopropylacrylamide) star polymer based on β-cyclodextrin core（β-CD-(PNIPAM)7）coated as nanovalve by host-guest recognition. Nanoparticles show a well-ordered mesoporous structure with the pore diameter of 2–3 nm and size was about 100–150 nm. Doxorubicin (DOX) was effectively encapsulated in MSNs with the drug-loading content and entrapment efficiency up to 40.51 and 85.11%, respectively. The opening of the pores could be switched on and off by the stimulating factors, such as acid and temperature as desired. The higher the concentration of acid, the more of DOX was released from nanoparticles. Furthermore, the release of DOX from composite nanoparticles was enhanced with the temperature increased from 25 to 42 °C.

CO2-induced architectural transition of hierarchically porous carbon in reverse microemulsion system

A novel approach is provided to control the morphology and the structure of hierarchically porous carbon (HPC) materials with well-ordered mesoporous structure. A water-in-oil reverse microemulsion (F127/MMA) was employed as the reactive system and resorcinol and p-phthalaldehyde as the reactant with one-pot method by using compressed CO2. Specially, the morphology of the as-made HPC can be transformed from nanosphere to 3D network by simply increasing the pressure of CO2. Meanwhile, the porous structure of the obtained sample can be turned from mesopores/micropores to macropores/mesopores/micropores. The obtained HPC exhibits excellent performance in the CO2 adsorption, drug delivery, and supercapacitor electrode. Furthermore, the mechanism of the transformation of HPC was discussed via investigating the solution. The results imply that CO2 plays a decisive role to change the state of solution from the reserve microemulsion to Winsor type I microemulsion, leading to morphological and porous structural transformation of the as-prepared HPC. Different from conventional acid/base or inorganic additives as catalyst, CO2 can not only be employed as an acid catalyst in the crosslinking of the precursors, but also be a controller of the structure transformation of HPC. This strategy can provide a novel route to develop architectural design of HPC in green processes.

Bioactive glass nanotube scaffold with well-ordered mesoporous structure for improved bioactivity and controlled drug delivery

In this study, a novel mesoporous bioactive glass nanotube (MBGN) scaffold has been fabricated via template-assisted sol-gel method using bacterial cellulose (BC) as template and nonionic block copolymer (P123) as pore-directing agent. The scaffold was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and N2 adsorption-desorption analysis. Furthermore, simvastatin was used to evaluate the loading efficiency and release kinetics of the scaffold. The obtained scaffold displays nanofiber-like morphology, ordered mesopores on the tube walls, and interconnected three-dimensional (3D) network structure that completely replicates the BC template. In addition, it shows dual pore sizes (16.2 and 3.3 nm), large specific surface area (537.2 m2 g−1) and pore volume (1.429 cm3 g−1). More importantly, the scaffold possesses excellent apatite-forming ability and sustainable drug release as compared to the counterpart scaffold without mesopores. This unique scaffold can be considered a promising candidate for drug delivery and bone tissue regeneration.