Solid Template Research Articles

Berberine-loaded liposomes for oral delivery: Preparation, physicochemical characterization and in-vivo evaluation in an endogenous hyperlipidemic animal model

Berberine (BBR) is a plant-origin quaternary isoquinoline alkaloid presenting exogenous cholesterol lowering and anti-hyperlipidemia therapeutic effects. The aim of this study was to design and generate BBR-loaded proliposomes (PLs) as solid templates for high-dose liposomes and consequently, to enhance the oral bioavailability and therapeutic effect of BBR. An air-suspension coating (layering) method was used for generating BBR-loaded PLs. The size, distribution size, morphology, and entrapment efficiency (EE) of the final reconstituted liposomes were assessed. The oral bioavailability and endogenous cholesterol lowering effects of BBR loaded in liposomes were investigated in rats and mice, respectively. The BBR-loaded PLs showed a smooth BBR-embedded film around micron-scale carrier particles (mannitol). The reconstituted BBR-loaded liposomes had a nano-scale average size (116.6 ± 5.8 nm), narrow size distribution (polydispersity index, PDI 0.269 ± 0.038), and high EE (87.8 ± 1.0%). The oral bioavailability of reconstituted BBR-loaded liposomes at a dose of 100 mg/kg in rats was increased even 628% compared to that obtained with pure BBR (according to 90% confidence interval). The BBR-loaded liposomes at the daily oral dose 100 mg/kg in P-407- reduced total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) in hyperlipidemic mice by 15.8%, 38.2%, and 57.0%, respectively.

Scanning probe analysis of twisted graphene grown on a graphene/silicon carbide template

Overlayer growth of graphene on an epitaxial graphene/silicon carbide (SiC) as a solid template by ethanol chemical vapor deposition is performed over a wide growth temperature range from 900 °C to 1450 °C. Structural analysis using atomic force and scanning tunneling microscopies reveal that graphene islands grown at 1300 °C form hexagonal twisted bilayer graphene as a single crystal. When the growth temperature exceeds 1400 °C, the grown graphene islands show a circular shape. Moreover, moiré patterns with different periods are observed in a single graphene island. This means that the graphene islands grown at high temperature are composed of several graphene domains with different twist angles. From these results, we conclude that graphene overlayer growth on the epitaxial graphene/SiC solid at 1300 °C effectively synthesizes the twisted few-layer graphene with a high crystallinity.

Fluoride-free synthesis of beta zeolite with enrichment of polymorph B from a solvent-free route.

Beta zeolite with enrichment of polymorph B is successfully synthesized in the absence of fluorine species under solvent-free conditions. The phase composition of polymorph B in the sample is about 70%.

Robust and highly adaptable high internal phase gel emulsions stabilized solely by a natural saponin hydrogelator glycyrrhizic acid.

Herein, we report a new class of high internal phase gel emulsions (gel-HIPEs) that are mechanically robust, adaptable, and processable. They can be synthesized facilely by using the natural food-grade saponin glycyrrhizic acid (GA) as the sole stabilizer, which is shown to be versatile for various oils. The structural properties of these HIPEs including appearance, viscoelasticity and processability are well controlled by simply changing the concentration of GA nanofibrils. When the GA nanofibril concentration exceeds 0.3 wt%, the unique gel-HIPEs can be produced through the formation of fibrillar hydrogel networks in the continuous phase. When the nanofibril concentration only increases to 5 wt%, it is surprising to see that these gel-HIPEs display an extremely high mechanical strength, and the storage moduli as well as the yield stress values can reach 408.5 kPa and 3340 Pa (or even more), respectively. We conjecture that such remarkable mechanical performance is mainly attributed to the highly viscoelastic GA nanofibrillar networks in the continuous phase of gel-HIPEs, which can actively trap the nanofibril-coated emulsion droplets and thus strengthen the gel matrix. Consequently, the robust gel-HIPEs can be used as a solid template to fabricate stable porous materials without the need for crosslinking of the continuous phase, and the open- and closed-cell foam microstructures are controlled by the nanofibril concentration. Furthermore, the nanofibril-based HIPEs are promising long-term delivery vehicles with controlled-release properties for lipophilic active cargoes, since the strong fibrillar networks at the droplet surfaces and in the continuous phase can effectively retard the active release.

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing.

In this study, we report a flexible implantable 4-channel microelectrode probe coated with highly porous and robust nanocomposite of poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanofiber (CNF) as a solid doping template for high-performance in vivo neuronal recording and stimulation. A simple yet well-controlled deposition strategy was developed via in situ electrochemical polymerization technique to create a porous network of PEDOT and CNFs on a flexible 4-channel gold microelectrode probe. Different morphological and electrochemical characterizations showed that they exhibit remarkable and superior electrochemical properties, yielding microelectrodes combining high surface area, low impedance (16.8 ± 2 MΩ µm2 at 1 kHz) and elevated charge injection capabilities (7.6 ± 1.3 mC/cm2) that exceed those of pure and composite PEDOT layers. In addition, the PEDOT-CNF composite electrode exhibited extended biphasic charge cycle endurance and excellent performance under accelerated lifetime testing, resulting in a negligible physical delamination and/or degradation for long periods of electrical stimulation. In vitro testing on mouse brain slices showed that they can record spontaneous oscillatory field potentials as well as single-unit action potentials and allow to safely deliver electrical stimulation for evoking field potentials. The combined superior electrical properties, durability and 3D microstructure topology of the PEDOT-CNF composite electrodes demonstrate outstanding potential for developing future neural surface interfacing applications.

Composition-controlled degradation behavior of macroporous scaffolds from three-armed biodegradable macromers

Acidification of implant microenvironment and inflammation due to degradation products of high molecular weight poly(α‑hydroxy acids) like PLA and PLGA is a risk that can limit their use in regenerative medicine, tissue engineering and drug delivery. We developed macromers that consist of a three-armed core with varying degrees of ethoxylation, hydrolytically degradable oligolactide blocks and terminal methacrylate groups (TriLA macromers) for cross-polymerization into monolithic or macroporous structures. Within the macromer platform, biophysical and biochemical properties can be adjusted by macromer chemistry. In this work, eight new macromer types with a reduced degree of methacrylation or substitution of a fraction of the lactic acid units with glycolic acid were successfully synthesized starting from a fully methacrylated, oligolactide-based TriLA macromer. Chemical characterization confirmed feed-dependent glycolic acid integration and controlled reduction in degree of methacrylation. The degradation behavior of macroporous scaffolds made by solid lipid templating from both the previously established and the new macromers was systematically investigated. In general, the scaffolds displayed continuous mass loss over time when the onset time of degradation was passed. Depending on arm length as well as hydrophilicity of the oligomeric building blocks, degradation half-life ranged from 3 to 4 weeks to over 81 weeks. Glycolic acid integration accelerated network degradation more effectively than an increase in core molecule hydrophilicity. The observed, adjustable degradation profiles with only moderate medium acidification and a dominant phase of almost linear mass loss make this material platform promising for regenerative and drug delivery applications.

Design and structure of nitrogen and oxygen co-doped carbon spheres with wrinkled nanocages as active material for supercapacitor application

Nitrogen/oxygen co-doped carbon spheres with wrinkled nanocages (NOCN) were successfully synthesized using dendritic fibrous nanosilica (DFNS) as sacrificial solid template, glucose as a carbon source, and melamine as the nitrogen source. The obtained carbon nanocages (NOCN-850-3) exhibit human brain-like winkle shape, high specific surface area (813 m2 g−1), high nitrogen (16.24 at%) and oxygen contents (5.36 at%). In addition, the obtained carbon presents good specific capacitance of 311.1 F g−1 at a current density of 0.5 A g−1 in 6 M KOH and remarkable rate performance (118.1 F g−1 at a current density of 30 A g−1) and cycle stability (97.6% retention after 10,000 charge–discharge performance cycles at 10 A g−1). Meanwhile, the NOCN-850-3-based coin-type symmetric supercapacitor exhibits a maximum energy density of 12. 3 W h kg−1 at a power density of 175 W kg−1 and also a relatively low resistance in 6 M KOH aqueous electrolyte. Thus, the unique structure and nitrogen/oxygen co-doping characteristic endue the electrode material a potential application in supercapacitors.

Immobilization of size variable Au nanoparticles on surfactant-modified silica and their catalytic application toward 4-nitrophenol reduction: A comparative account of catalysis

Galvanic replacement reaction (GRR) is a widely used powerful synthesis technique to produce different hollow nanoparticles. In the present work, As(0) nanoparticles in two different size ranges (e.g. 50±7 and 70±10 nm) are synthesized by sodium borohydride reduction of arsenite under controlled pH, and subsequently they are used as templates for GRR reaction to produce two different sized hollow gold nanoparticles (HGNPs), which are designated as RHGNPs and BHGNPs (because of their red and blue colors respectively), with average diameter 55±7 and 72±7 nm, respectively. The unique feature of the reduction of arsenite to As(0) and not to AsH3, is the control of medium pH at 7-9. Now the use of RHGNPs and BHGNPs in homogeneous phase restricts them to recollect and reuse properly. So a soft solid template, cationic surfactant-modified silica (SMS) having positive charge in the surface has been considered to ‘adsolubilize’ the RHGNPs and BHGNPs. The ionic attraction between negatively charged surface of both the HGNPs (which arises due to the in-situ stabilization by surface adsorbed H2AsO4⁻) and the positively charged SMS holds them tightly. SMS after the adsorption of RHGNPs on to it looks pinkish-red and the material is designated as RG-SMS. Similarly, SMS after the adsorption of BHGNPs looks bluish-purple and the material is called BG-SMS. This is a unique procedure to prepare RG-SMS and BG-SMS. The catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride has been studied using RG-SMS and BG-SMS (i.e. red and blue HGNPs immobilized in the solid phase) as the catalyst to examine the size effect. While both the nanoparticles exhibit excellent catalytic activity, the smaller particles (Au present in RG-SMS) are observed to be more effective than the larger ones (Au present in BG-SMS). The reaction is carried out with varying catalyst doses and initial 4-NP concentrations and the reaction follows first order kinetics in all cases. The first order rate constant values obtained are 0.0667 min−1 and 0.0257 min−1 for RG-SMS and BG-SMS respectively at a dose of 0.041 g L−1 and at 4-NP concentration 9.9 × 10−5 M. The turnover frequency (TOF) obtained at a dose 0.041 g L−1 are 0.0159 per minute and 0.0079 per min for the catalytic reaction using RG-SMS and BG-SMS, respectively. The results suggest that RG-SMS bears ∼2 times higher catalytic activity than that of BG-SMS. The reusability of both catalysts up to the 4th cycle has been checked. The catalytic activity of the HGNPs in the solution phase and the solid phase (i.e. on SMS) are compared. It has been observed that solution phase catalysts are better in terms of activity but solid supported catalysts are better in terms of their shelf-life and ease of application.

Promoting the solar-light-driven mesoporous BaFe12O19/g-C3N4 photocatalysts for photoreduction and removal of Hg(II) ions

In this contribution, synthesis of BaFe12O19/g-C3N4 nanocomposites with mesostructured and large surface area for the first time utilizing both soft and solid templates has been achieved for Hg(II) photoreduction in aqueous solution. XRD results indicated the construction of single-phase BaFe12O19 without impurities phases. BaFe12O19 particles (10 nm) are highly distributed onto g-C3N4 surface. Mesoporous 3% BaFe12O19/g-C3N4 nanocomposite was exhibited a considerable photoreduction rate of Hg(II) about 940 µmolg−1h−1 and ∼100% removal efficiency during 30 min illumination time compared with the pristine either g-C3N4 (75.20 µmolg−1h−1, 15%) or mesoporous BaFe12O19 (163.88 µmolg−1h−1, 30%). The Hg(II) reduction rate over 3% BaFe12O19/g-C3N4 nanocomposite was enhanced 5.74 and 12.50 fold larger than BaFe12O19 and g-C3N4.The rate constant over 3% BaFe12O19 /g-C3N4 nanocomposite was promoted 21 and 9.5 fold larger than g-C3N4 and BaFe12O19. The enhancement photoreduction efficiency of BaFe12O19/g-C3N4 nanocomposites could be referred to, the accessible surface area and the synergistic effect and small particle size, which can expedite photoinduced charge separation and facilitate Hg(II) reduction process. The synthesized photocatalysts are appropriate candidates with narrow bandgap value for visible light photocatalysis reactions owing to the construction of BaFe12O19/g-C3N4 nanocomposites. After the Hg(II) photoreduction reaction, the collection and recycling of photocatalyst could be readily completed.

Design of macroporous photo-cationically cured resorcinol-based epoxy resins coupled to a solid template technique

This paper presents for the first time an eco-friendly combination of cationic photopolymerization and the solid template technique to obtain macroporous epoxy resins from resorcinol diglycidyl ether (RDGE) with defined cell size and distribution. The polymerization was performed by cationic polymerization under UV irradiation in the presence of NaCl particles template sintered through the spark plasma sintering process (SPS). After removal of NaCl by water, a porous material with interconnected pores was obtained. The influence of processing parameters, i.e., reactant contents, UV irradiation time, and post-curing conditions on the reticulation achievement and the thermomechanical behavior have been pointed out. Mechanical, physical, acoustic and morphological properties were deeply investigated. For instance, the specific compressive modulus is of 50.9 MPa cm3.g−1 for a density of 0.224 g.cm−3 and the glass transition is around 137 °C, which makes this system an interesting alternative for sustainable building materials.

Island formation and the heterogeneous nucleation of aluminum

Liquid phase epitaxy of aluminum on substrates of varying lattice spacing is investigated. Molecular dynamic simulations show the formation and growth of small (nm to µm) islands following a Stranski-Krastanov mode, where a few unit cell thick, solid layer first templates to the substrate. Subsequent island formation reduces the strain energy within the nucleating solid. Growing islands coalesce upon impinging, while misfit dislocations form during growth and remain at the substrate interface. A thermodynamic analysis reveals island creation is a stochastic process, requiring thermal energy to overcome an activation barrier. Relative to a planar growth criterion, island growth becomes the prominent mechanism at moderate lattice mismatch between the solid and substrate. The difference in activation undercooling between the two growth mechanisms increases with mismatch magnitude. The presented model is used to evaluate island growth for other metals, and can be used as a criterion for activation of a catalyzing surface.

Review of The Game Audio Strategy Guide

Review of <i>The Game Audio Strategy Guide</i>

The application of zinc citrate for the synthesis of carbon materials

Zinc citrate was prepared and its thermal decomposition was investigated by methods of thermogravimetric analysis and differential scanning calorimetry. Products of the thermal decomposition were investigated by X-ray diffraction analysis. The decomposition proceeds at temperatures 50 - 420 °C in three stages and leads to the formation of nanocrystalline ZnO with the average grain size of 23 nm. Subsequently, zinc citrate was used as a precursor of ZnO hard template for preparation of carbon mesoporous materials by the solid template method. The carbon materials were obtained by pyrolysis of polymer matrix of phenol-formaldehyde resin in which zinc citrate was added. It was found that the resulting material has a specific surface area of 1051 m2/g. According to the cyclic voltamperometry data, the material has a specific capacity 40 F/g.

Liquid‐State Templates for Constructing B, N, Co‐Doping Porous Carbons with a Boosting of Potassium‐Ion Storage Performance

AbstractTemplate‐assistant design and fabrication of porous carbon electrode materials has experienced great progress throughout the past decades and yielded lots of successes via various gas or solid state templates. Nevertheless, liquid‐state templates are rather rare in preparing porous carbon materials to date. In this work, melting B2O3 beads are used as both templates and a B dopant, leading to unique B, N co‐doping hierarchically porous carbons containing a “bubble pool”‐like skeleton built of interconnected carbon nanobubbles. Notably, an interesting amending effect of doped B atoms on the N‐doped carbon network can be identified for the first time, which creates a “paddy field”‐like hybrid microstructure with the co‐existence of sp2 short‐range order and sp3 defective areas, leading to an ideal model of carbon materials with both good conductivity and high capacity. Together with the rich ion diffusing pathways and the structural integrity of the “bubble pool”‐like skeleton, the resultant electrode delivers a comprehensive K‐ion storage performance. Therefore, the findings demonstrate the unique pore‐making merits of liquid state templates, which may open the door for exploring porous carbons with more innovations of microstructures and functionalities for applications in energy storage and other fields.

Mechanically Compliant Thermal Interfaces Using Biporous Copper‐Polydimethylsiloxane Interpenetrating Phase Composite

AbstractThermal interface materials are essential for thermal management in electronics packaging by providing a low resistance thermal pathway between heat sources and heat sinks. Nanostructured materials can be potential candidates for the next‐generation interface materials by coupling their high thermal conductivity and mechanical compliance, suppressing failure even after large numbers of thermal cycles. This work investigates the thermal and mechanical characteristics of a new type of thermal interface materials, consisting of metal/elastomer interpenetrating phase composites. The 3D, highly porous copper scaffolds are fabricated via a fast and simple in situ bubble‐templated electrodeposition process without the presence of solid templates; subsequently, the void fraction of the composite is filled by elastomer infiltration. The presence of elastomer matrix demonstrates limited impact on the thermal conductivity of the composite while it contributes substantially to the mechanical properties, providing the structural flexibility required. Thermal resistance values of 1.2–4.0 cm2 K W–1 are measured upon multiple thermal cycles, confirming the mechanical stability of the composite, without showing any noticeable degradation.

SnO2/ZnSnO3 double-shelled hollow microspheres based high-performance acetone gas sensor

In this study, the preparation process and the sensing performance toward acetone of SnO2/ZnSnO3 composite microspheres with the double-shelled hollow structure were reported. It was synthesized by one-step chemical vapor deposition (CVD) method using sucrose as solid precursor pyrolysis carbon template. In addition, the internal structure of the composite microspheres can be effectively controlled by changing the sucrose concentration. The perfect double-shelled hollow structure (average diameter of about 500 nm) of the prepared sensitive materials was observed through SEM and TEM. It is noteworthy that the double-shelled hollow structure had a large specific surface area (188.60 m2/g), which can both increase the internal and external reactive sites of the sensitive material effectively. Compared with other obtained composite microspheres, the SnO2/ZnSnO3 sample with double-shelled hollow structure presented the best sensing performance, and the response to 100 ppm acetone reached 30 at 290 °C. Furthermore, it also presented excellent selectivity and long-term stability to acetone. The excellent performance was attributed to the synergistic effect of the double-shelled hollow structure with large specific surface area and the n-n heterojunction at the interface of the SnO2/ZnSnO3 composite. The sensing mechanisms of the double-shelled hollow SnO2/ZnSnO3 composite material were discussed in detail.

Kidney–Targeted drug delivery systems based on tailor-made nanocapsules

Podocyte damage plays a central role in the pathogenesis of idiopathic nephrotic syndrome, as well as in the progression of many chronic glomerular diseases. Targeted therapy in these diseases still represents a challenge. We have previously shown that c-mip (c-maf inducing protein) plays a pivotal role in podocyte diseases in minimal change nephrotic syndrome patients. In this context, we implement a non-viral approach targeting the expression of c-mip in podocytes to reduce proteinuria. This therapeutic approach is based on nanovectors composed by chitosan and plasmids coding for micro-Ribonucleic Acid (miRNA) against c-mip. The overall elaboration process, monitored by absorbance and zeta potential measurements, relies on the alternate deposition of these biopolymers with opposite charges onto gold colloidal nanoparticles used as solid template (characterized by transmission electron microscopy TEM and Small-angle X-ray scattering SAXS measurements). Their hydrolysis lead to hollow nanostructures, also called nanocapsules (evidenced by TEM analysis). From this approach, crucial parameters impacting the biological assay can be easily investigated in particular (i) the size, (ii) the number of plasmid layers and (iii) the presence of the solid template. The efficiency of the synthesized nanomaterial will be tested in different conditions on Human Embryonic Kidney cells (HEK), immortalized podocytes and in vivo on a mouse podocyte damage model. To our knowledge, this is the first experiment including designed Deoxyribonucleic acid (DNA) derived nanocapsules to reach podocytes.

Exploration of TRPM8 Binding Sites by β-Carboline-Based Antagonists and Their In Vitro Characterization and In Vivo Analgesic Activities.

Transient receptor potential melastatin 8 (TRPM8) ion channel represents a valuable pharmacological option for several therapeutic areas. Here, a series of conformationally restricted derivatives of the previously described TRPM8 antagonist N,N′-dibenzyl tryptophan 4 were prepared and characterized in vitro by Ca2+-imaging and patch-clamp electrophysiology assays. Molecular modeling studies led to identification of a broad and well-defined interaction network of these derivatives inside the TRPM8 binding site, underlying their antagonist activity. The (5R,11aS)-5-(4-chlorophenyl)-2-(4-fluorobenzyl)-5,6,11,11a-tetrahydro-1H-imidazo[1′,5′:1,6]pyrido[3,4-b]indole-1,3(2H)-dione (31a) emerged as a potent (IC50 = 4.10 ± 1.2 nM), selective, and metabolically stable TRPM8 antagonist. In vivo, 31a showed significant target coverage in an icilin-induced WDS (at 11.5 mg/kg ip), an oxaliplatin-induced cold allodynia (at 10–30 μg sc), and CCI-induced thermal hyperalgesia (at 11.5 mg/kg ip) mice models. These results confirm the tryptophan moiety as a solid pharmacophore template for the design of highly potent modulators of TRPM8-mediated activities.

Ultrarobust and Biomimetic Hierarchically Macroporous Ceramic Membrane for Oil-Water Separation Templated by Emulsion-Assisted Self-Assembly Method.

Reported herein is a novel ultrarobust and biomimetic hierarchically macroporous ceramic membrane that can achieve a high efficiency of up to 99.98% for oil-water separation, while the efficiency remains nearly unchanged even after 10 rounds of use and storage for up to 4 months. The macroporous ceramic membrane is prepared by combining surface hydrophobic coating with an emulsion-assisted template self-assembly of the modified Al2O3 ceramic powder. The as-prepared ceramic membrane is a lightweight material with high strength because the relative density is only ∼1.02 g/cm3; the compressive strength of the as-prepared ceramic membrane is expected to be 15-fold higher than that of the sample prepared using the traditional solid template approach even at a higher porosity due to the principle of self-assembly of Al2O3 particles. It is the mechanism of self-assembly that has broken the traditional principle in ceramic preparation that leads to a perfectly dense packing structure. Moreover, the ceramic membrane maintained excellent oil-water separation efficiency, because of which even after its top layer was damaged by sand impingement, superfine particles could be separated using our macroporous membrane due to the featured interconnected pore structure. We anticipate that this example of the combination of a superwettability theory and a traditional ceramic material can provide an important application direction of advanced oil-water separation techniques.

Synthesis of high‐surface area mesoporous SiC with hierarchical porosity for use as catalyst support

AbstractPorous SiC with a hierarchical mesoporous structure is a promising material for high‐performance catalytic systems because of its high thermal conductivity, high chemical inertness at high temperature, and oxidation resistance. Attempts to produce high‐surface area hierarchical SiC have typically been made by using porous carbon as a template and reacting it with either Si or SiO2 at high temperature under inert atmosphere. Because the reaction mechanism with Si involves a carbon dissolution step, and the reaction with SiO2 is highly dependent on C‐SiO2 dispersion, the porous structure of the carbon template is not maintained, and the reaction yields nonporous SiC. In this work, mesoporous SiC has been synthesized using a novel hard‐template methodology. SiC was prepared from hierarchical (mesoporous) silica which served as a solid template. Carbon deposition was done by Carbon Vapor Deposition (CVD) using CH4 as carbon precursor, where different temperatures and reaction times were tested to optimize the carbon coating. The synthesized SiC retained 61 (118 m2/g) and 47% (0.3 cm3/g) of the BET surface area and the mesopore volume of the original SiO2, which is 10 times higher than the retention reported for other template methods used to produce high surface area SiC.