Morphology Of Microspheres Research Articles

Preparation of diatomite-based SA@ZIF-8 composite microspheres by electrostatic spray method and its adsorption performance for Cu(II)

Diatomite (DE)-based sodium alginate (SA) loaded ZIF-8 composite microspheres were prepared by high-voltage electrostatic spray technology. SA/DE microspheres were prepared by SA and acid-base-regulated silica sol solution. Ultra-small ZIF-8 was grown on SA/DE microspheres by in-situ synthesis method to obtain ultra-high specific surface area composite microspheres. The morphology and particle size of the composite microspheres were analyzed by SEM, and characterized by FT-IR, XRD and TGA. The optimum adsorption efficiency were achieved by a series of conditions optimization. The adsorption of Cu(II) by SA/DE@ZIF-8 conforms to the Langmuir adsorption model, and the theoretical maximum adsorption capacity is 599.07 mg/g. In summary, this study opens up a new strategy for the design of efficient and easily recycled ZIF-8 composite microspheres for water treatment.

Influence of particle size on electrorheological effect of poly(ionic liquid) microsphere suspensions

Hydrophobic poly(ionic liquid) microspheres with different sizes are prepared via cooling assisted phase separation method. The morphology and structure of microspheres are characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The effect of particle size on the electrorheological effect of the poly(ionic liquid) microsphere suspensions is studied by rheological test under electric fields. It shows that the shear stress at zero electric field decreases with the increase of particle size, while yield stress and electric field-induced shear stress increase with the increase of particle size. The electric field dependence of yield stress and electric field-induced shear stress increment is independent of particle size.

Process parameter optimisation for manufacturing porous bioactive silicate glass microspheres via flame spheroidisation: The goldilocks effect

This study investigated the influence of flame spheroidisation process parameters for successfully manufacturing solid (dense) and highly porous microspheres from Food and Drug Administration approved bioactive 45S5 glass and 45S5 with addition of viscosity modifiers (i.e. 2 and 5 mol% borax and V2O5), compared against successfully processed phosphate glass microspheres (termed P40). Characterisation studies performed included thermal analysis (SDT), glass viscosity measurements using high temperature rotational viscometry and hot stage microscopy, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis.This study revealed that aside from intrinsic material properties (i.e. melt temperature and viscosity profiles), process parameters including starting glass particle size, cooling rate and gas flow rates were important factors in achieving the desired porous glass microsphere morphology. Considering the above influential factors, a processing model has been proposed for the manufacture of highly porous microspheres from bioactive silicate glasses.

Microencapsulated bufalin: From membrane preparation to microspheres tailoring, and sustained release

Microspheres are commonly implemented in drug delivery system to enhance drug bioactivity and reduce the toxicity. Membrane emulsification is a promising technique to be applied in the preparation of microspheres for sustained release due to its easy control of the particle size. Membranes with different properties on dual sides have shown superior properties in the application of membrane emulsification. In this work, membranes with open channels and sharp pore size distribution were prepared by the novel combined solvent crystallization and polymer diffusion (CCD) technique. For the first time, the feasibility of CCD membranes with dual properties were verified for the application of membrane emulsification. Bufalin-poly(lactic-co-glycolic acid) (PLGA) microspheres were successfully prepared and the size distribution could be tuned via adopting CCD membranes with different pore sizes. The effects of membrane wettability and pore size on microspheres production were investigated for the membranes prepared by four different cooling conditions. The morphologies of microspheres were obtained by scanning electron microscope and the size distribution was analyzed by ImageJ. The in vitro release of bufalin-PLGA microspheres in various sizes exhibited distinctively, indicating the capability of controlling the release rate of the drug system via changing membrane with different properties. In this study, the most uniformly distributed bufalin-PLGA microspheres with an average size of 0.47 µm were achieved through membrane emulsification using the optimal CCD membranes. The as-prepared bufalin-PLGA microspheres exhibited an IC50 of 231.7 µg/mL, achieving reduced toxicity than free bufalin. This study provides a novel approach on tailoring microspheres via the manipulation of membrane properties, facilitating the design and production of drug delivery system with desired properties for a wide range of purposes.

Design and synthesis of Ni3ZnC0.7 catalyst derived from a bimetallic Ni/Zn metal-organic frameworks for efficient synthesis of 2-arylbenzimidazole

Developing efficient bimetallic Ni/Zn metal organic frameworks (MOFs) derived Ni3ZnC0.7 alloy catalyst for cyclization reactions is highly anticipated. Bimetallic Ni/Zn-PTA MOFs with flower-like microspheres morphology was synthesized by using a facile hydrothermal method and used as a precursor for preparation of the catalyst. Then, a ZnO supported Ni-Ni3ZnC0.7 incorporated carbon catalyst (Ni-Ni3ZnC0.7/ZnO-C) was obtained by deriving from the Ni/Zn-PTA MOFs through one-step pyrolysis. The developed Ni-Ni3ZnC0.7/ZnO-C catalyst was used as a recoverable heterogeneous catalyst for synthesis of 2-arylbenzimidazoles by cyclization reaction of phenylmethanamines and 2-nitroanilines in good yields. Various characterizations (e.g. SEM/EDX, XRD, TEM, FT-IR, XPS and Raman) revealed that the catalyst exhibited good performance for cyclization reaction, which are ascribed to particular hierarchical structure, as well as synergistic effect between Ni and Ni3ZnC0.7. As a result, the Ni-Ni3ZnC0.7/ZnO-C catalyst showed excellent stability and activity for the condensation cyclization reaction. This bimetallic MOFs-derived Ni-Ni3ZnC0.7 catalyst opens up a potential way for fabricating other Carbon supported alloy catalysts in heterogeneous catalysis reactions.

Effect of the Nature and Concentration of the Fuel on the Structure and Morphology of ZnO Microspheres Produced via Spray Solution Combustion Synthesis

Effect of the Nature and Concentration of the Fuel on the Structure and Morphology of ZnO Microspheres Produced via Spray Solution Combustion Synthesis

Modified porous starches loading curcumin and improving the free radical scavenging ability and release properties of curcumin

Maize porous starch-curcumin microspheres were prepared by encapsulating curcumin into cross-linked porous starch and oxidized porous starch to investigate the effect of modified porous starch in embedding and protecting curcumin. The morphology and physicochemical properties of microspheres were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, Zeta/DLS, Thermal stability, and antioxidant activity; the release of curcumin was evaluated with a simulated gastric-intestine model. The FT-IR results revealed that curcumin was amorphously encapsulated in the composite and hydrogen bond formation between starch and curcumin was one of the major driving forces for encapsulation. Microspheres increased the initial decomposition temperature of curcumin, which has a protective effect on curcumin. Modification improved the encapsulation efficiency and the scavenging free radical ability of porous starch. The release mechanism of curcumin from microspheres fits first-order and Higuchi models well in gastric and intestinal models, respectively, indicating that encapsulation of curcumin within different porous starches microspheres enables controlled release of curcumin. To recapitulate, two different modified porous starch microspheres improved the drug loading, slow release and free radical scavenging effects of curcumin. Among them, the cross-linked porous starch microspheres had higher encapsulation and slow release ability for curcumin than the oxidized porous starch microspheres. It provides theoretical significance and data basis for the encapsulation of active substances by modified porous starch.

Synergistic synthesis of Carrisa edulis fruit extract capped heterogeneous CuO-ZnO-HNT composite for photocatalytic removal of organic pollutants

Photocatalysis is a promising strategy for treating harmful pollutants in the ecosystem. Recently, the use of semiconductor photocatalysts to remove organic dyes and pharmaceutical drugs from polluted water has gained a lot of interest. In this work, initially, CuO-ZnO composite was synthesized using microwave method utilizing Carrisa edulis fruit extract as capping/stabilizing agent. Secondly, heterogeneous CuO-ZnO-Halloysite nanotube (HNT) photocatalyst have been synthesized via ultrasonication method. The synthesized composite was confirmed by various characterization techniques such as X-ray diffraction (XRD), UV–vis-DRS Spectroscopy (UV–vis-DRS), Fourier-Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Analysis (EDAX), Brunauer Emmette Teller analysis (BET), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric analysis (TGA) and Zeta Potential. The resultant CuO-ZnO-HNT composite possesses narrow band gap, large surface area with microsphere morphology. Under visible light irradiation, the synthesized composite was evaluated for photocatalytic activity against Congo Red (CR) and Tetracycline (TC). It is observed that within 70 min of irradiation, the 20CZ-HNT composite showed 86 % and 90 % degradation of CR and TC respectively. The reusability test showed that the catalyst was stable even after five cycles. As a result, the CuO-ZnO-HNT composite exhibits great promise for photocatalytic removal of environmental pollutants utilizing visible light.

Photoaging of polystyrene microspheres causes oxidative alterations to surface physicochemistry and enhances airway epithelial toxicity.

Microplastics represent an emerging environmental contaminant, with large gaps in our understanding of human health impacts. Furthermore, environmental factors may modify the plastic chemistry, further altering the toxic potency. Ultraviolet (UV) light is one such unavoidable factor for airborne microplastic particulates and a known modifier of polystyrene surface chemistry. As an experimental model, we aged commercially available polystyrene microspheres for 5 weeks with UV radiation, then compared the cellular responses in A549 lung cells with both pristine and irradiated particulates. Photoaging altered the surface morphology of irradiated microspheres and increased the intensities of polar groups on the near-surface region of the particles as indicated by scanning electron microscopy and by fitting of high-resolution X-ray photoelectron spectroscopy C 1s spectra, respectively. Even at low concentrations (1-30 µg/ml), photoaged microspheres at 1 and 5 µm in diameter exerted more pronounced biological responses in the A549 cells than was caused by pristine microspheres. High-content imaging analysis revealed S and G2 cell cycle accumulation and morphological changes, which were also more pronounced in A549 cells treated with photoaged microspheres, and further influenced by the size, dose, and time of exposures. Polystyrene microspheres reducedmonolayer barrier integrity and slowed regrowth in a wound healing assay in a manner dependent on dose, photoaging, and size of the microsphere. UV-photoaging generally enhanced the toxicity of polystyrene microspheres in A549 cells. Understanding the influence of weathering and environmental aging, along with size, shape, and chemistry, on microplastics biocompatibility may be an essential consideration for incorporation of different plastics in products.

Charge Redistribution of Co9S8/MoS2 Heterojunction Microsphere Enhances Electrocatalytic Hydrogen Evolution.

The electrocatalytic hydrogen evolution activity of transition metal sulfide heterojunctions are significantly increased when compared with that of a single component, but the mechanism behind the performance enhancement and the preparation of catalysts with specific morphologies still need to be explored. Here, we prepared a Co9S8/MoS2 heterojunction with microsphere morphology consisting of thin nanosheets using a facile two-step method. There is electron transfer between the Co9S8 and MoS2 of the heterojunction, thus realizing the redistribution of charge. After the formation of the heterojunction, the density of states near the Fermi surface increases, the d-band center of the transition metal moves downward, and the adsorption of both water molecules and hydrogen by the catalyst are optimized. As a result, the overpotential of Co9S8/MoS2 is superior to that of most relevant electrocatalysts reported in the literature. This work provides insight into the synergistic mechanisms of heterojunctions and their morphological regulation.

Mesoporous single-crystal-based TiO2 microspheres decorated by carbon nitride for obviously improved photocatalytic performance and recyclability

A novel porous TiO2 (PT) with mesoporous single-crystal-based microsphere morphology has been synthesized by a hard-template method and then decorated by graphitic carbon nitride (g-C3N4, CN) nanosheets. The prepared composites (CN/PT) exhibit improved photocatalytic activity in degradation of methylene blue (MB) compared to nonporous bulk TiO2 (BT), PT and g-C3N4, and much better recyclability than commercial P25 TiO2. The enhancement of photocatalytic activity of composites can be attributed to the increased active sites on PT surfaces, and the Z-scheme heterojunction promoting charge separation of photogenerated carriers.

Nanorod coordination polymers for needle trap extraction of E-cigarettes and cigarettes smoke

Nowadays, the issue of e-cigarettes gaining popularity among never-smokers and teenagers, thus becoming an emergent public health problem. Consequently, developing methods to monitor the toxic compounds in their smoke is a lucrative object. Herein, two coordination polymers (CPs) with nanorod and microsphere morphology are proposed as extractive phases in a needle trap device (NTD). The two synthesized CPs were characterized by FT-IR, SEM, BET, EDS, XPS and TGA. The extraction efficiency of two synthesized CPs was compared for polyaromatic hydrocarbons (PAHs) and as a result, the nanorods exhibited higher extraction and desorption efficiency. The prepared NTD filled with the nanorod CP was implemented to the analysis of cigarettes and e-cigarette smoke. All the influencing parameters on PAHs analysis and gas chromatography (GC) procedure were investigated and optimized. The CP with nanorod morphology was applied to develop an NTD–GC–MS method for quantification of PAHs, as model analytes in the cigarettes and e-cigarettes smoke. The prominent extractive–phase was found to be very sensitive for the determination of PAHs with reliable figures of merit, such as acceptable linearity (0.2–750 ng/L), low limits of detection (LODs), 0.05–5 ng/L, suitable intra–day and inter–day relative standard deviations (RSD% <12 %), and long lifespan (number of uses >100 times).

A conversion strategy on photo-response bifunctional motor enriched with oxygen vacancies enable lignin depolymerization

Overconsumption of fossil energy is mitigated by conversion of lignin to higher value products in the pulp and paper industry, where the breakage of the β-O-4 linkages plays a prominent role as the core technology. Herein, a photo-response motor (Au–H–TiO2) using water as fuel was prepared by using the one-step solvent volatilization method to break the β-O-4 linkages in lignin models under visible light irradiation. The Au–H–TiO2 with microscopic morphology of H-doped surface oxygen-deficient TiO2 microspheres semi-encapsulated by Au layers exploits the liquid flow difference formed by the proton elimination reaction occurring on the TiO2 hemispherical surface encapsulated by Au layers (Au hemispherical surface) as the power source of driving photocatalysis. Structural and spectroscopic analyses confirm that the abundant oxygen vacancies possess the ability to prolong the separation time of photogenerated carriers on the TiO2 hemispherical surface not encapsulated by Au layers (TiO2 hemispherical surface) and achieve an efficient visible light response by building a new band gap within the forbidden band. Simultaneously, the oxygen vacancies on the Au hemispherical surface act as photoelectron trapping sites to accelerate the movement rate of Au–H–TiO2 by promoting the elimination of protons. Notably, Au–H–TiO2 fueled by visible light and water can drive the synergistic vibration of the lignin models to ensure its uniform dispersion in water and complete the breakage of the β-O-4 linkages of the lignin models within 240 min without external mechanical assistance. Herein, it is predicted that high-value utilization of lignin using solar radiation as a single influencing factor has a promising research value.

3D highly porous microspherical morphology of NiO nanoparticles for supercapacitor application

3D highly porous microspherical morphology of NiO nanoparticles for supercapacitor application

(001)-TiO2 nanosheets loaded on BiOI improve carrier separation and enhance the photocatalytic activity

(001)-TiO2/BiOI photocatalysts with microsphere morphology were synthesized by a solvothermal method.

Approaching high-performance lithium storage materials of CoNiO2 microspheres wrapped coal tar pitch-derived porous carbon.

Ternary transition metal oxides (TMOs) are deemed as promising anode materials of Li-ion batteries (LIBs) owing to their large theoretical capacity and rich redox reaction. Nevertheless, the inherent semiconductor characteristic and enormous volume variation of TMOs during cycling bring about sluggish reaction kinetics, fast capacity fading, and poor rate capability. In this study, three-dimensional (3D) porous CoNiO2@CTP architectures, i.e., CoNiO2 microspheres combined with coal tar pitch-derived porous carbon, were designed and synthesized through a one-step hydrothermal method followed by a heat treatment process for the first time. The microsphere morphology increases the contact area between the anode and electrolyte, shortens the transport distance of Li+ ions, and reduces the agglomeration. The existence of the CTP layer provides rich charge transmission paths, improves the electronic conductivity of CoNiO2 and provides abundant active sites for Li+ storage. Owing to the synergistic effect of porous carbon and microsphere morphology of CoNiO2, the CoNiO2@CTP (10.0 wt%) anode shows remarkable electrochemical performance with a high charge capacity (1437.5 mA h g-1 at 500 mA g-1), good rate performance (839.76 mA h g-1 even at 1 A g-1), and remarkable cycle durability (741.4 mA h g-1 after 1000 cycles at 1 A g-1), which is significantly better than pristine CoNiO2. This study not only provides a simple strategy for high-value utilization of CTP but also offers cost-effective CoNiO2@CTP architectures for high-performance LIBs.

Fabrication of magnesium-doped porous polylactic acid microsphere for bone regeneration.

Biodegradable polymer microspheres that can be used as drug carriers are of great importance in biomedical applications, however, there are still challenges in controllable preparation of microsphere surface morphology and improvement of bioactivity. In this paper, firstly, poly(L-lactic acid) (PLLA) was synthesised by ring-opening polymerisation under anhydrous anaerobic conditions and further combined with the emulsion method, biodegradable PLLA microspheres (PM) with sizes ranging from 60-100 μm and with good sphericity were prepared. In addition, to further improve the surface morphology of PLLA microspheres and enhance their bioactivity, functionalised porous PLLA microspheres loaded with magnesium oxide (MgO)/magnesium carbonate (MgCO3) (PMg) were also prepared by the emulsion method. The results showed that the loading of MgO/MgCO3 resulted in the formation of a porous structure on the surface of the microspheres (PMg) and the dissolved Mg2+ could be released slowly during the degradation of microspheres. In vitro cellular experiments demonstrated the good biocompatibility of PM and PMg, while the released Mg2+ further enhanced the anti-inflammatory effect and osteogenic activity of PMg. Functionalised PMg not only show promise for controlled preparation of drug carriers, but also have translational potential for bone regeneration.

P-doped hard carbon microspheres for sodium-ion battery anodes with superior rate and cyclic performance

P-doping regulates the morphology and microscopic characteristics of hard carbon microspheres to obtain excellent rate and cyclic sodium storage performance. This study provides a method for preparing high-performance P-doped hard carbon.

Preparation and morphology control of porous microspheres of different crystalline polymers

Controlling the surface morphology of degradable polymer porous microspheres with alkanes as porogens using the emulsion solvent evaporation method.

Are Fractal-Like Structures Beneficial for Supercapacitor Applications? A Case Study on Fe2O3 Negative Electrodes

The question of whether fractal-like structures are beneficial for supercapacitor applications is investigated by hydrothermally synthesizing Fe2O3 in fern, flake, and microsphere morphologies with similar specific surface areas. Their negative electrodes are prepared by supporting them on nickel foam (NF). The fractal dimensions (FDEIS) of these morphologies estimated from electrochemical impedance spectroscopy are ∼2.50, ∼2.36, and ∼2.19, respectively. The Fern@NF electrode exhibits the highest specific capacitance (Csp) of ∼2708 and ∼104 F g–1 at 1 and 5 A g–1, respectively, with an ∼94% capacitance retention after 2000 cycles. The capacitive (nonfaradaic) surface charge storage contribution from cyclic voltammetry increases with FDEIS from microspheres to ferns. Interestingly, such an increase in FDEIS leads to a decrease in the estimated impedance (ZCPE) in that order enhancing the performance of ferns. Hence, fractal-like structures are beneficial for supercapacitor applications by promoting capacitive surface charge storage through low ZCPE. The emphasis of this work is to study the effect of fractal dimension on the charge storage performance of Fe2O3 electrodes, which is scarcely addressed in the literature. The methodology presented here can be useful in designing/synthesizing a novel supercapacitor material possessing fractal-like structures with a potential for scale-up and commercialization.