Process Optimization of Cu-en/AP Composite Microspheres Preparation by Electrostatic Spray Method Based on ANSYS Simulation

To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.

Research Progress on the Preparation of Inorganic/Natural Materials Composite Microspheres

Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them suitable for preparing microspheres.Inorganic materials(mainly inorganic minerals)have excellent mechanical properties and are inexpensive and easy to obtain.Through the coupling and hybridization of natural polymers and inorganic materials,they can complement each other's advantages and synergistically enhance efficiency,resulting in many excellent physical and chemical properties.Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking,solution mixing,in-situ synthesis,extrusion,etc.The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects,is safe and non-toxic,and the cost of carrier materials is relatively low,which has certain significance for the development of new drug carriers.This article reviews the recent research on the preparation,drug loading and release properties of inorganic material/natural polymer composite microspheres,analyzes the advantages and disadvantages of commonly used preparation methods,and looks forward to the development direction of composite microspheres.

Preparation and characterization of composite microspheres of nano zinc ferrite/poly(D,L-lactide-co-alanine)

Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lactide （D, L-LA） and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.

Hollow Carbon Microspheres/MnO_2 Nanosheets Composites:Hydrothermal Synthesis and Electrochemical Behaviors

This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 m A cm-2, which is a strong promise for high-rate electrochemical capacitive energy storage applications.

Research on properties of hollow glass microspheres/epoxy resin composites applied in deep rock in-situ temperature-preserved coring

Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability,which will lead to the distortion of the petroleum resources reserves assessment.Therefore,the hollow glass microspheres/epoxy resin(HGM/EP)composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring(ITP-Coring),and the physical,mechanical,and temperature preserved properties were evaluated.The results indicated that:As the HGM content increased,the density and mechanical properties of the composites gradually decreased,while the water absorption was deficient without hydrostatic pressure.For composites with 50 vol%HGM,when the hydrostatic pressure reached 60 MPa,the water absorption was above 30.19%,and the physical and mechanical properties of composites were weakened.When the hydrostatic pressure was lower than 40 MPa,the mechanical properties and thermal conductivity of composites were almost unchanged.Therefore,the composites with 50 vol%HGM can be used for ITPCoring operations in deep environments with the highest hydrostatic pressure of 40 MPa.Finally,to further understand the temperature preserved performance of composites in practical applications,the temperature preserved properties were measured.An unsteady-state heat transfer model was established based on the test results,then the theoretical change of the core temperature during the coring process was obtained.The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.

Determination of Triclocarban, Triclosan and Methyl-Triclosan in Environmental Water by Silicon Dioxide/Polystyrene Composite Microspheres Solid-Phase Extraction Combined with HPLC-ESI-MS

This paper developed a sensitive and efficient analytical method for triclocarban (TCC), triclosan (TCS) and Methyl-triclosan (MTCS) determination in environmental water, which involves enrichment by using silicon dioxide/polystyrene composite microspheres solid-phase extraction and detection with HPLC-ESI-MS. The influence of several operational parameters, including the eluant and its volume, the flow rate and acidity of water sample were investigated and optimized. Under the optimum conditions, the limits of detection were 1.0 ng/L, 2.5 and 4.5 ng/L for TCC, TCS, and MTCS, respectively. The linearity of the method was observed in the range of 5-2000 ng/L, with correlation coefficients (r2) >.99. The spiked recoveries of TCC, TCS and MTCS in water sampleswereachieved in the range of 89.5% -96.8% with RSD below 5.7%. The proposed method has been successfully applied to analyze real water samples and satisfactory results were achieved.

Preparation and Properties of Guiqi Polysaccharides/Chitosan/Alginate Composite Hydrogel Microspheres

A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment analysis.The GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release study.The results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in GPcM.The GPcM have a uniform particle size ranging from 395.1μm to 841.5μm.The drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,respectively.The bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 h.The results suggested that the GPcM may have potential application value in drug sustained and controlled release system.

UV-Vis and Surface Photovoltage Spectra of Fe_2O_3/Polystyrene Composite Microspheres

Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.

Dexamethasone-Loaded PLGA Microspheres Incorporated PLLA/PLGA/PCL Composite Scaffold for Bone Tissue Engineering

The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.

Preparation of Dysprosium Ferrite/Polyacrylamide Magnetic Composite Microsphere and Its Characterization

Using the technique of microemulsion polymerization with nano-reactor, dysprosium ferrite/polyacrylamide magnetic composite microsphere was prepared by one-step method in a single inverse microemulsion. The structure, average particle size, morphology of composite microsphere were characterized by FTIR, XRD, TEM and TGA. The magnetic responsibility of composite microsphere was also investigated. The results indicate that the magnetic composite microsphere possess high magnetic responsibility and suspension stability.

A dandelion-like carbon microsphere/MnO_2 nanosheets composite for supercapacitors

This article reported the electrochemical performance of a novel cabon microsphere/MnO2nanosheets(CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy(SEM) and transmission electron microscopy(TEM) revealed that MnO2nanosheets homogeneously grew onto the surface of CMS to form a loose-packed and dandelion-like core/shell microstructure. The unique microstructure plays a basic role in electrochemical accessibility of electrolyte to MnO2active material and a fast diffusion rate within the redox phase. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrometry indicated that the prepared CMS/MnO2composite presented high capacitance of 181 F g-1and long cycle life of 61% capacity retention after 2000 charge/discharge cycles in 1 mol/L Na2SO4solution, which show strong promise for high-rate electrochemical capacitive energy storage applications.

α-MnO_2 nanoneedle-based hollow microspheres coated with Pd nanoparticles as a novel catalyst for rechargeable lithium-air batteries

The hollow α-MnO2 nanoneedle-based microspheres coated with Pd nanoparticles were reported as a novel catalyst for rechargeable lithium-air batteries. The hollow microspheres are composed ofα-MnO2 nanoneedles. Pd nanoparticles are deposited on the hollow microspheres through an aqueous-solution reduction of PdCl2 with NaBH4 at room temperature. The results of TEM, XRD, and EDS show that the Pd nanoparticles are coated on the surface ofα-MnO2 nanoneedles uniformly and the mass fraction of Pd in the Pd-coated α-MnO2 catalyst is about 8.88%. Compared with the counterpart of the hollow α-MnO2 catalyst, the hollow Pd-coated α-MnO2 catalyst improves the energy conversion efficiency and the charge-discharge cycling performance of the air electrode. The initial specific discharge capacity of an air electrode composed of Super P carbon and the as-prepared Pd-coatedα-MnO2 catalyst is 1220 mA＆#183;h/g （based on the total electrode mass） at a current density of 0.1 mA/cm2, and the capacity retention rate is about 47.3% after 13 charge-discharge cycles. The results of charge-discharge cycling tests demonstrate that this novel Pd-coatedα-MnO2 catalyst with a hierarchical core-shell structure is a promising catalyst for the lithium-air battery.

Design and Fabrication of Superparamaganitic Hybrid Microspheres for Protein Immobilization

Superparamagnetic poly（styrene）-co-poly（2-acrylanmido-2-methyl propanesulfonic acid） （PSt-co-PAMPS） and poly（methylmethacrylate）-co-poly（glycidyl methacrylate） （PMMA-co-PGMA） microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy （FT-IR） and transmission electron microscopy （TEM）. The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin （BSA） by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.

Crystal phase control and ignition properties of HNS/CL-20 composite microspheres prepared by microfluidics combined with emulsification techniques

Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the binder.The influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation performance.The results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size uniformity.The microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good dispersibility.The ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems.

Advances in controlled-release fertilizer encapsulated by organic-inorganic composite membranes

Heavy use of conventional fertilizers can lead to negative environmental concerns.Controlled-release fertilizers(CRFs)can effectively reduce the amounts of fertilizers used,improve the availability of fer-tilizers,and which is conducive to the protection of the ecological environment and sustainable devel-opment of agriculture.Therefore,it is imperative to develop and use CRFs as an alternative to traditional fertilizers.This review aims to present the classification,raw material composition,benefits,release process,release mode,and manufacturing methods of fertilizers coated with organic-inorganic com-posite membranes(OICMs)in order to provide an overall update and summarize CRFs encapsulated by OICMs and provide an insight for future trends in the field of fertilizers.It is expected that utilizing CRFs encapsulated by OICMs and their characteristics for agricultural applications can provide innovative ideas and suggestions for developing novel CRFs suitable for modern and sustainable agriculture.

Chondroitin Sulfate Fluorescence Biosensor Based on Graphere Quantum Dots Aggregating on CMC/CS Polyelectrolyte Microspheres

Here, we report an efficient fluorescence biosensor for chondroitin sulfate（CHS） based on polyelectrolyte microspheres of carboxymethyl cellulose（CMC） and chitosan（CS） composites inducing the aggregation of graphene quantum dots（GQDs）, calling CMC/CS-GQDs. The polyelectrolyte microspheres（CMC/CS microspheres） were fabricated by using anioniccationic electrostatic attraction between CMC and CS by high voltage electrostatic spray technology. The aggregating process of GQDs was based on the anionic-cationic electrostatic attraction as well. After combing with the polyelectrolyte microspheres, the fluorescence of GQDs disappeared. CHS, which widely consists in the cell surface of human beings and animals, carries a large number of negative charges on the surface. The addition of CHS enabled CHS and GQDs to compete with each other to composite with the CMC/CS microshpheres. As a result of the higher surface charge density of CHS, CMC/CS-CHS formed accompanied by the release of GQDs, and the fluorescence of the system recovered. The CHS content was detected by analyzing the system＇s fluorescence recovery, which suggested that the obtained fluorescence biosensor can accurately detect the concentration of CHS. The test results showed that the linear range of the fluorescence recovery for this biosensor with respect to CHS was 0~12.00 mg/mL, and the detection limit was 10-8 M. Besides, to test the stability of the biosensor, the CMC/CS-GQDs micropsheres persisted for one month, with a low fluorescence quenching of 9.48%. These results suggested that CMC/CS-GQDs can be utilized as efficient fluorescence biosensor for the detection of CHS. Moreover, the detection method was simple and efficient, and could be widely popularized.

Aqueous-Phase Sorption Behaviors of Cs⁺, Co²⁺, Sr²⁺and Cd²⁺ions on some Composite Ion Exchangers

A two new hybrid “organic-inorganic” composite ion exchangers (SAM and FAM), was synthesized by the combination of inorganic ion exchanger tin (IV) silicate and tin (IV) antimonate respectively with organic polymer polyacrylamide (PAm). The sorption isotherms for Cs+, Co2+, Sr2+ and Cd2+ ions on composite ion exchanger were investigated in the range (0.0005 - 0.01M) at different reaction temperature (30℃, 45℃ and 60℃ ± 1℃). The sorption data were subjected to different sorption isotherms and the results verified that Langmuir isotherm is the best model to be applied, and the monolayer sorption capacity were calculated and was found to increase as the reaction temperature increases.

基质细胞衍生因子1修饰左旋聚乳酸多孔微球促进软骨细胞增殖和组织形成

背景:二维培养条件下的软骨细胞增殖及表型维持受限,多孔微球作为支架材料可提供三维培养环境,以更好地模拟体内生长条件。基质细胞衍生因子1是有强趋化效力的稳态细胞因子,能够促进细胞的黏附与增殖。目的:明确接枝基质细胞衍生因子1左旋聚乳酸多孔微球对软骨细胞生物学特性及软骨组织形成的影响。方法:(1)体外验证不同质量浓度基质细胞衍生因子1对兔软骨细胞增殖、迁移、表型维持的影响。(2)采用复乳法制备左旋聚乳酸多孔微球,利用碳二亚胺法将基质细胞衍生因子1接枝于左旋聚乳酸多孔微球上,通过酶联免疫吸附实验及孵育基质细胞衍生因子1特异荧光抗体验证接枝情况。(3)将兔软骨细胞分别接种于左旋聚乳酸多孔微球、接枝基质细胞衍生因子1左旋聚乳酸多孔微球上,检测细胞增殖与黏附。(4)在裸鼠背部皮下分别植入甲基丙烯酰胺基明胶-软骨细胞复合体(对照组)、左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球组)、接枝基质细胞衍生因子1左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球修饰组),8周后取材,分别进行组织学染色与成软骨相关基因qRT-PCR检测。结果与结论:(1)相较于0,1 000 ng/mL基质细胞衍生因子1,500 ng/mL基质细胞衍生因子1可促进软骨细胞的增殖与迁移,提升软骨细胞内Ⅱ型胶原、弹性蛋白、增殖细胞核抗原、Bcl-2 mRNA表达;(2)基质细胞衍生因子1成功接枝于左旋聚乳酸多孔微球上,接枝率为93.75%;(3)相较于左旋聚乳酸多孔微球,接枝基质细胞衍生因子1左旋聚乳酸多孔微球可促进软骨细胞的增殖、黏附;(4)裸鼠皮下植入8周后,相较于对照组、多孔微球组,多孔微球修饰组具有更明显的软骨陷窝结构、更丰富的软骨特异性基质和Ⅱ型胶原沉积,弹性蛋白、Ⅱ型胶原、增殖细胞核抗原、Bcl-2 mRNA表达升高。结果表明:接枝基质细胞衍生因子1左旋聚乳酸多孔微球有利于软骨细胞的黏附、增殖、表型维持以及体内软骨组织形成。

Facile synthesis of hierarchical NiO/NiFe_(2)O_(4) microsphere composite as efficient visible photocatalyst for 2,4-DCP degradation

It is highly desired to develop efficient photocatalysts with recycling property for practical application to degrade toxic pollutants.Herein,nanosheet-assembled NiFe_(2)O_(4)microspheres with commendable activity are successfully synthesized by a facile solvothermal reaction with NH4F as the modifier,and their photoactivities are further improved by coupling with NiO through an in situ growth process.The optimized nickel oxide(NiO)/nickel ferrite(NiFe_(2)O_(4))microsphere composite(5NiO/NFO-4)exhibits a satisfactory photocatalytic activity for 2,4-dichlorophenol(2,4-DCP)degradation under visible-light irradiation,which is attributed to its wide visible-light response,well-designed hierarchical structure and enhanced charge transfer and separation by coupling NiO as a high-level energy platform to accept electrons.Moreover,it is found that the NiO/NiFe_(2)O_(4)microsphere photocatalysts can be easily collected and recycled owing to the distinctive magnetic properties.This work provides a feasible route to rational design visible-light-driven photocatalysts with high-activity for environmental remediation and purification with good recyclability.

PREPARATION OF COMPOSITE MAGNETIC MICROSPHERES BY REACTIVE BLENDING

A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe3O4 nanoparticles in PA6 domains of polystyrene （PS）/polyamide 6 （PA6） immiscible blends. The morphology of PA6/Fe3O4 composite magnetic mierospheres was studied by scanning electronic microscopy （SEM）. The composite magnetic mierospheres were spherical with a diameter range of 0.5-8 μm; the diameter was sharply decreased with a very narrow distribution by adding terminal maleic anhydride fimctionalized polystyrenes （FPS） for reactive blending. Transmission electron microscopy （TEM） and thermogravimetry analysis （TGA） results showed that most of Fe3O4 was located in the PA6 microspheres. Magnetization data revealed the magnetite content of PA6/Fe3O4 microspheres was about 32 wt% and the saturation magnetization could be up to 17.2 AmE/kg.