Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres supported palladium complex as an efficient catalyst for Heck reaction

Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres synthesized by suspension polymerization were used as supports for palladium catalyst.The results showed the novel magnetic catalyst can promote Heck reaction of aryl halides with acrylic acid efficiently without an inert atmosphere.In addition,the novel catalyst can be conveniently recovered by applying an external magnet and reused at least five times without significant loss of its activity.

Effect of particle size on the preparation and microwave absorption properties of FeSiAl magnetically soft alloy hollow microspheres

FeSiAl magnetically soft alloy hollow microspheres(MSAHMs) were prepared by self-reactive quenching technology based on Fe + Si + AI + KNO_3 reactive systems, in order to obtain absorbents with light weight, low frequency and high efficiency. Firstly, twice-balling adhesive precursor method was used to obtain FeSiAl magnetically soft alloy agglomerate powders. Then agglomerate powders with the mesh number of 150-240, 240-325 and 325-400 were sprayed through the flame field into the quenching water. At last, FeSiAl MSAHMs with coarse(average at 86.97 μm), medium(average at 52.16 μm) and fine particles(average at 31.80 μm) were got. Effect of particle size on the phases and microwave absorption properties in low frequency band was studied by XRD and vector network analyzer. The results show that,Fe_3 Si_(0.7)Al_(0.3) and Fe_3 Si_(0.5)Al_(0.5) appear in the phase components of FeSiAl MSAHMs,which is important to improve the microwave absorption properties in low frequency. In addition, the real part(ε′) and imaginary part(ε″) of complex permittivity, the real part(μ′) and imaginary part(μ″) of complex permeability of FeSiAl MSAHMs all present the trend of fine particles > medium particles > coarse particles. The microwave absorption properties in low frequency are improved with the increasing of particle size, and the absorption peak moves to lower frequency range. The properties of fine particles are the best. Their matching thickness of samples is at 5 mm, and the minimum reflectivity is-43 dB at this thickness. The absorption frequency band lower than-10 dB is 4.6-7.6 GHz with a bandwidth of 3 GHz.

Preparation of Adriamycin Magnetic Albumin Microspheres and Their Experimental Antitumor Effects in vitro and in vivo

The adriamycin magnetic microspheres (ADM-MAMs) were prepared by the heat-stabilized protein methods. Their physico-chemical properties were examined; their cytotoxicities against tumor cells in vitro were assayed by a modi-fied MTT method, and their effects were observed on the implanted gastric tumor in Wistar rats given ADM-MAMs via alimentary canal at the presence of the ex-ternal magnetic fields. The results showed that the ADM-MAMs were successful-ly prepared and had cytotoxic effect on tumor cells in vitro similar to the free ADM (P>0. 05). The inhibitory effects of ADM-MAMs on the implanted gastric tumor in vivo were significantly increased as compared with the controls (P<0.01). Our results suggested that ADM-MAMs were a new type of adriamycin (ADM) preparation and its form alteration did not affect its anticancer effects.

Preparation and in vitro Release Properties of Mercaptopurine Drug-loaded Magnetic Microspheres

Magnetic Fe304 nanoparticles were synthesized by co-precipitation method and the mercaptopurine （MER） drug-loaded magnetic microspheres were obtained through emulsion cross-linking methods. The efficiency of this approach was evaluated in terms of drug loading content （DLC）, encapsulation efficiency （EE） and delivery properties in vitro, determined by high performance liquid chromatograph （HPLC）. The microspheres showed good DLC values of 11.8%, as well as good EE values of 79.4%. The in vitro drug release study was carried out in phosphate buffer solution （PBS） simulated body fluid, at 37 ~C with pH=7.4. The release profiles showed an initial fast release rate, which decreased as time progressed and about 84 % had been released after 48 h. The experimental results indicated that the prepared magnetic microspheres may be useful for potential applications of MER for magnetically targeted chemotherapy.

Mechanically activated starch magnetic microspheres for Cd(Ⅱ)adsorption from aqueous solution

Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft copolymer monomers,and methyl methacrylate(MMA)as the dispersing agent and used as an adsorbent for the removal of Cd(Ⅱ)ions from aqueous solution.Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and vibrating sample magnetometry(VSM)were used to characterize the AAM-MSM adsorbent.The results indicated that AA,AM,and MMA were grafted to the MS,and the Fe_(3)O_(4) nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres.The adsorbent exhibited a smooth surface,uniform size,and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(Ⅱ)ions.The maximum adsorption capacity of Cd(Ⅱ)on the AAM-MSM was 39.98 mg·g^(-1).The adsorbents were superparamagnetic,and the saturation magnetization was 16.7 A·m^(2)·kg^(-1).Additionally,the adsorption isotherms and kinetics of the adsorption process were further investigated.The process of Cd(Ⅱ)ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models,which suggested that the chemical reaction process dominated the adsorption process for the Cd(Ⅱ)and chemisorption was the rate-controlling step during the Cd(Ⅱ)removal process.

A Modified Method for Preparation of Adriamycin Carried by Magnetic Albumin Microspheres

The targeting of antineoplastic agents to restricted anatomic sites and specific target cells have been challenged clinicians all the time in cancer chemotherapy, which resulted in recent efforts to focus the effects of existing antitumor agents and treatments on tumor cells and spare their effects on normal cells. The drug-carrier complex, adriamycin carried by magnetic albumin microspheres (ADM-MAM) was prepared by using our discovered new and modified method. The physical feature of the prepared drug-carrier microspheres was much better than by the traditional method in comparison. The successful preparation of the drug-carrier complex, ADM-MAM, is one of the key steps for our later further researches in the targeted chemotherapy.

Preparation of magnetic gelatin-starch microspheres and adsorption performance for bovine serum album

The magnetic gelatin-starch microspheres were prepared by modified emulsion cross-linking method with glutaraldehyde as the cross-linking agent. The structure, size distribution as well as morphology of magnetic microspheres were investigated by FT-IR spectrometer, dynamic laser scattering analyzer and scanning electron microscope, respectively. Bovine serum album(BSA)was chosen as model protein, and the adsorption processes were carried out under diversified conditions including BSA initial concentration, p H value, adsorption time and temperature to evaluate the performance of the magnetic microspheres. The average diameter of optimized spherical magnetic microspheres is 1.6 μm with excellent dispersivity, and the saturation magnetization is found to be equal to 1.056×10-2 A·m2. The adsorption isotherm of the BSA on the magnetic microspheres basically obeys the Langmuir model, with a maximum adsorption capacity of 120 mg/g and an adsorption equilibrium constant of 1.60 mL/mg.

Preparation and Characterization of Non-porous Superparamagnetic Microspheres with Epoxy Groups by Dispersion Polymerization

Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2’-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of-1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu.g-1. There was abundance of epoxy groups with density of 0.028 mmol·g^-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology.

Magnetic Fe3O4@mTiO2-AIPA Microspheres for Separation of Phosphoproteins and Non-phosphoproteins

A novel phosphoprotein separation material was developed, which is constructed by a magnetic mesoporous Fe3O4@TiO2 (Fe3O4@mTiO2) microsphere and a 5-aminoisophthalic acid (AIPA) monolayer that provides additional binding sites toward phosphate groups. The results of characteristic experiments demonstrated that Fe3O4@mTiO2-AIPA had good dispersability, high magnetic susceptibility, and satisfactory grafting ratio of AIPA, ascribed to the large specific surface area of the inorganic substrate. Taking advantages of these features, Fe3O4@mTiO2-AIPA was successfully utilized to separate a-casein (a typical phosphoprotein) and bovine serum albumin (BSA, a typical non-phosphoprotein) from their mixtures (molar ratio = 1:2). Through adjusting pH and polarity of solutions, the BSA and a-casein were respectively enriched in washing fraction and elution fraction. This result displays the good potential of Fe3O4@mTiO2-AIPA for application in phosphoprotein enrichment.

Characterization of Fe_3O_4/P(St-MPEO) Amphiphilic Magnetic Polymer Microspheres

Amphiphilic magnetic microspheres consisting of styrene and poly(ethylene oxide) macromonomer(MPEO) were prepared by dispersion copolymerization in the presence of Fe_3O_4 magnetic fluid in an ethanol/water medium. The sizes of the magnetic microspheres and their distribution were characterized by means of scanning electron microscopy(SEM). The surface morphology and the average surface roughness of the microspheres were investigated by virtue of atomic force microscopy(AFM). It was found that the microspheres exhibit microscopic phase-separate and the mean square surface roughness of the microspheres increases with increasing MPEO used in the copolymerization. The amphiphilic magnetic microspheres containing 0 4-3 5 mg/g hydroxyl groups could be prepared from MPEO with different concentrations and styrene.

Toxicity of Magnetic Albumin Microspheres Bearing Adriamycin

Magnetic albumin microspheres bearing adriamycin (ADM MAM) is a novel chemotherapeutic compound with site specific drug delivery characteristics. The acute and subacute toxic tests of the compound, local irritating test and anaphylactic test were performed on mice and guinea pigs. The results showed there was no macroscopically and microscopically direct cytotoxic injuries of the compound to the animal organs or to the cells. The LD 50 value of the compound was higher than that of the single used adriamycin, indicating that the compound was less toxic than the single adriamycin and quite safe in its therapeutic dosage. Furthermore, there was also no side effects or toxic reactions to be observed on clinical patients with advanced carcinoma or gastric cancer.

Preparation of biocompatible magnetic microspheres with chitosan

Microsphere is a term used for small spherical particles, with diameters in the micrometer range (typically 1μm to 1000μm (1mm)). Microspheres are sometimes referred to as microparticles. Microspheres can be manufactured from various natural and synthetic materials. The present work we prepared chitosan magnetic microspheres (CMMS) with simple crosslinking method. The obtained CMMS were in size range of 1000-2600 nm with average particle size of 1800nm. All the essential characterizations of prepared CMMS were done and the results were in a good agreement with other magnetic microspheres prepared with different method. To test the biocompatibility of CMMS with blood, the effect of them on erythrocytes aggregation and blood hemolysis were studied. Our results showed that CMMS work as good compatible materials with blood.

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.

Study on Magnetic Responsibility of Rare Earth Ferrite/Polyacrylamide Magnetic Microsphere

In inverse microemulsion, rare earth ferrite/polyacrylamide magnetic microsphere were prepared and their magnetic responsibility were studied by magnetic balance. Results indicate that the magnetic responsibility of microsphere relates to magnetic moment of rare earth ion, and it can be improved by the addition of dysprosium ion of high magnetic moment. Dysprosium content has an effect on magnetic responsibility of dysprosium ferrite/polyacrylamide magnetic microsphere. The microsphere displays strong magnetic responsibility when the molar ratio of Dy3+/iron is 0.20.

MOFs‑Derived Strategy and Ternary Alloys Regulation in Flower‑Like Magnetic‑Carbon Microspheres with Broadband Electromagnetic Wave Absorption

Broadband electromagnetic(EM)wave absorption materials play an important role in military stealth and health protection.Herein,metal–organic frameworks(MOFs)-derived magnetic-carbon CoNiM@C(M=Cu,Zn,Fe,Mn)microspheres are fabricated,which exhibit flower-like nano–microstructure with tunable EM response capacity.Based on the MOFs-derived CoNi@C microsphere,the adjacent third element is introduced into magnetic CoNi alloy to enhance EM wave absorption performance.In term of broadband absorption,the order of efficient absorption bandwidth(EAB)value is Mn>Fe=Zn>Cu in the CoNiM@C microspheres.Therefore,MOFs-derived flower-like CoNiMn@C microspheres hold outstanding broadband absorption and the EAB can reach up to 5.8 GHz(covering 12.2–18 GHz at 2.0 mm thickness).Besides,off-axis electron holography and computational simulations are applied to elucidate the inherent dielectric dissipation and magnetic loss.Rich heterointerfaces in CoNiMn@C promote the aggregation of the negative/positive charges at the contacting region,forming interfacial polarization.The graphitized carbon layer catalyzed by the magnetic CoNiMn core offered the electron mobility path,boosting the conductive loss.Equally importantly,magnetic coupling is observed in the CoNiMn@C to strengthen the magnetic responding behaviors.This study provides a new guide to build broadband EM absorption by regulating the ternary magnetic alloy.

An efficient synthesis of ampicillin on magnetically separable immobilized penicillin G acylase

Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g.The 96.7%ampicillin yield with 1.60 of the synthesis/hydrolysis(S/H) ratio from 6-aminopenicillanic acid(6-APA) and D-(-)-alpha-phenylglycine methyl ester(D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol,where only 82.1%yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions.The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.

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.

Porous TiO2-coated Magnetic Core-Shell Nanocomposites：Preparation and Enhanced Photocatalytic Activity

核心壳组织了 TiO2/SiO2@Fe3O4 光催化剂作为磁性的核心用 Fe3O4 被准备， tetraethoxysilane (TEOS ) 作为钛作为硅石来源和 tetrabutyl titanate (TBOT ) 采购原料。同样获得的结构由一个 SiO2@Fe3O4 核心和多孔的 TiO2 壳组成。SiO2@Fe3O4 核心的直径是有大约 5-6 nm 的多孔的 TiO2 的厚度的大约 205 nm。9%TiO2/6% SiO2@Fe3O4 microspheres 拥有最高的赌注表面区域和 BJH 毛孔体积，它是 373.5 m2as 2436

Fabrication of magnetically recyclable yolk-shell Fe_(3)O_(4)@TiO_(2) nanosheet/Ag/g-C_(3)N_(4) microspheres for enhanced photocatalytic degradation of organic pollutants

Herein,we report the fabrication of Fe_(3)O_(4)@TiO_(2) nanosheet/Ag/g-C_(3)N_(4)(Fe_(3)O_(4)@ns-TiO_(2)/Ag/g-C_(3)N_(4))composite photocatalysts with well-designed hierarchical yolk-shell structure.To endow the composites with fascinating features,multiple functional components are perfectly integrated into the definite structure.The photodegradation experiments of organic pollutants revealed a significant enhancement in photocatalytic activity of developed composites as compared to P25,which is mainly due to the synergetic interaction of the tailored three-dimensional(3D)yolk-shell porous nanostructure,extended sunlight response range,and retarded the recombination probability of photogenerated electrons-holes.More importantly,the hybrid samples exhibited superior magnetic properties due to the magnetic component.The excellent magnetic recyclability and reusability of the photocatalysts are verified by the magnetic hysteresis loop and cyclic photocatalytic degradation experiments,which is significant for the green and sustainable applications of photocatalysts.Considering its remarkable photocatalytic performance and expectant magnetic recyclability,the composite photocatalysts are expected to be a promising candidate to dispose of future environmental issues.

Magnetic yolk-shell structured anatase-based microspheres loaded with Au nanoparticles for heterogeneous catalysis

磁性的蛋黄壳组织了基于锐钛矿的 microspheres 在磁铁矿粒子上通过连续、灵巧的大音阶的第五音胶化涂层被制作，由退火列在后面处理。在与金 nanoparticles 装载之上，获得的功能的磁性的 microspheres 在向苯乙烯氧化物与非凡的高变换(89.5%) 和选择(90.8%) 催化苯乙烯的 epoxidation 作为异构的催化剂显示出优异性能。这些迷人的材料的构造过程为创造另外的功能的 nanocomposites 展示许多含意，这被相信。