WorldWideScience

Sample records for large porous microspheres

  1. Preparation and characterization of monodisperse large-porous silica microspheres as the matrix for protein separation.

    Science.gov (United States)

    Xia, Hongjun; Wan, Guangping; Zhao, Junlong; Liu, Jiawei; Bai, Quan

    2016-11-04

    High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (PGMA-EDMA) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species. Then the low molecular weight species diffused into the functionalized PGMA-EDMA microspheres by induction force of the amino groups to form polymer/silica hybrid microspheres. Finally, the organic polymer templates were removed by calcination, and the large-porous silica microspheres were obtained. The compositions, morphology, size distribution, specific surface area and pore size distribution of the porous silica microspheres were characterized by infrared analyzer, scanning-electron microscopy, dynamic laser scattering, the mercury intrusion method and thermal gravimetric analysis, respectively. The results show that the agglomeration of the hybrid microspheres can be overcome when the templates were functionalized with TEPA as amination reagent, and the yield of 95.7% of the monodisperse large-porous silica microspheres can be achieved with high concentration of polymer templates. The resulting large-porous silica microspheres were modified with octadecyltrichlorosilane (ODS) and the chromatographic evaluation was performed by separating the proteins and the digest of BSA. The baseline separation of seven kinds of protein standards was achieved, and the column delivered a better performance when separating BSA digests

  2. Porous microsphere and its applications

    Directory of Open Access Journals (Sweden)

    Cai Y

    2013-03-01

    Full Text Available Yunpeng Cai,1,2* Yinghui Chen,3* Xiaoyun Hong,2 Zhenguo Liu,1 Weien Yuan2 1Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 2School of Pharmacy, Shanghai JiaoTong University, 3Department of Neurology Jinshan Hospital, Fudan University, Shanghai, People's Republic of China *These authors contributed equally to this workAbstract: Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies.Keywords: pore, porosity, porogen, suspension polymerization, seed swelling, pulmonary drug delivery, tissue regeneration

  3. POROUS WALL, HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to &apos

  4. Microwave Assisted Synthesis of Porous NiCo2O4 Microspheres: Application as High Performance Asymmetric and Symmetric Supercapacitors with Large Areal Capacitance

    Science.gov (United States)

    Khalid, Syed; Cao, Chuanbao; Wang, Lin; Zhu, Youqi

    2016-03-01

    Large areal capacitance is essentially required to integrate the energy storage devices at the microscale electronic appliances. Energy storage devices based on metal oxides are mostly fabricated with low mass loading per unit area which demonstrated low areal capacitance. It is still a challenge to fabricate supercapacitor devices of porous metal oxides with large areal capacitance. Herein we report microwave method followed by a pyrolysis of the as-prepared precursor is used to synthesize porous nickel cobaltite microspheres. Porous NiCo2O4 microspheres are capable to deliver large areal capacitance due to their high specific surface area and small crystallite size. The facile strategy is successfully demonstrated to fabricate aqueous-based asymmetric & symmetric supercapacitor devices of porous NiCo2O4 microspheres with high mass loading of electroactive materials. The asymmetric & symmetric devices exhibit maximum areal capacitance and energy density of 380 mF cm‑2 & 19.1 Wh Kg‑1 and 194 mF cm‑2 & 4.5 Wh Kg‑1 (based on total mass loading of 6.25 & 6.0 mg) respectively at current density of 1 mA cm‑2. The successful fabrication of symmetric device also indicates that NiCo2O4 can also be used as the negative electrode material for futuristic asymmetric devices.

  5. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  6. Hollow porous-wall glass microspheres for hydrogen storage

    Science.gov (United States)

    Heung, Leung K.; Schumacher, Ray F.; Wicks, George G.

    2010-02-23

    A porous wall hollow glass microsphere is provided having a diameter range of between 1 to 200 microns, a density of between 1.0 to 2.0 gm/cc, a porous-wall structure having wall openings defining an average pore size of between 10 to 1000 angstroms, and which contains therein a hydrogen storage material. The porous-wall structure facilitates the introduction of a hydrogen storage material into the interior of the porous wall hollow glass microsphere. In this manner, the resulting hollow glass microsphere can provide a membrane for the selective transport of hydrogen through the porous walls of the microsphere, the small pore size preventing gaseous or liquid contaminants from entering the interior of the hollow glass microsphere.

  7. Porous-wall hollow glass microspheres as carriers for biomolecules

    Science.gov (United States)

    Li, Shuyi; Dynan, William S; Wicks, George; Serkiz, Steven

    2013-09-17

    The present invention includes compositions of porous-wall hollow glass microspheres and one or more biomolecules, wherein the one or more biomolecules are positioned within a void location within the hollow glass microsphere, and the use of such compositions for the diagnostic and/or therapeutic delivery of biomolecules.

  8. Preparation of Hollow Porous HAP Microspheres as Drug Delivery Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Qing; HUANG Wenhai; WANG Deping

    2007-01-01

    Hollow HAP microspheres in sub-millimeter size were prepared and investigated as a drug delivery vehicle. The LCB (lithium-calcium borate) glass microspheres, which were made through flame spray process, were chosen as precursor for hollow HAP microspheres. The LCB glass microspheres reacted with phosphate buffer (K2HPO4) solution for 5 days at 37 ℃. During the reaction the Ca-P-OH compound precipitated on the surface of LCB glass microspheres and formed porous shells. Then the microspheres turned to be hollow ones with the same diameter as the glass microspheres after LCB glass run out in the chemical reaction. After heat-treated at 600 ℃ for 4 h, the Ca-P-OH compound became HAP, thus the hollow HAP microspheres were produced. The mechanism of forming hollow HAP microspheres through the chemical reaction between phosphate buffer and LCB glass was confirmed by the XRD analysis. The microstructure characteristics of the hollow, porous microspheres were observed by SEM.

  9. Synthesis and characterization of porous microspheres bearing pyrrolidone units

    Energy Technology Data Exchange (ETDEWEB)

    Maciejewska, M., E-mail: mmacieje@umcs.pl; Kołodyńska, D.

    2015-01-15

    Porous microspheres of glycydyl methacrylate (GMA) cross-linked with trimethylolpropane trimethacrylate (TRIM) were prepared with toluene as porogen by suspension-emulsion polymerization. With increasing molar ratio of the functional monomer to cross-linker, the epoxy group content increases significantly whereas the parameters of porous structure (specific surface area and total pore volume) decreases. In order to obtain adsorbents bearing functional groups the porous methacrylate network was modified by subsequent reaction with pyrrolidone. The materials were studied using elemental analysis, infrared spectroscopy, atomic force microscopy (AFM), attenuated total reflection (ATR) spectroscopy, Raman spectroscopy, thermal gravimetry. Additionally, polymers sorption capacity towards Cu(II) was investigated. - Highlights: • Porous microspheres with reactive epoxy group were synthesized. • Highly developed porous structure was created. • Pyrrolidone units were incorporated during ring–opening reaction. • Polymers sorption capacity towards Cu (II) was investigated.

  10. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

    Picart, S.; Parant, P.; Caisso, M.; Remy, E.; Mokhtari, H.; Jobelin, I.; Bayle, J. P.; Martin, C. L.; Blanchart, P.; Ayral, A.; Delahaye, T.

    2015-07-01

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of flowability for the filling of compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 °C and temperature rate lower than 2 °C/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density (TD) and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner.

  11. Controlled Synthesis of Hierarchically Assembled Porous ZnO Microspheres with Enhanced Gas-Sensing Properties

    Directory of Open Access Journals (Sweden)

    Shengsheng You

    2015-01-01

    Full Text Available The ZnO microspheres constructed by porous nanosheets were successfully synthesized by calcinating zinc hydroxide carbonate (ZHC microspheres obtained by a sample hydrothermal method. The samples were characterized in detail with scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and thermogravimetric and differential scanning calorimetry (TG-DSC. The results indicated that the prepared ZnO microspheres were well crystalline with wurtzite hexagonal phase. The effects of reaction time, temperature, the amount of trisodium citrate, and urea on the morphology of ZnO microspheres were studied. The formation mechanism of porous ZnO microspheres was discussed. Furthermore, the gas-sensing properties for detection of organic gas of the prepared porous ZnO microspheres were investigated. The results indicated that the prepared porous ZnO microspheres exhibited high gas-sensing properties for detection of ethanol gas.

  12. A novel strategy for the preparation of porous microspheres and its application in peptide drug loading.

    Science.gov (United States)

    Wei, Yi; Wang, Yuxia; Zhang, Huixia; Zhou, Weiqing; Ma, Guanghui

    2016-09-15

    A new strategy is developed to prepare porous microspheres with narrow size distribution for peptides controlled release, involving a fabrication of porous microspheres without any porogens followed by a pore closing process. Amphiphilic polymers with different hydrophobic segments (poly(monomethoxypolyethylene glycol-co-d,l-lactide) (mPEG-PLA), poly(monomethoxypolyethylene glycol-co-d,l-lactic-co-glycolic acid) (mPEG-PLGA)) are employed as microspheres matrix to prepare porous microspheres based on a double emulsion-premix membrane emulsification technique combined with a solvent evaporation method. Both microspheres possess narrow size distribution and porous surface, which are mainly caused by (a) hydrophilic polyethylene glycol (PEG) segments absorbing water molecules followed by a water evaporation process and (b) local explosion of microspheres due to fast evaporation of dichloromethane (MC). Importantly, mPEG-PLGA microspheres have a honeycomb like structure while mPEG-PLA microspheres have a solid structure internally, illustrating that the different hydrophobic segments could modulate the affinity between solvent and matrix polymer and influence the phase separation rate of microspheres matrix. Long term release patterns are demonstrated with pore-closed microspheres, which are prepared from mPEG-PLGA microspheres loading salmon calcitonin (SCT). These results suggest that it is potential to construct porous microspheres for drug sustained release using permanent geometric templates as new porogens.

  13. Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater.

    Science.gov (United States)

    Liu, Qingquan; Wang, Li; Xiao, Anguo; Gao, Jingming; Ding, Wenbing; Yu, Haojie; Huo, Jia; Ericson, Mårten

    2010-09-15

    Porous magnetic microspheres with large particle size (350-450 microm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe(3)O(4)). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Fabrication and characterization of porous hydroxyapatite microspheres by spray-drying method

    Institute of Scientific and Technical Information of China (English)

    Rui-xue SUN; Yu-peng LU

    2008-01-01

    In the present paper, porous hydroxyapatite (HA) microspheres were fabricated using gelatin as a pore-forming agent by spray-drying method. The mean particle size of the microspheres is about 7 μm and the surface area is about 53.4 m2/g. The experimental results showed that the porosity of the prepared microspheres is higher and the pores are more interconnected compared with the microspheres obtained without any additives.

  15. Acrolein Microspheres Are Bonded To Large-Area Substrates

    Science.gov (United States)

    Rembaum, Alan; Yen, Richard C. K.

    1988-01-01

    Reactive cross-linked microspheres produced under influence of ionizing radiation in aqueous solutions of unsaturated aldehydes, such as acrolein, with sodium dodecyl sulfate. Diameters of spheres depend on concentrations of ingredients. If polystyrene, polymethylmethacrylate, or polypropylene object immersed in solution during irradiation, microspheres become attached to surface. Resulting modified surface has grainy coating with reactivity similar to free microspheres. Aldehyde-substituted-functional microspheres react under mild conditions with number of organic reagents and with most proteins. Microsphere-coated macrospheres or films used to immobilize high concentrations of proteins, enzymes, hormones, viruses, cells, and large number of organic compounds. Applications include separation techniques, clinical diagnostic tests, catalytic processes, and battery separators.

  16. Preparation and characterization of porous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride nanocomposite microspheres

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Mesoporous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride [P(St-DVB)/MA] nanocomposite microspheres were prepared by an open ring reaction method.The titania nanoparticles were first modified by attachment of amino groups to their surface to prevent particle aggregation,and to allow the nanoparticles to covalently bond the polymer microspheres,the surface of which was modified by attachment of MA functional groups to enable the polymer to retain their porous structures and to react with the amino groups on the surface of the titania particles.The porous nanocomposite microspheres were detected by FTIR,SEM,TEM,XRD and UV-Vis spectrophotometry.The results indicated that the nanocomposite microspheres were composed of nanosized titania uniformly distributed on the surface,and exhibited better UV absorbing property than pure polymer microspheres or unmodified titania.Furthermore,compared with pure porous polymer microspheres,the nanocomposite microspheres showed more efficient UV protection and slow release of Parsol-1789(a photo-reactive and cosmetic agent) held inside the porous network of the microspheres.

  17. Hierarchical porous microspheres of the Co3O4@graphene with enhanced electrocatalytic performance for electrochemical biosensors.

    Science.gov (United States)

    Yang, MinHo; Jeong, Jae-Min; Lee, Kyoung G; Kim, Do Hyun; Lee, Seok Jae; Choi, Bong Gill

    2017-03-15

    The integration of organic and inorganic building blocks into hierarchical porous architectures makes potentially desirable electrocatalytic materials in many electrochemical applications due to their combination of attractive qualities of dissimilar components and well-constructed charge transfer pathways. Herein, we demonstrate the preparation of the hierarchical porous Co3O4@graphene (Co3O4@G) microspheres by one-step hydrothermal method to achieve high electrocatalytic performance for enzyme-free biosensor applications. The obtained Co3O4@G microspheres are consisted of the interconnected networks of Co3O4 and graphene sheets, and thus provide large accessible active sites through porous structure, while graphene sheets offer continuous electron pathways for efficient electrocatalytic reaction of Co3O4. These structural merits with synergy effect of Co3O4 and graphene lead to a high performance of enzyme-free detection for glucose: high sensitivity, good selectivity, and remarkable stability.

  18. Structure design and fabrication of porous hydroxyapatite microspheres for cell delivery

    Science.gov (United States)

    Li, Ruijing; Chen, Kexin; Li, Geng; Han, Guoxiang; Yu, Sheng; Yao, Juming; Cai, Yurong

    2016-09-01

    Porous microspheres fabricated from bioceramics have great potential for cell delivery in injectable tissue engineering application. The size and structure of pores in the microspheres are important for the effective protection and transportation of cells. In this study, porous hydroxyapatite microspheres are fabricated through the water-in-oil emulsion method followed by a calcination treatment at the high temperature. Both self-made resorcinol-formaldehyde (RF) composite spheres and camphene are used as pore-forming agents to produce big pores corresponding to the size of RF spheres and connected channel among big pores in hydroxyapatite matrix. The properties of the microspheres are characterized using X-ray diffraction, thermogravimetry analysis, universal material machine, field emission scanning electron microscopy. Cell assays are carried out to evaluate the cellular compatibility of the microspheres. The results showed that the hydroxyapatite microspheres with controllable pore structure and high porosity could be fabricated by this method, which have better strength to resist the compressive force. The microspheres are conducive to support adhesion, proliferation and differentiation of MC3T3-E1 cells. The results indicate that the obtained porous hydroxyapatite microspheres can be a permeable microenvironment for cell delivery in injectable tissue engineering.

  19. Microspheres

    Science.gov (United States)

    1990-01-01

    Vital information on a person's physical condition can be obtained by identifying and counting the population of T-cells and B-cells, lymphocytes of the same shape and size that help the immune system protect the body from the invasion of disease. The late Dr. Alan Rembaum developed a method for identifying the cells. The method involved tagging the T-cells and B-cells with microspheres of different fluorescent color. Microspheres, which have fluorescent dye embedded in them, are chemically treated so that they can link with antibodies. With the help of a complex antibody/antigen reaction, the microspheres bind themselves to specific 'targets,' in this case the T-cells or B-cells. Each group of cells can then be analyzed by a photoelectronic instrument at different wavelengths emitted by the fluorescent dyes. Same concept was applied to the separation of cancer cells from normal cells. Microspheres were also used to conduct many other research projects. Under a patent license Magsphere, Inc. is producing a wide spectrum of microspheres on a large scale and selling them worldwide for various applications.

  20. Porous wall hollow glass microspheres as a medium or substrate for storage and formation of novel materials

    Science.gov (United States)

    Wicks, George G; Serkiz, Steven M.; Zidan, Ragaiy; Heung, Leung K.

    2014-06-24

    Porous wall hollow glass microspheres are provided as a template for formation of nanostructures such as carbon nanotubes, In addition, the carbon nanotubes in combination with the porous wall hollow glass microsphere provides an additional reaction template with respect to carbon nanotubes.

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

    Institute of Scientific and Technical Information of China (English)

    马志亚; 官月平; 刘先桥; 刘会洲

    2005-01-01

    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.

  2. Drastic difference in porous structure of calcium alginate microspheres prepared with fresh or hydrolyzed sodium alginate.

    Science.gov (United States)

    Akamatsu, Kazuki; Maruyama, Kaho; Chen, Wei; Nakao, Aiko; Nakao, Shin-ichi

    2011-11-15

    Fresh or hydrolyzed sodium alginate was used as a material for preparing calcium alginate microspheres, and a drastic difference in porous structure was observed between them, even though the other materials and the preparation method except for the sodium alginate were exactly the same. When fresh sodium alginate was used, nonporous microspheres were obtained. In contrast, when 82-day-hydrolyzed sodium alginate, whose molecular weight became 7% of the molecular weight of the fresh sodium alginate, was used, porous microspheres with 6.5 times larger BET surface area were obtained. XPS studies indicated that the atomic ratio of Ca, the crosslinker of the alginic acid polymer, was almost the same in both cases. Therefore, the difference in porous structure was not attributed to the amount of crosslinking points, but to the low-molecular-weight compounds formed by hydrolysis, and they would work as pore-generating agents. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Preparation of magnetic hierarchically porous microspheres with temperature-controlled wettability for removal of oils.

    Science.gov (United States)

    Tao, Shengyang; Ding, Yunzhe; Jiang, Lei; Li, Guangtao

    2017-04-15

    A series of monodispersed microspheres with hierarchically porous structures were prepared by microfluidic devices. Phase separation of the silica sol in microdroplets was adopted to construct these structures. The effects of velocity ratios (for both the continuous and the dispersed phases), collection solvents and calcination temperatures were investigated. The diameters of the microspheres were tuned from 148μm to 940μm by adjusting the velocity ratio. Tests revealed that the surface areas and pore volumes of the microspheres can reach 495m(2)g(-1) and 0.6068mlg(-1), respectively. The macroporous structure can be controlled by the collection solvents, and the wettability of the microspheres is determined by the calcination temperature. A calcination temperature of 450°C leads to a hydrophilic surface property. Fe3O4 nanoparticles were added to the silica sol to form magnetic microspheres, and the porous structure was not affected. This kind of hybrid microsphere adsorbs 3.29 times its own weight in toluene. These spheres can adsorb oil on water surfaces, and then be removed from the water with an external magnetic field. The microspheres can be recovered and reused more than 10 times. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Investigation on efficient adsorption of cationic dyes on porous magnetic polyacrylamide microspheres.

    Science.gov (United States)

    Yao, Tong; Guo, Song; Zeng, Changfeng; Wang, Chongqing; Zhang, Lixiong

    2015-07-15

    We report here the preparation of porous magnetic polyacrylamide microspheres for efficient removal of cationic dyes by a simple polymerization-induced phase separation method. Characterizations by various techniques indicate that the microspheres show porous structures and magnetic properties. They can adsorb methylene blue with high efficiency, with adsorption capacity increasing from 263 to 1977 mg/g as the initial concentration increases from 5 to 300 mg/L. Complete removal of methylene blue can be obtained even at very low concentrations. The equilibrium data is well described by the Langmuir isotherm models, exhibiting a maximum adsorption capacity of 1990 mg/g. The adsorption capacity increases with increasing initial pH and reaches a maximum at pH 8, revealing an electrostatic interaction between the microspheres and the methylene blue molecules. The microspheres also show high adsorption capacities for neutral red and gentian violet of 1937 and 1850 mg/g, respectively, as well as high efficiency in adsorption of mixed-dye solutions. The dye-adsorbed magnetic polyacrylamide microspheres can be easily desorbed, and can be repeatedly used for at least 6 cycles without losing the adsorption capacity. The adsorption capacity and efficiency of the microspheres are much higher than those of reported adsorbents, which exhibits potential practical application in removing cationic dyes.

  5. Release of PLGA–encapsulated dexamethasone from microsphere loaded porous surfaces

    NARCIS (Netherlands)

    Dawes, G.J.S.; Fratila-Apachitei, L.E.; Necula, B.S.; Apachitei, I.; Witkamp, G.J.; Duszczyk, J.

    2009-01-01

    The aim of the present study was to investigate the morphology and function of a drug eluting metallic porous surface produced by the immobilization of poly lactide-co-glycolide microspheres bearing dexamethasone onto plasma electrolytically oxidized Ti–6Al–7Nb medical alloy. Spheres of 20 µm diamet

  6. Preparation of porous microsphere-scaffolds by electrohydrodynamic forming and thermally induced phase separation

    Energy Technology Data Exchange (ETDEWEB)

    Ghanbar, Hanif; Luo, C.J.; Bakhshi, Poonam [Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Day, Richard [Division of Medicine, University College London, Rockefeller Building, 21 University Street, London, WC1E 6JJ (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

    2013-07-01

    The availability of forming technologies able to mass produce porous polymeric microspheres with diameters ranging from 150 to 300 μm is significant for some biomedical applications where tissue augmentation is required. Moreover, appropriate assembly of microspheres into scaffolds is an important challenge to enable direct usage of the as-formed structures in treatments. This work reports the production of poly (glycolic-co-lactic acid) and poly (ε-caprolactone) microspheres under ambient conditions using one-step electrohydrodynamic jetting (traditionally known as atomisation) and thermally induced phase separation (TIPS). To ensure robust production for practical uses, this work presents 12 comprehensive parametric mode mappings of the diameter distribution profiles of the microspheres obtained over a broad range of key processing parameters and correlating of this with the material parameters of 5 different polymer solutions of various concentrations. Poly (glycolic-co-lactic acid) (PLGA) in Dimethyl carbonate (DMC), a low toxicity solvent with moderate conductivity and low dielectric constant, generated microspheres within the targeted diameter range of 150–300 μm. The fabrication of the microspheres suitable for formation of the scaffold structure is achieved by changing the collection method from distilled water to liquid nitrogen and lyophilisation in a freeze dryer. Highlights: ► EHDA is a unique method for production of the desired size of microspheres. ► Polymer solution properties are used to tailor the size distribution of spheres. ► Process control parameters (flow rate and applied voltage) are key in size control. ► Combination of EHDA with TIPS provides porous microspheres for assembly of scaffold.

  7. Porous titania/carbon hybrid microspheres templated by in situ formed polystyrene colloids.

    Science.gov (United States)

    Cheng, Ting; Zhang, Guoqiang; Xia, Yonggao; Sun, Zaicheng; Yang, Zhaohui; Liu, Rui; Xiao, Ying; Wang, Xiaoyan; Wang, Meimei; Ban, Jianzhen; Yang, Liangtao; Ji, Qing; Qiu, Bao; Chen, Guoxin; Chen, Huifeng; Lin, Yichao; Pei, Xiaoying; Wu, Qiang; Meng, Jian-Qiang; Liu, Zhaoping; Chen, Liang; Xiao, Tonghu; Sun, Ling-Dong; Yan, Chun-Hua; Butt, Hans Jürgen; Cheng, Ya-Jun

    2016-05-01

    A new strategy to synthesize hierarchical, porous titania/carbon (TiO2/C) hybrid microspheres via solvothermal reaction in N,N'-dimethyl formamide (DMF) has been developed. In situ formed polystyrene (PS) colloids have been used as templating agent and carbon source, through which TiO2/PS microspheres with a diameter of ca. 1 μm are built by packed TiO2 nanoparticles of tens of nanometers. The TiO2/PS microspheres are converted to TiO2/C microspheres with different amounts of carbon under controlled calcination condition. The mechanism investigation unveils that the introduction of concentrated HCl creates surface tension between PS and DMF, leading to the formation of PS colloids in solution. The solvothermal treatment further promotes the formation of PS colloids and integration of the titania nanoparticles within the PS colloids. The morphology, crystallinity, nature and content of carbon, UV-Vis absorption, carbon doping, pore size distribution, pore volume, and BET surface area of the TiO2 microspheres with different amounts of carbon have been measured. The applications of the TiO2/C hybrid microspheres as photo catalyst for water splitting and lithium-ion battery anode have been demonstrated. Superior photo catalytic activity for hydrogen conversion under both full spectrum and visible light illumination compared to commercial P25 has been observed for the TiO2/C microspheres with 2 wt% of carbon. Besides, the TiO2/C microspheres with 8 wt% of carbon as lithium-ion battery anode showed a much higher capacity than the bare TiO2 microsphere anode. The origin for the enhanced performance as photo catalyst and lithium-ion battery anode is discussed.

  8. Porous SnIn4S8 microspheres in a new polymorph that promotes dyes degradation under visible light irradiation.

    Science.gov (United States)

    Yan, Tingjiang; Li, Liping; Li, Guangshe; Wang, Yunjian; Hu, Wanbiao; Guan, Xiangfeng

    2011-02-15

    Porous SnIn(4)S(8) microspheres were initially synthesized through a facile solvothermal approach and were investigated as visible-light driven photocatalysts for dyes degradation in polluted water. The photocatalysts were characterized by XRD, SEM, TEM, N(2) adsorption-desorption, and UV-vis diffuse reflectance techniques. Results demonstrated that the as-synthesized SnIn(4)S(8) was of a new tetragonal polymorph, showing a band-gap of 2.5 eV, a specific surface area of 197 m(2) g(-1), and an accessible porous structure as well. The photocatalytic activity of the porous SnIn(4)S(8) was evaluated by decomposition of several typical organic dyes including methyl orange, rhodamine B, and methylene blue in aqueous solution under visible light irradiation. It is demonstrated that porous SnIn(4)S(8) was highly photoactive and stable for dyes degradation, showing photocatalytic activity much higher than binary constituent sulfides like In(2)S(3), SnS(2), or even ternary chalcogenide ZnIn(2)S(4) photocatalyst. The excellent photocatalytic performance of porous SnIn(4)S(8) is the consequence of its high surface area, well-defined porous texture, and large amount of hydroxyl radicals.

  9. Facile synthesis and Li-ion storage properties of porous Mn-based oxides microspheres

    Science.gov (United States)

    Hou, Xiaojuan; Zhu, Jie; Shi, Shuzheng; He, Jian; Mu, Jiliang; Geng, Wenping; Chou, Xiujian; Xue, Chenyang

    2017-05-01

    Porous nanosheets assembled Mn-based oxides (Mn2O3, MnCo2O4 and CoMn2O4) microspheres of diameters about 3-6 μm and pore size distribution mainly around 10 nm have been synthesized by the same facile solvothermal route without any surfactant followed by a calcination process. In virtue of the porous nanosheets constructed microspheres, the Mn-based oxides microspheres Mn2O3 present specific capacities of 650 mAh/g after 100 charge and discharge cycles. Additionally among the three Mn-based oxides the representative specific capacities present an increasing trend as with the increasing percentage of Co element, the plateau of charge and discharge present a lower trend as with the increasing percentage of Mn element which is more suitable as anode materials in high output full batteries. Then the oxides with different components could be applied in different conditions such as the need for high specific capacity or high output lithium-ion batteries. Consequently the easy fabrication of microspheres and excellent electrochemical performances demonstrate Mn-based oxides' great potential in lithium-ion batteries.

  10. Porous LiFePO4/C microspheres as high-power cathode materials for lithium ion batteries.

    Science.gov (United States)

    Sun, Bing; Wang, Ying; Wang, Bei; Kim, Hyun-Soo; Kim, Woo-Seong; Wang, Guoxiu

    2013-05-01

    Porous LiFePO4/C microspheres were synthesized by a novel hydrothermal reaction combined with high-temperature calcinations. The morphology of the prepared material was investigated by field-emission scanning electron microscopy. Porous microspheres with diameters around 1-3 microm were obtained, which consisting of primary LiFePO4 nanoparticles. The electrochemical performances of the as-prepared LiFePO4 microspheres were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling. The carbon coated LiFePO4 microspheres showed lower polarization, higher rate capability, and better cycling stability than that of pristine LiFePO4 microspheres, indicating the potential application as the cathode material for high-power lithium ion batteries.

  11. Fabrication of a porous fiber cladding material using microsphere templating for improved response time with fiber optic sensor arrays.

    Science.gov (United States)

    Henning, Paul E; Rigo, M Veronica; Geissinger, Peter

    2012-01-01

    A highly porous optical-fiber cladding was developed for evanescent-wave fiber sensors, which contains sensor molecules, maintains guiding conditions in the optical fiber, and is suitable for sensing in aqueous environments. To make the cladding material (a poly(ethylene) glycol diacrylate (PEGDA) polymer) highly porous, a microsphere templating strategy was employed. The resulting pore network increases transport of the target analyte to the sensor molecules located in the cladding, which improves the sensor response time. This was demonstrated using fluorescein-based pH sensor molecules, which were covalently attached to the cladding material. Scanning electron microscopy was used to examine the structure of the templated polymer and the large network of interconnected pores. Fluorescence measurements showed a tenfold improvement in the response time for the templated polymer and a reliable pH response over a pH range of five to nine with an estimated accuracy of 0.08 pH units.

  12. SDS-assisted hydrothermal synthesis of porous CdIn2S4 microspheres

    Science.gov (United States)

    Bai, X. F.; Li, J. S.; Wu, W.

    2017-02-01

    The porous CdIn2S4 microspheres were synthesized via a sodium dodecyl sulfate (SDS)-assisted hydrothermal technology. The as-prepared CdIn2S4 products were characterized by X-ray diffraction, field emission scanning electron microscopy and UV-Vis diffusive reflectance spectroscopy. The results showed that hydrothermal time and the surfactant addition had great effect on the structure, morphology and optical property of CdIn2S4 products.

  13. Highly porous ZnS microspheres for superior photoactivity after Au and Pt deposition and thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Singla, Shilpa; Pal, Bonamali, E-mail: bpal@thapar.edu

    2013-11-15

    Graphical abstract: Highly porous ZnS microsphere of size 2–5 μm having large surface area ca. 173.14 m{sup 2} g{sup −1} exhibits superior photocatalytic activity for the oxidation of 4-nitrophenol under UV light irradiation. The rate of photooxidation has been significantly improved by Au and Pt deposition and after sintering, respectively, due to rapid electron acceptance by metal from photoexcited ZnS and growth of crystalline ZnS phase. - Highlights: • Photoactive ZnS microsphere of size 2–5 μm was prepared by hydrothermal route. • Highly porous cubic spherical ZnS crystals possess a large surface area, 173 m{sup 2} g{sup −1}. • 1 wt% Au and Pt photodeposition highly quenched the photoluminescence at 437 nm. • Sintering and metal loading notably improve the photooxidation rate of 4-nitrophenol. • Pt co-catalyst always exhibits superior photoactivity of ZnS microsphere than Au. - Abstract: This work highlights the enhanced photocatalytic activity of porous ZnS microspheres after Au and Pt deposition and heat treatment at 500 °C for 2 h. Microporous ZnS particles of size 2–5 μm with large surface area 173.14 m{sup 2} g{sup −1} and pore volume 0.0212 cm{sup 3} g{sup −1} were prepared by refluxing under an alkaline medium. Photoluminescence of ZnS at 437 nm attributed to sulfur or zinc vacancies were quenched to 30% and 49%, respectively, after 1 wt% Au and Pt loading. SEM images revealed that each ZnS microparticle consist of several smaller ZnS spheres of size 2.13 nm as calculated by Scherrer's equation. The rate of photooxidation of 4-nitrophenol (10 μM) under UV (125 W Hg arc–10.4 mW/cm{sup 2}) irradiation has been significantly improved by Au and Pt deposition followed by sintering due to better electron capturing capacity of deposited metals and growth of crystalline ZnS phase with less surface defects.

  14. Fast Preparation of Porous MnO/C Microspheres as Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Su, Jing; Liang, Hao; Gong, Xian-Nian; Lv, Xiao-Yan; Long, Yun-Fei; Wen, Yan-Xuan

    2017-01-01

    Porous MnO/C microspheres have been successfully fabricated by a fast co-precipitation method in a T-shaped microchannel reactor. The structures, compositions, and electrochemical performances of the obtained MnO/C microspheres are characterized by X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller analysis, charge-discharge testing, cyclic voltammograms, and electrochemical impedance spectra. Experimental results reveal that the as-prepared MnO/C, with a specific surface area of 96.66 m2·g−1 and average pore size of 24.37 nm, exhibits excellent electrochemical performance, with a discharge capacity of 655.4 mAh·g−1 after cycling 50 times at 1 C and capacities of 808.3, 743.7, 642.6, 450.1, and 803.1 mAh·g−1 at 0.2, 0.5, 1, 2, and 0.2 C, respectively. Moreover, the controlled method of using a microchannel reactor, which can produce larger specific surface area porous MnO/C with improved cycling performance by shortening lithium-ion diffusion distances, can be easily applied in real production on a large scale. PMID:28587120

  15. Effect of Synthesis Time on Morphology of Hollow Porous Silica Microspheres

    Directory of Open Access Journals (Sweden)

    Qian CHEN

    2012-03-01

    Full Text Available Hollow porous silica microspheres may be applicable as containers for the controlled release in drug delivery systems (DDS, foods, cosmetics, agrochemical, textile industry, and in other technological encapsulation use. In order to control the surface morphological properties of the silica microspheres, the effect of synthesis time on their formation was studied by a method of water-in-oil (W/O emulsion mediated sol-gel techniques. An aqueous phase of water, ammonium hydroxide and a surfactant Tween 20 was emulsified in an oil phase of 1-octanol with a stabilizer, hydroxypropyl cellulose (HPC, and a surfactant, sorbitan monooleate (Span 80 with low hydrophile-lipophile balance (HLB value. Tetraethyl orthosilicate (TEOS as a silica precursor was added to the emulsion. The resulting silica particles at different synthesis time 24, 48, and 72 hours were air-dried at room temperature and calcinated at 773 K for 3 hours. The morphology of the particles was characterized by scanning electron microscopy and the particle size distribution was measured by laser diffraction. The specific surface areas were studied by 1-point BET method, and pore sizes were measured by Image Tool Software. Both dense and porous silica microspheres were observed after all three syntheses. Hollow porous silica microspheres were formed at 24 and 48 hours synthesis time. Under base catalyzed sol-gel solution, the size of silica particles was in the range of 5.4 μm to 8.2 μm, and the particles had surface area of 111 m2/g – 380 m2/g. The longer synthesis time produced denser silica spheres with decreased pore sizes.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1344

  16. Effect of Synthesis Time on Morphology of Hollow Porous Silica Microspheres

    Directory of Open Access Journals (Sweden)

    Qian CHEN

    2012-03-01

    Full Text Available Hollow porous silica microspheres may be applicable as containers for the controlled release in drug delivery systems (DDS, foods, cosmetics, agrochemical, textile industry, and in other technological encapsulation use. In order to control the surface morphological properties of the silica microspheres, the effect of synthesis time on their formation was studied by a method of water-in-oil (W/O emulsion mediated sol-gel techniques. An aqueous phase of water, ammonium hydroxide and a surfactant Tween 20 was emulsified in an oil phase of 1-octanol with a stabilizer, hydroxypropyl cellulose (HPC, and a surfactant, sorbitan monooleate (Span 80 with low hydrophile-lipophile balance (HLB value. Tetraethyl orthosilicate (TEOS as a silica precursor was added to the emulsion. The resulting silica particles at different synthesis time 24, 48, and 72 hours were air-dried at room temperature and calcinated at 773 K for 3 hours. The morphology of the particles was characterized by scanning electron microscopy and the particle size distribution was measured by laser diffraction. The specific surface areas were studied by 1-point BET method, and pore sizes were measured by Image Tool Software. Both dense and porous silica microspheres were observed after all three syntheses. Hollow porous silica microspheres were formed at 24 and 48 hours synthesis time. Under base catalyzed sol-gel solution, the size of silica particles was in the range of 5.4 μm to 8.2 μm, and the particles had surface area of 111 m2/g – 380 m2/g. The longer synthesis time produced denser silica spheres with decreased pore sizes.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1344

  17. Synthesis of novel porous magnetic silica microspheres as adsorbents for isolation of genomic DNA.

    Science.gov (United States)

    Zhang, Zhichao; Zhang, Liming; Chen, Lei; Chen, Ligong; Wan, Qian-Hong

    2006-01-01

    An improved procedure is described for preparation of novel mesoporous microspheres consisting of magnetic nanoparticles homogeneously dispersed in a silica matrix. The method is based on a three-step process, involving (i) formation of hematite/silica composite microspheres by urea-formaldehyde polymerization, (ii) calcination of the composite particles to remove the organic constituents, and (iii) in situ transformation of the iron oxide in the composites by hydrogen reductive reaction. The as-synthesized magnetite/silica composite microspheres were nearly monodisperse, mesoporous, and magnetizable, with as typical values an average diameter of 3.5 microm, a surface area of 250 m(2)/g, a pore size of 6.03 nm, and a saturation magnetization of 9.82 emu/g. These magnetic particles were tested as adsorbents for isolation of genomic DNA from Saccharomyces cerevisiae cells and maize kernels. The results are quite encouraging as the magnetic particle based protocols lead to the extraction of genomic DNA with satisfactory integrity, yield, and purity. Being hydrophilic in nature, the porous magnetic silica microspheres are considered a good alternative to polystyrene-based magnetic particles for use in biomedical applications where nonspecific adsorption of biomolecules is to be minimized.

  18. Facile Synthesis of Porous Nickel/Carbon Composite Microspheres with Enhanced Electromagnetic Wave Absorption by Magnetic and Dielectric Losses.

    Science.gov (United States)

    Qiu, Song; Lyu, Hailong; Liu, Jiurong; Liu, Yuzhen; Wu, Nannan; Liu, Wei

    2016-08-10

    Porous nickel/carbon (Ni/C) composite microspheres with diameters of ca. 1.2-1.5 μm were fabricated by a solvothermal method combined with carbon reduction. The pore size of the synthesized Ni/C composite microspheres ranged from several nanometers to 50 nm. The porous Ni/C composite microspheres exhibited a saturation magnetization (MS) of 53.5 emu g(-1) and a coercivity (HC) of 51.4 Oe. When tested as an electromagnetic (EM) wave absorption material, the epoxy resin composites containing 60% and 75% porous Ni/C microspheres provided high-performance EM wave absorption at thicknesses of 3.0-11.0 and 1.6-7.0 mm in the corresponding frequency ranges of 2.0-12 and 2.0-18 GHz, respectively. The superior EM wave absorption performances of porous Ni/C composite microspheres were derived from the synergy effects generated by the magnetic loss of nickel, the dielectric loss of carbon, and the porous structure.

  19. Size-dependent filtration of nanoparticles on porous films composed by polystyrene microsphere monolayers and applications in site-selective deposition of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Weidong [Jilin University, State Key Laboratory of Supramolecular Structure and Materials (China); Zhou, Tieli [Changchun University, College of Food Engineering and Landscape Architecture (China); Sun, Chengbin; Tao, Yanchun; Lu, Fei; Wang, Xu; Zhao, Bing, E-mail: zhaob@mail.jlu.edu.cn [Jilin University, State Key Laboratory of Supramolecular Structure and Materials (China); Cui, Yinqiu, E-mail: cuiyq@jlu.edu.cn [Jilin University, School of Life Sciences (China)

    2015-10-15

    Composite films composed of polystyrene (PS) microsphere monolayers and gold (Au) and/or silver (Ag) nanoparticles (NPs) decorations were prepared by a novel size-dependent filtration effect on close-packed PS microsphere arrays. The uniform pores inlaid in the PS monolayer films acted as the transport tunnels for NPs. The steric restriction induced by the size of the pores was used as a main strategy to fabricate hybrid micro/nano films, which were composed of PS microspheres with inhomogeneous anisotropic decorations. The Au and Ag NPs were used as the building blocks to decorate the PS microspheres through a layer-by-layer self-assembly technique with the aid of polyelectrolyte coupling agents. Only the small particles which could pass through the micropores could reach to and deposit on the inner surfaces of the PS microsphere monolayer films. Large particles remained on the outside and could only deposit on the outer surfaces. Thus, the inhomogeneous anisotropic decoration was obtained. This study provides a novel strategy for fabricating anisotropic micro/nanostructures by the size-dependent filtration effect of NPs on porous films and has the potential in applications of anisotropic self-assembly, sensor, and surface modifications at nanoscale.

  20. Biotin- and glycoprotein-coated microspheres: potential surrogates for studying filtration of cryptosporidium parvum in porous media.

    Science.gov (United States)

    Pang, Liping; Nowostawska, Urszula; Weaver, Louise; Hoffman, Gabrielle; Karmacharya, Anjuman; Skinner, Alexandra; Karki, Naveena

    2012-11-06

    Cryptosporidium parvum is a waterborne pathogen, yet no suitable surrogate has been established for quantifying its filtration removal in porous media. Carboxyl polystyrene microspheres with size, density, and shape similar to C. parvum were coated with biotin (free and containing amine, NH(2)) and glycoprotein. These biomolecules have isoelectric points similar to C. parvum (pH ≈ 2), and glycoprotein is a major type of surface protein that oocysts possess. Zeta potential (ζ) and filtration removal of particles in sand of two different grain sizes were examined. Compared to unmodified microspheres, modified microspheres achieved a superior match to the oocysts in ζ, concentration, mass recovery, and collision coefficient. They showed the same log reduction in concentration as oocysts, whereas results from unmodified microspheres deviated by 1 order of magnitude. Of the three types of modified microspheres, glycoprotein-coated microspheres best resembled oocyst concentration, despite having ζ similar to NH(2)-biotin-coated microspheres, suggesting that surface protein also played an important role in particle attachment on solid surfaces. With further validation in environmental conditions, the surrogates developed here could be a cost-effective new tool for assessing oocyst filtration in porous media, for example, to evaluate the performance of sand filters in water and wastewater treatment, water recycling through riverbank filtration, and aquifer recharge.

  1. Synthesis of porous Fe3O4 hollow microspheres/graphene oxide composite for Cr(vi) removal.

    Science.gov (United States)

    Liu, Mancheng; Wen, Tao; Wu, Xilin; Chen, Changlun; Hu, Jun; Li, Jie; Wang, Xiangke

    2013-10-01

    A composite of porous Fe3O4 hollow microspheres/graphene oxide (Fe3O4/GO) has been fabricated through a facile self-assembly approach. Driven by the mutual electrostatic interactions, the amine-functionalized Fe3O4 microspheres prepared by a hydrothermal method and then modified by 3-aminopropyltrimethoxysilane were decorated with negatively-charged GO sheets. The Fe3O4 microspheres were hollow with porous surfaces and the surfaces were successfully modified with the amine, which was confirmed by Fourier transform infrared spectroscopy. The specific saturation magnetization of Fe3O4/GO was 37.8 emu g(-1). The sorption performance of Fe3O4/GO for Cr(vi) was evaluated. The maximum sorption capacity for Cr(vi) on Fe3O4/GO was 32.33 mg g(-1), which was much higher than that of Fe3O4 microspheres. The GO sheets could not only prevent agglomeration of the Fe3O4 microspheres and enable a good dispersion of these oxide microspheres, but also substantially enhance the specific surface area of the composite. The Fe3O4/GO composite may be a promising sorption material for the separation and preconcentration of heavy metal ions from aqueous solutions in environmental pollution cleanup.

  2. Polypropylene nonwoven surface modified through introducing porous microspheres: Preparation, characterization and adsorption

    Science.gov (United States)

    Du, Xiao; Wei, Junfu; Liu, Wei; Zhou, Xiangyu; Dai, Danyang

    2016-01-01

    A new porous fabric adsorbent (PM/PP nonwoven) was prepared by hydrogen bonding self-assembly method, in which poly(divinylbenzene-co-4-vinylpyridine) microspheres were introduced onto the surface of PP-g-AA (polypropylene grafted acrylic acid) nonwoven. The effects of the main conditions for self-assembly reaction such as mass ratio of microsphere to nonwoven, pH and the grafting degree of acrylic acid were studied. In addition, the adsorption mechanisms and interactions for three VOCs (styrene, cyclohexane, acetone) were systematically elucidated. The resulting 28.2% PM/PP nonwoven obtained a higher adsorption amount (52.8 mg/g) of styrene vapor, which was 88 times greater than that of original PP nonwoven. Meanwhile, the kinetic studies suggested that the Yoon and Nelson model is suitable to describe the adsorption mechanism of styrene over the modified nonwovens. Adsorption and pressure drop data showed that PM/PP nonwoven had good adsorption ability and air permeability due to its abundant functional groups and porous structures. Taken together, it is expected that PM/PP nonwoven would be a promising adsorbent for removal of VOCs from the gas streams.

  3. Polydopamine-Coated Porous Microspheres Conjugated with Immune Stimulators for Enhanced Cytokine Induction in Macrophages.

    Science.gov (United States)

    Jang, Hyo-Eun; Mok, Hyejung

    2016-11-01

    Polydopamine-coated porous microsphere (PPM) is investigated as a simple and versatile immobilization strategy for immune-stimulating biomolecules to enhance delivery efficiency and immune-stimulating effects such as cytokine induction in macrophages. The PPMs, with diameters of about 2 μm, exhibit simultaneous and efficient incorporation of biomolecules (nucleotides and proteins), which is comparable to that achieved using microspheres carrying biomolecules internally by virtue of their porous structure. Ovalbumin-conjugated PPMs are internalized into macrophages efficiently and selectively via the phagocytic pathway, without any noticeable toxicity. Internalized CpG oligodeoxynucleotide (ODN)-conjugated PPMs (PPM-CpG) greatly enhance the induction of selected cytokines (TNF-α and IL-6) in RAW 264.7 cells compared to that by the soluble CpG ODN and ionic complexes. Therefore, PPMs generated in this study may serve as effective carriers of immune-stimulating biomolecules such as diverse toll-like receptor agonists. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Hydrothermal synthesis of 3D hollow porous Fe3O4 microspheres towards catalytic removal of organic pollutants.

    Science.gov (United States)

    Wang, Xiansong; Huang, He; Li, Guoqing; Liu, Yi; Huang, Jiale; Yang, Da-Peng

    2014-01-01

    Three-dimensional hollow porous superparamagnetic Fe3O4 microspheres were synthesized via a facile hydrothermal process. A series of characterizations done with X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy indicated that the production of Fe3O4 microspheres possessed good monodispersity, uniform size distribution, hollow and porous structural characters, and strong superparamagnetic behavior. The obtained Fe3O4 microspheres have a diameter of ca. 300 nm, which is composed of many interconnected nanoparticles with a size of ca. 20 nm. The saturation magnetization is 80.6 emu·g(-1). The as-prepared products had promising applications as novel catalysts to remove organic pollutants (methylene blue) from wastewater in the presence of H2O2 and ultrasound irradiation.

  5. One-pot template-free synthesis of porous CdMoO4 microspheres and their enhanced photocatalytic activity

    Science.gov (United States)

    Madhusudan, Puttaswamy; Zhang, Jinfeng; Yu, Jiaguo; Cheng, Bei; Xu, Difa; Zhang, Jun

    2016-11-01

    The optical and catalytic performances of materials strongly depend on their size, morphology, dimensionality and structure. Herein, we demonstrate a facile one-pot template free synthesis of hierarchical CdMoO4 porous microspheres via a simple low temperature oil bath method. The photoactivity of the as-prepared samples was evaluated by photocatalytic decolorization of Methyl Orange (MO) and Methylene Blue (MB) mixed dye aqueous solutions at ambient temperature under full solar spectrum. The results indicated that the concentration of ammonium molybdate and reaction time greatly influence the diameter, average crystallite size, specific surface area, pore structure and photocatalytic activity of the prepared samples. Especially, under the suitable conditions the prepared hierarchical CdMoO porous microspheres exhibited enhanced photocatalytic activity and high stability. Furthermore, it is found that the photocatalytic activity and formation rate of hydroxyl radicals greatly depend on the particle sizes and morphology of as-prepared samples. This work not only demonstrates a simple way to fabricate the hierarchical CdMoO4 porous microspheres but also shows a possibility for utilization of CdMoO4 porous microspheres for the photocatalytic treatment of waste water pollutants.

  6. PREPARATION OF MONODISPERSE POLYSTYRENE MICROSPHERES BY SHELL POROUS GLASS-SUSPENSION POLYMERIZATION%用多孔玻璃膜管-悬浮聚合法制备单分散性聚苯乙烯微球

    Institute of Scientific and Technical Information of China (English)

    范星河; 谢晓峰

    2001-01-01

    Monodisperse polystyrene microspheres are prepared by shell porous glass(SPG)-suspension polymerization. The influences of SPG on size and size dispersity of the microspheres are investigated. The properties of the microspheres are studied by GPC, TEM and SEM. The results indicate that the polystyrene microspheres possess definite monodispersibity and their particle size is in the range of 5~12μm.

  7. Synthesis, characterization and enhanced gas sensing performance of porous ZnCo2O4 nano/microspheres.

    Science.gov (United States)

    Liu, Tie; Liu, Jingyuan; Liu, Qi; Song, Dalei; Zhang, Hongseng; Zhang, Hongquan; Wang, Jun

    2015-12-14

    In recent years, spinel-type compounds have attracted great interest because of their gem-like qualities. However, little is known of their gas sensing properties. We report, in this paper, on a self-assembly method to prepare porous ZnCo2O4 (ZCO) nano/microspheres by a facile one-step solvothermal process and subsequent annealing. Abundant techniques were used to characterize the morphology and structure of the as-obtained compounds. Our data indicate that the hierarchical nano/microspheres are constructed from numerous nanoparticles primarily, which have a higher specific surface area (ca. 77.3 m(2) g(-1)) and are of uniform diameter (ca. 1 μm). To demonstrate their potential application, gas sensors based on the as-synthesized ZCO nano/microspheres were fabricated to test their sensing performance, whose sensing behaviours correspond to p-type semiconductors. The test results also indicate that porous spinel-type compounds have an excellent kinetic response to ethanol at an operating temperature of 175 °C and a superior selectivity. As such, hierarchical porous ZnCo2O4 nano/microspheres will hold promising potential in the gas sensor field.

  8. Validation of large-scale, monochromatic UV disinfection systems for drinking water using dyed microspheres.

    Science.gov (United States)

    Blatchley, E R; Shen, C; Scheible, O K; Robinson, J P; Ragheb, K; Bergstrom, D E; Rokjer, D

    2008-02-01

    Dyed microspheres have been developed as a new method for validation of ultraviolet (UV) reactor systems. When properly applied, dyed microspheres allow measurement of the UV dose distribution delivered by a photochemical reactor for a given operating condition. Prior to this research, dyed microspheres had only been applied to a bench-scale UV reactor. The goal of this research was to extend the application of dyed microspheres to large-scale reactors. Dyed microsphere tests were conducted on two prototype large-scale UV reactors at the UV Validation and Research Center of New York (UV Center) in Johnstown, NY. All microsphere tests were conducted under conditions that had been used previously in biodosimetry experiments involving two challenge bacteriophage: MS2 and Qbeta. Numerical simulations based on computational fluid dynamics and irradiance field modeling were also performed for the same set of operating conditions used in the microspheres assays. Microsphere tests on the first reactor illustrated difficulties in sample collection and discrimination of microspheres against ambient particles. Changes in sample collection and work-up were implemented in tests conducted on the second reactor that allowed for improvements in microsphere capture and discrimination against the background. Under these conditions, estimates of the UV dose distribution from the microspheres assay were consistent with numerical simulations and the results of biodosimetry, using both challenge organisms. The combined application of dyed microspheres, biodosimetry, and numerical simulation offers the potential to provide a more in-depth description of reactor performance than any of these methods individually, or in combination. This approach also has the potential to substantially reduce uncertainties in reactor validation, thereby leading to better understanding of reactor performance, improvements in reactor design, and decreases in reactor capital and operating costs.

  9. Porous wall hollow glass microsphere as an optical microresonator for chemical vapor detection

    Science.gov (United States)

    Wang, Hanzheng; Yuan, Lei; Kim, Cheol-Woon; Pienkowski, Edward; Xiao, Hai

    2012-02-01

    Optical microresonators have been proven effective for developing sensitive chemical and biological sensors by monitoring the changes in refractive index or mass near the resonator surface. The rotationally symmetric structures support high quality (Q) whispering gallery modes (WGMs) that interact with the local environment through the evanescent field. The long photon lifetime of the high-Q resonator (thus the long light-material interaction path) is the key reason that a microresonator can achieve very high sensitivity in detection. In this paper, we present our recent research on using porous wall hollow glass microsphere (PW-HGM) as an optical microresonator for chemical vapor detection. The diameter of the PW-HGM ranges from 10μm to 100μm. The wall thickness is about 2μm and the pore size is about 20nm. The Q-factors and free spectrum ranges (FSR) of PW-HGMs were measured by coupling light into the PW-HGM using a single mode fiber taper. Various types of chemical vapors were used to characterize the PW-HGM resonator. The resonant wavelength shift was measured as a function of vapor concentration. Comparisons between a PW-HGM and a solid glass microsphere indicated that a PW-HGM can effectively adsorb vapor molecules into its nanosized pores, providing a direct and long light-material interaction path for significant sensitivity enhancement for chemical vapor detection.

  10. Microfluidic Fabrication of Porous Polymer Microspheres: Dual Reactions in Single Droplets

    KAUST Repository

    Gong, Xiuqing

    2009-06-16

    We report the microfluidic fabrication of macroporous polymer microspheres via the simultaneous reactions within single droplets, induced by LTV irradiation. The aqueous phase of the reaction is the decomposition of H 2O2 to yield oxygen, whereas the organic phase is the polymerization of NO A 61, ethylene glycol dimethacrylate (EGDMA), and tri (propylene glycol) diacrylate (TPGDA) precursors. We first used a liquid polymer precursor to encapsulate a multiple number of magnetic Fe3O 4 colloidal suspension (MCS) droplets in a core-shell structure, for the purpose of studying the number of such encapsulated droplets that can be reliably controlled through the variation of flow rates. It was found that the formation of one shell with one, two, three, or more encapsulated droplets is possible. Subsequently, the H2O2 solution was encapsulated in the same way, after which we investigated its decomposition under UV irradiation, which simultaneously induces the polymerization of the encapsulating shell. Because the H2O2 decomposition leads to the release of oxygen, porous microspheres were obtained from a combined H2O2 decomposition/polymer precursor polymerization reaction. The multiplicity of the initially encapsulated H2O 2 droplets ensures the homogeneous distribution of the pores. The pores inside the micrometer-sized spheres range from several micrometers to tens of micrometers, and the maximum internal void volume fraction can attain 70%, similar to that of high polymerized high internal phase emulsion (polyHIPE). © 2009 American Chemical Society.

  11. Preparation and characterization of magnetic porous carbon microspheres for removal of methylene blue by a heterogeneous Fenton reaction.

    Science.gov (United States)

    Zhou, Lincheng; Shao, Yanming; Liu, Junrui; Ye, Zhengfang; Zhang, He; Ma, Junjun; Jia, Yan; Gao, Weijie; Li, Yanfeng

    2014-05-28

    High-specific-surface-area magnetic porous carbon microspheres (MPCMSs) were fabricated by annealing Fe(2+)-treated porous polystyrene (PS) microspheres, which were prepared using a two-step seed emulsion polymerization process. The resulting porous microspheres were then sulfonated, and Fe(2+) was loaded by ion exchange, followed by annealing at 250 °C for 1 h under an ambient atmosphere to obtain the PS-250 composite. The MPCMS-500 and MPCMS-800 composites were obtained by annealing PS-250 at 500 and 800 °C for 1 h, respectively. The iron oxide in MPCMS-500 mainly existed in the form of Fe3O4, which was concluded by characterization. The MPCMS-500 carbon microspheres were used as catalysts in heterogeneous Fenton reactions to remove methylene blue (MB) from wastewater with the help of H2O2 and NH2OH. The results indicated that this catalytic system has a good performance in terms of removal of MB; it could remove 40 mg L(-1) of MB within 40 min. After the reaction, the catalyst was conveniently separated from the media within several seconds using an external magnetic field, and the catalytic activity was still viable even after 10 removal cycles. The good catalytic performance of the composites could be attributed to synergy between the functions of the porous carbon support and the Fe3O4 nanoparticles embedded in the carrier. This work indicates that porous carbon spheres provide good support for the development of a highly efficient heterogeneous Fenton catalyst useful for environmental pollution cleanup.

  12. Large deformations of a soft porous material

    CERN Document Server

    MacMinn, Christopher W; Wettlaufer, John S

    2015-01-01

    Compressing a porous material will decrease the volume of pore space, driving fluid out. Similarly, injecting fluid into a porous material can drive mechanical deformation, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with linear elasticity and then further linearizing in the strain. This is a good model for very small deformations, but it becomes increasingly inappropriate as deformations grow larger, and moderate to large deformations are common in the context of phenomena such as swelling or damage, or for materials that are extremely soft. Here, we first review a rigorous Eulerian framework for large-deformation poromechanics. We then compare the predictions of linear poroelasticity with those of fully nonlinear poromechanics in the context of two uniaxial model problems: Fluid outflow driven by an applied mec...

  13. Immobilization of salvianolic acid B-loaded chitosan microspheres distributed three-dimensionally and homogeneously on the porous surface of hydroxyapatite scaffolds.

    Science.gov (United States)

    Li, Jinyu; Wang, Qin; Zhi, Wei; Wang, Jianxin; Feng, Bo; Qu, Shuxin; Mu, Yandong; Weng, Jie

    2016-10-07

    Porous hydroxyapatite (HA) scaffolds combined with a drug delivery system have attracted much attention for bone tissue engineering. In this study, an easy and highly efficient method was developed to immobilize salvianolic acid B (Sal B)-loaded chitosan (CS) microspheres three dimensionally and homogeneously on the surface of HA scaffolds pre-coated with alginate. Porous HA scaffolds were prepared via a template-leaching process and CS microspheres (used as drug carriers) were fabricated by an emulsion method. To improve adhesion between the microspheres and HA scaffolds, alginate was used to pre-coat the porous surface of the HA scaffolds. Various concentrations of alginate were used to optimize the adhesion of Sal B-loaded CS microspheres to the scaffold surface. During the adherence process, coated HA scaffolds were immersed in an aqueous solution containing Sal B-loaded CS microspheres, followed by standing or shaking at 37 °C for a certain time. The results showed that the microspheres were solidly and homogeneously distributed on the porous surface of the alginate pre-coated HA scaffolds via electrostatic interactions. Few microspheres detached from the porous surface, even after the HA scaffolds with microspheres were treated by shaking in distilled water for as long as 7 d. Compared with the static condition, the distribution of Sal B-loaded CS microspheres on the porous surface of pre-coated HA scaffolds in the shaken condition was more homogeneous and almost unaggregated. Additionally, the compressive strength of the scaffolds coated with alginate was obviously improved. The optimal alginate coating concentration was 1% (i.e. the microstructure of the porous surfaces of the HA scaffolds was almost unchanged). The release profile of Sal B over a 30 d immersion found an initial burst release followed by a sustained release. The result of cell culture in vitro was that 1% alginate-coated scaffolds with Sal B-loaded CS microspheres obviously promoted cell

  14. Thermo-stabilized, porous polyimide microspheres prepared from nanosized SiO2 templating via in situ polymerization

    Directory of Open Access Journals (Sweden)

    M. Q. Liu

    2015-01-01

    Full Text Available In this article, we addressed a feasible and versatile method of the fabrication of porous polyimide microspheres presenting excellent heat resistance. The preparation process consisted of two steps. Firstly, a novel polyimide/nano-silica composite microsphere was prepared via the self-assembly structures of poly(amic acid (PAA, precursor of PI/nanosized SiO2 blends after in situ polymerization, following the two-steps imidization. Subsequently, the encapsulated nanoparticles were etched away by hydrofluoric acid treatment, giving rise to the pores. It is found the composite structure of PI/SiO2 is a precondition of the formation of nanoporous structures, furthermore, the morphology of the resultant pore could be relatively tuned by changing the content and initial morphology of silica nano-particles trapped into PI matrix. The thermal properties of the synthesized PI porous spheres were studied, indicating that the introduction of nanopores could not effectively influence the thermal stabilities of PI microspheres. Moreover, the fabrication technique described here may be extended to other porous polymer systems.

  15. Large Deformations of a Soft Porous Material

    Science.gov (United States)

    MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.

    2016-04-01

    Compressing a porous material will decrease the volume of the pore space, driving fluid out. Similarly, injecting fluid into a porous material can expand the pore space, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with Terzaghi's effective stress and linear elasticity in a linearized kinematic framework. Linear poroelasticity is a good model for very small deformations, but it becomes increasingly inappropriate for moderate to large deformations, which are common in the context of phenomena such as swelling and damage, and for soft materials such as gels and tissues. The well-known theory of large-deformation poroelasticity combines Darcy's law with Terzaghi's effective stress and nonlinear elasticity in a rigorous kinematic framework. This theory has been used extensively in biomechanics to model large elastic deformations in soft tissues and in geomechanics to model large elastoplastic deformations in soils. Here, we first provide an overview and discussion of this theory with an emphasis on the physics of poromechanical coupling. We present the large-deformation theory in an Eulerian framework to minimize the mathematical complexity, and we show how this nonlinear theory simplifies to linear poroelasticity under the assumption of small strain. We then compare the predictions of linear poroelasticity with those of large-deformation poroelasticity in the context of two uniaxial model problems: fluid outflow driven by an applied mechanical load (the consolidation problem) and compression driven by a steady fluid throughflow. We explore the steady and dynamical errors associated with the linear model in both situations, as well as the impact of introducing a deformation-dependent permeability. We show that the error in linear poroelasticity is due primarily to kinematic

  16. Biogenic synthesis and catalysis of porous CeO2 hollow microspheres

    Institute of Scientific and Technical Information of China (English)

    CHEN Feng; WANG Wei; CHEN Zhigang; WANG Taibin

    2012-01-01

    Porous CeO2 hollow microspheres were successfully prepared through a facile process by using the rape pollen as the biotemplate.Scanning electron microscopy (SEM),transmission electron microscopy (TEM),the N2 adsorption and desorption,X-ray diffraction (XRD),UV-vis diffuse reflectance spectra,and hydrogen temperature-programmed reduction (H2-TPR) were used for their characterization.The results showed that the obtained materials exhibited the same morphology as that of the pollen template,with a diameter of ca.10 μm,and the surface was evenly covered with a special network-like structure with mesh size of about 0.3 μm,and the Brunauer-Emmett-Teller (BET) surface area was measured to be 156 m2/g.The detailed property investigation inferred that the product exhibited better photocatalytic activity in acid fuchsine decolorization under daylight because of higher surface area,smaller crystallite size and higher oxygen capacity.

  17. Hydrophilic porous magnetic poly(GMA-MBAA-NVP) composite microspheres containing oxirane groups: An efficient carrier for immobilizing penicillin G acylase

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Ping; Su, Weiguang, E-mail: weiguangsu@nxu.edu.cn; Gu, Yaohua; Liu, Haifeng; Wang, Julan

    2015-03-15

    Magnetic hydrophilic polymeric microspheres containing oxirane groups were prepared by inverse suspension polymerization of glycidyl methacrylate (GMA), N, N′-methylene bisacrylamide (MBAA) and N-vinyl pyrrolidone (NVP) in the existence of formamide, which were denoted as magnetic poly(GMA-MBAA-NVP) microspheres. The magnetic poly(GMA-MBAA-NVP) microspheres were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy, X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and so on. The results showed that poly(GMA-MBAA-NVP) microspheres possessed well spherical shape, narrow size distribution, abundant porous structure, reactive oxirane groups and superparamagnetic properties. Formamide used in the present work served as a modifier, a dispersant and a porogen to form final porous polymer microspheres. The penicillin G acylase (PGA) was covalently immobilized onto the magnetic microspheres through the reaction between the amino groups of enzyme and the oxirane groups on the microspheres for producing 6-aminopenicillanic acid (6-APA). The effects of GMA/NVP ratio and crosslink density on the activity of immobilized PGA were investigated. The highest apparent activity, enzyme loading and coupling yield of immobilized PGA were 821 IU/g, 65.3 mg/g and 42.3% respectively when the mass ratio of GMA/NVP was 1:1 and crosslink density was 60%. Compared with the free PGA, immobilized PGA showed a wider range of pH value and reaction temperature. The relative activity and reaction rate of immobilized PGA remained almost constant after 20 recycles. The magnetic poly(GMA-MBAA-NVP) microspheres would be very promising carriers for immobilizing enzymes in industrial application. - Highlights: • The magnetic poly(GMA-MBAA-NVP) microspheres were successfully synthesized. • Formamide served as a modifier, a dispersant and a porogen to form microspheres. • The magnetic microspheres were highly efficient carriers for immobilizing PGA. • Immobilized PGA

  18. Production of Hollow Bacterial Cellulose Microspheres Using Microfluidics to Form an Injectable Porous Scaffold for Wound Healing.

    Science.gov (United States)

    Yu, Jiaqing; Huang, Tzu-Rung; Lim, Zhen Han; Luo, Rongcong; Pasula, Rupali Reddy; Liao, Lun-De; Lim, Sierin; Chen, Chia-Hung

    2016-12-01

    Bacterial cellulose (BC) is a biocompatible material with high purity and robust mechanical strength used to fabricate desirable scaffolds for 3D cell culture and wound healing. However, the chemical resistance of BC and its insolubility in the majority of solutions make it difficult to manipulate using standard chemical methods. In this study, a microfluidic process is developed to produce hollow BC microspheres with desirable internal structures and morphology. Microfluidics is used to generate a core-shell structured microparticle with an alginate core and agarose shell as a template to encapsulate Gluconacetobacter xylinus for long-term static culture. G. xylinus then secretes BC, which becomes entangled within the shell of the structured hydrogel microparticles and forms BC microspheres. The removal of the hydrogel template via thermal-chemical treatments yields robust BC microspheres exhibiting a hollow morphology. These hollow microspheres spontaneously assemble as functional units to form a novel injectable scaffold. In vitro, a highly porous scaffold is created to enable effective 3D cell culture with a high cell proliferation rate and better depth distribution. In vivo, this injectable scaffold facilitates tissue regeneration, resulting in rapid wound-healing in a Sprague Dawley rat skin model. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Biochemistry-directed hollow porous microspheres: bottom-up self-assembled polyanion-based cathodes for sodium ion batteries.

    Science.gov (United States)

    Lin, Bo; Li, Qiufeng; Liu, Baodong; Zhang, Sen; Deng, Chao

    2016-04-21

    Biochemistry-directed synthesis of functional nanomaterials has attracted great interest in energy storage, catalysis and other applications. The unique ability of biological systems to guide molecule self-assembling facilitates the construction of distinctive architectures with desirable physicochemical characteristics. Herein, we report a biochemistry-directed "bottom-up" approach to construct hollow porous microspheres of polyanion materials for sodium ion batteries. Two kinds of polyanions, i.e. Na3V2(PO4)3 and Na3.12Fe2.44(P2O7)2, are employed as cases in this study. The microalgae cell realizes the formation of a spherical "bottom" bio-precursor. Its tiny core is subjected to destruction and its tough shell tends to carbonize upon calcination, resulting in the hollow porous microspheres for the "top" product. The nanoscale crystals of the polyanion materials are tightly enwrapped by the highly-conductive framework in the hollow microsphere, resulting in the hierarchical nano-microstructure. The whole formation process is disclosed as a "bottom-up" mechanism. Moreover, the biochemistry-directed self-assembly process is confirmed to play a crucial role in the construction of the final architecture. Taking advantage of the well-defined hollow-microsphere architecture, the abundant interior voids and the highly-conductive framework, polyanion materials show favourable sodium-intercalation kinetics. Both materials are capable of high-rate long-term cycling. After five hundred cycles at 20 C and 10 C, Na3V2(PO4)3 and Na(3.12)Fe2.44(P2O7)2 retain 96.2% and 93.1% of the initial capacity, respectively. Therefore, the biochemistry-directed technique provides a low-cost, highly-efficient and widely applicable strategy to produce high-performance polyanion-based cathodes for sodium ion batteries.

  20. Porous microspheres as promising vehicles for the topical delivery of poorly soluble asiaticoside accelerate wound healing and inhibit scar formation in vitro &in vivo.

    Science.gov (United States)

    Zhang, Chen-Zhen; Niu, Jie; Chong, Yee-Song; Huang, Yan-Fen; Chu, Yang; Xie, Sheng-Yang; Jiang, Zhi-Hong; Peng, Li-Hua

    2016-12-01

    Asiaticoside is a natural compound possessing diverse pharmacological effects with great potential for clinical use. However, the low solubility and oil-water partition coefficient of asiaticoside lead to reduced effect and limited application. This study aims to construct a porous microsphere for the sustained release of asiaticoside to improve its absorption and enhance the therapeutic effects. Parameters of the formulations, including the drug to polymer ratio, solvent amounts of the inner and external phases, the stirring speed for preparation, and the drug entrapment efficiency were investigated and optimized. Particle size, morphology, pores structure, and Fourier transform infrared spectrum of the microsphere were characterized. The release kinetics and cellular uptake profiles of the asiaticoside-microspheres were examined. The therapeutic effects of asiaticoside-microspheres on wound healing and skin appendages regeneration were investigated in vitro & in vivo. Results showed that the optimized asiaticoside-microspheres possess spherical spongy structure with cylindrical holes. Asiaticoside can be loaded in the microsphere with high efficiency and released with sustained manner. The cellular uptake of asiaticoside from the microspheres was increased with 9.1 folds higher than that of free solution. Asiaticoside-microspheres expressed the strong promotion in the proliferation, migration of keratinocytes and wound scratching healing in vitro. More importantly, they significantly accelerated the re-epithelization, collagen synthesis and pro-angiogenesis in the rat full-skin wound healing. Porous microsphere was shown a novel carrier for the sustained delivery of poorly soluble asiaticoside, with absorption and therapeutic effects improved. Asiaticoside-microsphere is a promising topical preparation with excellent regenerative effects for the wound therapy.

  1. Three-dimensional study of poly(lactic co-glycolic acid) micro-porous microspheres using hard X-ray nano-tomography.

    Science.gov (United States)

    Wang, Dajiang; Li, Na; Wang, Zhili; Gao, Kun; Zhang, Yongming; Luo, Yuyan; Wang, Shengxiang; Bao, Yuan; Shao, Qigang; Wu, Ziyu

    2014-09-01

    Poly(lactic co-glycolic acid) (PLGA) is widely used in diverse fields, especially in delivering biologically active proteins and drugs. For these applications, the knowledge of morphology and microstructure of PLGA micro-porous microspheres is of great importance since they strongly influence the drug delivering efficiency. In this study, micro-porous PLGA microspheres loaded by bovine serum albumin are investigated by using a full-field Zernike phase contrast transmission hard X-ray microscope. From three-dimensional reconstructions and segmentations, fundamental microstructural parameters such as size, shape, distribution and volume ratio among pores and proteins inside PLGA microspheres were obtained. These parameters are useful to understand the relationship between the internal microstructure and drug encapsulation, as well as the drug release efficiency of PLGA microspheres. The presented results demonstrate the capability of hard X-ray nano-tomography to characterize porous microspheres loaded with proteins and drugs, and also open a way to analyse, optimize and design new PLGA microspheres for specific applications.

  2. Fabrication of porous ethyl cellulose microspheres based on the acetone-glycerin-water ternary system: Controlling porosity via the solvent-removal mode.

    Science.gov (United States)

    Murakami, Masahiro; Matsumoto, Akihiro; Watanabe, Chie; Kurumado, Yu; Takama, Masashi

    2015-08-01

    Porous ethyl cellulose (EC) microspheres were prepared from the acetone-glycerin-water ternary system using an oil/water (O/W)-type emulsion solvent extraction method. The O/ W type emulsion was prepared using acetone dissolved ethyl cellulose as an oil phase and aqueous glycerin as a water phase. The effects of the different solvent extraction modes on the porosity of the microspheres were investigated. The specific surface area of the porous EC microspheres was estimated by the gas adsorption method. When the solvent was extracted rapidly by mixing the emulsion with water instantaneously, porous EC microspheres with a maximum specific surface area of 40.7±2.1 m2/g were obtained. On the other hand, when water was added gradually to the emulsion, the specific surface area of the fabricated microspheres decreased rapidly with an increase in the infusion period, with the area being 25-45% of the maximum value. The results of an analysis of the ternary phase diagram of the system suggested that the penetration of water and glycerin from the continuous phase to the dispersed phase before solidification affected the porosity of the fabricated EC microspheres.

  3. Controllable promotion of chondrocyte adhesion and growth on PVA hydrogels by controlled release of TGF-β1 from porous PLGA microspheres.

    Science.gov (United States)

    Nie, Lei; Zhang, Guohua; Hou, Ruixia; Xu, Haiping; Li, Yaping; Fu, Jun

    2015-01-01

    Poly(vinyl alcohol) (PVA) hydrogels have been candidate materials for cartilage tissue engineering. However, the cell non-adhesive nature of PVA hydrogels has been a limit. In this paper, the cell adhesion and growth on PVA hydrogels were promoted by compositing with transform growth factor-β1 (TGF-β1) loaded porous poly(D,L-lactide-co-glycolide) (PLGA) microspheres. The porous microspheres were fabricated by a modified double emulsion method with bovine serum albumin (BSA) as porogen. The average pore size of microspheres was manipulated by changing the BSA/PLGA ratio. Such controllable porous structures effectively influenced the encapsulation efficiency (Eencaps) and release profile of TGF-β1. By compositing PVA hydrogels with such TGF-β1-loaded PLGA microspheres, chondrocyte adhesion and proliferation were significantly promoted in a controllable manner, as confirmed by fluorescent imaging and quantitative CCK-8 assay. That is, the chondrocyte proliferation was favored by using PLGA microspheres with high Eencaps of TGF-β1 or by increasing the PLGA microsphere content in the hydrogels. These results demonstrated a facile method to improve the cell adhesion and growth on the intrinsically cell non-adhesive PVA hydrogels, which may find applications in cartilage substitution.

  4. Core-shell microspheres with porous nanostructured shells for liquid chromatography.

    Science.gov (United States)

    Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

    2017-10-10

    The development of new stationary phase has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules, and metabolites. In this review, we firstly introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles, and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects.

    Science.gov (United States)

    Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

    2015-01-01

    The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m(2)/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration.

  6. Nano-particle assembled porous core–shell ZnMn2O4 microspheres with superb performance for lithium batteries

    Science.gov (United States)

    Zhang, Tong; Yue, Huijuan; Qiu, Hailong; Wei, Yingjin; Wang, Chunzhong; Chen, Gang; Zhang, Dong

    2017-03-01

    Porous ZnMn2O4 microspheres were prepared via a facile co-precipitation method followed by calcination at various temperatures and evaluated as anode materials for lithium ion batteries. The sample prepared at 600 °C outperformed the other samples in terms of electrochemical performance with high reversible capacity, high-rate capability, and excellent cycling performance. The capacity of the sample remained as high as 999 mAh g‑1 at a current rate of 100 mA g‑1 after 50 cycles—one of the best ever reported for ZnMn2O4-based materials. A high reversible capacity of 400 mAh g‑1 was retainable at a current density of 2000 mA g‑1 after 2500 cycles. A novel electrochemical reaction mechanism of ZnMn2O4 anodes was established and investigated at length. The Mn3O4 observed during the charge process was largely responsible for the enhanced performance, as confirmed by x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The relatively large surface area, abundant porosity, large ion exchange space, and strong mechanical stability of the porous connected 3D framework were responsible for the unique oxidation/reduction Mn2+ ↔ Mn3+ process we observed.

  7. Facile fabrication of poly(L-lactic acid) microsphere-incorporated calcium alginate/hydroxyapatite porous scaffolds based on Pickering emulsion templates.

    Science.gov (United States)

    Hu, Yang; Ma, Shanshan; Yang, Zhuohong; Zhou, Wuyi; Du, Zhengshan; Huang, Jian; Yi, Huan; Wang, Chaoyang

    2016-04-01

    In this study, we develop a facile one-pot approach to the fabrication of poly(L-lactic acid) (PLLA) microsphere-incorporated calcium alginate (ALG-Ca)/hydroxyapatite (HAp) porous scaffolds based on HAp nanoparticle-stabilized oil-in-water Pickering emulsion templates, which contain alginate in the aqueous phase and PLLA in the oil phase. The emulsion aqueous phase is solidified by in situ gelation of alginate with Ca(2+) released from HAp by decreasing pH with slow hydrolysis of D-gluconic acid δ-lactone (GDL) to produce emulsion droplet-incorporated gels, followed by freeze-drying to form porous scaffolds containing microspheres. The pore structure of porous scaffolds can be adjusted by varying the HAp or GDL concentration. The compressive tests show that the increase of HAp or GDL concentration is beneficial to improve the compressive property of porous scaffolds, while the excessive HAp can lead to the decrease in compressive property. Moreover, the swelling behavior studies display that the swelling ratios of porous scaffolds reduce with increasing HAp or GDL concentration. Furthermore, hydrophobic drug ibuprofen (IBU) and hydrophilic drug bovine serum albumin (BSA) are loaded into the microspheres and scaffold matrix, respectively. In vitro drug release results indicate that BSA has a rapid release while IBU has a sustained release in the dual drug-loaded scaffolds. In vitro cell culture experiments verify that mouse bone mesenchymal stem cells can proliferate on the porous scaffolds well, indicating the good biocompatibility of porous scaffolds. All these results demonstrate that the PLLA microsphere-incorporated ALG-Ca/HAp porous scaffolds have a promising potential for tissue engineering and drug delivery applications.

  8. Biochemistry-directed hollow porous microspheres: bottom-up self-assembled polyanion-based cathodes for sodium ion batteries

    Science.gov (United States)

    Lin, Bo; Li, Qiufeng; Liu, Baodong; Zhang, Sen; Deng, Chao

    2016-04-01

    Biochemistry-directed synthesis of functional nanomaterials has attracted great interest in energy storage, catalysis and other applications. The unique ability of biological systems to guide molecule self-assembling facilitates the construction of distinctive architectures with desirable physicochemical characteristics. Herein, we report a biochemistry-directed ``bottom-up'' approach to construct hollow porous microspheres of polyanion materials for sodium ion batteries. Two kinds of polyanions, i.e. Na3V2(PO4)3 and Na3.12Fe2.44(P2O7)2, are employed as cases in this study. The microalgae cell realizes the formation of a spherical ``bottom'' bio-precursor. Its tiny core is subjected to destruction and its tough shell tends to carbonize upon calcination, resulting in the hollow porous microspheres for the ``top'' product. The nanoscale crystals of the polyanion materials are tightly enwrapped by the highly-conductive framework in the hollow microsphere, resulting in the hierarchical nano-microstructure. The whole formation process is disclosed as a ``bottom-up'' mechanism. Moreover, the biochemistry-directed self-assembly process is confirmed to play a crucial role in the construction of the final architecture. Taking advantage of the well-defined hollow-microsphere architecture, the abundant interior voids and the highly-conductive framework, polyanion materials show favourable sodium-intercalation kinetics. Both materials are capable of high-rate long-term cycling. After five hundred cycles at 20 C and 10 C, Na3V2(PO4)3 and Na3.12Fe2.44(P2O7)2 retain 96.2% and 93.1% of the initial capacity, respectively. Therefore, the biochemistry-directed technique provides a low-cost, highly-efficient and widely applicable strategy to produce high-performance polyanion-based cathodes for sodium ion batteries.Biochemistry-directed synthesis of functional nanomaterials has attracted great interest in energy storage, catalysis and other applications. The unique ability of

  9. Lifting a large object from an anisotropic porous bed

    Science.gov (United States)

    Karmakar, Timir; Raja Sekhar, G. P.

    2016-09-01

    An analytical study of two dimensional problem of lifting an object from the top of a fully saturated rigid porous bed is discussed. It is assumed that the porous bed is anisotropic in nature. The flow within the gap region between the object and the porous bed is assumed to be governed by Stokes equation while the flow within the porous bed is governed by Brinkman equation. The breakout phenomenon for different kinds of soil is reported. The effect of mechanical properties like anisotropic permeability, grain diameter size, and porosity on streamlines, velocity, and force is analyzed. Relevant comparison with C. C. Mei, R. W. Yeung, and K. F. Liu ["Lifting a large object from a porous bed," J. Fluid. Mech. 152, 203-215 (1985)] and Y. Chang, L. H. Huang and F. P. Y. Yang ["Two-dimensional lift-up problem for a rigid porous bed," Phys. Fluids, 27, 053101 (2015)] is done.

  10. Effect of large pore size of multifunctional mesoporous microsphere on removal of heavy metal ions.

    Science.gov (United States)

    Yuan, Qing; Li, Nan; Chi, Yue; Geng, Wangchang; Yan, Wenfu; Zhao, Ying; Li, Xiaotian; Dong, Bin

    2013-06-15

    Pore size of mesoporous materials is crucial for their surface grafting. This article develops a novel multifunctional microsphere with a large pore size mesoporous silica shell (ca. 10.3 nm) and a magnetic core (Fe₃O₄), which is fabricated using cetyltrimethylammonium bromide (CTAB) as pore-forming agents, tetraethyl orthosilicate (TEOS) as silicon source through a sol-gel process. Compared with small pore size mesoporous silica magnetic microspheres (ca. 2-4 nm), the large pore size one can graft 447 mg/g amino groups in order to adsorb more heavy metal ions (Pb(2+): 880.6 mg/g, Cu(2+): 628.3mg/g, Cd(2+): 492.4 mg/g). The metal-loaded multifunctional microspheres could be easily removed from aqueous solution by magnetic separation and regenerated easily by acid treatment. The results suggest that the large pore size multifunctional microspheres are potentially useful materials for high effectively adsorbing and removing different heavy metal ions in aqueous solution. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Photocatalytic hydrogen generation over porous ZnIn{sub 2}S{sub 4} microspheres synthesized via a CPBr-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xuefeng, E-mail: bxuefeng@163.net [Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040 (China); School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China); Li, Jinshu [School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China)

    2011-07-15

    Graphical abstract: ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. It could be seen from the SEM image that the flowerlike microspheres were composed of numerous nanosheets. Many slit-like pores were formed among the curved nanosheets. The porous structure benefited the adsorption of reactants, the diffuseness of products, the charge separation on surface, the transfer of the interfacial charge carriers and the charge carrier trapping. And porous ZnIn{sub 2}S{sub 4} photocatalyst exhibited higher photocatalytic activity than nonporous ZnIn{sub 2}S{sub 4} material. Highlights: {yields} A series of unique flower-like porous ZnIn{sub 2}S{sub 4} microspheres of hexagonal crystal phase as efficient visible-light photocatalysts have been synthesized through CPBr-assisted hydrothermal method. {yields} The CPBr addition would visibly influence the self-assemble growing and the crystal structure including the position and intensity of some peaks. {yields} We also found that the pH value plays a crucial role in the formation of ZnIn{sub 2}S{sub 4} porous microspheres and the influence of the pH on the structure of product has been first reported in our paper. {yields} The results showed that our as-synthesized porous ZnIn{sub 2}S{sub 4} microspheres possessed a specific surface area of 165.4 m{sup 2} g{sup -1} and performed higher visible-light photocatalytic activity than bulk ZnIn{sub 2}S{sub 4} for hydrogen evolution. The maximum H{sub 2} evolution rate of ZnIn{sub 2}S{sub 4} reaches 1544.8 {mu}mol/(h g). -- Abstract: Hexagonal ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. The structure, morphology and optical property of these prepared products were characterized by wide angle X-ray diffraction (WAXRD), small angle X-ray diffraction (SAXRD), UV-Vis diffusive reflectance spectroscopy (DRS), field emission scanning

  12. Pore-Scale Investigation of Micron-Size Polyacrylamide Elastic Microspheres (MPEMs) Transport and Retention in Saturated Porous Media

    KAUST Repository

    Yao, Chuanjin

    2014-05-06

    Knowledge of micrometer-size polyacrylamide elastic microsphere (MPEM) transport and retention mechanisms in porous media is essential for the application of MPEMs as a smart sweep improvement and profile modification agent in improving oil recovery. A transparent micromodel packed with translucent quartz sand was constructed and used to investigate the pore-scale transport, surface deposition-release, and plugging deposition-remigration mechanisms of MPEMs in porous media. The results indicate that the combination of colloidal and hydrodynamic forces controls the deposition and release of MPEMs on pore-surfaces; the reduction of fluid salinity and the increase of Darcy velocity are beneficial to the MPEM release from pore-surfaces; the hydrodynamic forces also influence the remigration of MPEMs in pore-throats. MPEMs can plug pore-throats through the mechanisms of capture-plugging, superposition-plugging, and bridge-plugging, which produces resistance to water flow; the interception with MPEM particulate filters occurring in the interior of porous media can enhance the plugging effect of MPEMs; while the interception with MPEM particulate filters occurring at the surface of low-permeability layer can prevent the low-permeability layer from being damaged by MPEMs. MPEMs can remigrate in pore-throats depending on their elasticity through four steps of capture-plugging, elastic deformation, steady migration, and deformation recovery. © 2014 American Chemical Society.

  13. Large area laser surface micro/nanopatterning by contact microsphere lens arrays

    Science.gov (United States)

    Sedao, X.; Derrien, T. J.-Y.; Romer, G. R. B. E.; Pathiraj, B.; Huis in `t Veld, A. J.

    2013-06-01

    Laser surface micro/nanopatterning by particle lens arrays is a well-known technique. Enhanced optical fields can be achieved on a substrate when a laser beam passes through a self-assembled monolayer of silica microspheres placed on the substrate. This enhanced optical field is responsible for ablative material removal from the substrate resulting in a patterned surface. Because of the laser ablation, the microspheres are often ejected from the substrate during laser irradiation. This is a major issue impeding this technique to be used for large area texturing. We explored the possibility to retain the spheres on the substrate surface during laser irradiation. A picosecond laser system (wavelength of 515 nm, pulse duration 6.7 ps, repetition rate 400 kHz) was employed to write patterns through the lens array on a silicon substrate. In this experimental study, the pulse energy was found to be a key factor to realize surface patterning and retain the spheres during the process. When the laser pulse energy is set within the process window, the microspheres stay on the substrate during and after laser irradiation. Periodic patterns of nanoholes can be textured on the substrate surface. The spacing between the nanoholes is determined by the diameter of the microspheres. The depth of the nanoholes varies, depending on the number of laser pulses applied and pulse energy. Large area texturing can be made using overlapping pulses obtained through laser beam scanning.

  14. Facile synthesis of α-Fe{sub 2}O{sub 3}@ porous hollow yeast-based carbonaceous microspheres for fluorescent whitening agent-VBL wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Pei; Tong, Zhiqing [College of Environmental Science and Engineering, Chang' an University, Xi' an 710054 (China); Bai, Bo, E-mail: baibochina@163.com [Key Laboratory of Tibetan Medicine Research, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001 (China)

    2016-03-15

    Porous hollow carbonaceous microspheres (PHCMs) fabricated from yeast cells by hydrothermal treatment have stimulated interest because of their outstanding chemical and physical properties. Herein, the functionalizations of PHCMs by further coating of α-Fe{sub 2}O{sub 3} nanoparticles onto the surface were carried out. The structure of resulted α-Fe{sub 2}O{sub 3}@PHCMs products were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and BET specific surface area measurements (BET), respectively. Its promising application was evaluated by the Fenton-like degradation of fluorescent whitening agent-VBL from aqueous solutions. - Graphical abstract: In this work, novel α-Fe{sub 2}O{sub 3}@porous hollow carbonaceous microspheres (α-Fe{sub 2}O{sub 3}@PHCMs) were synthesized through a combination of hydrothermal method and calcinations route and achieved excellent removal efficiency for fluorescent whitening Agent-VBL. - Highlights: • The hybrid α-Fe{sub 2}O{sub 3}@ porous hollow microspheres (PHCMs) were firstly fabricated. • The formation mechanism of α-Fe{sub 2}O{sub 3}@PHCMs microspheres was proposed and verified. • Dithizone played a key role in the synthesis of α-Fe{sub 2}O{sub 3}@PHCMs composites. • A favorable removal for the fluorescent whitening agent-VBL were achieved.

  15. Ibuprofen-loaded porous microspheres suppressed the progression of monosodium iodoacetate-induced osteoarthritis in a rat model.

    Science.gov (United States)

    Park, Jang Won; Yun, Young-Pil; Park, Kyeongsoon; Lee, Jae Yong; Kim, Hak-Jun; Kim, Sung Eun; Song, Hae-Ryong

    2016-11-01

    The objectives of this study were (1) to fabricate ibuprofen-loaded porous microspheres (IBU/PMSs), (2) to evaluate the in vitro anti-inflammatory effects of the microspheres using LPS-induced inflammation in cultured synoviocytes, and (3) to evaluate the in vivo effect of the IBU/PMSs on the progression of monosodium iodoacetate (MIA)-induced osteoarthritis (OA) in a rat model. A dose-dependent in vitro anti-inflammatory effect on pro-inflammatory cytokine markers (matrix metallopeptidase-3 (MMP-3), matrix metallopeptidase-13 (MMP-13), cyclooxygenase-2 (COX-2), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5)), interleukin-6 (IL-6), and tumor necrosis factor (TNF-α) was observed by confirming with real-time PCR analyses. In vivo, treatment with IBU/PMSs reduced MIA-stimulated mRNA expression of MMP-3, MMP-13, COX-2, ADAMTS-5, IL-6, and TNF-α in rat synoviocytes. In addition, we demonstrated that intra-articular IBU/PMSs suppressed the progression of MIA-induced OA in the rat model via anti-inflammatory mechanisms. In conclusion, IBU/PMSs are a promising therapeutic material to control the pain and progression of OA.

  16. BACTERIOPHAGE AND MICROSPHERE TRANSPORT IN SATURATED POROUS MEDIA: FORCED-GRADIENT EXPERIMENT AT BORDEN, ONTARIO

    Science.gov (United States)

    A two-well forced-gradient experiment involving virus and microsphere transport was carried out in a sandy aquifer in Borden, Ontario, Canada. Virus traveled at least a few meters in the experiment, but virus concentrations at observation points 1 and 2.54 m away from the injecti...

  17. Highly efficient and porous TiO2-coated Ag@Fe3O4@C-Au microspheres for degradation of organic pollutants

    Science.gov (United States)

    Shen, Mao; Chen, Suqing; Jia, Wenping; Fan, Guodong; Jin, Yanxian; Liang, Huading

    2016-12-01

    In this paper, we reported a novel hierarchical porous Ag@Fe3O4@C-Au@TiO2 core@shell microspheres with a highly photocatalytic activity and magnetically separable properties. The synthesis method is included of a Fe3O4 magnetic embedded Ag core (Ag@Fe3O4), an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe3O4@C-PEI), the grafting of Au nanoparticles on the surface of Ag@Fe3O4@C-PEI (Ag@Fe3O4@C-Au), and an ordered porous TiO2 structured shell. As an example of the applications, the photocatalytic activities of the samples were investigated by the reduction of Rhodamine B (RhB) under visible-light irradiation. The results show that the porous Ag@Fe3O4@C-Au@TiO2 core@shell microspheres display higher adsorption and photocatalytic activities compared to the pure porous TiO2 and Ag@Fe3O4@C@TiO2 microspheres, which are attributed to the local surface plasmon resonance (LSPR) by the Ag and Au nanoparticles and the high specific surface area.

  18. A biodegradable polymeric system for peptide–protein delivery assembled with porous microspheres and nanoparticles, using an adsorption/infiltration process

    Directory of Open Access Journals (Sweden)

    Alcalá-Alcalá S

    2013-06-01

    Full Text Available Sergio Alcalá-Alcalá, Zaida Urbán-Morlán, Irene Aguilar-Rosas, David Quintanar-Guerrero Laboratorio de Investigación y Posgrado en Tecnología Farmacéutica, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Cuautitlán Izcalli, Estado de México, México Abstract: A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(D,L-lactide-co-glycolide (PLGA was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres. Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95% and a slower release rate were seen (~20% of released leuprolide in 12 hours when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles. Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours

  19. Porous Hydroxyapatite Scaffold with Three-Dimensional Localized Drug Delivery System Using Biodegradable Microspheres

    Science.gov (United States)

    2011-03-21

    might be efficiently incorporated with calcium phosphate-based bioceramics using biodegradable polymeric microspheres. Published by Elsevier B.V. 1...induce stem cell differentiation would enhance the flexibility of integration into the surrounding tissue. Since calcium phosphate-based bioceramics ...kinetics and can affect the functionality of the HAp surface. If controlled release from HAp bioceramics is to be achieved, it will require the

  20. Porous yolk-shell microspheres as N-doped carbon matrix for motivating the oxygen reduction activity of oxygen evolution oriented materials

    Science.gov (United States)

    Zhou, Jinqiu; Wang, Mengfan; Qian, Tao; Liu, Sisi; Cao, Xuecheng; Yang, Tingzhou; Yang, Ruizhi; Yan, Chenglin

    2017-09-01

    It is highly challenging to explore high-performance bi-functional oxygen electrode catalysts for their practical application in next-generation energy storage and conversion devices. In this work, we synthesize hierarchical N-doped carbon microspheres with porous yolk-shell structure (NCYS) as a metal-free electrocatalyst toward efficient oxygen reduction through a template-free route. The enhanced oxygen reduction performances in both alkaline and acid media profit well from the porous yolk-shell structure as well as abundant nitrogen functional groups. Furthermore, such yolk-shell microspheres can be used as precursor materials to motivate the oxygen reduction activity of oxygen evolution oriented materials to obtain a desirable bi-functional electrocatalyst. To verify its practical utility, Zn-air battery tests are conducted and exhibit satisfactory performance, indicating that this constructed concept for preparation of bi-functional catalyst will afford a promising strategy for exploring novel metal-air battery electrocatalysts.

  1. Porous TiNb24O62 microspheres as high-performance anode materials for lithium-ion batteries of electric vehicles.

    Science.gov (United States)

    Yang, Chao; Deng, Shengjue; Lin, Chunfu; Lin, Shiwei; Chen, Yongjun; Li, Jianbao; Wu, Hui

    2016-11-10

    TiNb24O62 is explored as a new anode material for lithium-ion batteries. Microsized TiNb24O62 particles (M-TiNb24O62) are fabricated through a simple solid-state reaction method and porous TiNb24O62 microspheres (P-TiNb24O62) are synthesized through a facile solvothermal method for the first time. TiNb24O62 exhibits a Wadsley-Roth shear structure with a structural unit composed of a 3 × 4 octahedron-block and a 0.5 tetrahedron at the block-corner. P-TiNb24O62 with an average sphere size of ∼2 μm is constructed by nanoparticles with an average size of ∼100 nm, forming inter-particle pores with a size of ∼8 nm and inter-sphere pores with a size of ∼55 nm. Such desirable porous microspheres are an ideal architecture for enhancing the electrochemical performances by shortening the transport distance of electrons/Li(+)-ions and increasing the reaction area. Consequently, P-TiNb24O62 presents outstanding electrochemical performances in terms of specific capacity, rate capability and cyclic stability. The reversible capacities of P-TiNb24O62 are, respectively, as large as 296, 277, 261, 245, 222, 202 and 181 mA h g(-1) at 0.1, 0.5, 1, 2, 5, 10 and 20 C, which are obviously larger than those of M-TiNb24O62 (258, 226, 210, 191, 166, 147 and 121 mA h g(-1)). At 10 C, the capacity of P-TiNb24O62 still remains at 183 mA h g(-1) over 500 cycles with a decay of only 0.02% per cycle, whereas the corresponding values of M-TiNb24O62 are 119 mA h g(-1) and 0.04%. These impressive results indicate that P-TiNb24O62 can be a promising anode material for lithium-ion batteries of electric vehicles.

  2. In vitro bioactivity of bioresorbable porous polymeric scaffolds incorporating hydroxyapatite microspheres.

    Science.gov (United States)

    Li, L H; Kommareddy, K P; Pilz, C; Zhou, C R; Fratzl, P; Manjubala, I

    2010-07-01

    Biomimetic composites consisting of polymer and mineral components, resembling bone in structure and composition, were produced using a rapid prototyping technique for bone tissue engineering applications. Solid freeform fabrication, known as rapid prototyping (RP) technology, allows scaffolds to be designed with pre-defined and controlled external and internal architecture. Using the indirect RP technique, a three-component scaffold with a woodpile structure, consisting of poly-L-lactic acid (PLLA), chitosan and hydroxyapatite (HA) microspheres, was produced that had a macroporosity of more than 50% together with micropores induced by lyophilization. X-ray diffraction analysis indicated that the preparation and construction of the composite scaffold did not affect the phase composition of the HA. The compressive strength and elastic modulus (E) for the PLLA composites are 0.42 and 1.46 MPa, respectively, which are much higher than those of chitosan/HA composites and resemble the properties of cellular structure. These scaffolds showed excellent biocompatibility and ability for three-dimensional tissue growth of MC3T3-E1 pre-osteoblastic cells. The pre-osteoblastic cells cultured on these scaffolds formed a network on the HA microspheres and proliferated not only in the macropore channels but also in the micropores, as seen from the histological analysis and electron microscopy. The proliferating cells formed an extracellular matrix network and also differentiated into mature osteoblasts, as indicated by alkaline phosphatase enzyme activity. The properties of these scaffolds indicate that they can be used for non-load-bearing applications.

  3. Sulfur-infiltrated porous carbon microspheres with controllable multi-modal pore size distribution for high energy lithium-sulfur batteries.

    Science.gov (United States)

    Zhao, Cunyu; Liu, Lianjun; Zhao, Huilei; Krall, Andy; Wen, Zhenhai; Chen, Junhong; Hurley, Patrick; Jiang, Junwei; Li, Ying

    2014-01-21

    Sulfur has received increasing attention as a cathode material for lithium-sulfur (Li-S) batteries due to its high theoretical specific capacity. However, the commercialization of Li-S batteries is limited by the challenges of poor electrical conductivity of sulfur, dissolution of the polysulfide intermediates into the electrolyte, and volume expansion of sulfur during cycling. Herein, we report the fabrication of novel-structured porous carbon microspheres with a controllable multi-modal pore size distribution, i.e., a combination of interconnected micropores, mesopores and macropores. Cathodes made of sulfur infiltrated in such a hierarchical carbon framework provide several advantages: (1) a continuous and high surface area carbon network for enhanced electrical conductivity and high sulfur loading; (2) macropores and large mesopores bridged by small mesopores to provide good electrolyte accessibility and fast Li ion transport and to accommodate volume expansion of sulfur; and (3) small mesopores and micropores to improve carbon/sulfur interaction and to help trap polysulfides. An initial discharge capacity at 1278 mA h g(-1) and capacity retention at 70.7% (904 mA h g(-1)) after 100 cycles at a high rate (1 C) were achieved. The material fabrication process is relatively simple and easily scalable.

  4. Insightful understanding of the role of clay topology on the stability of biomimetic hybrid chitosan-clay thin films and CO2-dried porous aerogel microspheres.

    Science.gov (United States)

    Frindy, Sana; Primo, Ana; Qaiss, Abou El Kacem; Bouhfid, Rachid; Lahcini, Mohamed; Garcia, Hermenegildo; Bousmina, Mosto; El Kadib, Abdelkrim

    2016-08-01

    Three natural clay-based microstructures, namely layered montmorillonite (MMT), nanotubular halloysite (HNT) and micro-fibrillar sepiolite (SP) were used for the synthesis of hybrid chitosan-clay thin films and porous aerogel microspheres. At a first glance, a decrease in the viscosity of the three gel-forming solutions was noticed as a result of breaking the mutual polymeric chains interaction by the clay microstructure. Upon casting, chitosan-clay films displayed enhanced hydrophilicity in the order CSmicrospheres face the highest shrinkage, resulting in a lowest specific surface area compared to CS-HNT and CS-MMT. Chitosan-clay exhibits enhanced thermal properties with the degradation delayed in the order CSmicrospheres, which is attributed again to their increased hydrophilicity compared to the native polymeric microspheres. In this framework, a peculiar behavior was observed for CS-MMT, with the microspheres standing both against contraction during CO2 gel drying and under hydrothermal conditions. The knowledge gained from this rational design will constitute a guideline toward the preparation of ultra-stable, practically-optimized food-packaging films and commercially scalable porous bio-based adsorbents.

  5. Facile synthesis of hierarchical CoMn2O4 microspheres with porous and micro-/nanostructural morphology as anode electrodes for lithium-ion batteries

    Science.gov (United States)

    Li, Yana; Hou, Xianhua; Li, Yajie; Ru, Qiang; Wang, Shaofeng; Hu, Shejun; Lam, Kwok-ho

    2017-09-01

    Hierarchical CoMn2O4 microspheres assembled by nanoparticles have been successfully synthesized by a facile hydrothermal method and a subsequent annealing treatment. XRD detection indicate the crystal structure. SEM and TEM results reveal the 3-dimensional porous and micro-/nanostructural microsphere assembled by nanoparticles with a size of 20-100 nm. The CoMn2O4 electrode show initial specific discharge capacity of approximately 1546 mAh/g at the current rates 100 mA/g with a coulombic efficiency of 66.7% and remarkable specific capacities (1029-485 mAh/g) at various current rates (100-2800 mA/g). [Figure not available: see fulltext.

  6. Ti(IV) carrying polydopamine-coated, monodisperse-porous SiO2 microspheres with stable magnetic properties for highly selective enrichment of phosphopeptides.

    Science.gov (United States)

    Salimi, Kouroush; Usta, Duygu Deniz; Çelikbıçak, Ömür; Pinar, Asli; Salih, Bekir; Tuncel, Ali

    2017-05-01

    A marked decrease in the saturation magnetization by the formation of functional shells around the magnetic core is an important disadvantage of magnetic core-shell nanoparticles. Another drawback of Ti(IV)-functionalized immobilized metal affinity chromatography (IMAC) sorbents is the acidic character of the binding medium used for Ti(4+) attachment onto composite magnetic nanoparticles, which causes an additional decrease in the saturation magnetization owing to the chemical interaction between the acidic moiety and the magnetic core. An IMAC sorbent in the form of magnetic microspheres with superior and stable magnetic properties with respect to magnetic core-shell nanoparticles was designed for phosphopeptide enrichment. Magnetic, monodisperse-porous silica microspheres (MagSiO2) 6μm in size were synthesized by a new staged-shape template hydrolysis-condensation protocol. A porous-silica shell layer was generated around the microspheres to protect the magnetic core from the acidic medium during Ti(4+) attachment (MagSiO2@SiO2). The MagSiO2@SiO2 microspheres were coated with a polydopamine shell (MagSiO2@SiO2@PDA) and Ti(4+) was attached onto the composite microspheres (MagSiO2@SiO2@PDA@Ti(IV)). Formation of the PDA layer and Ti(4+) attachment did not cause any significant decrease in the saturation magnetization. The platform exhibited excellent performance for phosphopeptide enrichment from the digests of phosphorylated proteins. Selectivity was investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The detection limit for phosphopeptide enrichment by the MagSiO2@SiO2@PDA@Ti(IV) microspheres from the tryptic digests of β-casein was 50 fmol/mL. Usability of the proposed magnetic sorbent with complex biological samples was demonstrated by successful enrichment of four phosphopeptides from human serum. The proposed sorbent showed stable performance over five repeated uses. Copyright © 2017 Elsevier B.V. All rights

  7. In-situ anion exchange fabrication of porous ZnO/ZnSe heterostructural microspheres with enhanced visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hairui, E-mail: liuhairui1@126.com [College of Physics & Electrics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Hu, Yanchun [College of Physics & Electrics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); He, Xia [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); Jia, Husheng, E-mail: jia_husheng@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Liu, Xuguang; Xu, Bingshe [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China)

    2015-11-25

    Porous ZnO microspheres were fabricated by an ultrasonic irradiation technique. Subsequently, through a facile in-situ anion exchange reaction between the ZnO microsphere and sodium selenite, spherical ZnO/ZnSe heterostructures with different ratios of the two components were fabricated. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV–vis spectrometry. The results reveal that the secondary ZnSe nanoparticles are grown on the surface of pre-grown ZnO microspheres. Compared with pure ZnO microspheres, the ZnO/ZnSe hetero-microspheres show enhance visible-light photocatalytic activity for degradation of methylene blue (MB) and 4-nitrophenol (4-NP). The enhanced photocatalytic performance is attributed to fast separation and transport of photogenerated electrons and holes derived from the coupling effect of ZnSe and ZnO heterostructure. Photoluminescent spectra further indicate that the ZnO/ZnSe heterostructures greatly suppress the charge recombination of photogenerated electron–hole pairs, which would be beneficial to improve their photocatalytic activity. Finally, the photocatalytic mechanism of the ZnO/ZnSe heterostructures is proposed. - Graphical abstract: Porous ZnO/ZnSe heterostructures with different ratios of the two components were fabricated and present enhance visible-light photocatalytic activity for degradation of methylene blue (MB) and 4-nitrophenol (4-NP). The enhanced photocatalytic performance is attributed to fast separation and transport of photogenerated electrons and holes derived from the coupling effect of ZnSe and ZnO heterostructure. - Highlights: • Spherical ZnO/ZnSe porous composites were fabricated by in-situ anion exchange. • ZnO/ZnSe composites exhibited enhanced visible-light photocatalytic activity. • The matching band gap improves the separation of

  8. Synthesis, characterization and photocatalytic activity of porous WO{sub 3}/TiO{sub 2} hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liuyang [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Si, Zhichun, E-mail: emsztsinghua@126.com [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Weng, Duan [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); State Key Laboratory of New Ceramics and Fine Process, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yao, Youwei [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2014-09-15

    Porous WO{sub 3}/TiO{sub 2} hollow microspheres were prepared by a spray drying method for photodegradation of methylene blue and phenol. The catalysts were characterized by X-ray diffraction, Field Emission Scanning Electron Microscope, High Resolution Transmission Electron Microscope, N{sub 2} adsorption–desorption measurements, Raman spectrometer, UV–Vis Diffuse Reflectance Spectroscopy and Zeta-Meter measurements. The results showed that the tungsten oxides mainly existed in highly dispersed amorphous form on anatase when the loading amount of tungsten oxide was below 3 mol%. The improved photocatalytic activity under UV light irradiation of the WO{sub 3}/TiO{sub 2} catalyst mainly arises from the enhanced charge separation efficiency rather than the improved light absorbance by highly dispersed amorphous tungsten oxides. Highly dispersed amorphous WO{sub x} can form a shallowly trapped site due to its similar band structure with TiO{sub 2}. The strongly electron-withdrawing of tungsten oxide in highly dispersed state facilitates the electron transition between titanium and WO{sub x}, and consequently improves the charge separation. The enhanced acidity of catalyst by WO{sub x} in reactant environment also improved the charge separation efficiency due to the timely transition of holes and electrons accumulated on TiO{sub 2} and WO{sub x}, respectively. However, the improved photocatalytic activity under visible light irradiation of the WO{sub 3}/TiO{sub 2} catalyst mainly arises from light harvest. TiO{sub 2} containing 3 mol% WO{sub 3} displayed the highest photocatalytic activity under UV light irradiation while that containing 4 mol% WO{sub 3} present highest activity under visible light irradiation.

  9. Porous microspheres of manganese-cerium mixed oxides by a polyvinylpyrrolidone assisted solvothermal method

    Science.gov (United States)

    Schmit, F.; Bois, L.; Chiriac, R.; Toche, F.; Chassagneux, F.; Descorme, C.; Besson, M.; Khrouz, L.

    2017-04-01

    Mixed cerium manganese oxides were synthesized using a polyvinylpyrrolidone (PVP) assisted solvothermal method. Materials obtained after calcination at 400 °C were characterized by X-ray diffraction, scanning and transmission electron microscopies, electron paramagnetic resonance (EPR), Raman spectroscopy, thermal analysis and nitrogen adsorption/desorption isotherms. The influence of the synthesis parameters on the oxide structure, such as the Mn:Ce ratio or the amount of PVP, was discussed. Micrometric spheres of mixed Mn-Ce oxides, resulting from the aggregation of 100 nm porous snowflakes, were successfully synthesized. These snowflakes were formed from the aggregation of smaller oriented crystallites (size 4 nm). The hydrothermal stability of these materials was also investigated.

  10. Application of Porous Microspheres in the Field of Medicine and Pharmacy%多孔微球在医药领域的应用

    Institute of Scientific and Technical Information of China (English)

    杨晓霞; 栾玉霞; 蔡晓青; 庞建梅; 姜悦

    2011-01-01

    As a new drug dosage form, porous microsphere has been widely used in the development of new formulations and the transformation of new dosage form of porous microsphers have rich resources,such as natural polymer materials,inorganic materials, polymer molecules etc. As a new carrier for drug controlled/sustained release,microspheres have numerous advantages as follows: protecting the drug from degradation, having special affinity to some cells or tissues, controling the release rate and prolonging the function time of the drug,reducing the drug toxicity and decreasing the drug amount. It also can be used for drug's target in some specific organs and tissues. What is more,porous microspheres have a rather big surface area and pore volume,which makes them easy for drug adsorbed on the surface or trapped in the pore. Thus drugs can be made into immediate-release or sustained-release formulations according to body needs. The review deals with the current development of several typical porous microspheres and their applications in biomedical field.%多孔微球作为一种药物新剂型,在药物新制剂的研发以及新剂型的改造方面应用广泛.多孔微球材料来源丰富,如天然高分子材料,无机材料,合成大分子聚合物等.作为一种新型缓/控释给药载体,微球具有保护药物免遭破坏、与某些细胞组织有特殊的亲和性、控制药物释放速度、延长药物作用时间、减少药物不良反应及降低用药量等优点,还可用于特定组织和器官的药物靶向释放等.由于多孔微球具有巨大的比表面积和孔体积,药物可吸附在多孔微球的表面或进入孔道内部,根据机体需要被做成速释或缓释制剂而发挥药效.该文综述了几种典型的多孔微球材料研究概况及其在生物医药领域中的应用,并对其发展前景进行展望.

  11. Transarterial embolisation of a large focal nodular hyperplasia, using microspheres, in a paediatric patient.

    Science.gov (United States)

    Oliveira, Catarina; Gil-Agostinho, Alfredo; Gonçalves, Isabel; Noruegas, Maria José

    2015-07-10

    Benign liver tumours are uncommon in children, haemangiomas being the most frequent. Focal nodular hyperplasia (FNH) represents about 2% of paediatric liver tumours. In children, as in adults, a conservative approach is generally recommended. However, large lesions (greater than 5 cm) are more frequent in the paediatric age group, and in these cases, as well as in growing lesions, surgical removal may be advised. Transarterial embolisation (TAE) has been a successful alternative option described in older patients, especially in cases where surgical removal is not possible. This minimally invasive procedure may also become an option in the paediatric group. The authors report the case of a boy with a large FNH treated with TAE using microspheres. 2015 BMJ Publishing Group Ltd.

  12. The preparation of composite microsphere with hollow core/porous shell structure by self-assembling of latex particles at emulsion droplet interface.

    Science.gov (United States)

    He, Xiao Dong; Ge, Xue Wu; Wang, Mo Zhen; Zhang, Zhi Cheng

    2006-07-15

    A submicrometer-scaled polystyrene/melamine-formaldehyde hollow microsphere composite was prepared by self-assembling of sulfonated polystyrene (SPS) latex particles at the interface of emulsion droplets and then being fixed in place using a hard melamine-formaldehyde (MF) composite layer. For control-released purposes, the influential factors that control the size and uniformity of the packed-droplets and the permeability of the composite shell, including the initial particle location, the hydrophilicity and the size of colloidal templates, the oil phase solvent and reserving time of emulsions after the addition of MF prepolymer, were further studied. Relatively uniform sized particle packed-droplets with an average diameter of 10 microm were obtained. The assembled SPS particles kept ordering and minimal conglutination after the preparation of composite microspheres, which allows of controlling the permeability from the interstices between the particles. Porous-mesh-structured MF composite layer was formed to further control the permeability. The morphology of emulsions and composite microspheres were characterized by optical microscopy, scanning and transmission electron microscopy.

  13. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  14. Reduction of ethylenediaminetetraacetic acid iron(III) by Klebsiella sp. FD-3 immobilized on iron(II, III) oxide poly (styrene-glycidyl methacrylate) magnetic porous microspheres: effects of inorganic compounds and kinetic study of effective diffusion in porous media.

    Science.gov (United States)

    Zhou, Zuo-Ming; Wang, Xiao-Yan; Lin, Tian-Ming; Jing, Guo-Hua

    2014-11-01

    Fe3O4 poly (styrene-glycidyl methacrylate) magnetic porous microspheres (MPPMs) were introduced to immobilize Klebsiella sp. FD-3, an iron-reducing bacterium applied to reduce Fe(III)EDTA. The effects of potential inhibitors (S(2-), SO3(2-), NO3(-), NO2(-) and Fe(II)EDTA-NO) on Fe(III)EDTA reduction were investigated. S(2-) reacted with Fe(III)EDTA as an electron-shuttling compound and enhanced the reduction. But Fe(III)EDTA reduction was inhibited by SO3(2-) and Fe(II)EDTA-NO due to their toxic to microorganisms. Low concentrations of NO3(-) and NO2(-) accelerated Fe(III)EDTA reduction, but high concentrations inhibited the reduction, whether by free or immobilized FD-3. The immobilized FD-3 performed better than freely-suspended style. The substrate mass transfer and diffusion kinetics in the porous microspheres were calculated. The value of Thiele modulus and effectiveness factors showed that the intraparticle diffusion was fairly small and neglected in this carrier. Fe(III)EDTA reduction fitted first-order model at low Fe(III)EDTA concentration, and changed to zero-order model at high concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Polymeric Microspheres for Medical Applications

    Directory of Open Access Journals (Sweden)

    Ketie Saralidze

    2010-06-01

    Full Text Available Synthetic polymeric microspheres find application in a wide range of medical applications. Among other applications, microspheres are being used as bulking agents, embolic- or drug-delivery particles. The exact composition of the spheres varies with the application and therefore a large array of materials has been used to produce microspheres. In this review, the relation between microsphere synthesis and application is discussed for a number of microspheres that are used for different treatment strategies.

  16. The preparation of porous superfine calcium carbonate microspheres%多孔超细碳酸钙微球的制备

    Institute of Scientific and Technical Information of China (English)

    杨辉; 李欢

    2013-01-01

    采用乳状液膜与共沉淀结合法制备多孔超细碳酸钙微球,考察了不同反应条件对碳酸钙微球形貌的影响.通过X射线衍射、扫描电子显微镜及激光粒度仪对所得的碳酸钙微球的晶体组成、形貌以及粒度进行了表征.结果表明,超细碳酸钙微球生成的最佳工艺条件为:CaCl2溶液浓度0.1 mol/L、吐温-80加量4 mL、超声乳化5 min、搅拌反应3 h ,此工艺条件下获得多孔碳酸钙微球粒径在2~10μm ,球形圆整,且组成为球霰石与方解石的共混体.%The porous superfine calcium carbonate microspheres was prepared by using a e-mulsion liquid membrane method combining with a precipitation method in this paper . Effects of different reaction conditions on the calcium carbonate microspheres morphology were investigated ,and finally the crystal composition ,morphology and particle size of the obtained calcium carbonate were characterized through X-ray diffraction (XRD) ,scanning e-lectron microscope(SEM ) and laser particle size instrument .The results showed that the op-timal conditions for porous superfine calcium carbonate microspheres are as follow s :the so-lution concentration of CaCl2 was 0 .15 mol/L ,the amount of Tween-80 used in preparation was 4 mL ,the time of ultrasonic emulsification was 5 min ,the reaction time with stirring was 3 h .Under these conditions ,the particle size of porous superfine calcium carbonate ranged from 2 to 10 μm ,round ,and composed of the vaterite and calcite .

  17. Implantable porous gelatin microspheres sustained release of bFGF and improved its neuroprotective effect on rats after spinal cord injury

    Science.gov (United States)

    ZhuGe, Qi-Chuan; Shen, Bi-Xin; Jin, Bing-Hui; Huang, Jian-Ping; Wu, Ming-Ze; Fan, Lu-Xin; Zhao, Ying-Zheng; Xu, He-Lin

    2017-01-01

    In this study, porous gelatin microspheres (GMSs) were constructed to improve the neuroprotective effect of basic fibroblast growth factor (bFGF) on spinal cord injury. GMSs were prepared by a W/O emulsion template, followed by cross-linking, washing and drying. The particle sizes and surface porosity of the blank GMSs were carefully characterized by scan electronic microscopy. The blank GMSs have a mean particle size of 35μm and theirs surface was coarse and porous. bFGF was easily encapsulated inside the bulk GMSs through diffusion along the porous channel. 200μg of bFGF was completely encapsulated in 100mg of GMSs. The bFGF-loaded GMSs displayed a continuous drug release pattern without an obvious burst release over two weeks in vitro. Moreover, the therapeutic effects of bFGF-loaded GMSs were also evaluated in spinal cord injury rat model. After implantation of bFGF-loaded GMSs, the recovery of the motor function of SCI rats were evaluated by behavioral score and foot print experiment. The motor function of SCI rats treated with bFGF-loaded GMSs was more obvious than that treated with free bFGF solution (P<0.05). At the 28th days after treatment, rats were sacrificed and the injured spinal were removed for histopathological and apoptosis examination. Compared with treatment with free bFGF solution, treatment with bFGF-loaded GMSs resulted in a less necrosis, less infiltration of leukocytes, and a reduced the cavity ratio and less apoptotic cells in injured spinal(P<0.01), indicating its better therapeutic effect. Implantable porous GMSs may be a potential carrier to deliver bFGF for therapy of spinal cord injury. PMID:28291798

  18. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects

    Directory of Open Access Journals (Sweden)

    Xiong L

    2015-01-01

    Full Text Available Long Xiong,1 Jianhua Zeng,1 Aihua Yao,2 Qiquan Tu,3 Jingtang Li,1 Liang Yan,4 Zhiming Tang1 1Department of Osteology, People’s Hospital of Jiangxi Province, Nanchang, Jiangxi, People’s Republic of China; 2School of Materials Science and Engineering, Tongji University, Shanghai, People’s Republic of China; 3Department of Osteology, People’s Hospital of Jiujiang County, Jiujiang, Jiangxi, People’s Republic of China; 4Department of Osteology, The Third Hospital of Nanchang City, Nanchang, Jiangxi, People’s Republic of China Abstract: The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2, a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 µm with a core (60±18 µm and a mesoporous shell (180±42 m2/g surface area were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 µg/mg. There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option

  19. 光致变色多孔聚苯乙烯功能微球的制备和性能%Preparation of functionalized porous photochromic polystyrene microspheres and their performance

    Institute of Scientific and Technical Information of China (English)

    孙静; 裴广玲

    2011-01-01

    Porous cross-linked polystyrene microspheres were prepared by disperse polymerization in the presence of toluene/heptane as pore-forming agents.The effects of monomer, initiating agent, stabilizer, and cross-linker on the average size of the microspheres were investigated, and the photochromic performance of the porous polystyrene microspheres after adsorbing photochromic materials at ambient temperature and pressure was primarily evaluated.Results indicate that the porous polystyrene microspheres obtained under the optimized conditions have an average grain size of 1 μm.After adsorbing photochromic materials, the porous microspheres were able to rapidly reverse color under ultraviolet or sun light irradiation.Besides, the porous photochromic polystyrene microspheres could be fabricated into photochromic materials by using blending or coating technology; and it was feasible to improve their long lasting discoloring performance by surface-capping.%以甲苯/庚烷为致孔剂,利用分散聚合技术制备了多孔交联聚苯乙烯微球.研究了聚合单体、引发剂、稳定剂、交联剂等对微球平均粒径的影响,并初步评价了其在常温常压下吸附光致变色材料后的光致变色性能.结果表明,在最佳条件下制得的多孔聚合物微球平均粒径为1 μm;吸附光致变色材料后,其在紫外或日光照射下具有快速可逆的光致变色功能.利用共混或涂层技术可以将光致变色微球制备成光致变色材料;通过对变色微球进行表面包覆,可进一步提高其变色持久性.

  20. Synthesis of porous MnCo2O4microspheres with yolk–shell structure induced by concentration gradient and the effect on their performance in electrochemical energy storage

    DEFF Research Database (Denmark)

    Huang, Guoyong; Yang, Yue; Sun, Hongyu

    2016-01-01

    In this study, novel spherical yolk–shell MnCo2O4 powders with concentration gradient have been synthesized. The porous microspheres with yolk–shell structure (2.00–3.00 μm in average diameter, ∼200 nm in thickness of shell) are built up by irregular nanoparticles attached to each other. It is sh......In this study, novel spherical yolk–shell MnCo2O4 powders with concentration gradient have been synthesized. The porous microspheres with yolk–shell structure (2.00–3.00 μm in average diameter, ∼200 nm in thickness of shell) are built up by irregular nanoparticles attached to each other...

  1. Large area laser surface micro/nanopatterning by contact microsphere lens arrays

    NARCIS (Netherlands)

    Sedao, X.; Derrien, T.J.Y.; Romer, G.R.B.E.; Pathiraj, B.; Huis in 't veld, A.J.

    2013-01-01

    Laser surface micro/nanopatterning by particle lens arrays is a well-known technique. Enhanced optical fields can be achieved on a substrate when a laser beam passes through a self-assembled monolayer of silica microspheres placed on the substrate. This enhanced optical field is responsible for abla

  2. Large area laser surface micro/nanopatterning by contact microsphere lens arrays

    NARCIS (Netherlands)

    Sedao, X.; Derrien, T.J.Y.; Romer, G.R.B.E.; Pathiraj, B.; Huis in 't veld, A.J.

    2013-01-01

    Laser surface micro/nanopatterning by particle lens arrays is a well-known technique. Enhanced optical fields can be achieved on a substrate when a laser beam passes through a self-assembled monolayer of silica microspheres placed on the substrate. This enhanced optical field is responsible for

  3. Calcium carbonate microspheres as carriers for the anticancer drug camptothecin

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Neng [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Department of Bio-pharmaceutical Engineering, School of Chemical Engineering, Sichuan University, Chengdu ,610065 (China); Yin, Huabing, E-mail: huabing.yin@glasgow.ac.uk [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); Ji, Bozhi; Klauke, Norbert; Glidle, Andrew [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); Zhang, Yongkui; Song, Hang [Department of Bio-pharmaceutical Engineering, School of Chemical Engineering, Sichuan University, Chengdu ,610065 (China); Cai, Lulu; Ma, Liang; Wang, Guangcheng [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Chen, Lijuan, E-mail: lijuan17@hotmail.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Wang, Wenwen [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China)

    2012-12-01

    Biogenic calcium carbonate has come to the attention of many researchers as a promising drug delivery system due to its safety, pH sensitivity and the large volume of information already in existence on its medical use. In this study, we employed bovine serum albumin (BSA) as an additive to synthesize a series of porous calcium carbonate microspheres (CCMS). These spheres, identified as vaterite, are stable both in aqueous solutions and organic solvents. Camptothecin, an effective anticancer agent, was loaded into the CCMS by simple diffusion and adsorption. The camptothecin loaded CCMS showed sustained cell growth inhibitory activity and a pH dependent release of camptothecin. With a few hours, the release is negligible under physiological conditions (pH = 7.4) but almost complete at pH 4 to 6 (i.e. pHs found in lysosomes and solid tumor tissue respectively). These findings suggest that porous, biogenic calcium carbonate microspheres could be promising carriers for the safe and efficient delivery of anticancer drugs of low aqueous solubility. - Highlights: Black-Right-Pointing-Pointer BSA-doped calcium carbonate microspheres with porous structure were prepared. Black-Right-Pointing-Pointer Camptothecin was encapsulated in the spherical microparticles with encapsulation efficiency up to 11%. Black-Right-Pointing-Pointer The release of encapsulated camptothecin is pH dependent Black-Right-Pointing-Pointer In vitro studies showed an effective anticancer activity of the camptothecin- microspheres.

  4. Bimodal porous silica microspheres decorated with polydopamine nano-particles for the adsorption of methylene blue in fixed-bed columns.

    Science.gov (United States)

    Ataei-Germi, Taher; Nematollahzadeh, Ali

    2016-05-15

    Bimodal meso/macro-porous silica microspheres (MSM) were synthesized by a modified sol-emulsion-gel method and then the surface was coated with polydopamine (PDA) nano-particles of 39nm in size. Focusing on the encouraging properties of the synthesized adsorbent, such as high specific surface area (612.3m(2)g(-1), because of mesopores), fast mass transfer (0.9-2.67×10(-3)mLmin(-1)mg, because of macropores), and abundant "adhesive" functional groups of PDA, it was used for the removal of methylene blue (MB) from aqueous solution in a fixed-bed column. The effect of different parameters such as pH, initial concentration, and flow rate was studied. The results revealed that an appropriate sorption condition is an alkaline solution of MB (e.g., pH 10) at low flow rate (less than 5mLmin(-1)). Furthermore, the compatibility of the experimental data with mathematical models such as Thomas and Adams-Bohart was investigated. Both of the models showed a good agreement with the experimental data (R(2)=0.9954-0.9994), and could be applied for the prediction of the column properties and breakthrough curves. Regeneration of the column was performed by using HCl solution with a concentration of 0.1M as an eluent. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Adsorption Performance of Methyl Violet via α-Fe2O3@Porous Hollow Carbonaceous Microspheres and Its Effective Regeneration through a Fenton-Like Reaction

    Directory of Open Access Journals (Sweden)

    Zhiqing Tong

    2016-04-01

    Full Text Available α-Fe2O3@porous hollow carbonaceous microspheres (α-Fe2O3@PHCMs were prepared through a combination of hydrothermal and calcination method. The novel α-Fe2O3@PHCMs integrated the adsorptive and catalytic performances and served as an inexpensive adsorbent to rapidly remove cationic dye (methyl violet (MV from aqueous solution. Equilibrium studies indicated that the dye molecules obeyed Langmuir type of adsorption with the calculated maximum adsorption capacity of 539.8 mg∙g−1 at 313.15 K. Kinetic data were better described by pseudo-second-order model and the thermodynamic studies illustrated that MV adsorption onto the composite was spontaneous, endothermic and occurred by physisorption. The Fenton-like process was found to be effective for the regeneration of the spent α-Fe2O3@PHCMs. The regeneration efficiency, as high as 88.0%, was still maintained after three consecutive adsorption-regeneration cycles. FTIR and XRD characterizations of the composite before and after adsorption-regeneration treatment showed that the Fenton-like process did not cause serious damage to the structure of composites.

  6. A highly porous metal-organic framework for large organic molecule capture and chromatographic separation.

    Science.gov (United States)

    Li, Pei-Zhou; Su, Jie; Liang, Jie; Liu, Jia; Zhang, Yuanyuan; Chen, Hongzhong; Zhao, Yanli

    2017-03-25

    A highly porous metal-organic framework (MOF) with large pores was successfully obtained via solvothermal assembly of a "click"-extended tricarboxylate ligand and Zn(ii) ions. The inherent feature of large-molecule accessible pores endows the MOF with a unique property for utilization toward large guest molecules.

  7. Mesochanneled hierarchically porous aluminosiloxane aerogel microspheres as a stable support for pH-responsive controlled drug release.

    Science.gov (United States)

    Vazhayal, Linsha; Talasila, Sindhoor; Abdul Azeez, Peer Mohamed; Solaiappan, Ananthakumar

    2014-09-10

    The molecular-scale self-assembly of a 3D aluminosiloxane (Al-O-Si) hybrid gel network was successfully performed via the cocondensation of hydrolyzed alumina (AlOOH) and (3-aminopropyl)trimethoxysilane (APS). It was transformed into a microspherical aerogel framework of Al-O-Si containing mesochannels with tunable hierarchically bimodal meso/macroporosities by a subcritical drying technique. Good homogeneity of AlOOH and APS brought during the synthesis guaranteed a uniform distribution of two metal oxides in a single body. A systematic characterization of the aerogel support was carried out using FTIR, SEM, TEM, nitrogen adsorption/desorption analysis, WAXS, SAXS, and ξ-potential measurement in order to explore the material for drug uptake and release. The drug loading and release capacity and chemical stability of an aluminosiloxane aerogel were studied using two nonsteroidal antiinflammatory drugs, ibuprofen and aspirin. A comprehensive evaluation of the aluminosiloxane aerogel with ordered mesoporous MCM-41 was also performed. Aerogel supports showed a high drug loading capacity and a pH-responsive controlled-release property compared to MCM-41. Meanwhile, kinetic modeling studies indicate that the drug releases with a zero-order profile following the Korsmeyer-Peppas model. The biocompatibility of aluminosiloxane aerogels was established via ex vivo and in vivo studies. We also outline the use of aluminosiloxane aerogel as a support for a possible 3D matrix for an osteoconductive structure for bone tissue engineering.

  8. 分散聚合法合成含有环氧基的无孔超顺磁性微球及其表征%Preparation and Characterization of Non-porous Superparamagnetic Microspheres with Epoxy Groups by Dispersion Polymerization

    Institute of Scientific and Technical Information of China (English)

    马志亚; 官月平; 刘先桥; 刘会洲

    2005-01-01

    Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3 O4) 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 have extensive potential uses in magnetic bioseparation and biotechnology.

  9. Porous nano-hydroxyapatite/collagen scaffold containing drug-loaded ADM-PLGA microspheres for bone cancer treatment.

    Science.gov (United States)

    Rong, Zi-Jie; Yang, Lian-Jun; Cai, Bao-Ta; Zhu, Li-Xin; Cao, Yan-Lin; Wu, Guo-Feng; Zhang, Zan-Jie

    2016-05-01

    To develop adriamycin (ADM)-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a porous nano-hydroxyapatite/collagen scaffold (ADM-PLGA-NHAC). To provide novel strategies for future treatment of osteosarcoma, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of ADM-PLGA-NHAC on the osteosarcoma MG63 cells, and its bone repair capacity, were investigated in vivo and in vitro. The PLGA copolymer was utilized as a drug carrier to deliver ADM-PLGA nanoparticles (ADM-PLGA-NP). Porous nano-hydroxyapatite and collagen were used to materials to produce the porous nano-hydroxyapatite/collagen scaffold (NHAC), into which the ADM-PLGA-NP was loaded. The performance of the drug-carrying scaffold was assessed using multiple techniques, including scanning electron microscopy and in vitro extended release. The antineoplastic activities of scaffold extracts on the human osteosarcoma MG63 cell line were evaluated in vitro using the cell counting kit-8 (CCK8) method and live-dead cell staining. The bone repair ability of the scaffold was assessed based on the establishment of a femoral condyle defect model in rabbits. ADM-PLGA-NHAC and NHAC were implanted into the rat muscle bag for immune response experiments. A tumor-bearing nude mice model was created, and the TUNEL and HE staining results were observed under optical microscopy to evaluate the antineoplastic activity and toxic side effects of the scaffold. The composite scaffold demonstrated extraordinary extended-release properties, and its extracts also exhibited significant inhibition of the growth of osteosarcoma MG63 cells. In the bone repair experiment, no significant difference was observed between ADM-PLGA-NHAC and NHAC by itself. In the immune response experiments, ADM-PLGA-NHAC exhibited remarkable biocompatibility. The in vivo antitumor experiment revealed that the implantation of ADM-PLGA-NHAC in the tumor resulted in a improved antineoplastic

  10. Research progress in preparation and modification of porous polymeric microspheres for pulmonary drug delivery%肺部给药用高分子多孔微球的制备及改性研究进展

    Institute of Scientific and Technical Information of China (English)

    朱利会; 陈爱政; 王士斌

    2014-01-01

    As a non-invasive administration method,pulmonary drug delivery displays a great potential in the inhalable delivery of protein and peptide. The porous polymeric microspheres are one of the most suitable carriers for pulmonary drug delivery,this article presents several traditional methods to prepare porous polymeric microspheres,and analyzes the pros and cons of these methods under different conditions in the first place. Then,aiming at those questions such as difficulty to achieve a controllable process,and low efficiency in encapsulating drugs,this article reviews the physical and chemical modification of the porous microspheres to obtain a higher performance by the researchers in recent years,and the advices for the existing problems are also proposed. Finally,the combination of different methods to prepare porous polymeric microspheres for pulmonary drug delivery and their potential applications in the field of biomedicine are prospected.%肺部给药作为一种非入侵式的给药方式,在蛋白质、多肽类药物的给药研究中具有很大的发展潜力。高分子多孔微球是最适合肺部给药的药物载体之一,本文首先阐述了高分子多孔微球的几种传统制备方法,分析了这些制备方法在不同的条件下存在的优点及缺点。随后本文针对传统的高分子多孔微球制备条件难以单独控制,药物不能有效包封等问题,对近年来研究者们为了提高多孔微球的性能对其进行的物理化学改性进行了综述并提出了观点。最后对肺部给药用高分子多孔微球不同的制备方法的相互结合以及在生物医学领域的应用价值进行了展望。

  11. Unexpected large room-temperature ferromagnetism in porous Cu{sub 2}O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xue [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Sun, Huiyuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Liu, Lihu; Jia, Xiaoxuan; Liu, Huiyuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China)

    2015-05-15

    Porous Cu{sub 2}O films have been fabricated on porous anodic alumina substrates using DC-reactive magnetron sputtering with pure Cu targets, and unexpectedly large room temperature ferromagnetism has been observed in the films. The maximum saturation magnetic moment along the out-of-plane direction was as high as 94 emu/cm{sup 3}. Photoluminescence spectra show that the ferromagnetism originates with oxygen vacancies. The ferromagnetism could be adjusted by changing the concentration of oxygen vacancies through annealing in an oxygen atmosphere. These observations suggest that the origin of the ferromagnetism is due to coupling between oxygen vacancies with local magnetic moments in the porous Cu{sub 2}O films, which can occur either directly through exchange interactions between oxygen vacancies, or through the mediation of conduction electrons. Such a ferromagnet without the presence of any ferromagnetic dopant may find applications in spintronic devices. - Highlights: • Porous Cu{sub 2}O films were deposited on porous anodic alumina (PAA) substrates. • Significant room-temperature ferromagnetism has been observed in porous Cu{sub 2}O films. • Ferromagnetism of Cu{sub 2}O films exhibited different magnetic signals with the field. • The saturation magnetization is 94 emu/cm{sup 3} with an out-of-plane.

  12. Large Frequency Range of Photonic Band Gaps on Porous Silicon Heterostructures for Infrared Applications

    CERN Document Server

    Manzanares-Martinez, J; Archuleta-Garcia, R; Moctezuma-Enriquez, D

    2010-01-01

    In this work we show theoretically that it is possible to design a large band gap in the infrared range using a one-dimensional Photonic Crystal heterostructure made of porous silicon. Stacking together multiple photonic crystal substructures of the same contrast index, but of different lattice periods, it is possible to broad the narrow forbidden band gap that can be reached by the low contrast index of the porous silicon multilayers. The main idea in this work is that we can construct a Giant Photonic Band Gap -as large as desired- by combining a tandem of photonic crystals substructures by using a simple analytical rule to determine the period of each substructure.

  13. Novel Au/La-SrTiO3 microspheres: superimposed effect of gold nanoparticles and lanthanum doping in photocatalysis.

    Science.gov (United States)

    Wang, Guannan; Wang, Pei; Luo, He-Kuan; Hor, T S Andy

    2014-07-01

    Novel multielement Au/La-SrTiO(3) microspheres were synthesized by a solvothermal method using monodisperse gold and La-SrTiO(3) nanocrystals as building blocks. The porous Au/La-SrTiO(3) microspheres had a large surface area of 94.6 m(2)  g(-1). The stable confined Au nanoparticles demonstrated strong surface plasmon resonance effect, leading to enhanced absorption in a broad UV/Vis/NIR range. Doping of rare-earth metal La also broadened the absorption band to the visible region. Both the conduction and valence bands of Au/La-SrTiO(3) microspheres thus show favorable potential for proton reduction under visible light. The superimposed effect of Au nanoparticles and La doping in Au/La-SrTiO(3) microspheres led to high photocurrent density in photoelectrochemical water splitting and good photocatalytic activity in photodegradation of rhodamine B. The photocatalytic activities are in the order of the following: Au/La-SrTiO(3) microspheres>Au/SrTiO(3) microspheres>La-SrTiO(3) microspheres>SrTiO(3) microspheres.

  14. Synthesis,characterization and decolorizing performance of porous ceria hollow microspheres%多孔氧化铈空心微球的合成、表征及其脱色性能

    Institute of Scientific and Technical Information of China (English)

    陈爱莲; 隆仁伟; 陆锦霞

    2011-01-01

    The porous ceria hollow microspheres with controlled shell thickness were synthesized by a simple polystyrene sphere template method using cerium nitrate as cerium resource, hexamethylenetetramine as precipitating agent. The microstructure and properties of the as-synthesized samples were characterized by XRD, TEM, FESEM, XPS and N2 adsorption-desorption. The decolorizing performance of the ceria hollow microspheres on methyl orange dye waster water was also investigated. The results indicate that the ceria hollow microspheres have porous structure with average pore diameter of 10 nm, sphere diameter of 200-250 nm and shell thickness of 10-30 nm, and the cell composes of CeO2 sphere with diameter of 5-10 nm. The decolorizing rate of methyl orange dye waster water treated by ceria hollow microspheres for 60 min can reach above 95%. This indicates that these porous ceria hollow materials have good decolorizing performance.%以聚苯乙烯微球为模板、六水硝酸亚铈为铈源、六亚甲基四胺为沉淀剂,制备不同壳厚的氧化铈空心微球;利用XRD、TEM、FESEM、XPS和氮气吸附一脱附等手段,对所制备样品的微观结构进行表征.将所制备的Ce02空心微球用于甲基橙模拟染料废水的脱色处理.结果表明:CeO2空心微球具有多孔结构,表面平均孔径约为10 nm,球径约为200~250 nm,壳厚约为10~30 nm,壳层是由粒径为5~10 nm的CeO2颗粒所组成;甲基橙溶液经CeO2空心微球处理60 min后,其脱色率可达95%以上,表现出良好的脱色性能.

  15. Production of large-scale, freestanding vanadium pentoxide nanobelt porous structures

    Science.gov (United States)

    Yun, Yong Ju; Kim, Byung Hoon; Hong, Won G.; Kim, Chang Hee; Kim, Yark Yeon; Jeong, Eun-Ju; Jang, Won Ick; Yu, Han Young

    2012-02-01

    Large-scale, freestanding, porous structures of vanadium pentoxide nanobelts (VPNs) were successfully prepared using the template-free freeze-drying method. The porous and multi-layered VPN macrostructures are composed of randomly oriented long nanobelts (over 100 μm) and their side length can be controlled up to a few tens of centimetres. Also, the bulk density and surface area of these macrostructures are 3-5 mg cm-3 and 40-80 m2 g-1, respectively, which are similar to those of the excellent adsorbents. In addition, the removal efficiency measurements of ammonia molecules revealed that the VPN porous structures can adsorb the ammonia molecules with the combinations of van der Waals forces and strong chemical bonding by functional groups on the VPN surface.

  16. Simple Synthesis of Molybdenum Disulfide/Reduced Graphene Oxide Composite Hollow Microspheres as Supercapacitor Electrode Material

    Directory of Open Access Journals (Sweden)

    Wei Xiao

    2016-09-01

    Full Text Available MoS2/RGO composite hollow microspheres were hydrothermally synthesized by using SiO2/GO microspheres as a template, which were obtained via the sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 microspheres. The structure, morphology, phase, and chemical composition of MoS2/RGO hollow microspheres were systematically investigated by a series of techniques such as FE-SEM, TEM, XRD, TGA, BET, and Raman characterizations, meanwhile, their electrochemical properties were carefully evaluated by CV, GCD, and EIS measurements. It was found that MoS2/RGO hollow microspheres possessed unique porous hollow architecture with high-level hierarchy and large specific surface area up to 63.7 m2·g−1. When used as supercapacitor electrode material, MoS2/RGO hollow microspheres delivered a maximum specific capacitance of 218.1 F·g−1 at the current density of 1 A·g−1, which was much higher than that of contrastive bare MoS2 microspheres developed in the present work and most of other reported MoS2-based materials. The enhancement of supercapacitive behaviors of MoS2/RGO hollow microspheres was likely due to the improved conductivity together with their distinct structure and morphology, which not only promoted the charge transport but also facilitated the electrolyte diffusion. Moreover, MoS2/RGO hollow microsphere electrode displayed satisfactory long-term stability with 91.8% retention of the initial capacitance after 1000 charge/discharge cycles at the current density of 3 A·g−1, showing excellent application potential.

  17. Synthesis of polyvinyl alcohol/cellulose nanofibril hybrid aerogel microspheres and their use as oil/solvent superabsorbents.

    Science.gov (United States)

    Zhai, Tianliang; Zheng, Qifeng; Cai, Zhiyong; Xia, Hesheng; Gong, Shaoqin

    2016-09-05

    Superhydrophobic and crosslinked poly(vinyl alcohol) (PVA)/cellulose nanofibril (CNF) aerogel microspheres were prepared via a combination of the water-in-oil (W/O) emulsification process with the freeze-drying process, followed by thermal chemical vapor deposition of methyltrichlorosilane. The oil phase and the cooling agent were judiciously selected to ensure that the frozen ice microspheres can be easily separated from the emulsion system. The silanized microspheres were highly porous with a bulk density ranging from 4.66 to 16.54mg/cm(3). The effects of the solution pH, stirring rate, and emulsifier concentration on the morphology and microstructure of the aerogel microspheres were studied. The highly porous structure of the ultralight aerogel microspheres demonstrated an ultrahigh crude oil absorption capacity (up to 116 times its own weight). This study provides a novel approach for the large-scale preparation of polymeric aerogel microspheres with well-controlled particle sizes that can be used for various applications including oil and chemical spill/leak clean-up.

  18. A Feasibility Study on Operating Large Scale Compressed Air Energy Storage in Porous Formations

    Science.gov (United States)

    Wang, B.; Pfeiffer, W. T.; Li, D.; Bauer, S.

    2015-12-01

    Compressed air energy storage (CAES) in porous formations has been considered as one promising option of large scale energy storage for decades. This study, hereby, aims at analyzing the feasibility of operating large scale CAES in porous formations and evaluating the performance of underground porous gas reservoirs. To address these issues quantitatively, a hypothetic CAES scenario with a typical anticline structure in northern Germany was numerically simulated. Because of the rapid growth in photovoltaics, the period of extraction in a daily cycle was set to the early morning and the late afternoon in order to bypass the massive solar energy production around noon. The gas turbine scenario was defined referring to the specifications of the Huntorf CAES power plant. The numerical simulations involved two stages, i.e. initial fill and cyclic operation, and both were carried out using the Eclipse E300 simulator (Schlumberger). Pressure loss in the gas wells was post analyzed using an analytical solution. The exergy concept was applied to evaluate the potential energy amount stored in the specific porous formation. The simulation results show that porous formations prove to be a feasible solution of large scale CAES. The initial fill with shut-in periods determines the spatial distribution of the gas phase and helps to achieve higher gas saturation around the wells, and thus higher deliverability. The performance evaluation shows that the overall exergy flow of stored compressed air is also determined by the permeability, which directly affects the deliverability of the gas reservoir and thus the number of wells required.

  19. Tracking the effect of microspheres size on the drug release from a microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot in vitro and in vivo.

    Science.gov (United States)

    Lin, Xia; Wang, Jing; Xu, Yuhong; Tang, Xing; Chen, Jian; Zhang, Yu; Zhang, Yan; Yang, Ziyi

    2016-09-01

    The effects of particle size of microspheres on the drug release from a microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot (m-SAIB) was investigated to develop a long-term sustained release drug delivery system with low burst release both in vitro and in vivo. A model drug, risperidone, was first encapsulated into PLGA microspheres with different particle sizes using conventional emulsification and membrane emulsification methods. The m-SAIB was prepared by dispersing the risperidone-microspheres in the SAIB depot. The drug release from m-SAIB was double controlled by the drug diffusion from the microspheres into SAIB matrix and the drug diffusion from the SAIB matrix into the medium. Large microspheres (18.95 ± 18.88 µm) prepared by the conventional homogenization method exhibited porous interior structure, which contributed to the increased drug diffusion rate from microspheres into SAIB matrix. Consequently, m-SAIB containing such microspheres showed rapid initial drug release (Cmax = 110.1 ±54.2 ng/ml) and subsequent slow drug release (Cs(4-54d)= 2.7 ± 0.8 ng/ml) in vivo. Small microspheres (5.91 ± 2.24 µm) showed dense interior structure with a decreased drug diffusion rate from microspheres into SAIB matrix. The initial drug release from the corresponding m-SAIB was significantly decreased (Cmax = 40.9 ± 13.7 ng/ml), whereas the drug release rate from 4 to 54 d was increased (Cs(4-54d)=4.1 ± 1.0 ng/ml). By further decreasing the size of microspheres to 3.38 ± 0.70 µm, the drug diffusion surface area was increased, which subsequently increased the drug release from the m-SAIB. These results demonstrate that drug release from the m-SAIB can be tailored by varying the size of microspheres to reduce the in vivo burst release of SAIB system alone.

  20. Large-scale fabrication of In2S3 porous films via one-step hydrothermal process.

    Science.gov (United States)

    Chen, Fei; Deng, Dan; Lei, Yinlin

    2013-10-01

    Large-scale indium sulfide (In2S3) porous films were fabricated via a facile one-step and non-template hydrothermal process using L-cysteine as a capping agent. The impact of reaction conditions such as reaction time, temperatures, and capping agents on the synthesis of the In2S3 porous films were studied. The morphology, structure, and phase composition of In2S3 porous films were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The formation process and the optical property of the In2S3 porous films were also evaluated.

  1. Porous microwells for geometry-selective, large-scale microparticle arrays

    Science.gov (United States)

    Kim, Jae Jung; Bong, Ki Wan; Reátegui, Eduardo; Irimia, Daniel; Doyle, Patrick S.

    2017-01-01

    Large-scale microparticle arrays (LSMAs) are key for material science and bioengineering applications. However, previous approaches suffer from trade-offs between scalability, precision, specificity and versatility. Here, we present a porous microwell-based approach to create large-scale microparticle arrays with complex motifs. Microparticles are guided to and pushed into microwells by fluid flow through small open pores at the bottom of the porous well arrays. A scaling theory allows for the rational design of LSMAs to sort and array particles on the basis of their size, shape, or modulus. Sequential particle assembly allows for proximal and nested particle arrangements, as well as particle recollection and pattern transfer. We demonstrate the capabilities of the approach by means of three applications: high-throughput single-cell arrays; microenvironment fabrication for neutrophil chemotaxis; and complex, covert tags by the transfer of an upconversion nanocrystal-laden LSMA.

  2. Polyacrolein microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor)

    1987-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  3. Modelling large-deforming fluid-saturated porous media using an Eulerian incremental formulation

    CERN Document Server

    Rohan, Eduard

    2016-01-01

    The paper deals with modelling fluid saturated porous media subject to large deformation. An Eulerian incremental formulation is derived using the problem imposed in the spatial configuration in terms of the equilibrium equation and the mass conservation. Perturbation of the hyperelastic porous medium is described by the Biot model which involves poroelastic coefficients and the permeability governing the Darcy flow. Using the material derivative with respect to a convection velocity field we obtain the rate formulation which allows for linearization of the residuum function. For a given time discretization with backward finite difference approximation of the time derivatives, two incremental problems are obtained which constitute the predictor and corrector steps of the implicit time-integration scheme. Conforming mixed finite element approximation in space is used. Validation of the numerical model implemented in the SfePy code is reported for an isotropic medium with a hyperelastic solid phase. The propose...

  4. A reproducible accelerated in vitro release testing method for PLGA microspheres.

    Science.gov (United States)

    Shen, Jie; Lee, Kyulim; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

    2016-02-10

    The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting PLGA microspheres with inner structure/porosity differences. Risperidone was chosen as a model drug. Qualitatively and quantitatively equivalent PLGA microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared risperidone microspheres was performed using the most common in vitro release methods (i.e., sample-and-separate and flow through) for this type of product. The obtained compositionally equivalent risperidone microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous risperidone microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate risperidone microsphere formulations with differences in porosity under real-time (37 °C) and accelerated (45 °C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous risperidone microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting PLGA microspheres (even with porous structures).

  5. Superficially porous particles with 1000Å pores for large biomolecule high performance liquid chromatography and polymer size exclusion chromatography.

    Science.gov (United States)

    Wagner, Brian M; Schuster, Stephanie A; Boyes, Barry E; Shields, Taylor J; Miles, William L; Haynes, Mark J; Moran, Robert E; Kirkland, Joseph J; Schure, Mark R

    2017-03-17

    To facilitate mass transport and column efficiency, solutes must have free access to particle pores to facilitate interactions with the stationary phase. To ensure this feature, particles should be used for HPLC separations which have pores sufficiently large to accommodate the solute without restricted diffusion. This paper describes the design and properties of superficially porous (also called Fused-Core(®), core shell or porous shell) particles with very large (1000Å) pores specifically developed for separating very large biomolecules and polymers. Separations of DNA fragments, monoclonal antibodies, large proteins and large polystyrene standards are used to illustrate the utility of these particles for efficient, high-resolution applications.

  6. PtNi nanoparticles embedded in porous silica microspheres as highly active catalysts for p-nitrophenol hydrogenation to p-aminophenol

    Indian Academy of Sciences (India)

    HUIJUAN GUAN; CONG CHAO; YANJIE LU; HUISHAN SHANG; YAFEI ZHAO; SIGUO YUAN; BING ZHANG

    2016-09-01

    Supported Pt-based alloy nanoparticles have attracted greater attention in catalysis due to their high activity, reduced cost, and easy recycling in chemical reactions. In this work, mesoporous SiO₂ microspheres were employed as support to immobilize PtNi alloy nanocatalysts with different mass ratios of Pt and Ni (1:0, 3:1, 1:1, 1:3 and 0:1) by a facile in situ one-step reduction in the absence of any capping agent. SEM, EDS, TEM, FTIR, XRD, ICP-AES, XPS and nitrogen adsorption/desorption analysis were employed to systematically investigate the morphology and structure of the obtained SiO2 microspheres and SiO₂/PtNi nanocatalysts. Results show that uniform PtNi nanoparticles can be homogeneously and firmly embedded into the surface of SiO₂ microspheres. When the as-prepared SiO₂/PtNi nanocatalysts were used in the reduction process of pnitrophenol to p-aminophenol, the nanocatalyst with Pt and Ni mass ratio of 1:3 showed the highest catalytic activity (TOF of 5.35 × 10¹⁸ molecules·g⁻¹·s⁻¹) and could transform p-nitrophenol to p-aminophenol completely within 5 min. The SiO₂/PtNi nanocatalyst can also maintain high catalytic activity in the fourth cycle, implying its excellent stability during catalysis.

  7. Comparison of transport and attachment behaviors of Cryptosporidium parvum oocysts and oocyst-sized microspheres being advected through three minerologically different granular porous media.

    Science.gov (United States)

    Mohanram, Arvind; Ray, Chittaranjan; Harvey, Ronald W; Metge, David W; Ryan, Joseph N; Chorover, Jon; Eberl, D D

    2010-10-01

    In order to gain more information about the fate of Cryptosporidium parvum oocysts in tropical volcanic soils, the transport and attachment behaviors of oocysts and oocyst-sized polystyrene microspheres were studied in the presence of two soils. These soils were chosen because of their differing chemical and physical properties, i.e., an organic-rich (43-46% by mass) volcanic ash-derived soil from the island of Hawaii, and a red, iron (22-29% by mass), aluminum (29-45% by mass), and clay-rich (68-76% by mass) volcanic soil from the island of Oahu. A third agricultural soil, an organic- (13% by mass) and quartz-rich (40% by mass) soil from Illinois, was included for reference. In 10-cm long flow-through columns, oocysts and microspheres advecting through the red volcanic soil were almost completely (98% and 99%) immobilized. The modest breakthrough resulted from preferential flow-path structure inadvertently created by soil-particle aggregation during the re-wetting process. Although a high (99%) removal of oocysts and microsphere within the volcanic ash soil occurred initially, further examination revealed that transport was merely retarded because of highly reversible interactions with grain surfaces. Judging from the slope of the substantive and protracted tail of the breakthrough curve for the 1.8-μm microspheres, almost all (>99%) predictably would be recovered within ∼4000 pore volumes. This suggests that once contaminated, the volcanic ash soil could serve as a reservoir for subsequent contamination of groundwater, at least for pathogens of similar size or smaller. Because of the highly reversible nature of organic colloid immobilization in this soil type, C. parvum could contaminate surface water should overland flow during heavy precipitation events pick up near-surface grains to which they are attached. Surprisingly, oocyst and microsphere attachment to the reference soil from Illinois appeared to be at least as sensitive to changes in pH as was

  8. Comparison of transport and attachment behaviors of Cryptosporidium parvum oocysts and oocyst-sized microspheres being advected through three minerologically different granular porous media

    Science.gov (United States)

    Mohanram, A.; Ray, C.; Harvey, R.W.; Metge, D.W.; Ryan, J.N.; Chorover, J.; Eberl, D.D.

    2010-01-01

    In order to gain more information about the fate of Cryptosporidium parvum oocysts in tropical volcanic soils, the transport and attachment behaviors of oocysts and oocyst-sized polystyrene microspheres were studied in the presence of two soils. These soils were chosen because of their differing chemical and physical properties, i.e., an organic-rich (43-46% by mass) volcanic ash-derived soil from the island of Hawaii, and a red, iron (22-29% by mass), aluminum (29-45% by mass), and clay-rich (68-76% by mass) volcanic soil from the island of Oahu. A third agricultural soil, an organic- (13% by mass) and quartz-rich (40% by mass) soil from Illinois, was included for reference. In 10-cm long flow-through columns, oocysts and microspheres advecting through the red volcanic soil were almost completely (98% and 99%) immobilized. The modest breakthrough resulted from preferential flow-path structure inadvertently created by soil-particle aggregation during the re-wetting process. Although a high (99%) removal of oocysts and microsphere within the volcanic ash soil occurred initially, further examination revealed that transport was merely retarded because of highly reversible interactions with grain surfaces. Judging from the slope of the substantive and protracted tail of the breakthrough curve for the 1.8-??m microspheres, almost all (>99%) predictably would be recovered within ~4000 pore volumes. This suggests that once contaminated, the volcanic ash soil could serve as a reservoir for subsequent contamination of groundwater, at least for pathogens of similar size or smaller. Because of the highly reversible nature of organic colloid immobilization in this soil type, C. parvum could contaminate surface water should overland flow during heavy precipitation events pick up near-surface grains to which they are attached. Surprisingly, oocyst and microsphere attachment to the reference soil from Illinois appeared to be at least as sensitive to changes in pH as was observed

  9. Simulation of incompressible two-phase flow in porous media with large timesteps

    CERN Document Server

    Cogswell, Daniel A

    2016-01-01

    The equations for the flow of two immiscible, incompressible fluid phases in porous media are recast as a gradient flow using the phase-field method, and a convex energy splitting scheme is applied to enable unconditionally large timesteps. The model accurately reproduces the Buckley-Leverett solution and is robust with respect to high degrees of heterogeneity in permeability and viscosity. By using the phase-field formulation as a homotopy map, the underlying hyperbolic flow equations can be solved directly with large timesteps. For a heterogeneous test problem, the new formulation allows the timestep to be increased by more than four orders of magnitude relative to the traditional formulation while maintaining both stability and accuracy.

  10. Lumbar interbody fusion with porous biphasic calcium phosphate enhanced by recombinant bone morphogenetic protein-2/silk fibroin sustained-released microsphere: an experimental study on sheep model.

    Science.gov (United States)

    Chen, Liang; Liu, Hai-Long; Gu, Yong; Feng, Yu; Yang, Hui-Lin

    2015-03-01

    Biphasic calcium phosphate (BCP) has been investigated extensively as a bone substitute nowadays. However, the bone formation capacity of BCP is limited owing to lack of osteoinduction. Silk fibroin (SF) has a structure similar to type I collagen, and could be developed to a microsphere for the sustained-release of rhBMP-2. In our previous report, bioactivity of BCP could be enhanced by rhBMP-2/SF microsphere (containing 0.5 µg rhBMP-2) in vitro. However, the bone regeneration performance of the composite in vivo was not investigated. Thus, the purpose of this study was to evaluate the efficacy of BCP/rhBMP-2/SF in a sheep lumbar fusion model. A BCP and rhBMP-2/SF microsphere was developed, and then was integrated into a BCP/rhBMP-2/SF composite. BCP, BCP/rhBMP-2 and BCP/rhBMP-2/SF were implanted randomly into the disc spaces of 30 sheep at the levels of L1/2, L3/4 and L5/6. After sacrificed, the fusion segments were evaluated by manual palpation, CT scan, biomechanical testing and histology at 3 and 6 months, respectively. The composite demonstrated a burst-release of rhBMP-2 (39.1 ± 2.8 %) on the initial 4 days and a sustained-release (accumulative 81.3 ± 4.9 %) for more than 28 days. The fusion rates, semi-quantitative CT scores, fusion stiffness in bending in all directions and histologic scores of BCP/rhBMP-2/SF were significantly greater than BCP and BCP/rhBMP-2 at each time point, respectively (P sheep using BCP constructs.

  11. Fluorescent microspheres

    Science.gov (United States)

    Rembaum, A.

    1978-01-01

    Latex particles with attached antibodies have potential biochemical and environmental applications. Human red blood cells and lymphocytes have been labeled with fluorescent microspheres by either direct or indirect immunological technique. Immunolatex spheres can also be used for detecting and localizing specific cell surface receptors. Hormones and toxins may also be bondable.

  12. Porous medium convection at large Rayleigh number: Studies of coherent structure, transport, and reduced dynamics

    Science.gov (United States)

    Wen, Baole

    Buoyancy-driven convection in fluid-saturated porous media is a key environmental and technological process, with applications ranging from carbon dioxide storage in terrestrial aquifers to the design of compact heat exchangers. Porous medium convection is also a paradigm for forced-dissipative infinite-dimensional dynamical systems, exhibiting spatiotemporally chaotic dynamics if not "true" turbulence. The objective of this dissertation research is to quantitatively characterize the dynamics and heat transport in two-dimensional horizontal and inclined porous medium convection between isothermal plane parallel boundaries at asymptotically large values of the Rayleigh number Ra by investigating the emergent, quasi-coherent flow. This investigation employs a complement of direct numerical simulations (DNS), secondary stability and dynamical systems theory, and variational analysis. The DNS confirm the remarkable tendency for the interior flow to self-organize into closely-spaced columnar plumes at sufficiently large Ra (up to Ra ≃ 105), with more complex spatiotemporal features being confined to boundary layers near the heated and cooled walls. The relatively simple form of the interior flow motivates investigation of unstable steady and time-periodic convective states at large Ra as a function of the domain aspect ratio L. To gain insight into the development of spatiotemporally chaotic convection, the (secondary) stability of these fully nonlinear states to small-amplitude disturbances is investigated using a spatial Floquet analysis. The results indicate that there exist two distinct modes of instability at large Ra: a bulk instability mode and a wall instability mode. The former usually is excited by long-wavelength disturbances and is generally much weaker than the latter. DNS, strategically initialized to investigate the fully nonlinear evolution of the most dangerous secondary instability modes, suggest that the (long time) mean inter-plume spacing in

  13. Strong infrared photoluminescence in highly porous layers of large faceted Si crystalline nanoparticles

    Science.gov (United States)

    de Jong, E. M. L. D; Mannino, G.; Alberti, A.; Ruggeri, R.; Italia, M.; Zontone, F.; Chushkin, Y.; Pennisi, A. R.; Gregorkiewicz, T.; Faraci, G.

    2016-01-01

    Almost all physical processes in solids are influenced by phonons, but their effect is frequently overlooked. In this paper, we investigate the photoluminescence of large silicon nanoparticles (approximately 100 nm size, synthesized by chemical vapor deposition) in the visible to the infrared detection range. We find that upon increasing laser irradiance, an enormous photoluminescence emission band appears in the infrared. Its intensity exhibits a superlinear power dependence, increasing over four orders of magnitude in the investigated pump power range. Particles of different sizes as well as different shapes in porous layers are investigated. The results are discussed taking into account the efficient generation of phonons under high-power pumping, and the reduced capability, porosity dependent, of the silicon nanoparticles to exchange energy with each other and with the substrate. Our findings are relevant for heat management strategies in silicon. PMID:27216452

  14. POE/PLGA composite microspheres: formation and in vitro behavior of double walled microspheres.

    Science.gov (United States)

    Yang, Yi-Yan; Shi, Meng; Goh, Suat-Hong; Moochhala, Shabbir M; Ng, Steve; Heller, Jorge

    2003-03-07

    The poly(ortho ester) (POE) and poly(D,L-lactide-co-glycolide) 50:50 (PLGA) composite microspheres were fabricated by a water-in-oil-in-water (w/o/w) double emulsion process. The morphology of the composite microspheres varied depending on POE content. When the POE content was 50, 60 or 70% in weight, the double walled microspheres with a dense core of POE and a porous shell of PLGA were formed. The formation of the double walled POE/PLGA microspheres was analysed. Their in vitro degradation behavior was characterized by scanning electron microscopy, gel permeation chromatography, Fourier-transform infrared microscopy and nuclear magnetic resonance spectroscopy (NMR). It was found that compared to the neat POE or PLGA microspheres, distinct degradation mechanism was achieved in the double walled POE/PLGA microspheres system. The degradation of the POE core was accelerated due to the acidic microenvironment produced by the hydrolysis of the outer PLGA layer. The formation of hollow microspheres became pronounced after the first week in vitro. 1H NMR spectra showed that the POE core was completely degraded after 4 weeks. On the other hand, the outer PLGA layer experienced slightly retarded degradation after the POE core disappeared. PLGA in the double walled microspheres kept more than 32% of its initial molecular weight over a period of 7 weeks.

  15. A self-cleaning porous TiO2-Ag core-shell nanocomposite material for surface-enhanced Raman scattering.

    Science.gov (United States)

    Zou, Xiaoxin; Silva, Rafael; Huang, Xiaoxi; Al-Sharab, Jafar F; Asefa, Tewodros

    2013-01-14

    A porous TiO(2)-Ag core-shell nanocomposite material with a large surface area was synthesized by in situ hydrolyzation of Sn(2+)-grafted titanium glycolate microspheres in the presence of Ag(+) ions. The as-prepared nanocomposite material was shown to serve as an efficient self-cleaning surface-enhanced Raman scattering (SERS) substrate.

  16. Synthesis of TiO2/Poly(styrene-co-divinybenzene)Nanocomposite Microspheres by Grafting Copolymerization

    Institute of Scientific and Technical Information of China (English)

    LI Sen; WANG Kuan; CHENG Jiang; WEN Xiu-Fang; PI Pi-Hui; YANG Zhuo-Ru; LI Zhi-Ying

    2008-01-01

    Porous and nonporous nanocomposite microspheres were successfully prepared by grafting titania (TiO2) particles to poly(styrene-co-divinylbenzene) microsphere involving silane coupling agent 3-glycidoxypropyltri-methoxysilane (KH560), styrene and maleic anhydride as coupling agents. The effects of KH560 and styrene on the dispersion and amount of grafted-titania on the surface of the microsphere (nonporous) as well as the effect of porous properly of the supporting microsphere on the amount of grafted-TiO2 within the microsphere (porous) were investigated. The results indicated that both KH560 and styrene could enhance the stability and dispersion of TiO2 particles attached to the surface of the microsphere producing grain size with diameter in the range of 30-80 nm. With nonporous microsphere styrene also increased the amount of grafted-TiO2 particles on the microsphere from 10.4% to 20.4% as revealed by TGA. Porous nanoeomposite microspheres with mean pore size of 136 nm could accommodate more TiO2 particles larger than either nonporous nanocomposite or porous nancomposite with mean pore size of 31 nm, yielding maximum of 26% by weight of grafted-TiO2.

  17. 聚羟基脂肪酸酯多孔微球的制备及扫描电镜观察%Preparation of porous polyhydroxyalkanoates microsphere and determination by scanning electron microscopy

    Institute of Scientific and Technical Information of China (English)

    林月娟; 魏岱旭; 孙立志; 方国

    2011-01-01

    聚羟基脂肪酸酯材料是一种具有良好生物相容性和生物可降解性的生物材料,可用于制备成各种不同形式的多孔支架运用于组织工程.本文用碳酸氢铵为气体致孔剂,采用双乳液溶剂挥发法,制备出多孔的聚羟基脂肪酸酯膜和微球,并通过扫描电子显微镜对这两种多孔材料的表面和剖面结构进行观察,探讨不同的制备条件对多孔材料的影响.%Objective Polyhydroxyalkanoates ( PHA) is a biomaterial with good biodegradability and bio-compatibility , and is prepared into different forms of scaffold and applied in tissue engineering. To fabricate porous PHA microspheres through a modified water-in-oil-in-water (W1/0/W2) double emulsion solvent evaporation method with ammonium bicarbonate, and to analyze the influence of different factors through detecting their surface and section structure by scanning electron microscopy.

  18. 多孔性再生纤维素磁性微球的制备及性质%Preparation and properties analysis of porous magnetic microspheres from regenerated cellulose

    Institute of Scientific and Technical Information of China (English)

    谷军; 吴伟兵; 王飞; 龚木荣; 景宜; 戴红旗

    2012-01-01

    利用绿色环保的碱-尿素-水溶剂体系制备纤维素溶液,采用反相悬浮法制备纤维素微球,并通过原位复合法工艺对纤维素微球进行纳米磁性功能化负载.结果表明,随着油水比不断增大,微球粒径逐渐减小,制备的再生纤维素微球比表面积超过30m2/g,孔度超过90%,吸水性强,含水率超过85%.通过FTIR、XRD和SEM研究发现原位复合法可成功地生成Fe304纳米粒子,并在纤维素微球中形成有效负载,且制备的纤维复合微球保留了良好的球形结构和多孔性,并具有超顺磁性.%The natural cellulose now has become one of the research hotspats in the water treatment research field for its excellent performance. Natural cellulose was directly dissolved in environmental-friendly alkali/carbamide/water solvent system. Reversed-phase suspension technique was used to regenerate cellulose microspheres, they were further magnetically functionalized through in-situ synthesis method. The results showed that there was a decrease in the diameters of the cellulose microspheres with an increase of the oil/water ratio. The prepared cellulose microspheres had large specific surface area ( >30 mVg) , good porosity ( >90 % ) , and high water content ( > 85 % ). Based on the results of FTIR, XRD and SEM, Fe3O4 nanoparticles were successfully formed and loaded in the cellulose microspheree. The cellulose composites preserved good orbicular shape, porosity and superparamagnetism. This type of cellulose microspheres material possessed potential application in the water treatment field.

  19. Continuous Purification of Colloidal Quantum Dots in Large-Scale Using Porous Electrodes in Flow Channel

    Science.gov (United States)

    Lim, Hosub; Woo, Ju Young; Lee, Doh C.; Lee, Jinkee; Jeong, Sohee; Kim, Duckjong

    2017-01-01

    Colloidal quantum dots (QDs) afford huge potential in numerous applications owing to their excellent optical and electronic properties. After the synthesis of QDs, separating QDs from unreacted impurities in large scale is one of the biggest issues to achieve scalable and high performance optoelectronic applications. Thus far, however, continuous purification method, which is essential for mass production, has rarely been reported. In this study, we developed a new continuous purification process that is suitable to the mass production of high-quality QDs. As-synthesized QDs are driven by electrophoresis in a flow channel and captured by porous electrodes and finally separated from the unreacted impurities. Nuclear magnetic resonance and ultraviolet/visible/near-infrared absorption spectroscopic data clearly showed that the impurities were efficiently removed from QDs with the purification yield, defined as the ratio of the mass of purified QDs to that of QDs in the crude solution, up to 87%. Also, we could successfully predict the purification yield depending on purification conditions with a simple theoretical model. The proposed large-scale purification process could be an important cornerstone for the mass production and industrial use of high-quality QDs. PMID:28240242

  20. Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres

    Science.gov (United States)

    Zhou, Junshuang; Lian, Jie; Hou, Li; Zhang, Junchuan; Gou, Huiyang; Xia, Meirong; Zhao, Yufeng; Strobel, Timothy A.; Tao, Lu; Gao, Faming

    2015-09-01

    Highly porous nanostructures with large surface areas are typically employed for electrical double-layer capacitors to improve gravimetric energy storage capacity; however, high surface area carbon-based electrodes result in poor volumetric capacitance because of the low packing density of porous materials. Here, we demonstrate ultrahigh volumetric capacitance of 521 F cm-3 in aqueous electrolytes for non-porous carbon microsphere electrodes co-doped with fluorine and nitrogen synthesized by low-temperature solvothermal route, rivaling expensive RuO2 or MnO2 pseudo-capacitors. The new electrodes also exhibit excellent cyclic stability without capacitance loss after 10,000 cycles in both acidic and basic electrolytes at a high charge current of 5 A g-1. This work provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance with high mass loadings and charge rates for long-lived electrochemical energy storage systems.

  1. Hybrid microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1985-01-01

    Substrates, particularly inert synthetic organic resin beads (10) or sheet (12) such as polystyrene are coated with a covalently bound layer (24) of polyacrolein by irradiation a solution (14) of acrolein or other aldehyde with high intensity radiation. Individual microspheres (22) are formed which attach to the surface to form the aldehyde containing layer (24). The aldehyde groups can be converted to other functional groups by reaction with materials such as hydroxylamine. Adducts of proteins such as antibodies or enzymes can be formed by direct reaction with the surface aldehyde groups.

  2. Large scale flow visualization and anemometry applied to lab on chip models of porous media

    CERN Document Server

    Paiola, Johan; Bodiguel, Hugues

    2016-01-01

    The following is a report on an experimental technique allowing to quantify and map the velocity field with a very high resolution and a simple equipment in large 2D devices. A simple Shlieren technique is proposed to reinforce the contrast in the images and allow you to detect seeded particles that are pixel-sized or even inferior to it. The velocimetry technique that we have reported on is based on auto-correlation functions of the pixel intensity, which we have shown are directly related to the magnitude of the local average velocity. The characteristic time involved in the decorrelation of the signal is proportional to the tracer size and inversely proportional to the average velocity. We have reported on a detailed discussion about the optimization of relevant involved parameters, the spatial resolution and the accuracy of the method. The technique is then applied to a model porous media made of a random channel network. We show that it is highly efficient to determine the magnitude of the flow in each o...

  3. Analysis of porosity distribution of large-scale porous media and their reconstruction by Langevin equation.

    Science.gov (United States)

    Jafari, G Reza; Sahimi, Muhammad; Rasaei, M Reza; Tabar, M Reza Rahimi

    2011-02-01

    Several methods have been developed in the past for analyzing the porosity and other types of well logs for large-scale porous media, such as oil reservoirs, as well as their permeability distributions. We developed a method for analyzing the porosity logs ϕ(h) (where h is the depth) and similar data that are often nonstationary stochastic series. In this method one first generates a new stationary series based on the original data, and then analyzes the resulting series. It is shown that the series based on the successive increments of the log y(h)=ϕ(h+δh)-ϕ(h) is a stationary and Markov process, characterized by a Markov length scale h(M). The coefficients of the Kramers-Moyal expansion for the conditional probability density function (PDF) P(y,h|y(0),h(0)) are then computed. The resulting PDFs satisfy a Fokker-Planck (FP) equation, which is equivalent to a Langevin equation for y(h) that provides probabilistic predictions for the porosity logs. We also show that the Hurst exponent H of the self-affine distributions, which have been used in the past to describe the porosity logs, is directly linked to the drift and diffusion coefficients that we compute for the FP equation. Also computed are the level-crossing probabilities that provide insight into identifying the high or low values of the porosity beyond the depth interval in which the data have been measured.

  4. Effect of large-scale parameters for two-phase flow in heterogeneous porous media

    Energy Technology Data Exchange (ETDEWEB)

    Girgrah, B.

    1994-01-01

    Important problems in environmental protection and resource management require quantification of parameters at field (large) scale. A numerical model is utilized to construct large-scale capillary pressure (CP) and relative permeability (RP) curves for two-phase flow in heterogeneous porous media. Two-phase flow simulations were performed over a two-dimensional, numerically generated, heterogeneous permeability field. CP and RP curves were constructed for each simulation. The fields ranged in size from 1.25x1.25 m to 5x10 m and had a mean overall log-hydraulic conductivity of [minus]4.6. Flow was vertically downward with the left and right boundaries of the domain remaining impermeable. Following the simulations on heterogeneous fields, homogeneous equivalents were determined and run for sample simulations. The heterogeneous simulations included investigations into the representative elementary volume (REV) for two permeability fields, the effects of fluid properties on CP and RP, and the effects of correlation structure. The equivalent homogeneous simulations explored the feasibility of homogeneous solutions to predict heterogeneous behavior. Results showed that the REVs for fields one and two were a domain size of 50x50 nodes. Fluid property investigations showed that CP decreased when interfacial tension decreased. Structural explorations showed vertical bedding caused an increase in both CP and RP results. A decrease in log-hydraulic conductivity variance caused slight increases in RP and CP. No direct correlation was obtained between homogeneous and heterogeneous flow behavior. A modification could be made to the homogeneous model to allow it to accurately predict heterogeneous flow. 49 refs., 28 figs., 10 tabs.

  5. Nanostructural characterization of large-scale porous alumina fabricated via anodizing in arsenic acid solution

    Science.gov (United States)

    Akiya, Shunta; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2017-05-01

    Anodizing of aluminum in an arsenic acid solution is reported for the fabrication of anodic porous alumina. The highest potential difference (voltage) without oxide burning increased as the temperature and the concentration of the arsenic acid solution decreased, and a high anodizing potential difference of 340 V was achieved. An ordered porous alumina with several tens of cells was formed in 0.1-0.5 M arsenic acid solutions at 310-340 V for 20 h. However, the regularity of the porous alumina was not improved via anodizing for 72 h. No pore sealing behavior of the porous alumina was observed upon immersion in boiling distilled water, and it may be due to the formation of an insoluble complex on the oxide surface. The porous alumina consisted of two different layers: a hexagonal alumina layer that contained arsenic from the electrolyte and a pure alumina honeycomb skeleton. The porous alumina exhibited a white photoluminescence emission at approximately 515 nm under UV irradiation at 254 nm.

  6. Assembly of ordered magnetic microsphere arrays

    Science.gov (United States)

    Xu, Wanling; Ketterson, John

    2008-08-01

    We have developed a straightforward technique to assemble ordered arrays of magnetic microspheres on patterned thin Permalloy (Py) films deposited on the surface of a silicon wafer. Droplets containing micrometer-sized carboxyl paramagnetic microspheres are placed on a horizontally oriented wafer. The field produced by a permanent magnet placed under the wafer is rendered inhomogeneous by the patterned Py features and the resulting field gradients attract and hold the paramagnetic microspheres to these features. While the magnetic microspheres are being attracted to and secured on the pattered Permalloy features, a horizontal flow is created by a pipette, which also removes loose (unsecured) microspheres. By applying this technique to a cocktail of individually functionalized microspheres, a sensor could be realized, which will screen, in parallel, for a large number of targets per unit area. The ability to resolve individual microspheres is close to 100%. A desirable feature is that the substrate is reusable; removing the magnet allows an existing batch of microspheres, which may have lost sensitivity due to environmental exposure, to be flushed from the substrate and replaced with a new batch. The technique complements existing approaches in the field of microarrays widely used in immunoassay, DNA fragment detection, pathogen detection, and other applications in functional genomics and diagnostics.

  7. Optical trapping of coated microspheres.

    Science.gov (United States)

    Bormuth, Volker; Jannasch, Anita; Ander, Marcel; van Kats, Carlos M; van Blaaderen, Alfons; Howard, Jonathon; Schäffer, Erik

    2008-09-01

    In an optical trap, micron-sized dielectric particles are held by a tightly focused laser beam. The optical force on the particle is composed of an attractive gradient force and a destabilizing scattering force. We hypothesized that using anti-reflection-coated microspheres would reduce scattering and lead to stronger trapping. We found that homogeneous silica and polystyrene microspheres had a sharp maximum trap stiffness at a diameter of around 800 nm--the trapping laser wavelength in water--and that a silica coating on a polystyrene microsphere was a substantial improvement for larger diameters. In addition, we noticed that homogeneous spheres of a correct size demonstrated anti-reflective properties. Our results quantitatively agreed with Mie scattering calculations and serve as a proof of principle. We used a DNA stretching experiment to confirm the large linear range in detection and force of the coated microspheres and performed a high-force motor protein assay. These measurements show that the surfaces of the coated microspheres are compatible with biophysical assays.

  8. Aerogel microspheres from natural cellulose nanofibrils and their application as cell culture scaffold.

    Science.gov (United States)

    Cai, Hongli; Sharma, Sudhir; Liu, Wenying; Mu, Wei; Liu, Wei; Zhang, Xiaodan; Deng, Yulin

    2014-07-14

    We demonstrated that ultralight pure natural aerogel microspheres can be fabricated using cellulose nanofibrials (CNF) directly. Experimentally, the CNF aqueous gel droplets, produced by spraying and atomizing through a steel nozzle, were collected into liquid nitrogen for instant freezing followed by freeze-drying. The aerogel microspheres are highly porous with bulk density as low as 0.0018 g cm(-3). The pore size of the cellulose aeogel microspheres ranges from nano- to macrometers. The unique ultralight and high porous structure ensured high moisture (~90 g g(-1)) and water uptake capacity (~100 g g(-1)) of the aerogel microspheres. Covalent cross-linking between the native nanofibrils and cross-linkers made the aerogel microspheres very stable even in a harsh environment. The present study also confirmed this kind of aerogel microspheres from native cellulose fibers can be used as cell culture scaffold.

  9. Operational design and pressure response of large-scale compressed air energy storage in porous formations

    Science.gov (United States)

    Wang, Bo; Bauer, Sebastian

    2017-04-01

    With the rapid growth of energy production from intermittent renewable sources like wind and solar power plants, large-scale energy storage options are required to compensate for fluctuating power generation on different time scales. Compressed air energy storage (CAES) in porous formations is seen as a promising option for balancing short-term diurnal fluctuations. CAES is a power-to-power energy storage, which converts electricity to mechanical energy, i.e. highly pressurized air, and stores it in the subsurface. This study aims at designing the storage setup and quantifying the pressure response of a large-scale CAES operation in a porous sandstone formation, thus assessing the feasibility of this storage option. For this, numerical modelling of a synthetic site and a synthetic operational cycle is applied. A hypothetic CAES scenario using a typical anticline structure in northern Germany was investigated. The top of the storage formation is at 700 m depth and the thickness is 20 m. The porosity and permeability were assumed to have a homogenous distribution with a value of 0.35 and 500 mD, respectively. According to the specifications of the Huntorf CAES power plant, a gas turbine producing 321 MW power with a minimum inlet pressure of 43 bars at an air mass flowrate of 417 kg/s was assumed. Pressure loss in the gas wells was accounted for using an analytical solution, which defines a minimum bottom hole pressure of 47 bars. Two daily extraction cycles of 6 hours each were set to the early morning and the late afternoon in order to bypass the massive solar energy production around noon. A two-year initial filling of the reservoir with air and ten years of daily cyclic operation were numerically simulated using the Eclipse E300 reservoir simulator. The simulation results show that using 12 wells the storage formation with a permeability of 500 mD can support the required 6-hour continuous power output of 321MW, which corresponds an energy output of 3852 MWh per

  10. Fabrication of uranium dioxide ceramic pellets with controlled porosity from oxide microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Dugne, O. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, UMR 5635 CNRS-ENSCM-UM2, University of Montpellier, F-34095 Montpellier cedex 5 (France)

    2014-05-01

    This study concerns the fabrication of uranium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Details are given about oxide microsphere synthesis and particularly about loading operation and heat treatments. The fabrication of ceramic pellets is also described and discussed. Results showed that this process allows the preparation of either dense or porous pellets by mixing U{sub 3}O{sub 8} and UO{sub 2}-like microspheres before pressing and sintering.

  11. Nano pores evolution in hydroxyapatite microsphere during spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Lin C.

    2011-01-01

    Full Text Available Micron-spherical granules of hydroxyapatite (HAp nanoparticles were prepared by powder granulation methods. Through subsequent sintering, porous HAp microspheres with tailored pore and grain framework structures were obtained. Detailed microstructure investigation by SEM and TEM revealed the correlation of the pore structure and the necking strength with the sintering profiles that determine the coalescence features of the nanoparticles. The partially sintered porous HAp microspheres containing more than 50% porosity consisting of pores and grains both in nano-scale are active in inducing the precipitation of HAp in simulated body fluid. The nano-porous HAp microspheres with an extensive surface and interconnecting pores thus demonstrate the potential of stimulating the formation of collagen and bone and the integration with the newly formed bones during physiological bone remodeling.

  12. Glass microspheres for medical applications

    Science.gov (United States)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in 100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass

  13. Preparation and structure of drug-carrying biodegradable microspheres designed for transarterial chemoembolization therapy.

    Science.gov (United States)

    Wang, Yujing; Benzina, Abderazak; Molin, Daniel G M; Akker, Nynke van den; Gagliardi, Mick; Koole, Leo H

    2015-01-01

    Biodegradable poly(D,L-lactic acid) drug-eluting microspheres containing anti-tumor drugs, cisplatin, and sorafenib tosylate have been prepared by the emulsion solvent evaporation method with diameter between 200 and 400 μm. Scanning electron microscopy showed that cisplatin microspheres had smooth surfaces, while sorafenib tosylate microspheres and cisplatin + sorafenib tosylate microspheres were porous at the surface and the pits of the latter were larger than those of the former. Notably, cisplatin + sorafenib tosylate microspheres had a fast drug release rate compared with microspheres containing one drug alone. In vitro cytotoxicity experiments and classical matrigel endothelial tube assay certificated the maintaining bioactivity of cisplatin and sorafenib tosylate released from the microspheres, respectively. This work provides a useful approach for the fabrication of drug-eluting beads used in transarterial chemoembolization.

  14. Liquid film condensation along a vertical surface in a thin porous medium with large anisotropic permeability.

    Science.gov (United States)

    Sanya, Arthur S O; Akowanou, Christian; Sanya, Emile A; Degan, Gerard

    2014-01-01

    The problems of steady film condensation on a vertical surface embedded in a thin porous medium with anisotropic permeability filled with pure saturated vapour are studied analytically by using the Brinkman-Darcy flow model. The principal axes of anisotropic permeability are oriented in a direction that non-coincident with the gravity force. On the basis of the flow permeability tensor due to the anisotropic properties and the Brinkman-Darcy flow model adopted by considering negligible macroscopic and microscopic inertial terms, boundary-layer approximations in the porous liquid film momentum equation is solved analytically. Scale analysis is applied to predict the order-of-magnitudes involved in the boundary layer regime. The first novel contribution in the mathematics consists in the use of the anisotropic permeability tensor inside the expression of the mathematical formulation of the film condensation problem along a vertical surface embedded in a porous medium. The present analytical study reveals that the anisotropic permeability properties have a strong influence on the liquid film thickness, condensate mass flow rate and surface heat transfer rate. The comparison between thin and thick porous media is also presented.

  15. Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Shaofang; Zhu, Chengzhou; Song, Junhua; Engelhard, Mark H.; Xia, Haibing; Du, Dan; Lin, Yuehe

    2016-12-28

    Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetic reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the resultant PtCu hierarchically porous nanostructures with optimized composition exhibit enhanced electrocatalytic performance for oxygen reduction reaction.

  16. Liquid film condensation along a vertical surface in a thin porous medium with large anisotropic permeability

    OpenAIRE

    Sanya, Arthur S O; Akowanou, Christian; Sanya, Emile A; Degan, Gerard

    2014-01-01

    The problems of steady film condensation on a vertical surface embedded in a thin porous medium with anisotropic permeability filled with pure saturated vapour are studied analytically by using the Brinkman-Darcy flow model. The principal axes of anisotropic permeability are oriented in a direction that non-coincident with the gravity force. On the basis of the flow permeability tensor due to the anisotropic properties and the Brinkman-Darcy flow model adopted by considering negligible macros...

  17. Large deformation ionic polymer-metal composites actuators based on porous Nafion membranes

    Science.gov (United States)

    Zhao, Dongxu; Li, Dichen; Wang, Yanjie; Luo, Meng; Chen, Hualing

    2016-04-01

    With advantages of low driving voltage, good flexibility and high electromechanical efficiency, ionic polymer-metal composites (IPMCs), which are one of the most attractive smart materials, have been research hotspot in actuators, sensors and artificial muscles. However, a serious drawback of little deformation of thick IPMC actuator limits its application. In this paper, we fabricated thick porous Nafion membranes by freeze-drying process. A series of Thermogravimetric analyses (TGA), Field emission scanning electron microscopy (FE-SEM) and Water uptake (WUP) tests were performed to examine the validity of the freeze-drying process and the pore size and the porosity. Then, the porous IPMCs were fabricated with the freeze-drying processed Nafion membranes by the solution casting and reducing plating. Finally, the IPMC actuators with the dimensions of 25× 5× 1 in millimeters were achieved and tested. The terminal deformation of the porous IPMC actuator increased by 739.7%, compared with the ordinary IPMC actuator with the same dimensions under the driving voltage of 2VDC.

  18. Monodisperse REPO4 (RE = Yb, Gd, Y) hollow microspheres covered with nanothorns as affinity probes for selectively capturing and labeling phosphopeptides.

    Science.gov (United States)

    Cheng, Gong; Zhang, Ji-Lin; Liu, Yan-Lin; Sun, De-Hui; Ni, Jia-Zuan

    2012-02-13

    Rare-earth phosphate microspheres with unique structures were developed as affinity probes for the selective capture and tagging of phosphopeptides. Prickly REPO(4) (RE = Yb, Gd, Y) monodisperse microspheres, that have hollow structures, low densities, high specific surface areas, and large adsorptive capacities were prepared by an ion-exchange method. The elemental compositions and crystal structures of these affinity probes were confirmed by energy-dispersive spectroscopy (EDS), powder X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The morphologies of these compounds were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen-adsorption isotherms. The potential ability of these microspheres for selectively capturing and labeling target biological molecules was evaluated by using protein-digestion analysis and a real sample as well as by comparison with the widely used TiO(2) affinity microspheres. These results show that these porous rare-earth phosphate microspheres are highly promising probes for the rapid purification and recognition of phosphopeptides.

  19. Convenient and large-scale synthesis of nitrogen-rich hierarchical porous carbon spheres for supercapacitors and CO2 capture

    Science.gov (United States)

    Chang, Binbin; Zhang, Shouren; Yin, Hang; Yang, Baocheng

    2017-08-01

    Herein, considering the great potential of nitrogen-doped hierarchical porous carbons in energy storage and CO2 capture, we designed a convenient and easily large-scale production strategy for preparing nitrogen-doped hierarchical porous carbon sphere (NHPCS) materials. In this synthesis route, spherical resorcinol-formaldehyde (RF) resins were selected as carbon precursor, and then the ZnCl2-impregnated RF resin spheres were carbonized in a NH3 atmosphere at a temperature range of 600-800 °C. During the one-step heat-treatment process, nitrogen atom could be efficiently incorporated into the carbon skeleton, and the interconnected and hierarchical pore structure with different micro/mesopore proportion could be generated and tuned by adjusting the activating agent ZnCl2 dosage and carbonization temperature. The resultant nitrogen-doped hierarchical porous carbon sphere materials exhibited a satisfactory charge storage capacity, and the optimal sample of NHPCS-2-8 with a high mesopore proportion obtained at 800 °C with a ZnCl2/RF mass ratio of 2:1 presented a specific capacitance of 273.8 F g-1 at a current density of 0.5 A g-1. More importantly, the assembled NHPCS-2-8-based symmetric capacitor displayed a high energy density of 17.2 Wh kg-1 at a power density of 178.9 W kg-1 within a voltage window of 0 ∼ 1.8 V in 0.5 M Na2SO4 aqueous electrolyte. In addition, the CO2 capture application of these NHPCS materials was also explored, and the optimal sample of NHPCS-0-8 with a large micropore proportion prepared at 800 °C exhibited an exceptional CO2 uptake capacity at ambient pressures of up to 4.23 mmol g-1 at 0 °C.

  20. [Transcatheter Arterial Chemoembolization with Super absorbent Polymer Microspheres for a Large Lung Cystic Adenocarcinoma in the Left Pulmonary Cavity].

    Science.gov (United States)

    Kennoki, Norifumi; Hori, Shinichi; Yuki, Takeo; Sueyoshi, Satoshi; Hori, Atsushi

    2015-11-01

    A 57-year-old woman presented with lung adenocarcinoma and carcinomatous pleurisy in January 2013. The primary lesion had been treated with 60-Gy radiation therapy. She, however, showed a recurrence of the tumor in her pulmonary cavity. She received systemic chemotherapy for 1 year but did not show any improvement. She visited our clinic in March 2014. Her performance level was 3. Her hemoglobin level was 8.5 g/dL. The CT scan showed that the size of the cystic tumor was 200 × 144 × 143 mm. The tumor severely compressed her heart. We performed TACE using a spherical embolic agent. The microcatheter was guided through the left bronchial artery; left intercostal artery 9, 10, and 11; and the left inferior phrenic artery. The anticancer drugs selected were CDDP and 5-FU. The embolic material used was SAP-MS. After 3 therapy sessions, the CT scan showed shrinkage of the target lesion to 100 × 93 × 54 mm. Her hemoglobin level increased to 13.8 g/dL; furthermore, the severity of dyspnea decreased, and she showed a performance status of 0. TACE with SAP-MS was successfully performed for the large cystic tumor in the pulmonary cavity that metastasized from the lung cancer and was refractory to standard treatments. After the treatment, the tumor size decreased and the patient's symptoms alleviated.

  1. 界面溶蚀法制备多孔磺化聚苯乙烯/壳聚糖微球及其Cr3+吸附研究%Preparation of porous sulphonated polystyrene/chitosan microspheres via solvent/nonsolvent induced phase separation and its application on adsorption Cr3+

    Institute of Scientific and Technical Information of China (English)

    李鑫; 宋林勇; 周艺峰; 聂王焰; 陈鹏鹏

    2014-01-01

    Sulfonated Polystyrene( SPS)microsPheres were used as temPlates and core-shell SPS/CS mi-crosPheres were PrePared by adsorbing chitosan onto the SPS surface via electrostatic interaction between amino and sulfoacid grouPs. Porous structured SPS and SPS/CS microsPheres were PrePared by solvent/nonsolvent induced Phase seParation method. Transmission electron microscoPy( TEM)was used to ob-serve the microstructure and the Cr3+ adsorPtion behavior was characterized by UV-Vis at room temPera-ture. The results indicated that the uniform morPhology of the Porous Polymer microsPheres was PrePared by interface dissolution method. And the Porous SPS/CS showed an obviously enhanced maximum adsorP-tive caPacity to Cr3+.%采用固/液界面溶剂溶胀诱导相分离法,对磺化聚苯乙烯( SPS)和表面负载有生物相容性的壳聚糖( CS)的核壳型SPS/CS两种微球进行溶蚀,制备出具有多孔结构的SPS和SPS/CS微球。研究发现,溶剂类型和醇水比是影响多孔聚合物微球形态的主要因素。利用透射电镜( TEM)对多孔微球的结构进行表征,通过紫外可见分光光度计( UV-Vis)测定SPS/CS多孔微球在室温环境下对Cr3+的吸附行为。结果表明,界面溶蚀法可制备出形貌均一的多孔聚合物微球,其对Cr3+吸附量明显优于实心结构的微球。

  2. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  3. Large-scale preparation of strawberry-like, AgNP-doped SiO2 microspheres using the electrospraying method

    Science.gov (United States)

    Ma, Zhijun; Ji, Huijiao; Tan, Dezhi; Dong, Guoping; Teng, Yu; Zhou, Jiajia; Guan, Miaojia; Qiu, Jianrong; Zhang, Ming

    2011-07-01

    In this paper, we report on a novel strategy for the preparation of silver nanoparticle-doped SiO2 microspheres (Ag-SMSs) with an interesting strawberry-like morphology using a simple and efficient electrospraying method. SEM (scanning electron microscopy), TEM (transmission electron microscopy), XRD (x-ray diffraction), EDS (energy-dispersive spectroscopy) and UV-vis spectra (ultraviolet-visible spectra) were applied to investigate the morphology, structure, composition and optical properties of the hybrid microspheres, and E. coli (Escherichia coli) was used as a model microbe to evaluate their antibacterial ability. The results showed that the Ag-SMSs were environmentally stable and washing resistant. The Ag-SMSs exhibited effective inhibition against proliferation of E. coli, and their antibacterial ability could be well preserved for a long time. The environmental stability, washing resistance, efficient antibacterial ability and simple but productive preparation method endowed the Ag-SMSs with great potential for practical biomedical applications.

  4. Porous silicon Bloch surface and sub-surface wave structure for simultaneous detection of small and large molecules

    Science.gov (United States)

    Rodriguez, Gilberto A.; Lonai, John D.; Mernaugh, Raymond L.; Weiss, Sharon M.

    2014-08-01

    A porous silicon (PSi) Bloch surface wave (BSW) and Bloch sub-surface wave (BSSW) composite biosensor is designed and used for the size-selective detection of both small and large molecules. The BSW/BSSW structure consists of a periodic stack of high and low refractive index PSi layers and a reduced optical thickness surface layer that gives rise to a BSW with an evanescent tail that extends above the surface to enable the detection of large surface-bound molecules. Small molecules were detected in the sensor by the BSSW, which is a large electric field intensity spatially localized to a desired region of the Bragg mirror and is generated by the implementation of a step or gradient refractive index profile within the Bragg mirror. The step and gradient BSW/BSSW sensors are designed to maximize both resonance reflectance intensity and sensitivity to large molecules. Size-selective detection of large molecules including latex nanospheres and the M13KO7 bacteriophage as well as small chemical linker molecules is reported.

  5. Making Polymeric Microspheres

    Science.gov (United States)

    Rhim, Won-Kyu; Hyson, Michael T.; Chung, Sang-Kun; Colvin, Michael S.; Chang, Manchium

    1989-01-01

    Combination of advanced techniques yields uniform particles for biomedical applications. Process combines ink-jet and irradiation/freeze-polymerization techniques to make polymeric microspheres of uniform size in diameters from 100 to 400 micrometer. Microspheres used in chromatography, cell sorting, cell labeling, and manufacture of pharmaceutical materials.

  6. Expanded porous MOF-505 analogue exhibiting large hydrogen storage capacity and selective carbon dioxide adsorption.

    Science.gov (United States)

    Zheng, Baishu; Yun, Ruirui; Bai, Junfeng; Lu, Zhiyong; Du, Liting; Li, Yizhi

    2013-03-18

    An expanded 4,4-paddlewheel-connected porous MOF-505-type metal-organic framework (MOF), [Cu2(PDEB)(H2O)2]·xS (NJU-Bai12; NJU-Bai represents the Nanjing University Bai group and S represents noncoordinated solvent molecules) has been designed from a nanosized rectangular diisophthalate linker containing alkyne groups 5,5'-(1,4-phenylenedi-2,1-ethynediyl)bis(1,3-benzenecarboxylic acid). This MOF material possesses permanent microporosity with the highest Brunauer-Emmett-Teller surface area of 3038 m(2)·g(-1) and the largest unsaturated total hydrogen storage capacity of 62.7 mg·g(-1) at 77 K and 20 bar among reported MOF-505 analogues. Additionally, NJU-Bai12 also exhibits excellent carbon dioxide (CO2) uptake capacity (23.83 and 19.85 mmol·g(-1) at 20 bar for 273 and 298 K, respectively) and selective gas adsorption properties with CO2/CH4 selectivity of 5.0 and CO2/N2 selectivity of 24.6 at room temperature.

  7. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, Richard W. (Pleasant Hill, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  8. Compression molding of aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  9. Boundary layer development over a large array of porous-disk-modeled wind turbines via stereo particle image velocimetry

    Science.gov (United States)

    Camp, Elizabeth; Vuppuluri, Vasant; Cal, Raúl

    2014-11-01

    The increasing size of wind turbine arrays in service highlights the importance of understanding the flow physics within such large turbine arrays. Thus, the development of a wind turbine array boundary layer (WTBL) was investigated experimentally for an 8 × 5 array of model wind turbines. Model wind turbines were on a 1:2000 scale and turbine rotors were represented by porous disks. Stereoscopic Particle Image Velocimetry (SPIV) measurements were done along the centerline of the wind turbine array at several streamwise positions both within and above the canopy. Measurements and analysis of the mean and streamwise-averaged statistics of the SPIV fields focus on the rotors in the furthest downstream positions. Statistics will be used to determine if a fully developed WTBL has been achieved.

  10. Fabrication of chitin microspheres and their multipurpose application as catalyst support and adsorbent.

    Science.gov (United States)

    Wang, Yuntao; Li, Yan; Liu, Shilin; Li, Bin

    2015-04-20

    In this study, novel chitin microspheres (CM) with diameters of 1010 μm, 750 μm, 490 μm, 280 μm were fabricated by employing the sol-gel transition method. Then the chitin microspheres served as the enabling platform for a range of applications including recyclable catalyst support and adsorbent. First, the freeze dried porous chitin microspheres were coated with dopamine to enhance the loading efficiency of a model biomacromolecule, α-amylase. The immobilized enzyme (49.6 mg/g) retained more than 95% of relative activity after 10 repeated cycles and exhibited easy recovery ability. Then porous magnetic chitin microspheres could be prepared, and the swollen porous polymer successfully controlled the growth of gold nanoparticles. The chitin/Au nanocomposite microspheres were a good recyclable catalyst due to the porous structure and a reduced dimension of the metal particles (r ≤ 5 nm). Finally, the magnetic chitin microspheres were modified into an adsorbent for enhanced removal of a typical cationic compound, methylene blue from aqueous solution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. High Resolutions Obtained by Microspheres, and Phase Contrast Microscope with a Microsphere

    CERN Document Server

    Ben-Aryeh, Y

    2015-01-01

    High resolutions obtained in optical systems with microspheres are studied by Helmholtz equation and boundary conditions for the EM fields. The large lateral spatial wave vectors of the evanescent waves, which include information on the fine structures of the object, are converted at the microsphere surface to smaller spatial wave vectors. Due to reduction in the magnitudes of these spatial wave vectors a part of the EM waves propagate in the microsphere without decay, but preserve the fine structures which can be recovered in the image plane. A new method for measuring phase objects, like those of semi-transparent biological tissues, with high resolutions is described by an optical system composed of a combination of the microsphere with an interferometer.

  12. Surface wrinkling on polydimethylsiloxane microspheres via wet surface chemical oxidation.

    Science.gov (United States)

    Yin, Jian; Han, Xue; Cao, Yanping; Lu, Conghua

    2014-07-16

    Here we introduce a simple low-cost yet robust method to realize spontaneously wrinkled morphologies on spherical surfaces. It is based on surface chemical oxidation of aqueous-phase-synthesized polydimethylsiloxane (PDMS) microspheres in the mixed H2SO4/HNO3/H2O solution. Consequently, curvature and overstress-sensitive wrinkles including dimples and labyrinth patterns are successfully induced on the resulting oxidized PDMS microspheres. A power-law dependence of the wrinkling wavelength on the microsphere radius exists. The effects of experimental parameters on these tunable spherical wrinkles have been systematically investigated, when the microspheres are pre-deposited on a substrate. These parameters include the radius and modulus of microspheres, the mixed acid solution composition, the oxidation duration, and the water washing post-treatment. Meanwhile, the complicated chemical oxidation process has also been well studied by in-situ optical observation via the microsphere system, which represents an intractable issue in a planar system. Furthermore, we realize surface wrinkled topographies on the whole microspheres at a large scale, when microspheres are directly dispersed in the mixed acid solution for surface oxidation. These results indicate that the introduced wet surface chemical oxidation has the great potential to apply to other complicated curved surfaces for large-scale generation of well-defined wrinkling patterns, which endow the solids with desired physical properties.

  13. Microsphere Insulation Panels

    Science.gov (United States)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  14. Composition and structure of calcium aluminosilicate microspheres

    Science.gov (United States)

    Sharonova, O. M.; Oreshkina, N. A.; Zhizhaev, A. M.

    2017-06-01

    The composition was studied of calcium aluminosilicate microspheres of three morphological types in high-calcium fly ash from combustion of brown coal from the Kansk-Achinsk basin in slag-tap boilers at temperatures from 1400 to 1500°C and sampled in the first field of electrostatic precipitators at the Krasnoyarsk Cogeneration Power Station no. 2 (TETs-2). Gross compositions and the composition of local areas were determined using a scanning electron microscopy technique and an energy-dispersive analysis with full mapping of globules. With a high content of basic oxides O ox (68 to 79 wt %) and a low content of acid oxides K ox (21 to 31 wt %), type 1 microspheres are formed. They consist of heterogeneous areas having a porous structure and crystalline components in which the content of CaO, SiO2, or Al2O3 differs by two to three times and the content of MgO differs by seven times. With a lower content of O ox (55 to 63 wt %) and an elevated content of K ox (37 to 45 wt %), type 2 microspheres are formed. They are more homogeneous in the composition and structure and consist of similar crystalline components. Having a close content of O ox (46 to 53 wt %) and K ox (47 to 54 wt %), type 3 microspheres, which are a dense matter consisting of amorphous substance with submicron- and nanostructure of crystalline components, are formed. The basic precursor in formation of high-calcium aluminosilicate microspheres is calcium from the organomineral matter of coals with various contribution of Mg, Fe, S, or Na from the coal organic matter and Al, Fe, S, or Si in the form of single mineral inclusions in a coal particle. On the basis of the available data, the effect was analyzed of the composition of a CaO-MgO-Al2O3-SiO2-FeO system on the melting and viscous properties of the matter in microspheres and formation of globules of different morphology. The results of this analysis will help to find a correlation with properties of microspheres in their use as functional

  15. Rapid microwave-assisted green synthesis of 3D hierarchical flower-shaped NiCo₂O₄ microsphere for high-performance supercapacitor.

    Science.gov (United States)

    Lei, Ying; Li, Jing; Wang, Yanyan; Gu, Li; Chang, Yuefan; Yuan, Hongyan; Xiao, Dan

    2014-02-12

    Binary metal oxides with three-dimensional (3D) superstructure have been regarded as desirable electrode materials for the supercapacitor due to the combination of the improved electrical conductivity and effective porous structure. 3D hierarchical flower-shaped nickel cobaltite (NiCo2O4) microspheres have been fabricated by a rapid and template-free microwave-assisted heating (MAH) reflux approach followed by pyrolysis of the as-prepared precursors. The flower-shaped NiCo2O4 microspheres, composed of ultrathin nanopetals with thickness of about 15 nm, are endowed with large specific surface area (148.5 m(2) g(-1)) and a narrow pore size distribution (5-10 nm). The as-fabricated porous flower-shaped NiCo2O4 microspheres as electrode materials for supercapacitor exhibited high specific capacitance of 1006 F g(-1) at 1 A g(-1), enhanced rate capability, and excellent electrochemical stability with 93.2% retention after 1000 continuous charge-discharge (CD) cycles even at a high current density of 8 A g(-1). The desirable integrated performance enables it to be a promising electrode material for the electrochemical supercapacitor (EC).

  16. In vitro and in vivo evaluation of drug-eluting microspheres designed for transarterial chemoembolization therapy.

    Science.gov (United States)

    Wang, Yujing; Molin, Daniël G M; Sevrin, Chantal; Grandfils, Christian; van den Akker, Nynke M S; Gagliardi, Mick; Knetsch, Menno L; Delhaas, Tammo; Koole, Leo H

    2016-04-30

    Poly(D,L-lactic acid) biodegradable microspheres, loaded with the drugs cisplatin and/or sorafenib tosylate, were prepared, characterized and studied. Degradation of the microspheres, and release of cisplatin and/or sorafenib tosylate from them, were investigated in detail. Incubation of the drug-carrying microspheres in phosphate buffered saline (pH=7.4) revealed slow degradation. Nevertheless, significant release of cisplatin and sorafenib tosylate from microspheres loaded with both drugs was apparent in vitro; this can be attributed to their porous structure. Supernatants from microspheres loaded with both drugs showed strong toxic effects on cells (i.e. endothelial cells, fibroblast cells and Renca tumor cells) and potent anti-angiogenic effect in the matrigel endothelial tube assay. In vivo anti-tumor effects of the microspheres were also observed, in a Renca tumor mouse model. The poly(D,L-lactic acid) microspheres containing both cisplatin and sorafenib tosylate revealed highest therapeutic efficacy, probably demonstrating that combined local administration of cisplatin and sorafenib tosylate synergistically inhibits tumor growth in situ. In conclusion, this study demonstrates the applicability of biodegradable poly(D,L-lactic acid) microspheres loaded with cisplatin and sorafenib tosylate for local drug delivery as well as the potential of these microspheres for future use in transarterial chemoembolization.

  17. Preparation, characterization, and in vitro release of gentamicin from coralline hydroxyapatite-alginate composite microspheres.

    Science.gov (United States)

    Sivakumar, M; Rao, K Panduranga

    2003-05-01

    In this work, composite microspheres were prepared from bioactive ceramics such as coralline hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] granules, a biodegradable polymer, sodium alginate, and an antibiotic, gentamicin. Previously, we have shown a gentamicin release from coralline hydroxyapatite granules-chitosan composite microspheres. In the present investigation, we attempted to prepare composite microspheres containing coralline hydroxyapatite granules and sodium alginate by the dispersion polymerization technique with gentamicin incorporated by absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. Fourier transform infrared spectra clearly indicated the presence of per-acid of sodium alginate, phosphate, and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs showed that the composite microspheres were spherical in shape and porous in nature. The particle size of composite microspheres was analyzed, and the average size was found to be 15 microns. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns.

  18. Novel Erythrocyte-like Graphene Microspheres with High Quality and Mass Production Capability via Electrospray Assisted Self-Assembly

    Science.gov (United States)

    Tian, Yayang; Wu, Guan; Tian, Xike; Tao, Xiaoming; Chen, Wei

    2013-11-01

    We report for the first time a novel erythrocyte-like graphene microsphere (ELGMs) which can be produced with high quality and mass production capability via electrospray assisted self-assembly. Through simple electrospray treatment of GO suspension into coagulation bath followed by chemical reduction, large quantity of ELGMs with uniform morphology and size can be obtained with production rate of around 2.4 mg/h. Compared with other 3D structures, the ELGMs have a very interesting structural characteristic of perfect exterior doughnut shape and interior porous network. Accordingly, the as-prepared porous ELGMs exhibit excellent capability for fast and recyclable removal of oil and toxic organic solvents from water, reaching up to 216 times of its weight in absorption efficiency, which is tens of times higher than that of conventional sorbent materials. It is strongly believed that the novel hierarchical graphene structures and synergy among different techniques will lead to more future advances in graphene applications.

  19. Repair of large osteochondral defects in rabbits using porous hydroxyapatite/collagen (HAp/Col) and fibroblast growth factor-2 (FGF-2).

    Science.gov (United States)

    Maehara, Hidetsugu; Sotome, Shinichi; Yoshii, Toshitaka; Torigoe, Ichiro; Kawasaki, Yuichi; Sugata, Yumi; Yuasa, Masato; Hirano, Masahiro; Mochizuki, Naomi; Kikuchi, Masanori; Shinomiya, Kenichi; Okawa, Atsushi

    2010-05-01

    Articular cartilage has a limited capacity for self-renewal. This article reports the development of a porous hydroxyapatite/collagen (HAp/Col) scaffold as a bone void filler and a vehicle for drug administration. The scaffold consists of HAp nanocrystals and type I atelocollagen. The purpose of this study was to investigate the efficacy of porous HAp/Col impregnated with FGF-2 to repair large osteochondral defects in a rabbit model. Ninety-six cylindrical osteochondral defects 5 mm in diameter and 5 mm in depth were created in the femoral trochlear groove of the right knee. Animals were assigned to one of four treatment groups: porous HAp/Col impregnated with 50 microl of FGF-2 at a concentration of 10 or 100 microg/ml (FGF10 or FGF100 group); porous HAp/Col with 50 microl of PBS (HAp/Col group); and no implantation (defect group). The defect areas were examined grossly and histologically. Subchondral bone regeneration was quantified 3, 6, 12, and 24 weeks after surgery. Abundant bone formation was observed in the HAp/Col implanted groups as compared to the defect group. The FGF10 group displayed not only the most abundant bone regeneration but also the most satisfactory cartilage regeneration, with cartilage presenting a hyaline-like appearance. These findings suggest that porous HAp/Col with FGF-2 augments the cartilage repair process.

  20. Organic aerogel microspheres

    Science.gov (United States)

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  1. Organic aerogel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  2. MAGNETIC MICROSPHERES: A LATEST APPROACH IN NOVEL DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Mukherjee S

    2012-10-01

    Full Text Available Magnetic microspheres are at the forefront of the rapidly developing field of pharmaceutical technology with several potential applications in drug delivery, clinical medicine and research as well as in other varied sciences. Due to their unique size-dependent properties, magnetic microspheres offer the possibility to develop new therapeutics. The ability to incorporate drugs into carriers offers a new prototype in drug delivery that could be used for secondary and tertiary levels of drug targeting. Hence, magnetic microspheres hold great promise for reaching the goal of controlled and site specific drug delivery and hence have attracted wide attention of researchers. This review presents a broad treatment of magnetic microspheres discussing their advantages, limitations and their possible remedies. Different production methods which are suitable for large scale production and applications of magnetic microspheres are described. Appropriate analytical techniques for characterization of magnetic microspheres like Photon correlation spectroscopy, scanning electron microscopy, differential scanning calorimetry are highlighted. Aspects of magnetic microspheres route of administration and their biodistribution are also incorporated. If appropriately investigated, magnetic microspheres may open new vistas in therapy of complex diseases.

  3. Hollow carbonated hydroxyapatite microspheres with mesoporous structure: hydrothermal fabrication and drug delivery property.

    Science.gov (United States)

    Guo, Ya-Jun; Wang, Ying-Ying; Chen, Ting; Wei, Yi-Ting; Chu, Lian-Feng; Guo, Ya-Ping

    2013-08-01

    Hollow carbonated hydroxyapatite microspheres with mesoporous structure (HCHAs) have been fabricated by using calcium carbonated microspheres as sacrificial templates according to the following routes: (i) the in situ deposit of carbonated hydroxyapatite on the surfaces of CaCO3 microspheres by hydrothermal method and (ii) the removal of CaCO3 by chemical etching. The HCHAs consist of a hollow core and a mesoporous shell. Interestingly, the shell of the microspheres is constructed by carbonated hydroxyapatite nanoplates as building blocks. Moreover, these nanoplates are composed of many smaller nanoparticles with different crystal orientations, and the mesopores exist among these nanoparticles. The HCHAs exhibit the high drug-loading capacity and sustained drug release property, suggesting that the hierarchically porous microspheres have great potentials for bone-implantable drug-delivery applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Quantum Magnetomechanics with Levitating Superconducting Microspheres

    CERN Document Server

    Romero-Isart, O; Navau, C; Sanchez, A; Cirac, J I

    2011-01-01

    We show that by magnetically trapping a superconducting microsphere close to a quantum circuit, it is experimentally feasible to perform ground state cooling and to prepare quantum superpositions of the center-of-mass motion of the microsphere. Due to the absence of clamping losses and time dependent electromagnetic fields, the mechanical motion of micrometer-sized metallic spheres in the Meissner state is predicted to be extremely well isolated from the environment. Hence, we propose to combine the technology of magnetic mictrotraps and superconducting qubits to bring relatively large objects to the quantum regime.

  5. The research progress of polyimide microspheres%聚酰亚胺微球的研究进展

    Institute of Scientific and Technical Information of China (English)

    方雪; 苏桂明; 马宇良; 陈明月; 张晓臣

    2015-01-01

    聚酰亚胺微球是一类具有耐高温、耐溶剂性以及较低的介电性能的高比表面积的高分子材料,具有广阔的应用前景。通过探讨几类聚酰亚胺实心微球、中空微球、多孔微球以及复合微球的研究,发现这些方法仍然存在各种不同的缺点和问题。%Polyimide microspheres were considered as a class of polymer materials with high temperature resistance, solvent resistance and low dielectric properties and high specific surface area. In this article, the research progress of various polyimide microspheres including solid microspheres, hollow microspheres, porous microspheres and composite microspheres were reviewed.

  6. Large scale flow visualization and anemometry applied to lab-on-a-chip models of porous media.

    Science.gov (United States)

    Paiola, Johan; Auradou, Harold; Bodiguel, Hugues

    2016-08-01

    The following is a report on an experimental technique that allows one to quantify and map the velocity field with very high resolution and simple equipment in large 2D devices. Illumination through a grid is proposed to reinforce the contrast in the images and allow one to detect seeded particles that are pixel-sized or even smaller. The velocimetry technique that we have reported is based on the auto-correlation functions of the pixel intensity, which we have shown are directly related to the magnitude of the local average velocity. The characteristic time involved in the decorrelation of the signal is proportional to the tracer size and inversely proportional to the average velocity. We have reported on a detailed discussion about the optimization of relevant involved parameters, the spatial resolution and the accuracy of the method. The technique is then applied to a model porous medium made of a random channel network. We show that it is highly efficient to determine the magnitude of the flow in each of the channels of the network, opening the door to the fundamental study of the flows of complex fluids. The latter is illustrated with a yield stress fluid, in which the flow becomes highly heterogeneous at small flow rates.

  7. Hierarchically-Porous Carbon Derived from a Large-Scale Iron-based Organometallic Complex for Versatile Energy Storage.

    Science.gov (United States)

    Fan, Chao-Ying; Li, Huan-Huan; Wang, Hai-Feng; Sun, Hai-Zhu; Wu, Xing-Long; Zhang, Jing-Ping

    2016-06-22

    Inspired by the preparation of the hierarchically-porous carbon (HPC) derived from metal organic frameworks (MOFs) for energy storage, in this work, a simple iron-based metal- organic complex (MOC), which was simpler and cheaper compared with the MOF, was selected to achieve versatile energy storage. The intertwined 1 D nanospindles and enriched-oxygen doping of the HPC was obtained after one-step carbonization of the MOC. When employed in lithium-ion batteries, the HPC exhibited reversible capacity of 778 mA h g(-1) after 60 cycles at 50 mA g(-1) . Moreover, the HPC maintained a capacity of 188 mA h g(-1) after 400 cycles at 100 mA g(-1) as the anode material in a sodium-ion battery. In addition, the HPC served as the cathode matrix for evaluation of a lithium-sulfur battery. The general preparation process of the HPC is commercial, which is responsible for the large-scale production for its practical application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent.

    Science.gov (United States)

    Zhang, Huanyu; Yong, Xueyong; Zhou, Jinyong; Deng, Jianping; Wu, Youping

    2016-02-03

    The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes.

  9. Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery.

    Science.gov (United States)

    Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

    2014-01-01

    A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery.

  10. Bovine serum albumin adsorption to iron-oxide coated sands can change microsphere deposition mechanisms.

    Science.gov (United States)

    Flynn, Raymond M; Yang, Xinyao; Hofmann, Thilo; von der Kammer, Frank

    2012-03-06

    Particulate colloids often occur together with proteins in sewage-impacted water. Using Bovine Serum Albumin (BSA) as a surrogate for protein in sewage, column experiments investigating the capacity of iron-oxide coated sands to remove latex microspheres from water revealed that microsphere attenuation mechanisms depended on antecedent BSA coverage. Dual pulse experiment (DPE) results suggested that where all BSA was adsorbed, subsequent multiple pore volume microsphere breakthrough curves reflected progressively reduced colloid deposition rates with increasing adsorbed BSA content. Modeling colloid responses suggested adsorption of 1 μg BSA generated the same response as blockage by between 7.1 × 10(8) and 2.3 × 10(9) deposited microspheres. By contrast, microsphere responses in DPEs where BSA coverage of the deposition sites approached/reached saturation revealed the coated sand maintained a finite capacity to attenuate microspheres, even when incapable of further BSA adsorption. Subsequent microsphere breakthrough curves demonstrated the matrix's colloid attenuation capacity progressively increased with continued microsphere deposition. Experimental findings suggested BSA adsorption on the sand surface approaching/reaching saturation generated attractive deposition sites for colloids, which became progressively more attractive with further colloid deposition (filter ripening). Results demonstrate that adsorption of a single type of protein may either enhance or inhibit colloid mobility in saturated porous media.

  11. Formulation and evaluation of Zidovudine loaded chitosan Microspheres for controlled release

    Directory of Open Access Journals (Sweden)

    Kesari Asha

    2012-03-01

    Full Text Available The aim of this study was to formulate and evaluate zidovudine loaded chitosan microspheres for controlled drug release. Microspheres were prepared by emulsification method using gluteraldehyde as crosslinking agent. The prepared microspheres were characterized for their yield and drug loading, as well by Fourier transform infrared spectroscopy (FTIR, X-ray powder diffractometry and Scanning electron microscopy. The in vitro release studies were performed in pH 7.4, phosphate buffer. The prepared microspheres were free flowing and spherical in shape. The drugloaded microspheres showed 72-94% of entrapment and release was extended up to 12h. The infrared spectra showed stable character of zidovudine in the drugloaded microspheres and revealed the absence of drugpolymer interactions. X-ray diffraction patterns showed that there was decrease in crystallinity of the drug. Scanning electron microscopy study revealed that the microspheres were spherical and porous in nature. It was found that the drug: polymer ratio, the stirring speed, the concentration of surfactant, and the amount of gluteraldehyde used for crosslinking were the most significant variables which influenced the size of the chitosan microspheres under the applied experimental condition.

  12. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  13. Doppler cooling a microsphere

    CERN Document Server

    Barker, P F

    2010-01-01

    Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity dependent scattering force from narrow whispering gallery mode (WGM) resonances is described. Light that is red detuned from the WGM resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. Leakage of photons out of the microsphere when the incident field is near resonant with the narrow WGM resonance acts to damp the motion of the sphere. The scattering force is not limited by saturation, but can be controlled by the incident power. Cooling times on the order of seconds are calculated for a 20 micron diameter silica microsphere trapped within optical tweezers, with a Doppler temperature limit in the microKelvin regime.

  14. Removal of chloroform from biodegradable therapeutic microspheres by radiolysis.

    Science.gov (United States)

    Zielhuis, S W; Nijsen, J F W; Dorland, L; Krijger, G C; van Het Schip, A D; Hennink, W E

    2006-06-06

    Radioactive holmium-166 loaded poly(l-lactic acid) microspheres are promising systems for the treatment of liver malignancies. These microspheres are loaded with holmium acetylacetonate (HoAcAc) and prepared by a solvent evaporation method using chloroform. After preparation the microspheres (Ho-PLLA-MS) are activated by neutron irradiation in a nuclear reactor. It was observed that relatively large amounts of residual chloroform (1000-6000 ppm) remained in the microspheres before neutron irradiation. Since it is known that chloroform is susceptible for high-energy radiation, we investigated whether neutron and gamma irradiation could result in the removal of residual chloroform in HoAcAc-loaded and placebo PLLA-MS by radiolysis. To investigate this, microspheres with relatively high and low amounts of residual chloroform were subjected to irradiation. The effect of irradiation on the residual chloroform levels as well as other microsphere characteristics (morphology, size, crystallinity, molecular weight of PLLA and degradation products) were evaluated. No chloroform in the microspheres could be detected after neutron irradiation. This was also seen for gamma irradiation at a dose of 200 kGy phosgene, which can be formed as the result of radiolysis of chloroform, was not detected with gas chromatography-mass spectrometry (GC-MS). A precipitation titration showed that radiolysis of chloroform resulted in the formation of chloride. Gel permeation chromatography and differential scanning calorimetry showed a decrease in molecular weight of PLLA and crystallinity, respectively. However, no differences were observed between irradiated microsphere samples with high and low initial amounts of chloroform. In conclusion, this study demonstrates that neutron and gamma irradiation results in the removal of residual chloroform in PLLA-microspheres.

  15. Porous carbon with a large surface area and an ultrahigh carbon purity via templating carbonization coupling with KOH activation as excellent supercapacitor electrode materials

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Liu, Xin; Pi, Xinxin; Yang, Yuqi; Wu, Shaohua

    2016-11-01

    Large surface area and good structural stability, for porous carbons, are two crucial requirements to enable the constructed supercapacitors with high capacitance and long cycling lifespan. Herein, we successfully prepare porous carbon with a large surface area (3175 m2 g-1) and an ultrahigh carbon purity (carbon atom ratio of 98.25%) via templating carbonization coupling with KOH activation. As-synthesized MTC-KOH exhibits excellent performances as supercapacitor electrode materials in terms of high specific capacitance and ultrahigh cycling stability. In a three electrode system, MTC-KOH delivers a high capacitance of 275 F g-1 at 0.5 A g-1 and still 120 F g-1 at a high rate of 30 A g-1. There is almost no capacitance decay even after 10,000 cycles, demonstrating outstanding cycling stability. In comparison, pre-activated MTC with a hierarchical pore structure shows a better rate capability than microporous MTC-KOH. Moreover, the constructed symmetric supercapacitor using MTC-KOH can achieve high energy densities of 8.68 Wh kg-1 and 4.03 Wh kg-1 with the corresponding power densities of 108 W kg-1 and 6.49 kW kg-1, respectively. Our work provides a simple design strategy to prepare highly porous carbons with high carbon purity for supercapacitors application.

  16. Doped zinc oxide microspheres

    Science.gov (United States)

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  17. Polyvinyl pyridine microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1980-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  18. In vitro and In vivo assessment of lawsone microsphere loaded chitosan scaffolds

    Directory of Open Access Journals (Sweden)

    Jamal Basha D

    2016-09-01

    Full Text Available Objective: To prepare, assess the lawsone loaded chitosan scaffolds for antibacterial and wound healing activity.Methods: The work was focused is to develop a topical formulation preferably, natural biodegradable scaffolds of lawsone drug for treating skin wounds and bacterial infections. Here, lawsone loaded chitosan microspheres were impregnated into chitosan scaffolds. The lawsone microspheres prepared by emulsification and cross linking method. Incorporation of lawsone loaded chitosan microspheres into chitosan scaffolds by emulsification and freeze drying technique. The lawsone a microspheres characterized by FT-IR, SEM, evaluated through entrapment efficiency, percentage yield, in vitro drug release studies. Lawsone scaffolds was assessed for wound healing ability using albino rats and anti bacterial activity by agar disc diffusion method.Results: the FT-IR spectra showing almost similar peaks within the same wave length range indicating the there is no possible interaction between the drug and polymer. The SEM of Lawsone microspheres and prepared scaffolds showing oval shape, slightly rough, porous surface, slightly aggregated and interconnected porous structure of the scaffolds was slightly reddish brown in colour. The lawsone loaded chitosan scaffolds had exhibited antibacterial activity against different bacrial strains and wound healing potential in albino rats.Conclusion:  The schematic process of lawsone loaded chitosan microspheres imparts quality in the in the topical formulation and obtained results were judicious.

  19. Microfluidic one-step synthesis of alginate microspheres immobilized with antibodies

    Science.gov (United States)

    Chen, Wanyu; Kim, Jong-Hoon; Zhang, Di; Lee, Kyong-Hoon; Cangelosi, G. A.; Soelberg, S. D.; Furlong, C. E.; Chung, Jae-Hyun; Shen, Amy Q.

    2013-01-01

    Micrometre- and submicrometre-size functionalized beads are frequently used to capture targets of interest from a biological sample for biological characterizations and disease diagnosis. The main challenge of the microbead-based assay is in the immobilization of probe molecules onto the microbead surfaces. In this paper, we report a versatile droplet microfluidics method to fabricate alginate microspheres while simultaneously immobilizing anti-Mycobacterium tuberculosis complex IgY and anti-Escherichia coli IgG antibodies primarily on the porous alginate carriers for specific binding and binding affinity tests. The binding affinity of antibodies is directly measured by fluorescence intensity of stained target bacteria on the microspheres. We demonstrate that the functionalized alginate microspheres yield specificity comparable with an enzyme-linked immunosorbent assay. The high surface area-to-volume ratio of the functionalized porous alginate microspheres improves the detection limit. By using the droplet microfluidics, we can easily modify the size and shape of alginate microspheres, and increase the concentration of functionalized alginate microspheres to further enhance binding kinetics and enable multiplexing. PMID:23966617

  20. PLGA Microspheres Incorporated Gelatin Scaffold: Microspheres Modulate Scaffold Properties

    OpenAIRE

    Indranil Banerjee; Debasish Mishra; Maiti, Tapas K.

    2009-01-01

    Freeze drying is one of the popular methods of fabrication for poly(lactide-co-glycolide) (PLGA) microspheres incorporated polymer scaffolds. However, the consequence of microspheres incorporation on physical and biological properties of scaffold has not been studied yet. In this study, attempt has been made to characterize the effect of PLGA microsphere incorporation on the physical properties of freeze-dried gelatin scaffold and its influence on cytocompatibility. Scaffolds loaded with va...

  1. Preparation of Bauxite Ceramic Microsphere

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaosu; LIU Pingan; LI Xiuyan; SHUI Anze; ZENG Lingke

    2007-01-01

    Ceramic microspheres were prepared by using Chinese bauxite as raw materials through the centrifugal spray drying method. The control technology of microsphere size, degree of sphericity was researched. The ceramic microspheres were sintered by a double sintering process. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy spectroscopy. The results show that the degree of sphericity of the ceramic microsphere was good and the particle size was 10-100 μm. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere was α- Al2O3 and mullite (3Al2O3·2SiO2). The product can be used as reinforced material for composite material, especially for antiskid and hard wearing aluminum alloy coating.

  2. Preparation and characterization of PS/pAPBA core-shell microspheres

    Institute of Scientific and Technical Information of China (English)

    Changling YAN; Yan LU; Shuyan GAO

    2009-01-01

    Polystyrene microspheres with an average diameter of 55 μm were prepared by suspension polymerization via oxidation of the monomer by ammonium persulfate. Poly-3-aminophenylboronic acid was grafted onto the surfaces of the polystyrene microspheres to form polystyrene/poly-3-aminophenylboronic acid core- shell micospheres. The samples were characterized by scanning electron microscopy, Raman spectroscopy, X-ray photo-electron spectroscopy and nitrogen adsorption/desorption method. The results show that poly-3-aminophenylboronic acid was successfully grafted to the surfaces of the polystyrene microspheres by aromatic ring electron-pairing interaction. The surfaces of the core-shell micro-spheres possessed a porous structure, with the average pore diameter of 30.2 nm and the BET surface area of 193.26 m2/g.

  3. Synthesis and characterization of magnetic polymer microspheres with a core-shell structure

    Institute of Scientific and Technical Information of China (English)

    Ming; Lu; Shu; Bai; Kun; Yang; Yan; Sun

    2007-01-01

    Non-porous magnetic polymer microspheres with a core-shell structure were prepared by a novel micro-suspension polymerization technique.A stable iron oxide ferrofluid was used to supply the magnetic core, and the polymeric shell was made of glycidyl methacrylate (GMA monomer)and ethylene dimethacrylate (cross-linker). In the preparation, polyvinyl alcohol was used as the stabilizer, and a lauryl alcohol mixture as the dispersant. The influence of various conditions such as aqueous phase volume, GMA and initiator amounts, reaction time and stirring speed on the character of the microspheres was investigated. The magnetic microspheres were then characterized briefly. The results indicate that the microspheres with active epoxy groups had a narrow size distribution range from 1 to 10 μm with a volume-weighted mean diameter of 4.5 μm.The saturation magnetization reached 19.9 emu/g with little coercivity and remanence.

  4. Perfluoroalkyl-Functionalized Hyperbranched Polyglycerol as Pore Forming Agents and Supramolecular Hosts in Polymer Microspheres

    Directory of Open Access Journals (Sweden)

    Olaf Wagner

    2015-08-01

    Full Text Available Perfluoroalkyl-functionalized, hyperbranched polyglycerols that produce stable microbubbles are integrated into a microfluidic emulsion to create porous microspheres. In a previously-presented work a dendrimer with a perfluorinated shell was used. By replacing this dendrimer core with a hyperbranched core and evaluating different core sizes and degrees of fluorinated shell functionalization, we optimized the process to a more convenient synthesis and higher porosities. The new hyperbranched polyglycerol porogens produced more pores and can be used to prepare microspheres with porosity up to 12% (v/v. The presented preparation forms pores with a perfluoroalkyl-functionalized surface that enables the resulting microspheres to act as supramolecular host systems. The microspheres can incorporate gases into the pores and actives in the polymer matrix, while the perfluoroalkylated pore surface can be used to immobilize perfluoro-tagged molecules onto the pores by fluorous-fluorous interaction.

  5. Isocratic and gradient impedance plot analysis and comparison of some recently introduced large size core-shell and fully porous particles.

    Science.gov (United States)

    Vanderheyden, Yoachim; Cabooter, Deirdre; Desmet, Gert; Broeckhoven, Ken

    2013-10-18

    The intrinsic kinetic performance of three recently commercialized large size (≥4μm) core-shell particles packed in columns with different lengths has been measured and compared with that of standard fully porous particles of similar and smaller size (5 and 3.5μm, respectively). The kinetic performance is compared in both absolute (plot of t0 versus the plate count N or the peak capacity np for isocratic and gradient elution, respectively) and dimensionless units. The latter is realized by switching to so-called impedance plots, a format which has been previously introduced (as a plot of t0/N(2) or E0 versus Nopt/N) and has in the present study been extended from isocratic to gradient elution (where the impedance plot corresponds to a plot of t0/np(4) versus np,opt(2)/np(2)). Both the isocratic and gradient impedance plot yielded a very similar picture: the clustered impedance plot curves divide into two distinct groups, one for the core-shell particles (lowest values, i.e. best performance) and one for the fully porous particles (highest values), confirming the clear intrinsic kinetic advantage of core-shell particles. If used around their optimal flow rate, the core-shell particles displayed a minimal separation impedance that is about 40% lower than the fully porous particles. Even larger gains in separation speed can be achieved in the C-term regime.

  6. Fabrication of the novel core-shell MCM-41@mTiO{sub 2} composite microspheres with large specific surface area for enhanced photocatalytic degradation of dinitro butyl phenol (DNBP)

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao-Na; Wang, Hui-Long, E-mail: hlwang@dlut.edu.cn; Li, Zhen-Duo; Huang, Zhi-Qiang; Qi, Hui-Ping; Jiang, Wen-Feng

    2016-05-30

    Graphical abstract: The mesoporous MCM-41@mTiO{sub 2} composite microspheres with core/shell structure, well-crystallized mesoporous TiO{sub 2} layer, high specific surface, large pore volume and excellent photocatalytic activity were synthesized by combining sol-gel and simple hydrothermal treatment. - Highlights: • The mesoporous MCM-41@mTiO{sub 2} composite was synthesized successfully. • The composite was facilely prepared by combining sol-gel and hydrothermal method. • The composite exhibited high photocatalytic degradation activity for DNBP. • The composite photocatalyst has excellent reproducibility. - Abstract: The mesoporous MCM-41@mTiO{sub 2} core-shell composite microspheres were synthesized successfully by combining sol-gel and simple hydrothermal treatment. The morphology and microstructure characteristics of the synthesized materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurements, X-ray powder diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis/DRS) and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the composite material possesses obvious core/shell structure, a pure mesoporous and well-crystallized TiO{sub 2} layer (mTiO{sub 2}), high specific surface area (316.8 m{sup 2}/g), large pore volume (0.42 cm{sup 3}/g) and two different pore sizes (2.6 nm and 11.0 nm). The photocatalytic activity of the novel MCM-41@mTiO{sub 2} composite was evaluated by degrading 2-sec-butyl-4,6-dinitrophenol (DNBP) in aqueous suspension under UV and visible light irradiation. The results were compared with commercial anatase TiO{sub 2} and Degussa P25 and the enhanced degradation were obtained with the synthesized MCM-41@mTiO{sub 2} composite under the same conditions, which meant that this material can serve as an efficient photocatalyst for the degradation of hazardous organic pollutants in wastewaters.

  7. Sub-wavelength image stitching with removable microsphere-embedded thin film

    Science.gov (United States)

    Du, Bintao; Ye, Yong-Hong; Hou, Jinglei; Guo, Minglei; Wang, Tian

    2016-01-01

    Imaging by dielectric microspheres embedded in thin film is a simple technique to achieve optical super-resolution. However, the film-thickness effect has not caused enough attention, and its field of view (FOV) is very limited. We first introduce a method to fabricate barium titanate glass (BTG) microsphere-embedded ultrathin polydimethylsiloxane (PDMS) films, and study their sub-wavelength imaging properties as a function of the film thickness. Our experimental results reveal that for an individual microsphere, its FOV obviously increases as the film thickness decreases, while the corresponding magnification changes barely. When the PDMS film thickness is 5-10 μm, the FOV of a microsphere is the largest, and the images produced by the neighboring close-packed microspheres with the same size can be stitched together to form a large image, realizing effective view expansion. Our results will boost the practical capacity of BTG microsphere-embedded film for sub-wavelength imaging.

  8. Miniaturized catalysis: monolithic, highly porous, large surface area capillary flow reactors constructed in situ from polyhedral oligomeric silsesquioxanes (POSS).

    Science.gov (United States)

    Scholder, P; Nischang, I

    2015-08-21

    A single-step molding process utilizing free-radical cross-linking reaction of vinyl POSS in microliter-sized dimensions leads to hierarchically-structured, mechanically robust, porous hybrid structures. Functional variants show excellent performance in Suzuki-type coupling reactions. Due to their small volume, long-term operational robustness, and potential chemical diversity, these materials are promising candidates for catalyst screening applications.

  9. Room-temperature attachment of PLGA microspheres to titanium surfaces for implant-based drug release

    Science.gov (United States)

    Xiao, Dongqin; Liu, Qing; Wang, Dongwei; Xie, Tao; Guo, Tailin; Duan, Ke; Weng, Jie

    2014-08-01

    Drug release from implant surfaces is an effective approach to impart biological activities, (e.g., antimicrobial and osteogenic properties) to bone implants. Coatings of polylactide-based polymer are a candidate for this purpose, but a continuous (fully covering) coating may be non-optimal for implant-bone fixation. This study reports a simple room-temperature method for attaching poly (lactide-co-glycolide) (PLGA) microspheres to titanium (Ti) surfaces. Microspheres were prepared with polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) as the emulsifier. Microspheres were attached to Ti discs by pipetting as a suspension onto the surfaces followed by vacuum drying. After immersion in shaking water bath for 14 d, a substantial proportion of the microspheres remained attached to the discs. In contrast, if the vacuum-drying procedure was omitted, only a small fraction of the microspheres remained attached to the discs after immersion for only 5 min. Microspheres containing triclosan (a broad-spectrum antibiotic) were attached by porous-surfaced Ti discs. In vitro experiments showed that the microsphere-carrying discs were able to kill Staphylococcus aureus and Escherichia Coli, and support the adhesion and growth of primary rat osteoblasts. This simple method may offer a flexible technique for bone implant-based drug release.

  10. Comparative assessment of in vitro release kinetics of calcitonin polypeptide from biodegradable microspheres.

    Science.gov (United States)

    Prabhu, Sunil; Sullivan, Jennifer L; Betageri, Guru V

    2002-01-01

    The objective of our study was to compare the in vitro release kinetics of a sustained-release injectable microsphere formulation of the polypeptide drug, calcitonin (CT), to optimize the characteristics of drug release from poly-(lactide-co-glycolide) (PLGA) copolymer biodegradable microspheres. A modified solvent evaporation and double emulsion technique was used to prepare the microspheres. Release kinetic studies were carried out in silanized tubes and dialysis bags, whereby microspheres were suspended and incubated in phosphate buffered saline, sampled at fixed intervals, and analyzed for drug content using a modified Lowry protein assay procedure. An initial burst was observed whereby about 50% of the total dose of the drug was released from the microspheres within 24 hr and 75% within 3 days. This was followed by a period of slow release over a period of 3 weeks in which another 10-15% of drug was released. Drug release from the dialysis bags was more gradual, and 50% CT was released only after 4 days and 75% after 12 days of release. Scanning electron micrographs revealed spherical particles with channel-like structures and a porous surface after being suspended in an aqueous solution for 5 days. Differential scanning calorimetric studies revealed that CT was present as a mix of amorphous and crystalline forms within the microspheres. Overall, these studies demonstrated that sustained release of CT from PLGA microspheres over a 3-week period is feasible and that release of drug from dialysis bags was more predictable than from tubes.

  11. Preparation, Characterization, and Bioactivity of Chitosan Microspheres Containing Basic Fibroblast Growth Factor

    Directory of Open Access Journals (Sweden)

    Bo Lv

    2014-01-01

    Full Text Available The aim of this study is to evaluate, prepare, and characterize bioactivity of chitosan microspheres loaded with bFGF for providing sustained release of bFGF. Porous chitosan microspheres were prepared by freeze-drying process based on the interaction between chitosan and tripolyphosphate (TPP. The bFGF-loaded chitosan microspheres were well interconnected and have a narrow size distribution, spherical shape, and positive surface charges. The bFGF-loading capacity and encapsulation efficiency were 7.57 mg/g and 95.1%, respectively. Results of in vitro release showed that the extent of release was 82.1% at Day 25. Schwann cells were used as an in vitro model for cell response to bFGF and bFGF-loaded chitosan microspheres. Results indicated that the number, cell viability, and percentage of cells G2/M+S phase in the bFGF groups are higher than those in the bFGF-loaded chitosan microspheres groups before culturing for 2 days. However, the number, cell viability, and percent of cells G2/M+S phase in the bFGF-loaded chitosan microspheres groups are significantly higher than those in the bFGF groups after culture for 4 and 8 days. These findings indicated that bFGF-loaded chitosan microspheres may help to decrease the release of bFGF and provide a suitable three-dimensional environment for cell growth and proliferation.

  12. Novel Self-Assembly-Induced Gelation for Nanofibrous Collagen/Hydroxyapatite Composite Microspheres

    Directory of Open Access Journals (Sweden)

    Jae-Won Choi

    2017-09-01

    Full Text Available This study demonstrates the utility of the newly developed self-assembly-induced gelation technique for the synthesis of porous collagen/hydroxyapatite (HA composite microspheres with a nanofibrous structure. This new approach can produce microspheres of a uniform size using the droplets that form at the nozzle tip before gelation. These microspheres can have a highly nanofibrous structure due to the immersion of the droplets in a coagulation bath (water/acetone, in which the collagen aggregates in the solution can self-assemble into fibrils due to pH-dependent precipitation. Bioactive HA particles were incorporated into the collagen solutions, in order to enhance the bioactivity of the composite microspheres. The composite microspheres exhibited a well-defined spherical morphology and a uniform size for all levels of HA content (0 wt %, 10 wt %, 15 wt %, and 20 wt %. Collagen nanofibers—several tens of nanometers in size—were uniformly present throughout the microspheres and the HA particles were also well dispersed. The in vitro apatite-forming ability, assessed using the simulated body fluid (SBF solution, increased significantly with the incorporation of HA into the composite microspheres.

  13. Double walled POE/PLGA microspheres: encapsulation of water-soluble and water-insoluble proteins and their release properties.

    Science.gov (United States)

    Shi, Meng; Yang, Yi-Yan; Chaw, Cheng-Shu; Goh, Suat-Hong; Moochhala, Shabbir M; Ng, Steve; Heller, Jorge

    2003-04-29

    The poly(orthoester) (POE)-poly(D,L-lactide-co-glycolide) (50:50) (PLGA) double-walled microspheres with 50% POE in weight were loaded with hydrophilic bovine serum albumin (BSA) and hydrophobic cyclosporin A (CyA). Most of the BSA and CyA was entrapped within the shell and core, respectively, because of the difference in their hydrophilicity. The morphologies and release mechanisms of proteins-loaded double-walled POE/PLGA microspheres were investigated. Scanning electron microscope studies revealed that the CyA-BSA-loaded double-walled POE/PLGA microspheres yielded a more porous surface and PLGA shell than those without BSA. The neat POE and PLGA yielded slow and incomplete CyA and BSA release. In contrast, nearly complete BSA and more than 95% CyA were released in a sustained manner from the double-walled POE/PLGA microspheres. Both the BSA- and CyA-BSA-loaded POE/PLGA microspheres yielded a sustained BSA release over 5 days. The CyA release pattern of the CyA-loaded double-walled POE/PLGA microspheres was biphasic, characterized by a slow release over 15 days followed by a sustained release over 27 days. However, the CyA-BSA-loaded double-walled POE/PLGA microspheres provided a more constant and faster CyA release due to their more porous shell. In the CyA-BSA-loaded double-walled POE/PLGA microspheres system, the PLGA layer acted as a carrier for BSA and mild reservoir for CyA. During the first 5 days, most BSA was released from the shell but only 14% CyA was left from the microspheres. Subsequently, more than 80% CyA were released in the next 25 days. The distinct structure of double-walled POE/PLGA microspheres would make an interesting device for controlled delivery of therapeutic agents.

  14. Porogen effects in synthesis of uniform micrometer-sized poly(divinylbenzene) microspheres with high surface areas.

    Science.gov (United States)

    Hao, Dong-xia; Gong, Fang-ling; Wei, Wei; Hu, Guo-hua; Ma, Guang-hui; Su, Zhi-guo

    2008-07-01

    A new method of synthesizing uniform poly(divinylbenzene) (polyDVB) microspheres with high specific surface areas was designed by combining Shirasu porous glass (SPG) membrane emulsification, suspension polymerization, and post-crosslinking techniques. It was shown that the physicochemical properties of porogens have a great influence on the size distribution and porous features of microspheres. The low aqueous solubility of porogen facilitated preparation of uniform emulsions and microspheres, and high aqueous solubility led to polydispersed emulsions and poor microsphere yields. Such aqueous solubility effects can be tailored by adding a low molecular weight polystyrene (LPST) as costabilizer in porogen, thus improving the uniformity of microspheres. Moreover, different affinities of porogens for copolymers demonstrate various contributions to specific surface areas of microspheres in suspension polymerization especially post-crosslinking. Solvating porogen requires a much higher addition than nonsolvating porogen to obtain equal specific surface areas in polymerization, but has more potential to enhance the specific surface area in post-crosslinking. Two kinds of uniform microspheres were obtained with high specific surface areas, up to 706.6 m2/g by heptane and 937.5 m2/g by toluene.

  15. Functional magnetic microspheres

    Science.gov (United States)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Landel, Robert F. (Inventor)

    1981-01-01

    Functional magnetic particles are formed by dissolving a mucopolysaccharide such as chitosan in acidified aqueous solution containing a mixture of ferrous chloride and ferric chloride. As the pH of the solution is raised magnetite is formed in situ in the solution by raising the pH. The dissolved chitosan is a polyelectrolyte and forms micelles surrounding the granules at pH of 8-9. The chitosan precipitates on the granules to form microspheres containing the magnetic granules. On addition of the microspheres to waste aqueous streams containing dissolved ions, the hydroxyl and amine functionality of the chitosan forms chelates binding heavy metal cations such as lead, copper, and mercury and the chelates in turn bind anions such as nitrate, fluoride, phosphate and borate.

  16. Facile preparation of novel dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes for excellent capacitive property in asymmetric supercapacitors

    Science.gov (United States)

    Liu, Li; Zhang, Huijuan; Fang, Ling; Mu, Yanping; Wang, Yu

    2016-09-01

    In this work, we successfully synthesized the dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes (Fe-NCO-M@N-1h) using a facile hydrothermal method, followed by calcinations. In the unique structure, numerous nanoneedles radially grow on the surface of microsphere and some porous nanomeshes orderly develop in the inside of microsphere, therefore dandelion-like Fe-NCO-M@N-1h displays large specific surface area (101.15 m2 g-1) and more active sites. Electrochemical properties of the Fe-NCO-M@N-1h have been tested for symmetric supercapacitors (SCs) and asymmetric supercapacitors (ASCs). Benefiting from the structural advantages, Fe-NCO-M@N-1h electrode exhibits outstanding capacitive behaviors, such as the desirable specific capacitance and eminent rate performance (2237 and 1810 F g-1 at the current densities of 1 and 20 A g-1, respectively) and remarkable cycling performance (95.8% retention after 4500 cycles). Besides, a Fe-NCO-M@N-1h//AC-ASCs device has been constructed successfully, presenting the highest energy density of 46.68 Wh kg-1. The results indicate that the Fe-NCO-M@N-1h is a potential material for SCs.

  17. Fabrication of large-area self-organizing gold nanostructures on a porous Al2O3 template for application as a SERS-substrate

    DEFF Research Database (Denmark)

    Nielsen, Peter; Hassing, Søren; Albrektsen, Ole;

    A new technique for fabrication of large-area self-organizing variably ordered gold nanostructures with sub-10 nm gaps on templates of hexagonally ordered porous anodic aluminum oxide is demonstrated. The size as well as the interparticle distance of the fabricated gold nanostructures are adjusted...... by application of various electrolytes used in anodization of the aluminum template and the thickness of gold sputter-coated on the pore layer. The fabricated substrates are characterized by SEM, and the applicability as SERS substrates is investigated by adsorption of rhodamine 6G on the nanostructures...

  18. Hollow mesoporous titania microspheres: New technology and enhanced photocatalytic activity

    Science.gov (United States)

    Feng, Zhenliang; Wei, Wenrui; Wang, Litong; Hong, Ruoyu

    2015-12-01

    Hollow titania microspheres (HTS) were fabricated via a sol-gel process by coating the hydrolysis product of titanium tetrabutoxide (TBOT) onto the amino (-NH2) modified porous polystyrene cross-linked divinyl benzene (PS-DVB) microspheres under changing atmospheric pressure, followed by calcination in nitrogen and air atmosphere. Particularly, the atmospheric pressure was continuously and regularly changed during the formation process of PS-DVB@TiO2 microspheres. Then the TiO2 particles were absorbed into the pores and onto the surface of PS-DVB as well. The resultant HTS (around 2 μm in diameter) featured a high specific surface area (84.37 m2/g), anatase crystal and stable hollow microsphere structure, which led to high photocatalysis activity. The photocatalytic degradation of malachite green (MG) organic dye solution was conducted under ultraviolet (UV) light irradiation, which showed a high photocatalytic ability (81% of MG was degraded after UV irradiation for 88 min). Therefore, it could be potentially applied for the treatment of wastewater contaminated by organic pollutants.

  19. Chitosan-Montmorillonite microspheres: A sustainable fertilizer delivery system.

    Science.gov (United States)

    dos Santos, Bruna Rodrigues; Bacalhau, Fabiana Britti; Pereira, Tamires dos Santos; Souza, Claudinei Fonseca; Faez, Roselena

    2015-08-20

    Controlled release fertilizers are efficient tools that increase the sustainability of agricultural practices. However, the biodegradability of the matrices and the determination of the release into soil still require some investigation. This paper describes the preparation of potassium-containing microspheres based on chitosan and montmorillonite clay and the in situ soil release. The chitosan-montmorillonite microspheres were prepared using a coagulation method and different proportions of montmorillonite. The structural, thermal and morphological properties as well the water swelling and fertilizer sorption capacity were evaluated. The best formulations were applied in soil, and the fertilizer release was monitored using time-domain reflectometry (TDR). Montmorillonite clay provides better sorption properties than the chitosan microspheres because of the rough and porous surface. Due to these properties, high levels of fertilizer were sorbed onto the material. ChMMT33-containing potassium shows two specific periods of fertilizer release: the first one lasted approximately three days and was assigned to the external fertilizer on the microspheres. The second was assigned to the internal fertilizer. TDR is an important and fast tool and was used to determine the fertilizer release and the ion movement in the soil.

  20. Fabrication of the novel core-shell MCM-41@mTiO2 composite microspheres with large specific surface area for enhanced photocatalytic degradation of dinitro butyl phenol (DNBP)

    Science.gov (United States)

    Wei, Xiao-Na; Wang, Hui-Long; Li, Zhen-Duo; Huang, Zhi-Qiang; Qi, Hui-Ping; Jiang, Wen-Feng

    2016-05-01

    The mesoporous MCM-41@mTiO2 core-shell composite microspheres were synthesized successfully by combining sol-gel and simple hydrothermal treatment. The morphology and microstructure characteristics of the synthesized materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption measurements, X-ray powder diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis/DRS) and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the composite material possesses obvious core/shell structure, a pure mesoporous and well-crystallized TiO2 layer (mTiO2), high specific surface area (316.8 m2/g), large pore volume (0.42 cm3/g) and two different pore sizes (2.6 nm and 11.0 nm). The photocatalytic activity of the novel MCM-41@mTiO2 composite was evaluated by degrading 2-sec-butyl-4,6-dinitrophenol (DNBP) in aqueous suspension under UV and visible light irradiation. The results were compared with commercial anatase TiO2 and Degussa P25 and the enhanced degradation were obtained with the synthesized MCM-41@mTiO2 composite under the same conditions, which meant that this material can serve as an efficient photocatalyst for the degradation of hazardous organic pollutants in wastewaters.

  1. Ringing phenomenon in silica microspheres

    Institute of Scientific and Technical Information of China (English)

    Chunhua Dong; Changling Zou; Jinming Cui; Yong Yang; Zhengfu Han; Guangcan Guo

    2009-01-01

    Whispering gallery modes in silica microspheres are excited by a tunable continuous-wave laser through the fiber taper. Ringing phenomenon can be observed with high frequency sweeping speed. The thermal nonlinearity in the microsphere can enhance this phenomenon. Our measurement results agree very well with the theoretical predictions by the dynamic equation.

  2. Pulp regeneration in a full-length human tooth root using a hierarchical nanofibrous microsphere system.

    Science.gov (United States)

    Li, Xiangwei; Ma, Chi; Xie, Xiaohua; Sun, Hongchen; Liu, Xiaohua

    2016-04-15

    While pulp regeneration using tissue engineering strategy has been explored for over a decade, successful regeneration of pulp tissues in a full-length human root with a one-end seal that truly simulates clinical endodontic treatment has not been achieved. To address this challenge, we designed and synthesized a unique hierarchical growth factor-loaded nanofibrous microsphere scaffolding system. In this system, vascular endothelial growth factor (VEGF) binds with heparin and is encapsulated in heparin-conjugated gelatin nanospheres, which are further immobilized in the nanofibers of an injectable poly(l-lactic acid) (PLLA) microsphere. This hierarchical microsphere system not only protects the VEGF from denaturation and degradation, but also provides excellent control of its sustained release. In addition, the nanofibrous PLLA microsphere integrates the extracellular matrix-mimicking architecture with a highly porous injectable form, efficiently accommodating dental pulp stem cells (DPSCs) and supporting their proliferation and pulp tissue formation. Our in vivo study showed the successful regeneration of pulp-like tissues that fulfilled the entire apical and middle thirds and reached the coronal third of the full-length root canal. In addition, a large number of blood vessels were regenerated throughout the canal. For the first time, our work demonstrates the success of pulp tissue regeneration in a full-length root canal, making it a significant step toward regenerative endodontics. The regeneration of pulp tissues in a full-length tooth root canal has been one of the greatest challenges in the field of regenerative endodontics, and one of the biggest barriers for its clinical application. In this study, we developed a unique approach to tackle this challenge, and for the first time, we successfully regenerated living pulp tissues in a full-length root canal, making it a significant step toward regenerative endodontics. This study will make positive scientific

  3. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

    Full Text Available Abstract Background Radiomicrosphere therapy (RT utilizing yttrium-90 (90Y microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. Methods Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. Results Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1–4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. Conclusion Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

  4. A novel porous bioceramics scaffold by accumulating hydroxyapatite spherulites for large bone tissue engineering in vivo. II. Construct large volume of bone grafts.

    Science.gov (United States)

    Zhi, Wei; Zhang, Cong; Duan, Ke; Li, Xiaohong; Qu, Shuxin; Wang, Jianxin; Zhu, Zhuoli; Huang, Peng; Xia, Tian; Liao, Ga; Weng, Jie

    2014-08-01

    In vivo engineering of bone autografts using bioceramic scaffolds with appropriate porous structures is a potential approach to prepare autologous bone grafts for the repair of critical-sized bone defects. This study investigated the evolutionary process of osteogenesis, angiogenesis, and compressive strength of bioceramic scaffolds implanted in two non-osseous sites of dogs: the abdominal cavity and the dorsal muscle. Hydroxyapatite (HA) sphere-accumulated scaffolds with controlled porous structures were prepared and placed in the two sites for up to 6 months. Analyses of retrieved scaffolds found that osteogenesis and angiogenesis were faster in scaffolds implanted in dorsal muscles compared with those placed in abdominal cavities. The abdominal cavity, however, can accommodate larger bone grafts with designed shape. Analyses of scaffolds implanted in abdominal cavities [an environment of a low mesenchymal stem cell (MSC) density] further demonstrated that angiogenesis play critical roles during osteogenesis in the scaffolds, presumably by supplying progenitor cells and/or MSCs as seed cells. This study also examined the relationship between the volume of bone grafts and the physiological environment of in vivo bioreactor. These results provide basic information for the selection of appropriate implanting sites and culture time required to engineer autologous bone grafts for the clinical bone defect repair. Based on these positive results, a pilot study has applied the grafts constructed in canine abdominal cavity to repair segmental bone defect in load-bearing sites (limbs).

  5. Preparation and characterization of PHBV microsphere/45S5 bioactive glass composite scaffolds with vancomycin releasing function.

    Science.gov (United States)

    Li, Wei; Ding, Yaping; Rai, Ranjana; Roether, Judith A; Schubert, Dirk W; Boccaccini, Aldo R

    2014-08-01

    PHBV microsphere/45S5 bioactive glass (BG) composite scaffolds with drug release function were developed for bone tissue engineering. BG-based glass-ceramic scaffolds with high porosity (94%) and interconnected pore structure prepared by foam replication method were coated with PHBV microspheres (nominal diameter=3.5 μm) produced by water-in-oil-in-water double emulsion solvent evaporation method. A homogeneous microsphere coating throughout the porous structure of scaffolds was obtained by a simple dip coating method, using the slurry of PHBV microspheres in hexane. Compressive strength tests showed that the microsphere coating slightly improved the mechanical properties of the scaffolds. It was confirmed that the microsphere coating did not inhibit the bioactivity of the scaffolds in SBF. Hydroxyapatite crystals homogeneously grew not only on the struts of the scaffolds but also on the surface of microspheres within 7 days of immersion in SBF. Vancomycin was successfully encapsulated into the PHBV microspheres. The encapsulated vancomycin was released with a dual release profile involving a relatively low initial burst release (21%) and a sustained release (1 month), which is favorable compared to the high initial burst release (77%) and short release period (4 days) measured on uncoated scaffolds. The developed bioactive composite scaffold with drug delivery function has thus the potential to be used advantageously in bone tissue engineering.

  6. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1995-08-01

    We have studied a novel extrinsic gettering method that utilizes the very large surface areas, produced by porous silicon etch on both front and back surfaces of the silicon wafer, as gettering sites. In this method, a simple and low-cost chemical etching is used to generate the porous silicon layers. Then, a high-flux solar furnace (HFSF) is used to provide high-temperature annealing and the required injection of silicon interstitials. The gettering sites, along with the gettered impurities, can be easily removed at the end the process. The porous silicon removal process consists of oxidizing the porous silicon near the end the gettering process followed by sample immersion in HF acid. Each porous silicon gettering process removes up to about 10 {mu}m of wafer thickness. This gettering process can be repeated so that the desired purity level is obtained.

  7. STRUCTURING OF DIAMOND FILMS USING MICROSPHERE LITHOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mária Domonkos

    2014-10-01

    Full Text Available In this study, the structuring of micro- and nanocrystalline diamond thin films is demonstrated. The structuring of the diamond films is performed using the technique of microsphere lithography followed by reactive ion etching. Specifically, this paper presents a four-step fabrication process: diamond deposition (microwave plasma assisted chemical vapor deposition, mask preparation (by the standard Langmuir-Blodgett method, mask modification and diamond etching. A self-assembled monolayer of monodisperse polystyrene (PS microspheres with close-packed ordering is used as the primary template. Then the PS microspheres and the diamond films are processed in capacitively coupled radiofrequency plasma  using different plasma chemistries. This fabrication method illustrates the preparation of large arrays of periodic and homogeneous hillock-like structures. The surface morphology of processed diamond films is characterized by scanning electron microscopy and atomic force microscope. The potential applications of such diamond structures in various fields of nanotechnology are also briefly discussed.

  8. Preparation of Functional Polymeric Microspheres

    Institute of Scientific and Technical Information of China (English)

    Changchun Wang; Yonghui Deng; Wuli Yang; Shoukuang Fu

    2005-01-01

    @@ 1Introduction Because of the wide applications in the area of biomedical and biotechnological fields, a great efforts have been done to fabricate different kinds of microspheres with tailored structural and surface properties over the last decade[1]. Among them, stimuli responsive microspheres are microspheres that show ability to change their physical-chemical properties and colloidal properties in response to environmental stimuli such as changes of temperature, pH, chemicals, light, electrical field, magnetic field or mechanic stress, etc. These microspheres have been under intensive study for their high potential applications in biomedical and biotechnological fields such as controlled drug delivery[2], biosensor[3], chemical isolation[4], cell culture substrates[5], enzyme immobilization[6], bioelectrocatalysis[7], and magnetically controlled electrochemical reaction[8]. However,most of the reported stimuli responsive microspheres only show response to one specific stimulus. Up to now,to the best of our knowledge, only a few works have been directed to the fabrication of microspheres which show response to more than one stimulus[9]. In this paper, a system synthesis method for stimuli responsive microspheres with more useful properties was reported, and the simple application in biomedical area have been mentioned.

  9. Fe3O4@MOF core-shell magnetic microspheres as excellent catalysts for the Claisen-Schmidt condensation reaction

    Science.gov (United States)

    Ke, Fei; Qiu, Ling-Guang; Zhu, Junfa

    2014-01-01

    Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications.Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications. Electronic supplementary information (ESI) available: SEM and TEM images, and GC-MS spectra for chalcones. See DOI: 10.1039/c3nr05051c

  10. One-step synthesis and properties of urchin-like PS/α-Fe2O3 composite hollow microspheres

    Science.gov (United States)

    Zhang, Yanping; Chu, Ying; Dong, Lihong

    2007-10-01

    A new progressive hard template method has been developed to synthesize uniform polystyrene (PS)/α-Fe2O3 composite hollow microspheres under hydrothermal conditions. Sulfonated polystyrene (PS) microspheres were used as templates as well as the endothecia of the composite microspheres; Fe2O3 shell was obtained through the reaction of FeSO4 and KClO3 under hydrothermal conditions. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies showed that the as-obtained products consist of large scale monodisperse urchin-like hollow microspheres. In comparison with the Fe2O3 of other structures, the composite hollow microspheres have good photocatalytic activity, large surface area and a high remanent magnetization. A possible mechanism for the formation of composite hollow microspheres is also proposed in the paper.

  11. A new approach to fabricate bioactive silica binary and ternary hybrid microspheres.

    Science.gov (United States)

    Angelopoulou, A; Efthimiadou, E K; Kordas, G

    2015-08-01

    Bioactive microspheres represent an extremely developing field in biomedical applications, such as bone tissue engineering and bone pathologies (metabolic bone disease, trauma or bone cancer). Their innate osteogenic properties have turned them to biomaterials with improved added value. The aim of this study was to prepare binary and ternary hybrid silica microspheres with enhanced bioactive properties according to our previous synthetic procedure. In brief, the synthetic approach based on the emulsifier free-emulsion polymerization method, by which polystyrene (PS) microspheres were produced and used as core template for the sol-gel coating method. During the coating reaction an inorganic shell was fabricated by silane and phosphate precursors (tetraethoxysilane, trimethylphosphate). The final microspheres were treated by different catalyst concentrations, during the coating process, which resulted in the formation of diffused voids (a porous-like structure). The in vitro bioactivity of the resultant microspheres was studied by treatment in simulated body fluids (SBF). The bioassay evaluation indicates the deposition of a bone-like apatite layer on microspheres' surface with enhanced bioresorbability, which verifies their bioactivity and permits their application in the treatment of bone pathologies.

  12. Mesoporous phenylalanine ammonia lyase microspheres with improved stability through calcium carbonate templating.

    Science.gov (United States)

    Cui, Jiandong; Zhao, Yamin; Tan, Zhilei; Zhong, Cheng; Han, Peipei; Jia, Shiru

    2017-05-01

    Cross-linked enzyme aggregates (CLEAs) have recently emerged as a promising method for enzyme immobilization due to its simplicity and low cost. However, a lack of good size and morphological control over the as-prepared CLEAs has limited their practical applications in some cases. Here, monodisperse spherical CLEAs of phenylalanine ammonia lyase (PAL microspheres) were prepared based on CaCO3 microtemplates. The preparation procedure involves filling porous CaCO3 microtemplates with the protein by salt precipitation, glutaraldehyde crosslinking, and dissolution of the microtemplates. The formulation of CaCO3 templates with controlled size was studied in detail. Characterization of the prepared PAL microspheres was investigated. The results showed that the PAL microspheres with high immobilization efficiency (79%) exhibited excellent stability, including increased tolerance to proteolysis, low pH, and denaturants, and excellent mechanical properties. For example, free PAL almost lost all activity after they were incubated in the presence of trypsin for 2min, whereas PAL microspheres still retained 95% of their initial activity. Moreover, scanning electron microscope, transmission electron microscope, and N2 adsorption-desorption isotherms revealed that the resultant PAL microspheres possessed good monodispersity and mesoporous structure instead of the amorphous clusters of conventional CLEAs with few pores. Compared with conventional CLEAs, the monodisperse PAL microspheres with mesoporous make them more potentially useful for biomedical and biotechnological applications.

  13. Preparation of cellulose based microspheres by combining spray coagulating with spray drying.

    Science.gov (United States)

    Wang, Qiao; Fu, Aiping; Li, Hongliang; Liu, Jingquan; Guo, Peizhi; Zhao, Xiu Song; Xia, Lin Hua

    2014-10-13

    Porous microspheres of regenerated cellulose with size in range of 1-2 μm and composite microspheres of chitosan coated cellulose with size of 1-3 μm were obtained through a two-step spray-assisted approach. The spray coagulating process must combine with a spray drying step to guarantee the formation of stable microspheres of cellulose. This approach exhibits the following two main virtues. First, the preparation was performed using aqueous solution of cellulose as precursor in the absence of organic solvent and surfactant; Second, neither crosslinking agent nor separated crosslinking process was required for formation of stable microspheres. Moreover, the spray drying step also provided us with the chance to encapsulate guests into the resultant cellulose microspheres. The potential application of the cellulose microspheres acting as drug delivery vector has been studied in two PBS (phosphate-buffered saline) solution with pH values at 4.0 and 7.4 to mimic the environments of stomach and intestine, respectively.

  14. [Preparation and clinical application of polyvinyl alcohol/drug-loaded chitosan microsphere composite wound dressing].

    Science.gov (United States)

    Zhang, Xiuju; Lin, Zhidan; Chen, Wenbin; Song, Ying; Li, Zhizhong

    2011-04-01

    In order to prepare and apply the polyvinyl alcohol/drug-loaded chitosan microspheres composite wound dressing, we first prepared chitosan microspheres by emulsion cross-linking method, and then added chitosan microspheres into the reactants during the acetalization of polyvinyl alcohol and formaldehyde. We further studied the morphology, water absorption, swelling degree, mechanical properties and in vitro release of the sponge with different amount of chitosan microspheres. The results showed that polyvinyl alcohol/drug-loaded chitosan composite sponge has porous structure with connectionism. Increasing the amount of chitosan microspheres would make the apertures smaller, so that the water absorption and the swelling of sponge decreased, but the tensile strength and compressive strength increased. With the increase of the amount of chitosan microspheres, the drug absorption of cefradine and the release rate increase, and the release time become longer. With the results of toxicity grade of 0 to 1, this type of composite sponge is non-toxic and meets the requirement of biocompatibility. The observation of rabbit nasal cavity after surgical operation suggested that polyvinyl acetal sponge modified with the chitosan has antiphlogistic, hemostatic and non-adherent characteristic, and can promote the healing and recovering of the nasalmucosa. After using this composite material, best growing surroundings for patients' granulation tissue were provided. Exposed bone and tendon were covered well with granulation tissue.

  15. Mucoadhesive Microsphere - Review

    Directory of Open Access Journals (Sweden)

    Ratnaparkhi M P

    2014-06-01

    Full Text Available Several approaches have been immerged to prolong the residence time of the dosage forms at the absorption site and one of them is the development of oral controlled release mucoadhesive system. Mucoadhesive drug delivery systems are used to enhance drug absorption in a site-specific manner. Bioadhesion has been defined as the attachment of synthetic or biological macromolecules to a biological tissue. The biological surface can be epithelial tissue or the mucous coat on the surface of a tissue. If adhesive attachment is to a mucous coat, the phenomenon is referred to as mucoadhesion. Mucus is a thin blanket covering all epithelia that are in contact with the external environment in the gastrointestinal, respiratory, and urogenital tracts. This approach involves the use of mucoadhesive polymers, which can adhere to the epithelial surface in the stomach. Carrier technology offers an intelligent approach for drug delivery by coupling the drug to a carrier particle such as microspheres, nanospheres, liposomes, nanoparticles, etc., which modulates the release and absorption of the drug. Microspheres constitute an important part of these particulate drug delivery systems by virtue of their small size and efficient carrier capacity.

  16. Preparation, characterization and in vitro release study of BSA-loaded double-walled glucose-poly(lactide-co-glycolide) microspheres.

    Science.gov (United States)

    Ansary, Rezaul H; Rahman, Mokhlesur M; Awang, Mohamed B; Katas, Haliza; Hadi, Hazrina; Mohamed, Farahidah; Doolaanea, Abd Almonem; Kamaruzzaman, Yunus B

    2016-09-01

    The aim of this study was to prepare a model protein, bovine serum albumin (BSA) loaded double-walled microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA) and a moderate-degrading carboxyl-terminated PLGA polymers to reduce the initial burst release and to eliminate the lag phase from the release profile of PLGA microspheres. The double-walled microspheres were prepared using a modified water-in-oil-in-oil-in-water (w/o/o/w) method and single-polymer microspheres were prepared using a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The particle size, morphology, encapsulation efficiency, thermal properties, in vitro drug release and structural integrity of BSA were evaluated in this study. Double-walled microspheres prepared with Glu-PLGA and PLGA polymers with a mass ratio of 1:1 were non-porous, smooth-surfaced, and spherical in shape. A significant reduction of initial burst release was achieved for the double-walled microspheres compared to single-polymer microspheres. In addition, microspheres prepared using Glu-PLGA and PLGA polymers in a mass ratio of 1:1 exhibited continuous BSA release after the small initial burst without any lag phase. It can be concluded that the double-walled microspheres made of Glu-PLGA and PLGA polymers in a mass ratio of 1:1 can be a potential delivery system for pharmaceutical proteins.

  17. Formulation and characterization of microspheres loaded with imatinib for sustained delivery.

    Science.gov (United States)

    Ramazani, F; Chen, W; Van Nostrum, C F; Storm, G; Kiessling, F; Lammers, T; Hennink, W E; Kok, R J

    2015-03-30

    The aim of this study was the development of imatinib-loaded poly(d,l-lactide-co-glycolide) (PLGA) microspheres with high loading efficiency which can afford continuous release of imatinib over a prolonged period of time. Imatinib mesylate loaded PLGA microspheres with a size of 6-20 μm were prepared by a double emulsion (W1/O/W2) method using dichloromethane as volatile solvent. It was found that the microspheres were spherical with a non-porous surface; imatinib loading efficiency (LE) was highly dependent on the pH of the external water phase (W2). By increasing the pH of W2 phase above the highest pKa of imatinib (pKa 8.1), at which imatinib is mainly uncharged, the LE increased from 10% to 90% (pH 5.0 versus pH 9.0). Conversely, only 4% of its counter ion, mesylate, was retained in the microspheres at the same condition (pH 9.0). Since mesylate is highly water soluble, it is unlikely that it partitions into the organic phase. We demonstrated, using differential scanning calorimetry (DSC), that imatinib was molecularly dispersed in the polymeric matrix at loadings up to 8.0%. At higher drug loading, imatinib partially crystallized in the matrix. Imatinib microspheres released their cargo during three months by a combination of diffusion through the polymer matrix and polymer erosion. In conclusion, we have formulated imatinib microspheres with high LE and LC. Although we started with a double emulsion of imatinib mesylate, the obtained microspheres contained imatinib base which was mainly molecularly dispersed in the polymer matrix. These microspheres release imatinib over a 3-month period which is of interest for local treatment of cancer.

  18. Encapsulation of azithromycin into polymeric microspheres by reduced pressure-solvent evaporation method.

    Science.gov (United States)

    Li, Xiujuan; Chang, Si; Du, Guangsheng; Li, Yi; Gong, Junbo; Yang, Mingshi; Wei, Zhenping

    2012-08-20

    Azithromycin loaded microspheres with blends of poly-l-lactide and ploy-D,L-lactide-co-glycolide as matrices were prepared by the atmosphere-solvent evaporation (ASE) and reduced pressure-solvent evaporation (RSE) method. Both the X-ray diffraction spectra and DSC thermographs demonstrated that poly-L-lactide existed in a crystalline form in the ASE microspheres, while an amorphous form was present in the RSE formulations. Besides, solvent removal at atmosphere gave microspheres of porous and rough surfaces, but smooth surfaces appeared in the RSE microspheres. The incorporation efficiency as well as the burst release (cumulative release in the first 24h) in the ASE formulations was 39.94 ± 1.18% and 23.96 ± 2.01% respectively, yet the encapsulation efficiency of the microspheres fabricated under 385 mmHg was high up to 57.19 ± 3.81% and the burst release was 4.12 ± 0.15%. The in vitro drug release studies indicated that the ASE microspheres presented a zero-order profile; while the RSE formulations followed first-order kinetics. Other factors including solidification time, temperature, drug to polymer ratio and pH value of the continuous phase could also influence the physicochemical characteristics and release profiles of microspheres. In conclusion, the overall improvement of microspheres in appearance, encapsulation efficiency and controlled drug release through the RSE method could be easily fulfilled under optimal preparation conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Synthesis of Bi2WO6 Microspheres with Visible-Light Photocatalytic Properties

    Science.gov (United States)

    Wan, Gengping; Wang, Guizhen

    2013-12-01

    Bi2WO6 microspheres constructed from nanosheets have been synthesized by a controllable solvothermal route in a large scale. The structure characterizations of the microspheres were investigated in detail by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). On the basis of XRD analysis and SEM observation of the products at different reaction time periods, a growth mechanism of Bi2WO6 microspheres was proposed. UV-Visible diffuse reflectance (DR) spectrum of the prepared Bi2WO6 microspheres demonstrates that they have absorption in the visible light region. The photocatalytic activity of Bi2WO6 microspheres toward Rhodamine-B (RhB) degradation was investigated and the as-prepared products exhibited good photocatalytic activity in degradation of RhB under 300 W Xe lamp light irradiation.

  20. Optical diffraction by ordered 2D arrays of silica microspheres

    Science.gov (United States)

    Shcherbakov, A. A.; Shavdina, O.; Tishchenko, A. V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-03-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality.

  1. Multifrequency transverse Faraday effect in single magneto-dielectric microspheres

    CERN Document Server

    Maksymov, Ivan S

    2014-01-01

    We propose using a single magneto-dielectric microsphere as a device for enhancing the transverse Faraday effect at multiple wavelengths at the same time. Although the diameter of the sphere can be $<1$ $\\mu$m, the numerically predicted strength of its magneto-optical (MO) response can be an order of magnitude stronger than in MO devices based on thick magnetic plates. The MO response of a microsphere is also comparable with that of subwavelength magneto-dielectric gratings which, however, operate at a single wavelength and occupy a large area. In contrast to gratings and thick plates, the compact size of the microsphere and its capability to support spin-wave excitations make it suitable for applications in nanophotonics, imaging systems, and magnonics.

  2. Sunitinib microspheres based on [PDLLA-PEG-PDLLA]-b-PLLA multi-block copolymers for ocular drug delivery.

    Science.gov (United States)

    Ramazani, F; Hiemstra, C; Steendam, R; Kazazi-Hyseni, F; Van Nostrum, C F; Storm, G; Kiessling, F; Lammers, T; Hennink, W E; Kok, R J

    2015-09-01

    Sunitinib is a multi-targeted receptor tyrosine kinase (RTK) inhibitor that blocks several angiogenesis related pathways. The aim of this study was to develop sunitinib-loaded polymeric microspheres that can be used as intravitreal formulation for the treatment of ocular diseases. A series of novel multi-block copolymers composed of amorphous blocks of poly-(D,L-lactide) (PDLLA) and polyethylene glycol (PEG) and of semi-crystalline poly-(L-lactide) (PLLA) blocks were synthesized. Sunitinib-loaded microspheres were prepared by a single emulsion method using dichloromethane as volatile solvent and DMSO as co-solvent. SEM images showed that the prepared microspheres (∼ 30 μm) were spherical with a non-porous surface. Sunitinib-loaded microspheres were studied for their degradation and in-vitro release behavior. It was found that increasing the percentage of amorphous soft blocks from 10% to 30% accelerated the degradation of the multi-block copolymers. Sunitinib microspheres released their cargo for a period of at least 210 days by a combination of diffusion and polymer erosion. The initial burst (release in 24h) and release rate could be tailored by controlling the PEG-content of the multi-block copolymers. Sunitinib-loaded microspheres suppressed angiogenesis in a chicken chorioallantoic membrane (CAM) assay. These microspheres therefore hold promise for long-term suppression of ocular neovascularization.

  3. Optical microresonator based on hollow sphere with porous wall for chemical sensing.

    Science.gov (United States)

    Wang, Hanzheng; Yuan, Lei; Kim, Cheol-Woon; Han, Qun; Wei, Tao; Lan, Xinwei; Xiao, Hai

    2012-01-01

    A porous-wall hollow glass microsphere (PW-HGM) was investigated as an optical resonator for chemical vapor sensing. A single mode optical fiber taper was used to interrogate the microresonator. Adsorption of chemical molecules into the nanosized pores induced a refractive index change of the thin wall and thus a shift in its resonance spectrum. The PW-HGM resonator had shown higher vapor detection sensitivity in comparison with a solid microsphere under similar test conditions.

  4. Facile synthesis of Co{sub 3}O{sub 4} hierarchical microspheres with improved lithium storage performances

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xiaojuan, E-mail: houxiaojuan@nuc.edu.cn; He, Jian; An, Kun; Mu, Jiliang; Chou, Xiujian; Xue, Chenyang

    2016-10-15

    Highlights: • The Co{sub 3}O{sub 4} microspheres were first fabricated without any surfactant. • The Co{sub 3}O{sub 4} microspheres present excellent electrochemical performances. • The excellent performances result from porous nanosheets assembled architectures. • The microspheres exhibit a high specific capacity of 1000 mA h g at 100 mA g. - Abstract: Porous nanosheets-assembled Co{sub 3}O{sub 4} microspheres have been first successfully fabricated by a facile solvothermal method without any surfactant followed by a relatively low annealing temperature (400 °C) with a higher specific surface area compared to the annealing temperature of 600 °C. The nanosheets-assembled microspheres exhibit a high discharge capacity of 1000 mA h g{sup −1} at a current density of 100 mA g{sup −1} after 50 cycles and 850 mA h g{sup −1} at a current density of 500 mA g{sup −1} after 80 cycles, even at a high current density of 1.6 A g{sup −1} the cycling reversible capacity can still keep 750 mA h g{sup −1}, the representative capacities are relatively higher than most of reports about pure Co{sub 3}O{sub 4}. We attribute the excellent electrochemical performances to the porous nanosheets structure and architectures, which can provide more effective electrode/electrolyte contact area and direct ion transmission path, then lead to faster lithium-ion diffusion, confirmed by EIS measurements. The high specific capacity, excellent cycling and rate performances demonstrate that the porous nanosheets assembled microspheres present promising application in lithium storage.

  5. Balancing mechanical strength with bioactivity in chitosan-calcium phosphate 3D microsphere scaffolds for bone tissue engineering: air- vs. freeze-drying processes.

    Science.gov (United States)

    Nguyen, D T; McCanless, J D; Mecwan, M M; Noblett, A P; Haggard, W O; Smith, R A; Bumgardner, J D

    2013-01-01

    The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres.

  6. Comparative Investigation on Thermal Insulation of Polyurethane Composites Filled with Silica Aerogel and Hollow Silica Microsphere.

    Science.gov (United States)

    Liu, Chunyuan; Kim, Jin Seuk; Kwon, Younghwan

    2016-02-01

    This paper presents a comparative study on thermal conductivity of PU composites containing open-cell nano-porous silica aerogel and closed-cell hollow silica microsphere, respectively. The thermal conductivity of PU composites is measured at 30 degrees C with transient hot bridge method. The insertion of polymer in pores of silica aerogel creates mixed interfaces, increasing the thermal conductivity of resulting composites. The measured thermal conductivity of PU composites filled with hollow silica microspheres is estimated using theoretical models, and is in good agreement with Felske model. It appears that the thermal conductivity of composites decreases with increasing the volume fraction (phi) when hollow silica microsphere (eta = 0.916) is used.

  7. Fabrication and characterization of hydroxyapatite microspheres obtained by ultrasonic atomization method

    Institute of Scientific and Technical Information of China (English)

    WANG Aijuan; LU Yupeng; CHEN Chuanzhong; SUN Ruixue

    2007-01-01

    Two kinds of hydroxyapatite microspheres were prepared using an ultrasonic atomization method. The surface morphology, phase composition, size distribution and spe-cific surface area were determined by field emission scanning electron microscopy, transmission electron microscopy,X-ray diffractometry and laser diffraction particle size analy-sis, respectively. The results indicate that the hydroxyapatite microspheres are composed of nanosized crystals and have porous surface morphology. The specific surface areas are different before sintering, and have a slight difference after sintering. The size distribution of the microspheres added with Lopon 885 is narrow and the average size is smaller than those fabricated without the addition of Lopon 885. Besides,the impurity phase, tetracalcium phosphate, appeared during ultrasonic atomizing procedure, and can be completely removed after sintering at 650℃ for 1 h.

  8. PREPARATION AND IN-VITRO EVALUATION OF BACLOFEN LOADED MICROSPHERES

    Directory of Open Access Journals (Sweden)

    Polepalle Madhulatha

    2012-09-01

    Full Text Available The present study was aimed to prepare Baclofen microspheres for sustained release using various polymers such as ethyl cellulose (hydrophobic, hydroxy propyl methyl cellulose (hydrophilic by employing solvent evaporation technique. Drug and excipients compatibility was studied by Fourier Transform Infrared Spectroscopy and no incompatibility was observed. The obtained microspheres were evaluated for the percent drug content, entrapment efficiency and in-vitro dissolution studies. The entrapment efficiency of the obtained formulations was in between 66-88% and in-vitro release of F7 formulation showed 93% in 24 hrs. Scanning Electron Microscopy, Differential Scanning Calorimetry and X-Ray Diffraction studies were performed for F7 formulation. From the results Scanning Electron Microscopy of reveals that microspheres was found in spherical and porous nature. X-Ray Diffraction studies results showed baclofen was in amorphous form which was further confirmed by Differential Scanning Calorimetry. The curve fitting data revealed that the release of obtained formulations follows mixed order kinetics with non‐fickian type of drug release (anomalous.

  9. Ultrasonic atomization for spray drying: a versatile technique for the preparation of protein loaded biodegradable microspheres.

    Science.gov (United States)

    Bittner, B; Kissel, T

    1999-01-01

    Bovine serum albumin (BDA) loaded microspheres with a spherical shape and smooth surface structure were successfully prepared from poly(lactide-co-glycolide) using an ultrasonic nozzle installed in a Niro laboratory spray dryer. Process and formulation parameters were investigated with respect to their influence on microsphere characteristics, such as particle size, loading capacity, and release properties. Preparation of microspheres in yields of more than 50% was achieved using an ultrasonic atomizer connected to a stream of carrier air. Microsphere characteristics could be modified by changing several technological parameters. An increased polymer concentration of the feed generated larger particles with a significantly reduced initial release of the protein. Moreover, microspheres with a smooth surface structure were obtained from the organic polymer solution with the highest viscosity. Microparticles with a low BSA loading showed a large central cavity surrounded by a thin polymer layer in scanning electron microspheres. A high protein loading led to an enlargement of the shell layer, or even to dense particles without any cavities. A continuous in vitro release pattern of BSA was obtained from the particles with low protein loading. Glass transition temperatures (Tg) of the microspheres before and after lyophilization did not differ from those of the BSA loaded particles prepared by spray drying with a rotary atomizer. Analysis of the polymer by gel permeation chromatography indicated that ultrasonication had no effect on polymer molecular weight. Molecular weight and polydispersity of the pure polymer, placebo microspheres prepared by spray drying, and placebo microspheres prepared using the ultrasonic nozzle were in the same range. In conclusion, ultrasonic atomization represents a versatile and reliable technique for the production of protein loaded biodegradable microspheres without inducing a degradation of the polymer matrix. Particle characteristics

  10. Microspheres and their methods of preparation

    Science.gov (United States)

    Bose, Anima B; Yang, Junbing

    2015-03-24

    Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

  11. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  12. Large-area one-step assembly of three-dimensional porous metal micro/nanocages by ethanol-assisted femtosecond laser irradiation for enhanced antireflection and hydrophobicity.

    Science.gov (United States)

    Li, Guoqiang; Li, Jiawen; Zhang, Chenchu; Hu, Yanlei; Li, Xiaohong; Chu, Jiaru; Huang, Wenhao; Wu, Dong

    2015-01-14

    The capability to realize 2D-3D controllable metallic micro/nanostructures is of key importance for various fields such as plasmonics, electronics, bioscience, and chemistry due to unique properties such as electromagnetic field enhancement, catalysis, photoemission, and conductivity. However, most of the present techniques are limited to low-dimension (1D-2D), small area, or single function. Here we report the assembly of self-organized three-dimensional (3D) porous metal micro/nanocages arrays on nickel surface by ethanol-assisted femtosecond laser irradiation. The underlying formation mechanism was investigated by a series of femtosecond laser irradiation under exposure time from 5 to 30 ms. We also demonstrate the ability to control the size of micro/nanocage arrays from 0.8 to 2 μm by different laser pulse energy. This method features rapidness (∼10 min), simplicity (one-step process), and ease of large-area (4 cm(2) or more) fabrication. The 3D cagelike micro/nanostructures exhibit not only improved antireflection from 80% to 7% but also enhanced hydrophobicity from 98.5° to 142° without surface modification. This simple technique for 3D large-area controllable metal microstructures will find great potential applications in optoelectronics, physics, and chemistry.

  13. The mechanism of protein release from triglyceride microspheres.

    Science.gov (United States)

    Zaky, A; Elbakry, A; Ehmer, A; Breunig, M; Goepferich, A

    2010-10-15

    The purpose of this study was to reveal factors that have an impact on the protein release kinetics from triglyceride microspheres prepared by spray congealing. We investigated the effect of protein particle size, morphology and distribution on protein release from microspheres by confocal laser scanning microscopy (CLSM)(.) The microspheres were loaded with three types of model particles made of FITC-labeled bovine serum albumin: freeze dried protein, spherical particles obtained by precipitation in the presence of PEG and micronized material. Investigation by light microscopy and laser light diffraction revealed that the freeze dried material consisted mainly of app. 29 μm elongated shaped particles. The precipitated BSA consisted mainly of 9.0 μm diameter spherically shaped particles while the micronized protein prepared by jet milling consisted of 4.9 μm sized rounded particles of high uniformity. Microspheres were embedded into a cold-curing resin and cut with a microtome. Subsequent investigation by CLSM revealed major differences of distribution of the polydisperse protein particles inside the microsphere sections depending on the type of BSA that was used. Particles of micronized and precipitated protein were distributed almost throughout the microsphere cross section. The protein distribution had a marked impact on the release kinetics in phosphate buffer. Large protein particles led to a considerably faster release than small ones. By staining the release medium we demonstrated that in all three cases there was a strong correlation between protein release and buffer intrusion. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Large Deformation Dynamic Three-Dimensional Coupled Finite Element Analysis of Soft Biological Tissues Treated as Biphasic Porous Media

    Science.gov (United States)

    2014-11-01

    2006; White and Borja, 2008; Sun, Ostien, and Salinger , 2013) Q8P8 hexahedral element is also implemented within the coupled dynamics framework, and...but based on our implementation, it was ineffective for our particular applications of soft tissues at finite strain. Sun, Ostien, and Salinger ...large deformation. Int. J. Numer. Methods Engrg., vol. 32, pp. 1411–1439. Sun, W.-C.; Ostien, J.; Salinger , A. (2013): A stabilized assumed

  15. Advances in Microsphere Insulation Systems

    Science.gov (United States)

    Allen, M. S.; Baumgartner, R. G.; Fesmire, J. E.; Augustynowicz, S. D.

    2004-06-01

    Microsphere insulation, typically consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. Microspheres provide robust, low-maintenance insulation systems for cryogenic transfer lines and dewars. They also do not suffer from compaction problems typical of perlite that result in the necessity to reinsulate dewars because of degraded thermal performance and potential damage to its support system. Since microspheres are load bearing, autonomous insulation panels enveloped with lightweight vacuum-barrier materials can be created. Comprehensive testing performed at the Cryogenics Test Laboratory located at the NASA Kennedy Space Center demonstrated competitive thermal performance with other bulk materials. Test conditions were representative of actual-use conditions and included cold vacuum pressure ranging from high vacuum to no vacuum and compression loads from 0 to 20 psi. While microspheres have been recognized as a legitimate insulation material for decades, actual implementation has not been pursued. Innovative microsphere insulation system configurations and applications are evaluated.

  16. A novel route for synthesis and growth formation of metal oxides microspheres: Insights from V{sub 2}O{sub 3} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yifu, E-mail: yfzhang@dlut.edu.cn [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Huang, Chi [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Meng, Changgong; Hu, Tao [School of Chemistry, Dalian University of Technology, Dalian 116024 (China)

    2016-07-01

    Highly polydisperse V{sub 2}O{sub 3} solid microspheres with large specific surface area were successfully synthesized via a facile hydrothermal decomposition of VOC{sub 2}O{sub 4} solution. The morphology and composition were characterized by scanning electron microscopy (SEM), Energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). V{sub 2}O{sub 3} microspheres display an obvious Mott phase transition at −128.5 °C (cooling curve) and −114.5 °C (heating curve). Some parameters including the reaction temperature, concentration of VOC{sub 2}O{sub 4}, reaction time, surfactant, H{sub 2}C{sub 2}O{sub 4} and precursor were briefly discussed to reveal the formation of V{sub 2}O{sub 3} microspheres. It was found that the precursor is crucial for the fabrication of microsphere. A self-assembly growth mechanism was suggested to explain the growth process of microspheres and the autogenic CO and CO{sub 2} gas served as the soft templates. Furthermore, this route was developed to synthesize different metal oxides microspheres, and it was found that AlO(OH), Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}, Co{sub 3}O{sub 4}, Cr{sub 2}O{sub 3}, MoO{sub 2} and WO{sub 3} microspheres were obtained. All the results showed this process was successfully explored as a methodology to synthesize different metal oxides microspheres using the gas as the templates by this facile hydrothermal route. - Highlights: • Highly uniform V{sub 2}O{sub 3} solid microspheres were synthesized. • V{sub 2}O{sub 3} microspheres display an obvious Mott phase transition. • The autogenic CO and CO{sub 2} gas served as the soft templates for designed synthesis. • AlO(OH), Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}, Co{sub 3}O{sub 4}, Cr{sub 2}O{sub 3}, MoO{sub 2} and WO{sub 3} microspheres were obtained. • A methodology to synthesize different metal oxides microspheres was developed.

  17. Encapsulation of Liposomes within pH Responsive Microspheres for Oral Colonic Drug Delivery

    Directory of Open Access Journals (Sweden)

    M. J. Barea

    2012-01-01

    Full Text Available A novel liposome-in-microsphere (LIM formulation has been created comprising drug-loaded liposomes within pH responsive Eudragit S100 microspheres. The liposomes contained the model drug 5-ASA and were coated with chitosan in order to protect them during encapsulation within the microspheres and to improve site-specific release characteristics. In vitro drug release studies showed that LIMs prevented drug release within simulated stomach and small intestine conditions with subsequent drug release occurring in large intestine conditions. The formulation therefore has potential for oral colonic drug delivery.

  18. Encapsulation of azithromycin into polymeric microspheres by reduced pressure-solvent evaporation method

    DEFF Research Database (Denmark)

    Li, Xiujuan; Chang, Si; Du, Guangsheng

    2012-01-01

    Azithromycin loaded microspheres with blends of poly-l-lactide and ploy-D,L-lactide-co-glycolide as matrices were prepared by the atmosphere-solvent evaporation (ASE) and reduced pressure-solvent evaporation (RSE) method. Both the X-ray diffraction spectra and DSC thermographs demonstrated...... that poly-L-lactide existed in a crystalline form in the ASE microspheres, while an amorphous form was present in the RSE formulations. Besides, solvent removal at atmosphere gave microspheres of porous and rough surfaces, but smooth surfaces appeared in the RSE microspheres. The incorporation efficiency...... as well as the burst release (cumulative release in the first 24h) in the ASE formulations was 39.94 ± 1.18% and 23.96 ± 2.01% respectively, yet the encapsulation efficiency of the microspheres fabricated under 385 mmHg was high up to 57.19 ± 3.81% and the burst release was 4.12 ± 0.15%. The in vitro drug...

  19. Sustained release donepezil loaded PLGA microspheres for injection: Preparation, in vitro and in vivo study

    Directory of Open Access Journals (Sweden)

    Wenjia Guo

    2015-10-01

    Full Text Available The purpose of this study was to develop a PLGA microspheres-based donepezil (DP formulation which was expected to sustain release of DP for one week with high encapsulation efficiency (EE. DP derived from donepezil hydrochloride was encapsulated in PLGA microspheres by the O/W emulsion-solvent evaporation method. The optimized formulation which avoided the crushing of microspheres during the preparation process was characterized in terms of particle size, morphology, drug loading and EE, physical state of DP in the matrix and in vitro and in vivo release behavior. DP microspheres were prepared successfully with average diameter of 30 µm, drug loading of 15.92 ± 0.31% and EE up to 78.79 ± 2.56%. Scanning electron microscope image showed it has integrated spherical shape with no drug crystal and porous on its surface. Differential scanning calorimetry and X-ray diffraction results suggested DP was in amorphous state or molecularly dispersed in microspheres. The Tg of PLGA was increased with the addition of DP. The release profile in vitro was characterized with slow but continuous release that lasted for about one week and fitted well with first-order model, which suggested the diffusion governing release mechanism. After single-dose administration of DP microspheres via subcutaneous injection in rats, the plasma concentration of DP reached peak concentration at 0.50 d, and then declined gradually, but was still detectable at 15 d. A good correlation between in vitro and in vivo data was obtained. The results suggest the potential use of DP microspheres for treatment of Alzheimer's disease over long periods.

  20. Preparation and characterization of gelatin–hydroxyapatite composite microspheres for hard tissue repair

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Shao Ching [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan (China); Department of Minimally Invasive Skull Neurosurgery, Neurological Institute, Taichung Veterans General Hospital, 1650 Taiwan Boulevard, Sect. 4, Taichung, Taiwan (China); Department of Neurosurgery, ChangHua Hospital, Ministry of Health and Welfare, 80 Chung Cheng Road, Sect. 2 Chiu Kuan Village, Changhua 500, Taiwan (China); Wang, Ming-Jia; Pai, Nai-Su [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan (China); Yen, Shiow-Kang, E-mail: skyen@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan (China)

    2015-12-01

    Gelatin–hydroxyapatite composite microspheres composed of 21% gelatin (G) and 79% hydroxyapatite (HA) with uniform morphology and controllable size were synthesized from a mixed solution of Ca(NO{sub 3}){sub 2}, NH{sub 4}H{sub 2}PO{sub 4} and gelatin by a wet-chemical method. Material analyses such as X-ray diffraction (XRD), scanning/transmission electron microscopy examination (SEM/TEM) and inductively coupled plasma-mass spectroscopy (ICP-MS) were used to characterize G–HA microspheres by analyzing their crystalline phase, microstructure, morphology and composition. HA crystals precipitate along G fibers to form nano-rods with diameters of 6–10 nm and tangle into porous microspheres after blending. The cell culture indicates that G–HA composite microspheres without any toxicity could enhance the proliferation and differentiation of osteoblast-like cells. In a rat calvarial defect model, G–HA bioactive scaffolds were compared with fibrin glue (F) and Osteoset® Bone Graft Substitute (OS) for their capacity of regenerating bone. Four weeks post-implantation, new bone, mineralization, and expanded blood vessel area were found in G–HA scaffolds, indicating greater osteoconductivity and bioactivity than F and OS. - Highlights: • G–HA composite microspheres were prepared by hydroxyapatite and gelatin. • In vitro tests indicated that the G–HA microspheres were biocompatible and bioactive. • In in vitro tests, G–HA microspheres could be applied in hard tissue engineering. • G–HA had healed the bone defect and provides a high proportion of surface area to open space.

  1. Polarization Dependent Whispering Gallery Modes in Microspheres

    Science.gov (United States)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  2. Enhanced Oil Recovery Using Micron-Size Polyacrylamide Elastic Microspheres (MPEMs): Underlying Mechanisms and Displacement Experiments

    KAUST Repository

    Yao, Chuanjin

    2015-10-12

    Micron-size polyacrylamide elastic microsphere (MPEM) is a newly developed profile control and oil displacement agent for enhanced oil recovery in heterogeneous reservoirs. In this study, laboratory experiments were performed to characterize the viscoelastic properties of MPEMs in brine water. A transparent sandpack micromodel was used to observe the microscopic flow and displacement mechanisms, and parallel-sandpack models were used to investigate the profile control and oil displacement performance using MPEMs in heterogeneous reservoirs. The results indicate that MPEMs almost do not increase the viscosity of injection water and can be conveniently injected using the original water injection pipelines. The microscopic profile control and oil displacement mechanisms of MPEMs in porous media mainly behave as selective-plugging in large pores, fluid diversion after MPEMs plugging, oil drainage caused by MPEMs breakthrough, and the mechanism of oil droplets converging into oil flow. MPEMs have a high plugging strength, which can tolerate a long-term water flushing. MPEMs can selectively enter and plug the large pores and pore-throats in high permeability sandpack, but almost do not damage the low permeability sandpack. MPEMs can effectively divert the water flow from the high permeability sandpack to the low permeability sandpack and improve the sweep efficiency of low permeability sandpack and low permeability area in the high permeability sandpack. The results also confirm the dynamic process of profile control and oil displacement using MPEMs in heterogeneous reservoirs.

  3. Encapsulation and characterization of controlled release flurbiprofen loaded microspheres using beeswax as an encapsulating agent.

    Science.gov (United States)

    Ranjha, Nazar M; Khan, Hafeezullah; Naseem, Shahzad

    2010-05-01

    The aim of the present study was to extend the use of flurbiprofen in clinical settings by avoiding its harmful gastric effects. For this purpose, we designed the controlled release solid lipid flurbiprofen microspheres (SLFM) by emulsion congealing technique. Drug was entrapped into gastro resistant biodegradable beeswax microspheres which were prepared at different drug/beeswax ratios 1:1, 1:2 and 1:3 using gelatin and tween 20 as emulsifying agents. The effect of emulsifiers and the effect drug/beeswax ratios were studied on hydration rate, encapsulating efficiency, micromeritic properties, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (X-RD) analysis and in vitro drug release at pH 1.2 for 2 h and at pH 6.8 for 10 h. SEM revealed that microspheres made with tween 20 were smooth while microspheres made with gelatin showed porous morphology, however, they were all spherical in nature. The practical yield (recovery) showed a dependence on drug-beeswax ratio and it was variable from 53 to 84%. High loading encapsulating efficiency of flurbiprofen from 8 to 94% was achieved. FTIR and DSC analysis confirmed the absence of any drug polymer interaction indicating drug stability during microencapsulation. X-RD of pure flurbiprofen shows sharp peaks, which decreases on encapsulation, indicating decrease in the crystallinity of drug in microspheres. The micromeritic studies confirmed the presence of excellent and good flow properties of microspheres. Entrapment efficiency, morphology, practical yield, hydration rate, flow properties demonstrated their dependence on the HLB value of emulsifiers and emulsifiers with higher HLB were found more appropriate for effective microencapsulation of flurbiprofen. The release kinetics followed zero order mechanism of drug release at pH 6.8. Release pattern depends on the morphology of flurbiprofen microspheres and amount of beeswax used in

  4. Metal-Free Counter Electrode for Efficient Dye-Sensitized Solar Cells through High Surface Area and Large Porous Carbon

    Directory of Open Access Journals (Sweden)

    Pavuluri Srinivasu

    2011-01-01

    Full Text Available Highly efficient, large mesoporous carbon is fabricated as a metal-free counter electrode for dye-sensitized solar cells. The mesoporous carbon shows very high energy conversion efficiency of 7.1% compared with activated carbon. The mesoporous carbon is prepared and characterized by nitrogen adsorption, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The nitrogen adsorption data reveals that the material possesses BET specific surface area ca.1300 m2/g and pore diameter 4.4 nm. Hexagonal rod-like morphology and ordered pore structure of mesoporous carbon are confirmed by electron microscopy data. The better performance of this carbon material is greatly benefited from its ordered interconnected mesoporous structure and high surface area.

  5. Formulation and evaluation of controlled release floating microspheres of tolperisone hydrochloride

    Directory of Open Access Journals (Sweden)

    Pooja Jani

    2012-01-01

    Full Text Available Main aim of this study was to develop controlled release (CR floating multiparticulate drug delivery system of tolperisone hydrochloride. Microspheres were prepared by nonaqueous solvent evaporation technique consisting of porous calcium silicate (Florite or FLR as porous carrier, tolperisone hydrochloride (API, Ethyl cellulose (EC, and HPMC 15 cPs as rate controlling polymers. 2 3 full factorial design was applied for optimization of formulation. The effect of various formulation and process variables on the particle morphology, micromeritic properties, in vitro floating behavior, entrapment efficiency, and in vitro drug release were studied. The size of microspheres was varied from 300 to 500 μm. The microspheres were found to be highly porous and regular in shape. All the formulations showed excellent flow properties. The percentage entrapment efficiency of all batches was greater than 80%. The percentage buoyancy varied from 85% to 98% at the end of 12 h. The release rate was determined in simulated gastric fluids. The formulation demonstrated favorable in vitro floating and release characteristics. Different kinetic models were applied to study the release mechanism. All formulations followed Higuchi model, which indicates the diffusion control release of water soluble drug from polymer matrix. Multiple regression analysis was applied for study of the effect of independent variables on the dependent variables.

  6. Microsphere Super-resolution Imaging

    CERN Document Server

    Wang, Zengbo

    2015-01-01

    Recently, it was discovered that microsphere can generate super-resolution focusing beyond diffraction limit. This has led to the development of an exciting super-resolution imaging technique -microsphere nanoscopy- that features a record resolution of 50 nm under white lights. Different samples have been directly imaged in high resolution and real time without labelling, including both non-biological (nano devices, structures and materials) and biological (subcellular details, viruses) samples. This chapter reviews the technique, which covers its background, fundamentals, experiments, mechanisms as well as the future outlook.

  7. Inhalable oridonin-loaded poly(lactic-co-glycolic)acid large porous microparticles for in situ treatment of primary non-small cell lung cancer.

    Science.gov (United States)

    Zhu, Lifei; Li, Miao; Liu, Xiaoyan; Du, Lina; Jin, Yiguang

    2017-01-01

    Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. Traditional chemotherapy for this disease leads to serious side effects. Here we prepared an inhalable oridonin-loaded poly(lactic-co-glycolic)acid (PLGA) large porous microparticle (LPMP) for in situ treatment of NSCLC with the emulsion/solvent evaporation/freeze-drying method. The LPMPs were smooth spheres with many internal pores. Despite a geometric diameter of ~10 µm, the aerodynamic diameter of the spheres was only 2.72 µm, leading to highly efficient lung deposition. In vitro studies showed that most of oridonin was released after 1 h, whereas the alveolar macrophage uptake of LPMPs occurred after 8 h, so that most of oridonin would enter the surroundings without undergoing phagocytosis. Rat primary NSCLC models were built and administered with saline, oridonin powder, gemcitabine, and oridonin-loaded LPMPs via airway, respectively. The LPMPs showed strong anticancer effects. Oridonin showed strong angiogenesis inhibition and apoptosis. Relevant mechanisms are thought to include oridonin-induced mitochondrial dysfunction accompanied by low mitochondrial membrane potentials, downregulation of BCL-2 expressions, upregulation of expressions of BAX, caspase-3 and caspase-9. The oridonin-loaded PLGA LPMPs showed high anti-NSCLC effects after pulmonary delivery. In conclusion, LPMPs are promising dry powder inhalations for in situ treatment of lung cancer.

  8. Inhalable oridonin-loaded poly(lactic-co-glycolicacid large porous microparticles for in situ treatment of primary non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Lifei Zhu

    2017-01-01

    Full Text Available Non-small cell lung cancer (NSCLC accounts for about 85% of all lung cancers. Traditional chemotherapy for this disease leads to serious side effects. Here we prepared an inhalable oridonin-loaded poly(lactic-co-glycolicacid (PLGA large porous microparticle (LPMP for in situ treatment of NSCLC with the emulsion/solvent evaporation/freeze-drying method. The LPMPs were smooth spheres with many internal pores. Despite a geometric diameter of ~10 µm, the aerodynamic diameter of the spheres was only 2.72 µm, leading to highly efficient lung deposition. In vitro studies showed that most of oridonin was released after 1 h, whereas the alveolar macrophage uptake of LPMPs occurred after 8 h, so that most of oridonin would enter the surroundings without undergoing phagocytosis. Rat primary NSCLC models were built and administered with saline, oridonin powder, gemcitabine, and oridonin-loaded LPMPs via airway, respectively. The LPMPs showed strong anticancer effects. Oridonin showed strong angiogenesis inhibition and apoptosis. Relevant mechanisms are thought to include oridonin-induced mitochondrial dysfunction accompanied by low mitochondrial membrane potentials, downregulation of BCL-2 expressions, upregulation of expressions of BAX, caspase-3 and caspase-9. The oridonin-loaded PLGA LPMPs showed high anti-NSCLC effects after pulmonary delivery. In conclusion, LPMPs are promising dry powder inhalations for in situ treatment of lung cancer.

  9. Efficient Construction of Well-Defined Multicompartment Porous Systems in a Modular and Chemically Orthogonal Fashion.

    Science.gov (United States)

    Gao, Ning; Tian, Tian; Cui, Jiecheng; Zhang, Wanlin; Yin, Xianpeng; Wang, Shiqiang; Ji, Jingwei; Li, Guangtao

    2017-03-27

    A microfluidic assembly approach was developed for efficiently producing hydrogel spheres with reactive multidomains that can be employed as an advantageous platform to create spherical porous networks in a facile manner with well-defined multicompartments and spatiotemporally controlled functions. This strategy allows for not only large scale fabrication of various robust hydrogel microspheres with controlled size and porosity, but also the domains embedded in hydrogel network could be introduced in a modular manner. Additionally, the number of different domains and their ratio could be widely variable on demand. More importantly, the reactive groups distributed in individual domains could be used as anchor sites to further incorporate functional units in an orthogonal fashion, leading to well-defined multicompartment systems. The strategy provides a new and efficient route to construct well-defined functional multicompartment systems with great flexibility and extendibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Large Particle Titanate Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    This research project was aimed at developing a synthesis technique for producing large particle size monosodium titanate (MST) to benefit high level waste (HLW) processing at the Savannah River Site (SRS). Two applications were targeted, first increasing the size of the powdered MST used in batch contact processing to improve the filtration performance of the material, and second preparing a form of MST suitable for deployment in a column configuration. Increasing the particle size should lead to improvements in filtration flux, and decreased frequency of filter cleaning leading to improved throughput. Deployment of MST in a column configuration would allow for movement from a batch process to a more continuous process. Modifications to the typical MST synthesis led to an increase in the average particle size. Filtration testing on dead-end filters showed improved filtration rates with the larger particle material; however, no improvement in filtration rate was realized on a crossflow filter. In order to produce materials suitable for column deployment several approaches were examined. First, attempts were made to coat zirconium oxide microspheres (196 µm) with a layer of MST. This proved largely unsuccessful. An alternate approach was then taken synthesizing a porous monolith of MST which could be used as a column. Several parameters were tested, and conditions were found that were able to produce a continuous structure versus an agglomeration of particles. This monolith material showed Sr uptake comparable to that of previously evaluated samples of engineered MST in batch contact testing.

  11. The Therapeutic Benefit of Allopurinol in the Treatment of Foreign Body Granulomas Caused by Polymethylmethacrylate Microspheres

    Directory of Open Access Journals (Sweden)

    Luisa Kelmer Côrtes de Barros Silveira

    2012-01-01

    Full Text Available Injectable polymethylmethacrylate (PMMA microspheres are nonbiodegradable and too large for macrophage phagocytosis. There are several complications possible to happen, like chronic nonspecific inflammatory reactions, lip stiffness, infection, and granulomas. The occurrence of granulomas can lead to a not aesthetic result, making some extreme changes in the patient’s life. The objective of this case report is to describe the successful treatment of foreign body granulomas caused by polymethylmethacrylate microspheres using allopurinol, an innovative therapy for this condition.

  12. Use of boiled hexamethylenetetramine and urea to increase the porosity of cerium dioxide microspheres formed in the internal gelation process

    Science.gov (United States)

    Hunt, R. D.; Collins, J. L.; Cowell, B. S.

    2017-08-01

    Cerium dioxide (CeO2) is a commonly used simulant for plutonium dioxide and for plutonium (Pu) in uranium (U) and Pu oxide [(U, Pu)O2] mixtures used in nuclear fuel development. This effort developed CeO2 microspheres with a various porosities and diameters. The internal gelation technique has only been used to produce CeO2 microspheres with limited initial porosity. Previous studies have shown that the crystallite size and porosity of mixed U and thorium oxide microspheres and the (U, Pu)O2 microspheres from the internal gelation process increased when an equal molar solution of hexamethylenetetramine (HMTA) and urea is gently boiled for 1 h prior to its use in the gelation process. In this study with cerium, the combination of ammonium cerium nitrate and 1-h boiled HMTA-urea failed to produce a stable feed broth. However, when the 1-h heated HMTA-urea was combined with unheated HMTA-urea in 1-3 vol ratio or the boiling time of the HMTA-urea was reduced to 15-20 min, a stable solution of HMTA, urea, and Ce was formed at 273 K. This new Ce solution produced very porous CeO2 microspheres, which are suitable simulants for uranium microspheres.

  13. Encapsulation of plant oils in porous starch microspheres

    Science.gov (United States)

    Natural plant products such as essential oils have gained interest for use in pest control in place of synthetic pesticides because of their low environmental impact. Essential oils can be effective in controlling parasitic mites that infest honeybee colonies but effective encapsulants are needed to...

  14. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  15. A microfluidic approach to assembling ordered microsphere arrays

    Science.gov (United States)

    Xu, W.; Sur, K.; Zeng, H.; Feinerman, A.; Kelso, D.; Ketterson, J. B.

    2008-07-01

    Hydrodynamic flow through an array of channels has been utilized to assemble microspheres on a flat surface. The channels, about 6 µm in lateral size, were etched through a 60 µm thick silicon wafer using deep reactive ion etching (DRIE). Droplets containing 6-8 µm fluorescent polystyrene microspheres were placed on the top side of the horizontally-oriented silicon wafer, while the bottom side was connected to a syringe that draws the fluid through the channels. In this way the microspheres are guided and secured at the inlets of the channels, and remain in place when the suction ceases. This technique, which combines favorable features such as high throughput, high resolution rate and reusability, can be a powerful platform for a new generation of protein microarrays. Antigens can be bound to the microspheres as 'targets', which can then be exposed to different fluorescence-tagged antibodies so that their binding can be confirmed. This system can also be used to study the functional roles of gene fragments and their relations to human diseases. The high throughput feature will make it possible to screen a large number of DNA fragments and identify the genetic basis of various diseases effectively.

  16. Polymer microspheres with structured surfaces

    NARCIS (Netherlands)

    Wagdare, N.A.; Baggerman, J.; Marcelis, A.T.M.; Boom, R.M.; Rijn, van C.J.M.

    2011-01-01

    Microspheres from polymethyl methacrylate (PMMA) and Eudragit FS 30D (a commercial copolymer of poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3:1) were prepared using microsieve emulsification. A mixture of these polymers in dichloromethane (DCM) was dispersed into water, leadin

  17. Development of Risperidone PLGA Microspheres

    Directory of Open Access Journals (Sweden)

    Susan D’Souza

    2014-01-01

    Full Text Available The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25 were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug.

  18. Optical trapping of coated microspheres

    NARCIS (Netherlands)

    Bormuth, V.; Jannasch, A.; Ander, M.; van Kats, C.M.; van Blaaderen, A.; Howard, J.; Schäffer, E.

    2008-01-01

    In an optical trap, micron-sized dielectric particles are held by a tightly focused laser beam. The optical force on the particle is composed of an attractive gradient force and a destabilizing scattering force. We hypothesized that using anti-reflection-coated microspheres would reduce scattering a

  19. Solvothermal synthesis of monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres and their application as microwave absorber

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tingting [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Sun, Genban, E-mail: gbsun@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Ma, Shulan; Yang, Xiaojing [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Hu, Changwen [Key Laboratory of Cluster Science, Ministry of Education of China and Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (China)

    2012-03-15

    Graphical abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres with shell structure were synthesized via a combined solvothermal method and calcination route. The radar-wave absorbability of the purple sample calcined at 900 Degree-Sign C was strongest at the frequency of about 8.5 GHz. Highlights: Black-Right-Pointing-Pointer In this study we synthesized monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres as microwave absorber. Black-Right-Pointing-Pointer The relationship between microstructures and the electromagnetic properties was indicated. Black-Right-Pointing-Pointer The radar-wave absorbability of the sample was included. -- Abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with a diameter of 40 {mu}m were achieved via a combining solvothermal and calcination route. The crystallinity of the calcined microspheres with shell structure was improved, while the monodisperse property and morphologies remained. The possible formation mechanism of the porous CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with nanoshell was proposed. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) technologies, thermal analysis (TG and DSC), nitrogen adsorption-desorption isotherms and network analyzer. The sample calcined at 900 Degree-Sign C shows a strongest absorbability in the radar-wave absorbability test.

  20. Mesoporous Titania Microspheres with Highly Tunable Pores as an Anode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Fischer, Michael G; Hua, Xiao; Wilts, Bodo D; Gunkel, Ilja; Bennett, Thomas M; Steiner, Ullrich

    2017-07-12

    Mesoporous titania microspheres (MTMs) have been employed in many applications, including (photo)catalysis as well as energy conversion and storage. Their morphology offers a hierarchical structural design motif that lends itself to being incorporated into established large-scale fabrication processes. Despite the fact that device performance hinges on the precise morphological characteristics of these materials, control over the detailed mesopore structure and the tunability of the pore size remains a challenge. Especially the accessibility of a wide range of mesopore sizes by the same synthesis method is desirable, as this would allow for a comparative study of the relationship between structural features and performance. Here, we report a method that combines sol-gel chemistry with polymer micro- and macrophase separation to synthesize porous titania spheres with diameters in the micrometer range. The as-prepared MTMs exhibit well-defined, accessible porosities with mesopore sizes adjustable by the choice of the polymers. When applied as an anode material in lithium ion batteries (LIBs), the MTMs demonstrate excellent performance. The influence of the pore size and an in situ carbon coating on charge transport and storage is examined, providing important insights for the optimization of structured titania anodes in LIBs. Our synthesis strategy presents a facile one-pot approach that can be applied to different structure-directing agents and inorganic materials, thus further extending its scope of application.

  1. Controlled release of dexamethasone from porous PLGA scaffolds under cyclic loading

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Poly(L-lactide)-b-poly(ethylene glycol)(PLLA-PEG) microspheres containing dexamethasone(Dex) have been fabricated using a spray-drying technique.Porous poly(lactic-co-glycolic acid)(PLGA) scaffolds were prepared using a method combining thermally induced phase separation and porogen leaching.A post-seeding technique was used to immobilize Dex-containing PLLA-PEG microspheres on porous PLGA scaffolds,and drug-containing microspheres-scaffolds(MS-S) were obtained.Simple Dex-containing scaffolds(D-S) were also made as the control by directly dissolving Dex in the PLGA solution during scaffold fabrication.The morphologies of microspheres and scaffolds were studied by scanning electron microscopy.Drug release profiles of both MS-S and D-S were determined under cyclic loading and shaking water bath,respectively.The cumulative release of Dex was measured using an ultraviolet visible spectrophotometer.The results show that the incorporation of Dex and microspheres had little effect on the overall morphology of the porous PLGA scaffolds.Cyclic loading significantly accelerated the release of Dex from the drug-containing scaffolds.Compared with D-S,MS-S reduced the drug release rate.The controlled drug delivery of tissue engineering scaffolds under cyclic loading is a key factor to mimic the in vivo mechanical environments and achieve optical clinical efficacy.

  2. Tuning the optical forces on- and off-resonance in microspherical photonics

    CERN Document Server

    Li, Yangcheng; Jofre, Ana; Astratov, Vasily N

    2015-01-01

    Light pressure effect has been discovered long ago and has been used as an optical method to manipulate microand nanoparticles. It is usually considered as a nonresonant effect determined by the transfer of the momentum of light. However, recently we have observed that large polystyrene microspheres of 15-20 {\\mu}m diameters supporting high quality whispering gallery resonances can be optically propelled in water at an extraordinary high velocity along tapered fibers under resonant conditions. In this work we compare on- and off-resonant optical forces in microspherical photonics by controlling the detuning between the laser emission line and whispering gallery resonances. Our approach involves manipulation with microspheres using conventional optical tweezers and their advanced spectroscopic characterization in fiber-integrated setups. We demonstrate dramatic difference in the optical forces exerted on microspheres in the on-resonant and off-resonant cases. This method can be used to study spectral propertie...

  3. Synthesis and electrochemical properties of {alpha}-MnO{sub 2} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hongen [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhengzhou Research Institute of CHALCO, Zhengzhou Research Institute of Light Metals, Zhengzhou 450041 (China); Qian Dong [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)], E-mail: qiandong6@yahoo.com.cn

    2008-06-15

    We report the synthesis of {alpha}-MnO{sub 2} microspheres by a low-temperature hydrothermal method involving no templates or catalysts. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrum (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), and Brunauer-Emmett-Teller (BET). The results show that the as-synthesized products are mainly composed of large quantities of {alpha}-MnO{sub 2} microspheres having a sea-urchin shape and a few microspheres constructed of small nanorods. Electrochemical characterization indicates that the resulting {alpha}-MnO{sub 2} microspheres display promising discharge properties than the commercial electrolytic manganese dioxides (EMD) when used as cathodes in alkaline Zn-MnO{sub 2} batteries.

  4. Versatile microsphere attachment of GFP-labeled motors and other tagged proteins with preserved functionality

    Directory of Open Access Journals (Sweden)

    Michael Bugiel

    2015-11-01

    Full Text Available Microspheres are often used as handles for protein purification or force spectroscopy. For example, optical tweezers apply forces on trapped particles to which motor proteins are attached. However, even though many attachment strategies exist, procedures are often limited to a particular biomolecule and prone to non-specific protein or surface attachment. Such interactions may lead to loss of protein functionality or microsphere clustering. Here, we describe a versatile coupling procedure for GFP-tagged proteins via a polyethylene glycol linker preserving the functionality of the coupled proteins. The procedure combines well-established protocols, is highly reproducible, reliable, and can be used for a large variety of proteins. The coupling is efficient and can be tuned to the desired microsphere-to-protein ratio. Moreover, microspheres hardly cluster or adhere to surfaces. Furthermore, the procedure can be adapted to different tags providing flexibility and a promising attachment strategy for any tagged protein.

  5. Fabrication and evaluation of a sustained-release chitosan-based scaffold embedded with PLGA microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kedong, E-mail: kedongsong@dlut.edu.cn [Dalian R and D Center for Stem Cell and Tissue Engineering, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Liu, Yingchao [Dalian R and D Center for Stem Cell and Tissue Engineering, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Macedo, Hugo M. [Biological Systems Engineering Laboratory, Department of Chemical Engineering, Department of Chemical Engineering, South Kensington Campus, London SW7 2AZ (United Kingdom); Jiang, Lili; Li, Chao; Mei, Guanyu [Dalian R and D Center for Stem Cell and Tissue Engineering, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Liu, Tianqing, E-mail: liutq@dlut.edu.cn [Dalian R and D Center for Stem Cell and Tissue Engineering, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China)

    2013-04-01

    Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27–55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 °C in an aqueous environment of 1% chitosan-based scaffolds were (92.99 ± 2.51) %, (89.66 ± 0.66) % and (73.77 ± 3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24 ± 0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44 ± 1.81) × 10{sup −2} mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a

  6. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    AIM: To prepare polylactic acid microspheres of Erythromycin for Lung targeting.METHEDS: The orthogonal test design was used to optimize the technology,of preparation. Thecharacter of the microspheres, drug release in vitro, stability and tissue distribution were examinedRESULTS: The Erythromycin polylactic acid microspheres was regular in its morphology. Drugwas enveloped in microspheres but not physically mixed with PDLLA. The average particle size was11.65μn with over 94% of the microspheres being in the range of 5~20trn; The drug loading andthe incorporation efciency were 18% and 60% respectively. The microspheres were stable for threemonth at 4 ℃ and room temperature. The in vitro release properties could be expressed by theHiguchi's equation: y = 28.067 + 3.8515t11/2 (r = 0.9834). Comparing with injection, the drug inmicrospheres was more concentrated in lung tissue. CONCLUSION: Erythromycin polylactic acidmicrospheres showed significant sustained release and lung targeting.

  7. Magnetoresponsive Photonic Microspheres with Structural Color Gradient.

    Science.gov (United States)

    Lee, Seung Yeol; Choi, Jongkook; Jeong, Jong-Ryul; Shin, Jung H; Kim, Shin-Hyun

    2017-02-06

    Photonic Janus particles are created by alternately sputtering silica and titania on microspheres in order to obtain a structural color gradient. In addition, the microspheres are rendered magnetoresponsive. The Janus microspheres with optical and magnetic anisotropy enable on-demand control over orientation and structural color through manipulation of an external magnetic field, thereby being useful as active color pigments for reflection-mode displays.

  8. Synthesis of P (St-DVB)/Fe3O4 microspheres and application for oil removal in aqueous environment

    Science.gov (United States)

    Mao, Jianyu; Jiang, Wei; Gu, Junjun; Zhou, Shuai; Lu, Yue; Xie, Tan

    2014-10-01

    In this article, magnetic P (St-DVB)/Fe3O4 microspheres with hollow and porous structure were successfully fabricated by a seed swelling polymerization process for fast and selective absorption of oils from water surface. These microspheres, with unsinkable, magnetic, hydrophobic and oleophilic properties, were used to absorb different oils up to 8.42 times of the particles' weight while repelling water completely. More importantly, the oil-absorbed microspheres could be removed from water surface efficiently via introducing an external magnetic field. This material also shows excellent reusability after washing with ethanol and the oil-absorption capacity of the material was not sharply reduced even after the 10th cycle. The discoveries presented in this study might provide a low-cost, effective, and environmental-friendly approach for the clean-up of oils and organic solvents on the water.

  9. Asymmetrical two-atom entanglement in a coated microsphere

    Energy Technology Data Exchange (ETDEWEB)

    Burlak, G.N. [Center for Research on Engineering and Applied Sciences, Autonomous State University of Morelos, Cuernavaca, Mor. 62210 (Mexico)]. E-mail: gburlak@uaem.mx; Klimov, A.B. [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, Guadalajara, Jalisco, 44420 (Mexico)]. E-mail: klimov@cencar.udg.mx

    2006-12-25

    We study evolution of entanglement of two two-level atoms placed inside a multilayered microsphere. We show that due to inhomogeneity of the optical field modes this entanglement essentially depends on the atomic positions (asymmetrical entanglement) and also on the detuning between the atomic transitions and field frequencies. The robust and complete entanglement can be achieved even in the resonant case when the atoms have different effective coupling constants, and it can be extended in time if the detuning is large enough.

  10. Scaffolds for bone regeneration made of hydroxyapatite microspheres in a collagen matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cholas, Rahmatullah, E-mail: rahmat.cholas@gmail.com; Kunjalukkal Padmanabhan, Sanosh, E-mail: sanosh2001@gmail.com; Gervaso, Francesca; Udayan, Gayatri; Monaco, Graziana; Sannino, Alessandro; Licciulli, Antonio

    2016-06-01

    Biomimetic scaffolds with a structural and chemical composition similar to native bone tissue may be promising for bone tissue regeneration. In the present work hydroxyapatite mesoporous microspheres (mHA) were incorporated into collagen scaffolds containing an ordered interconnected macroporosity. The mHA were obtained by spray drying of a nano hydroxyapatite slurry prepared by the precipitation technique. X-ray diffraction (XRD) analysis revealed that the microspheres were composed only of hydroxyapatite (HA) phase, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the Ca/P ratio to be 1.69 which is near the value for pure HA. The obtained microspheres had an average diameter of 6 μm, a specific surface area of 40 m{sup 2}/g as measured by Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis showed a mesoporous structure with an average pore diameter of 16 nm. Collagen/HA-microsphere (Col/mHA) composite scaffolds were prepared by freeze-drying followed by dehydrothermal crosslinking. SEM observations of Col/mHA scaffolds revealed HA microspheres embedded within a porous collagen matrix with a pore size ranging from a few microns up to 200 μm, which was also confirmed by histological staining of sections of paraffin embedded scaffolds. The compressive modulus of the composite scaffold at low and high strain values was 1.7 and 2.8 times, respectively, that of pure collagen scaffolds. Cell proliferation measured by the MTT assay showed more than a 3-fold increase in cell number within the scaffolds after 15 days of culture for both pure collagen scaffolds and Col/mHA composite scaffolds. Attractive properties of this composite scaffold include the potential to load the microspheres for drug delivery and the controllability of the pore structure at various length scales. - Highlights: • Mesoporous hydroxyapatite microsphere(mHA) synthesized by spray drying method • Porous collagen/mHA composite scaffold made by freeze

  11. Microspheres in Plasma Display Panels

    Science.gov (United States)

    2006-01-01

    Filling small bubbles of molten glass with gases is just as difficult as it sounds, but the technical staff at NASA is not known to shy away from a difficult task. When Microsphere Systems, Inc. (MSI), of Ypsilanti, Michigan, and Imaging Systems Technology, Inc. (IST), of Toledo, Ohio, were trying to push the limits of plasma displays but were having difficulty with the designs, NASA s Glenn Garrett Morgan Commercialization Initiative (GMCI) assembled key personnel at Glenn Research Center and Ohio State University for a brainstorming session to come up with a solution for the companies. They needed a system that could produce hollow, glass micro-sized spheres (microspheres) that could be filled with a variety of gasses. But the extremely high temperature required to force the micro-sized glass bubbles to form at the tip of a metal nozzle resulted in severe discoloration of the microspheres. After countless experiments on various glass-metal combinations, they had turned to the GMCI for help. NASA experts in advanced metals, ceramics, and glass concluded that a new design approach was necessary. The team determined that what was needed was a phosphate glass composition that would remain transparent, and they went to work on a solution. Six weeks later, using the design tips from the NASA team, Tim Henderson, president of MSI, had designed a new system in which all surfaces in contact with the molten glass would be ceramic instead of metal. Meanwhile, IST was able to complete a Phase I Small Business Innovation Research (SBIR) grant supported by the National Science Foundation (NSF) and supply a potential customer with samples of the microspheres for evaluation as filler materials for high-performance insulations.

  12. Immobilization of trypsin onto multifunctional meso-/macroporous core-shell microspheres: A new platform for rapid enzymatic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Gong [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Ping [Key Laboratory of Marine Bioresources and Ecology, College of Life Science, Shenzhen University, Shenzhen 518060 (China); Wang, Zhi-Gang; Sui, Xiao-Jing [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Ji-Lin, E-mail: zjl@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); Ni, Jia-Zuan [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); Key Laboratory of Marine Bioresources and Ecology, College of Life Science, Shenzhen University, Shenzhen 518060 (China)

    2014-02-17

    Graphical abstract: -- Highlights: •A novel microwave-assisted tryptic digestion system. •Characterization with SEM, TEM, EDX, XRD, and FT-IR. •The meso-/macroporous shell structure withthe high affinity and loading capacity of trypsin. •Decrease of digestion time up to less than 1 min. •MALDI-MS and nanoLC-MS analysis with database identification. -- Abstract: A simple, fast, efficient, and reusable microwave-assisted tryptic digestion system which was constructed by immobilization of trypsin onto porous core-shell Fe{sub 3}O{sub 4}@fTiO{sub 2} microspheres has been developed. The nanostructure with magnetic core and titania shell has multiple pore sizes (2.4 and 15.0 nm), high pore volume (0.25 cm{sup 3} g{sup −1}), and large surface area (50.45 m{sup 2} g{sup −1}). For the proteins, the system can realize fast and efficient microwave-assisted tryptic digestion. Various standard proteins (e.g., cytochrome c (cyt-c), myoglobin (MYO), β-lactoglobulin (β-LG), and bovine serum albumin (BSA)) used can be digested in 45 s under microwave radiation, and they can be confidently identified by mass spectrometry (MS) analysis; even the concentration of substrate is as low as 5 ng μL{sup −1}. Furthermore, the system for the 45 s microwave-assisted tryptic digestion is still effective after the trypsin-immobilized microspheres have been reused for 5 times. Importantly, 1715 unique proteins from 10 μg mouse brain proteins can be identified with high confidence after treatment of 45 s microwave-assisted tryptic digestion.

  13. Enhanced photocatalytic performances of hierarchical ZnO/ZnAl2O4 microsphere derived from layered double hydroxide precursor spray-dried microsphere.

    Science.gov (United States)

    Huo, Ruijie; Kuang, Ye; Zhao, Zhiping; Zhang, Fazhi; Xu, Sailong

    2013-10-01

    Layered double hydroxides (LDHs), also called hydrotalcites, have been widely investigated for degradation of dye molecules, in the forms of direct photocatalysts, supports or precursors to ZnO-containing photocatalysts. LDH precursor-derived ZnO/ZnAl2O4 photocatalytic nanostructures have hitherto been created, involving ZnO/ZnAl2O4 powder and templated hierarchical frameworks with laboratory-scale preparations. We herein report a scalable preparation of ZnO/ZnAl2O4 microsphere derived from ZnAl-LDH precursor spray-dried microsphere. Survey of textural properties shows that ZnO/ZnAl2O4 microspheres maintain the hierarchically spherical feature and the relatively large surface area. Photocatalytic evaluation under UV irradiation shows that the ZnO/ZnAl2O4 microspheres exhibit highly enhanced photodegradation performance to methylene blue (MB) in comparison with the commercial ZnO powder. A preferential photodegradation to methyl orange (MO) of the MO/MB mixture was also observed, which was illustrated experimentally in terms of the favorable interaction and distribution between basic MO molecules and the acidic-site ZnO/ZnAl2O4 photocatalyst. Our results may initiate large-scale production of microspheres with promising photocatalytic performances.

  14. Facile Method for Preparation of Silica Coated Monodisperse Superparamagnetic Microspheres

    Directory of Open Access Journals (Sweden)

    Xuan-Hung Pham

    2016-01-01

    Full Text Available This paper presents a facile method for preparation of silica coated monodisperse superparamagnetic microsphere. Herein, monodisperse porous polystyrene-divinylbenzene microbeads were prepared by seeded emulsion polymerization and subsequently sulfonated with acetic acid/H2SO4. The as-prepared sulfonated macroporous beads were magnetized in presence of Fe2+/Fe3+ under alkaline condition and were subjected to silica coating by sol-gel process, providing water compatibility, easily modifiable surface form, and chemical stability. FE-SEM, TEM, FT-IR, and TGA were employed to characterize the silica coated monodisperse magnetic beads (~7.5 μm. The proposed monodisperse magnetic beads can be used as mobile solid phase particles candidate for protein and DNA separation.

  15. Sodium alginate/Na+-rectorite composite microspheres: preparation, characterization, and dye adsorption.

    Science.gov (United States)

    Yang, Lianli; Ma, Xiaoyan; Guo, Naini

    2012-10-01

    Sodium alginate/Na(+)-rectorite (SA/Na(+)REC) intercalated nano-composite microspheres were prepared in an inverse suspension system. The effect of the preparation conditions of SA/Na(+)REC composite microspheres on adsorption capacity for Basic Blue 9 was investigated. The structure and morphology were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the optimal condition was that the amount of Na(+)-rectorite was 2wt%, the amount of cross-linker was 0.384% and the amount of the initiator was 8%. SEM showed that it is porous products with spherical particulate surface. XRD showed that intercalation is formed between Na(+)-rectorite and sodium alginate. The adsorption capacity of SA/Na(+)REC was investigated in comparison with Na(+)-rectorite and sodium alginate using different cationic dyes. The SA/Na(+)REC composite microspheres showed the highest adsorption capacity. The reason lies in the existence of intercalated sodium alginate. It could enlarge the pore structure of microspheres, facilitating the penetration of macromolecular dyes. Copyright © 2012. Published by Elsevier Ltd.

  16. Microsphere integrated microfluidic disk: synergy of two techniques for rapid and ultrasensitive dengue detection.

    Science.gov (United States)

    Hosseini, Samira; Aeinehvand, Mohammad M; Uddin, Shah M; Benzina, Abderazak; Rothan, Hussin A; Yusof, Rohana; Koole, Leo H; Madou, Marc J; Djordjevic, Ivan; Ibrahim, Fatimah

    2015-11-09

    The application of microfluidic devices in diagnostic systems is well-established in contemporary research. Large specific surface area of microspheres, on the other hand, has secured an important position for their use in bioanalytical assays. Herein, we report a combination of microspheres and microfluidic disk in a unique hybrid platform for highly sensitive and selective detection of dengue virus. Surface engineered polymethacrylate microspheres with carefully designed functional groups facilitate biorecognition in a multitude manner. In order to maximize the utility of the microspheres' specific surface area in biomolecular interaction, the microfluidic disk was equipped with a micromixing system. The mixing mechanism (microballoon mixing) enhances the number of molecular encounters between spheres and target analyte by accessing the entire sample volume more effectively, which subsequently results in signal amplification. Significant reduction of incubation time along with considerable lower detection limits were the prime motivations for the integration of microspheres inside the microfluidic disk. Lengthy incubations of routine analytical assays were reduced from 2 hours to 5 minutes while developed system successfully detected a few units of dengue virus. Obtained results make this hybrid microsphere-microfluidic approach to dengue detection a promising avenue for early detection of this fatal illness.

  17. Suspension Plasma Spray Fabrication of Nanocrystalline Titania Hollow Microspheres for Photocatalytic Applications

    Science.gov (United States)

    Ren, Kun; Liu, Yi; He, Xiaoyan; Li, Hua

    2015-10-01

    Hollow inorganic microspheres with controlled internal pores in close-cell configuration are usually constructed by submicron-sized particles. Fast and efficient large-scale production of the microspheres with tunable sizes yet remains challenging. Here, we report a suspension plasma spray route for making hollow microspheres from nano titania particles. The processing permits most nano particles to retain their physiochemical properties in the as-sprayed microspheres. The microspheres have controllable interior cavities and mesoporous shell of 1-3 μm in thickness. Spray parameters and organic content in the starting suspension play the key role in regulating the efficiency of accomplishing the hollow sphere structure. For the ease of collecting the spheres for recycling use, ferriferous oxide particles were used as additives to make Fe3O4-TiO2 hollow magnetic microspheres. The spheres can be easily recycled through external magnetic field collection after each time use. Photocatalytic anti-bacterial activities of the hollow spheres were assessed by examining their capability of degrading methylene blue and sterilizing Escherichia coli bacteria. Excellent photocatalytic performances were revealed for the hollow spheres, giving insight into their potential versatile applications.

  18. CO2 Biofixation of Actinobacillus succinogenes Through Novel Amine-Functionalized Polystyrene Microsphere Materials.

    Science.gov (United States)

    Zhu, Wenhao; Li, Qiang; Dai, Ning

    2017-02-01

    CO2-derived succinate production was enhanced by Actinobacillus succinogenes through polystyrene (PSt) microsphere materials for CO2 adsorption in bioreactor, and the adhesion forces between A. succinogenes bacteria and PSt materials were characterized. Synthesized uniformly sized and highly cross-linked PSt microspheres had high specific surface areas. After modification with amine functional groups, the novel amine-functionalized PSt microspheres exhibited a high adsorption capacity of 25.3 mg CO2/g materials. After addition with the functionalized microspheres into the culture broth, CO2 supply to the cells increased. Succinate production by A. succinogenes can be enhanced from 29.6 to 48.1 g L(-1). Moreover, the characterization of interaction forces between A. succinogenes cells and the microspheres indicated that the maximal adhesive force was about 250 pN. The amine-functionalized PSt microspheres can adsorb a large amount of CO2 and be employed for A. succinogenes anaerobic cultivation in bioreactor for high-efficiency production of CO2-derived succinate.

  19. Preparation of phosphorus-containing silica glass microspheres for radiotherapy of cancer by ion implantation.

    Science.gov (United States)

    Kawashita, M; Miyaji, F; Kokubo, T; Suzuki, Y; Kajiyama, K

    1999-08-01

    A chemically durable glass microsphere containing a large amount of phosphorus is useful for in situ irradiation of cancers, since they can be activated to be a beta-emitter with a half-life of 14.3 d by neutron bombardment. When the activated microspheres are injected to the tumors, they can irradiate the tumors directly with beta-rays without irradiating neighboring normal tissues. In the present study, P+ ion was implanted into silica glass microspheres of 25 microm in average diameter at 50 keV with nominal doses of 2.5 x 10(16) and 3.35 x 10(1)6 cm(-2). The glass microspheres were put into a stainless container and the container was continuously shaken during the ion implantation so that P+ ion was implanted into them uniformly. The implanted phosphorus was localized in deep regions of the glass microsphere with the maximum concentration at about 50 nm depth without distributing up to the surface even for a nominal dose of 3.35 x 10(16) cm(-2). Both samples released phosphorus and silicon into water at 95 degrees C for 7 d. On the basis of the previous study on P+-implanted silica glass plates, the silica glass microspheres containing more phosphorus which is desired for actual treatment could be obtained, without losing high chemical durability, if P+ ion would be implanted at higher energy than 50 keV to be localized in deeper region.

  20. Microsphere-integrated gelatin-siloxane hybrid scaffolds for bone tissue engineering :in vitro bioactivity & antibacterial activity

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Microsphere integrated gelatin-siloxane hybrid scaffolds were successfully synthesized by using a combined sol-gel processing,post-gelation soaking and freeze-drying process.A bone-like apatite layer was able to form in the Ca2+-containing porous hybrids upon soaking in a simulated body fluid (SBF) up to 1 day.The rate of gentamicin sulfate (GS) release from the GS-loaded gelatin-siloxane hybrid microsphere became constant after a 4 h burst.The antibacterial activity was assessed by the agar diffusion test (ADT) and the bactericidal effect test.It is evident that the as-synthesized porous scaffolds have excellent bioactivity and antibacterial activity,and may be favorable in bone tissue engineering.

  1. Solvothermal synthesis and photocatalytic properties of NiO ultrathin nanosheets with porous structure

    Energy Technology Data Exchange (ETDEWEB)

    Qing, Zhang; Haixia, Liu; Huali, Li; Yu, Liu; Huayong, Zhang; Tianduo, Li, E-mail: litianduo@163.com

    2015-02-15

    Highlights: • Hierarchical NiO microspheres with ultrathin and porous structure were prepared by solvothermal method. • The nanoparticles were grown by the constant direction with the preferred orientation. • Structural features of NiO microspheres were characterized by means of different techniques. • High temperature annealing processing conducive to the formation of the porous feature. • NiO microspheres had better photocatalytic activity and stable cyclability for methylene blue dye under UV irradiation than commercial NiO. - Abstract: Hierarchical NiO microspheres, composed of ultrathin nanosheets with porous structure, are prepared through a facile solvothermal route followed by a calcination process. First, the precursor Ni{sub 3}(NO{sub 3}){sub 2}(OH){sub 4} hierarchical architectures assembled by irregular nanosheets were synthesized through urea assisted precipitation. Second, the NiO hierarchical architecture was obtained from the precursor by a simple calcination procedure without changing their morphologies. The resultant products were characterized by XRD, SEM, TEM, TG, FT-IR and BET analysis techniques. The XRD pattern showed that the sample exhibited a rocksalt cubic phase structure after calcined at 500 °C for 2 h. The SEM and TEM images demonstrated that the as-prepared NiO were microspheres composed of ultrathin nanosheets with porous structure. The catalytic efficiency of the NiO nanomaterials is evaluated by the photocatalytic degradation of methylene blue (MB). The obtained NiO displayed the excellent degradable ability and stable cyclability to MB dye, which may be attributed to its unique hierarchical characteristics: ultrathin-porous microstructure.

  2. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    YANGFan; YANBing; 等

    2002-01-01

    AIM:To prepare polylactiv acid microspheres of Erythromycin for Lung targeting.METHEDS:The orthogonal test design was used to optimize the technology of preparation.The character of the microspheres,drug release in vitro,stabiligy and tissue distribution were examined. RESULTS:The Erythromycin polylatic acid microspheres was regular in its morphology.Drug was enveloped in microspheres but not physically mixed with PDLLA.The average particle size was 11.65μm with over 94% of the microspheres being in the range of 5-20μm;The drug loading and the incorporation efficiency were 18% and 60% respectively.The microspheres were stable for three month at 4℃ and room temperature.The in vitro release properties could be expressed by the Higuchi′s equation:y=28.067+3.8515t1/2(r=0.9834).Comparing with injection,the drug in microspheres was more concentrated in lung tissue.CONLUSION:Erythromycin polylactic acid microspheres showed significant sustained release and lung targeting.

  3. Microencapsulation and microspheres for food applications

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    This book provides an update on the latest developments, challenges, and opportunities in the highly expanding field of microencapsulation and microspheres for food applications, examining the various types of microspheres and microcapsules essential to those who need to develop stable and impermeab

  4. γ-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres: preparation, formation mechanism, magnetic property, and application in water treatment.

    Science.gov (United States)

    Xu, Jing-San; Zhu, Ying-Jie

    2012-11-01

    In this paper, we report the preparation of γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres by a solvothermal combined with precursor thermal conversion method. These γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres were constructed by three-dimensional self-assembly of nanosheets, forming porous nanostructures. The effects of experimental parameters including molar ratio of reactants and reaction temperature on the precursors were studied. The time-dependent experiments indicated that the Ostwald ripening was responsible for the formation of the hierarchically nanostructured hollow microspheres of the precursors. γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres were obtained by the thermal transformation of the precursor hollow microspheres. Both γ-Fe(2)O(3) and Fe(3)O(4) hierarchically nanostructured hollow microspheres exhibited a superparamagnetic property at room temperature and had the saturation magnetization of 44.2 and 55.4 emu/g, respectively, in the applied magnetic field of 20 KOe. Several kinds of organic pollutants including salicylic acid (SA), methylene blue (MB), and basic fuchsin (BF) were chosen as the model water pollutants to evaluate the removal abilities of γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres. It was found that γ-Fe(2)O(3) hierarchically nanostructured hollow microspheres showed a better adsorption ability over SA than MB and BF. However, Fe(3)O(4) hierarchically nanostructured hollow microspheres had the best performance for adsorbing MB. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Dextran-based microspheres as controlled delivery systems for proteins

    NARCIS (Netherlands)

    Vlugt-Wensink, K.D.F.

    2007-01-01

    Dextran-based microspheres as controlled delivery systems for proteins Dextran based microspheres are investigated as controlled delivery system for proteins. Microspheres were prepared by polymerization of dex-HEMA in an aqueous two-phase system of dex-HEMA and PEG. Protein loaded microspheres are

  6. Spectrally resolved resonant propulsion of dielectric microspheres

    CERN Document Server

    Li, Yangcheng; Limberopoulos, Nicholaos I; Urbas, Augustine M; Astratov, Vasily N

    2015-01-01

    Use of resonant light forces opens up a unique approach to high-volume sorting of microspherical resonators with much higher uniformity of resonances compared to that in coupled-cavity structures obtained by the best semiconductor technologies. In this work, the spectral response of the propulsion forces exerted on polystyrene microspheres near tapered microfibers is directly observed. The measurements are based on the control of the detuning between the tunable laser and internal resonances in each sphere with accuracy higher than the width of the resonances. The measured spectral shape of the propulsion forces correlates well with the whispering-gallery mode resonances in the microspheres. The existence of a stable radial trap for the microspheres propelled along the taper is demonstrated. The giant force peaks observed for 20-{\\mu}m spheres are found to be in a good agreement with a model calculation demonstrating an efficient use of the light momentum for propelling the microspheres.

  7. Hydroxyapatite nanocrystal coating on biodegradable microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Masahiro [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565 (Japan); Furuzono, Tsutomu, E-mail: furuzono@ri.ncvc.go.jp [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565 (Japan)

    2010-10-15

    Nano-sized single crystals of calcined hydroxyapatite (HAp) were uniformly coated on poly(L-lactic acid) (PLLA) microspheres through the ionic interaction between calcium ions on the HAp nanocrystal and carboxyl groups on the PLLA microsphere. In order to coat the substrate with HAp nanocrystals through ionic interaction, the surfaces of the PLLA microspheres were hydrolyzed in an alkaline aqueous solution at pH 11.0 for 1 h at room temperature. The interaction between the HAp nanocrystals and the carboxyl groups originating from PLLA end groups was estimated by Fourier transform infrared spectroscopy. The alkali-treated PLLA microspheres were coated with HAp nanocrystals by immersing the microspheres in an ethanol dispersion of HAp nanocrystals followed by washing in an ultrasonic bath.

  8. Porous carbons

    Indian Academy of Sciences (India)

    Satish M Manocha

    2003-02-01

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor adsorption capacities. On activation, these exhibit increased adsorption volumes of 0.5–0.8 cm3 /gm and surface areas of 700–1800 m2 /gm depending on activation conditions, whether physical or chemical. Former carbons possess mixed pore size distribution while chemically activated carbons predominantly possess micropores. Thus, these carbons can be used for adsorption of wide distributions of molecules from gas to liquid. The molecular adsorption within the pores is due to single layer or multilayer molecule deposition at the pore walls and hence results in different types of adsorption isotherm. On the other hand, activated carbon fibres with controlled microporous structure and surface area in the range of 2500 m2 /gm can be developed by controlled pyrolysis and physical activation of amorphous carbon fibres. Active carbon fibres with unmatchable pore structure and surface characteristics are present and futuristic porous materials for a number of applications from pollution control to energy storage.

  9. Synthesis of SnO{sub 2} hollow microspheres from ultrasonic atomization and their role in hydrogen sensing

    Energy Technology Data Exchange (ETDEWEB)

    Patil, L.A., E-mail: plalchand_phy_aml@yahoo.co.in [Nanomaterials Research Lab., Department of Physics, Pratap College, Amalner 425401, Maharashtra (India); Shinde, M.D.; Bari, A.R.; Deo, V.V. [Nanomaterials Research Lab., Department of Physics, Pratap College, Amalner 425401, Maharashtra (India)

    2011-04-25

    Nanostructured SnO{sub 2} hollow microspheres were synthesized using ultrasonic atomization technique. It is interesting that hollow microspheres could be prepared from ultrasonic atomization technique without any aid of template and surfactant. X-ray powder diffraction (XRD) confirmed the material to be SnO{sub 2} having tetragonal structure. Average crystallite size calculated from X-ray diffractogram using Scherer's equation was found to be 8.45 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the microscopic study of fine powder particles. Powder consists of hollow microspheres of average diameter of 0.58 {mu}m as well as nanoparticles of average diameter of 6 nm. The sensors fabricated from such powder show high hydrogen (1000 ppm) response (S = 2379) under the optimized experimental conditions. Sensor performance merits, such as, high hydrogen response, high hydrogen selectivity, short response time (2 s) and quick recovery time (15 s) may be due to both nanocrystallites and hollow microspheres associated in SnO{sub 2} sensing material. The dramatic change in gas response was explained by the rapid diffusion of the target gas through the nano-porous structure of SnO{sub 2} hollow microspheres.

  10. N-(furfural) chitosan hydrogels based on Diels-Alder cycloadditions and application as microspheres for controlled drug release.

    Science.gov (United States)

    Montiel-Herrera, Marcelino; Gandini, Alessandro; Goycoolea, Francisco M; Jacobsen, Neil E; Lizardi-Mendoza, Jaime; Recillas-Mota, Maricarmen; Argüelles-Monal, Waldo M

    2015-09-01

    In this study, chitosan was chemically modified by reductive amination in a two-step process. The synthesis of N-(furfural) chitosan (FC) was confirmed by FT-IR and (1)H NMR analysis, and the degrees of substitution were estimated as 8.3 and 23.8%. The cross-linkable system of bismaleimide (BM) and FC shows that FC shared properties of furan-maleimide chemistry. This system produced non-reversible hydrogel networks by Diels-Alder cycloadditions at 85 °C. The system composed of BM and FC (23.8% substitution) generated stronger hydrogel networks than those of FC with an 8.3% degree of substitution. Moreover, the FC-BM system was able to produce hydrogel microspheres. Environmental scanning electron microscopy revealed the surface of the microspheres to be non-porous with small protuberances. In water, the microspheres swelled, increasing their volume by 30%. Finally, microspheres loaded with methylene blue were able to release the dye gradually, obeying second-order kinetics for times less than 600 min. This behavior suggests that diffusion is governed by the relaxation of polymer chains in the swelled state, thus facilitating drug release outside the microspheres.

  11. Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Asoh, Hidetaka [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)], E-mail: asoh@cc.kogakuin.ac.jp; Uchibori, Kota; Ono, Sachiko [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)

    2009-07-15

    The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

  12. Porous bioactive materials

    Science.gov (United States)

    Zhang, Kai

    Bioactive materials chemically bond to tissues through the development of biologically active apatite. Porous structures in biomaterials are designed to enhance bioactivity, grow artificial tissues and achieve better integration with host tissues in the body. The goal of this research is to design, fabricate and characterize novel porous bioactive materials. 3D ordered macroporous bioactive glasses (3DOM-BGs, pore size: 200--1000 nm) were prepared using a sol-gel process and colloidal crystal templates. 3DOM-BGs are more bioactive and degradable than mesoporous (pore size simulated body fluid (SBF). Apatite formation and 3DOM-BG degradation rates increased with the decrease of soaking ratio. Apatite induction time in SBF increased with 3DOM-BG calcination temperature (600--800°C). Apatite formation and 3DOMBG degradation were slightly enhanced for a phosphate containing composition. Large 3DOM-BG particles formed less apatite and degraded less completely as compared with small particles. An increase in macropore size slowed down 3DOM-BG degradation and apatite formation processes. After heating the converted apatite at a temperature higher than 700°C, highly crystalline hydroxyapatite and a minor tri-calcium phosphate phase formed. 3DOM-BGs have potential applications as bone/periodontal fillers, and drugs and biological factors delivery agents. Anchoring artificial soft tissues (e.g., cartilage) to native bone presents a challenge. Porous polymer/bioactive glass composites are candidate materials for engineering artificial soft tissue/bone interfaces. Porous composites consisting of polymer matrices (e.g., polysulfone, polylactide, and polyurethane) and bioactive glass particles were prepared by polymer phase separation techniques adapted to include ceramic particles. Composites (thickness: 200--500 mum) have asymmetric structures with dense top layers and porous structures beneath. Porous structures consist of large pores (>100 mum) in a network of smaller (<10

  13. Biofunctionalization of silica microspheres for protein separation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Binjie [Institute of Immunology, Henan University, Kaifeng 475004 (China); Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zou, Xueyan [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhao, Yanbao, E-mail: yanbaozhao@126.com [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Sun, Lei [Institute of Immunology, Henan University, Kaifeng 475004 (China); Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Li, Shulian [Institute of Immunology, Henan University, Kaifeng 475004 (China)

    2013-07-01

    Mercapto-silica (SiO{sub 2}–SH) microspheres were prepared via direct hydrolysis of 3-mercaptopropyltrimethoxysilane (MPS) in a basic aqueous solution. The content of surface thiol group (-SH) of SiO{sub 2}–SH microspheres was measured by Ellman's reagent method and X-ray photoelectron spectroscopy (XPS) and the content of surface thiol group of SiO{sub 2}–SH microspheres is strongly dependent on the reaction conditions. The thermal stability of SiO{sub 2}–SH microspheres was evaluated by thermogravimetric (TG) analysis, which tended to reduce with the increase of content of surface thiol groups. SiO{sub 2}–SH microspheres can be easily modified with reduced glutathione (GSH) to generate SiO{sub 2}–GSH microspheres for the affinity separation of Glutathione S-transferase (GST). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to examine the validity of the separation procedure. The results showed that SiO{sub 2}–GSH microspheres were efficient in GST affinity separation from mixed proteins. - Graphical abstract: The prepared SiO{sub 2}–SH microsphere binding reduced glutathione (SiO{sub 2}–GSH) as affinity precipitation support can capture selectively Glutathione S-transferase (GST) from mixed protein solution. Highlights: ► SiO{sub 2}–SH microspheres were prepared in water using one-pot synthesis. ► The content of surface -SH was investigated by Ellman method and XPS spectra. ► The ratio of -SH to mass strongly depends on the reaction conditions. ► SiO{sub 2}–SH microspheres were biofunctionalized by glutathione. ► SiO{sub 2}–GSH can be used to capture selectively Glutathione S-transferase.

  14. Femtosecond laser ablation of highly oriented pyrolytic graphite: a green route for large-scale production of porous graphene and graphene quantum dots.

    Science.gov (United States)

    Russo, Paola; Hu, Anming; Compagnini, Giuseppe; Duley, Walter W; Zhou, Norman Y

    2014-02-21

    Porous graphene (PG) and graphene quantum dots (GQDs) are attracting attention due to their potential applications in photovoltaics, catalysis, and bio-related fields. We present a novel way for mass production of these promising materials. The femtosecond laser ablation of highly oriented pyrolytic graphite (HOPG) is employed for their synthesis. Porous graphene (PG) layers were found to float at the water-air interface, while graphene quantum dots (GQDs) were dispersed in the solution. The sheets consist of one to six stacked layers of spongy graphene, which form an irregular 3D porous structure that displays pores with an average size of 15-20 nm. Several characterization techniques have confirmed the porous nature of the collected layers. The analyses of the aqueous solution confirmed the presence of GQDs with dimensions of about 2-5 nm. It is found that the formation of both PG and GQDs depends on the fs-laser ablation energy. At laser fluences less than 12 J cm(-2), no evidence of either PG or GQDs is detected. However, polyynes with six and eight carbon atoms per chain are found in the solution. For laser energies in the 20-30 J cm(-2) range, these polyynes disappeared, while PG and GQDs were found at the water-air interface and in the solution, respectively. The origin of these materials can be explained based on the mechanisms for water breakdown and coal gasification. The absence of PG and GQDs, after the laser ablation of HOPG in liquid nitrogen, confirms the proposed mechanisms.

  15. Trans-arterial chemo-embolization (TACE, with either lipiodol (traditional TACE or drug-eluting microspheres (precision TACE, pTACE in the treatment of hepatocellular carcinoma: efficacy and safety results from a large mono-institutional analysis

    Directory of Open Access Journals (Sweden)

    Marmorale Cristina

    2010-12-01

    Full Text Available Abstract More data about TACE and pTACE seem necessary to better define the global treatment strategy for HCC. Aim of our analysis was to evaluate the role of TACE, either with lipiodol (traditional or drug-eluting microspheres in terms of response rate (RR, time to progression (TTP, overall survival (OS and toxicity in HCC. Patients with HCC undergoing traditional TACE or pTACE (either alone or in combination with other treatment options were eligible One hundred and fifty patients were analyzed. In the global patient population median OS was 46 months for lipiodol TACE and 19 months for pTACE (p At multivariate analysis, age, the Okuda stage, type of TACE and number of TACE proved to be independent prognostic factors influencing overall survival. In our experience, lipiodol TACE showed a better OS and TTP over pTACE, without difference in toxicity profile and RR. Among the staging systems analyzed only the Okuda stage seemed able to reliably predict patients outcome.

  16. Transport and attenuation of carboxylate-modified latex microspheres in fractured rock laboratory and field tracer tests

    Science.gov (United States)

    Becker, M.W.; Reimus, P.W.; Vilks, P.

    1999-01-01

    Understanding colloid transport in ground water is essential to assessing the migration of colloid-size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks of pathogen contamination in drinking water wells. Much has been learned through laboratory and field-scale colloid tracer tests, but progress has been hampered by a lack of consistent tracer testing methodology at different scales and fluid velocities. This paper presents laboratory and field tracer tests in fractured rock that use the same type of colloid tracer over an almost three orders-of-magnitude range in scale and fluid velocity. Fluorescently-dyed carboxylate-modified latex (CML) microspheres (0.19 to 0.98 ??m diameter) were used as tracers in (1) a naturally fractured tuff sample, (2) a large block of naturally fractured granite, (3) a fractured granite field site, and (4) another fractured granite/schist field site. In all cases, the mean transport time of the microspheres was shorter than the solutes, regardless of detection limit. In all but the smallest scale test, only a fraction of the injected microsphere mass was recovered, with the smaller microspheres being recovered to a greater extent than the larger microspheres. Using existing theory, we hypothesize that the observed microsphere early arrival was due to volume exclusion and attenuation was due to aggregation and/or settling during transport. In most tests, microspheres were detected using flow cytometry, which proved to be an excellent method of analysis. CML microspheres appear to be useful tracers for fractured rock in forced gradient and short-term natural gradient tests, but longer residence times may result in small microsphere recoveries.Understanding colloid transport in ground water is essential to assessing the migration of colloid-size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks

  17. Fabrication of porous alumina templates with a large-scale tunable interpore distance in a H2C2O4-C2H5OH-H2O solution

    Institute of Scientific and Technical Information of China (English)

    LI Yi; LING ZhiYuan; WANG JinChi; GHEN ShuoShuo; HU Xing; HE XinHua

    2008-01-01

    Highly ordered porous alumina templates with a large-scale tunable interpore distance (100-445 nm) have been successfully fabricated under an electric field of 40-180 V by modifying oxalic acid solution with adequate alcohol. The results under our experimental conditions show that the phenomena of burning and breakdown during the high-field anodization process can be avoided by adding a proper amount of alcohol to the oxalic acid solution, An excellent linear relationship between interpore dis-tance and anodization voltage is obtained under 40-170 V, and the maximum anodization voltage that could be used to avoid burning and breakdown is 180 V.

  18. Porous Ascend

    DEFF Research Database (Denmark)

    Riiber, Jacob; Tamke, Martin; Ramsgaard Thomsen, Mette

    2012-01-01

    The Porous Ascend project investigates how algorithmic and generative approaches allows for the utilization of complex, and by other means inaccessible, ways of devising the schema by which we arrange the parts of an architectural object. It does so by pursuing to physically realize a structure...... of folded elements, based on the concept of applying recursion to the geometry of the non-periodic Penrose tiling. Within this process the project explores questions regarding the making of bespoke digital design tools, digital production, material behaviour and assemblage strategies. The project points...... with an outside and an efficient distribution of specific material behaviour....

  19. Preparation of polyvinylpyrrodione microspheres by dispersion polymerization

    Institute of Scientific and Technical Information of China (English)

    Linfeng ZHAI; Tiejun SHI; Hualin WANG

    2009-01-01

    The preparation of polyvinylpyrrolidone (PVP) microspheres in ethyl acetate by dispersion polymerization with N-vinylpyrrolidone (NVP) as initial monomer, poly(N-vinylpyrrolidone-co-vinyl acetate) (P (NVP-co-VAc)) as dispersant, and 2, 2'-azobisisobutyr-onitrile(AIBN) as initiator is reported. The influences of monomer concentration, dispersant concentration and initiator concentration on the size of PVP microspheres as well as the monomer conversion were studied. The structure and properties of PVP microspheres were analyzed. The results show that the prepared PVP micro-spheres have a mean diameter of 3-4 μm. With an increase in NVP concentration, the size and the molecular weight of the PVP microspheres as well as the monomer conversion all increase. With increasing P(NVP-co-VAc) concentra-tions, the PVP molecular weight and monomer conversion both increase while the size of the microspheres becomes smaller. As the concentration of AIBN increases, the microsphere size and monomer conversion increase whereas the PVP molecular weight decreases. The PVP prepared by dispersion polymerization has a crystal structure, and its molecular weight is lower compared to that prepared by solution polymerization.

  20. Formation of core-shell-structured Zn2SnO4-carbon microspheres with superior electrochemical properties by one-pot spray pyrolysis.

    Science.gov (United States)

    Hong, Young Jun; Kang, Yun Chan

    2015-01-14

    Core-shell structured Zn2SnO4-carbon microspheres with different carbon contents are prepared by one-pot spray pyrolysis without any further heating process. A Zn2SnO4-carbon composite microsphere is prepared from one droplet containing Zn and Sn salts and polyvinylpyrrolidone (PVP). Melted PVP moves to the outside of the composite microsphere during the drying stage of the droplet. In addition, melting of the phase separated metal salts forms the dense core. Carbonization of the phase separated PVP forms the textured and porous thick carbon shell. The discharge capacities of the core-shell structured Zn2SnO4-carbon microspheres for the 2(nd) and 120(th) cycles at a current density of 1 A g(-1) are 864 and 770 mA h g(-1), respectively. However, the discharge capacities of the bare Zn2SnO4 microspheres prepared by the same process without PVP for the 2(nd) and 120(th) cycles are 1106 and 81 mA h g(-1), respectively. The stable and reversible discharge capacities of the Zn2SnO4-carbon composite microspheres prepared from the spray solution with 15 g PVP decrease from 894 to 528 mA h g(-1) as current density increases from 0.5 to 5 A g(-1).

  1. Characterization of a Polyamine Microsphere and Its Adsorption for Protein

    Directory of Open Access Journals (Sweden)

    Huixian Wei

    2012-12-01

    Full Text Available A novel polyamine microsphere, prepared from the water-in-oil emulsion of polyethylenimine, was characterized. The investigation of scanning electron microscopy showed that the polyamine microsphere is a regular ball with a smooth surface. The diameter distribution of the microsphere is 0.37–4.29 μm. The isoelectric point of the microsphere is 10.6. The microsphere can adsorb proteins through the co-effect of electrostatic and hydrophobic interactions. Among the proteins tested, the highest value of adsorption of microsphere, 127.8 mg·g−1 microsphere, was obtained with lipase. In comparison with other proteins, the hydrophobic force is more important in promoting the adsorption of lipase. The microsphere can preferentially adsorb lipase from an even mixture of proteins. The optimum temperature and pH for the selective adsorption of lipase by the microsphere was 35 °C and pH 7.0.

  2. Method for dialysis on microchips using thin porous polymer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anup K. (San Francisco, CA); Kirby, Brian J. (San Francisco, CA); Shepodd, Timothy J. (Livermore, CA)

    2009-05-19

    Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

  3. Dialysis on microchips using thin porous polymer membranes

    Science.gov (United States)

    Singh, Anup K.; Kirby, Brian J.; Shepodd, Timothy J.

    2007-09-04

    Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and form a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

  4. Injectable PLGA microsphere/calcium phosphate cements: physical properties and degradation characteristics.

    Science.gov (United States)

    Habraken, W J E M; Wolke, J G C; Mikos, A G; Jansen, J A

    2006-01-01

    Calcium phosphate (CaP) cements show an excellent biocompatibility and often have a high mechanical strength, but in general degrade relatively slow. To increase degradation rates, macropores can be introduced into the cement, e.g., by the inclusion of biodegradable microspheres into the cement. The aim of this research is to develop an injectable PLGA microsphere/CaP cement with sufficient setting/cohesive properties and good mechanical and physical properties. PLGA microspheres were prepared using a water-in-oil-in-water double-emulsion technique. The CaP-cement used was Calcibon, a commercially available hydroxyapatite-based cement. 10:90 and 20:80 dry wt% PLGA microsphere/CaP cylindrical scaffolds were prepared as well as microporous cement (reference material). Injectability, setting time, cohesive properties and porosity were determined. Also, a 12-week degradation study in PBS (37 degree C) was performed. Results showed that injectability decreased with an increase in PLGA microsphere content. Initial and final setting time of the PLGA/CaP samples was higher than the microporous sample. Porosity of the different formulations was 40.8% (microporous), 60.2% (10:90) and 69.3% (20:80). The degradation study showed distinct mass loss and a pH decrease of the surrounding medium starting from week 6 with the 10:90 and 20:80 formulations, indicating PLGA erosion. Compression strength of the PLGA microsphere/CaP samples decreased siginificantly in time, the microporous sample remained constant. After 12 weeks both PLGA/CaP samples showed a structure of spherical micropores and had a compressive strength of 12.2 MPa (10:90) and 4.3 MPa (20:80). Signs of cement degradation were also found with the 20:80 formulation. In conclusion, all physical parameters were well within workable ranges with both 10:90 and 20:80 PLGA microsphere/CaP cements. After 12 weeks the PLGA was totally degraded and a highly porous, but strong scaffold remained.

  5. Preparation of Fe3O4/P(GMA-co-EGDMA) magnetic composite microspheres with high specific surface area by deposition of porous template%模板沉积法制备大孔高比表面积Fe3O4/P( GMA-co-EGDMA)磁性复合微球

    Institute of Scientific and Technical Information of China (English)

    张宝亮; 张秋禹; 张和鹏; 范新龙; 厉向杰; 雷星锋

    2012-01-01

    A simple method for preparation of Fe3O4/P ( GMA-co-EGDMA) magnetic composite microspheres using microporous P(GMA-co-EGDMA) microspheres copolymerized with glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) as template is reported in this paper. The preparation process included soaking of ferrous ion and ferric ion and coprecipitation in the presence of OH" . The influences of soaking temperature, soaking time, coprecipitation temperature and deposition times on magnetic content of magnetic composite microspheres were studied. The optimum preparation process of microporous Fe3O4/P (GMA-co-EGDMA) magnetic composite microspheres was as follows: microporous P (GMA-co-EGDMA) microspheres were soaked at 50°Cfor 4 h, coprecipitation temperature and time were 70°C and 1 h respectively. The magnetic content of magnetic composite microsphereswas 45. 24% when the deposition process was repeated 4 times. The morphology, magnetic properties, magnetic content, pore performance and particle size distribution of Fe3O4/P (GMA-co-EGDMA) were determined by SEM, TGA, XRD, mercury porosimeter and laser particle sizer. It was found that the range of particle size of Fe3O4/P (GMA-co-EGDMA) was 100~200 jmm and average particle size was 162 j^m, specific saturation magnetization was 10. 92 emu ? G~J , average pore diameter and specific surface area were 60 nm and 116 m2 ? G"1 respectively.%介绍了一种以大孔高比表面积甲基丙烯酸缩水甘油酯(GMA)与二甲基丙烯酸乙二醇酯(EGDMA)共聚交联微球[P(GMA-co-EGDMA)]为模板制备磁性复合微球的简单方法.制备过程包括Fe3+和Fe2+的浸入、OH-作用下孔内铁离子的共沉淀两步.在此过程中考察了浸泡温度、浸泡时间、共沉淀温度以及沉积次数对微球磁含量的影响,确定最佳制备工艺为50℃浸泡4h,70℃反应1h,如此反复4次磁含量可以达到45.24%.并通过SEM、VSM、XRD、TGA及压汞仪、激光粒度仪等手段对Fe3O4/P( GMA

  6. Highly porous thermoelectric nanocomposites with low thermal conductivity and high figure of merit from large-scale solution-synthesized Bi{sub 2}Te{sub 2.5}Se{sub 0.5} hollow nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Biao; Wu, Yue [Department of Chemical and Biological Engineering, Iowa State University, Ames, IA (United States); Ames Laboratory, Department of Energy, Ames, IA (United States); Feng, Tianli; Ruan, Xiulin [Department of Mechanical Engineering, Purdue University, West Lafayette, IN (United States); Agne, Matthias T.; Snyder, G. Jeffery [Department of Materials Science and Engineering, Northwestern University, Evanston, IL (United States); Zhou, Lin [Ames Laboratory, Department of Energy, Ames, IA (United States)

    2017-03-20

    To enhance the performance of thermoelectric materials and enable access to their widespread applications, it is beneficial yet challenging to synthesize hollow nanostructures in large quantities, with high porosity, low thermal conductivity (κ) and excellent figure of merit (z T). Herein we report a scalable (ca. 11.0 g per batch) and low-temperature colloidal processing route for Bi{sub 2}Te{sub 2.5}Se{sub 0.5} hollow nanostructures. They are sintered into porous, bulk nanocomposites (phi 10 mm x h 10 mm) with low κ (0.48 W m{sup -1} K{sup -1}) and the highest z T (1.18) among state-of-the-art Bi{sub 2}Te{sub 3-x}Se{sub x} materials. Additional benefits of the unprecedented low relative density (68-77 %) are the large demand reduction of raw materials and the improved portability. This method can be adopted to fabricate other porous phase-transition and thermoelectric chalcogenide materials and will pave the way for the implementation of hollow nanostructures in other fields. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Organic aerogel microspheres and fabrication method therefor

    Science.gov (United States)

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1996-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  8. Synthesis of PGMA Microspheres with Amino Groups for High-capacity Adsorption of Cr(VI) by Cerium Initiated Graft Polymerizatio

    Institute of Scientific and Technical Information of China (English)

    李鹏飞; 杨良嵘; 何秀琼; 王娟; 孔鹏; 邢慧芳; 刘会洲

    2012-01-01

    Abstract A novel polyglycidylmethacrylate (PGMA) microspheres with high adsorption capacity of Cr(VI) was prepared by cerium(IV) initiated graft polymerization of tentacle-type polymer chains with amino group on polymer microspheres with hydroxyl groups. The micron-sized PGMA microspheres were prepared by a dispersion polym erization method and subsequently modified by ring-opening reaction to introduce functional hydroxyl groups. The polymer microspheres were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the polymer microspheres had an average diameter of 5 m with uniform size distribution. The free amino group content was determined to be 5.13 mmol·g^-1 for g;PGMA-NH2 microspheres by potentiometric and conductometric titration methods. The Cr(VI) adsorption results indicated that the graft polymerization of tentacle-type polymer chains on the polymer microspheres could produce adsorbents with high adsorption capacity (500 mg-g-l). The polymer microspheres with grafted tentacle polymer chains have potenial application in large-scale removal of Cr(VI) in aqueous solution.

  9. Microsphere integrated microfluidic disk: synergy of two techniques for rapid and ultrasensitive dengue detection

    Science.gov (United States)

    Hosseini, Samira; Aeinehvand, Mohammad M.; Uddin, Shah M.; Benzina, Abderazak; Rothan, Hussin A.; Yusof, Rohana; Koole, Leo H.; Madou, Marc J.; Djordjevic, Ivan; Ibrahim, Fatimah

    2015-11-01

    The application of microfluidic devices in diagnostic systems is well-established in contemporary research. Large specific surface area of microspheres, on the other hand, has secured an important position for their use in bioanalytical assays. Herein, we report a combination of microspheres and microfluidic disk in a unique hybrid platform for highly sensitive and selective detection of dengue virus. Surface engineered polymethacrylate microspheres with carefully designed functional groups facilitate biorecognition in a multitude manner. In order to maximize the utility of the microspheres’ specific surface area in biomolecular interaction, the microfluidic disk was equipped with a micromixing system. The mixing mechanism (microballoon mixing) enhances the number of molecular encounters between spheres and target analyte by accessing the entire sample volume more effectively, which subsequently results in signal amplification. Significant reduction of incubation time along with considerable lower detection limits were the prime motivations for the integration of microspheres inside the microfluidic disk. Lengthy incubations of routine analytical assays were reduced from 2 hours to 5 minutes while developed system successfully detected a few units of dengue virus. Obtained results make this hybrid microsphere-microfluidic approach to dengue detection a promising avenue for early detection of this fatal illness.

  10. Synthesis of phase-pure U2N3 microspheres and its decomposition into UN.

    Science.gov (United States)

    Silva, Chinthaka M; Hunt, Rodney D; Snead, Lance L; Terrani, Kurt A

    2015-01-05

    Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. However, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U2N3) were synthesized by nitridation of UO2+C microspheres at a few different temperatures. Resulting microspheres were of low-density U2N3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U2N3. Average grain sizes of both U2N3 and UN varied in a range of 1-2.5 μm. These also had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.

  11. Hydrogen transport and storage in engineered microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G. [Lawrence Livermore National Lab., CA (United States); Hendricks, C. [W.J. Schafer Associates, Livermore, CA (United States)

    1996-10-01

    This project is a collaboration between Lawrence Livermore National Laboratory (LLNL) and W.J. Schafer Associates (WJSA). The authors plan to experimentally verify the performance characteristics of engineered glass microspheres that are relevant to the storage and transport of hydrogen for energy applications. They will identify the specific advantages of hydrogen transport by microspheres, analyze the infrastructure implications and requirements, and experimentally measure their performance characteristics in realistic, bulk storage situations.

  12. Coacervate microspheres as carriers of recombinant adenoviruses.

    Science.gov (United States)

    Kalyanasundaram, S; Feinstein, S; Nicholson, J P; Leong, K W; Garver, R I

    1999-01-01

    The therapeutic utility of recombinant adenoviruses (rAds) is limited in part by difficulties in directing the viruses to specific sites and by the requirement for bolus administration, both of which limit the efficiency of target tissue infection. As a first step toward overcoming these limitations, rAds were encapsulated in coacervate microspheres comprised of gelatin and alginate followed by stabilization with calcium ions. Ultrastructural evaluation showed that the microspheres formed in this manner were 0.8-10 microM in diameter, with viruses evenly distributed. The microspheres achieved a sustained release of adenovirus with a nominal loss of bioactivity. The pattern of release and the total amount of virus released was modified by changes in microsphere formulation. Administration of the adenovirus-containing microspheres to human tumor nodules engrafted in mice showed that the viral transgene was transferred to the tumor cells. It is concluded that coacervate microspheres can be used to encapsulate bioactive rAd and release it in a time-dependent manner.

  13. Demonstration of Microsphere Insulation in Cryogenic Vessels

    Science.gov (United States)

    Baumgartner, R. G.; Myers, E. A.; Fesmire, J. E.; Morris, D. L.; Sokalski, E. R.

    2006-04-01

    While microspheres have been recognized as a legitimate insulation material for decades, actual use in full-scale cryogenic storage tanks has not been demonstrated until now. The performance and life-cycle-cost advantages previously predicted have now been proven. Most bulk cryogenic storage tanks are insulated with either multilayer insulation (MLI) or perlite. Microsphere insulation, consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. These properties were proven during recent field testing of two 22,700-L (6,000-gallon) liquid nitrogen tanks, one insulated with microsphere insulation and the other with perlite. Normal evaporation rates (NER) for both tanks were monitored with precision test equipment and insulation levels within the tanks were observed through view ports as an indication of insulation compaction. Specific industrial applications were evaluated based on the test results and beneficial properties of microsphere insulation. Over-the-road trailers previously insulated with perlite will benefit not only from the reduced heat leak, but also the reduced mass of microsphere insulation. Economic assessments for microsphere-insulated cryogenic vessels including life-cycle cost are also presented.

  14. Evaluation of glibenclamide microspheres for sustained release

    Directory of Open Access Journals (Sweden)

    Kambham Venkateswarlu

    2017-04-01

    Full Text Available Context: Sustained release drug delivery systems are more preferred than the conventional drug delivery systems due to its enhanced bioavailability and patient compliance. Earlier studies reported on glibenclamide (GBCM were not clear and hence, the step has been taken to explore the sustained release drug delivery system of GBCM. Aims: To evaluate the sustained release microspheres obtained of GBCM. Methods: Microspheres were prepared by ionic gelation method using the polymers like Eudragit RS 100 and xanthan gum. Polymers can sustain the drug release from microspheres. The prepared microspheres were subjected to micromeritic studies like Carr’s index, Hausner’s ratio and angle of repose. Results: Micromeritic studies confirmed that the microspheres possessing acceptable flow properties. It was observed from the in vitro release studies, formulations F8 and F9 showed sustained drug release for desired time of 12 h and when compared to F9, formulation F8 showed maximum drug release for 12 h. Conclusions: Results confirmed the formulation F8 consist of the polymers such as Eudragit RS 100 about 150 mg and xanthan gum about 100 mg showed desired sustained release of 12 h with 96.07% and kinetic studies confirmed that the release from microspheres followed non-Fickian diffusion mechanism. Due to its sustained release property, it could enhance the bioavailability of drug thereby improves the patient compliance and expect better treatment than conventional dosage forms.

  15. Controllable preparation of hierarchically core–shell structure NiO/C microspheres for non-enzymatic glucose sensor

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Zhenzhen; Yin, Haoyong; Nie, Qiulin, E-mail: nieqiulin@hdu.edu.cn

    2015-05-25

    Highlights: • Hierarchically core–shell structure NiO/C microspheres were prepared. • The NiO/C microspheres were obtained via layer-by-layer assembly methods. • The NiO/C sensor shows excellent performance in glucose detection. • Good stability and anti-interference were also obtained on the NiO/C sensor. - Abstract: Hierarchically core–shell structure NiO/C microspheres were controllably fabricated with a facile hydrothermal method via layer-by-layer assembly. The single-/double-/triple-/quadri-shelled NiO/C microspheres were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX). The results showed that the NiO/C composites are flower-like hierarchically structured microspheres composed of the interconnecting porous nanoplates with the thickness of about 50 nm. Every nanoplate is assembled by NiO nanoparticles with diameter about 10 nm. All the multi-shelled NiO/C microspheres show high electro-catalytic activity toward the oxidation of glucose. The double-shelled NiO/C glucose sensor exhibits the best performance with a much wider linear range of 2 μM–1.279 mM, higher sensitivity of 30.19 mA mM{sup −1} cm{sup −2} and lower detection limit of 2 μM. Importantly, long-term stability and favorable anti-interference were obtained thanks to the hierarchically core–shell structure.

  16. Methods for Large-scale and Long-term Animal Cell Culture with Porous Microcarriers%用多孔微载体大规模长期培养动物细胞的方法

    Institute of Scientific and Technical Information of China (English)

    胡显文; 肖成祖; 高丽华; 李佐虎

    2001-01-01

    Long-term and large-scale and high-density animal cell culture is critical in biopharmaceutical industry. A recombinant Chinese hamster ovary cell line which secrets prourokinase Pro-UK was cultivated continuously on porous microcarriers in pilot-scale bioreactors. The methods of long-term and large-scale animal cell culture were introduced in this paper.%长期大规模高密度动物细胞培养是生物制药产业中的关键技术,文中介绍了利用多孔微载体在中试规模生物反应器中长期大规模连续培养分泌尿激酶原的DNA重组中国仓鼠卵巢细胞(rCHO)的方法。

  17. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  18. Microsphere-chain waveguides: Focusing and transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Kenneth W., E-mail: kallen62@uncc.edu; Astratov, Vasily N., E-mail: astratov@uncc.edu [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Darafsheh, Arash; Abolmaali, Farzaneh [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Mojaverian, Neda; Limberopoulos, Nicholaos I. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Lupu, Anatole [Institut d' Electronique Fondamentale, UMR 8622 CNRS, Universite Paris-Sud XI, 91405 Orsay (France)

    2014-07-14

    It is shown that the focusing properties of polystyrene microsphere-chain waveguides (MCWs) formed by sufficiently large spheres (D ≥ 20λ, where D is the sphere diameter and λ is the wavelength of light) scale with the sphere diameter as predicted by geometrical optics. However, this scaling behavior does not hold for mesoscale MCWs with D ≤ 10λ resulting in a periodical focusing with gradually reducing beam waists and in extremely small propagation losses. The observed effects are related to properties of nanojet-induced and periodically focused modes in such structures. The results can be used for developing focusing microprobes, laser scalpels, and polarization filters.

  19. Formation of superhydrophobic microspheres of poly(vinylidene fluoride- hexafluoropropylene)/graphene composite via gelation.

    Science.gov (United States)

    Zhang, Li; Zha, Dao-an; Du, Tingting; Mei, Shilin; Shi, Zujin; Jin, Zhaoxia

    2011-07-19

    We report on the spontaneous formation of superhydrophobic poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/graphene composite microspheres with uniform size via gelation. When the suspension of PVDF-HFP/graphene (0.25 wt. % with respect to PVDF-HFP) in DMF adsorbs water vapor, it changes to a hybrid gel. A dried porous gel is obtained after solvent exchange and freeze drying. Morphology characterization shows that this hybrid gel is composed of PVDF-HFP/graphene microspheres with a diameter of 8-10 μm. In contrast, PVDF-HFP solution gives rise to a cellular microstructure following the same experimental procedures. We further elucidate the formation mechanism on the basis of the characterization by freeze fracture transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry characterizations. Furthermore, contact angle measurements of water on PVDF-HFP/graphene indicates that the hydrophobic nature of PVDF-HFP combined with the micro/nanoscale hierarchical texture creates a superhydrophobic surface. Such superhydrophobic microspheres may have potential applications as water-repellent catalyst-supporting materials.

  20. Hierarchical bismuth phosphate microspheres with high photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Lizhai; Wei, Tian; Lin, Nan; Yu, Haiyun [Anhui University of Technology, Ma' anshan (China). Key Laboratory of Materials Science and Processing of Anhui Province

    2016-05-15

    Hierarchical bismuth phosphate microspheres have been prepared by a simple hydrothermal process with polyvinyl pyrrolidone. Scanning electron microscopy observations show that the hierarchical bismuth phosphate microspheres consist of nanosheets with a thickness of about 30 nm. The diameter of the microspheres is about 1 - 3 μm. X-ray diffraction analysis shows that the microspheres are comprised of triclinic Bi{sub 23}P{sub 4}O{sub 44.5} phase. The formation of the hierarchical microspheres depends on polyvinyl pyrrolidone concentration, hydrothermal temperature and reaction time. Gentian violet acts as the pollutant model for investigating the photocatalytic activity of the hierarchical bismuth phosphate microspheres under ultraviolet-visible light irradiation. Irradiation time, dosage of the hierarchical microspheres and initial gentian violet concentration on the photocatalytic efficiency are also discussed. The hierarchical bismuth phosphate microspheres show good photocatalytic performance for gentian violet removal in aqueous solution.

  1. Release of a Wound-Healing Agent from PLGA Microspheres in a Thermosensitive Gel

    Directory of Open Access Journals (Sweden)

    H. A. Machado

    2013-01-01

    Full Text Available The purpose of this research was to develop a topical microsphere delivery system in a thermosensitive 20% poloxamer 407 gel (Pluronic F127 to control release of KSL-W, a cationic antimicrobial decapeptide, for a period of 4–7 days for potential application in combat related injuries. KSL-W loaded microsphere formulations were prepared by a solvent extraction-evaporation method (water-oil-water, with poly (D,L-lactic-co-glycolic acid (PLGA (50 : 50, low-weight, and hydrophilic end as the polymeric system. After optimization of the process, three formulations (A, B, and C were prepared with different organic to water ratio of the primary emulsion while maintaining other components and manufacturing parameters constant. Formulations were characterized for surface morphology, porous nature, drug loading, in vitro drug release, and antimicrobial activity. Microspheres containing 20% peptide with porous surfaces and internal structure were prepared in satisfactory yields and in sizes varying from 25 to 50 μm. Gels of 20% Pluronic F127, which were liquid at or below 24.6°C and formed transparent films at body temperature, were used as carriers for the microspheres. Rheological studies showed a gelation temperature of 24.6°C for the 20% Pluronic F127 gel alone. Gelation temperature and viscosity of formulations A, B, and C as a function of temperature were very close to those of the carrier. A Franz diffusion cell system was used to study the release of peptide from the microspheres suspended in both, phosphate-buffered saline (PBS and a 20% Pluronic F127 gel. In vitro release of greater than 50% peptide was found in all formulations in both PBS and the gel, and in one formulation there was a release of 75% in both PBS and the gel. Fractions collected from the release process were also tested for bactericidal activity against Staphylococcus epidermidis using the broth microdilution method and found to provide effective antimicrobial activity

  2. Hierarchical flower-like nickel(II) oxide microspheres with high adsorption capacity of Congo red in water.

    Science.gov (United States)

    Zheng, Yingqiu; Zhu, Bicheng; Chen, Hua; You, Wei; Jiang, Chuanjia; Yu, Jiaguo

    2017-10-15

    Monodispersed hierarchical flower-like nickel(II) oxide (NiO) microspheres were fabricated by a facile solvothermal reaction with the assistance of ethanolamine and a subsequent calcination process. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms, zeta potential measurement and Fourier transform infrared spectroscopy. Flower-like nickel(II) hydroxide microspheres with uniform diameters of approximate 6.3μm were obtained after the solvothermal reaction. After heat treatment at 350°C, the crystal phase transformed to NiO, but the hierarchical porous structure was maintained. The as-prepared microspheres exhibited outstanding performance for the adsorption of Congo red (CR), an anionic organic dye, from aqueous solution at circumneutral pH. The pseudo-second-order model can make a good description of the adsorption kinetics, while Langmuir model could well express the adsorption isotherms, with calculated maximum CR adsorption capacity of 534.8 and 384.6mgg(-1), respectively, for NiO and Ni(OH)2. The adsorption mechanism of CR onto the as-synthesized samples can be mainly attributed to electrostatic interaction between the positively charged sample surface and the anionic CR molecules. The as-prepared NiO microspheres are a promising adsorbent for CR removal in water treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Release of macromolecules from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Hydrophilic microspheres based on albumin-heparin conjugates have been prepared as a macromolecular delivery system. The soluble albumin-heparin conjugate was synthesized and crosslinked in a water-in-oil emulsion with glutaraldehyde to form microspheres in the same manner as for albumin microsphere

  4. Rheological Behavior of an Epoxy Resin with Hollow Glass Microspheres

    Science.gov (United States)

    Costa, Cleber C.; Calado, Verônica; Tavares, Frederico W.

    2008-07-01

    An investigation was carried out on the rheological behavior of a TET/DGEBA epoxy formulations with hollow glass microspheres using different types and different volume fractions of microspheres to manufacture composites. It was proposed an equation to describe viscosity as a function of microsphere volume fracion. The fit to the experimental data was excellent.

  5. Preparation of microstructured hydroxyapatite microspheres using oil in water emulsions

    Indian Academy of Sciences (India)

    T S Pradeesh; M C Sunny; H K Varma; P Ramesh

    2005-08-01

    Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal debinding and sintering at 1150°C for 3 h to obtain HAP microspheres. Each microsphere of 100–1000 m was in turn composed of spherical hydroxyapatite granules of 2–15 m size which were obtained by spray drying the precipitated HAP. The parameters such as percentage of initial HAP loading, type of stabilizer, concentration of stabilizer, stirring speed and temperature of microsphere preparation were varied to study their effect on the particle size and geometry of the microspheres obtained. It was observed that these parameters do have an effect on the size and shape of the microspheres obtained, which in turn will affect the sintered HAP microstructure. Of the three stabilizers used viz. polyoxyethylene(20) sorbitan monopalmitate (Tween-40), sodium laurate and polyvinyl alcohol (PVA), only PVA with a concentration not less than 0.1 wt% showed controlled stabilization of HAP granules resulting in spherical microspheres of required size. Morphologically better spherical microspheres were obtained at 20°C. Increasing the stirring speed produced smaller microspheres. Smaller microspheres having size < 50 m were obtained at a stirring speed of 1500 ± 50 rpm. A gradual decrease in pore size was observed in the sintered microspheres with increase in HAP loading.

  6. Fabricating solid carbon porous electrodes from powders

    Energy Technology Data Exchange (ETDEWEB)

    Kaschmitter, James L. (Pleasanton, CA); Tran, Tri D. (Livermore, CA); Feikert, John H. (Livermore, CA); Mayer, Steven T. (San Leandro, CA)

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (<50 m.sup.2 /gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  7. Fabricating solid carbon porous electrodes from powders

    Energy Technology Data Exchange (ETDEWEB)

    Kaschmitter, J.L.; Tran, T.D.; Feikert, J.H.; Mayer, S.T.

    1997-06-10

    Fabrication is described for conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive deionization, and waste treatment. Electrodes fabricated from low surface area (<50 m{sup 2}/gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon composites with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to high surface area carbons, fuel cell electrodes can be produced. 1 fig.

  8. Repeated Microsphere Delivery for Serial Measurement of Regional Blood Perfusion in the Chronically Instrumented, Conscious Canine

    Science.gov (United States)

    Bartoli, Carlo R.; Okabe, Kazunori; Akiyama, Ichiro; Coull, Brent; Godleski, John J.

    2008-01-01

    INTRODUCTION For chronic, repeated hemodynamic studies in conscious dogs, we designed and tested a chronically instrumented canine, microsphere delivery model. The goals of this study were to investigate the accuracy of repeated estimations of blood perfusion using fluorescent-labeled microspheres and to develop and validate a chronic preparation that permits consecutive estimations in the same conscious animal over an extended protocol. METHODS Via thoracotomy, 9 dogs were instrumented with left atrial appendage and aortic vascular access catheters connected to subcutaneous vascular access ports (VAPs). Four animals received 7 serial injections of 1.6 million 15μm microspheres (total: 11.2 million), and five animals received 8 serial injections of 2.25 million microspheres (total: 18 million) over the course of 11 or 18 weeks. RESULTS All catheters have remained bidirectionally patent during protocol for 14.9±0.8 (Mean±SEM) weeks. Sphere accumulation did not significantly alter global myocardial (p=0.69, p=0.25), renal (p=0.92, p=0.12), hepatic (p=0.84, p=0.32), or splenic (p=0.33, p=0.70) blood perfusion in either set of animals. CONCLUSIONS Catheters remained bidirectionally patent for months, did not interfere with the hemodynamic responses of the preparation, and allowed repeat percutaneous injection of microspheres and withdrawal of reference arterial blood from within conscious canines. Eight serial injections totaling 18 million microspheres over 18 weeks did not alter regional myocardial, hepatic, renal, or splenic blood flow. This dependable, chronic, percutaneous arterial access preparation provides a means for examining acute and long-term effects of pathophysiological, pharmaceutical, and environmental influences on regional arterial blood perfusion in conscious, large animals. PMID:17632127

  9. Synthesis of biodegradable polymer-mesoporous silica composite microspheres for DNA prime-protein boost vaccination.

    Science.gov (United States)

    Ho, Jenny; Huang, Yi; Danquah, Michael K; Wang, Huanting; Forde, Gareth M

    2010-03-18

    DNA vaccines or proteins are capable of inducing specific immunity; however, the translation to the clinic has generally been problematic, primarily due to the reduced magnitude of immune response and poor pharmacokinetics. Herein we demonstrate a composite microsphere formulation, composed of mesoporous silica spheres (MPS) and poly(D,L-lactide-co-glycolide) (PLGA), enables the controlled delivery of a prime-boost vaccine via the encapsulation of plasmid DNA (pDNA) and protein in different compartments. Method with modified dual-concentric-feeding needles attached to a 40 kHz ultrasonic atomizer was studied. These needles focus the flow of two different solutions, which passed through the ultrasonic atomizer. The process synthesis parameters, which are important to the scale-up of composite microspheres, were also studied. These parameters include polymer concentration, feed flowrate, and volumetric ratio of polymer and pDNA-PEI/MPS-BSA. This fabrication technique produced composite microspheres with mean D[4,3] ranging from 6 to 34 microm, depending upon the microsphere preparation. The resultant physical morphology of composite microspheres was largely influenced by the volumetric ratio of pDNA-PEI/MPS-BSA to polymer, and this was due to the precipitation of MPS at the surface of the microspheres. The encapsulation efficiencies were predominantly in the range of 93-98% for pDNA and 46-68% for MPS. In the in vitro studies, the pDNA and protein showed different release kinetics in a 40 day time frame. The dual-concentric-feeding in ultrasonic atomization was shown to have excellent reproducibility. It was concluded that this fabrication technique is an effective method to prepare formulations containing a heterologous prime-boost vaccine in a single delivery system.

  10. Computational dynamics of acoustically driven microsphere systems.

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  11. Amine Functionalized Porous Network

    KAUST Repository

    Eddaoudi, Mohamed

    2015-05-28

    Amine groups can be introduced in porous materials by a direct (one pot) or post-synthetic modification (PSM) process on aldehyde groups, and the resulting porous materials have increased gas affinity.

  12. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  13. Biosensing by WGM Microspherical Resonators

    Science.gov (United States)

    Righini, Giancarlo C.; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  14. Mathematical Model of Porous Medium Dynamics

    Science.gov (United States)

    Gerschuk, Peotr; Sapozhnikov, Anatoly

    1999-06-01

    Semiempirical model describing porous material strains under pulse mechanical and thermal loadings is proposed. Porous medium is considered as continuous one but with special form of pressure dependence upon strain. This model takes into account principal features of porous materials behavior which can be observed when the material is strained in dynamic and static experiments ( non-reversibility of large strains, nonconvexity of loading curve). Elastoplastic properties of porous medium, its damages when it is strained and dynamic fracture are also taken into account. Dispersion of unidirectional motion caused by medium heterogeneity (porousness) is taken into acount by introducing the physical viscosity depending upon pores size. It is supposed that at every moment of time pores are in equilibrium with pressure i.e. kinetic of pores collapse is not taken into account. The model is presented by the system of differential equations connecting pressure and energy of porous medium with its strain. These equations close system of equations of motion and continuity which then is integrated numerically. The proposed model has been tested on carbon materials and porous copper . Results of calculation of these materials shock compressing are in satisfactory agreement with experimental data. Results of calculation of thin plate with porous copper layer collision are given as an illustration.

  15. Improving photoprotection: 4-methylbenzylidene camphor microspheres.

    Science.gov (United States)

    Centini, Marisanna; Miraglia, Giovanna; Quaranta, Valeria; Buonocore, Anna; Anselmi, Cecilia

    2014-05-22

    Abstract We propose a new approach for photoprotection. 4-Methylbenzylidene camphor (4-MBC), one of the most widely used UV filters, was encapsulated in microspheres, with a view to overcoming problems (percutaneous absorption, photodegradation and lack of lasting effect) arising with organic sunscreens, and to achieve safe photoprotection. We focused on this filter in the light of the Cosmetics Europe opinion concerning its possible effects on the thyroid gland. Microspheres were prepared by emulsification-solvent evaporation, using different amounts of 4-MBC and characterized for morphology, encapsulation efficiency and particle size. The particles were then mixed in O/W emulsions. The in vitro sun protection factors, in vitro release and photostability were investigated and compared with emulsions containing the free sunscreen. The new microspheres offer good morphology and loading (up to 40%), and the same photoprotection as the free filter while at the same time protecting it from photodegradation. The systems also give a slower release from the emulsions.

  16. Removal of radioactive contaminants by polymeric microspheres.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2016-11-01

    Radionuclide removal from radioactive liquid waste by adsorption on polymeric microspheres is the latest application of polymers in waste management. Polymeric microspheres have significant immobilization capacity for ionic substances. A laboratory study was carried out by using poly(N-isopropylacrylamide) for encapsulation of radionuclide in the liquid radioactive waste. There are numbers of advantages to use an encapsulation technology in radioactive waste management. Results show that polymerization step of radionuclide increases integrity of solidified waste form. Test results showed that adding the appropriate polymer into the liquid waste at an appropriate pH and temperature level, radionuclide was encapsulated into polymer. This technology may provide barriers between hazardous radioactive ions and the environment. By this method, solidification techniques became easier and safer in nuclear waste management. By using polymer microspheres as dust form, contamination risks were decreased in the nuclear industry and radioactive waste operations.

  17. A biosensor for urea from succinimide-modified acrylic microspheres based on reflectance transduction.

    Science.gov (United States)

    Ulianas, Alizar; Heng, Lee Yook; Ahmad, Musa

    2011-01-01

    New acrylic microspheres were synthesised by photopolymerisation where the succinimide functional group was incorporated during the microsphere preparation. An optical biosensor for urea based on reflectance transduction with a large linear response range to urea was successfully developed using this material. The biosensor utilized succinimide-modified acrylic microspheres immobilized with a Nile blue chromoionophore (ETH 5294) for optical detection and urease enzyme was immobilized on the surface of the microspheres via the succinimide groups. No leaching of the enzyme or chromoionophore was observed. Hydrolysis of the urea by urease changes the pH and leads to a color change of the immobilized chromoionophore. When the color change was monitored by reflectance spectrophotometry, the linear response range of the biosensor to urea was from 0.01 to 1,000 mM (R2 = 0.97) with a limit of detection of 9.97 μM. The biosensor response showed good reproducibility (relative standard deviation = 1.43%, n = 5) with no interference by major cations such as Na+, K+, NH4+ and Mg2+. The use of reflectance as a transduction method led to a large linear response range that is better than that of many urea biosensors based on other optical transduction methods.

  18. A Biosensor for Urea from Succinimide-Modified Acrylic Microspheres Based on Reflectance Transduction

    Directory of Open Access Journals (Sweden)

    Musa Ahmad

    2011-08-01

    Full Text Available New acrylic microspheres were synthesised by photopolymerisation where the succinimide functional group was incorporated during the microsphere preparation. An optical biosensor for urea based on reflectance transduction with a large linear response range to urea was successfully developed using this material. The biosensor utilized succinimide-modified acrylic microspheres immobilized with a Nile blue chromoionophore (ETH 5294 for optical detection and urease enzyme was immobilized on the surface of the microspheres via the succinimide groups. No leaching of the enzyme or chromoionophore was observed. Hydrolysis of the urea by urease changes the pH and leads to a color change of the immobilized chromoionophore. When the color change was monitored by reflectance spectrophotometry, the linear response range of the biosensor to urea was from 0.01 to 1,000 mM (R2 = 0.97 with a limit of detection of 9.97 mM. The biosensor response showed good reproducibility (relative standard deviation = 1.43%, n = 5 with no interference by major cations such as Na+, K+, NH4+ and Mg2+. The use of reflectance as a transduction method led to a large linear response range that is better than that of many urea biosensors based on other optical transduction methods.

  19. A microsphere suspension model of metamaterial fluids

    Directory of Open Access Journals (Sweden)

    Qian Duan

    2017-05-01

    Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.

  20. Stabilization and immune response of HBsAg encapsulated within poly(lactic-co-glycolic acid) microspheres using HSA as a stabilizer.

    Science.gov (United States)

    Xu, Wenjuan; He, Jintian; Wu, Guanghao; Xiong, Fangfang; Du, Huijuan; Wang, Gaizhen

    2015-12-30

    The aim of this study was to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres containing hepatitis B virus surface antigen (HBsAg) using human serum albumin (HSA) as a stabilizer. Lyophilization and emulsification of HBsAg solution with dichloromethane caused a considerable loss of HBsAg antigenicity. Thus, the effects of HSA and trehalose on HBsAg recovery during lyophilization and emulsification were investigated. Adding HSA to HBsAg solutions significantly improved antigen recovery to >90% during lyophilization and emulsification. The effects of co-encapsulated HSA on the characteristics of the PLGA microspheres and stability of HBsAg released from the microspheres were also investigated. The in vitro release test showed that HBsAg was released from the PLGA microspheres continuously over seventy days. A large amount of released HBsAg was inactive without co-encapsulation of HSA. On the contrary, with HSA co-encapsulation, the released HBsAg retained approximately 90% of its antigenicity. The single injection of the HBsAg-HSA-loaded PLGA microspheres in rats resulted in higher anti-HBsAg IgG and Th1 cytokine levels than the single injection of the HBsAg-loaded microspheres or two injections of the conventional aluminum-adjuvanted HBsAg vaccine. Based on these findings, the HBsAg-HSA-loaded PLGA microspheres could be an effective carrier for HBsAg and form a promising depot system.

  1. Preparation of Micron-size Functional Fluorescent Microspheres

    Institute of Scientific and Technical Information of China (English)

    WANG Di-qiang; LIU Bai-ling; LI He; HU Jie

    2004-01-01

    As a kind of special functional microspheres, fluorescent polymer microspheres could be used in cell label and separation, blood flow assay, flow cytometer marking, chemical reaction assay,and in analyst of the transform and diffusion of particles in soil 1. However, one of the most important applications of fluorescent microspheres is in the high-throughput screening of drugs (HTS) 2. Through affinity interaction, radioactive ligands (latent drugs) are bound to fluorescent microspheres covered by receptor, and luminescence is produced by radioactivity, so ligands can be assayed and screened.In this study, we developed a technique for preparing micron-size fluorescent microspheres with different functional groups. The methods included the synthesis of micron-size polystyrene microspheres through the dispersion polymerization of styrene in different media such as ethanol,ethanol-water, and isopropanol; the functional polystyrene microspheres were prepared by introduction of functional monomers into the reaction system of styrene; the functional fluorescent microspheres were obtained by the way of dying functional microspheres in the fluorescent material's ethanol solvent.The average diameter of microspheres was in the range of 1~10 μm, and the distribution was normal distribution. The functional groups included -OH, -CHO, -COOH, -CONH2, and SO3H. The absorbing spectrum and exciting spectrum were tested, the results showed that the maximal absorbance of fluorescent microsphere was near 306.5 nm, and its maximal excitation was near 362 nm. The excitation spectrum of fluorescent material (DPO) and fluorescent microspheres were shown in figure 1, and it indicated that the developed fluorescent microspheres showed the same excitation behavior like DPO, which related to the fluorescent microspheres had stable luminescence property.

  2. Tailored Porous Materials

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  3. Porous and Nanoporous Semiconductors and Emerging Applications

    Directory of Open Access Journals (Sweden)

    Helmut Föll

    2006-01-01

    Full Text Available Pores in single-crystalline semiconductors can be produced in a wide range of geometries and morphologies, including the “nanometer” regime. Porous semiconductors may have properties completely different from the bulk, and metamaterials with, for example, optical properties not encountered in natural materials are emerging. Possible applications of porous semiconductors include various novel sensors, but also more “exotic” uses as, for example, high explosives or electrodes for micro-fuel cells. The paper briefly reviews pore formation (including more applied aspects of large area etching, properties of porous semiconductors, and emerging applications.

  4. Thermal behavior of a porous electric heater

    Energy Technology Data Exchange (ETDEWEB)

    Naji, M.; Al-Nimr, M.A. [Jordan University of Science and Technology, Irbid (Jordan). Dept. of Mechanical Engineering

    2002-03-01

    The performance of a proposed porous electric heater is investigated. The porous heater exchanges heat with the working fluid through its large volumetric surface area. As a result, it produces lower surface temperature as compared with the conventional heater for the same imposed heating power. Two mathematical models are presented to describe the thermal behavior of both heaters. Axial diffusion is included in the governing equation of the solid conventional heater. The predictions of both models are compared at different operating conditions where it is found that porous heaters have much better thermal performance than the conventional heaters. (author)

  5. THE COMBUSTION PERFORMANCE OF MEDIUM DENSITY FIBERBOARD TREATED WITH FIRE RETARDANT MICROSPHERES

    Directory of Open Access Journals (Sweden)

    Lichao Sun,

    2011-12-01

    Full Text Available Fire retardant particles (guanylurea phosphate and boric acid with a morphological characteristic of large crystal or fine microsphere, were respectively applied to wood fibers to make medium density fiberboard (MDF. The effects of particle size of the fire retardant on the combustion performance of the resulting MDF samples were determined using a thermogravimetric (TG analyzer and cone calorimeter (CONE. The scanning electron microscopy and laser particle size analysis showed that the microspheric particles of fire retardant had a mean size of approximately 20 µm, which was smaller than the crystal (260 um. Incorporation of the fire retardant either in the crystal or microsphere shape reduced the weight loss of the resulting MDF, as evidenced by the TG analysis and the CONE test; the release rate and total amount of both the heat and smoke were apparently inhibited as compared to the untreated MDF samples. Treatments caused an increase in both the ignition time and charring ratio of the MDF. Compared with the fire retardant crystals, the fine microspheric particles exhibited greater ability in inhibiting the release of heat and smoke through the combustion processes.

  6. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    Science.gov (United States)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  7. Bilayer Tablet via Microsphere: A Review

    Directory of Open Access Journals (Sweden)

    Piyushkumar Vinubhai Gundaraniya

    2013-01-01

    Full Text Available The aim of the present work is to develop bilayer tablets containing sustained release microspheres as one layer and immediate release as another layer. The proposed dosage form is intended to decrease the dosing frequency and the combined administration of an anti-diabetic agent. Several pharmaceutical companies are currently developing bi-layer tablets, for a variety of reasons: patent extension, therapeutic, marketing to name a few. To reduce capital investment, quite often existing but modified tablet presses are used to develop and produce such tablets. One such approach is using microspheres as carriers for drugs also known as micro particles. It is the reliable means to deliver the drug to the target site with specificity, if modified, and to maintain the desired concentration at the site of interest. Microspheres received much attention not only for prolonged release, but also for targeting of anti-diabetic drugs. Bilayer tablet via microsphere is new era for the successful development of controlled release formulation along with various features to provide a way of successful drug delivery system. Especially when in addition high production output is required. An attempt has been made in this review article to introduce the society to the current technological developments in bilayer and floating drug delivery system.

  8. Tumor Vaccination With Cytokine-Loaded Microspheres

    Science.gov (United States)

    2005-12-01

    buffer (1% hydroxypropylmethylcellulose [DOW Co., Midlands, MI, USA] and 1% Pluronic F127 [Sigma] in phosphate-buffered saline [PBS], pH 7.2). Control mice...hydration buffer (1% hydroxypropylmethylcellulose (Dow) and 1% Pluronic F-127 (Sigma- Aldrich) in PBS, pH 7.2). Control mice received blank microspheres

  9. Arabinoxylan Microspheres: Structural and Textural Characteristics

    Directory of Open Access Journals (Sweden)

    Yolanda López-Franco

    2013-04-01

    Full Text Available The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX microspheres. The laccase-induced cross-linking process was monitored by storage (G' and loss (G'' moduli changes in a 4% (w/v MBAX solution. The G' and G'' values at the plateau region were 215 and 4 Pa, respectively. After gelation, the content of ferulic acid dimers decreased from 0.135 to 0.03 µg/mg MBAX, suggesting the formation of ferulated structures unreleased by mild alkaline hydrolysis. MBAX microspheres presented an average diameter of 531 µm and a swelling ratio value (q of 18 g water/g MBAX. The structural parameters of MBAX microspheres were calculated from equilibrium swelling experiments, presenting an average mesh size of 52 nm. Microstructure and textural properties of dried MBAX microspheres were studied by scanning electron microscopy and nitrogen adsorption/desorption isotherms, respectively, showing a heterogeneous mesoporous and macroporous structure throughout the network.

  10. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of silicone droplets in a continuous aqueous phase. The commonly used PDMS elastomer, Sylgard 184 from Dow Corning, is used as the dispersed phase. PDMS is polymerized and cross-linked by reacting vinyl...

  11. Superhydrophobic Porous Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Paolo NENZI

    2011-12-01

    Full Text Available In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet etch to produce pores with controlled size and distribution and coated with a silane hydrophobic layer. Surface morphology is characterized by means of scanning electron microscope images. Large contact angles are observed on such surfaces and the results are compared with classical wetting models (Cassie and Wenzel suggesting a mixed Wenzel-Cassie behavior. The presented technique represents a cost-effective means for friction reduction in microfluidic applications, such as lab-on-a-chip.

  12. The performance of porous electric heaters

    Energy Technology Data Exchange (ETDEWEB)

    Al-Nimr, M.A.; Naji, M.

    2003-03-01

    The performance of a proposed porous electric heater is investigated. The porous heater exchanges heat with the working fluid through its large volumetric surface area. As a result, it produces lower surface temperature as compared with the conventional heater for the same imposed heating power. Two mathematical models are presented to describe the thermal behavior of both heaters and the predictions of both models are compared at different operating conditions. (author)

  13. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    Science.gov (United States)

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

  14. Subcritical CO{sub 2} sintering of microspheres of different polymeric materials to fabricate scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Bhamidipati, Manjari; Sridharan, BanuPriya [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Scurto, Aaron M. [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS (United States); Detamore, Michael S., E-mail: detamore@ku.edu [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS (United States)

    2013-12-01

    The aim of this study was to use CO{sub 2} at sub-critical pressures as a tool to sinter 3D, macroporous, microsphere-based scaffolds for bone and cartilage tissue engineering. Porous scaffolds composed of ∼ 200 μm microspheres of either poly(lactic-co-glycolic acid) (PLGA) or polycaprolactone (PCL) were prepared using dense phase CO{sub 2} sintering, which were seeded with rat bone marrow mesenchymal stromal cells (rBMSCs), and exposed to either osteogenic (PLGA, PCL) or chondrogenic (PLGA) conditions for 6 weeks. Under osteogenic conditions, the PLGA constructs produced over an order of magnitude more calcium than the PCL constructs, whereas the PCL constructs had far superior mechanical and structural integrity (125 times stiffer than PLGA constructs) at week 6, along with twice the cell content of the PLGA constructs. Chondrogenic cell performance was limited in PLGA constructs, perhaps as a result of the polymer degradation rate being too high. The current study represents the first long-term culture of CO{sub 2}-sintered microsphere-based scaffolds, and has established important thermodynamic differences in sintering between the selected formulations of PLGA and PCL, with the former requiring adjustment of pressure only, and the latter requiring the adjustment of both pressure and temperature. Based on more straightforward sintering conditions and more favorable cell performance, PLGA may be the material of choice for microspheres in a CO{sub 2} sintering application, although a different PLGA formulation with the encapsulation of growth factors, extracellular matrix-derived nanoparticles, and/or buffers in the microspheres may be advantageous for achieving a more superior cell performance than observed here. - Highlights: • The first long-term culture of CO{sub 2}-sintered microsphere-based scaffolds. • Established important thermodynamic differences between sintering PLGA and PCL. • PCL sintering with CO{sub 2} required manipulation of both

  15. PLGA microspheres encapsulating siRNA.

    Science.gov (United States)

    De Rosa, Giuseppe; Salzano, Giuseppina

    2015-01-01

    The therapeutic use of small interfering RNA (siRNA) represents a new and powerful approach to suppress the expression of pathologically genes. However, biopharmaceutical drawbacks, such as short half-life, poor cellular uptake, and unspecific distribution into the body, hamper the development of siRNA-based therapeutics. Poly(lactide-co-glycolide), (PLGA) microspheres can be a useful tool to overcome these issues. siRNA can be encapsulated into the PLGA microspheres, which protects the loaded nucleic acid against the enzymatic degradation. Moreover, PLGA microspheres can be injected directly into the action site, where the siRNA can be released in controlled manner, thus avoiding the need of frequent invasive administrations. The complete biodegradability of PLGA to monomers easily metabolized by the body, and its approval by FDA and EMA for parenteral administration, assure the safety of this copolymer and do not require the removal of the device after the complete drug release. In chapter, a basic protocol for the preparation of PLGA microspheres encapsulating siRNA is described. This protocol is based on a double emulsion/solvent evaporation technique, a well known and easy to reproduce method. This specific protocol has been developed to encapsulate a siRNA anti-TNFα in PLGA microspheres, and it has been designed and optimized to achieve high siRNA encapsulation efficiency and slow siRNA release in vitro. However, it can be extended also to other siRNA as well as other RNA or DNA-based oligonucleotides (miRNA, antisense, decoy, etc.). Depending on the applications, chemical modifications of the backbone and site-specific modification within the siRNA sequences could be required.

  16. Yttrium-90 selective internal radiation therapy with glass microspheres for hepatocellular carcinoma: Current and updated literature review

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Wolfgang; Alanic, Lourdes [Div. of Interventional Radiology, Dept. of Radiology, UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles (United States); Cho, Sung Ki [Div. of Interventional Radiology, Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Saab, Sammy [Div. of Hepatology, Dept. of Medicine, Pfleger Liver Institute, University of California at Los Angeles, Los Angeles (United States)

    2016-07-15

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.

  17. Yttrium-90 Selective Internal Radiation Therapy with Glass Microspheres for Hepatocellular Carcinoma: Current and Updated Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Wolfgang; Alanis, Lourdes [Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Cho, Sung-Ki [Division of Interventional Radiology, Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351 (Korea, Republic of); Saab, Sammy [Division of Hepatology, Department of Medicine, Pfleger Liver Institute, University of California at Los Angeles, Los Angeles, CA 90024 (United States)

    2016-11-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.

  18. Synthesis and microwave absorption properties of yolk-shell microspheres with magnetic iron oxide cores and hierarchical copper silicate shells.

    Science.gov (United States)

    Liu, Jiwei; Cheng, Jin; Che, Renchao; Xu, Junjie; Liu, Mengmei; Liu, Zhengwang

    2013-04-10

    Yolk-shell microspheres with magnetic Fe3O4 cores and hierarchical copper silicate shells have been successfully synthesized by combining the versatile sol-gel process and hydrothermal reaction. Various yolk-shell microspheres with different core size and shell thickness can be readily synthesized by varying the experimental conditions. Compared to pure Fe3O4, the as-synthesized yolk-shell microspheres exhibit significantly enhanced microwave absorption properties in terms of both the maximum reflection loss value and the absorption bandwidth. The maximum reflection loss value of these yolk-shell microspheres can reach -23.5 dB at 7 GHz with a thickness of 2 mm, and the absorption bandwidths with reflection loss lower than -10 dB are up to 10.4 GHz. Owing to the large specific surface area, high porosity, and synergistic effect of both the magnetic Fe3O4 cores and hierarchical copper silicate shells, these unique yolk-shell microspheres may have the potential as high-efficient absorbers for microwave absorption applications.

  19. Targeting of liver tumour in rats by selective delivery of holmium-166 loaded microspheres: a biodistribution study

    Energy Technology Data Exchange (ETDEWEB)

    Nijsen, F.; Rook, D.; Zonnenberg, B.; Klerk, J. de; Rijk, P. van; Schip, F. van het [Dept. of Nuclear Medicine, University Medical Center, Utrecht (Netherlands); Brandt, C. [Animal Inst., Utrecht Univ. (Netherlands); Meijer, R. [Dept. of Radiology, Univ. Medical Center, Utrecht (Netherlands); Dullens, H. [Dept. of Pathology, Univ. Medical Center, Utrecht (Netherlands); Hennink, W. [Dept. of Pharmaceutics, Utrecht Univ. (Netherlands)

    2001-06-01

    Intra-arterial administration of beta-emitting particles that become trapped in the vascular bed of a tumour and remain there while delivering high doses, represents a unique approach in the treatment of both primary and metastatic liver tumours. Studies on selective internal radiation therapy of colorectal liver metastases using yttrium-90 glass microspheres have shown encouraging results. This study describes the biodistribution of 40-{mu}m poly lactic acid microspheres loaded with radioactive holmium-166, after intra-arterial administration into the hepatic artery of rats with implanted liver tumours. Radioactivity measurements showed >95% retention of injected activity in the liver and its resident tumour. The average activity detected in other tissues was {<=}0.1%ID/g, with incidental exceptions in the lungs and stomach. Very little {sup 166}Ho activity was detected in kidneys (<0.1%ID/g), thereby indicating the stability of the microspheres in vivo. Tumour targeting was very effective, with a mean tumour to liver ratio of 6.1{+-}2.9 for rats with tumour (n=15) versus 0.7{+-}0.5 for control rats (n=6; P<0.001). These ratios were not significantly affected by the use of adrenaline. Histological analysis showed that five times as many large (>10) and medium-sized (4-9) clusters of microspheres were present within tumour and peritumoural tissue, compared with normal liver. Single microspheres were equally dispersed throughout the tumour, as well as normal liver parenchyma. (orig.)

  20. Fe₃O₄/PVIM-Ni²⁺ magnetic composite microspheres for highly specific separation of histidine-rich proteins.

    Science.gov (United States)

    Zhang, Yuting; Li, Dian; Yu, Meng; Ma, Wanfu; Guo, Jia; Wang, Changchun

    2014-06-11

    Integration of the advantages of immobilized metal-ion affinity chromatography (IMAC) and magnetic microspheres is considered as an ideal pathway for quick and convenient separation of his-tagged proteins, but rare reports concern the natural histidine-rich proteins. In this article, a novel route was presented to fabricate magnetic microspheres composed of a high-magnetic-response magnetic supraparticle (Fe3O4) core and a Ni(2+)-immobilized cross-linked polyvinyl imidazole (PVIM) shell via reflux-precipitation polymerization. The unique as-prepared Fe3O4/PVIM-Ni(2+) microspheres possessed uniform flower-like structure, high magnetic responsiveness, abundant binding sites, and very easy synthesis process. Taking advantage of the pure PVIM-Ni(2+) interface and high Ni(2+) loading amount, the microspheres exhibited remarkable selectivity, excellent sensitivity, large enrichment capacity, and high recyclability in immobilization and separation of his-tagged recombinant proteins. More interestingly, it was found that the Fe3O4/PVIM-Ni(2+) microspheres also showed excellent performance for removal of the natural histidine-rich bovine serum albumin (BSA) from the complex real sample of fetal bovine serum due to the exposed histidine residues. Considering their multiple merits, this new type of Fe3O4/PVIM-Ni(2+) nanomaterial displays great potential in enriching low-abundant his-tagged proteins or removing high-abundant histidine-rich natural proteins for proteomic analysis.

  1. Interfacial Fast Release Layer in Monodisperse Poly (lactic-co-glycolic acid) Microspheres Accelerates the Drug Release.

    Science.gov (United States)

    Wu, Jun; Zhao, Xiaoli; Yeung, Kelvin W K; To, Michael K T

    2016-01-01

    Understanding microstructural evolutions of drug delivery devices during drug release process is essential for revealing the drug release mechanisms and controlling the drug release profiles. In this study, monodisperse poly (lactic-co-glycolic acid) microspheres in different diameters were fabricated by microfluidics in order to find out the relationships between the microstructural evolutions and the drug release profiles. It was found that poly (lactic-co-glycolic acid) microspheres underwent significant size expansion which took place from the periphery to the center, resulting in the formation of interfacial fast release layers. At the same time, inner pores were created and the diffusion rate was increased so that the early stage drug release was accelerated. Due to the different expansion rates, small poly (lactic-co-glycolic acid) microspheres tendered to follow homogeneous drug release while large poly (lactic-co-glycolic acid) microspheres tendered to follow heterogeneous drug release. This study suggests that the size expansion and the occurrence of interfacial fast release layer were important mechanisms for early stage drug release of poly (lactic-co-glycolic acid) microspheres.

  2. Preparation of Functional Fluorescent Microspheres Used for HTS and Their Interaction with Biomolecules

    Institute of Scientific and Technical Information of China (English)

    LIU Bai-ling; LI Song-Jun

    2004-01-01

    There is considerable interest in protein adsorption onto microspheres because of its importance in a wide range of biomedical applications, such as artificial tissues and organs, drug delivery systems, biosensors, solid-phase immunoassays, immunomagnetic cell separation and immobilized enzymes or catalyst. It has been well known that the interaction between proteins and microspheres plays important roles in this process. Major interaction involved in the adsorption can be classified as electrostatic, hydrophobic and hydrogen-bonding. Indeed, adsorption of proteins onto microspheres is a complex process and often can involve many dynamic steps, from the initial attachment of the protein on the surface of microspheres to the equilibrium. Also the conformation of proteins probably occurs to a certain degree of deformation or structural change due to the large area of contact. Recently, much interest has been shown in sulfonated microspheres, since sulfonate-group itself is one of components in bio-bodies, as well as is sensitive to the change of pH or ionic strength. Indeed, so far, scanty investigations have been performed in the full range. Also few researches have involved the data on adsorption rate and the maximum amount of protein adsorbed, or the reversibility of the process and conformational change of protein adsorbed as well.In present study, BSA (bovine serum albumin) was chosen as the model protein and sulfonated PMMA [poly(methyl methacrylate)] microspheres as the matrix to investigate the adsorption process.The purpose is to show some information especially the intrinsic information involved by the adsorption process Adsorption of BSA onto sulfonated microspheres (MS) has been investigated as a function of time, protein concentration and pH. The adsorption appears to be a reversible process and the presence of sulfonate groups can play important roles in the adsorption process, so as to increase the amount of protein adsorbed and influences the

  3. Pluronic F127/chitosan blend microspheres for mucoadhesive drug delivery

    Science.gov (United States)

    Gu, W. Z.; Hu, X. F.

    2017-01-01

    Pluronic F127/chitosan blend microspheres were prepared via emulsification and cross-linking process using glutaraldehyde as a cross-linker. Compared with chitosan microspheres fabricated under the same experimental conditions, blend microspheres exhibited better physical stability and higher swelling capacity. Puerarin, a traditional Chinese medicine, was incorporated into microparticlesas the model drug. The in vitro release of puerarin from blend microspheres was reduced because of the improved compatibility of the drug with the matrices. According to the results from in vitro adhesion experiments, mucoadhesive behavior of blend microspheres on a mucosa-like surface was similar to that of chitosan microspheres, despite their good ability of anti-protein absorption in solution.

  4. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA loading and polymer composition on the mean...... diameter, encapsulation efficiency and FA released from the microspheres were determined. The solid-state and phase separation properties of the microspheres were characterized using DSC, XRPD, Raman spectroscopy, SEM, laser confocal and real time recording of single microspheres formation. Above a loading...... of 1% (w/w) FA phase separated from PLGA polymer and formed distinct spherical FA-rich amorphous microdomains throughout the PLGA microsphere. For FA-loaded PLGA microspheres, encapsulation efficiency and cumulative release increased with initial drug loading. Similarly, cumulative release from FA...

  5. Method of detecting luminescent target ions with modified magnetic microspheres

    Science.gov (United States)

    Shkrob, Ilya A; Kaminski, Michael D

    2014-05-13

    This invention provides methods of using modified magnetic microspheres to extract target ions from a sample in order to detect their presence in a microfluidic environment. In one or more embodiments, the microspheres are modified with molecules on the surface that allow the target ions in the sample to form complexes with specific ligand molecules on the microsphere surface. In one or more embodiments, the microspheres are modified with molecules that sequester the target ions from the sample, but specific ligand molecules in solution subsequently re-extract the target ions from the microspheres into the solution, where the complexes form independent of the microsphere surface. Once the complexes form, they are exposed to an excitation wavelength light source suitable for exciting the target ion to emit a luminescent signal pattern. Detection of the luminescent signal pattern allows for determination of the presence of the target ions in the sample.

  6. Albumin microspheres labeled with Ga-67 by chelation: concise communication.

    Science.gov (United States)

    Hnatowich, D J; Schlegel, P

    1981-07-01

    Albumin microspheres have been synthesized eith EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +/- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +/- 16)% of the activity localizes in the lungs at 5 min, with (60 +/- 7)% remaining after 2 hr. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  7. Laser-assisted fabrication of highly viscous alginate microsphere

    Science.gov (United States)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  8. MULTIMODE THEORY OF WHISPERING GALLERY-MODE MICROSPHERE LASER

    Institute of Scientific and Technical Information of China (English)

    CHAI JIN-HUA; LU YI-QUN; LEUNG PUI-TANG

    2000-01-01

    A multimode theory of whispering-gallery-mode microsphere laser is developed based on the linear and nonlinear semiclassical theory of the microsphere laser. The average photon-number of each lasing mode and the pumping level requirement for multimode coexistence are derived. The comparison between the theory and experimental results shows that the theory can be used to treat the practical problems on microsphere laser.

  9. Phase Transformation Dynamics in Porous Battery Electrodes

    CERN Document Server

    Ferguson, Todd R

    2014-01-01

    Porous electrodes composed of multiphase active materials are widely used in Li-ion batteries, but their dynamics are poorly understood. Two-phase models are largely empirical, and no models exist for three or more phases. Using a modified porous electrode theory based on non-equilibrium thermodynamics, we show that experimental phase behavior can be accurately predicted from free energy models, without artificially placing phase boundaries or fitting the open circuit voltage. First, we simulate lithium intercalation in porous iron phosphate, a popular two-phase cathode, and show that the zero-current voltage gap, sloping voltage plateau and under-estimated exchange currents all result from size-dependent nucleation and mosaic instability. Next, we simulate porous graphite, the standard anode with three stable phases, and reproduce experimentally observed fronts of color-changing phase transformations. These results provide a framework for physics-based design and control for electrochemical systems with comp...

  10. Increasing sensitivity and angle-of-view of mid-wave infrared detectors by integration with dielectric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Kenneth W., E-mail: kenneth.allen@gtri.gatech.edu; Astratov, Vasily N., E-mail: astratov@uncc.edu [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); UES, Dayton, Ohio 45433 (United States); Abolmaali, Farzaneh [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Duran, Joshua M.; Ariyawansa, Gamini; Limberopoulos, Nicholaos I. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Urbas, Augustine M. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, Ohio 45433 (United States)

    2016-06-13

    We observed up to 100 times enhancement of sensitivity of mid-wave infrared photodetectors in the 2–5 μm range by using photonic jets produced by sapphire, polystyrene, and soda-lime glass microspheres with diameters in the 90–300 μm range. By finite-difference time-domain (FDTD) method for modeling, we gain insight into the role of the microspheres refractive index, size, and alignment with respect to the detector mesa. A combination of enhanced sensitivity with angle-of-view (AOV) up to 20° is demonstrated for individual photodetectors. It is proposed that integration with microspheres can be scaled up for large focal plane arrays, which should provide maximal light collection efficiencies with wide AOVs, a combination of properties highly attractive for imaging applications.

  11. Porous membranes in secondary battery technologies.

    Science.gov (United States)

    Lu, Wenjing; Yuan, Zhizhang; Zhao, Yuyue; Zhang, Hongzhang; Zhang, Huamin; Li, Xianfeng

    2017-04-18

    Secondary batteries have received huge attention due to their attractive features in applications of large-scale energy storage and portable electronic devices, as well as electrical vehicles. In a secondary battery, a membrane plays the role of separating the anode and cathode to prevent the occurrence of a short circuit, while allowing the transport of charge carriers to achieve a complete circuit. The properties of a membrane will largely determine the performance of a battery. In this article, we review the research and development progress of porous membranes in secondary battery technologies, such as lithium-based batteries together with flow batteries. The preparation methods as well as the required properties of porous membranes in different secondary battery technologies will be elucidated thoroughly and deeply. Most importantly, this review will mainly focus on the optimization and modification of porous membranes in different secondary battery systems. And various modifications on commercial porous membranes along with novel membrane materials are widely discussed and summarized. This review will help to optimize the membrane material for different secondary batteries, and favor the understanding of the preparation-structure-performance relationship of porous membranes in different secondary batteries. Therefore, this review will provide an extensive, comprehensive and professional reference to design and construct high-performance porous membranes.

  12. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    A novel magnetic poly(vinyl acetate (VAc)–divinyl benzene (DVB)) material (8–34 μm) was synthesized by copolymerization of vinyl acetate and divinyl benzene using oleic acid-stabilized magnetic colloids as magnetic cores. The magnetic colloids and the copolymer microspheres were characterized...... with transmission and scanning electron microscopes, respectively. Magnetization of the microspheres could be described by the Langevin function. All the observations indicated that the microspheres were superparamagnetic. Magnetic sedimentation of the microspheres was achieved within 3 min, over 300 times faster...

  13. Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate Microspheres

    Directory of Open Access Journals (Sweden)

    Ipsita Roy

    2011-07-01

    Full Text Available Poly(3-hydroxybutyrate, P(3HB, produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB microspheres using a solid-in-oil-water (s/o/w technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 µm to 1.54 µm with specific surface areas varying between 9.60 m2/g and 6.05 m2/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB microspheres developed in this research has shown high potential to be used in various biomedical applications.

  14. Poly(styrene-acrylic acid) magnetic polymer microspheres

    Institute of Scientific and Technical Information of China (English)

    Yanling CHENG; Liuqiang MA; Ruohui LI

    2008-01-01

    Magnetic polymer microspheres have been considered as a kind of new biopolymer materials with great advantages in bioseparation engineering and biome-dicine engineering because they have not only polymer functional groups but also magnetic characteristics. Styrene-acrylic acid copolymer (p(S-AA)) magnetic microspheres were synthesized by dispersion polymeriza-tion with Fe3O4 as core and p(S-AA) as shell. The micro-spheres were characterized by SEM, size analysis, molecular weight and solid content measurement. All of them indicate that the microspheres are small in size, nar-row in distribution, stable in chemistry and rich in func-tional groups on their surface.

  15. Preparation and Characterization of Albumin Microspheres Encapsulated with Propranolol HCl

    Directory of Open Access Journals (Sweden)

    Sayyed Abolghassem Sajadi Tabassi

    2003-10-01

    Full Text Available Albumin microspheres (AMS have found many applications in the diagnosis and treatment in recent years and more than 100 diagnostic agents and drugs have been incorporated into AMS. In the present study Bovine Serum Albumin (BSA based microspheres bearing propranolol hydrochloride were prepared by an emulsion-internal phase stabilization technique. The prepared microspheres were studied for particle size distribution, drug loading, release characteristics, bioadhesion and in-vitro controlled diffusion across the rat intestine. The microspheres had mean diameters between 1-25 mm of which more than 50 percent were below 5 mm. The encapsulated drug was found to be about 9% w/w of that initially added to microspheres and the superficial drug was 25% of the total amount of the encapsulated drug. Also AMS were noted to possess good bioadhesion in such a way that about 70% of microspheres remained adherent on the surface mucosa of rat jejunum.The drug release from albumin microspheres was mainly controlled by diffusion and showed a biphasic pattern with a high initial release (burst effect, followed by a more gradual terminal release. The total amount of drug released from microspheres after 12h was 70%. In vitro experiments on the rat intestinal segments revealed that the microspheres could effectively pass their content through intestinal membrane.

  16. Chitosan microspheres in PLG films as devices for cytarabine release.

    Science.gov (United States)

    Blanco, M D; Gómez, C; Olmo, R; Muñiz, E; Teijón, J M

    2000-07-20

    Cytarabine was included in chitosan microspheres and several of these microspheres were embedded in a poly(lactide-co-glycolide) (PLG) film to constitute a comatrix system, to develop a prolonged release form. Chitosan microspheres, in the range of 92+/-65 microm, having good spherical geometry and a smooth surface incorporating cytarabine, were prepared. The cytarabine amount included in chitosan microspheres was 43.7 microg of ara-C per milligram microsphere. The incorporation efficiency of the cytarabine in microspheres was 70.6%. Total cytarabine release from microspheres in vitro was detected at 48 h. Inclusion of cytarabine-loaded microspheres in poly(lactide-co-glycolide) film initiated a slower release of the drug and, in this way, the maximum of cytarabine released (80%) took place in vitro at 94.5 h. Comatrices, with 8.7 mg of cytarabine, signifying a dose of 34.5 microg/kg, were subcutaneously implanted in the back of rats. Maximum plasma cytarabine concentration was 18.5+/-1.5 microg/ml, 48 h after the device implantation and the drug was detected in plasma for 13 days. The histological studies show a slow degradative process. After 6 months of implantation, most of the microspheres of the matrix seemed to be intact, the comatrix appeared surrounded by conjunctive tissue and small blood vessels and nerve packets were detected in the periphery of the implant.

  17. Synthesis of raspberry-like magnetic polystyrene microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhizhong [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Xia Ao [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Wang Changchun [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)]. E-mail: ccwang@fudan.edu.cn; Yang Wuli [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Fu Shoukuang [Key Laboratory of Molecular Engineering of Polymers (Ministry of Education), Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)

    2007-06-15

    Raspberry-like magnetic polystyrene microspheres were prepared via soap-free emulsion polymerization using 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V50) as initiator. The effect of polymerization parameters, such as initiator type, initiator content and the feeding sequence on the particle size and morphology of magnetic polystyrene microspheres, were examined. The final magnetic polystyrene microspheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The experimental results showed that V50 was a suitable initiator for preparation of raspberry-like magnetic polystyrene microspheres.

  18. Photocatalytic Degradation of Rhodamine B Dye over Novel Porous TiO2-SnO2 Nanocomposites Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2014-01-01

    Full Text Available The photocatalytic degradation of Rhodamine B dye was successfully carried out under UV irradiation over porous TiO2-SnO2 nanocomposites with various molar ratios of Ti/Sn (4–12 synthesized by hydrothermal method using polystyrene microspheres as template. The combination of TiO2 with SnO2 can obtain high quantum yield of TiO2, and then achieve the high photocatalytic activity. And its porous structure can provide large surface area, leading to more adsorption and fast transfer of dye pollutant. Structural and textural features of the samples were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, and N2 sorption techniques. Both adsorption and UV irradiation contribute to decolorization of about 100% of Rhodamine B dye over the sample TiSn10 after 30 min of the photocatalytic reaction, while the decomposition of Rhodamine B dye is only 62% over pure titania (Degussa P25.

  19. Development Of Porous Glass Fiber Optic Sensors

    Science.gov (United States)

    Macedo, P. B.; Barkatt, Aa.; Feng, X.; Finger, S. M.; Hojaji, H.; Laberge, N.; Mohr, R.; Penafiel, M.; Saad, E.

    A method for producing rugged, continuous porous glass fiber optic sensors was developed. pH and temperature sensors based on this technology have been successfully produced. The sensor portion of the fiber is made porous by selective leaching of a specially formulated borosilicate glass fiber. This results in a strong, monolithic structure where the sensor portion of the fiber remains integrally attached to the rest of the fiber (which acts as a light pipe), essentially eliminating losses at the sensor-light pipe interface. Pore size in the sensor can be controllably varied by modifying heat treatment conditions, making these sensors suitable for chemical concentration measurements in liquids and gases. Appropriate dyes were chemically bonded by silanization to the large interior surface area of the porous sensors to produce the pH and temperature sensors. Cresol red and phenol red were used for pH and pinacyanol chloride was used for temperature sensing. The sensitivity of these devices can be controlled by varying the concentration of the chemically bonded dye and the length of the porous region. Optical absorbance measurements were made in the visible range. The tip of the sensors was coated with a thin, porous layer of gold to reflect the incident light, resulting in a double pass across the porous sensor. Experimental measurements were made over a pH range of 3 to 8 and a temperature range of 28-70 C. These porous glass fiber optic sensors were found to be rugged and reliable due to their monolithic structure and large interior surface area for attachment of active species. A broad range of sensors based on this technology could be developed by using different active species, such as enzymes and other biochemicals, which could be bonded to the interior surface of the porous glass sensor.

  20. Erythrocyte-Like Mg(OH)2 Microspheres Self-Assembled by Nanocrystallites

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The erythrocyte-like magnesium hydroxide microspheres were synthesized in large scale through a simple solution phase route. The structures and morphologies of the products were analyzed by the X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM). The possible growth mechanism of the nanostructure was discussed briefly and the potential application was proposed.

  1. Water-compatible magnetic imprinted microspheres for rapid separation and determination of triazine herbicides in environmental water.

    Science.gov (United States)

    Qiao, Fengxia; Row, Kyung Ho; Wang, Mengge

    2014-04-15

    A novel kind of water-compatible magnetic imprinted cyromazine microsphere (WCMM) was synthesized by water/oil/water suspension polymerization. The obtained WCMM was homogenously spherical with porous morphology and strong magnetic properties. The microspheres were successfully used as adsorbent in dispersive solid-phase extraction (WCMM-dSPE) to selectively extract cyanazine and atrazine from environmental water. Good linearity of the two analytes was observed in the range from 2.5 to 200.0ngmL(-1). The average recoveries at three spiking levels ranged from 84.8% to 104.3% with relative standard deviations (RSD) less than 6.9%. Compared with magnetic non-imprinted particles (WCMN), the proposed WCMM adsorbent of dSPE efficiently improved the efficiency of extracting cyanazine and atrazine from environmental water samples and eliminated the effect of cyromazine leakage on the quantitative analysis of cyanazine and atrazine. The proposed WCMM-dSPE method combined the advantages of magnetic separation, molecular imprinted microspheres and dSPE. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Growth Kinetics of Monodisperse Polystyrene Microspheres Prepared by Dispersion Polymerization

    Directory of Open Access Journals (Sweden)

    Fan Li

    2013-01-01

    Full Text Available Dispersion polymerization has been widely applied to the synthesis of monodisperse micron-sized polymer colloidal spheres. Many efforts have been devoted to studying the influence of initial conditions on the size and uniformity of the resultant microspheres, aiming to synthesize micron-size monodisperse colloidal spheres. However, the inner contradiction between the size and the size distribution of colloidal spheres hinders the realization of this goal. In this work, we drew our attention from the initial conditions to the growth stage of dispersion polymerization. We tracked the size evolution of colloidal sphere during the dispersion polymerization, through which we established a kinetic model that described the relationship between the monomer concentration and the reaction time. The model may provide a guideline to prepare large polymer colloidal spheres with good monodispersity by continuous monomer feeding during the growth stage to maintain the concentration of monomer at a constant value in a dispersion polymerization process.

  3. Neutron transmission measurements on hydrogen filled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Dyrnjaja, Eva, E-mail: dyrnjaja@ati.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria); Hummel, Stefan, E-mail: hummel@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Keding, Marcus, E-mail: keding@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Smolle, Marie-Theres, E-mail: marie-theres.smolle@tuwien.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria); Gerger, Joachim, E-mail: gerger@fotec.at [FOTEC GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt (Austria); Zawisky, Michael, E-mail: zawisky@ati.ac.at [Vienna University of Technology, Institute of Atomic and Subatomic Physics, Stadionallee 2, Vienna (Austria)

    2014-01-01

    Hollow microspheres are promising candidates for future hydrogen storage technologies. Although the physical process for hydrogen diffusion through glass is well understood, measurements of static quantities (e.q. hydrogen pressure inside the spheres) as well as dynamic properties (e.g. diffusion rate of hydrogen through glass) are still difficult to handle due to the small size of the spheres (d≈15μm). For diffusion rate measurements, the long-term stability of the experiment is also mandatory due to the relatively slow diffusion rate. In this work, we present an accurate and long-term stable measurement technique for static and dynamic properties, using neutron radiography. Furthermore, possible applications for hydrogen filled microspheres within the scope of radiation issues are discussed.

  4. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  5. Aptamer Based Microsphere Biosensor for Thrombin Detection

    Directory of Open Access Journals (Sweden)

    Xudong Fan

    2006-08-01

    Full Text Available We have developed an optical microsphere resonator biosensor using aptamer asreceptor for the measurement of the important biomolecule thrombin. The sphere surface ismodified with anti-thrombin aptamer, which has excellent binding affinity and selectivityfor thrombin. Binding of the thrombin at the sphere surface is monitored by the spectralposition of the microsphere’s whispering gallery mode resonances. A detection limit on theorder of 1 NIH Unit/mL is demonstrated. Control experiments with non-aptameroligonucleotide and BSA are also carried out to confirm the specific binding betweenaptamer and thrombin. We expect that this demonstration will lead to the development ofhighly sensitive biomarker sensors based on aptamer with lower cost and higher throughputthan current technology.

  6. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  7. Solvent-free fabrication of polyHIPE microspheres for controlled release of growth factors.

    Science.gov (United States)

    Moglia, Robert; Whitely, Michael; Brooks, Megan; Robinson, Jennifer; Pishko, Michael; Cosgriff-Hernandez, Elizabeth

    2014-07-01

    The growth factor bone morphogenetic protein 2 (BMP-2) is utilized in surgical procedures to improve bone regeneration; however, current treatments deliver BMP-2 at amounts greater than 100,000 fold of physiological levels, which increases treatment costs and risk of side effects. Drug-eluting microcarriers developed to improve these therapies have faced significant commercialization challenges including particle size distributions, solvent removal, low encapsulation efficiency, and bioactivity loss. In this study, a solvent-free method is presented for fabrication of uniform polyHIPE microspheres for controlled growth factor release. Emulsion templating principles and fluid dynamics were used to fabricate uniform particles with tunable particle size (200-800 μm) and pore size (10-30 μm). The ability to independently tune particle and pore size is expected to provide excellent control of release kinetics. Overall, this solvent-free method for making porous microspheres displays strong promise for the controlled release of BMP-2 and other growth factors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Hierarchical Porous Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grote, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-07

    Materials Design is often at the forefront of technological innovation. While there has always been a push to generate increasingly low density materials, such as aero or hydrogels, more recently the idea of bicontinuous structures has gone more into play. This review will cover some of the methods and applications for generating both porous, and hierarchically porous structures.

  9. A POROUS, LAYERED HELIOPAUSE

    Energy Technology Data Exchange (ETDEWEB)

    Swisdak, M.; Drake, J. F. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Opher, M., E-mail: swisdak@umd.edu, E-mail: drake@umd.edu, E-mail: mopher@bu.edu [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)

    2013-09-01

    The picture of the heliopause (HP)-the boundary between the domains of the Sun and the local interstellar medium (LISM)-as a pristine interface with a large rotation in the magnetic field fails to describe recent Voyager 1 (V1) data. Magnetohydrodynamic (MHD) simulations of the global heliosphere reveal that the rotation angle of the magnetic field across the HP at V1 is small. Particle-in-cell simulations, based on cuts through the MHD model at V1's location, suggest that the sectored region of the heliosheath (HS) produces large-scale magnetic islands that reconnect with the interstellar magnetic field while mixing LISM and HS plasma. Cuts across the simulation reveal multiple, anti-correlated jumps in the number densities of LISM and HS particles, similar to those observed, at the magnetic separatrices. A model is presented, based on both the observations and simulations, of the HP as a porous, multi-layered structure threaded by magnetic fields. This model further suggests that contrary to the conclusions of recent papers, V1 has already crossed the HP.

  10. Effects of crosslinking temperature and time on microstructure and stability of cassava starch microspheres.

    Science.gov (United States)

    Puncha-Arnon, Santhanee; Jiranuntakul, Wittawat; Uttapap, Dudsadee

    2015-12-10

    Starch microspheres (SMs) were prepared by a water-in-water emulsion-crosslinking technique at 4 °C and 30 °C for 1, 6, 12 and 24h; the SMs obtained were analyzed for crosslinking density, morphology, crystalline structure, and stability against temperature, pH, and α-amylase hydrolysis. The crosslinking degree at 30 °C was considerably higher than that at 4 °C. SMs prepared at 4 °C for less than 12h incubation had larger size and more porous structure as compared with those prepared at 30 °C, but the morphology became comparable (spherical shape with smooth surface and dense structure) after 24h incubation. All SMs samples displayed amorphous structure. Stability tests revealed that the SMs were very stable under acidic and mild basic pH; however, stability against α-amylase hydrolysis varied depending on incubation temperature and time.

  11. Unstirred Water Layer Effects on Biodegradable Microspheres

    Directory of Open Access Journals (Sweden)

    Susan D’Souza

    2015-01-01

    Full Text Available This study explores the mechanistic aspects of in vitro release from biodegradable microspheres with the objective of understanding the effect of the unstirred water layer on polymer degradation and drug release. In vitro drug release experiments on Leuprolide PLGA microspheres were performed under “static” and “continuous” agitation conditions using the “sample and separate” method. At specified time intervals, polymer degradation, mass loss, and drug release were assessed. While molecular weight and molecular number profiles for “static” and “continuous” samples were indistinct, mass loss occurred at a faster rate in “continuous” samples than under “static” conditions. In vitro results describe a fourfold difference in drug release rates between the “continuous” and “static” samples, ascribed to the acceleration of various processes governing release, including elimination of the boundary layer. The findings were confirmed by the fourfold increase in drug release rate when “static” samples were subjected to “continuous” agitation after 11 days. A schema was proposed to describe the complex in vitro release process from biodegradable polymer-drug dosage forms. These experiments highlight the manner in which the unstirred water layer influences drug release from biodegradable microspheres and stress the importance of selecting appropriate conditions for agitation during an in vitro release study.

  12. STUDIES AND EVALUATION OF COMPRESSED MICROSPHERES

    Directory of Open Access Journals (Sweden)

    Idris Mohamed El-Mahdi

    2016-05-01

    Full Text Available This work was aimed at the use of dissolution testing and similarity factor to assess the level of damage taken by active drug microspheres during compression in tablet dosage form. To achieve that, combinations of suitable excipients were used to protect drug microspheres during compression. The excipients were used in the form of powders, granules or placebo pellets prepared by extrusion-spheronization technology. The excipients were evaluated alone, in combinations and post-compression into compacts.  Preliminary experiments included density, hardness, friability and disintegration on all of the selected excipients. Based on such experiments it was found that the flowability of combination powders was more acceptable than individual excipients. Two combinations of microcrystalline -starch and microcrystalline cellulose -calcium carbonate granules were selected to be compressed with active ketoprofen pellets. In all the combinations used there was a significant amount of damage to drug pellets.  The kinetics of drug release appears to follow the zero-order rate and the rate remained unchanged even when a significant degree of damage to pellets occur. It was found that a high level of excipients is required in order to prepare microspheres as a rapid disintegrating tablet. Citation DOI: 10.21502/limuj.002.01.2016  LIMUJ is licensed under a Creative Commons Attribution 4.0 International License

  13. Custom-Made Microspheres for Optical Tweezers.

    Science.gov (United States)

    Jannasch, Anita; Abdosamadi, Mohammad K; Ramaiya, Avin; De, Suman; Ferro, Valentina; Sonnberger, Aaron; Schäffer, Erik

    2017-01-01

    Due to their high position and force sensitivity and the ability to remotely apply forces and torques, optical tweezers are widely used in diverse fields, such as biology, material science, and physics. Often, small dielectric particles are trapped and used as probes, which for experimental convenience are mostly spherical and composed of silica or polystyrene. The optical properties of these materials together with the microsphere size determine the trapping efficiency, and the position and force resolution. However, using only a single, homogeneous, isotropic, and unstructured material limits the range of trapping properties and thereby the applications of optical tweezers. Here, we show how custom-made microspheres composed of coated high-refractive-index materials-titania and nanodiamonds-and birefringent, liquid crystals extend the range and combination of desired trapping properties. These custom-made microspheres either enable the generation of high forces, a high force or time resolution, or the applications of torques. Custom-made probes expand the range of possible experiments and approaches broadening the scope and applicability of optical tweezers.

  14. Popcorn balls-like ZnFe2O4-ZrO2 microsphere for photocatalytic degradation of 2,4-dinitrophenol

    Science.gov (United States)

    Chen, Xi; Liu, Yutang; Xia, Xinnian; Wang, Longlu

    2017-06-01

    In this paper, novel popcorn balls-like ZnFe2O4-ZrO2 composite microspheres were successfully fabricated by a simple hydrothermal method. The morphology, structure and optical property of the microspheres were characterized. The microspheres were used as the photocatalysts to degrade 2,4-dinitrophenol, and exhibited superior photocatalytic performance. Under simulated solar visible light irradiation, the degradation rate of ZnFe2O4-ZrO2 photocatalyst (mass ratio of ZnFe2O4/ZrO2 = 2:1) was almost 7.4 and 2.4 times higher than those of pure ZnFe2O4 and ZrO2. The enhancement could attribute to stronger light absorption, lower carrier recombination and multi-porous structure of the microspheres. Moreover, the popcorn balls-like photocatalysts can be easily separated, because of the magnetism of the samples. After five times runs, the photocatalyst still showed 90% of its photocatalytic degradation efficiency. This work demonstrated a good prospect for removing organic pollutants in water.

  15. UV-assisted synthesis of surface modified mesoporous TiO2/G microspheres and its electrochemical performances in lithium ion batteries

    Science.gov (United States)

    Tong, Xiaoling; Zeng, Min; Li, Jing; Li, Fuyun

    2017-01-01

    Three-dimensional mesoporous TiO2/graphene (TiO2/G) microspheres have been successfully synthesized through a simple UV-assisted method of reduced graphene oxide with hydrazine. The as-made surface modified mesoporous TiO2/G microspheres possess large surface area and exhibit a high initial discharge capacity of 220 mAh g-1 and retain 84% (∼185 mAh g-1) of reversible capacity over 100 cycles at a rate of 0.2C. In addition, TiO2/G microspheres display improved cyclic performance, excellent rate capability and enhanced electrical conductivity, which are superior to the bare TiO2 microspheres. Furthermore, TiO2/G microspheres can achieve a reversible capacity of 141 mAh g-1 upon 100 cycles even at the 1C rate. We believe that the mesoporous TiO2/G microspheres are expected to be a promising high performance anode material for the next generation lithium ion batteries.

  16. Optimization of sustained release aceclofenac microspheres using response surface methodology.

    Science.gov (United States)

    Deshmukh, Rameshwar K; Naik, Jitendra B

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14±0.015% to 85.34±0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12h. The optimized microspheres formulation showed E.E. of 84.87±0.005 with small error value (1.39). The low magnitudes of error and the significant value of R(2) in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects.

  17. Hydrothermal Treatment of Tannin: A Route to Porous Metal Oxides and Metal/Carbon Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Flavia L. Braghiroli

    2017-01-01

    Full Text Available In the present paper, porous materials were prepared from the hydrothermal treatment of aqueous solutions of tannin, a renewable phenolic resource extracted from tree barks, containing dissolved salts of transition metals: V, Cr, Ni and Fe. Hydrothermal treatment produced carbonaceous particles doped with the aforementioned metals, and such materials were treated according to two different routes: (i calcination in air in order to burn the carbon and to recover porous oxides; (ii pyrolysis in inert atmosphere so as to recover porous metal/carbon hybrid materials. The nature of the metal salt was found to have a dramatic impact on the structure of the materials recovered by the first route, leading either to nano-powders (V, Cr or to hollow microspheres (Ni, Fe. The second route was only investigated with iron, leading to magnetic Fe-loaded micro/mesoporous carbons whose texture, pore volumes and surface areas gradually changed with the iron content.

  18. SPUTTERING FROM A POROUS MATERIAL BY PENETRATING IONS

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Nieva, J. F. [Instituto Balseiro, Universidad Nacional de Cuyo, 8400 Bariloche (Argentina); Bringa, E. M. [CONICET and Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, 5500 Mendoza (Argentina); Cassidy, T. A. [CalTech/JPL, Pasadena, CA 91109 (United States); Johnson, R. E.; Fama, M.; Baragiola, R. A. [Laboratory for Atomic and Surface Physics, University of Virginia, Charlottesville, VA 22903 (United States); Caro, A. [Los Alamos National Laboratory, Los Alamos, NM 94551 (United States); Loeffler, M. J. [NASA Goddard Space Flight Center, Astrochemistry Branch, Code 691, Greenbelt, MD 20771 (United States); Farkas, D. [Department of Materials Sciences, Virginia Tech, Blacksburg, VA 24061 (United States)

    2011-12-10

    Porous materials are ubiquitous in the universe and weathering of porous surfaces plays an important role in the evolution of planetary and interstellar materials. Sputtering of porous solids in particular can influence atmosphere formation, surface reflectivity, and the production of the ambient gas around materials in space. Several previous studies and models have shown a large reduction in the sputtering of a porous solid compared to the sputtering of the non-porous solid. Using molecular dynamics simulations we study the sputtering of a nanoporous solid with 55% of the solid density. We calculate the electronic sputtering induced by a fast, penetrating ion, using a thermal spike representation of the deposited energy. We find that sputtering for this porous solid is, surprisingly, the same as that for a full-density solid, even though the sticking coefficient is high.

  19. Sputtering from a Porous Material by Penetrating Ions

    Science.gov (United States)

    Rodriguez-Nieva, J. F.; Bringa, E. M.; Cassidy, T. A.; Johnson, R. E.; Caro, A.; Fama, M.; Loeffler, M. J.; Baragiola, R. A.; Farkas, D.

    2011-12-01

    Porous materials are ubiquitous in the universe and weathering of porous surfaces plays an important role in the evolution of planetary and interstellar materials. Sputtering of porous solids in particular can influence atmosphere formation, surface reflectivity, and the production of the ambient gas around materials in space. Several previous studies and models have shown a large reduction in the sputtering of a porous solid compared to the sputtering of the non-porous solid. Using molecular dynamics simulations we study the sputtering of a nanoporous solid with 55% of the solid density. We calculate the electronic sputtering induced by a fast, penetrating ion, using a thermal spike representation of the deposited energy. We find that sputtering for this porous solid is, surprisingly, the same as that for a full-density solid, even though the sticking coefficient is high.

  20. Inorganic porous hollow fiber membranes : with tunable small radial dimensions

    NARCIS (Netherlands)

    Luiten-Olieman, M.W.J.

    2012-01-01

    The objectives of this thesis are twofold. The first aim is to develop of robust coating procedures for thin supported films onto porous ceramic supports. The second aim is the development of a preparation methodology for high quality porous inorganic membranes, with large membrane surface area. A r

  1. Flow in Porous Media with Special Reference to Breakwater Structures

    DEFF Research Database (Denmark)

    Andersen, O. Holst

    A literature study concerning porous flow is carried out. For the stationary case, the hydraulic radius theory, for which some justification can be given based on Navier-Stokes equations, appears to be adequate. Three different porous flow regimes are identified and the associated flow resistance...... of large scale physical experiments carried out in collaboration with other researchers....

  2. High-Capacity and Self-Stabilized Manganese Carbonate Microspheres as Anode Material for Lithium-Ion Batteries.

    Science.gov (United States)

    Xiao, Liang; Wang, Shiyao; Wang, Yafei; Meng, Wen; Deng, Bohua; Qu, Deyu; Xie, Zhizhong; Liu, Jinping

    2016-09-28

    Manganese carbonate (MnCO3) is an attractive anode material with high capacity based on conversion reaction for lithium-ion batteries (LIBs), but its application is mainly hindered by poor cycling performance. Building nanostructures/porous structures and nanocomposites has been demonstrated as an effective strategy to buffer the volume changes and maintain the electrode integrity for long-term cycling. It is widely believed that microsized MnCO3 is not suitable for use as anode material for LIBs because of its poor conductivity and the absence of nanostructure. Herein, different from previous reports, spherical MnCO3 with the mean diameters of 6.9 μm (MnCO3-B), 4.0 μm (MnCO3-M), and 2.6 μm (MnCO3-S) were prepared via controllable precipitation and utilized as anode materials for LIBs. It is interesting that the as-prepared MnCO3 microspheres demonstrate both high capacity and excellent cycling performance comparable to their reported nanosized counterparts. MnCO3-B, MnCO3-M, and MnCO3-S deliver reversible specific capacities of 487.3, 573.9, and 656.8 mA h g(-1) after 100 cycles, respectively. All the MnCO3 microspheres show capacity retention more than 90% after the initial stage. The advantages of MnCO3 microspheres were investigated via constant-current charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that there should be substantial structure transformation from microsized particle to self-stabilized nanostructured matrix for MnCO3 at the initial charge/discharge stage. The evolution of EIS during charge/discharge clearly indicates the formation and stabilization of the nanostructured matrix. The self-stabilized porous matrix maintains the electrode structure to deliver excellent cycling performance, and contributes extra capacity beyond conversion reaction.

  3. Microspheres with Ultrahigh Holmium Content for Radioablation of Malignancies

    NARCIS (Netherlands)

    Bult, W.; Seevinck, P.R.; Krijger, G.C.; Visser, T.; Kroon-Batenburg, L.M.J.; Bakker, C.J.G.; Hennink, W.E.; Van het Schip, A.D.; Nijsen, J.F.W.

    Purpose The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  4. Microspheres with ultrahigh holmium content for radioablation of malignancies

    NARCIS (Netherlands)

    Bult, W; Seevinck, P R; Krijger, G C; Visser, T; Kroon-Batenburg, L M J; Bakker, C J G; Hennink, W E; van het Schip, A D; Nijsen, J F W

    2009-01-01

    PURPOSE: The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  5. Preparation and characterization of albumin-heparin microspheres

    NARCIS (Netherlands)

    Cremers, H.F.M.; Kwon, G.; Bae, Y.H.; Kim, S.W.; Verrijk, R.; Noteborn, H.P.J.M.; Feijen, J.

    1994-01-01

    Albumin-heparin microspheres were prepared by a two-step process which involved the preparation of a soluble albumin-heparin conjugate, followed by formation of microspheres from this conjugate or by a double cross-linking technique involving both coupling of soluble albumin and heparin and microsph

  6. Pectin/zein microspheres as a sustained drug delivery system

    Science.gov (United States)

    A series of microspheres were prepared from pectins and corn proteins from various sources in the presence of the divalent ions calcium or zinc. The results showed that the yield of microsphere and the efficiency of drug incorporation were dependent on the type and ratio of biopolymers, the size of ...

  7. PREPARATION AND ADSORBABILITY OF DEXTRAN MICROSPHERES WITH UNIFORM DIAMETER

    Institute of Scientific and Technical Information of China (English)

    Ri-sheng Yao; Wen-xia Gao; Jing Sun; Ya-hua You

    2005-01-01

    The method of preparing uniform dextran microspheres with a narrow diameter distribution was introduced and the adsorbability of these microspheres was evaluated. The microspheres were prepared in W/O microemulsion using 0.5% dextran solution as the aqueous phase and n-hexane as the oil phase. Characteristics of the prepared dextran microspheres were examined with laser light blocking technique, optical microscope and ultraviolet spectrometer. The results show that the prepared dextran microspheres have uniform morphology and narrow diameter distribution, nearly 92% of them having a diameter of 56.6 μm. In vitro evaluation of adsorbability, wet dextran microspheres have good adsorption of 98.32 mg/g of model drug methylene blue in 20.86 mg/L methylene blue solution at 25℃. The adsorption of dried dextran microspheres under the same condition is 132.15 mg/g, which is even higher. And the adsorbability of dextran microspheres has significant relationship with the concentration of methylene blue and temperature. The adsorbability is better at lower temperature and higher concentration of methylene blue.

  8. Design and Fabrication of Superparamaganitic Hybrid Microspheres for Protein Immobilization

    Institute of Scientific and Technical Information of China (English)

    REN Qi; CHU Hong; CHEN Mingqing; NI Zhongbin; CHEN Qiuyun

    2011-01-01

    Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PStco-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 25.07emu/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-coPAMPS microspheres was 59.62 mg/g microspheres in 120 min.

  9. Antibacterial activity of ciprofloxacin-loaded zein microsphere films

    Energy Technology Data Exchange (ETDEWEB)

    Fu Jianxi [Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (China); Henan Normal University, 46 East Construction Road, Xinxiang, Henan 453007 (China); Wang Huajie [College of Life Science and Biotechnology, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China); Zhou Yanqing [Henan Normal University, 46 East Construction Road, Xinxiang, Henan 453007 (China); Wang Jinye, E-mail: jywang@mail.sioc.ac.cn [Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (China); College of Life Science and Biotechnology, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)

    2009-05-05

    Our aim was to produce an antibiotic-emitting coating composed of zein microspheres for the prevention of bacterial infection on implanted devices. Ciprofloxacin-loaded zein microspheres were prepared using a phase separation procedure, with particle sizes between 0.5 and 2 {mu}m. Drug encapsulation and drug loading varied with the amount of both zein and ciprofloxacin, and the highest encapsulation efficiency was 8.27% (2 mg/ml ciprofloxacin and 20 mg/ml zein; n = 3). A ciprofloxacin-loaded zein microsphere film (CF-MS film) was generated via solvent evaporation. Continuous drug release from a trypsin-degraded microsphere film was observed for up to 28 days. The liberation of ciprofloxacin from the trypsin-degraded film and the biodegradation of the microsphere film were highly correlated. Proliferation assay of the growth of human umbilical vein endothelial cells (HUVECs) by the MTT method showed that the microsphere film had no toxicity when compared with cells grown on Corning culture plates alone and plates with a zein film alone. Quantification of bacteria adhesion showed that adhesion on the microsphere film is significantly suppressed. In addition, according to the results of bacterial growth tests, ciprofloxacin-loaded microsphere films maintained antibacterial activity for more than 6 days. In contrast, a control medium containing a zein film allowed constant bacterial growth. These results indicate that CF-MS films might be useful as antibacterial films on implanted devices.

  10. Coacervate droplets, proteinoid microspheres, and the genetic apparatus

    Science.gov (United States)

    Fox, S. W.

    1974-01-01

    Differences between typical coacervate droplets and typical proteinoid microspheres are examined. It is pointed out that coacervate droplets are produced from polymers obtained from contemporary organisms. The microspheres considered are aggregates of proteinoid formed from monomeric amino acids under geologically relevant conditions. Aspects regarding the primordial sequence are discussed along with the origin of the genetic apparatus and the genetic code.

  11. DEVELOPMENT AND OPTIMIZATION OF FLOATING MICROSPHERES OF GLICLAZIDE

    Directory of Open Access Journals (Sweden)

    Shardendu Prakash

    2015-05-01

    Full Text Available The objective of the present study was to develop floating microspheres of Gliclazide in order to achieve an extended retention in the upper gastrointestinal tract, which may result in enhanced absorption and thereby improved bioavailability. The present study involves preparation and evaluation of floating microspheres using Gliclazide as a model drug for prolongation of the gastric retention time. As gliclazide is mainly absorbed from stomach, thus using floating microspheres as a mode of drug delivery helps in increasing its residence time and hence increasing the bioavailability of drug. The microspheres were prepared by the Ionic gelation method. The average diameter and surface morphology of the prepared microspheres were characterized by optical microscope and scanning electron microscopic methods respectively. The prepared microspheres were evaluated for particle size, micromeritic study, drug entrapment efficiency, in vitro buoyancy, swelling index and in vitro release. The effect of various formulation variables on the size and drug release was also investigated. All the formulated microspheres were found to possess good flow properties. Scanning electron microscopy confirmed spherical structure of the prepared microspheres. The best formulation F3 drug release kinetics were evaluated using Zero order, First order, Higuchi model, Korsmeyer - Peppas model. After the interpretation of data that was based on the value of a resulting regression coefficient, it was observed that the Korsmeyer- Peppas model has a highest regression coefficient values indicating that the drug release was based on the erosion of polymeric chain matrix.

  12. Controlling silk fibroin microspheres via molecular weight distribution

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Research Center of Cooperative Innovation for Functional Organic/Polymer Material Micro/Nanofabrication, Soochow University, Suzhou, Jiangsu 215123 (China)

    2015-05-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K{sub 2}HPO{sub 4}–KH{sub 2}PO{sub 4}). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications.

  13. Formulation, optimization and evaluation of sustained release microsphere of ketoprofen

    Directory of Open Access Journals (Sweden)

    V Chirag Prajapati

    2012-01-01

    Full Text Available The objective of this study is to formulate ketoprofen loaded microspheres of Acrycoat S100 by an o/w emulsion solvent evaporation method. It potently inhibits the enzyme cyclooxygenase resulting in prostaglandin synthesis inhibition. Ketoprofen causes an irritation in the gastrointestinal mucous membrane and possesses a bitter taste and aftertaste. The half-life in plasma is about 1-2hrs. This makes ketoprofen a very good candidate for the formulation of controlled release dosage forms. Ketoprofen microspheres help to protect the gastric mucous membrane from drug irritation and to mask its taste. The prepared microspheres were evaluated for micromeritic properties, particle size, effect of surfactant concentration, percentage yield, incorporation efficiency, drug polymer compatibility (IR and DSC study, scanning electron microscopy and in vitro drug release. The microspheres produced exhibited good encapsulation efficiencies and micromeritic properties. Encapsulation efficiency of microsphere is around 78%. The mean diameters of microspheres were found in required micrometer range. The results of optimized formulations showed a narrow size distribution and smooth surface. The DSC and the FTIR analysis showed the absence of any potent incompatibility between the drug and the polymer. In-vitro release showed 86.4% drug release after 12 hours. Results of present study suggest that Acrycoat S100 loaded microsphere of ketoprofen can be successfully designed to develop sustained drug delivery system. The solvent evaporation method is a suitable technique for the preparation of Acrycoat S100 microspheres for controlling the release of Ketoprofen for a prolonged duration.

  14. Porous squeeze-film flow

    KAUST Repository

    Knox, D. J.

    2013-11-14

    © 2013 © The authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved. The squeeze-film flow of a thin layer of Newtonian fluid filling the gap between a flat impermeable surface moving under a prescribed constant load and a flat thin porous bed coating a stationary flat impermeable surface is considered. Unlike in the classical case of an impermeable bed, in which an infinite time is required for the two surfaces to touch, for a porous bed contact occurs in a finite contact time. Using a lubrication approximation, an implicit expression for the fluid layer thickness and an explicit expression for the contact time are obtained and analysed. In addition, the fluid particle paths are calculated, and the penetration depths of fluid particles into the porous bed are determined. In particular, the behaviour in the asymptotic limit of small permeability, in which the contact time is large but finite, is investigated. Finally, the results are interpreted in the context of lubrication in the human knee joint, and some conclusions are drawn about the contact time of the cartilage-coated femoral condyles and tibial plateau and the penetration of nutrients into the cartilage.

  15. Predicting the pressure-volume curve of an elastic microsphere composite

    CERN Document Server

    De Pascalis, Riccardo; Parnell, William J

    2012-01-01

    The effective macroscopic response of nonlinear elastomeric inhomogeneous materials is of great interest in many applications including nonlinear composite materials and soft biological tissues. The interest of the present work is associated with a microsphere composite material, which is modelled as a matrix-inclusion composite. The matrix phase is a homogeneous isotropic nonlinear rubber-like material and the inclusion phase is more complex, consisting of a distribution of sizes of stiff thin spherical shells filled with gas. Experimentally, such materials have been shown to undergo complex deformation under cyclic loading. Here, we consider microspheres embedded in an unbounded host material and assume that a hydrostatic pressure is applied in the "far-field". Taking into account a variety of effects including buckling of the spherical shells, large deformation of the host phase and evolving microstructure, we derive a model predicting the pressure-relative volume change load curves. Nonlinear constitutive...

  16. Synthesize TiO2 microspheres self-assembled from nanorods via hydrothermal treatment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The TiO2 microspheres were deposited on the glass substrates under certain conditions via hydro-thermal reaction using 0.15 mol·L?1 TiCl3 saturated NaCl aqueous solution adding urea as an additive. The TiO2 is characterized rutile by results of SEM,TEM and XRD techniques,the TiO2 microspheres are large scale assembled from TiO2 nanorods. The affections on the products by the factors of the con-tents of urea being an additive(the key techniques) ,the reaction temperature,the reaction time and the concentration of TiCl3 were studied. The optimum condition was found,and the mechanism of reac-tions was discussed also.

  17. Electrospray formation of gelled nano-aluminum microspheres with superior reactivity.

    Science.gov (United States)

    Wang, Haiyang; Jian, Guoqiang; Yan, Shi; DeLisio, Jeffery B; Huang, Chuan; Zachariah, Michael R

    2013-08-14

    Nanometallic fuels with high combustion enthalpy, such as aluminum, have been proposed as a potential fuel replacement for conventional metallic fuel to improve propellant performance in a variety of propulsive systems. Nevertheless, nanometallic fuels suffer from the processing challenges in polymer formulations such as increased viscosity and large agglomeration, which hinder their implementation. In this letter, we employ electrospray as a means to create a gel within a droplet, via a rapid, solvent evaporation-induced aggregation of aluminum nanoparticles, containing a small mass fraction of an energetic binder. The gelled aluminum microspheres were characterized and tested for their burning behavior by rapid wire heating ignition experiments. The gelled aluminum microspheres show enhanced combustion behavior compared to nanoaluminum, which possibly benefits from the nitrocellulose coating and the gelled microstructure, and is far superior to the corresponding dense micrometer-sized aluminum.

  18. Optimization of sustained release aceclofenac microspheres using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R{sup 2} in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres

  19. Computational dynamics of acoustically-driven microsphere systems

    CERN Document Server

    Glosser, Connor A; Dault, Daniel L; Piermarocchi, Carlo; Shanker, Balasubramaniam

    2015-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the inter-particle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of non-dissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities, and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation ...

  20. Resolution enhancement phase-contrast imaging by microsphere digital holography

    Science.gov (United States)

    Wang, Yunxin; Guo, Sha; Wang, Dayong; Lin, Qiaowen; Rong, Lu; Zhao, Jie

    2016-05-01

    Microsphere has shown the superiority of super-resolution imaging in the traditional 2D intensity microscope. Here a microsphere digital holography approach is presented to realize the resolution enhancement phase-contrast imaging. The system is designed by combining the microsphere with the image-plane digital holography. A microsphere very close to the object can increase the resolution by transforming the object wave from the higher frequency to the lower one. The resolution enhancement amplitude and phase images can be retrieved from a single hologram. The experiments are carried on the 1D and 2D gratings, and the results demonstrate that the observed resolution has been improved, meanwhile, the phase-contrast image is obtained. The proposed method can improve the transverse resolution in all directions based on a single exposure. Furthermore, this system has extended the application of the microsphere from the conventional 2D microscopic imaging to 3D phase-contrast microscopic imaging.

  1. Study on the Degradation of Polylactide Microsphere In Vitro

    Institute of Scientific and Technical Information of China (English)

    HeYing; WeiShuli

    2001-01-01

    This report concentrated on the rules and mechanism of the degradation of polylactide and the microspheres. The rate of degradation was assessed with five methods: observation of microsphere surface morphology by SEM, determination of the weight loss of the microspheres, determination of the molecular mass of the polymers by GPC, determination of pH and determination of the contents of lactic acid by UV spectrophotometry. The degradation of polylactide microspheres showed two-phase characteristics. At the early stage of the degradation, the high molecular mass polymers were cleaved into lower molecular mass fractions and at the late stage, there was a period of erosion and weight loss of the microspheres. The degradation was much slower for polymers with a higher molecular mass. The polylactide degradation showed good regularity.

  2. Labelling of silica microspheres with fluorescent lanthanide-doped LaF{sub 3} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yong [Division of Bioengineering, Faculty of Engineering, National University of Singapore, 117576, Singapore (Singapore); Lu Meihua [Division of Bioengineering, Faculty of Engineering, National University of Singapore, 117576, Singapore (Singapore)

    2007-07-11

    Fluorescent microspheres have been demonstrated to be useful in a variety of biological applications. Fluorescent silica or polymer microspheres have been produced by incorporation of chromophores into the microspheres, which usually produces microspheres with nonuniform sizes and reduced fluorescence. Here we present a simple and straightforward method to produce silica microspheres with fluorescent lanthanide-doped LaF{sub 3} nanocrystals grown on the surface. LaF{sub 3} nanocrystals are in situ grown on silica microspheres of different sizes to form a raspberry-like structure. The microspheres exhibit strong fluorescence and the colour could be altered by changing the lanthanide ions doped in LaF{sub 3} nanocrystals.

  3. Preparation of recombinant human bone morphogenetic protein-2 loaded dextran-based microspheres and their characteristics

    Institute of Scientific and Technical Information of China (English)

    Fa-ming CHEN; Zhi-fen WU; Qin-tao WANG; Hong WU; Yong-jie ZHANG; Xin NIE; Yan JIN

    2005-01-01

    Aim: To prepare new pharmaceutical forms with sustained delivery properties of recombinant human bone morphogenetic protein-2 (rhBMP2) for tissue engineering and guided tissue regeneration (GTR) use. Methods: rhBMP2-1oaded dextranbased hydrogel microspheres (rhBMP2-MPs), which aimed to keep rhBMP2 bioactivity and to achieve long-term sustained release of rhBMP2, were prepared by double-phase emulsified condensation polymerization. The physical, chemical performances and biological characteristics of those microspheres were studied both in vitro and in vivo. Results: The microspheres' average diameter was 30.33±4.32 μm with 75.4% ranging from 20 μm to 40 μm and the drug loading and encapsulation efficiency were 7.82% and 82.25%, respectively. The rhBMP2-releasing profiles in vitro showed that rhBMP2 release could be maintained more than 10 d. The rhBMP2-MPs, with good swelling and biodegradation behavior,could be kept for 6 months at below 4 ℃ without significant characteristic change or bioactivity loss. Cytology studies showed that rhBMP2-MPs could promote the proliferation of periodontal ligament cells (PDLCs) approximately 10 d, while the bioactivity of concentrated rhBMP2 solution could keep no more than 3 d.Scanning electron microscope showed that rhBMP2-MPs could be enchased into the porous structure of calcium phosphate ceremic (CPC) and the eugonic growth of PDLCs in CPC/rhBMP2-MPs scaffolds. Animal experiments indicated that using CPC/rhBMP2-MPs scaffolds could gain more periodontal tissue regeneration than using rhBMP2 compound firsthand with CPC (CPC/rhBMP2). Conclusion:By encapsulating rhBMP2 into dextran-based microspheres, a small quantity of rhBMP2 could achieve equivalent effects to the concentrated rhBMP2 solution and at the same time, could prolong rhBMP2 retention both in vitro and in vivo.

  4. Microwire formation based on dielectrophoresis of electroless gold plated polystyrene microspheres

    Institute of Scientific and Technical Information of China (English)

    Jiang Hong-Yuan; Ren Yu-Kun; Tao Ye

    2011-01-01

    Microspheres coated with a perfectly conductive surface have many advantages in the applications of biosensors and micro-electromechanical systems. Polystyrene microspheres with the diameter of 10 μm were coated with a 50 nmthick gold layer using an electroless gold plating approach. Dielectrophoresis (DEP) for bare microspheres and shelled microspheres was theoretically analysed and the real part of the Clausius-Mossotti factor was calculated for the two kinds of microspheres. The experiments on the dielectrophoretic characterisation of the uncoated polystyrene microspheres and gold coated polystyrene microspheres (GCPMs) were carried out. Experimental results showed that the gold coated polystyrene microspheres were only acted by a positive dielectrophoretic force when the frequency was below 40M Hz,while the uncoated polystyrene microspheres were governed by a negative dielectrophoretic force in this frequency range.The gold coated polystyrene microspheres were exploited to form the microwire automatically according to their stable dielectrophoretic and electric characterisations.

  5. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Energy Technology Data Exchange (ETDEWEB)

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A.; Brown, Gilbert M.

    2017-04-11

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.

  6. Stochastic porous media equations

    CERN Document Server

    Barbu, Viorel; Röckner, Michael

    2016-01-01

    Focusing on stochastic porous media equations, this book places an emphasis on existence theorems, asymptotic behavior and ergodic properties of the associated transition semigroup. Stochastic perturbations of the porous media equation have reviously been considered by physicists, but rigorous mathematical existence results have only recently been found. The porous media equation models a number of different physical phenomena, including the flow of an ideal gas and the diffusion of a compressible fluid through porous media, and also thermal propagation in plasma and plasma radiation. Another important application is to a model of the standard self-organized criticality process, called the "sand-pile model" or the "Bak-Tang-Wiesenfeld model". The book will be of interest to PhD students and researchers in mathematics, physics and biology.

  7. Characteristics of porous zirconia coated with hydroxyapatite as human bones

    Indian Academy of Sciences (India)

    V V Narulkar; S Prakash; K Chandra

    2007-08-01

    Since hydroxyapatite has excellent biocompatibility and bone bonding ability, porous hydroxyapatite ceramics have been intensively studied. However, porous hydroxyapatite bodies are mechanically weak and brittle, which makes shaping and implantation difficult. One way to solve this problem is to introduce a strong porous network onto which hydroxyapatite coating is applied. In this study, porous zirconia and alumina-added zirconia ceramics were prepared by ceramic slurry infiltration of expanded polystyrene bead compacts, followed by firing at 1500°C. Then slurry of hydroxyapatite–borosilicate glass mixed powder was used to coat the porous ceramics, followed by firing at 1200°C. The porous structures without the coating had high porosities of 51–69%, high pore interconnectivity, and sufficiently large pore window sizes (300–500 m). The porous ceramics had compressive strengths of 5.3∼36.8 MPa, favourably comparable to the mechanical properties of cancellous bones. In addition, porous hydroxyapatite surface was formed on the top of the composite coating, whereas a borosilicate glass layer was found on the interface. Thus, porous zirconia-based ceramics were modified with a bioactive composite coating for biomedical applications.

  8. PREPARATION AND CHARACTERIZATION OF TRAMADOL HYDROCHLORIDE MICROSPHERES

    Directory of Open Access Journals (Sweden)

    Patel Keyur

    2015-10-01

    Full Text Available Tramadol HCl was microencapsulated with Ethylcellulose using multiple emulsion solvent evaporation method. A 32 factorial design employed to study the effect of drug: polymer ratio and volume of External phase (1% PVA on % yield, % encapsulation efficiency, particle size, % drug release rate. The drug: polymer ratio and volume of continuous phase were significant effect on % yield, % entrapment efficiency, particle size, % drug release rate. % drug release was Biphasic system first initially bursting effect and finally sustained. Higher Percentage yield (77.4% and Higher Percentage Encapsulation Efficiency(31.1% were observed in Batch EC3. All the microspheres were spherical in nature its surface was smooth observed in SEM report.

  9. Subcutaneous Construction of Engineered Adipose Tissue with Fat Lobule-Like Structure Using Injectable Poly-Benzyl-L-Glutamate Microspheres Loaded with Adipose-Derived Stem Cells.

    Directory of Open Access Journals (Sweden)

    Wentao Sun

    Full Text Available Porous microcarriers were fabricated from synthesized poly(γ-benzyl-L-glutamate (PBLG polymer to engineer adipose tissue with lobule-like structure via the injectable approach. The adipogenic differentiation of human adipose-derived stem cells (hASCs seeded on porous PBLG microcarriers was determined by adipogenic gene expression and glycerol-3-phosphate dehydrogenase enzyme activity. In vitro adipogenic cultivation was performed for 7 days, and induced hASC/PBLG complex (Adi-ASC/PBLG group was subcutaneously injected into nude mice. Injections of PBLG microcarriers alone (PBLG group and non-induced hASC/PBLG complex (ASC/PBLG group served as controls. Newly formed tissues were harvested after 4 and 8 weeks. Generation of subcutaneous adipose tissue with typical lobule-like structure separated by fibrous septa was observed upon injection of adipogenic-induced hASC/microsphere complex. Adipogenesis significantly increased in the Adi-ASC/PBLG group compared with the control groups. The angiogenesis in the engineered adipose tissue was comparable to that in normal tissue as determined by capillary density and luminal diameter. Cell tracking assay demonstrated that labeled hASCs remained detectable in the neo-generated tissues 8 weeks post-injection using green fluorescence protein-labeled hASCs. These results indicate that adipose tissue with typical lobule-like structure could be engineered using injectable porous PBLG microspheres loaded with adipogenic-induced hASCs.

  10. Subcutaneous Construction of Engineered Adipose Tissue with Fat Lobule-Like Structure Using Injectable Poly-Benzyl-L-Glutamate Microspheres Loaded with Adipose-Derived Stem Cells.

    Science.gov (United States)

    Sun, Wentao; Fang, Jianjun; Yong, Qi; Li, Sufang; Xie, Qingping; Yin, Jingbo; Cui, Lei

    2015-01-01

    Porous microcarriers were fabricated from synthesized poly(γ-benzyl-L-glutamate) (PBLG) polymer to engineer adipose tissue with lobule-like structure via the injectable approach. The adipogenic differentiation of human adipose-derived stem cells (hASCs) seeded on porous PBLG microcarriers was determined by adipogenic gene expression and glycerol-3-phosphate dehydrogenase enzyme activity. In vitro adipogenic cultivation was performed for 7 days, and induced hASC/PBLG complex (Adi-ASC/PBLG group) was subcutaneously injected into nude mice. Injections of PBLG microcarriers alone (PBLG group) and non-induced hASC/PBLG complex (ASC/PBLG group) served as controls. Newly formed tissues were harvested after 4 and 8 weeks. Generation of subcutaneous adipose tissue with typical lobule-like structure separated by fibrous septa was observed upon injection of adipogenic-induced hASC/microsphere complex. Adipogenesis significantly increased in the Adi-ASC/PBLG group compared with the control groups. The angiogenesis in the engineered adipose tissue was comparable to that in normal tissue as determined by capillary density and luminal diameter. Cell tracking assay demonstrated that labeled hASCs remained detectable in the neo-generated tissues 8 weeks post-injection using green fluorescence protein-labeled hASCs. These results indicate that adipose tissue with typical lobule-like structure could be engineered using injectable porous PBLG microspheres loaded with adipogenic-induced hASCs.

  11. Validation of a cage implant system for assessing in vivo performance of long-acting release microspheres.

    Science.gov (United States)

    Doty, Amy C; Hirota, Keiji; Olsen, Karl F; Sakamoto, Naoya; Ackermann, Rose; Feng, Meihua R; Wang, Yan; Choi, Stephanie; Qu, Wen; Schwendeman, Anna; Schwendeman, Steven P

    2016-12-01

    Here we describe development of a silicone rubber/stainless steel mesh cage implant system, much like that used to assess biocompatibility of biomaterials [1], for easy removal of injectable polymer microspheres in vivo. The sterile cage has a type 316 stainless steel mesh size (38 μm) large enough for cell penetration and free fluid flow in vivo but small enough for microsphere retention, and a silicone rubber shell for injection of the microspheres. Two model drugs, the poorly soluble steroid, triamcinolone acetonide, and the highly water-soluble luteinizing hormone-releasing hormone (LHRH) peptide superagonist, leuprolide, were encapsulated in PLGA microspheres large enough (63-90 μm) to be restrained by the cage implant in vivo. The in vitro release from both formulations was followed by ultra-performance liquid chromatography (UPLC) with and without the cage in a standard release media, PBS pH 7.4 + 0.02% Tween 80 + 0.05% sodium azide, at 37 °C. Pharmacokinetics (PK) in rats was assessed after SC injection or SC in-cage implantation of microspheres with plasma analysis by LC-MS/MS or EIA. Tr-A and leuprolide in vitro release was largely unaffected after the initial burst irrespective of the cage or test tube incubation vessel and release was much slower than observed in vivo for both drugs. Moreover, Tr-A and leuprolide pharmacokinetics with and without the cage were highly similar during the 2-3 week release duration before a significant inflammatory response was caused by the cage implant. Hence, the PK-validated cage implant provides a simple means to recover and evaluate the microsphere drug carriers in vivo during a time window of at least a few weeks in order to characterize the polymer microsphere release and erosion behavior in vivo. This approach may facilitate development of mechanism-based in vitro/in vivo correlations and enable development of more accurate and useful in vitro release tests. Copyright © 2016 Elsevier Ltd. All

  12. Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures

    Science.gov (United States)

    Zhang, Feng; Zhang, Yu; Song, Shuyan; Zhang, Hongjie

    2011-10-01

    Mesoporous hollow TiO2 microspheres with controlled size and hierarchical nanostructures are designed from a process employing in suit template-assisted and hydrothermal methods. The results show that the hollow microspheres composed of mesoporous nanospheres possess very stable reversible capacity of 184 mAh g-1 at 0.25C and exhibit extremely high power of 122 mAh g-1 at the high rate of 10C. The superior high-rate and high-capacity performance of the sample is attributed to the efficient hierarchical nanostructures. The hollow structure could shorten the diffusion length for lithium ion in the microspheres. The large mesoporous channels between the mesoporous nanospheres provide an easily-accessed system which facilitates electrolyte transportation and lithium ion diffusion within the electrode materials. The electrolyte, flooding the mesoporous channels, can also lead to a high electrolyte/electrode contact area, facilitating transport of lithium ions across the electrolyte/electrode interface. The small mesopores in the meosporous nanospheres can make the electrolyte and lithium ion further diffuse into the interior of electrode materials and increase electrolyte/electrode contact area. The small nanoparticles can also ensure high reversible capacity.

  13. Carbon Hollow Microspheres with a Designable Mesoporous Shell for High-Performance Electromagnetic Wave Absorption.

    Science.gov (United States)

    Xu, Hailong; Yin, Xiaowei; Zhu, Meng; Han, Meikang; Hou, Zexin; Li, Xinliang; Zhang, Litong; Cheng, Laifei

    2017-02-22

    In this work, mesoporous carbon hollow microspheres (PCHMs) with designable mesoporous shell and interior void are constructed by a facile in situ stöber templating approach and a pyrolysis-etching process. The PCHMs are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, Raman spectroscopy, and nitrogen adsorption and desorption system. A uniform mesoporous shell (pore size 4.7 nm) with a thickness of 55 nm and a cavity size of 345 nm is realized. The composite of paraffin mixed with 20 wt % PCHMs exhibits a minimum reflection coefficient (RCmin) of -84 dB at 8.2 GHz with a sample thickness of 3.9 mm and an effective absorption bandwidth (EAB) of 4.8 GHz below -10 dB (>90% electromagnetic wave is attenuated). Moreover, the composite of phenolic resin mixed with 20 wt % PCHMs exhibits an ultrawide EAB of 8 GHz below -10 dB with a thinner thickness of 2.15 mm. Such excellent electromagnetic wave absorption properties are ascribed to the large carbon-air interface in the mesoporous shell and interior void, which is favorable for the matching of characteristic impedance as compared with carbon hollow microspheres and carbon solid microspheres. Considering the excellent performance of PCHMs, we believe the as-fabricated PCHMs can be promising candidates as highly effective microwave absorbers, and the design philosophy can be extended to other spherical absorbers.

  14. Constructed ILs coated porous magnetic nickel cobaltate hexagonal nanoplates sensing materials for the simultaneous detection of cumulative toxic metals.

    Science.gov (United States)

    Dong, Yuanyuan; Zhang, Lei

    2017-03-18

    The different morphologies of magnetic nickel cobaltate (NiCo2O4) electrocatalysts, consisting of nanoparticles (NiCo2O4-N), nanoplates (NiCo2O4-P) and microspheres (NiCo2O4-S) were fabricated. It was found that the electrocatalytic properties of the sensing materials were strongly dependent on morphology and specific surface area. The porous NiCo2O4 hexagonal nanoplates coupled with ILs as modified materials (ILs@NiCo2O4-P) for the simultaneous determination of thallium (Tl(+)), lead (Pb(2+)) and copper (Cu(2+)), exhibited high sensitivity, long-time stability and good repeatability. The enhanced electrocatalytic activity was attributed to relatively large specific surface area, excellent electronic conductivity, and unique porous nanostructure. The analytical performance of the constructed electrode on detection of Tl(+), Pb(2+) and Cu(2+) was examined using differential pulse anodic stripping voltammetry (DPASV). Under optimal conditions, the electrode showed a good linear response to Tl(+), Pb(2+)and Cu(2+) in the concentration range of 0.1-100.0, 0.1-100.0 and 0.05-100.0μg/L, respectively. The detection limits (S/N=3) were 0.046, 0.034 and 0.029μg/L for Tl(+), Pb(2+) and Cu(2+), respectively. The fabricated sensor was successfully applied to detect trace Tl(+), Pb(2+) and Cu(2+) in various water and soil samples with satisfactory results. Hence, this work provided a promising material for electrochemical determination of cumulative toxic metals individually and simultaneously.

  15. Ternary Porous Sulfur/Dual-Carbon Architectures for Lithium/Sulfur Batteries Obtained Continuously and on a Large Scale via an Industry-Oriented Spray-Pyrolysis/Sublimation Method.

    Science.gov (United States)

    Liang, Xin; Kaiser, Mohammad Rejaul; Konstantinov, Konstantin; Tandiono, Richard; Wang, Zhaoxiang; Chen, Chunhua; Liu, Hua-Kun; Dou, Shi-Xue; Wang, Jiazhao

    2016-09-28

    Ternary composites with porous sulfur/dual-carbon architectures have been synthesized by a single-step spray-pyrolysis/sublimation technique, which is an industry-oriented method that features continuous fabrication of products with highly developed porous structures without the need for any further treatments. A double suspension of commercial sulfur and carbon scaffolding particles was dispersed in ethanol/water solution and sprayed at 180 °C using a spray pyrolysis system. In the resultant composites, the sulfur particles were subjected to an ultrashort sublimation process, leading to the development of a highly porous surface, and were meanwhile coated with amorphous carbon, obtained through the pyrolysis of the ethanol, which acts as an adhesive interface to bind together the porous sulfur with the scaffolding carbon particles, to form a ternary composite architecture. This material has an effective conducting-carbon/sulfur-based matrix and interconnected open pores to reduce the diffusion paths of lithium ions, buffer the sulfur volumetric expansion, and absorb electrolyte and polysulfides. Because of the unique chemistry and the structure, the composites show stable cycling performance for 200 cycles and good rate capability of 520 mAh g(-1) at 2 C. This advanced spray-pyrolysis/sublimation method is easy to scale up and shows great potential for commercialization of lithium/sulfur batteries.

  16. Measurements of extrinsic fluorescence in Intralipid and polystyrene microspheres

    Science.gov (United States)

    Du Le, Vinh Nguyen; Nie, Zhaojun; Hayward, Joseph E.; Farrell, Thomas J.; Fang, Qiyin

    2014-01-01

    The fluorescence of Intralipid and polystyrene microspheres with sphere diameter of 1 µm at a representative lipid and microsphere concentration for simulation of mucosal tissue scattering has not been a subject of extensive experimental study. In order to elucidate the quantitative relationship between lipid and microsphere concentration and the respective fluorescent intensity, the extrinsic fluorescence spectra between 360 nm and 650 nm (step size of 5 nm) were measured at different lipid concentrations (from 0.25% to 5%) and different microsphere concentrations (0.00364, 0.0073, 0.0131 spheres per cubic micrometer) using laser excitation at 355 nm with pulse energy of 2.8 µJ. Current findings indicated that Intralipid has a broadband emission between 360 and 650 nm with a primary peak at 500 nm and a secondary peak at 450 nm while polystyrene microspheres have a single peak at 500 nm. In addition, for similar scattering properties the fluorescence of Intralipid solutions is approximately three-fold stronger than that of the microsphere solutions. Furthermore, Intralipid phantoms with lipid concentrations ~2% (simulating the bottom layer of mucosa) produce up to seven times stronger fluorescent emission than phantoms with lipid concentration ~0.25% (simulating the top layer of mucosa). The fluoresence decays of Intralipid and microsphere solutions were also recorded for estimation of fluorescence lifetime. PMID:25136497

  17. Insulin delivery through nasal route using thiolated microspheres.

    Science.gov (United States)

    Nema, Tarang; Jain, Ashish; Jain, Aviral; Shilpi, Satish; Gulbake, Arvind; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    The aim of the present study was to investigate the potential of developed thiolated microspheres for insulin delivery through nasal route. In the present study, cysteine was immobilized on carbopol using EDAC. A total of 269.93 µmol free thiol groups per gram polymer were determined. The prepared nonthiolated and thiolated microspheres were studied for particle shape, size, drug content, swellability, mucoadhesion and in vitro insulin release. The thiolated microspheres exhibited higher mucoadhesion due to formation of covalent bonds via disulfide bridges with the mucus gel layer. Drug permeation through goat nasal mucosa of nonthiolated and thiolated microspheres were found as 52.62 ± 2.4% and 78.85 ± 3.1% in 6 h, respectively. Thiolated microspheres bearing insulin showed better reduction in blood glucose level (BGL) in comparison to nonthiolated microspheres as 31.23 ± 2.12% and 75.25 ± 0.93% blood glucose of initial BGL were observed at 6 h after nasal delivery of thiolated and nonthiolated microspheres in streptozotocin-induced diabetic rabbits.

  18. Bioavailability enhancement of verapamil HCl via intranasal chitosan microspheres.

    Science.gov (United States)

    Abdel Mouez, Mamdouh; Zaki, Noha M; Mansour, Samar; Geneidi, Ahmed S

    2014-01-23

    Chitosan microspheres are potential drug carriers for maximizing nasal residence time, circumventing rapid mucociliary clearance and enhancing nasal absorption. The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres of verapamil hydrochloride (VRP) for intranasal delivery as an alternative to oral VRP which suffers low bioavailability (20%) due to extensive first pass effect. The microspheres were produced using a spray-drying and precipitation techniques and characterized for morphology (scanning electron microscopy), particle size (laser diffraction method), drug entrapment efficiency, thermal behavior (differential scanning calorimetry) and crystallinity (X-ray diffractometric studies) as well as in vitro drug release. Bioavailability of nasal VRP microspheres was studied in rabbits and the results were compared to those obtained after nasal, oral and intravenous administration of VRP solution. Results demonstrated that the microspheres were spherical with size 21-53 μm suitable for nasal deposition. The spray-drying technique was superior over precipitation technique in providing higher VRP entrapment efficiency and smaller burst release followed by a more sustained one over 6h. The bioavailability study demonstrated that the nasal microspheres exhibited a significantly higher bioavailability (58.6%) than nasal solution of VRP (47.8%) and oral VRP solution (13%). In conclusion, the chitosan-based nasal VRP microspheres are promising for enhancing VRP bioavailability by increasing the nasal residence time and avoiding the first-pass metabolism of the drug substance. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Solvothermal synthesis and photocatalytic properties of NiO ultrathin nanosheets with porous structure

    Science.gov (United States)

    Qing, Zhang; Haixia, Liu; Huali, Li; Yu, Liu; Huayong, Zhang; Tianduo, Li

    2015-02-01

    Hierarchical NiO microspheres, composed of ultrathin nanosheets with porous structure, are prepared through a facile solvothermal route followed by a calcination process. First, the precursor Ni3(NO3)2(OH)4 hierarchical architectures assembled by irregular nanosheets were synthesized through urea assisted precipitation. Second, the NiO hierarchical architecture was obtained from the precursor by a simple calcination procedure without changing their morphologies. The resultant products were characterized by XRD, SEM, TEM, TG, FT-IR and BET analysis techniques. The XRD pattern showed that the sample exhibited a rocksalt cubic phase structure after calcined at 500 °C for 2 h. The SEM and TEM images demonstrated that the as-prepared NiO were microspheres composed of ultrathin nanosheets with porous structure. The catalytic efficiency of the NiO nanomaterials is evaluated by the photocatalytic degradation of methylene blue (MB). The obtained NiO displayed the excellent degradable ability and stable cyclability to MB dye, which may be attributed to its unique hierarchical characteristics: ultrathin-porous microstructure.

  20. Scalable synthesis of mesoporous titania microspheres via spray-drying method.

    Science.gov (United States)

    Pal, Manas; Wan, Li; Zhu, Yongheng; Liu, Yupu; Liu, Yang; Gao, Wenjun; Li, Yuhui; Zheng, Gengfeng; Elzatahry, Ahmed A; Alghamdi, Abdulaziz; Deng, Yonghui; Zhao, Dongyuan

    2016-10-01

    Mesoporous TiO2 has several potential applications due to its unique electronic and optical properties, although its structures and morphologies are typically difficult to tune because of its uncontrollable and fast sol-gel reaction. In this study we have coupled the template-directed-sol-gel-chemistry with the low-cost, scalable, and environmentally benign aerosol (spray-drying) one-pot preparation technique for the fabrication of hierarchically mesoporous TiO2 microspheres and Fe3O4@mesoporous TiO2-x microspheres in a large scale. Parameters during the pre-hydrolysis and spray-drying treatment were varied to successfully control the bead diameter, morphology, monodispersity, surface area and pore size for improving their effectiveness for better application. Unlike to the previous aerosol synthetic approaches, where mainly quite a high temperature gradient with the strict control of spray-drying precursor concentration is implied, our strategy is lying on comparatively low drying temperature with an additional post-ultrasonication (further hydrolysis and condensation) route of the pre-calcined TiO2 samples. As-synthesized mesoporous microspheres have a size distribution from 500nm to 5μm, specific surface areas ranging from 150 to 162m(2)g(-1) and mean pore sizes of several nanometers (4-6nm). Further Fe3O4@mesoporous TiO2-x microspheres were observed to show remarkable selective phosphopeptide-enrichment activity which might have significant importance in disease diagnosis and other biomedical applications.

  1. A Radically New Method for Hydrogen Storage in Hollow Glass Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    James E. Shelby; Matthew M. Hall; Fabienne C. Raszewski

    2007-08-31

    Photo-induced hydrogen diffusion has been applied to the problem of storage of high pressure hydrogen in hollow glass microspheres. Results of this study indicate that this phenomenon can be used to provide a high mass efficiency, safe, cheap, non-toxic method for storage of high pressure hydrogen. The photo-induced response is immediate upon exposure to infrared light for hollow glass microspheres doped with iron, nickel, or cobalt oxide, which is consistent with previous results for transition metal oxide-doped bulk glass samples. This effect is not observed for HGMS which do not contain these transition metal oxide, where the slight release of hydrogen observed occurs only by heating from absorption of the light. The initial rate of hydrogen release increases with increasing concentration of the metal oxide and with increasing hydrogen fill pressure within the microspheres. To date, hydrogen storage efficiencies of 2.2 wt% have been obtained, but results suggest that storage values can be increased to at least 6 wt%. Hydrogen losses over a 5 week period are minimal at room temperature in all compositions, with somewhat greater, but acceptable, losses at 50 C. Hollow glass microspheres have been produced from an alkali alkaline earth borosilicate glass containing either 1 or 5 wt% of the oxides of iron, nickel, and cobalt. Photo-driven gas diffusion has been demonstrated for these HGMS. Demonstration of photo-induced diffusion in these samples provides the first proof-of-concept for eventual applications of HGMS for large scale hydrogen storage.

  2. Porous media fluid transport and pore structure

    CERN Document Server

    Dullien, F A L

    1992-01-01

    This book examines the relationship between transport properties and pore structure of porous material. Models of pore structure are presented with a discussion of how such models can be used to predict the transport properties of porous media. Portions of the book are devoted to interpretations of experimental results in this area and directions for future research. Practical applications are given where applicable, and are expected to be useful for a large number of different fields, including reservoir engineering, geology, hydrogeology, soil science, chemical process engineering, biomedica

  3. Magnetic Carbon Microspheres as a Reusable Adsorbent for Sulfonamide Removal from Water

    Science.gov (United States)

    Dai, Kewei; Wang, Fenghe; Jiang, Wei; Chen, Yajun; Mao, Jing; Bao, Jian

    2017-09-01

    Novel reusable magnetic carbon microspheres (MCMs) were prepared by hydrothermal method with glucose as carbon source and Fe3O4 nanoparticles as magnetic raw materials. And adsorption performance of MCMs for sulfonamide removal from water was investigated in detail. The results indicated that the calcination temperature and calcination time had significant effects on the surface area and its volume porous of MCMs. When MCMs were calcined in 600 °C for 1 h, the surface area and volume porous of MCMs were 1228 m2/g and 0.448 m3/g, respectively. The adsorption results showed that the adsorption data fitted well with the Langmuir isotherm model and followed pseudo-second-order kinetics. When the pH value was changed from 4.0 to 10.0, the adsorption capacity of MCMs for sulfonamide was decreased from 24.6 to 19.2 mg/g. The adsorption capacity of as-synthesized MCMs achieved 18.31 mg/g after it was reused four times, which exhibited a desirable adsorption capacity and reusability.

  4. Magnetic Carbon Microspheres as a Reusable Adsorbent for Sulfonamide Removal from Water.

    Science.gov (United States)

    Dai, Kewei; Wang, Fenghe; Jiang, Wei; Chen, Yajun; Mao, Jing; Bao, Jian

    2017-09-06

    Novel reusable magnetic carbon microspheres (MCMs) were prepared by hydrothermal method with glucose as carbon source and Fe3O4 nanoparticles as magnetic raw materials. And adsorption performance of MCMs for sulfonamide removal from water was investigated in detail. The results indicated that the calcination temperature and calcination time had significant effects on the surface area and its volume porous of MCMs. When MCMs were calcined in 600 °C for 1 h, the surface area and volume porous of MCMs were 1228 m(2)/g and 0.448 m(3)/g, respectively. The adsorption results showed that the adsorption data fitted well with the Langmuir isotherm model and followed pseudo-second-order kinetics. When the pH value was changed from 4.0 to 10.0, the adsorption capacity of MCMs for sulfonamide was decreased from 24.6 to 19.2 mg/g. The adsorption capacity of as-synthesized MCMs achieved 18.31 mg/g after it was reused four times, which exhibited a desirable adsorption capacity and reusability.

  5. Autonomic shutdown of lithium-ion batteries using thermoresponsive microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Baginska, Marta; White, Scott R. [306 Talbot Laboratory, Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL (United States); Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL (United States); Blaiszik, Benjamin J.; Sottos, Nancy R. [Department of Materials Science and Engineering, Materials Science and Engineering Building, University of Illinois Urbana-Champaign, Urbana, IL (United States); Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL (United States); Merriman, Ryan J. [306 Talbot Laboratory, Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL (United States); Moore, Jeffrey S. [Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL (United States)

    2012-05-15

    Autonomic, thermally-induced shutdown of Lithium-ion (Li-ion) batteries is demonstrated by incorporating thermoresponsive polymer microspheres (ca. 4 {mu}m) onto battery anodes or separators. When the internal battery environment reaches a critical temperature, the microspheres melt and coat the anode/separator with a nonconductive barrier, halting Li-ion transport and shutting down the cell permanently. Three functionalization schemes are shown to perform cell shutdown: 1) poly(ethylene) (PE) microspheres coated on the anode, 2) paraffin wax microspheres coated on the anode, and 3) PE microspheres coated on the separator. Charge and discharge capacity is measured for Li-ion coin cells containing microsphere-coated anodes or separators as a function of capsule coverage. For PE coated on the anode, the initial capacity of the battery is unaffected by the presence of the PE microspheres up to a coverage of 12 mg cm{sup -2} (when cycled at 1C), and full shutdown (>98% loss of initial capacity) is achieved in cells containing greater than 3.5 mg cm{sup -2}. For paraffin microspheres coated on the anode and PE microspheres coated on the separator, shutdown is achieved in cells containing coverages greater than 2.9 and 13.7 mg cm{sup -2}, respectively. Scanning electron microscopy images of electrode surfaces from cells that have undergone autonomic shutdown provides evidence of melting, wetting, and resolidification of PE into the anode and polymer film formation at the anode/separator interface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Bone regeneration performance of surface-treated porous titanium

    NARCIS (Netherlands)

    Amin Yavari, Saber; Stok, Johan; Chai, Yoke Chin; Wauthle, Ruben; Thamasebi Birgani, Zeinab; Habibovic, Pamela; Mulier, Michiel; Schrooten, Jan; Weimans, Harrie; Zadpoor, Amir Abbas

    2014-01-01

    The large surface area of highly porous titanium structures produced by additive manufacturing can be modified using biofunctionalizing surface treatments to improve the bone regeneration performance of these otherwise bioinert biomaterials. In this longitudinal study, we applied and compared three

  7. Experimental research of MAC modified large stone porous asphalt mixture%MAC改性沥青大粒径透水性沥青混合料试验研究

    Institute of Scientific and Technical Information of China (English)

    王恩东; 张洪亮; 王选仓

    2008-01-01

    In order to improve the road performances of base course made of large stone porous asphalt mixture(LSPM), MAC(multigrade asphalt cement) modified asphalt was used in LSPM, the performances of matrix aphalt, MAC modified asphalt and SBS modified asphalt were compared, the material composition design, construction technology and the road performances of MAC modified LSPM, such as high-temperature stability, anti-fatigue property, permeability and anti-reflective crack property, were studied, and test roads were constructed. Test result shows that the porosity of LSPM is between 13% and 18%, its asphalt membrane is thicker than 12 μm, its modulous is between 400 and 600 MPa, the rut depth of test road opening to traffic for two years is between 4 and 8 mm. Obviously, MAC modified LSPM has better road performances. 4 tabs, 2 figs, 16 refs.%为了提高大粒径透水性沥青混合料(LSPM)基层的路用性能,以MAC改性沥青作为LSPM结合料,对MAC改性沥青、基质沥青和SBS改性沥青的性能进行了对比,提出了MAC改性沥青LSPM高温稳定性、水稳定性、抗疲劳性、渗透性、抗反射裂缝性等路用性能要求,并进行了MAC改性沥青LSPM材料组成设计、施工技术研究和试验路修筑.试验结果表明:MAC改性沥青LSPM空隙率为13%~18%,沥青膜的厚度大于12 μm,模量为400~600 MPa,试验路通车2年后车辙量在4~8 mm之间,这表明MAC改性沥青LSPM具有较高的路用性能.

  8. The in vivo performance of CaP/PLGA composites with varied PLGA microsphere sizes and inorganic compositions.

    Science.gov (United States)

    Hoekstra, Jan Willem M; Ma, Jinling; Plachokova, Adelina S; Bronkhorst, Ewald M; Bohner, Marc; Pan, Juli; Meijer, Gert J; Jansen, John A; van den Beucken, Jeroen J J P

    2013-07-01

    Enrichment of calcium phosphate (CaP) bone substitutes with poly(lactic-co-glycolic acid) (PLGA) microspheres to create porosity overcomes the problem of poor CaP degradation. The degradation of CaP-PLGA composites can be customized by changing the physical and chemical properties of PLGA and/or CaP. However, the effect of the size of dense (solid rather than hollow) PLGA microspheres in CaP has not previously been described. The present study aimed at determining the effect of different dense (i.e. solid) PLGA microsphere sizes (small (S) ~20μm vs. large (L) ~130μm) and of CaP composition (CaP with either anhydrous dicalcium phosphate (DCP) or calcium sulphate dihydrate (CSD)) on CaP scaffold biodegradability and subsequent bone in-growth. To this end mandibular defects in minipigs were filled with pre-set CaP-PLGA implants, with autologous bone being used as a control. After 4weeks the autologous bone group outperformed all CaP-PLGA groups in terms of the amount of bone present at the defect site. On the other hand, at 12weeks substantial bone formation was observed for all CaP-PLGA groups (ranging from 47±25% to 62±15%), showing equal amounts of bone compared with the autologous bone group (82±9%), except for CaP with DCP and large PLGA microspheres (47±25%). It was concluded that in the current study design the difference in PLGA microsphere size and CaP composition led to similar results with respect to scaffold degradation and subsequent bone in-growth. Further, after 12weeks all CaP-PLGA composites proved to be effective for bone substitution.

  9. Preparation of paclitaxel-loaded microspheres with magnetic nanoparticles

    Institute of Scientific and Technical Information of China (English)

    CUI Sheng; SHEN Xiaodong; SHI Ruihua; LIN Benlan; CHEN Ping

    2007-01-01

    The objective of this paper was to prepare paclitaxel-loaded microspheres,a kind of target-orientation anticancer drug.The paclitaxel-loaded microspheres were prepared with magnetic Fe3O4 nanoparticles and taxo1.The morphology was characterized by scanning electron microscopy(SEM),and the average size and the size distribution were determined by a laser-size distributing instrument.High performance liquid chromatography(HPLC)was used to measure the paclitaxel content.Experimental results indicated that the effective drug loading and the entrapment ratio of paclitaxel-loaded microspheres were 1.83% and 92,62%,respectively.

  10. Locomotion of microspheres for imaging and light focusing applications

    CERN Document Server

    Krivitsky, Leonid A; Wang, Zengbo; Lukiyanchuk, Boris

    2013-01-01

    Super-resolution imaging using sub-diffraction field localization by micron sized transparent beads (microspheres) was recently demonstrated [1]. Practical applications in microscopy require control over the positioning of the microspheres. We present a simple method of positioning and controllable movement of a microsphere by using a glass micropipette. This allows sub-diffraction imaging at arbitrary points in three dimensions, as well as the ability to track moving objects. The results are relevant to a broad scope of applications, including sample inspection, and bio-imaging.

  11. Confocal epifluorescence detection for microspheres delivered on disposable microfluidic chip

    Institute of Scientific and Technical Information of China (English)

    Honghua Hu; Xiyun Hou; Guoguang Yang

    2006-01-01

    @@ The laser induced fluorescence (LIF) detection system for 5-μm microspheres delivered on microfluidic chip is presented employing confocal optical scheme. The parameters of the optical system are specifically optimized for single microsphere detection. With the excitation laser spot size of 4.6 μm and optical sectioning power of 27 μm, the lowest concentration detection limit is 0.45 nmol/L, corresponding to only 122 molecules in probe volume. The microsphere detection is carried on successfully with the maximum signal-to-noise ratio (SNR) of 55.7, which provides good detection sensitivity.

  12. Optical properties of metallo-dielectric microspheres in opal structures

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y; Whitehouse, C; Li, Jensen; Tam, Wing Yim; Chan, C T; Sheng Ping [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2003-09-03

    We report the fabrication of opal structure using metallo-dielectric silica microspheres. Mono-dispersed silica microspheres were coated with silver using an electrode-less wet-plating technique. Thin slabs of opal were obtained by assembling the silver-coated microspheres between two glass plates using a forced-packing method. The optical properties of the resulting opal structure were studied in the infrared range. Good agreement is obtained with the predictions of a multiple scattering approach, provided that the silver layer is modelled as a silver composite.

  13. Packaged chalcogenide microsphere resonator with high Q-factor

    Science.gov (United States)

    Wang, Pengfei; Ding, Ming; Lee, Timothy; Senthil Murugan, Ganapathy; Bo, Lin; Semenova, Yuliya; Wu, Qiang; Hewak, Dan; Brambilla, Gilberto; Farrell, Gerald

    2013-04-01

    The fabrication and characterization of a packaged As2S3 microsphere resonator coupled to a tapered fiber using a low refractive index UV-curable polymer are reported. Embedding provides an efficient means to remove the highest order whispering gallery modes in the microsphere resonator, thus cleaning the resonator spectrum. At wavelengths near 1549.5 nm, high-Q modes up to 1.8 × 105 can be efficiently excited in a 110 μm diameter chalcogenide microsphere via evanescent coupling from a 2 μm diameter tapered silica fiber. The device photosensitivity, useful for tuning, is still present and useable after the packaging process.

  14. Porous polymers based on aryleneethynylene building blocks.

    Science.gov (United States)

    Bunz, Uwe H F; Seehafer, Kai; Geyer, Florian L; Bender, Markus; Braun, Ingo; Smarsly, Emanuel; Freudenberg, Jan

    2014-09-01

    Porous conjugated polymers are synthesized by metal-catalyzed coupling reactions. The progress for porous polymers when planar or tetrahedral building blocks are connected by alkyne units into novel materials is highlighted. The most prominent reaction for the buildup of the microporous alkyne-bridged polymers is the Sonogashira reaction, connecting alkynes to aromatic iodides or bromides. The availability of the building blocks and the potency of the Sonogashira reaction allow preparing a large variety of intrinsically porous polymeric materials, in which rigid struts connect multipronged centers. The microporous polymers are used as catalysts and as storage materials for gases and sensors. Postfunctionalization schemes, understanding of structure-property relationships, and the quest for high porosity are pertinent.

  15. Restricted access magnetic core-mesoporous shell microspheres with C8-modified interior pore-walls for the determination of diazepam in rat plasma by LC-MS.

    Science.gov (United States)

    Liu, Xiaodan; Yu, Yingjia; Li, Yan; Ning, Suli; Liu, Tingting; Li, Fajie; Duan, Gengli

    2013-03-15

    In this study, a novel enrichment technique based on magnetic core-mesoporous shell microspheres with C8-modified interior pore-walls (C8-Fe₃O₄@mSiO₂) was successfully developed for the determination of diazepam in rat plasma by LC-MS. Due to the unique properties of the synthesized C8-Fe₃O₄@mSiO₂ microspheres (C8-modified magnetic mesoporous microsphere), small drug molecules like diazepam can enter the mesopore channels and be efficiently absorbed through hydrophobic interaction by interior C8-groups (Octyl functional groups). Large molecules like proteins are excluded from the mesopore channels as a result of size exclusion effect, leading to direct extraction of drug molecules from protein-rich biosmaples such as plasma without any other pretreatment procedure. Moreover, diazepam adsorbed C8-Fe₃O₄@mSiO₂ microspheres could be simply and rapidly isolated through placing a magnet on the bottom of container, and then diazepam could be easily eluted from C8-Fe₃O₄@mSiO₂ microspheres for further LC-MS analysis. Extraction conditions such as amounts of C8-Fe₃O₄@mSiO₂ microspheres added, adsorption time, elution solvent and elution time were investigated. Method validations including linear range, the limit of detection, precision, and recovery were also studied. The results indicated that the proposed method based on C8-Fe₃O₄@mSiO₂ microspheres was simple and accurate for the analysis of diazepam in the rat plasma. And it will provide new ideas for analyzing plasma concentration and pharmacokinetics of similar drugs.

  16. Resurgence flows in porous media

    Science.gov (United States)

    Adler, Pierre; Mityushev, Vladimir

    2010-05-01

    Porous media are generally described by the Darcy equation when the length scales are sufficiently large with respect to the pore scale. This approach is also applicable when the media are heterogeneous, i.e., when permeability varies with space which is the most common case. In addition, real media are very often fractured; for a long time, this complex physical problem has been schematized by the double porosity model devised by Barenblatt. More recently, these fractured media have been addressed with a detailed description of the fractures and of their hydrodynamic interaction with the surrounding porous medium. This approach will be briefly summarized and the main recent progress surveyed (2). There is another situation which occurs frequently in underground studies. One well is connected to a distant well while it is not connected to closer wells. Such a situation can only be understood if there is a direct link between the two connected wells and if this link has little if any hydrodynamic interaction with the porous medium that it crosses. This link can be a fracture or more likely a set of fractures. This phenomenon is called resurgence because of the obvious analogy with rivers which suddenly disappear underground and go out at the ground surface again. Similar ideas have already been developed in other fields. In Physics, random networks limited to nearest neighbors have been recently extended to small world models where distant vertices can be related directly by a link. The electrical testing of porous media by electrical probes located at the walls (electrical tomography) has been used frequently in Geophysics since it is a non-invasive technique; this classical technique corresponds exactly to the situation addressed here from a different perspective. Media with resurgences consist of a double structure (3). The first one which is continuous is described by Darcy law as usual. The second one models the resurgences by capillaries with impermeable walls

  17. Self-assembled mesoporous hierarchical-like In2S3 hollow microspheres composed of nanofibers and nanosheets and their photocatalytic activity.

    Science.gov (United States)

    Rengaraj, Selvaraj; Venkataraj, Selvaraj; Tai, Cheuk-wai; Kim, Younghun; Repo, Eveliina; Sillanpää, Mika

    2011-05-03

    Novel template-free hierarchical-like In(2)S(3) hollow microspheres were synthesized using thiosemicarbazide (NH(2)NHCSNH(2)) as both a sulfur source and a capping ligand in a ethanol/water system. In this study, we demonstrate that several process parameters, such as the reaction time and precursor ratio, strongly influence the morphology of the final product. The In(NO(3))(3)/thiosemicarbazide ratios were found to effectively play crucial roles in the morphologies of the hierarchical-like In(2)S(3) hollow microsphere nanostructure. With the ratios increasing from two to four, the In(2)S(3) crystals exhibited almost spherical morphologies. The synthesized products have been characterized by a variety of methods, including X-ray powder diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffused reflectance spectroscopy (UV-vis DRS). XRD analysis confirmed the tetragonal structure of the In(2)S(3) hollow microspheres. The products show complex hierarchical structures assembled from nanoscale building blocks. The morphology evolution can be realized on both outside (surface) and inside (hollow cavity) the microsphere. The surface area analysis showed that the porous In(2)S(3) possesses a specific surface area of 108 m(2)/g and uniform distribution of pore sizes corresponding to the size of pores resulting from the self-assembled structures with flakes. The optical properties of In(2)S(3) were also investigated by UV-vis DRS, which indicated that our In(2)S(3) microsphere samples possess a band gap of ∼1.96 eV. Furthermore, the photocatalytic activity studies revealed that the synthesized In(2)S(3) hollow microspheres exhibit an excellent photocatalytic performance in rapidly degrading aqueous methylene blue dye solution under visible light irradiation. These

  18. Method of porous diamond deposition on porous silicon

    Science.gov (United States)

    Baranauskas, Vitor; Peterlevitz, Alfredo C.; Chang, Dahge C.; Durrant, Steven F.

    2001-12-01

    In this paper, we discuss the experimental results of the fabrication of porous diamond/porous silicon and porous diamond structures by chemical vapor deposition of diamond over a skeleton of porous silicon, replicating the porous surface geometry around the Si pores and also creating new porous diamond structures. Scanning electron microscopy (SEM) revealed that the diamond nuclei are deposited on the top of the porous silicon skeleton, forming isolated grains in the first nucleation stages, and then growing like the usual structure of most ceramic materials, making a self-sustained porous diamond structure. Raman spectroscopy revealed that the diamond films are of good quality, close to that of diamond films grown on crystalline silicon.

  19. Preparation of Hollow Silica Microspheres via Poly(N-isopropylacrylamide)

    Institute of Scientific and Technical Information of China (English)

    Mo-zhen Wang; Yu-chen Chen; Xue-ping Ge; Xue-wu Ge

    2012-01-01

    Core-shell structured SiO2/poly(N-isopropylacrylamide) (SiO2/PNIPAM) microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl orthosilicate (TEOS) on the surface of PNIPAM template at 50 ℃.The PNIPAM template can be easily removed by water at room temperature so that SiO2 hollow microspheres were finally obtained.The transmission electron microscope and scanning electron microscope observations indicated that SiO2 hollow microspheres with an average diameter of 150 nm can be formed only if there are enough concentration of PNIPAM and TEOS,and the hydrolysis time of TEOS.FTIR analysis showed that part of PNIPAM remained on the wall of SiO2 because of the strong interaction between PNIPAM and silica.This work provides a clean and efficient way to prepare hollow microspheres.

  20. MULTI-SCALE STRUCTURES IN EMULSION AND MICROSPHERE COMPLEX SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Guanghui Ma; Fangling Gong; Guohua Hu; Dongxia Hao; Rong Liu; Renwei Wang

    2005-01-01

    Multi-scale structures involved in emulsion and microsphere complex systems are presented and discussed. The stability and spatio-temporal structures of emulsions, as well as nano-structures formed on the surface of microspheres after polymerization, are affected by the molecular emulsifier/stabilizer structures and the adsorbed emulsifier/stabilizer nano-structures on the oil/water interface. The broad size distribution and variation of surface features of droplets are responsible for variations of the adsorbed emulsifier/stabilizer structures and the stability of the emulsions.On the other hand, preparation of a uniformly sized emulsion and employment of a combined emulsifier/stabilizer system can preserve the stability of the emulsions and microspheres. The above phenomena should be modeled by a multiscale method, in order to maintain the stability of individual emulsion systems and realize the desired nano-structures of microspheres by choosing adequate emulsifier/stabilizer and experimental parameters.

  1. Super-Resolution Real Imaging in Microsphere-Assisted Microscopy

    Science.gov (United States)

    Wang, Feifei; Li, Yi; Jia, Boliang; Liu, Lianqing; Li, Wen Jung

    2016-01-01

    Microsphere-assisted microscopy has received a lot of attention recently due to its simplicity and its capability to surpass the diffraction limit. However, to date, sub-diffraction-limit features have only been observed in virtual images formed through the microspheres. We show that it is possible to form real, super-resolution images using high-refractive index microspheres. Also, we report on how changes to a microsphere’s refractive index and size affect image formation and planes. The relationship between the focus position and the additional magnification factor is also investigated using experimental and theoretical methods. We demonstrate that such a real imaging mode, combined with the use of larger microspheres, can enlarge sub-diffraction-limit features up to 10 times that of wide-field microscopy’s magnification with a field-of-view diameter of up to 9 μm. PMID:27768774

  2. XPS analysis of aluminosilicate microspheres bioactivity tested in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Todea, M.; Vanea, E. [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania); Bran, S. [University of Medicine and Pharmacy “Iuliu Haţieganu”, Department of Cranio-Maxillofacial Surgery, 400029 Cluj-Napoca (Romania); Berce, P. [Technical University of Cluj-Napoca, Faculty of Machine Building and National Centre of Rapid Prototyping, 400641 Cluj-Napoca (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania)

    2013-04-01

    The study aims to characterize surface properties of aluminosilicate microspheres incorporating yttrium, with potential biomedical applications. Micrometric particles of spherical shape were obtained by spray drying method. The behavior of aluminosilicate microspheres without yttrium and with yttrium was investigated under in vitro conditions, by seven days incubation in simulated body fluid (SBF). The surface elemental composition and the atomic environments on outermost layer of the microspheres, prior to and after incubation in SBF were evaluated by X-ray photoelectron spectroscopy (XPS) in order to investigate their bioactivity. The results were analyzed to underline the effect of yttrium addition on surface properties of the aluminosilicate microspheres and implicitly on the behavior of the samples in simulated body environments.

  3. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  4. Amorphous and nanostructured silica and aluminosilicate spray-dried microspheres

    Science.gov (United States)

    Todea, M.; Turcu, R. V. F.; Frentiu, B.; Tamasan, M.; Mocuta, H.; Ponta, O.; Simon, S.

    2011-08-01

    Amorphous silica and aluminosilicate microspheres with diameters in the 0.1-20 μm range were produced by spray drying method. SEM, TEM and AFM images showed the spherical shape of the obtained particles. Based on thermal analysis data, several heat treatments have been applied on the as-prepared samples in order to check the amorphous state stability of the microspheres and to develop nanosized crystalline phases. As-prepared microspheres remain amorphous up to 1400 °C. By calcination at 1400 °C, cristobalite type nanocrystals are developed on silica sample, while in aluminosilicate sample first are developed mullite type nanocrystals and only after prolonged treatment are developed also cristobalite type nanocrystals. 29Si and 27Al MAS NMR results show that the local order around aluminum and silicon atoms strongly depend on the thermal history of the microspheres.

  5. Resonant microsphere gyroscope based on a double Faraday rotator system.

    Science.gov (United States)

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  6. Development and characterization of ethylcellulose based microsphere for sustained release of nifedipine$

    Institute of Scientific and Technical Information of China (English)

    Patitapabana Parida; Subash Chandra Mishra; Subhashree Sahoo; Ajit Behera; Bibhukalyan Prasad Nayak

    2016-01-01

    This article introduced the work of ethylcellulose based polymeric microsphere loaded with nifedipine for reduction in frequency of administration with low solubility in aqueous medium and high rate of absorption in the stomach. The non-aqueous polymeric suspension was put dropwise into an aqueous medium containing polyvinyl alcohol as a surfactant for the synthesis of microsphere by solvent eva-poration. The microspheres were characterized by different techniques, namely, XRD, SEM, and NMR. The formation of microspheres was confirmed by SEM. XRD analysis revealed the semi-crystallinity nature of microspheres. The NMR study indicated the presence of hetero-aromatic nucleus in the microsphere.

  7. Porous La0.6Sr0.4CoO3-δ thin film cathodes for large area micro solid oxide fuel cell power generators

    DEFF Research Database (Denmark)

    Garbayo, A.; Esposito, Vincenzo; Sanna, Simone

    2014-01-01

    Porous La0.6Sr0.4CoO3-δ thin films were fabricated by pulsed laser deposition for being used as a cathode for micro solid oxide fuel cell applications as MEMS power generators. Symmetrical La0.6Sr0.4CoO3-δ/ yttria-stabilized zirconia/La0.6Sr0.4CoO3-δ free-standing membranes were fabricated using ...

  8. Template-free synthesis of hierarchical TiO2 hollow microspheres as scattering layer for dye-sensitized solar cells

    Science.gov (United States)

    Rui, Yichuan; Wang, Linlin; Zhao, Jiachang; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong; Xu, Jingli

    2016-04-01

    Hierarchical TiO2 hollow microspheres were synthesized by a 2-step process consisting of thermal hydrolysis and subsequent solvothermal reaction. Quasi-monodispersed solid TiO2 microspheres aggregated by amorphous particles were firstly obtained by the controlled thermal hydrolysis of titanium sulfate, and then the solid structures transformed to hollow ones and crystallized during the subsequent solvothermal treatment. SEM and TEM images of the samples revealed that the morphological evolution was in perfect accordance with the inside-out Ostwald ripening mechanism. The rich porosity and unique hierarchical hollow structure endow the TiO2 microspheres with a large specific surface area of 108.0 m2 g-1. As an effective anode material for dye-sensitized solar cells, TiO2 hollow microspheres showed good capability of dye adsorption and strong light scattering, leading to a comparable energy conversion efficiency to the commercial 18NR-T transparent titania. Finally, a high efficiency of 7.84% was achieved for the bi-layer DSSC by coating the hollow microspheres on top of the 18NR-T titania as the light scattering layer.

  9. Porous block nanofiber composite filters

    Energy Technology Data Exchange (ETDEWEB)

    Ginley, David S.; Curtis, Calvin J.; Miedaner, Alexander; Weiss, Alan J.; Paddock, Arnold

    2016-08-09

    Porous block nano-fiber composite (110), a filtration system (10) and methods of using the same are disclosed. An exemplary porous block nano-fiber composite (110) includes a porous block (100) having one or more pores (200). The porous block nano-fiber composite (110) also includes a plurality of inorganic nano-fibers (211) formed within at least one of the pores (200).

  10. Preparation of biodegradable microspheres and matrix devices containing naltrexone

    OpenAIRE

    DINARVAND, RASSOUL; Moghadam, Shadi H.; Mohammadyari-Fard, Leyla; Atyabi, Fatemeh

    2003-01-01

    In this study, the use of biodegradable polymers for microencapsulation of naltrexone using solvent evaporation technique is investigated. The use of naltrexone microspheres for the preparation of matrix devices is also studied. For this purpose, poly(L-lactide) (PLA) microspheres containing naltrexone prepared by solvent evaporation technique were compressed at temperatures above the Tg of the polymer. The effect of different process parameters, such as drug/polymer ratio and stirring rate d...

  11. In vitro and in vivo toxicity of magnetic microspheres

    Science.gov (United States)

    Häfeli, Urs O.; Pauer, Gayle J.

    1999-04-01

    The interaction of magnetic microspheres with cells was studied using an in vitro 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (=MTT) assay. Viability and metabolic activity were reduced in all examples. The MTT assay is not recommended for this application due to high variability and non-specificity. Poly(lactic acid) microspheres were further tested in vivo. Intrathecal injection in rats produced no obvious side effects over 12 months.

  12. Multiplexed magnetic microsphere immunoassays for detection of pathogens in foods

    OpenAIRE

    Kim, Jason S.; Chris R Taitt; Ligler, Frances S.; Anderson, George P.

    2010-01-01

    Foodstuffs have traditionally been challenging matrices for conducting immunoassays. Proteins, carbohydrates, and other macromolecules present in food matrices may interfere with both immunoassays and PCR-based tests, and removal of particulate matter may also prove challenging prior to analyses. This has been found true when testing for bacterial contamination of foods using the standard polystyrene microspheres utilized with Luminex flow cytometers. Luminex MagPlex microspheres are encoded ...

  13. CHARACTERIZATION OF CAPTOPRIL-ETHYL CELLULOSE MICROSPHERES BY THERMAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    RakeshGupta

    2010-06-01

    Full Text Available The objective of the present study was to study the physical characterization of Captopril-ethyl cellulose microspheres by thermal analysis such as Differential Scanning Calorimetry (DSC, Differential thermal analysis (DTA and Thermo gravimetry (TG. Drug polymer interaction can directly affect the dosage form stability, drug encapsulation into polymers and dissolution patterns. In this study thermal analysis has been carried out for the physical mixtures and microspheres of captopril and ethyl cellulose prepared by solvent evaporation method.