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Sample records for prepare uniform-sized microsphere

  1. Preparation and characterization of uniform-sized chitosan/silver microspheres with antibacterial activities

    Energy Technology Data Exchange (ETDEWEB)

    An, Jing; Ji, Zhenxing; Wang, Desong, E-mail: dswang06@126.com; Luo, Qingzhi; Li, Xueyan

    2014-03-01

    The chitosan/silver microspheres (CAgMs), which possess effective inhibitory on microorganisms, were prepared by an inverse-emulsification cross-linking method using CS/Ag sol as dispersed phase, whiteruss as continuous phase, and glutaraldehyde as crosslinking agent. The size and shape of CAgMs, greatly affecting their antibacterial activities, were controlled by varying the concentrations of cross-linking agent, emulsifier and CS/Ag colloid. The preparation conditions for obtaining uniform-sized microspheres were optimized. The morphology of CAgMs was characterized by scanning electron microscopy (SEM) and laser particle size analysis. The spherical CAgMs with smooth surface in the mean size of ca. 5 μm exhibited a narrow particle size distribution. Energy Dispersive X-ray spectroscopy (EDX) revealed the elemental composition of the microspheres. Transmission electron micrographs (TEM) and Fourier transform infrared spectroscopy (FTIR) of the microspheres confirmed the formation of silver nanoparticles (AgNPs). The X-ray diffraction (XRD) patterns and UV–Visible diffuse reflectance spectroscopy (UV–vis DRS) of the sample showed that AgNPs with the diameter no more than 20 nm were face-centered cubic crystallites. X-ray photoelectron spectroscopy (XPS) proved that Ag-O bond existed in the microspheres. Thermogravimetric analysis (TGA) showed that the starting decomposition temperature of CAgMs (ca. 260 °C) was much higher than that of CS (ca. 160 °C), suggesting that the as-prepared CAgMs possessed better thermal stability than original CS did. Antimicrobial assays were performed using typical Gram bacteria and fungi. The inhibitory effect indicated that the as-prepared microspheres exerted a stronger antibacterial activity as the concentration of the AgNPs is increasing, and the microspheres in smaller size had much better antibacterial activity than those in the larger size. The antimicrobial mechanism of CAgMs was discussed. - Highlights: • CAgM was

  2. Preparation and characterization of uniform-sized chitosan/silver microspheres with antibacterial activities.

    Science.gov (United States)

    An, Jing; Ji, Zhenxing; Wang, Desong; Luo, Qingzhi; Li, Xueyan

    2014-03-01

    The chitosan/silver microspheres (CAgMs), which possess effective inhibitory on microorganisms, were prepared by an inverse-emulsification cross-linking method using CS/Ag sol as dispersed phase, whiteruss as continuous phase, and glutaraldehyde as crosslinking agent. The size and shape of CAgMs, greatly affecting their antibacterial activities, were controlled by varying the concentrations of cross-linking agent, emulsifier and CS/Ag colloid. The preparation conditions for obtaining uniform-sized microspheres were optimized. The morphology of CAgMs was characterized by scanning electron microscopy (SEM) and laser particle size analysis. The spherical CAgMs with smooth surface in the mean size of ca. 5 μm exhibited a narrow particle size distribution. Energy Dispersive X-ray spectroscopy (EDX) revealed the elemental composition of the microspheres. Transmission electron micrographs (TEM) and Fourier transform infrared spectroscopy (FTIR) of the microspheres confirmed the formation of silver nanoparticles (AgNPs). The X-ray diffraction (XRD) patterns and UV-Visible diffuse reflectance spectroscopy (UV-vis DRS) of the sample showed that AgNPs with the diameter no more than 20 nm were face-centered cubic crystallites. X-ray photoelectron spectroscopy (XPS) proved that AgO bond existed in the microspheres. Thermogravimetric analysis (TGA) showed that the starting decomposition temperature of CAgMs (ca. 260°C) was much higher than that of CS (ca. 160°C), suggesting that the as-prepared CAgMs possessed better thermal stability than original CS did. Antimicrobial assays were performed using typical Gram bacteria and fungi. The inhibitory effect indicated that the as-prepared microspheres exerted a stronger antibacterial activity as the concentration of the AgNPs is increasing, and the microspheres in smaller size had much better antibacterial activity than those in the larger size. The antimicrobial mechanism of CAgMs was discussed. Copyright © 2013 Elsevier B.V. All

  3. Uniform-sized silicone oil microemulsions: preparation, investigation of stability and deposition on hair surface.

    Science.gov (United States)

    Nazir, Habiba; Lv, Piping; Wang, Lianyan; Lian, Guoping; Zhu, Shiping; Ma, Guanghui

    2011-12-01

    Emulsions are commonly used in foods, pharmaceuticals and home-personal-care products. For emulsion based products, it is highly desirable to control the droplet size distribution to improve storage stability, appearance and in-use property. We report preparation of uniform-sized silicone oil microemulsions with different droplets diameters (1.4-40.0 μm) using SPG membrane emulsification technique. These microemulsions were then added into model shampoos and conditioners to investigate the effects of size, uniformity, and storage stability on silicone oil deposition on hair surface. We observed much improved storage stability of uniform-sized microemulsions when the droplets diameter was ≤22.7 μm. The uniform-sized microemulsion of 40.0 μm was less stable but still more stable than non-uniform sized microemulsions prepared by conventional homogenizer. The results clearly indicated that uniform-sized droplets enhanced the deposition of silicone oil on hair and deposition increased with decreasing droplet size. Hair switches washed with small uniform-sized droplets had lower values of coefficient of friction compared with those washed with larger uniform and non-uniform droplets. Moreover the addition of alginate thickener in the shampoos and conditioners further enhanced the deposition of silicone oil on hair. The good correlation between silicone oil droplets stability, deposition on hair and resultant friction of hair support that droplet size and uniformity are important factors for controlling the stability and deposition property of emulsion based products such as shampoo and conditioner. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Preparation of alumina microspheres

    International Nuclear Information System (INIS)

    Santos, W.R. dos; Abrao, A.

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina micro-spheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO 2 , ThO 2 ). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper. (C.L.B.) [pt

  5. Synthesis, characterization and evaluation of uniformly sized core-shell imprinted microspheres for the separation trans-resveratrol from giant knotweed

    International Nuclear Information System (INIS)

    Zhang Zhaohui; Liu Li; Li Hui; Yao Shouzhuo

    2009-01-01

    A novel core-shell molecularly imprinting microspheres (MIMs) with trans-resveratrol as the template molecule; acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, was prepared based on SiO 2 microspheres with surface imprinting technique. These core-shell trans-resveratrol imprinted microspheres were characterized by infrared spectra (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and high performance liquid chromatography (HPLC). The results showed that these core-shell imprinted microspheres, which take on perfect spherical shape with average shell thickness of 150 nm, exhibit especially selective recognition for trans-resveratrol. These imprinted microspheres were applied as solid-phase extraction materials for selective extraction of trans-resveratrol from giant knotweed extracting solution successfully.

  6. Synthesis, characterization and evaluation of uniformly sized core-shell imprinted microspheres for the separation trans-resveratrol from giant knotweed

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhaohui, E-mail: zhaohuizhang77@hotmail.com [College of Chemistry and Chemical Engineering, Jishou University, Jishou, 416000 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, 410082 (China); Liu Li; Li Hui [College of Chemistry and Chemical Engineering, Jishou University, Jishou, 416000 (China); Yao Shouzhuo [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, 410082 (China)

    2009-09-15

    A novel core-shell molecularly imprinting microspheres (MIMs) with trans-resveratrol as the template molecule; acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, was prepared based on SiO{sub 2} microspheres with surface imprinting technique. These core-shell trans-resveratrol imprinted microspheres were characterized by infrared spectra (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and high performance liquid chromatography (HPLC). The results showed that these core-shell imprinted microspheres, which take on perfect spherical shape with average shell thickness of 150 nm, exhibit especially selective recognition for trans-resveratrol. These imprinted microspheres were applied as solid-phase extraction materials for selective extraction of trans-resveratrol from giant knotweed extracting solution successfully.

  7. Preparation of nano-hydroxyapatite/poly(l-lactide) biocomposite microspheres

    International Nuclear Information System (INIS)

    Qiu Xueyu; Han Yadong; Zhuang Xiuli; Chen Xuesi; Li Yuesheng; Jing Xiabin

    2007-01-01

    Nano-hydroxyapatite (HA)/poly(l-lactide) (PLLA) composite microspheres with relatively uniform size distribution were prepared by a solid-in-oil-in-water (s/o/w) emusion solvent evaporation method. The encapsulation of the HA nanopaticles in microshperes was significantly improved by grafting PLLA on the surface of the HA nanoparticles (p-HA) during emulsion process. This procedure gave a possibility to obtain p-HA/PLLA composite microspheres with uniform morphology and the encapsulated p-HA nanoparticle loading reached up to 40 wt% (33 wt% of pure HA) in the p-HA/PLLA composite microspheres. The microstructure of composite microspheres from core-shell to single phase changed with the variation of p-HA to PLLA ratios. p-HA/PLLA composite microspheres with the diameter range of 2-3 μm were obtained. The entrapment efficiency of p-HA in microspheres could high up to 90 wt% and that of HA was only 13 wt%. Surface and bulk characterizations of the composite microspheres were performed by measurements such as wide angle X-ray diffraction (WAXD), thermal gravimetric analysis (TGA), environmental scanning electron microscope (ESEM) and transmission electron microscopy (TEM)

  8. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Methods: Cellulose microspheres – formulated with hydroxylpropyl methylcellulose (HPMC) and ethyl cellulose (EC) – and Eudragit microspheres – formulated with Eudragit® S 100 (ES) and Eudragit® RL (ERL) - were prepared by an emulsion-solvent evaporation method. The floating microspheres were evaluated for flow ...

  9. Preparing microspheres of actinide nitrides from carbon containing oxide sols

    International Nuclear Information System (INIS)

    Triggiani, L.V.

    1975-01-01

    A process is given for preparing uranium nitride, uranium oxynitride, and uranium carboxynitride microspheres and the microspheres as compositions of matter. The microspheres are prepared from carbide sols by reduction and nitriding steps. (Official Gazette)

  10. Progress in Preparation of Monodisperse Polymer Microspheres

    Science.gov (United States)

    Zhang, Hongyan

    2017-12-01

    The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

  11. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    ... and characterize indomethacin (IM) microspheres prepared with sugar cane wax microsperes. Methods: Microspheres were prepared by melt-emulsified dispersion and cooling-induced solidification method. The microspheres were characterized by scanning electron microscopy (SEM) and differntial scanning calorimetry ...

  12. Preparation and properties of polyvinyl alcohol microspheres

    International Nuclear Information System (INIS)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

    1986-06-01

    Polyvinyl alcohol (PVA) microspheres, having a size range of ∼150- to 250-μm diameter with 1- to 5-μm wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report

  13. Preparation of polystyrene microsphere with emulsion microencapsulation method

    International Nuclear Information System (INIS)

    Li Bo Zhang Lin; Zhang Zhganwen; You Dan; Wei Yun; Wang Chaoyang; Lin Bo; Shi Tao; Chu Qiaomei

    2003-01-01

    The preparation of hollow polystyrene microspheres that are used as inner shell of multi-shell plastic microspheres in the ICF experiments is focused on. The effects of surfactants, water-soluble polymer and electrolyte on the properties of resultant microspheres are studied. Based on these experiments, a fabricating procedure was established with which hollow microspheres were prepared with diameter about 150-3000 μm, wall thickness 0.8-15 μm and toughness Ra less than 4 nm. (authors)

  14. Preparation of porous zirconia microspheres by internal gelation method

    International Nuclear Information System (INIS)

    Pathak, Sachin S.; Pius, I.C.; Bhanushali, R.D.; Rao, T.V. Vittal; Mukerjee, S.K.

    2008-01-01

    A modified internal gelation process for the preparation of porous zirconia microspheres has been developed. The conventional method has been modified by adding a surfactant in the feed broth. The effects of variation of surfactant concentration, washing techniques and temperature of calcination on the pore volume and the surface area of the microspheres have been studied. The conditions were optimized to obtain porous stable microspheres suitable for various applications. The microspheres were characterized by surface area analysis, pore volume analysis, thermogravimetric analysis and X-ray diffraction. The ion exchange behavior was studied using pH titration

  15. Preparation and Characterization of Fluorescent SiO2 Microspheres

    Science.gov (United States)

    Xu, Cui; Zhang, Hao; Guan, Ruifang

    2018-01-01

    Fluorescent compound without typical fluorophores was synthesized with citric acid (CA) and aminopropyltriethoxysilane (APTS) firstly, and then it was grafted to the surface of the prepared SiO2 microspheres by chemical reaction. The fluorescent SiO2 microspheres with good fluorescent properties were obtained by optimizing the reaction conditions. And the morphology and structure of the fluorescent SiO2 microspheres have been characterized by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. The results showed that the preparation of fluorescent SiO2 microspheres have good monodispersity and narrow particle size distribution. Moreover, the fluorescent SiO2 microspheres can be applied to detect Fe3+ in aqueous solution, prepare fluorescent SiO2 rubber, and have potential to be applied in the fluorescent labeling and fingerprint appearing technique fields.

  16. Preparation of mesoporous zirconia microspheres as inert matrix

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Ting [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Wang, Chen; Lv, Jinlong [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Liang, Tongxiang, E-mail: txliang@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2016-12-01

    Mesoporous zirconia microspheres, with a diameter of 900 μm, were prepared as an inert accelerator driven system (ADS) transmutation element matrix by the sol-gel method. The purpose of mesopores is to improve the adsorption capacity of inert matrix fuel (IMF) for minor actinides. The study indicated that the mesoporous zirconia performance was improved after the microspheres were hydrothermally treated at 150 °C, the specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g, and hydrothermal treatment avoided the cracking of the microspheres. Pre-decomposition of the organics during the hydrothermal process stabilized the mesoporous structure. The average pore diameter of mesoporous microsphere was 14.3 nm. - Highlights: • Mesoporous zirconia microspheres with a diameter of 900 μm were prepared as ADS transmutation element inert matrix. • The mesoporous performance was improved after the microspheres were hydrothermally treated at 150 °C. • The specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g. • The hydrothermal treatment could avoid the cracking of the microspheres. • The specific surface area of mesoporous microsphere was 61.28 m{sup 2}/g and the average pore diameter was 14.3 nm.

  17. Preparation and In-vitro Evaluation of Metformin Microspheres Using ...

    African Journals Online (AJOL)

    . Methods: Metformin microspheres were prepared by non-aqueous solvent evaporation method using various polymers, including ethylcellulose (EC), hydroxypropyl methylcellulose (HPMC), carbopol 934P (CA) and chitosan (CH). The effect ...

  18. Preparation of a reproducible long-acting formulation of risperidone-loaded PLGA microspheres using microfluidic method.

    Science.gov (United States)

    Jafarifar, Elham; Hajialyani, Marziyeh; Akbari, Mona; Rahimi, Masoud; Shokoohinia, Yalda; Fattahi, Ali

    2017-09-01

    The aim of the present study is to prepare risperidone-loaded poly lactic-co-glycolic acid (PLGA) microspheres within microfluidic system and to achieve a formulation with uniform size and monotonic and reproducible release profile. In comparison to batch method, T-junction and serpentine chips were utilized and optimizing study was carried out at different processing parameters (e.g. PLGA and surfactant concentration and flow rates ratio of outer to inner phase). The computational fluid dynamic (CFD) modeling was performed, and loading and release study were carried out. CFD simulation indicates that increasing the flow rate of aqueous phase cause to decrease the droplet size, while the change in size of microspheres did not follow a specific pattern in the experimental results. The most uniform microspheres and narrowest standard deviation (66.79 μm ± 3.32) were achieved using T-junction chip, 1% polyvinylalcohol, 1% PLGA and flow rates ratio of 20. The microfluidic-assisted microspheres were more uniform with narrower size distribution. The release of risperidone from microspheres produced by the microfluidic method was more reproducible and closer to zero-order kinetic model. The release profile of formulation with 2:1 drug-to-polymer ratio was the most favorable release, in which 41.85% release could be achieved during 24 days.

  19. Preparation of UN microspheres by internal gelation process

    Energy Technology Data Exchange (ETDEWEB)

    Shirasu, Yoshiro; Yamagishi, Shigeru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    UN microspheres were prepared from (UO{sub 3}+C) microspheres internally gelled in a hot silicone oil column. The gel microspheres were calcined at 480degC in nitrogen, after washing and drying. The calcined ones were carbothermically nitrided at 1400-1800degC in a nitrogen-based atmosphere in two ways: one in N{sub 2} followed by N{sub 2}-8%H{sub 2}, and the other in N{sub 2}-8%H{sub 2} only. In both cases, highly pure UN microspheres around 500 ppm of both oxygen and carbon impurities were obtained, although their densities were still low. (author)

  20. Preparation and Characterization of Colon-Specific Microspheres of ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate colon specific drug delivery system of diclofenac sodium for highly localized delivery to the colon. Methods: The colon specific drug delivery system was prepared as matrix-type microspheres using Ethyl Cellulose (EC), Cellulose Acetate Phthalate (CAP), and Eudragit L 100-55 by the ...

  1. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Erah

    simulated gastric fluid for at least 12 h, and, therefore, could potentially ... systems (GRFDDS) have a bulk density ... The objective of this work was to develop and characterise gastroretentive floating microspheres of silymarin which, following oral administration, would exhibit .... hydrochloric acid to maintain sink conditions.

  2. Facile Preparation of Phosphotungstic Acid-Impregnated Yeast Hybrid Microspheres and Their Photocatalytic Performance for Decolorization of Azo Dye

    Directory of Open Access Journals (Sweden)

    Lan Chen

    2013-01-01

    Full Text Available Phosphotungstic acid (HPW-impregnated yeast hybrid microspheres were prepared by impregnation-adsorption technique through tuning pH of the aqueous yeast suspensions. The obtained products were characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermogravimetry-differential scanning calorimetry (TG-DSC, and ultraviolet-visible spectrophotometry (UV-Vis, respectively. FE-SEM and EDS ascertain that the HPW has been effectively introduced onto the surface of yeast, and the resulting samples retain ellipsoid shape, with the uniform size (length 4.5 ± 0.2 μm, width 3.0 ± 0.3 μm and good monodispersion. XRD pattern indicates that the main crystal structure of as-synthesized HPW@yeast microsphere is Keggin structure. TG-DTA states that the HPW in composites has better thermal stability than pure HPW. Fourier transform infrared spectroscopy (FT-IR elucidates that the functional groups or chemical bonds inherited from the pristine yeast cell were critical to the assembling of the composites. UV-Vis shows that the obtained samples have a good responding to UV light. The settling ability indicates that the hybrid microspheres possess an excellent suspension performance. In the test of catalytic activity, the HPW@yeast microsphere exhibits a high photocatalytic activity for the decoloration of Methylene blue and Congo red dye aqueous solutions, and there are a few activity losses after four cycles of uses.

  3. Preparation of alumina microspheres. Its application as in inorganic exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Santos, W.R. dos; Abrao, A [Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo (Brazil). Centro de Engenharia Quimica

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina microspheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO/sub 2/, ThO/sub 2/). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper.

  4. Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

    Science.gov (United States)

    Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

    2013-12-01

    electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials. Electronic supplementary information (ESI) available: SEM images of microspheres prepared from electrospraying PMMA solution without nonsolvent. See DOI: 10.1039/c3nr05281h

  5. Preparation and characterization of microspheres of albumin-heparin conjugates

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Cremers, H.F.M.; Feijen, Jan

    1991-01-01

    Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form

  6. Preparation of open porous polycaprolactone microspheres and their applications as effective cell carriers in hydrogel system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qingchun [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Ke; Ye, Zhaoyang [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Zhang, Yan, E-mail: zhang_yan@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Wensong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China)

    2012-12-01

    Common hydrogel, composed of synthetic polymers or natural polysaccharides could not support the adhesion of anchorage-dependent cells due to the lack of cell affinitive interface and high cell constraint. The use of porous polyester microspheres as cell-carriers and introduction of cell-loaded microspheres into the hydrogel system might overcome the problem. However, the preparation of the open porous microsphere especially using polycaprolactone (PCL) has been rarely reported. Here, the open porous PCL microspheres were fabricated via the combined emulsion/solvent evaporation and particle leaching method. The microspheres exhibited porous surface and inter-connective pore structure. Additionally, the pore structure could be easily controlled by adjusting the processing parameters. The surface pore size could be altered from 20 {mu}m to 80 {mu}m and the internal porosities were varied from 30% to 70%. The obtained microspheres were evaluated to delivery mesenchymal stem cells (MSCs) and showed the improved cell adhesion and growth when compared with the non-porous microspheres. Then, the MSCs loaded microspheres were introduced into agarose hydrogel. MSCs remained alive and sustained proliferation in microsphere/agarose composite in 5-day incubation while a decrement of MSCs viabilities was found in agarose hydrogel without microspheres. The results indicated that the microsphere/hydrogel composite had a great potential in cell therapy and injectable system for tissue regeneration. Highlights: Black-Right-Pointing-Pointer The open porous polycaprolactone microspheres were fabricated using paraffin as a porogen. Black-Right-Pointing-Pointer The microspheres exhibited porous surface and inter-connective pore structure. Black-Right-Pointing-Pointer The surface and internal pore size and porosity of microsphere could be controlled. Black-Right-Pointing-Pointer The porous microspheres exhibited an improved cell adhesion and proliferation. Black

  7. Preparation of polymer microspheres by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Naka, Y.; Yamamoto, Y.; Yoshida, Y.; Tagawa, S.

    1995-01-01

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  8. Preparation and drug controlled release of porous octyl-dextran microspheres.

    Science.gov (United States)

    Hou, Xin; Liu, Yanfei

    2015-01-01

    In this work, porous octyl-dextran microspheres with excellent properties were prepared by two steps. Firstly, dextran microspheres were synthesized by reversed-phase suspension polymerization. Secondly, octyl-dextran microspheres were prepared by the reaction between dextran microspheres and ethylhexyl glycidyl ether and freezing-drying method. Porous structure of microspheres was formed through the interaction between octyl groups and organic solvents. The structure, morphology, dry density, porosity and equilibrium water content of porous octyl-dextran microspheres were systematically investigated. The octyl content affected the properties of microspheres. The results showed that the dry density of microspheres decreased from 2.35 to 1.21 g/ml, porosity increased from 80.68 to 95.05% with the octyl content increasing from 0.49 to 2.28 mmol/g. Meanwhile, the equilibrium water content presented a peak value (90.18%) when the octyl content was 2.25 mmol/g. Octyl-dextran microspheres showed high capacity. Naturally drug carriers play an important role in drug-delivery systems for their biodegradability, wide raw materials sources and nontoxicity. Doxorubicin (DOX) was used as a drug model to examine the drug-loading capacity of porous octyl-dextran microspheres. The drug-loading efficiency increased with the increase in microspheres/drug ratio, while the encapsulation efficiency decreased. When microspheres/drug mass ratio was 4/1, the drug-loading efficiency and encapsulation efficiency were 10.20 and 51.00%, respectively. The release rate of DOX increased as drug content and porosity increased. In conclusion, porous octyl-dextran microspheres were synthesized successfully and have the potential to serve as an effective delivery system in drug controlled release.

  9. Preparation of magnetic nanoparticles embedded in polystyrene microspheres

    International Nuclear Information System (INIS)

    Nguyen Hoang Hai; Nguyen Hoang Luong; Nguyen Chau; Ngo Quy Tai

    2009-01-01

    Superparamagnetic particles are widely used for biological applications such as cell separation. The size of the particles is normally in the range of 10 - 20 nm which is much smaller than the size of a cell. Therefore small particles create small force which is not strong enough to separate the cells from solution. Superparamagnetic nanoparticles embedded in Polystyrene microspheres (magnetic beads) are very useful for cell separation. Magnetic beads have been prepared by solvent evaporation of an emulsion. The beads with size of 0.2 μm - 1.0 μm have a saturation magnetization of 10 - 25 emu/g. The change of the amount of surfactants, volatile solvent, magnetic particles resulted to the change of size, magnetic properties of the magnetic beads.

  10. Supercritical fluid extraction of silicone oil from uranate microspheres prepared by sol-gel process

    International Nuclear Information System (INIS)

    Kumar, R.; Venkatakrishnan, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2005-01-01

    Supercritical fluid extraction of silicone oil from urania microspheres prepared through sol-gel route was investigated. The influence of pressure, temperature, and flow rate on the extraction efficiency was studied. Experimental conditions were optimised for the complete removal of silicone oil from urania microspheres. (author)

  11. 188Re-microspheres of albumin - the potential preparation for radiotherapy

    International Nuclear Information System (INIS)

    Dyomin, D.N.; Petriev, V.M.

    2000-01-01

    In this paper author describe preparation the albumin microspheres labelled with rhenium-188. We undertake an attempt to develop kits to the generator of rhenium-188 on the basis of albumin microspheres for radiotherapy of both oncological and non-oncological diseases. Microspheres, rhenium-188 with sizes 1 0-20 micron for treatment of rheumatoid arthritis (damage of large and intermediate joints), intraperitoneal administration and intrapleural administration at metastases covering a cavity. Microspheres, Re-188 with sizes 40-60 micron for treatment of disseminated kidney cancer (intraarterial, selectively), intratumoral administration to damaged nodules less than 2-3 cm. Microspheres, Re-188 with sizes 80-100 micron for large neoplasms and metastases of liver (intraarterial, selectively), intratumoral administration to damaged nodules with sizes over 3 cm. Preparation of albumin microspheres is carried out by thermal denaturation of protein in vegetable oil. Microspheres are obtained with the necessary range of sizes by ultrasonic fractionation. At our laboratory the method of preparation of albumin microspheres with any sizes of particles (from 5 -10 up to 800 -1000 microns) has been developed. (authors)

  12. Carboxyl-Functionalized Polymeric Microspheres Prepared by One-Stage Photoinitiated RAFT Dispersion Polymerization

    Directory of Open Access Journals (Sweden)

    Jianbo Tan

    2017-12-01

    Full Text Available Herein, we report a photoinitiated reversible addition-fragmentation chain transfer (RAFT dispersion copolymerization of methyl methacrylate (MMA and methyl methacrylic (MAA for the preparation of highly monodisperse carboxyl-functionalized polymeric microspheres. High rates of polymerization were observed, with more than 90% particle yields being achieved within 3 h of UV irradiation. Effects of reaction parameters (e.g., MAA concentration, RAFT agent concentration, photoinitiator concentration, and solvent composition were studied in detail, and highly monodisperse polymeric microspheres were obtained in most cases. Finally, silver (Ag composite microspheres were prepared by in situ reduction of AgNO3 using the carboxyl-functionalized polymeric microspheres as the template. The obtained Ag composite microspheres were able to catalyze the reduction of methylene blue (MB with NaBH4 as a reductant.

  13. Preparation of berbamine loaded chitosan-agarose microspheres and in vitro release study

    Directory of Open Access Journals (Sweden)

    Zhang Hu

    2012-01-01

    Full Text Available Berbamine loaded chitosan-agarose microspheres were prepared using a water-in-oil emulsion technique. Optimum preparing parameters were determined by orthogonal experiments as follows: ratio of berbamine to chitosan (w/w is 1:10; percentage of emulsifier (span 80, v/v is 6%; volume of glutaraldehyde is 2 mL; and reaction temperature is 70 ºC. Under these optimal conditions, the encapsulation efficiency and loading capacity of microspheres are 84.57% and 8.44%, respectively. The swelling tests showed that the microspheres possessed higher swelling ratio at pH 7.4 than at pH 1.2. FTIR indicated that berbamine had been successfully loaded in the chitosan-agarose microspheres by physical entrapment. In vitro release studies showed that berbamine was released from microspheres in a significantly sustained fashion.

  14. Preparation and characterization of composite microspheres for brachytherapy and hyperthermia treatment of cancer

    International Nuclear Information System (INIS)

    Zhao Di; Huang Wenhai; Rahaman, Mohamed N.; Day, Delbert E.; Wang Deping; Gu Yifei

    2012-01-01

    Composite microspheres were prepared by coating yttrium–aluminum–silicate (YAS) glass microspheres (20–30 μm) with a layer of Fe 3 O 4 nanoparticles and evaluated for potential use in brachytherapy and hyperthermia treatment of cancer. After neutron activation to form the β-emitting 90 Y radionuclide, the composite microspheres can be injected into a patient to destroy cancerous tumors; at the same time, the composite microspheres can generate heat upon application of a magnetic field to also destroy the tumors. The results showed that the composite microspheres were chemically durable when immersed in a simulated body fluid (SBF), with ∼ 0.25% weight loss and ∼ 3.2% yttrium dissolved into the SBF after 30 days at 37 °C. The composite microspheres also showed ferromagnetic properties as a result of the Fe 3 O 4 coating; when immersed in water at 20 °C (20 mg in 1 mL of water), the application of an alternating magnetic field produced a temperature increase from 20 °C to 38−46 °C depending on the thickness of the Fe 3 O 4 coating. The results indicate that these composite microspheres have promising potential in combined brachytherapy and hyperthermia treatment of cancerous tumors. - Highlights: ► Composite microspheres for brachytherapy and hyperthermia treatment of cancer. ► Fe 3 O 4 nanoparticles coated on the yttrium–aluminum–silicate glass microspheres. ► Microspheres are chemically stable in SBF. ► Microspheres can generate heat for hyperthermia under an alternating magnetic field. ► Microspheres can emit β-rays for brachytherapy after neutron activation.

  15. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Li Fengxia [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Xiaoli, E-mail: lixiaoli0903@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Bin, E-mail: libinzh62@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China)

    2011-11-15

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 {mu}m. Magnetic Fe{sub 3}O{sub 4} was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: > We prepare magnetic polylactic acid microspheres loading curcumin. > The classical oil-in-water emulsion solvent-evaporation method is used. > The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 {mu}m. > They show a certain sustained release effect on in vitro drug releasing.

  16. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    International Nuclear Information System (INIS)

    Li Fengxia; Li Xiaoli; Li Bin

    2011-01-01

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 μm. Magnetic Fe 3 O 4 was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: → We prepare magnetic polylactic acid microspheres loading curcumin. → The classical oil-in-water emulsion solvent-evaporation method is used. → The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 μm. → They show a certain sustained release effect on in vitro drug releasing.

  17. Photocatalytic activities of heterostructured TiO2-graphene porous microspheres prepared by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    Yang, Jikai; Zhang, Xintong; Li, Bing; Liu, Hong; Sun, Panpan; Wang, Changhua; Wang, Lingling; Liu, Yichun

    2014-01-01

    Highlights: • USP method is used to prepare TiO 2 -graphene porous microspheres. • XPS shows GO sheets in the composites has been reduced to graphene. • TiO 2 -graphene microspheres display a red-shifted absorption edge. • PL spectra indicate graphene can accept the photoexcited electrons from TiO 2 . • TiO 2 -graphene shows higher photocatalytic activity than TiO 2 under solar light. -- Abstract: TiO 2 -graphene porous microspheres were prepared by ultrasonic spray pyrolysis (USP) of aqueous suspension of graphene oxide containing TiO 2 nanoparticles (Degussa P25). The composite microspheres were characterized with SEM, XPS, photoluminescence, Raman and UV–Vis absorption spectra. TiO 2 -graphene porous microspheres displayed higher photocatalytic activity for the degradation of methylene blue solution than pristine TiO 2 microspheres under the irradiation of Xe lamp, and the highest activity was obtained at a weight percentage of graphene around 1%. The effect of graphene on photocatalytic activity of porous microsphere was discussed in terms of the enhanced charge separation by TiO 2 -graphene heterojunction, increased absorption of the visible light, as well as the possible hindrance of mass transportation in microspheres

  18. Preparation and properties of hollow glass microspheres for use in laser fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.

    1983-11-01

    We review the preparation of high quality, hollow-glass microspheres for use in laser driven fusion experiments at LLNL. The primary focus of this paper is on the liquid-droplet method for making glass spheres, which has been in use at LLNL for over six years. We have combined the results from previous studies with our current results to present a detailed description of the preparation and the composition and physical properties of the glass microspheres. We also present a mathematical model that simulates the microsphere formation process. Examples are given of the application of the model to study the effects of various process parameters.

  19. Preparation and properties of hollow glass microspheres for use in laser fusion experiments

    International Nuclear Information System (INIS)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.

    1983-01-01

    We review the preparation of high quality, hollow-glass microspheres for use in laser driven fusion experiments at LLNL. The primary focus of this paper is on the liquid-droplet method for making glass spheres, which has been in use at LLNL for over six years. We have combined the results from previous studies with our current results to present a detailed description of the preparation and the composition and physical properties of the glass microspheres. We also present a mathematical model that simulates the microsphere formation process. Examples are given of the application of the model to study the effects of various process parameters

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

    DEFF Research Database (Denmark)

    Guo, Wenjia; Quan, Peng; Fang, Liang

    2015-01-01

    -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...... 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...

  1. Adipose-Derived Stem Cell Delivery into Collagen Gels Using Chitosan Microspheres

    Science.gov (United States)

    2010-02-17

    Porous CSM of uniform size and composition were prepared and used as a stem cell carrier. ASC were allowed to attach to the microspheres and infiltrate...and viable, could be retrieved from the spheres, and maintained expression of stem - cell -specific markers. Electron microscopic evaluation of the cell

  2. Sustained release of simvastatin from hollow carbonated hydroxyapatite microspheres prepared by aspartic acid and sodium dodecyl sulfate.

    Science.gov (United States)

    Wang, Ke; Wang, Yinjing; Zhao, Xu; Li, Yi; Yang, Tao; Zhang, Xue; Wu, Xiaoguang

    2017-06-01

    Hollow carbonated hydroxyapatite (HCHAp) microspheres as simvastatin (SV) sustained-release vehicles were fabricated through a novel and simple one-step biomimetic strategy. Firstly, hollow CaCO 3 microspheres were precipitated through the reaction of CaCl 2 with Na 2 CO 3 in the presence of aspartic acid and sodium dodecyl sulfate. Then, the as-prepared hollow CaCO 3 microspheres were transformed into HCHAp microspheres with a controlled anion-exchange method. The HCHAp microspheres were 3-5μm with a shell thickness of 0.5-1μm and were constructed of short needle nanoparticles. The HCHAp microspheres were then loaded with SV, exhibiting excellent drug-loading capacity and sustained release properties. These results present a new material synthesis strategy for HCHAp microspheres and suggest that the as-prepared HCHAp microspheres are promising for applications in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Preparation and Comparative Bioavailability Studies of Indomethacin-Loaded Cetyl Alcohol Microspheres

    Directory of Open Access Journals (Sweden)

    N. Vishal Gupta

    2013-01-01

    Full Text Available The purpose of the present study was to compare the in vitro release and to find out whether the bioavailability of a 75 mg indomethacin capsule (Microcid SR was equivalent to optimized formulation (indomethacin-loaded cetyl alcohol microspheres. Indomethacin-loaded cetyl alcohol microspheres were prepared by meltable emulsified cooling-induced technique. Surface morphology of microspheres has been evaluated using scanning electron microscopy. A single dose, randomized, complete cross over study of IM microspheres was carried out on 10 healthy male and female Albino sheep’s under fasting conditions. The plasma was separated and the concentrations of the drug were determined by HPLC-UV method. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The SEM images revealed the spherical shape of fat microspheres, and more than 98.0% of the isolated microspheres were in the size range 12–32 μm. DSC, FTIR spectroscopy and stability studies indicated that the drug after encapsulation with fat microspheres was stable and compatible. Both formulations were found to be bioequivalent as evidenced by in vivo studies. Based on this study, it can be concluded that cetyl alcohol microspheres and Microcid SR capsule are bioequivalent in terms of the rate and extent of absorption.

  4. Microspheres for protein delivery prepared from amphiphilic multiblock copolymers. 1. Influence of preparation techniques on particle characteristics and protein delivery.

    Science.gov (United States)

    Bezemer, J M; Radersma, R; Grijpma, D W; Dijkstra, P J; van Blitterswijk, C A; Feijen, J

    2000-07-03

    The entrapment of lysozyme in amphiphilic multiblock copolymer microspheres by emulsification and subsequent solvent removal processes was studied. The copolymers are composed of hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(butylene terephthalate) (PBT) blocks. Direct solvent extraction from a water-in-oil (w/o) emulsion in ethanol or methanol did not result in the formation of microspheres, due to massive polymer precipitation caused by rapid solvent extraction in these non-solvents. In a second process, microspheres were first prepared by a water-in-oil-in-water (w/o/w) emulsion system with 4% poly(vinyl alcohol) (PVA) as stabilizer in the external phase, followed by extraction of the remaining solvent. As non-solvents ethanol, methanol and mixtures of methanol and water were employed. However, the use of alcohols in the extraction medium resulted in microspheres which gave an incomplete lysozyme release at a non-constant rate. Complete lysozyme release was obtained from microspheres prepared by an emulsification-solvent evaporation method in PBS containing poly(vinyl pyrrolidone) (PVP) or PVA as stabilizer. PVA was most effective in stabilizing the w/o/w emulsion. Perfectly spherical microspheres were produced, with high protein entrapment efficiencies. These microspheres released lysozyme at an almost constant rate for approximately 28 days. The reproducibility of the w/o/w emulsion process was demonstrated by comparing particle characteristics and release profiles of three batches, prepared under similar conditions.

  5. Preparation and antibacterial property of silver decorated carbon microspheres

    International Nuclear Information System (INIS)

    Li, Sha; Yan, Xiaoliang; Yang, Zhi; Yang, Yongzhen; Liu, Xuguang; Zou, Jing

    2014-01-01

    Carbon microspheres (CMSs) were prepared by glucose hydrothermal method. The effects of glucose concentration and reaction time on the size and morphology of CMSs were studied. CMSs with surface area of 642.5 m 2 /g and pore size of 0.8 nm were exploited to design hybrid material of CMSs with Ag decoration by radio frequency plasma (RF plasma). A series of investigations using X-ray diffraction, UV–vis spectrometry, Fourier transform infrared spectrometry, X-ray photoelectron spectrometry, thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy was carried out to characterize the Ag decorated CMSs. RF plasma was employed to reduce Ag + ions to metallic nano-particles with the particle size of 10–20 nm and form a clean metal-support (Ag-CMSs) interface. The mechanism for the structure formation of Ag decorated CMSs was discussed. Plasma produced Ag/CMSs showed antibacterial property and proved suitable for potential biological and environmental applications.

  6. Preparation of Polysaccharide-Based Microspheres by a Water-in-Oil Emulsion Solvent Diffusion Method for Drug Carriers

    Directory of Open Access Journals (Sweden)

    Yodthong Baimark

    2013-01-01

    Full Text Available Polysaccharide-based microspheres of chitosan, starch, and alginate were prepared by the water-in-oil emulsion solvent diffusion method for use as drug carriers. Blue dextran was used as a water-soluble biomacromolecular drug model. Scanning electron microscopy showed sizes of the resultant microspheres that were approximately 100 μm or less. They were spherical in shape with a rough surface and good dispersibility. Microsphere matrices were shown as a sponge. Drug loading efficiencies of all the microspheres were higher than 80%, which suggested that this method has potential to prepare polysaccharide-based microspheres containing a biomacromolecular drug model for drug delivery applications.

  7. A novel approach to preparing magnetic protein microspheres with core-shell structure

    International Nuclear Information System (INIS)

    Jiang Wei; Sun Zhendong; Li Fengsheng; Chen Kai; Liu Tianyu; Liu Jialing; Zhou Tianle; Guo Rui

    2011-01-01

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3 O 4 cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe 3 O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail. - Research Highlights: → Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method.→ The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3 O 4 cores and coated with globular bovine serum albumin (BSA).→ 57.8 wt% of approximately 10 nm superparamagnetic Fe 3 O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides the abundant functional groups.

  8. A novel approach to preparing magnetic protein microspheres with core-shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Wei, E-mail: climentjw@126.co [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Sun Zhendong; Li Fengsheng [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen Kai; Liu Tianyu; Liu Jialing [Department of Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Zhou Tianle [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Guo Rui [Department of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2011-03-15

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe{sub 3}O{sub 4} cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe{sub 3}O{sub 4} nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail. - Research Highlights: Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe{sub 3}O{sub 4} cores and coated with globular bovine serum albumin (BSA). 57.8 wt% of approximately 10 nm superparamagnetic Fe{sub 3}O{sub 4} nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides the abundant functional groups.

  9. Polydimethylsiloxane microspheres with poly(methyl methacrylate) coating: Modelling, preparation, and characterization

    OpenAIRE

    Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren; Skov, Anne Ladegaard

    2015-01-01

    Polydimethylsiloxane (PDMS) microspheres are prepared by mixing homogeneous dispersions of vinyl-functional PDMS and a curing agent using mechanical stirring in a series of aqueous solutions, and curing at 80 8C for 2 h. In order to verify the experimental diameter and size distributions of the PDMS microspheres, the Hinze-Kolmogorov theory is applied to predict the mean diameter, and a population balance model as well as the maximum entropy formalism are used to describe the size distributio...

  10. Preparation and characterization of alginate microspheres for sustained protein delivery within tissue scaffolds

    International Nuclear Information System (INIS)

    Zhai Peng; Chen, X B; Schreyer, David J

    2013-01-01

    Tissue engineering scaffolds are designed not only to provide structural support for the repair of damaged tissue, but can also serve the function of bioactive protein delivery. Here we present a study on the preparation and characterization of protein-loaded microspheres, either alone or incorporated into mock tissue scaffolds, for sustained protein delivery. Alginate microspheres were prepared by a novel, small-scale water-in-oil emulsion technique and loaded with fluorescently labeled immunoglobulin G (IgG). Microsphere size appears to be influenced by the magnitude and distribution of force generated by mechanical stirring during emulsion. Protein release studies show that sustained IgG release from microspheres could be achieved and that application of a secondary coating of chitosan could further slow the rate of protein release. Preservation of bioactivity of released IgG protein was confirmed using an immunohistochemical assay. When IgG-loaded microspheres were incorporated into mock scaffolds, initial protein release was diminished and the overall time course of release was extended. The present study demonstrates that protein-loaded microspheres can be prepared with a controlled release profile and preserved biological activity, and can be incorporated into scaffolds to achieve sustained and prolonged protein delivery in a tissue engineering application. (paper)

  11. Preparation of hollow hydroxyapatite microspheres by the conversion of borate glass at near room temperature

    International Nuclear Information System (INIS)

    Yao, Aihua; Ai, Fanrong; Liu, Xin; Wang, Deping; Huang, Wenhai; Xu, Wei

    2010-01-01

    Hollow hydroxyapatite microspheres, consisting of a hollow core and a porous shell, were prepared by converting Li 2 O-CaO-B 2 O 3 glass microspheres in dilute phosphate solution at 37 o C. The results confirmed that Li 2 O-CaO-B 2 O 3 glass was transformed to hydroxyapatite without changing the external shape and dimension of the original glass object. Scanning electron microscopy images showed the shell wall of the microsphere was built from hydroxyapatite particles, and these particles spontaneously align with one another to form a porous sphere with an interior cavity. Increase in phosphate concentration resulted in an increase in the reaction rate, which in turn had an effect on shell wall structure of the hollow hydroxyapatite microsphere. For the Li 2 O-CaO-B 2 O 3 glass microspheres reacted in low-concentration K 2 HPO 4 solution, lower reaction rate and a multilayered microstructure were observed. On the other hand, the glass microspheres reacted in higher phosphate solution converted more rapidly and produced a single hydroxyapatite layer. Furthermore, the mechanism of forming hydroxyapatite hollow microsphere was described.

  12. Microwave Irradiation Assisted Preparation of Chitosan Composite Microsphere for Dye Adsorption

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2017-01-01

    Full Text Available Chitosan-activated carbon composite microspheres were prepared by emulsion cross-linking method and its adsorption properties for methyl orange were studied. Chitosan solution was mixed with activated carbon powder and then chitosan was cross-linked by epichlorohydrin under microwave irradiation. SEM photos show that the composite microspheres have diameters of 200–400 μm and activated carbon powder dispersed on the surface of composite microsphere. FTIR spectrum indicates chitosan is successfully cross-linked. Microwave irradiation can effectively shorten the cross-linking time. Composite microspheres have enhanced dye adsorption capacity for methyl orange compared to chitosan microspheres. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Isotherm studies show that the isotherm adsorption equilibrium is better described by Freundlich isotherm. Regeneration results show that adsorption capacity of composite microsphere decreased about 5.51% after being reused for three times. These results indicated that chitosan-activated carbon composite microsphere has potential application in the removal of dye from wastewaters.

  13. A novel approach to preparing magnetic protein microspheres with core-shell structure

    Science.gov (United States)

    Jiang, Wei; Sun, Zhendong; Li, Fengsheng; Chen, Kai; Liu, Tianyu; Liu, Jialing; Zhou, Tianle; Guo, Rui

    2011-03-01

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3O 4 cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe 3O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail.

  14. loaded Eudragit RL 100 Microspheres Prepared by an Emulsion

    African Journals Online (AJOL)

    Erah

    drug release profiles of the microspheres at pH 1.2 showed poor drug release characteristics while at. pH 6.8 ... drug delivery, improve bioavailability and stability and target drug to ... The factors affecting particle size, drug loading and drug.

  15. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    HP

    scanning calorimetry (DSC) as well as for drug loading, and in vitro and in vivo release in albino sheeps. Results: SEM images .... Rolex, India), and the sphericity factor (S) was calculated using ... using a fully validated high performance liquid ... Pharmacokinetic and data analysis ... microspheres exerts an influence on the.

  16. Preparation And Biodistribution Study Of 153sm-Albumin Microspheres As Radiosynovectomy Agent

    International Nuclear Information System (INIS)

    W, Widyatuti; Tamat, Swasono R.; Indrawati, Teti; Fatimah; Aulya, Anna

    2003-01-01

    Treatment of rheumatics arthritis previously was done by inflamed synovial membrane surgery called synovectomy. The conventional synovectomy was costly and inconvenient method for the patients, therefore alternative method using radiation synovectomy was considered. Preparation of 153 Sm albumin microspheres as radio synovectomy agent has been candied out. Experiments have been carried out to decide optimal conditions of preparation, such as speed and time of stirring to form microspheres, and to find optimal condition in labelling the microspheres, such as pH, content of sodium citrate, samarium oxide and the amount of microspheres. The albumin particles were expected as spheres with 15-50 μm in diameter, high labelling efficiency and 153 Sm is strongly bound to the microspheres. In-vitro and in-vivo stability were tested by observing 153 Sm released from the particles after incubating the labelled particles in saline and human serum albumin solution for one week, and after administration of labelled particles into Wistar rats via intraarticular injection through one of its knee joint. The result shows the optimal speed and time of stirring to obtain desired shape and size of the particles was 750 rpm in 15 minutes, while the optimal formulation to obtain high labelling efficiency was at pH 5-6, containing 10 μg/mL of sodium citrate, 125 μg/mL of samarium oxide and 10 mg of albumin microspheres. The preparation was stable up to 5 days. In conclusion the 153 Sm-albumin microspheres can be produced and is ready for clinical trial

  17. Preparation and evaluation of enrofloxacin microspheres and tissue distribution in rats.

    Science.gov (United States)

    Yang, Fan; Kang, Jijun; Yang, Fang; Zhao, Zhensheng; Kong, Tao; Zeng, Zhenling

    2015-01-01

    New enrofloxacin microspheres were formulated, and their physical properties, lung-targeting ability, and tissue distribution in rats were examined. The microspheres had a regular and round shape. The mean diameter was 10.06 µm, and the diameter of 89.93% of all microspheres ranged from 7.0 µm to 30.0 µm. Tissue distribution of the microspheres was evaluated along with a conventional enrofloxacin preparation after a single intravenous injection (7.5 mg of enrofloxacin/kg bw). The results showed that the elimination half-life (t1/2β) of enrofloxacin from lung was prolonged from 7.94 h for the conventional enrofloxacin to 13.28 h for the microspheres. Area under the lung concentration versus time curve from 0 h to ∞ (AUC00∞) was increased from 11.66 h·µg/g to 508.00 h·µg/g. The peak concentration (Cmax) in lung was increased from 5.95 µg/g to 93.36 µg/g. Three lung-targeting parameters were further assessed and showed that the microspheres had remarkable lung-targeting capabilities.

  18. Preparation and photocatalytic activity of hollow ZnSe microspheres via Ostwald ripening

    International Nuclear Information System (INIS)

    Zhang Lihui; Yang Heqing; Xie Xiaoli; Zhang Fenghua; Li Li

    2009-01-01

    Hollow ZnSe microspheres were prepared via a facile hydrothermal reaction of Zn(AC) 2 .2H 2 O with Na 2 SeO 3 and ethylene glycol in NaOH solution at 180 deg. C for 12 h. The products were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectrum. The hollow microspheres with the diameters of about 2 μm are constructed from ZnSe nanoparticles with the cubic zinc blende structure, the size of hollow interiors and constituent ZnSe nanodots can be tuned by changing the reaction time. The hollow microspheres are formed via an Ostwald ripening process. Photoluminescence and photocatalytic activity of the hollow ZnSe microspheres were studied at room temperature. The results indicate that the hollow microspheres constructed from ZnSe nanoparticles display a strong near-band edge emission at 479 nm and a very weak deep defect (DD) related emission at 556 nm and a high photocatalytic activity in the photodegradation of methyl orange. The photodegradation of methyl orange catalyzed by the ZnSe microspheres is a pseudo first-order reaction

  19. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Preparation and in vitro/in vivo characterization of curcumin microspheres intended to treat colon cancer

    Directory of Open Access Journals (Sweden)

    M Madhavi

    2012-01-01

    Full Text Available Objective: The objective of the present investigation was to prepare colon targeted curcumin microspheres using Eudragit S100 and evaluate the same for in vitro/in vivo properties. Materials and Methods: A "O/O solvent evaporation" technique was used in the preparation of microspheres. The influence of various process variables including stirring speed, drug:polymer ratio and percentage of emulsifier on the fabrication were investigated and the formulation was optimized. Prepared microspheres were evaluated for in vitro and in vivo properties. Surface morphology, particle size, percentage drug entrapment, percentage yield, drug polymer interaction, in vitro drug release in simulated gastrointestinal transit conditions and stability were the in vitro parameters investigated. Using an optimized formulation, drug release into the systemic circulation and organ distribution were investigated as in vivo parameters. In vivo parameters were estimated in male albino rats. Results: Curcumin microspheres of Eudragit S100 were successfully prepared using o/o solvent evaporation method. Microspheres prepared using 1:2 drug:polymer ratio, with a stirring speed of 1000 rpm, and using 1.0% w/v concentration of emulsifying agent was selected as an optimized formulation. The release studies with optimized formulation demonstrated that aqueous solubility of curcumin was enhanced by 8 times with the formulation. FTIR studies demonstrated no change in drug characteristics upon microsphere fabrication. The enhancement in solubility is thus due to the increase in the surface area of the drug substance and not due to a change of drug to a different physical state. This was further confirmed by scanning electron microsphere pictures. Drug release followed Korsmeyer and Peppas release model. Accelerated stability studies indicated that the drug is stable in the formulation for a period of atleast 14 weeks at room temperature. In vivo studies demonstrated a sustained

  1. Chitosan magnetic microspheres for technological applications: Preparation and characterization

    International Nuclear Information System (INIS)

    Podzus, P.E.; Daraio, M.E.; Jacobo, S.E.

    2009-01-01

    One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 μm. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

  2. PREPARATION AND CHARACTERIZATION OF POROUS WALLED HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F; Erich Hansen, E; Ray Schumacher, R; David Peeler, D

    2008-04-21

    Porous-walled hollow glass microspheres (PWHGMs) of a modified alkali borosilicate composition have been successfully fabricated by combining the technology of producing hollow glass microspheres (HGMs) with the knowledge associated with porous glasses. HGMs are first formed by a powder glass--flame process, which are then transformed to PWHGMs by heat treatment and subsequent treatment in acid. Pore diameter and pore volume are most influenced by heat treatment temperature. Pore diameter is increased by a factor of 10 when samples are heat treated prior to acid leaching; 100 {angstrom} in non-heat treated samples to 1000 {angstrom} in samples heat treated at 600 C for 8 hours. As heat treatment time is increased from 8 hours to 24 hours there is a slight shift increase in pore diameter and little or no change in pore volume.

  3. 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.

  4. Preparation and Characterization of SiO2/SiCN Core-shell Ceramic Microspheres

    Directory of Open Access Journals (Sweden)

    ZHANG Hai-yuan

    2017-05-01

    Full Text Available The SiO2/PSN core-shell microspheres were prepared via an emulsion reaction combined with the polymer-derived ceramics (PDCs method using polysilazane (PSN in situ polymerization on the surface of SiO2 modified by silane coupling agents MPS, followed by pyrolysis process to obtain SiO2/SiCN core-shell ceramic microspheres. The effects of raw mass ratio, curing time and pyrolysis temperature on the formation and the morphology of core-shell microspheres were studied. The morphology, chemical composition and phase transformation were characterized by SEM, EDS, TEM, FT-IR and XRD. The results show that after reaction for 4h at 200℃, SiO2 completely coated PSN forms a core-shell microsphere with rough surface when the mass ratio of SiO2 and PSN is 1:4; when pyrolysis temperature is at 800-1200℃, amorphous SiO2/SiCN core-shell ceramic microspheres are prepared; at 1400℃, the amorphous phase partially crystallizes to produce SiO2, SiC and Si3N4 phase.

  5. Preparation of Syndiotactic Poly(vinyl alcohol)/Poly(vinyl pivalate/vinyl acetate) Microspheres with Radiopacity Using Suspension Copolymerization and Saponification

    Science.gov (United States)

    Seok Lyoo, Won; Wook Cha, Jin; Young Kwak, Kun; Jae Lee, Young; Yong Jeon, Han; Sik Chung, Yong; Kyun Noh, Seok

    2010-06-01

    To prepare Poly(vinyl pivalate/vinyl acetate) [P(VPi/VAc)] microspheres with radiopacity, the suspension copolymerization approach in the presence of aqueous radiopaque nanoparticles was used. After, The P(VPi/VAc) microspheres with radiopacity were saponified in heterogeneous system, and then P(VPi/VAc) microspheres without aggregates were converted to s-PVA/P(VPi/VAc) microspheres of skin/core structure through the heterogeneous surface saponification. Radiopacity of microspheres was confirmed with Computed tomography (CT).

  6. Preparation of a Microspherical Silver-Reduced Graphene Oxide-Bismuth Vanadate Composite and Evaluation of Its Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Mao Du

    2016-03-01

    Full Text Available A novel Ag-reduced graphene oxide (rGO-bismuth vanadate (BiVO4 (AgGB ternary composite was successfully synthesized via a one-step method. The prepared composite was characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, Brunauer-Emmett-Teller (BET surface area measurement, Raman scattering spectroscopy, and ultraviolet-visible diffuse-reflection spectroscopy (UV-vis DRS. The results showed that bulk monoclinic needle-like BiVO4 and Ag nanoparticles with a diameter of approximately 40 nm formed microspheres (diameter, 5–8 μm with a uniform size distribution that could be loaded on rGO sheets to facilitate the transport of electrons photogenerated in BiVO4, thereby reducing the rate of recombination of photogenerated charge carriers in the coupled AgGB composite system. Ag nanoparticles were dispersed on the surface of the rGO sheets, which exhibited a localized surface plasmon resonance phenomenon and enhanced visible light absorption. The removal efficiency of rhodamine B dye by AgGB (80.2% was much higher than that of pure BiVO4 (51.6% and rGO-BiVO4 (58.3% under visible light irradiation. Recycle experiments showed that the AgGB composite still presented significant photocatalytic activity after five successive cycles. Finally, we propose a possible pathway and mechanism for the photocatalytic degradation of rhodamine B dye using the composite photocatalyst under visible light irradiation.

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

    International Nuclear Information System (INIS)

    Chao, Shao Ching; Wang, Ming-Jia; Pai, Nai-Su; Yen, Shiow-Kang

    2015-01-01

    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 3 ) 2 , NH 4 H 2 PO 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

  8. 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.

  9. Facile preparation of ZIF-8@Pd-CSS sandwich-type microspheres via in situ growth of ZIF-8 shells over Pd-loaded colloidal carbon spheres with aggregation-resistant and leach-proof properties for the Pd nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tong; Lin, Lu [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Zhang, Xiongfu, E-mail: xfzhang@dlut.edu.cn [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Liu, Haiou; Yan, Xinjuan [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Liu, Zhang; Yeung, King Lun [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR (China)

    2015-10-01

    Graphical abstract: - Highlights: • Uniform-sized colloidal carbon spheres were synthesized from low-cost glucose. • Pd nanoparticles were loaded onto the carbon spheres via self-reduction method. • A layer of ZIF-8 shell was in situ grown over the Pd-loaded carbon spheres. • The ZIF-8@Pd-CCS showed leach-proof and aggregation-resistant properties of Pd. - Abstract: Aiming to enhance the stability of noble metal nanoparticles that are anchored on the surface of colloidal carbon spheres (CCSs), we designed and prepared a new kind of sandwich-structured ZIF-8@Pd-CCS microsphere. Typically, uniform CCSs were first synthesized by the aromatization and carbonization of glucose under hydrothermal conditions. Subsequently, noble metal nanoparticles, herein Pd nanoparticles, were attached to the surface of CCSs via self-reduction route, followed by in situ assembly of a thin layer of ZIF-8 over the Pd nanoparticles to form the sandwich-type ZIF-8@Pd-CCS microspheres. X-ray diffraction (XRD) patterns and Fourier transform infrared spectroscopy (FTIR) spectra confirmed the presence of crystalline ZIF-8, while TEM analysis revealed that the ZIF-8 shells were closely bound to the Pd-loaded CCSs. The shell thickness could be tuned by varying the ZIF-8 assembly cycles. Further, liquid-phase hydrogenation of 1-hexene as the probe reaction was carried out over the ZIF-8@Pd-CCS microspheres and results showed that the prepared microspheres exhibited excellent agglomeration-resistant and leach-proof properties for the Pd nanoparticles, thus leading to the good reusability of the ZIF-8@Pd-CCS microspheres.

  10. Microsphere preparation using highly branched dextran degraded by electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Min Ho; Yoo, Sun Kyun [Joongbu Univ., Geumsan (Korea, Republic of); Kang, Hyun Suk; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-07-01

    Dextrans as noble alternative consist predominantly of linear a-1,6 glucose linkages with some degree of branching via 1,2-, 1,3-, or 1,4- linkage. Dextrans have been investigated as potential macromolecular carriers for delivery of drugs and proteins, primarily to increase the longevity of therapeutic agents in the delivery of drugs and proteins, primarily to increase the longevity of therapeutic agents in the circulation. In most previous researches, linear type of dextrans with molecular weight of new type of drug delivery agent. Since 1950, the clinical dextran has been manufactured by acid hydrolysis, of which processes are multi-steps and time-consumed. Therefore, the objective of this research is evaluate the microsphere synthesised by highly branched dextran degraded by a electron beam radiation. Linear type of dextran was purchased from Sigma company. Branch type of dextran was produced and purified in our lab. The branch degree of dextran was evaluated using dextranase and analyzed by TLC. The air-dry dextran and two solution dextran was irradiated at room temperature using a electrostatic beam. The electron beam energy applied was 1.0 to 2.5 MeV. Dose was 70 kGy. The molecular average weight if 11,215,000 of linear dextran and 7,413,000 was degraded to 213,000 and 112,000, respectively. Branched dextran applied by a beam still retained its branched structure. The size of microsphere was dependant of the amount of PPG added to make water to water emulsion. Swelling of microsphere of branched dextran was higher than of linear dextran.

  11. Microsphere preparation using highly branched dextran degraded by electron beam

    International Nuclear Information System (INIS)

    Oh, Min Ho; Yoo, Sun Kyun; Kang, Hyun Suk; Lee, Byung Cheol

    2011-01-01

    Dextrans as noble alternative consist predominantly of linear a-1,6 glucose linkages with some degree of branching via 1,2-, 1,3-, or 1,4- linkage. Dextrans have been investigated as potential macromolecular carriers for delivery of drugs and proteins, primarily to increase the longevity of therapeutic agents in the delivery of drugs and proteins, primarily to increase the longevity of therapeutic agents in the circulation. In most previous researches, linear type of dextrans with molecular weight of new type of drug delivery agent. Since 1950, the clinical dextran has been manufactured by acid hydrolysis, of which processes are multi-steps and time-consumed. Therefore, the objective of this research is evaluate the microsphere synthesised by highly branched dextran degraded by a electron beam radiation. Linear type of dextran was purchased from Sigma company. Branch type of dextran was produced and purified in our lab. The branch degree of dextran was evaluated using dextranase and analyzed by TLC. The air-dry dextran and two solution dextran was irradiated at room temperature using a electrostatic beam. The electron beam energy applied was 1.0 to 2.5 MeV. Dose was 70 kGy. The molecular average weight if 11,215,000 of linear dextran and 7,413,000 was degraded to 213,000 and 112,000, respectively. Branched dextran applied by a beam still retained its branched structure. The size of microsphere was dependant of the amount of PPG added to make water to water emulsion. Swelling of microsphere of branched dextran was higher than of linear dextran

  12. One-step preparation of zeolite silicalite-1 microspheres with adjustable macroporosity

    KAUST Repository

    Hua, Jia

    2009-06-23

    A facile one-step method was developed for the preparation of zeolite silicalite-1 (or ZSM-5) microspheres without the need of pre-synthesizing zeolite nanocrystals. In this method, Pluronic triblock copolymer F127 was added into a homogeneous silicalite-1 synthesis solution. During the hydrothermal synthesis, zeolite nanocrystals (∼ 100 nm) were formed and spontaneously assembled into uniform micrometer-sized (3-5 μm) spheres due to the presence of F127. The obtained microspheres possess significant textual porosity (up to 0.24 cm 3/g), which can be adjusted by simply adding different amounts of styrene in the synthesis. The zeolite microspheres are useful for enzyme immobilization, and the enzyme loading is proportional to the textual porosity. © 2009 American Chemical Society.

  13. Preparation of hydroxypropyl cyclosophoraose/dextran microspheres for the controlled release of ciprofloxacin

    International Nuclear Information System (INIS)

    Lee, Benel; Jeong, Da Ham; Joo, Sang Woo; Choi, Jae Min; Jung, Seung Ho; Cho, Eun Na; Lee, Jae Yung; Park, Se Yeon

    2016-01-01

    Hydroxypropyl cyclosophoraose/dextran (HPCys/dextran) microspheres were prepared using an emulsion polymerization method for use as drug carriers to achieve the controlled release of a poorly water-soluble antibacterial drug, ciprofloxacin (CFX). Cyclosophoraoses are cyclic (1 → 2)-β-d-glucans isolated from the Rhizobium species. Characteristics of HPCys/dextran microspheres were investigated using Fourier transform infrared analysis, solid-state 13C nuclear magnetic resonance spectroscopy, and field emission scanning electron microscopy. The amount of CFX released from these microspheres at pH 7.4 (intestinal phase pH) was about two times higher than that released at pH 1.2 (gastric phase pH). Furthermore, HPCys/dextran microspheres did not show any toxicity in human embryonic kidney cells. We propose that HPCys/dextran microspheres could be used as an effective pH-dependent release system for poorly water-soluble drugs such as CFX

  14. Preparation of hydroxypropyl cyclosophoraose/dextran microspheres for the controlled release of ciprofloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Benel; Jeong, Da Ham; Joo, Sang Woo; Choi, Jae Min; Jung, Seung Ho; Cho, Eun Na [Center for Biotechnology Research in UBITA (CBRU), Konkuk University, Seoul (Korea, Republic of); Lee, Jae Yung [Dept. Biological Science, Mokpo National University, Mokpo (Korea, Republic of); Park, Se Yeon [Dept. Applied Chemistry, Dongduk Women' s University, Seoul (Korea, Republic of)

    2016-12-15

    Hydroxypropyl cyclosophoraose/dextran (HPCys/dextran) microspheres were prepared using an emulsion polymerization method for use as drug carriers to achieve the controlled release of a poorly water-soluble antibacterial drug, ciprofloxacin (CFX). Cyclosophoraoses are cyclic (1 → 2)-β-d-glucans isolated from the Rhizobium species. Characteristics of HPCys/dextran microspheres were investigated using Fourier transform infrared analysis, solid-state 13C nuclear magnetic resonance spectroscopy, and field emission scanning electron microscopy. The amount of CFX released from these microspheres at pH 7.4 (intestinal phase pH) was about two times higher than that released at pH 1.2 (gastric phase pH). Furthermore, HPCys/dextran microspheres did not show any toxicity in human embryonic kidney cells. We propose that HPCys/dextran microspheres could be used as an effective pH-dependent release system for poorly water-soluble drugs such as CFX.

  15. Preparation and Characterization of Zein and Zein-Chitosan Microspheres with Great Prospective of Application in Controlled Drug Release

    Directory of Open Access Journals (Sweden)

    Vinícius Müller

    2011-01-01

    Full Text Available Biomaterials applied as carriers for controlled drug delivery offer many advantages over the conventional systems. Among them, the increase of treatment effectiveness and also a significant reduction of toxicity, due to their biodegradability property, are some special features. In this work, microspheres based on the protein Zein (ZN and ZN associated to the natural polymer Chitosan (CHI were prepared and characterized. The microspheres of ZN and ZN/CHI were characterized by FT-IR spectroscopy and thermal analysis, and the morphology was analyzed by SEM images. The results confirmed the incorporation of CHI within the ZN-based microspheres. The morphological analysis showed that the CHI added increased the microspheres porosity when compared to the ZN microspheres. The chemical and physical characterization and the morphological analysis allow inferring that ZN/CHI microspheres are good candidates to act as a carrier for controlled drug release.

  16. Preparation and in vitro evaluation of xanthan gum facilitated superabsorbent polymeric microspheres.

    Science.gov (United States)

    Bhattacharya, Shiv Sankar; Mazahir, Farhan; Banerjee, Subham; Verma, Anurag; Ghosh, Amitava

    2013-10-15

    Interpenetrating polymer network (IPN) hydrogel microspheres of xanthan gum (XG) based superabsorbent polymer (SAP) and poly(vinyl alcohol) (PVA) were prepared by water-in-oil (w/o) emulsion crosslinking method for sustained release of ciprofloxacin hydrochloride (CIPRO). The microspheres were prepared with various ratios of hydrolyzed SAP to PVA and extent of crosslinking density. The prepared microspheres with loose and rigid surfaces were evidenced by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the IPN formation. Differential scanning calorimetry (DSC) study was performed to understand the dispersion nature of drug after encapsulation. The in vitro drug release study was extensively evaluated depending on the process variables in both acidic and alkaline media. All the formulations exhibited satisfactory physicochemical and in vitro release characteristics. Release data indicated a non-Fickian trend of drug release from the formulations. Based on the results, this study suggest that CIPRO loaded IPN microspheres were suitable for sustained release application. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Preparation and characterization of genipin-cross-linked silk fibroin/chitosan sustained-release microspheres

    Directory of Open Access Journals (Sweden)

    Zeng SG

    2015-05-01

    Full Text Available Shuguang Zeng,1,* Manwen Ye,1,2,* Junqi Qiu,1 Wei Fang,1 Mingdeng Rong,1 Zehong Guo,1 Wenfen Gao11Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, 2Department of Stomatology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workAbstract: We report the effects of distinct concentrations of genipin and silk fibroin (SF:chitosan (CS ratios on the formation of SF–CS composite microspheres. We selected microspheres featuring an SF:CS ratio of 1:1, encapsulated various concentrations of bovine serum albumin (BSA, and then compared their encapsulation efficiency and sustained-release rate with those of pure CS microspheres. We determined that the following five groups of microspheres were highly spherical and featured particle sizes ranging from 70 µm to 147 µm: mass ratio of CS:SF =1:0.5, 0.1 g or 0.5 g genipin; CS:SF =1:1, 0.05 g or 1 g genipin; and CS:SF =1:2, 0.5 g genipin. The microspheres prepared using 1:1 CS:SF ratio and 0.05 g genipin in the presence of 10 mg, 20 mg, and 50 mg of BSA exhibited encapsulation efficiencies of 50.16%±4.32%, 56.58%±3.58%, and 42.19%±7.47%, respectively. Fourier-transform infrared spectroscopy (FTIR results showed that SF and CS were cross-linked and that the α-helices and random coils of SF were converted into β-sheets. BSA did not chemically react with CS or SF. Moreover, thermal gravimetric analysis (TGA results showed that the melting point of BSA did not change, which confirmed the FTIR results, and X-ray diffraction results showed that BSA was entrapped in microspheres in a noncrystalline form, which further verified the TGA and FTIR data. The sustained-release microspheres prepared in the presence of 10 mg, 20 mg, and 50 mg of BSA burst release 30.79%±3.43%, 34.41%±4.46%, and 41.75%±0.96% of the

  18. Preparation and evaluation of microspheres of xyloglucan and its thiolated xyloglucan derivative.

    Science.gov (United States)

    Sonawane, Savita; Bhalekar, Mangesh; Shimpi, Shamkant

    2014-08-01

    Xyloglucan is a natural polymer reported to possess mucoadhesive properties. To enhance the mucoadhesion potential, xyloglucan was thiolated with cysteine. The microspheres of xyloglucan were prepared using a biocompatible crosslinker sodium trimetaphosphate and it was optimized for formulation variables, namely polymer concentration, internal:external phase ratio and stirring speed using a Box-Behnken experimental design. The formulation was also optimized for performance parameters like entrapment, t80 and % mucoadhesion. The microspheres were characterized by Fourier transform infrared spectroscopy, DSC and SEM for the optimum formula and then were reproduced by replacing the xyloglucan with thiomer. The microspheres formed showed entrapment efficiency of about 80%, t80 of about 400min and % mucoadhesion of 60% while same for thiomer were 90%, 500min and 80% respectively. In oral glucose tolerance test protocol the thiomer microspheres showed significant reduction in blood glucose levels. Thus thiolated xyloglucan offers a better polymer for multiparticulate drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Preparation of polymethacrylic acid-grafted HEMA/PVP microspheres and preliminary study on basic protein adsorption.

    Science.gov (United States)

    Gao, Baojiao; Hu, Hongyan; Guo, Jianfeng; Li, Yanbin

    2010-06-01

    The crosslinked copolymeric microspheres (HEMA/NVP) of N-vinylpyrrolidone (NVP) and 2-hydroxyethyl methacrylate (HEMA) were prepared using inverse suspension polymerization method. Subsequently, the reaction of methacryloyl chloride with the hydroxyl groups on the surfaces of HEMA/NVP microspheres was performed, leading to the introduction of polymerisable double bonds onto the surfaces of microspheres HEMA/NVP. Afterward, methacrylic acid was allowed to be graft-polymerized on microspheres HEMA/NVP in the manner of "grafting from", resulting in the grafted microspheres PMAA-HEMA/NVP. The grafted microspheres PMAA-HEMA/NVP were fully characterized with several means. The graft-polymerization of MAA on microspheres HEMA/NVP was studied in detail, and the optimal reaction conditions were determined. Thereafter, the adsorption property of the grafted microspheres PMAA-HEMA/NVP for lysozyme as a basic protein model was preliminarily examined to explore the feasibility of removing deleterious basic protein such as density lipoprotein from blood. The experimental results indicate that the PMAA grafting degree on microspheres HEMA/NVP is limited because an enwinding polymer layer as a kinetic barrier on the surfaces of HEMA/NVP microspheres will be formed during the graft-polymerization, and block the graft-polymerization. In order to enhance PMAA grafting degree, reaction temperature, monomer concentration and the used amount of initiator should be effectively controlled. The experimental results also reveal that the grafted microspheres PMAA-HEMA/NVP possess very strong adsorption ability for lysozyme by right of strong electrostatic interaction. Copyright 2010 Elsevier B.V. All rights reserved.

  20. Preparation of novel biodegradable ropivacaine microspheres and evaluation of their efficacy in sciatic nerve block in mice

    Directory of Open Access Journals (Sweden)

    Ni Q

    2016-08-01

    Full Text Available Qiang Ni, Wurong Chen, Lei Tong, Jue Cao, Chao Ji Department of Anesthesiology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China Abstract: In this study, ropivacaine chitosan-loaded microspheres for subcutaneous administration were developed. The systems were characterized in terms of surface morphology, particle size, encapsulation efficiency, and in vitro release behavior. Results showed that the microspheres had drug loading rate of 7.3% and encapsulation efficiency of 91.2%, and their average diameter was 2.62±0.76 µm. The morphology study revealed that the microspheres are uniform monodispersed spheres and did not form aggregates in aqueous solution. It was clearly observed that the release profile of ropivacaine microspheres exhibited a biphasic pattern: the initial burst release within the first 2 hours and a following slower and sustained release over a long time. In vivo, a greater area under the plasma concentration–time curve from 0 to t (AUC0–t was obtained from the microspheres (4.27-fold, than from the injection group, which indicated that there was a significantly improved systemic exposure to ropivacaine. Pharmacodynamics result showed that preparing ropivacaine as microsphere preparation could not only extend the drug effect time but also decrease the administration dosage. Keywords: ropivacaine, chitosan, microspheres, in vitro release, pharmacodynamics

  1. Preparation and flow cytometry of uniform silica-fluorescent dye microspheres.

    Science.gov (United States)

    Bele, Marjan; Siiman, Olavi; Matijević, Egon

    2002-10-15

    Uniform fluorescent silica-dye microspheres have been prepared by coating preformed monodispersed silica particles with silica layers containing rhodamine 6G or acridine orange. The resulting dispersions exhibit intense fluorescent emission between 500 and 600 nm, over a broad excitation wavelength range of 460 to 550 nm, even with exceedingly small amounts of dyes incorporated into the silica particles (10-30 ppm, expressed as weight of dye relative to weight of dry particles). The fluorescent particles can be prepared in micrometer diameters suitable for analyses using flow cytometry with 488-nm laser excitation.

  2. Process and equipment development for the preparation of UO2 microspheres using trichloroethylene as gelation medium (Paper No. AL-23)

    International Nuclear Information System (INIS)

    Suryanarayana, S.; Kumar, N.; Bamankar, Y.R.; Vaidya, V.N.; Sood, D.D.

    1990-02-01

    Uranium dioxide microspheres have been prepared by internal gelation process, one of the sol-gel routes for fuel fabrication. The process flow sheet for internal gelation has been modified by employing trichloroethylene(TCE) as an alternate gelation medium. Based on the modified flow sheet, a 5Kg/day assembly for the production of UO 2 microspheres has been developed and installed. (author). 1 fig

  3. Preparation and characterization of quercetin-loaded silica microspheres stabilized by combined multiple emulsion and sol-gel processes

    Directory of Open Access Journals (Sweden)

    Kim Young Ho

    2015-01-01

    Full Text Available Despite exhibiting a wide spectrum of cosmeceutical properties, flavonoids and related compounds have some limitations related to their stability and solubility in distilledwater. In this project, we prepared silica microspheres using a novel method that uses polyol-in-oil-in-water (P/O/W emulsion and sol-gel methods as techniques for stabilizing quercetin. A stable microsphere suspension was successfully preparedusing a mixed solvent system comprising a polyol-phase medium for performing the sol-gel processing of tetraethyl orthosilicate (TEOS as an inorganic precursor with outer water phase. The morphology of the microsphere was evaluated using a scanning electron microscope (SEM, which showed a characteristic spherical particle shape with a smooth surface. Furthermore, SEM/EDSanalysis of a representative microsphere demonstrated that the inner structure of the silica microspheres was filled with quercetin. The mean diameter of the microsphere was in the range 20.6-35.0 μm, and the encapsulation efficiency ranged from 17.8% to 27.5%. The free and encapsulated quercetin samples were incubated in separateaqueous solutions at 25 and 42°C for 28 days. The residualcontent of the quercetin encapsulated by silica microspheres was 82% at 42°C. In contrast, that of the free quercetin stored at 42°C decreased to ~24%.

  4. The preparation of UO2 ceramic microspheres with an advanced process (TGU)

    International Nuclear Information System (INIS)

    Xu Zhichang; Tang Yaping; Zhang Fuhong

    1994-04-01

    The UO 2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). An advanced process for preparation of UO 2 ceramic microspheres has been developed at Institute of Nuclear Energy Technology, Tsinghua University. This process known as total gelation process of uranium (TGU), is based on the traditional sol-gel process, external gelation process and internal gelation process of uranium (EGU and IGU), and has been selected as the production process. The result of batch test is described. Accordance with the requirements of quality control (QC) and quality assurance (QA), the stabilization of operating parameters and product quality is tested., The results on batch test have shown that as well as all of the operated parameters are fixed, then the product quality can be stable as well as the product specification can be met. When the colloidal flow rate and the vibration frequency of nozzle are fixed, the kernel's size is also fixed. When the sintering temperature and time are fixed, the product density is also fixed. When the hydrogen atmosphere is used, the O/U ratio is very near to stoichiometry. The performance and structure of UO 2 ceramic microspheres are also given

  5. Gastric transit and pharmacodynamics of a two-millimeter enteric-coated pancreatin microsphere preparation in patients with chronic pancreatitis

    NARCIS (Netherlands)

    Bruno, M. J.; Borm, J. J.; Hoek, F. J.; Delzenne, B.; Hofmann, A. F.; de Goeij, J. J.; van Royen, E. A.; van Leeuwen, D. J.; Tytgat, G. N.

    1998-01-01

    It has been suggested that enteric-coated pancreatin microsphere (ECPM) preparations with sphere sizes larger than 1.7 mm pass through the stomach at a slower rate than a meal and therefore may be less efficacious in restoring pancreatic enzyme activity than preparations with smaller sphere sizes.

  6. Preparation and antioxidant properties of selenium nanoparticles-loaded chitosan microspheres

    Directory of Open Access Journals (Sweden)

    Bai K

    2017-06-01

    Full Text Available Kaikai Bai,1,2 Bihong Hong,1,2 Jianlin He,1,2 Zhuan Hong,1,2 Ran Tan1,2 1Third Institute of Oceanography, 2Engineering Research Center of Marine Biological Resource, Comprehensive Utilization, State Oceanic Administration, Xiamen, People’s Republic of China Abstract: Selenium nanoparticles (SeNPs, as a special form of selenium (Se supplement, have attracted worldwide attention due to their favorable properties and unique bioactivities. Herein, an eco-friendly and economic way to prepare stable SeNPs is introduced. SeNPs were synthesized in aqueous chitosan (CTS and then embedded into CTS microspheres by spray-drying, forming selenium nanoparticles-loaded chitosan microspheres (SeNPs-M. The physicochemical properties including morphology, elemental state, size distribution and surface potential were investigated. Institute of Cancer Research mice were used as model animal to evaluate the bioactivities of SeNPs-M. Trigonal-phase SeNPs of ~35 nm were synthesized, and SeNPs-M physically embedding those SeNPs were successfully prepared. Amazingly, acute toxicity test indicated that SeNPs-M were much safer than selenite in terms of Se dose, with a LD50 of around 18-fold of that of selenite. In addition, SeNPs-M possessed powerful antioxidant activities, as evidenced by a dramatic increase of both Se retention and the levels of glutathione peroxidase, superoxide dismutase and catalase. The design of SeNPs-M can offer a new way for further development of SeNPs with a higher efficacy and better biosafety. Thus, SeNPs-M may be a potential candidate for further evaluation as an Se supplement with antioxidant properties and be used against Se deficiency in animals and human beings. Keywords: selenium, nano, microsphere, chitosan, antioxidant

  7. Combining Pickering Emulsion Polymerization with Molecular Imprinting to Prepare Polymer Microspheres for Selective Solid-Phase Extraction of Malachite Green

    Directory of Open Access Journals (Sweden)

    Weixin Liang

    2017-08-01

    Full Text Available Malachite green (MG is currently posing a carcinogenic threat to the safety of human lives; therefore, it is highly desirable to develop an effective method for fast trace detection of MG. Herein, for the first time, this paper presents a systematic study on polymer microspheres, being prepared by combined Pickering emulsion polymerization and molecular imprinting, to detect and purify MG. The microspheres, molecularly imprinted with MG, show enhanced adsorption selectivity to MG, despite a somewhat lowered adsorption capacity, as compared to the counterpart without molecular imprinting. Structural features and adsorption performance of these microspheres are elucidated by different characterizations and kinetic and thermodynamic analyses. The surface of the molecularly imprinted polymer microspheres (M-PMs exhibits regular pores of uniform pore size distribution, endowing M-PMs with impressive adsorption selectivity to MG. In contrast, the microspheres without molecular imprinting show a larger average particle diameter and an uneven porous surface (with roughness and a large pore size, causing a lower adsorption selectivity to MG despite a higher adsorption capacity. Various adsorption conditions are investigated, such as pH and initial concentration of the solution with MG, for optimizing the adsorption performance of M-PMs in selectively tackling MG. The adsorption kinetics and thermodynamics are deeply discussed and analyzed, so as to provide a full picture of the adsorption behaviors of the polymer microspheres with and without the molecular imprinting. Significantly, M-PMs show promising solid-phase extraction column applications for recovering MG in a continuous extraction manner.

  8. Formulation, characterization and in vitro evaluation of theophylline-loaded Eudragit RS 100 microspheres prepared by an emulsion-solvent diffusion/evaporation technique.

    Science.gov (United States)

    Jelvehgari, Mitra; Barar, Jaleh; Valizadeh, Hadi; Shadrou, Sanam; Nokhodchi, Ali

    2011-01-01

    The aim was to prepare theophylline-loaded Eudragit RS 100 microsphere to achieve sustained release pattern with relatively high production yield. To this end, microspheres were prepared by oil/oil solvent evaporation method using an acetone-methanol mixture and liquid paraffin system containing aluminum tristearate. Drug release profiles were determined at pH 1.2 and 7.4. Morphology and solid state of microspheres were examined using SEM, DSC, X-ray powder diffraction (XRPD), and FT-IR. As the ratio of acetone/methanol increased during the preparation of microspheres the size of microsphere was reduced. The highest drug loading efficiency (87.21%) was obtained for the microsphere containing a high ratio of polymer to drug (6:1) and high volume of acetone. SEM studies showed that the microspheres are almost spherical with a few pores and cracks at surfaces. The FT-IR, XRPD and DSC results ruled out any chemical interaction between theophylline and Eudragit. The microspheres prepared with low ratio of polymer to drug (1:2) showed faster dissolution rate than those with high polymer to drug ratio. The ratio of polymer to drug and the volume of polymer solvent were found to be the key factors affecting the release profile which could lead to microspheres with desired release behavior.

  9. Optimization of preparation method for ketoprofen-loaded microspheres consisting polymeric blends using simplex lattice mixture design

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sanjoy Kumar, E-mail: sanjoydasju@gmail.com; Khanam, Jasmina; Nanda, Arunabha

    2016-12-01

    In the present investigation, simplex lattice mixture design was applied for formulation development and optimization of a controlled release dosage form of ketoprofen microspheres consisting polymers like ethylcellulose and Eudragit{sup ®}RL 100; when those were formed by oil-in-oil emulsion solvent evaporation method. The investigation was carried out to observe the effects of polymer amount, stirring speed and emulsifier concentration (% w/w) on percentage yield, average particle size, drug entrapment efficiency and in vitro drug release in 8 h from the microspheres. Analysis of variance (ANOVA) was used to estimate the significance of the models. Based on the desirability function approach numerical optimization was carried out. Optimized formulation (KTF-O) showed close match between actual and predicted responses with desirability factor 0.811. No adverse reaction between drug and polymers were observed on the basis of Fourier transform infrared (FTIR) spectroscopy and Differential scanning calorimetric (DSC) analysis. Scanning electron microscopy (SEM) was carried out to show discreteness of microspheres (149.2 ± 1.25 μm) and their surface conditions during pre and post dissolution operations. The drug release pattern from KTF-O was best explained by Korsmeyer-Peppas and Higuchi models. The batch of optimized microspheres were found with maximum entrapment (~ 90%), minimum loss (~ 10%) and prolonged drug release for 8 h (91.25%) which may be considered as favourable criteria of controlled release dosage form. - Graphical abstract: Optimization of preparation method for ketoprofen-loaded microspheres consisting polymeric blends using simplex lattice mixture design. - Highlights: • Simplex lattice design was used to optimize ketoprofen-loaded microspheres. • Polymeric blend (Ethylcellulose and Eudragit® RL 100) was used. • Microspheres were prepared by oil-in-oil emulsion solvent evaporation method. • Optimized formulation depicted favourable

  10. {sup 90}Y microspheres prepared by sol-gel method, promising medical material for radioembolization of liver malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Łada, Wiesława, E-mail: w.lada@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Dorodna 16 (Poland); Iller, Edward [National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Andrzej Sołtan 7 (Poland); Wawszczak, Danuta [Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Dorodna 16 (Poland); Konior, Marcin, E-mail: marcin.konior@polatom.pl [National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Andrzej Sołtan 7 (Poland); Dziel, Tomasz [National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Andrzej Sołtan 7 (Poland)

    2016-10-01

    A new technology for the production of radiopharmaceutical {sup 90}Y microspheres in the form of spherical yttrium oxide grains obtained by sol-gel method has been described. The authors present and discuss the results of investigations performed in the development of new production technology of yttrium microspheres and determination of their physic-chemical properties. The final product has the structure of spherical yttrium oxide grains with a diameter 25–100 μm, is stable and free from contaminants. Irradiation of 20 mg samples of grains with diameter of 20–50 μm in the thermal neutron flux of 1.7 × 10{sup 14} cm{sup −2} s{sup −1} at the core of MARIA research nuclear reactor allowed to obtain microspheres labelled with the {sup 90}Y isotope on the way of the nuclear reaction {sup 89}Y(n, γ){sup 90}Y. Specific activity of irradiated microspheres has been determined by application of absolute triple to double coincidence ratio method (TDCR) and has been evaluated at 190 MBq/mg Y. {sup 90}Y microspheres prepared by the proposed technique can be regarded as a promising medical material for radioembolization of liver malignancies. - Highlights: • Sol-gel methods for preparation of spherical yttrium trioxide grains have been proposed. • Determination condition for irradiation {sup 89}Y{sub 2}O{sub 3} grains in nuclear reactor • Evaluation of specific activity of {sup 90}Y microspheres • Estimation of {sup 90}Y microspheres as promising medical material for radioembolization.

  11. Preparation of crosslinked poly (acryloyloxyethyltrimethyl ammonium chloride) microsphere and its adsorption and mechanism towards shikimic acid

    Energy Technology Data Exchange (ETDEWEB)

    Men, Jiying, E-mail: menjiying@nuc.edu.cn; Wang, Ruixin; Li, Huan; Li, Xinyan; Yang, Shanshan; Liu, Haisi; Gao, Baojiao

    2017-02-01

    Shikimic acid (SA) is a key raw material for the synthesis of the antiviral drug, but its extraction and separation from plants is still limited. Crosslinked poly (acryloyloxyethyltrimethyl ammonium chloride, DAC) microspheres were synthesized via inverse-phase suspension polymerization. In the synthesizing, N,N′-methylene bisacrylamide (MBA) was used as crosslinker, cyclohexane as dispersed medium and span-60 as dispersants, obtaining CPDAC gel microspheres. The effect of polymerization condition on balling performance and the characteristics of CPDAC were examined. The adsorption properties of CPDAC towards SA were mainly explored and the data of adsorption isotherm were analyzed by using Langmuir, Freundlich, Temkin, Sips and Toth models. Furthermore, the adsorption mechanism was analyzed in depth, and the adsorption thermodynamics was also investigated. The results show that in order to prepare CPDAC, water phase must be added dropwise to oil phase, and the volume ratio of oil-water is more than 2:1. The mean diameter of CPDAC decreases with increasing span-60 and accelerating agitating rate. The strong electrostatic interaction is formed between quaternary ammonium nitrogen of CPDAC and −COO{sup –} of SA. The adsorption kinetic data is fitted well with pseudo-first-order model. The adsorption ability is higher in aqueous water than ethanol, reaching 108 mg/g, and Toth model is more suitable for describing the actual adsorption process. The adsorption of CPDAC towards SA is dependent on the pH value of the medium. The adsorption process is exothermic, the adsorption amount decreases with the increase of temperature, and the process is driven by enthalpy. The adsorption amount decreases with the increase of salinity. The reusability of CPDAC towards SA can keep 86.1% at the sixth cycle. - Highlights: • CPDAC microspheres were synthesized via inverse-phase suspension polymerization. • SA was adsorbed strongly by strong electrostatic interaction.

  12. Preparation of Drug-loaded Chitosan Microspheres and Its Application in Paper-based PVC Wallpaper

    Science.gov (United States)

    Lin, Hui; Chen, Lihui; Yan, Guiyang; Chen, Feng; Huang, Liulian

    2018-03-01

    By screening through test, it was found that the drug-loaded chitosan microspheres with the average particle size of 615 nm may be prepared with NaF as the mold-proof drug, chitosan as the drug carrier and sodium tripolyphosphate as the cross-linking agent; and they can improve the aspergillus niger-proof effect if loaded onto the base paper surface of the paper-based PVC wallpaper. The results show that NaF and chitosan have mold-proof synergistic effects; the mold-proof effect of the wallpaper may be improved by increasing the dose of chitosan; when the mass ratio of NaF, sodium tripolyphosphate and chitosan was 2:7:28, the paper-based PVC wallpaper with good mold-proof property can be prepared.

  13. Rambutan-like FeCO3 hollow microspheres: facile preparation and superior lithium storage performances.

    Science.gov (United States)

    Zhong, Yiren; Su, Liwei; Yang, Mei; Wei, Jinping; Zhou, Zhen

    2013-11-13

    Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, ~880 mAh g(-1) after 100 cycles at 50 mA g(-1), and ~710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li(+) diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.

  14. The Calculation of Ho Production by indirect Method and Preparation of Polymeric Microsphere for Radioembolisation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K. H.; Kim, J. B.; Park, U. J.; Cho, E. H.; Nam, S. S.; Yoo, K. M.; Jang, K. D. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The reactor-produced radiolanthanides have been essential for development of therapeutic radiopharmaceuticals because they emit proper beta energies to induce tumor necrosis. Some radiolanthanides are very useful in that they have the ability of simultaneous diagnosis and therapeutic effect. This nuclide with both capacities is called as theranostic nuclide. In general, radiolanthanides can be produced by (n,γ) and (n,γ)β reaction. Of the two reactions, (n,γ)β reaction-product, shows high specific activity which is important things to affect labeling yield, is suitable for preparing the radiophamaceuticals comprising the antibody or peptide. Some radiolanthanides show the good theranostic effect in that they have proper LET (Linear Energy Transfer) to induce apoptosis for cancer and gamma ray to use as a tracer for cancer diagnosis. Although Ho-166 has been studied for therapeutic purpose since early 1990, production has been limited to direct method. To inject Dy/Ho mixture into the microsphere, we first set-up the concepts which are prior metal-administration method and posterior administration method. The latter is shown in this paper. Metal inletting process was done by using alternating between vacuum and pressurization. To prevent the leak of metal ions from metal/microsphere hybrid, surface coating was done by using interfacial reaction between saline and THF contained Poly lactic acid. Surface coating is simply completed just swiveling the vial. All experiments in this study, we just only tested with cold state.

  15. Preparation of grafted microspheres CPVA-g-PSSS and studies on their drug-carrying and colon-specific drug delivery properties

    International Nuclear Information System (INIS)

    Gao, Baojiao; Fang, Li; Men, Jiying; Zhang, Yanyan

    2013-01-01

    Sodium 4-styrene sulfonate (SSS) was graft-polymerized on the surfaces of crosslinked polyvinyl alcohol (CPVA) microspheres in a manner of surface-initiated graft-polymerization by using cerium salt-hydroxyl group redox initiation system, obtaining the grafted microspheres CPVA-g-PSSS. The chemical structure and physicochemical characters of CPVA-g-PSSS microspheres were fully characterized with infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and zeta potential determination. The aim of this work is to constitute a novel colon-specific drug delivery system via molecular design by using CPVA-g-PSSS microspheres as the drug-carrying material and by taking metronidazole (MTZ) as the model drug. The drug-carrying ability and mechanism of the grafted microspheres CPVA-g-PSSS for MTZ were investigated. Finally, in-vitro release tests for the drug-carrying microspheres were conducted. The experimental results show that in an acidic medium, the grafted microspheres CPVA-g-PSSS exhibit strong adsorption ability for MTZ by driving of electrostatic interaction, and have an adsorption capacity of 112 mg/g, displaying the high efficiency of drug-carrying. The in-vitro release behavior of the drug-carried microspheres is highly pH-sensitive. In the medium of pH = 1, the drug-carrying microspheres do not release the drug, whereas in the medium of pH = 7.4, a sudden delivery phenomenon of the drug will occur, displaying an excellent colon-specific drug delivery behavior. Highlights: ► A metronidazole colon-specific drug delivery was constituted using grafted polymeric microspheres. ► Grafted polymeric microspheres CPVA-g-PSSS were prepared via surface-initiated graft-polymerization. ► The release of the drug-carrying microspheres is highly pH-sensitive. ► The drug-carrying microspheres display an excellent colon-specific drug delivery behavior

  16. Preparation of grafted microspheres CPVA-g-PSSS and studies on their drug-carrying and colon-specific drug delivery properties

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Baojiao, E-mail: gaobaojiao@126.com [Department of Chemical Engineering, North University of China, Taiyuan 030051, People' s Republic of China (China); Fang, Li [School of Chemistry and Chemical engineering, Shanxi University, Taiyuan 030006 (China); Men, Jiying; Zhang, Yanyan [Department of Chemical Engineering, North University of China, Taiyuan 030051, People' s Republic of China (China)

    2013-04-01

    Sodium 4-styrene sulfonate (SSS) was graft-polymerized on the surfaces of crosslinked polyvinyl alcohol (CPVA) microspheres in a manner of surface-initiated graft-polymerization by using cerium salt-hydroxyl group redox initiation system, obtaining the grafted microspheres CPVA-g-PSSS. The chemical structure and physicochemical characters of CPVA-g-PSSS microspheres were fully characterized with infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and zeta potential determination. The aim of this work is to constitute a novel colon-specific drug delivery system via molecular design by using CPVA-g-PSSS microspheres as the drug-carrying material and by taking metronidazole (MTZ) as the model drug. The drug-carrying ability and mechanism of the grafted microspheres CPVA-g-PSSS for MTZ were investigated. Finally, in-vitro release tests for the drug-carrying microspheres were conducted. The experimental results show that in an acidic medium, the grafted microspheres CPVA-g-PSSS exhibit strong adsorption ability for MTZ by driving of electrostatic interaction, and have an adsorption capacity of 112 mg/g, displaying the high efficiency of drug-carrying. The in-vitro release behavior of the drug-carried microspheres is highly pH-sensitive. In the medium of pH = 1, the drug-carrying microspheres do not release the drug, whereas in the medium of pH = 7.4, a sudden delivery phenomenon of the drug will occur, displaying an excellent colon-specific drug delivery behavior. Highlights: ► A metronidazole colon-specific drug delivery was constituted using grafted polymeric microspheres. ► Grafted polymeric microspheres CPVA-g-PSSS were prepared via surface-initiated graft-polymerization. ► The release of the drug-carrying microspheres is highly pH-sensitive. ► The drug-carrying microspheres display an excellent colon-specific drug delivery behavior.

  17. Determination of Ideal Broth Formulations Needed to Prepare Hydrous Cerium Oxide Microspheres via the Internal Gelation Process

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Jack Lee [ORNL; Chi, Anthony [ORNL

    2009-02-01

    A simple test tube methodology was used to determine optimum process parameters for preparing hydrous cerium oxide microspheres via the internal gelation process.1 Broth formulations of cerium ammonium nitrate [(NH4)2Ce(NO3)6], hexamethylenetetramine, and urea were found that can be used to prepare hydrous cerium oxide gel spheres in the temperature range of 60 to 90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations to be able to equate the test-tube gelation times to actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broth formulations.

  18. Polydimethylsiloxane microspheres with poly(methyl methacrylate) coating: Modelling, preparation, and characterization

    DEFF Research Database (Denmark)

    Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren

    2015-01-01

    functional PDMS microspheres were coated with poly(methyl methacrylate) (PMMA) by spin coating with different concentrations of PMMA solutions. The quality of the resulting PMMA shell is investigated using rheological measurements at 50 8C with a timesweep procedure. The results strongly suggest that PMMA-coated...... PDMS microspheres react around 20 times slower than the uncoated ones, and that the PMMA shell significantly hinders the reaction between the PDMS microsphere and cross-linker. Thus the thin PMMA shells are very efficient in protecting the reactive PDMS microspheres, since the PMMA shell forms...

  19. Preparation of chitosan/nano hydroxyapatite organic-inorganic hybrid microspheres for bone repair.

    Science.gov (United States)

    Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Zhong, Shengnan; Zhang, Qiqing

    2015-10-01

    In this work, we encapsulated icariin (ICA) into chitosan (CS)/nano hydroxyapatite (nHAP) composite microspheres to form organic-inorganic hybrid microspheres for drug delivery carrier. The composition and morphology of composite microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry- thermogravimetric analysis (DSC-TGA). Moreover, we further studied the performance of swelling properties, degradation properties and drug release behavior of the microspheres. ICA, the extract of traditional Chinese medicine-epimedium, was combined to study drug release properties of the microspheres. ICA loaded microspheres take on a sustained release behavior, which can be not only ascribed to electrostatic interaction between reactive negative hydroxyl (OH) of ICA and positive amine groups (NH₂) of CS, but also depended on the homogeneous dispersion of HAP nanoparticles inside CS organic matrix. In addition, the adhesion and morphology of osteoblasts were detected by inverted fluorescence microscopy. The biocompatibility of CS/nHAP/ICA microspheres was evaluated by the MTT cytotoxicity assay, Hoechst 33258 and PI fluorescence staining. These studies demonstrate that composite microspheres provide a suitable microenvironment for osteoblast attachment and proliferation. It can be speculated that the ICA loaded CS-based organic-inorganic hybrid microspheres might have potential applications in drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Preparation and CO{sub 2} adsorption properties of aminopropyl-functionalized mesoporous silica microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Araki, S.; Doi, H.; Sano, Y.; Tanaka, S.; Miyake, Y. [Hitachi Zosen Corp., Osaka (Japan). Technical Research Institute

    2009-11-15

    Aminopropyl-functionalized mesoporous silica microspheres (AF-MSM) were synthesized by a simple one-step modified Stober method. Dodecylamine (DDA) was used as the catalyst for the hydrolysis and condensation of the silica source and as the molecular template to prepare the ordered mesopores. The mesoporous silica surfaces were modified to aminopropyl groups by the co-condensation of tetraethoxysilane (TEOS) with 3-aminopropyltriethoxysilane (APTES), up to a maximum of 20 mol.% APTES content in the silica source. The particle size, Brunauer-Emmet-Teller (BET) specific surface area, and mesoporous regularity decreased with increasing APTES content. It is believed that this result is caused by a decreasing amount of DDA incorporated into AF-MSM with increasing APTES content. It was also confirmed that the spherical shape and the mesostructure were maintained even if 20 mol.% of APTES was added to the silica source. Moreover, AF-MSM was applied to the CO{sub 2} adsorbent. The breakthrough time of the CO{sub 2} and CO{sub 2} adsorption capacities increased with increasing APTES content. The adsorption capacity of CO{sub 2} for AF-MSM, prepared at 20 mol.% APTES, was 0.54 mmol g{sup -1}. Carbon dioxide adsorbed onto AF-MSM was completely desorbed by heating in a N{sub 2} purge at 423 K for 30 min.

  1. [Preparation of citrulline microspheres by spray drying technique for colonic targeting].

    Science.gov (United States)

    Bahri, S; Zerrouk, N; Lassoued, M-A; Tsapis, N; Chaumeil, J-C; Sfar, S

    2014-03-01

    Citrulline is an amino acid that becomes essential in situations of intestinal insufficiency such as short bowel syndrome. It is therefore interesting to provide the patients with dosage forms for routing citrulline to the colon. The aim of this work is to formulate microspheres of citrulline for colonic targeting by the technique of spray drying. Eudragit(®) FS 30D was selected as polymer to encapsulate citrulline using the spray drying technique. Citrulline and Eudragit(®) FS 30D were dissolved in water and ethanol, respectively. The aqueous and the ethanolic solutions were then mixed in 1:2 (v/v) ratio. Microspheres were obtained by nebulizing the citrulline-Eudragit(®) FS 30D solution using a Mini spray dryer equipped with a 0.7mm nozzle. The microspheres have been formulated using citrulline and Eudragit(®) FS 30D. The size distribution of microspheres was determined by light diffraction. The morphology of the microspheres was studied by electron microscopy. Manufacturing yields, encapsulation rate and dissolution profiles were also studied. The microspheres obtained had a spherical shape with a smooth surface and a homogeneous size except for the microspheres containing the highest concentration of polymer (90 %). The formulation showed that the size and morphology of the microspheres are influenced by the polymer concentration. Manufacturing yields were about 51 % but encapsulation rate were always very high (above 90 %). The in vitro dissolution study showed that the use of the Eudragit(®) FS 30D under these conditions is not appropriate to change the dissolution profile of the citrulline. This technique has led to the formulation of microspheres with good physical properties in terms of morphology and size. The compression of the microspheres should help to control citrulline release for colonic targeting. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  2. Microencapsulation by solvent extraction/evaporation: reviewing the state of the art of microsphere preparation process technology.

    Science.gov (United States)

    Freitas, Sergio; Merkle, Hans P; Gander, Bruno

    2005-02-02

    The therapeutic benefit of microencapsulated drugs and vaccines brought forth the need to prepare such particles in larger quantities and in sufficient quality suitable for clinical trials and commercialisation. Very commonly, microencapsulation processes are based on the principle of so-called "solvent extraction/evaporation". While initial lab-scale experiments are frequently performed in simple beaker/stirrer setups, clinical trials and market introduction require more sophisticated technologies, allowing for economic, robust, well-controllable and aseptic production of microspheres. To this aim, various technologies have been examined for microsphere preparation, among them are static mixing, extrusion through needles, membranes and microfabricated microchannel devices, dripping using electrostatic forces and ultrasonic jet excitation. This article reviews the current state of the art in solvent extraction/evaporation-based microencapsulation technologies. Its focus is on process-related aspects, as described in the scientific and patent literature. Our findings will be outlined according to the four major substeps of microsphere preparation by solvent extraction/evaporation, namely, (i) incorporation of the bioactive compound, (ii) formation of the microdroplets, (iii) solvent removal and (iv) harvesting and drying the particles. Both, well-established and more advanced technologies will be reviewed.

  3. Preparation and Comparative Characterization of Alginate-Made Microcapsules and Microspheres Containing Tomato, Seabuckthorn Juices and Pumpkin Oil

    Directory of Open Access Journals (Sweden)

    Florina Csernatoni

    2015-05-01

    Full Text Available Recent studies have shown the benefits of tomatoes, seabuckthorn juices and pumpkin oil, rich in bioactives with antioxidant capacity, in the prevention of prostate diseases. To stabilize their antioxidant activity, microencapsulation represent a good technological alternative, improving the stability and bioavailability of bioactive molecules ( phenolic derivatives, carotenoids, phytosterols, vitamins.   The aim of the study was to prepare and characterize microspheres and microcapsules based on emulsions made of natural polymers like Natrium alginate mixed with tomato and/or seabuckthorn juices, with or without pumpkin oil.  The viscosity of emulsions, the morphology of microcapsules and microspheres were characterized comparatively and the bioactives were monitored by UV-Vis spectrometry.  In the lipophilic extract there were identified, before and after encapsulation, different classes of compounds, from lipids, to phenolic acid derivatives, flavonoids and carotenoids. Carotenoids were the major components having concentrations from 9.16 up to 19.71 mg/100 g sample. The viscosity of  each emulsion including juices, oil and natrium alginate 2%, before encapsulation, showed differences, dependent on the oil addition and speed of homogenization. The macroscopic and microscopic structure of microspheres and microcapsules were comparatively evaluated. Both microspheres and microcapsules had external diameters  ranging from 750 to 900 μm and the microcapsules’ oily core of 150-180 μm. The results obtained from emulsion’s viscosity will be correlated with the rigidity and optimal release rate of bioactive molecules from microcapsules and microspheres.  Further studies are directed towards these aspects.

  4. 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 (P GMA-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 P GMA-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

  5. 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.

  6. Microsphere formation in droplets using antisolvent vapour precipitation technique

    OpenAIRE

    Chew, Sean Jun Liang

    2017-01-01

    In previous studies, the antisolvent vapour precipitation method has been proven to produce uniformly sized lactose microspheres (1.0 µm) from a single droplet (1.2 mm diameter) at atmospheric pressure. These types of particles have potential applications in the pharmaceutical industry, especially due to their high dissolution rate. This project looked into the possibility of using antisolvent vapour precipitation to produce microspheres from finely atomised droplets. Microspheres in the sub-...

  7. Microspheres for protein delivery prepared from amphiphilic multiblock copolymers. 1. influence of preparation techniques on particle characteristics and protein delivery

    NARCIS (Netherlands)

    Bezemer, J.M.; Radersma, R.; Grijpma, Dirk W.; Dijkstra, Pieter J.; van Blitterswijk, Clemens; Feijen, Jan

    2000-01-01

    The entrapment of lysozyme in amphiphilic multiblock copolymer microspheres by emulsification and subsequent solvent removal processes was studied. The copolymers are composed of hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(butylene terephthalate) (PBT) blocks. Direct solvent

  8. Preparation and physicochemical characteristics of polylactide microspheres of emamectin benzoate by modified solvent evaporation/extraction method.

    Science.gov (United States)

    Zhang, Shao Fei; Chen, Peng Hao; Zhang, Fei; Yang, Yan Fang; Liu, De Kun; Wu, Gang

    2013-12-18

    Emamectin benzoate is highly effective against insect pests and widely used in the world. However, its biological activity is limited because of high resistance of target insects and rapid degradation speed in fields. Preparation and physicochemical characterization of degradable microcapsules of emamectin benzoate were studied by modified solvent evaporation/extraction method using polylactide (PLA) as wall material. The influence of different compositions of the solvent in internal organic phase and external aqueous phase on diameter, span, pesticide loading, and entrapment rate of the microspheres was investigated. The results indicated that the process of solvent extraction and the formation of the microcapsules would be accelerated by adding water-miscible organic solvents such as ethyl ether, acetone, ethyl acetate, or n-butanol into internal organic phase and external aqueous phase. Accelerated formation of the microcapsules would result in entrapment rates of emamectin benzoate increased to as high as 97%. In addition, by adding ethanol into the external aqueous phase, diameters would reduce to 6.28 μm, whereas the loading efficiency of emamectin benzoate did not increase. The PLA microspheres prepared under optimum conditions were smoother and more spherical. The degradation rate in PLA microspheres of emamectin benzoate on the 10th day was 4.29 ± 0.74%, whereas the degradation rates of emamectin benzoate in methanol solution and solid technical material were 46.3 ± 2.11 and 22.7 ± 1.51%, respectively. The PLA skeleton had combined with emamectin benzoate in an amorphous or molecular state by using differential scanning calorimetry (DSC) determination. The results indicated that PLA microspheres of emamectin benzoate with high entrapment rate, loading efficiency, and physicochemical characteristics could be obtained by adding water-miscible organic solvents into the internal organic phase and external aqueous phase.

  9. Preparation of microspheres for slow release drug by radiation-induced suspension polymerization and their properties

    International Nuclear Information System (INIS)

    Yoshida, Masaru; Asano, Masaharu; Kaetsu, Isao

    1982-01-01

    The polymer microspheres containing drugs as drug delivery system were made by means of suspension-polymerization by radiation at low temperature by using glass-forming monomers which have stable supercooling properties and large polymerizability at low temperature. The particle distribution depended on the kind of monomer. It was found that the entrapping yield of drug in polymer microspheres increased with increasing viscosity of monomer and that the maximum value on the particle size distribution curve was also shifted to large particle diameter side. In the case of trimethylolpropane trimethacrylate monomer (43 cps), TMPT, the entrapping yield of drug reached 74% and the maximum value in particle size distribution curve appeared in the neighborhood of 105 to 210 mu m ranges. On the other hand, those values in neopentyl glycol dimethacrylate monomer (4 cps) were 12% in former and 44 -- 105 mu m in the latter. The release phenomenon of drugs from polymer microspheres was investigated. for example, the cumulative amount of mitomycin C (water soluble drug) released from TMPT polymer microsphere was about 90% after 30-day dissolution, while in the case of water-insoluble drug such as testosterone the amount of release was about 49% after 40-day dissolution. In all cases, the release rate is constant during the experimental period. Therefore, it was concluded that the release of drugs from polymer microspheres obtained in this study is possible over the long periods. (author)

  10. Preparation of three-dimensional macroporous chitosan-gelatin B microspheres and HepG2-cell culture.

    Science.gov (United States)

    Huang, Fang; Cui, Long; Peng, Cheng-Hong; Wu, Xu-Bo; Han, Bao-San; Dong, Ya-Dong

    2016-12-01

    Chitosan-gelatin B microspheres with an open, interconnected, highly macroporous (100-200 µm) structure were prepared via a three-step protocol combining freeze-drying with an electrostatic and ionic cross-linking method. Saturated tripolyphosphate ethanol solution (85% ethanol) was chosen as the crosslinking agent to prevent destruction of the porous structure and to improve the biostability of the chitosan-gelatin B microspheres, with N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide/N-hydroxysuccinimide as a second crosslinking agent to react with gelatin A and fixed chitosan-gelatin B microspheres to attain improved biocompatibility. Water absorption of the three-dimensional macroporous chitosan-gelatin B microspheres (3D-P-CGMs) was 12.84, with a porosity of 85.45%. In vitro lysozyme degradation after 1, 3, 5, 7, 10, 14, and 21 days showed improved biodegradation in the 3D-P-CGMs. The morphology of human hepatoma cell lines (HepG2 cells) cultured on the 3D-P-CGMs was spherical, unlike that of cells cultured under traditional two-dimensional conditions. Scanning electron microscopy and paraffin sections were used to confirm the porous structure of the 3D-P-CGMs. HepG2 cells were able to migrate inside through the pore. Cell proliferation and levels of albumin and lactate dehydrogenase suggested that the 3D-P-CGMs could provide a larger specific surface area and an appropriate microenvironment for cell growth and survival. Hence, the 3D-P-CGMs are eminently suitable as macroporous scaffolds for cell cultures in tissue engineering and cell carrier studies. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  11. Structural and morphological studies on poly(3-hydroxybutyrate acid) (PHB)/chitosan drug releasing microspheres prepared by both single and double emulsion processes

    Energy Technology Data Exchange (ETDEWEB)

    Shih, W.-J. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Chen, Y.-H. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-kung Road, Kaohsiung 80782, Taiwan (China); Shih, C.-J. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, No. 100, Shih-Chuang 1st Rd., Sanmin District, Kaohsiung 80708, Taiwan (China); Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Dayeh University, 112 Shan-Jiau Road, Da-Tsuen, Changhua 515, Taiwan (China); Wang, M.-C. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-kung Road, Kaohsiung 80782, Taiwan (China) and Department of Materials Science and Engineering, National United University, 1 Lien-Da Road, Kung-ching Li, Miao Li 360, Taiwan (China)]. E-mail: mcwang@cc.kuas.edu.tw

    2007-05-31

    Drug releasing microspheres of poly(3-hydroxybutyric acid)/chitosan (PHB/CTS) with various compositions have been synthesized by both single and double emulsion methods, and collected by a freeze-drying process. In this study, gentamicin was used as an antibacterial medicine coated with PHB. The PHB/CTS microspheres of various compositions prepared by a single emulsion process (SEP) were identified as the major PHB phase together with a minor unknown Phase X by X-ray diffraction (XRD) and FT-IR. However, in the microspheres prepared using a double emulsion process (DEP) the dominant Phase was X and the minor phase was PHB. The size of the PHB/CTS microspheres prepared by SEP increased with the PHB/CTS ratio from 1 {mu}m for 1:1 to 2 {mu}m for 5:1. However, the size of the PHB/CTS microspheres prepared by DEP decreased with the PHB/CTS ratio from 1 {mu}m for 1:1 to 800 nm for 5:1.

  12. Structural and morphological studies on poly(3-hydroxybutyrate acid) (PHB)/chitosan drug releasing microspheres prepared by both single and double emulsion processes

    International Nuclear Information System (INIS)

    Shih, W.-J.; Chen, Y.-H.; Shih, C.-J.; Hon, M.-H.; Wang, M.-C.

    2007-01-01

    Drug releasing microspheres of poly(3-hydroxybutyric acid)/chitosan (PHB/CTS) with various compositions have been synthesized by both single and double emulsion methods, and collected by a freeze-drying process. In this study, gentamicin was used as an antibacterial medicine coated with PHB. The PHB/CTS microspheres of various compositions prepared by a single emulsion process (SEP) were identified as the major PHB phase together with a minor unknown Phase X by X-ray diffraction (XRD) and FT-IR. However, in the microspheres prepared using a double emulsion process (DEP) the dominant Phase was X and the minor phase was PHB. The size of the PHB/CTS microspheres prepared by SEP increased with the PHB/CTS ratio from 1 μm for 1:1 to 2 μm for 5:1. However, the size of the PHB/CTS microspheres prepared by DEP decreased with the PHB/CTS ratio from 1 μm for 1:1 to 800 nm for 5:1

  13. Preparation and Quality Control of 166Ho Labelled Polylactic Acid Microspheres for radiotherapy

    Czech Academy of Sciences Publication Activity Database

    Kropáček, Martin; Melichar, František; Klejzarová, Michaela; Ventruba, Jiří; Tomeš, Marek; Mirzajevová, Marcela

    2007-01-01

    Roč. 2, č. 332 (2007), s. 34-34 ISSN 1619-7070 R&D Projects: GA AV ČR 1QS100480501 Institutional research plan: CEZ:AV0Z10480505 Keywords : polylactic acid microspheres * 166Ho * liver tumour therapy Subject RIV: FR - Pharmacology ; Medidal Chemistry

  14. One-step preparation of zeolite silicalite-1 microspheres with adjustable macroporosity

    KAUST Repository

    Hua, Jia; Han, Yu

    2009-01-01

    silicalite-1 synthesis solution. During the hydrothermal synthesis, zeolite nanocrystals (∼ 100 nm) were formed and spontaneously assembled into uniform micrometer-sized (3-5 μm) spheres due to the presence of F127. The obtained microspheres possess

  15. Polymer blend microspheres for controlled drug release: the techniques for preparation and characterization: a review article.

    Science.gov (United States)

    Dasan, K Priya; Rekha, C

    2012-11-01

    The use of polymers and their microspheres in drug delivery is well known for they are being widely used in the field of drug delivery. The polymer entraps a drug which is to be released in a predesigned manner in the body through biodegradation. The blending of polymers is one way of modifying and enhancing the properties of polymer- based products which is also a cost effective procedure rather than developing a new product. The molecular weight of the polymer, the composition of the blend, the sphere porosity and size, and drug distribution are found to be controllable factors on which drug delivery depends. Polymer blends are obtained by allowing two polymers to combine as one material which has the advantage of two or more polymers. Polymer microspheres are small spherical particles with diameters in the micrometer range between 1μm to 1000μm which are manufactured from various natural and synthetic materials. Microspheres are used to administer medication in a rate- controlled manner and sometimes in a targeted manner. This review presents various polymer blend- combinations in different ratios, the different processing techniques adopted and the details of their characterization through examples found in a literature survey. The characterization of the different polymer blends or microspheres showed changes in structure, increase in drug loading, encapsulation efficiency, biocompatibility and low cytotoxicity.

  16. Two-Phase Diffusion Technique for the Preparation of Ultramacroporous/Mesoporous Silica Microspheres via Interface Hydrolysis, Diffusion, and Gelation of TEOS.

    Science.gov (United States)

    Ju, Minhua; Li, Yupeng; Yu, Liang; Wang, Chongqing; Zhang, Lixiong

    2018-02-06

    Honeycombed hierarchical ultramacroporous/mesoporous silica microspheres were prepared via the hydrolysis of TEOS in the oil-water interface, with subsequent diffusion and gelation in the acidic water-phase microdroplets with the assistance of a simple homemade microdevice. The diffusion of furfuryl alcohol (FA) also happened at a relatively high rate during the hydrolysis and diffusion of TEOS. Therefore, plenty of FA will be inside of the water microdroplets and form a decent number of polyfurfuryl alcohol (PFA) microparticles, thereby obtaining honeycombed hierarchical porosity silica microspheres with abundant ultramacroporous cavities and mesopores after calcination. It was found that the concentration of FA, residence time, and reaction temperature have significant effects on the porosity and pore size due to the influence on the diffusion rate and amount of FA in water-phase microdroplets. The honeycombed silica microspheres have obvious microscopic visible ultramacroporous cavities with the submicrometer cavity diameter as high as 85% porosity based on the rough overall volume of microsphere. N 2 adsorption-desorption isotherms show that the honeycombed hierarchical porosity silica microspheres have a high surface area of 602 m 2 g -1 , a mesopore volume of 0.77 cm 3 /g, and a mesopore porosity of 99.6% based on the total pore volume of N 2 adsorption-desorption. On the basis of the experiment results, a rational formation process of the honeycombed hierarchical porosity silica microspheres was deduced.

  17. [Preparation of vanilline cross-linked rhBMP-2/chitosan microspheres and its effect on mesenchymal stem cells].

    Science.gov (United States)

    Wu, Gui; Wang, Hai; Qiu, Guixing; Yu, Xin; Su, Xinlin; Ma, Pei; Yin, Bo; Wu, Zhihong

    2015-06-02

    To prepare rhBMP-2/chitosan microspheres (rhBMP-2 CMs) with vanilline as a cross-linking reagent and study the biocompatibility and drug release characteristic of microspheres in vitro. Emulsion cross-linking method was utilized to prepare rhBMP-2 CMs, Scanning electron microscope (SEM) was used to observe the microstructure of microspheres.Leaching solution of microspheres and blank culture medium were designated as experimental and control groups respectively. Both groups were cultured with human mesenchymal stem cells (hMSCs) to determine its cytotoxicity and its effect on the proliferation of hMSCs. Dynamic immersion method was used to examine the in vitro release characteristic of rhBMP-2. And the alkaline phosphatase (ALP) activity of hMSCs was determined to reveal the bioactivity of released rhBMP-2. The rhBMP-2 CMs were spherical under SEM.After treating with leaching solution for 24 and 48 h, there was no inter-group statistical difference in optical density (OD) values at both timepoints (24 h:0.72 ± 0.07 vs 0.73 ± 0.05, P > 0.05; 48 h:1.19 ± 0.11 vs 1.27 ± 0.06, P > 0.05). After culturing with leaching solution for 1, 3 and 7 days, the number of cells increased with time for both groups. And the OD values were not statistically different at each timepoint. Five milligram rhBMP-2 CMs soaked for 19 days with a gradual release of rhBMP-2. The concentration of rhBMP-2 was 216.1 ± 20.0 ng/ml at Day 19. At Days 3 and 7, the ALP activities of hMSCs were (0.50 ± 0.07) and (0.68 ± 0.06) µmol pNPP·min⁻¹·mg⁻¹ protein respectively and both were higher than that of blank culture medium group (0.14 ± 0.01) (P < 0.05). With an excellent biocompatibility, rhBMP-2 CMs may be an ideal carrier for control-released rhBMP-2 and encapsulated rhBMP-2 remains bioactive.

  18. Microencapsulation of protein drugs for drug delivery: strategy, preparation, and applications.

    Science.gov (United States)

    Ma, Guanghui

    2014-11-10

    Bio-degradable poly(lactide) (PLA)/poly(lactide-glycolide) (PLGA) and chitosan microspheres (or microcapsules) have important applications in Drug Delivery Systems (DDS) of protein/peptide drugs. By encapsulating protein/peptide drugs in the microspheres, the serum drug concentration can be maintained at a higher constant value for a prolonged time, or injection formulation can be changed to orally or mucosally administered formulation. PLA/PLGA and chitosan are most often used in injection formulation and oral formulation. However, in the preparation and applications of PLA/PLGA and chitosan microspheres containing protein/peptide drugs, the problems of broad size distribution and poor reproducibility of microspheres, and deactivation of protein during the preparation, storage and release, are still big challenges. In this article, the techniques for control of the diameter of microspheres and microcapsules will be introduced at first, then the strategies about how to maintain the bioactivity of protein drugs during preparation and drug release will be reviewed and developed in our research group. The membrane emulsification techniques including direct membrane emulsification and rapid membrane emulsification processes were developed to prepare uniform-sized microspheres, the diameter of microspheres can be controlled from submicron to 100μm by these two processes, and the reproducibility of products can be guaranteed. Furthermore, compared with conventional stirring method, the big advantages of membrane emulsification process were that the uniform microspheres with much higher encapsulation efficiency can be obtained, and the release behavior can be adjusted by selecting microsphere size. Mild membrane emulsification condition also can prevent the deactivation of proteins, which frequently occurred under high shear force in mechanical stirring, sonification, and homogenization methods. The strategies for maintaining the bioactivity of protein drug were

  19. Magnetic poly(N-propargylacrylamide) microspheres: preparation by precipitation polymerization and use in model click reactions

    Czech Academy of Sciences Publication Activity Database

    Macková, Hana; Proks, Vladimír; Horák, Daniel; Kučka, Jan; Trchová, Miroslava

    2011-01-01

    Roč. 49, č. 22 (2011), s. 4820-4829 ISSN 0887-624X R&D Projects: GA AV ČR KJB400500904; GA AV ČR(CZ) KAN401220801; GA ČR GAP503/10/0664 Institutional research plan: CEZ:AV0Z40500505 Keywords : click chemistry * magnetic * microspheres Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.919, year: 2011

  20. Preparation of monodisperse porous silica particles using poly(glycidyl methacrylate) microspheres as a template

    Czech Academy of Sciences Publication Activity Database

    Grama, Silvia; Horák, Daniel

    2015-01-01

    Roč. 64, Suppl. 1 (2015), S11-S17 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : microspheres * monodisperse * silica Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64%20Suppl%201/64_S11.pdf

  1. A method for preparing a sintered glass powder for manufacturing microspheres

    International Nuclear Information System (INIS)

    Budrick, R.G.; King, F.T.; Nolen, R.L. Jr.; Solomon, D.E.

    1975-01-01

    The invention relates to the manufacture of sintered glass-powder. It relates to a method comprising the step of forming a vitreous gel so that it contains an occluded substance adapted to expand when heated, said gel being subsequently dried, then crushed and sorted prior to being washed and dried again. Application to the manufacture of sintered glass-powder for forming microspheres adapted to contain a thermonuclear fuel [fr

  2. Influence of clay particles on microfluidic-based preparation of hydrogel composite microsphere

    Science.gov (United States)

    Hong, Joung Sook

    2016-05-01

    For the successful fabrication of a hydrogel composite microsphere, this study aimed to investigate the influence of clay particles on microsphere formation in a microfluidic device which has flow focusing and a 4.5:1 contraction channel. A poly alginic acid solution (2.0 wt.%) with clay particles was used as the dispersed phase to generate drops in an oil medium, which then merged with drops of a CaCl2 solution for gelation. Drop generations were observed with different flow rates and particles types. When the flow rate increased, drop generation was enhanced and drop size decreased by the build-up of more favorable hydrodynamic flow conditions to detach the droplets. The addition of a small amount of particles insignificantly changed the drop generation behavior even though it reduced interfacial tension and increased the viscosity of the solution. Instead, clays particles significantly affected hydro-gelation depending on the hydrophobicity of particles, which produced further heterogeneity in the shape and size of microsphere.

  3. Yolk-Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L-Lactate and Adenosine 5'-Triphosphate Disodium Salt: Application in Protein/Drug Delivery.

    Science.gov (United States)

    Ding, Guan-Jun; Zhu, Ying-Jie; Qi, Chao; Sun, Tuan-Wei; Wu, Jin; Chen, Feng

    2015-06-26

    A facile and environmentally friendly approach has been developed to prepare yolk-shell porous microspheres of calcium phosphate by using calcium L-lactate pentahydrate (CL) as the calcium source and adenosine 5'-triphosphate disodium salt (ATP) as the phosphate source through the microwave-assisted hydrothermal method. The effects of the concentration of CL, the microwave hydrothermal temperature, and the time on the morphology and crystal phase of the product are investigated. The possible formation mechanism of yolk-shell porous microspheres of calcium phosphate is proposed. Hemoglobin from bovine red cells (Hb) and ibuprofen (IBU) are used to explore the application potential of yolk-shell porous microspheres of calcium phosphate in protein/drug loading and delivery. The experimental results indicate that the as-prepared yolk-shell porous microspheres of calcium phosphate have relatively high protein/drug loading capacity, sustained protein/drug release, favorable pH-responsive release behavior, and a high biocompatibility in the cytotoxicity test. Therefore, the yolk-shell porous microspheres of calcium phosphate have promising applications in various biomedical fields such as protein/drug delivery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Synthesis of uniform-sized bimetallic iron-nickel phosphide nanorods

    International Nuclear Information System (INIS)

    Yoon, Ki Youl; Jang, Youngjin; Park, Jongnam; Hwang, Yosun; Koo, Bonil; Park, Je-Geun; Hyeon, Taeghwan

    2008-01-01

    We synthesized uniform-sized nanorods of iron-nickel phosphides from the thermal decomposition of metal-phosphine complexes. Uniform-sized (Fe x Ni 1-x ) 2 P nanorods (0≤x≤1) of various compositions were synthesized by thermal decomposition of Ni-trioctylphosphine (TOP) complex and Fe-TOP complex. By measuring magnetic properties, we found that blocking temperature and coercive field depend on Ni content in the nanorods. Both parameters were more sensitive to doping compared with bulk samples. - Graphical abstract: We synthesized uniform-sized nanorods of iron-nickel phosphides from thermal decomposition of metal-phosphine complexes. The magnetic studies showed that blocking temperature and coercive field depend on Ni content in the nanorods

  5. Preparation of high density (Th, U)O2 pellets by sol-gel microsphere pelletization and 1300 C air sintering

    International Nuclear Information System (INIS)

    Yamagishi, Shigeru; Takahashi, Yoshihisa

    1994-01-01

    The fabrication of high density (Th, U)O 2 pellets by the sol-gel microsphere pelletization (SGMP) process was studied. To prepare source ThO 2 -UO 3 microspheres, isopropyl alcohol was substituted for the water in gel and thereafter removed by evacuating and subsequently by heating at 200 C in air. After humidifying the microspheres up to the moisture content ranging 10-21%, they were compacted into a pellet under 150-500 MPa and sintered in air at 1300 C. Even at the relatively low temperature, the maximum density reached 98% TD or higher for the U/(Th+U) ratios of 5-20 mol%. Such high density products survived as firm pellets with a similarly high density of 99% TD during the reduction into (Th, U)O 2 in Ar-4% H 2 at 1300 C. ((orig.))

  6. Preparation of ThO2 sols having colloid-size distributions suitable for gelation into microspheres

    International Nuclear Information System (INIS)

    Yamagishi, Shigeru; Takahashi, Yoshihisa; Shiba, Koreyuki

    1984-01-01

    Production conditions of ThO 2 sols suitable for gelling into crackfree microspheres in an external gelation process were studied. The sols were prepared under pH control and colloid size distributions of the resulting sols were determined. The gelation was carried out by using hexone as a drop formation medium and ammonia as a gelling agent. The crackfree gelation was achieved by the use of ThO 2 sols produced under favorable pH, which were large in colloid size and high in colloid fraction. ''Preneutralization'' preceding the pH control is also important for the good sols. Analyzing the colloid fraction, colloid size and crystallite size of sol, it was found that, under the favorable pH, colloid nuclei generating at early stages grow in the form of single-crystals with their number kept constant and, after cooling, they exist as polycrystalline colloids. The mechanism of cracking is also discussed. (author)

  7. Preparation of carbon microspheres decorated with silver nanoparticles and their ability to remove dyes from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qingchun [Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Wu, Qingsheng, E-mail: qswu@tongji.edu.cn [Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

    2015-02-11

    Highlights: • Carbon microspheres decorated with silver nanoparticles (AgNP-CMSs) were prepared. • AgNP-CMSs show not only rapid and high adsorption capacity to methylene blue (MB) in water, but also excellent reusability. • It exhibits photocatalytic activity to Rhodamine B as well as MB under visible light. • The adsorption is from the ionic interactions but not the π–π conjugations. • The origin of photocatalysis is a surface plasmon resonance effect of AgNP on CMSs. - Abstract: Solid, but not hollow or porous, carbon microspheres decorated with silver nanoparticles (AgNP-CMSs) were prepared from silver nitrate and CMSs by a redox reaction at room temperature. The CMSs and AgNP-CMSs were characterized using X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and UV–vis spectrophotometry. Though with non-high specific surface area, the AgNP-CMSs exhibited a high adsorption capacity toward methylene blue (MB) in an aqueous solution. The AgNP-CMSs were able to remove all the MB from a solution of 30 mg/L MB in water within 1 min when the adsorbent concentration was 0.12 g/L. The AgNP-CMSs also exhibited good adsorption and photocatalytic activity in the decomposition of aqueous Rhodamine B as well as MB under visible light. FTIR was used to examine the interaction between AgNP-CMSs and MB, and the spectrum and more extra experiments suggest ionic interactions between cationic dyes and the negatively charged groups can be formed but not the presence of abundant π–π conjugations between dye molecules and the aromatic rings. The origin of the photocatalytic activity of AgNP-CMSs was attributed to a surface plasmon resonance (SPR) effect of the silver nanoparticles on the CMSs.

  8. Preparation of hollow microspheres of Ce{sup 3+} doped NiCo ferrite with high microwave absorbing performance

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hong-zhen, E-mail: duanhz2000@163.com; Zhou, Fang-ling; Cheng, Xia; Chen, Guo-hong; Li, Qiao-ling

    2017-02-15

    Hollow microspheres of Ce{sup 3+} doped NiCo-ferrites were synthesized by template-based-deposition and surface reaction method with carbon sphere as the template. The phase structure, morphology, magnetic properties and wave absorbing properties of the sample were characterized by X-ray powder diffraction(XRD), Scanning electronic microscopy(SEM), Vibration sample magnetometer (VSM) and a network vector analyzer (NVA), respectively. The results indicated that the particle size of the carbon sphere sample prepared by hydrothermal method was about 0.5 µm and the particle size of the Ni{sub 0.5}Co{sub 0.5}Fe{sub 2}O{sub 4} sample prepared by template-based method was about 300 nm. The influence of the amount of rare earth element on the magnetic and absorbing properties of sample was studied. The saturation magnetization and coercivity decreased gradually with the increase of the content of Ce. When the content of Ce was 0.02, the maximal saturation magnetization value and coercivity was 75.72 emu• g{sup −1} and 789.88 Oe, respectively. The associated ferrite hollow spheres have good absorbing performance, and the return loss value was −18.8 dB at 5500 MHz. - Highlights: • Hollow microspheres of Ce{sup 3+} doped NiCo-ferrites were synthesized by template-based-deposition and surface reaction method. • The influence of rare earth Ce{sup 3+} on the magnetic and absorbing properties of sample was studied. • When the content of Ce was 0.02, the maximal saturation magnetization value and coercivity was 75.72 emu• g{sup −1} and 789.88 Oe, respectively.

  9. Microspheres Prepared by Internal Gelation - Understanding of HMTA and urea reactions

    International Nuclear Information System (INIS)

    Robisson, A.C.; Dauby, J.; Grandjean, S.; Benay, G.; Modolo, G.

    2008-01-01

    Homogenous microspheres of minor actinide (hereafter MA) compounds are of interest to prevent the generation and dispersal of MA powder at the early stages of the fabrication of targets for homogenous or heterogeneous transmutation. Sol-gel routes are being investigated as one of the possible solutions for producing these homogeneous starting materials. This document describes internal gelation basis experiments led at Cea Marcoule and at the Institute for Energy Research Juelich dedicated to the synthesis of mixed compounds including MAs, particularly mixed actinide-actinide or mixed actinide-inert element compounds. Parameter studies were undertaken by simulating cations in order to scan a larger range of conditions and to optimise more easily gelation conditions. With these experiments, key parameters were put forward and the main successive reactions taking care during gelation were understood. (authors)

  10. Preparation of biodegradable magnetic microspheres with poly(lactic acid)-coated magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hong; Saatchi, Katayoun [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, 6T 1Z3 (Canada); Haefeli, Urs O. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3 (Canada)], E-mail: uhafeli@interchange.ubc.ca

    2009-05-15

    Poly(lactic acid) (PLA)-coated magnetic nanoparticles were made using uncapped PLA with free carboxylate groups. The physical properties of these particles were compared to those of oleate-coated or oleate/sulphonate bilayer (W40) coated magnetic particles. Magnetic microspheres (MMS) with the matrix material poly(lactide-co-glycolide) (PLGA) or PLA were then formed by the emulsion solvent extraction method with encapsulation efficiencies of 40%, 83% and 96% for oleate, PLA and oleate/sulfonate-coated magnetic particles, respectively. MMS made from PLA-coated magnetite were hemocompatible and produced no hemolysis, whereas the other MMS were hemolytic above 0.3 mg/mL of blood.

  11. Preparation of biodegradable magnetic microspheres with poly(lactic acid)-coated magnetite

    International Nuclear Information System (INIS)

    Zhao Hong; Saatchi, Katayoun; Haefeli, Urs O.

    2009-01-01

    Poly(lactic acid) (PLA)-coated magnetic nanoparticles were made using uncapped PLA with free carboxylate groups. The physical properties of these particles were compared to those of oleate-coated or oleate/sulphonate bilayer (W40) coated magnetic particles. Magnetic microspheres (MMS) with the matrix material poly(lactide-co-glycolide) (PLGA) or PLA were then formed by the emulsion solvent extraction method with encapsulation efficiencies of 40%, 83% and 96% for oleate, PLA and oleate/sulfonate-coated magnetic particles, respectively. MMS made from PLA-coated magnetite were hemocompatible and produced no hemolysis, whereas the other MMS were hemolytic above 0.3 mg/mL of blood.

  12. A study of factors affecting properties of AM/AMPS/NVP terpolymeric microspheres prepared by inverse suspension polymerization

    Science.gov (United States)

    Jiang, J. F.; Zhao, Q.; Lin, M. Q.; Wang, Y. F.; Dang, S. M.; Sun, F. F.

    2015-12-01

    Terpolymeric microspheres were synthesized by the inverse suspension polymerization of functional monomers including AMPS, NVP, and AM. The morphology and size of the obtained microspheres were measured by scanning electron microscopy (SEM) and optical microscopy. Furthermore, the swelling performances of the obtained microspheres were measured with alaser particle analyzer (LPA), and the thermal stability of the microspheres obtained was measured by differential thermal analysis (DSC-TG) and high temperature experiments involving microsphere/water dispersion. The results revealed that the extreme value of the microsphere size distribution decreased from 280 μm to 20 μm as the stirring rate increased from 175 rpm to 500 rpm. At temperatures below 25°C, the maximum achieved swelling ratio of the microspheres was 21, and the thermal stability of the terpolymer microspheres was significantly higher than that of the dipolymer microspheres. The terpolymer/water dispersions were kept at 120°C for 19d before any damage was observed.

  13. Molecularly imprinted microspheres and nanoparticles prepared using precipitation polymerisation method for selective extraction of gallic acid from Emblica officinalis.

    Science.gov (United States)

    Pardeshi, Sushma; Dhodapkar, Rita; Kumar, Anupama

    2014-03-01

    This paper reports the preparation of gallic acid (GA) molecularly imprinted polymers (MIPs) by the precipitation polymerisation and highlights the effect of porogen on particle size and specific molecular recognition properties. MIP, M-100 prepared in the porogen acetonitrile and MIP, M-75 prepared in a mixture of acetonitrile-toluene (75:25 v/v), resulted in the formation of microspheres with approximately 4μm particle size and surface area of 96.73m(2)g(-1) and nanoparticles (0.8-1000nm) and a surface area of 345.9m(2)g(-1), respectively. The Langmuir-Freundlich isotherm study revealed that M-75 has comparatively higher number of binding sites which are homogenous and has higher affinity for GA. The MIPs selectively recognised GA in presence of its structural analogues. Pure GA with percent recovery of 75 (±1.6) and 83.4 (±2.2) was obtained from the aqueous extract of Emblica officinalis by M-100 and M-75, respectively and hot water at 60°C served as the eluting solvent. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Preparation of core-shell structured CaCO3 microspheres as rapid and recyclable adsorbent for anionic dyes

    Science.gov (United States)

    Zhao, Mengen; Chen, Zhenhua; Lv, Xinyan; Zhou, Kang; Zhang, Jie; Tian, Xiaohan; Ren, Xiuli; Mei, Xifan

    2017-09-01

    Core-shell structured CaCO3 microspheres (MSs) were prepared by a facile, one-pot method at room temperature. The adsorbent dosage and adsorption time of the obtained CaCO3 MSs were investigated. The results suggest that these CaCO3 MSs can rapidly and efficiently remove 99-100% of anionic dyes within the first 2 min. The obtained CaCO3 MSs have a high Brunauer-Emmett-Teller surface area (211.77 m2 g-1). In addition, the maximum adsorption capacity of the obtained CaCO3 MSs towards Congo red was 99.6 mg g-1. We also found that the core-shell structured CaCO3 MSs have a high recycling capability for removing dyes from water. Our results demonstrate that the prepared core-shell structured CaCO3 MSs can be used as an ideal, rapid, efficient and recyclable adsorbent to remove dyes from aqueous solution.

  15. Semi-interpenetrating network of acrylamide-grafted-sodium alginate microspheres for controlled release of diclofenac sodium, preparation and characterization.

    Science.gov (United States)

    Al-Kahtani, Ahmed A; Sherigara, B S

    2014-03-01

    The semi-interpenetrating networks (semi-IPNs) of acrylamide grafted sodium alginate (AAm-g-NaAlg) microspheres (MPs) were prepared by emulsion-crosslinking method using glutaraldehyde (GA) as a crosslinking agent. The grafting of acrylamide onto sodium alginate was prepared by free-radical graft polymerization using ceric ammonium nitrate (CAN) as initiator at three acrylamide concentrations with monomer to polymer ratio of 1:1, 2:1 and 3:1, respectively. The grafting efficiency was found to be 91%. The produced MPs are almost spherical in nature with smooth surfaces. Diclofenac sodium (DS), an anti-inflammatory drug was successfully encapsulated into the MPs. The encapsulation efficiency was found to vary between 83% and 95%. The MPs were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The diffusion coefficient (D) was dependent upon the amount of crosslinking agent (GA) and amount of grafting ratio in the matrix. The rate of release was found to be dependent on the amount of GA, AAm:NaAlg grafting ratio and % drug loading in the MPs. The release data have been fitted to an empirical equation to investigate the diffusional exponent (n), which indicated that the release mechanism from MPs follows the super Case II transport. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Studies on the preparation and plasma spherodization of yttrium aluminosilicate glass microspheres for their potential application in liver brachytherapy

    Science.gov (United States)

    Sreekumar, K. P.; Saxena, S. K.; Kumar, Yogendra; Thiyagarajan, T. K.; Dash, Ashutosh; Ananthapadmanabhan, P. V.; Venkatesh, Meera

    2010-02-01

    Plasma spheroidization exploits the high temperature and high enthalpy available in the thermal plasma jet to melt irregularly shaped powder particles and quench them to get dense spherical particles. Plasma spheroidization is a versatile process and can be applied to metals, ceramics, alloys and composites to obtain fine spherical powders. Radioactive microspheres incorporated with high energetic beta emitting radioisotopes have been reported to be useful in the palliative treatment of liver cancer. These powders are to be prepared in closer range of near spherical morphology in the size range 20-35 microns. Inactive glass samples were prepared by heating the pre-calculated amount of glass forming ingredients in a recrystallized alumina crucible. The glass was formed by keeping the glass forming ingredients at 1700°C for a period of three hours to form a homogeneous melt. After cooling, the glass was recovered from the crucible by crushing and was subsequently powdered mechanically with the help of mortar and pestle. This powder was used as the feed stock for plasma spheroidization using an indigenously developed 40 kW plasma spray system. Experiments were carried out at various operating parameters. The operating parameters were optimised to get spheroidised particles. The powder was sieved to get the required size range before irradiation.

  17. Studies on the preparation and plasma spherodization of yttrium aluminosilicate glass microspheres for their potential application in liver brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sreekumar, K P; Saxena, S K; Kumar, Yogendra; Thiyagarajan, T K; Dash, Ashutosh; Ananthapadmanabhan, P V; Venkatesh, Meera, E-mail: nair.sreekumar@gmail.co [Laser and Plasma Technology Division, Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)

    2010-02-01

    Plasma spheroidization exploits the high temperature and high enthalpy available in the thermal plasma jet to melt irregularly shaped powder particles and quench them to get dense spherical particles. Plasma spheroidization is a versatile process and can be applied to metals, ceramics, alloys and composites to obtain fine spherical powders. Radioactive microspheres incorporated with high energetic beta emitting radioisotopes have been reported to be useful in the palliative treatment of liver cancer. These powders are to be prepared in closer range of near spherical morphology in the size range 20-35 microns. Inactive glass samples were prepared by heating the pre-calculated amount of glass forming ingredients in a recrystallized alumina crucible. The glass was formed by keeping the glass forming ingredients at 1700{sup 0}C for a period of three hours to form a homogeneous melt. After cooling, the glass was recovered from the crucible by crushing and was subsequently powdered mechanically with the help of mortar and pestle. This powder was used as the feed stock for plasma spheroidization using an indigenously developed 40 kW plasma spray system. Experiments were carried out at various operating parameters. The operating parameters were optimised to get spheroidised particles. The powder was sieved to get the required size range before irradiation.

  18. Studies on the preparation and plasma spherodization of yttrium aluminosilicate glass microspheres for their potential application in liver brachytherapy

    International Nuclear Information System (INIS)

    Sreekumar, K P; Saxena, S K; Kumar, Yogendra; Thiyagarajan, T K; Dash, Ashutosh; Ananthapadmanabhan, P V; Venkatesh, Meera

    2010-01-01

    Plasma spheroidization exploits the high temperature and high enthalpy available in the thermal plasma jet to melt irregularly shaped powder particles and quench them to get dense spherical particles. Plasma spheroidization is a versatile process and can be applied to metals, ceramics, alloys and composites to obtain fine spherical powders. Radioactive microspheres incorporated with high energetic beta emitting radioisotopes have been reported to be useful in the palliative treatment of liver cancer. These powders are to be prepared in closer range of near spherical morphology in the size range 20-35 microns. Inactive glass samples were prepared by heating the pre-calculated amount of glass forming ingredients in a recrystallized alumina crucible. The glass was formed by keeping the glass forming ingredients at 1700 0 C for a period of three hours to form a homogeneous melt. After cooling, the glass was recovered from the crucible by crushing and was subsequently powdered mechanically with the help of mortar and pestle. This powder was used as the feed stock for plasma spheroidization using an indigenously developed 40 kW plasma spray system. Experiments were carried out at various operating parameters. The operating parameters were optimised to get spheroidised particles. The powder was sieved to get the required size range before irradiation.

  19. Preparation and characterization of molecularly-imprinted magnetic microspheres for adsorption of 2,4,6-trichlorophenol from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ping; Pan, Jianming; Yan, Yongsheng [Jiangsu University, Zhenjiang (China); Sun, Qilong; Li, Jianfeng; Tan, Zhenjiang [Jilin Normal University, Siping (China)

    2015-04-15

    Magnetic molecularly imprinted microspheres (MMIS) were successfully prepared by suspension polymerization, and then as-prepared MMIS were used as adsorbents for selective recognition of 2,4,6-trichlorophenol (2,4,6-TCP) from aqueous solutions. The results composites were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The results demonstrated that MMIS possesses porous spherical morphology, and exhibits good thermal stability and magnetic property (Ms=10.14 emu g{sup -1}). Then batch mode of binding experiments was used to determine the equilibrium, kinetics and selectivity recognition. The Langmuir isotherm model fitted the equilibrium data better than did the Freundlich model, and the maximum adsorption capacity on MMIS was about 1.7 times higher than that of MNIS. Kinetics behaviors of MMIS were well described by the pseudo-second-order model. MMIS possessed outstanding selectivity recognition for 2,4,6-TCP in the presence of other competitive phenols (such as sesamol, 3-CP, thymol, 2,4-DCP). Furthermore, the reusability performance of MMIS showed about 17.53% loss after five repeated cycles. Finally, the MMIS were successfully applied to the selective extraction of 2,4,6-TCP from the vegetable samples.

  20. Synthesis of magnetic polymeric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

    2010-05-13

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  1. Synthesis of magnetic polymeric microspheres

    International Nuclear Information System (INIS)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I

    2010-01-01

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  2. Preparation and in vitro and in vivo evaluation of HupA PLGA microsphere.

    Science.gov (United States)

    Ye, Liang; Fu, Fenghua; Liu, Wanhui; Sun, Kaoxiang; Li, Youxin; He, Jie; Yu, Xin; Yu, Pengfei; Tian, Jingwei

    2013-03-01

    Acetylcholinesterase inhibitors (AChEIs), including Huperzine A (HupA), have been the mainstay of treatment for Alzheimer's disease (AD). However, AChEIs can cause gastrointestinal side effects, which has been related to the high Cmax and short tmax after oral administration. Clinical trials have verified that extended-release formulation with lower Cmax and prolonged tmax, such as rivastigmine patch, could perform a similar efficacy with significantly improved tolerability compared with the oral formulations. In this study, we developed an extended-release microspheres formulation of HupA (called as HAM) with poly(lactide-co-glycolide) (PLGA) as drug carrier. HAM has showed the loading rate as 1.35% (w/w) and yielded 42% with mean particle size at 72.6 μm. In vitro and in vivo pharmacokinetics studies have showed that HAM produced a relatively smooth and continuous drug concentration in 14 days. Furthermore, in vivo pharmacokinetics data have demonstrated that the Cmax was lower and the tmax was considerably later in single intramuscular administration of HAM (1,000 μg/kg) than the counterparts in single intragastric administration of HAT (75 μg/kg/d). Meanwhile, HAM has performed a continuous inhibition to brain AChE activity in normal rats and improvement of memory deficit in Aβ1-40 i.c.v. infused AD rat model for 14 days. The results have suggested that HAM has performed good extended-release properties and good prolonged pharmacological efficacy in vivo in the 2-week period, and could exert a similar efficacy with significantly lowered gastrointestinal side effects as compared with oral formulation.

  3. Microfluidic Fabrication of Morphology-Controlled Polymeric Microspheres of Blends of Poly(4-butyltriphenylamine and Poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Saki Yoshida

    2018-04-01

    Full Text Available Multicomponent polymer particles with specific morphology are promising materials exhibiting novel functionality which cannot be obtained with single-component polymer particles. Particularly, the preparation of such kinds of polymer particles involving electrically or optically active conjugated polymers with uniform size is a challenging subject due to their intense demands. Here, microspheres of binary polymer blend consisting of poly(4-butyltriphenylamine (PBTPA/poly(methyl methacrylate (PMMA (1:1 in weight were produced via a microfluidic emulsification with a Y-shaped microreactor, and a subsequent solvent evaporation method. The flow rate of the dispersed phase (polymer solution was fixed to 7 µL/min, and 140 or 700 µL/min of the flow rate of the continuous phase (aqueous 0.6 wt % of poly(vinyl alcohol (PVA solution was utilized to produce the dispersion with different diameter. The concentration of dispersed phase was adjusted to 0.1 or 1.0 w/v%. Core-shell, Janus and dumbbell type microspheres were obtained dependent on the flow rate of continuous phase. Incomplete core-shell type microspheres were produced for the blend involving low molecular weight PMMA. Complex Janus and core-shell type microspheres were fabricated by the addition of sodium dodecyl sulfate (SDS to continuous phase. It is found that final morphologies are strongly dependent on the initial conditions of dispersion including the particle size suggesting that the morphologies are governed by the kinetical factors together with the conventionally accepted thermodynamic ones.

  4. Preparation of Hierarchical BiOBr Microspheres for Visible Light-Induced Photocatalytic Detoxification and Disinfection

    Directory of Open Access Journals (Sweden)

    Ayla Ahmad

    2016-01-01

    Full Text Available Photocatalytic degradation is a promising alternative to traditional wastewater treatment methods. Recently developed visible light-responsive photocatalyst, BiOBr, has attracted extensive attentions. Hereby, a detailed investigation of application of BiOBr to bacterial inactivation and organic pollutants degradation is reported. Hydrothermal catalyst was prepared using template-free method. While, for solvothermal synthesis, CTAB was used as a template. Results indicate a higher photocatalytic activity by the solvothermally prepared catalyst. Solvothermally prepared BiOBr exhibited high photocatalytic activities in both water detoxification and disinfection.

  5. Preparation and dual microwave-absorption properties of carboxylic poly(arylene ether nitrile)/Fe3O4 hybrid microspheres

    International Nuclear Information System (INIS)

    Ma Zhen; Meng Fanbin; Zhao Rui; Zhan Yingqing; Zhong Jiachun; Liu Xiaobo

    2012-01-01

    The carboxylic poly(arylene ether nitrile)/Fe 3 O 4 hybrid microspheres were prepared via solvothermal method. The carboxylic poly(arylene ether nitrile) (PEN-COOH) was introduced into the Fe 3 O 4 microspheres by chemisorption with mass content up to 15% as defined by infrared spectra and thermal gravimetric analysis. The hybrid sphere is of hierarchical polymer–inorganic microstructure as observed by transmission electron microscopy. The microwave-absorption of the sample owns a shifting peak and a special immobilized peak with the variation of absorber thickness from 3 to 5 mm. Maximum microwave-absorption of the product is capable of over −30 dB in the range of 10–12 GHz. By proposed equivalent filter circuit model, the immobilized peak was attributed to the ordered nanostructure where the Fe 3 O 4 nanocrystals were isolated by PEN-COOH. The product has the potential to be applied as microwave absorber with high microwave-absorption, good dispersibility and robust polymer–inorganic interfacial adherence. - Highlights: ► We prepared poly(arylene ether nitrile)/Fe 3 O 4 hybrid microspheres with hierarchical polymer–inorganic nanostructure. ► A shifting and an immobilized microwave absorbing peaks were observed on the sample. ► Possible mechanism was proposed on the basis of electromagnetic data.

  6. Preparation and characterization of sol-gel derived (Th{sub x}Ce{sub 1-x})O{sub 2} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cetinkaya, Berkan; Tel, Hueseyin [Ege Univ., Izmir (Turkey). Inst. of Nuclear Sciences

    2018-04-01

    (Th{sub x}Ce{sub 1-x})O{sub 2} microspheres (x = 0.50, 0.75 and 0.95) with high homogeneity were prepared via sol-gel technique, starting from the initial chemical materials Th(NO{sub 3}){sub 4} . 5H{sub 2}O and (NH{sub 4}){sub 2}[Ce(NO{sub 3}){sub 6}]. The sols were prepared by addition of ammonia under pH and temperature control. Sols were gelated to spherical form in a gelation system consisting of peristaltic pump, flow regulator, nozzle and a glass column. To obtain crack-free spheres suitable for gelation, source sols neutralization conditions, drop formation and pre-hardening medium were investigated and the optimum conditions were determined. After aging, washing and drying steps, gel microspheres were characterized. For this purpose, thermal behaviors of spheres were investigated with TG/DTA analysis. Dried microspheres at 80 C were calcined at three different temperatures, namely 450 C, 800 C and 1150 C, and crystal parameters were calculated from XRD data. BET specific surface area and BJH porosity analyses were also carried out.

  7. Preparation of microspheres containing methyl methacrylate (MMA) with magnetic nanoparticles; Preparacao de microesferas contendo metacrilato de metila (PMMA) com nanoparticulas magneticas

    Energy Technology Data Exchange (ETDEWEB)

    Feuser, P.E.; Souza, M.N. de, E-mail: paulofeuser@hotmail.co, E-mail: nele@eq.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Engenharia Quimica

    2010-07-01

    Magnetic nanoparticles have found many technological applications and has been intensively studied due to its special magnetic properties. In most biomedical applications, microspheres containing magnetic nanoparticles is used as a vehicle for transporting drugs, presenting several advantages when compared to other conventional methods. PMMA is a polymer which has biocompatibility and can be used for the encapsulation of magnetic nanoparticles, showing a great degree of saturation magnetization. PMMA microparticles containing magnetic nanoparticles were prepared by suspension polymerization. Polymers containing magnetic nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetization, thermogravimetric analysis, optical microscopy, chromatography gel permeation, analysis of particle size - malversizer 2000 (Malvern Instruments). The average size of magnetic nanoparticles was approximately 150 {mu}m and depending on the amount of magnetic nanoparticles in the reaction medium Mw of microspheres can be altered. (author)

  8. Optimized spray drying process for preparation of one-step calcium-alginate gel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Popeski-Dimovski, Riste [Department of physic, Faculty of Natural Sciences and Mathematics, “ss. Cyril and Methodius” University, Arhimedova 3, 1000 Skopje, R. Macedonia (Macedonia, The Former Yugoslav Republic of)

    2016-03-25

    Calcium-alginate micro particles have been used extensively in drug delivery systems. Therefore we establish a one-step method for preparation of internally gelated micro particles with spherical shape and narrow size distribution. We use four types of alginate with different G/M ratio and molar weight. The size of the particles is measured using light diffraction and scanning electron microscopy. Measurements showed that with this method, micro particles with size distribution around 4 micrometers can be prepared, and SEM imaging showed that those particles are spherical in shape.

  9. Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery in Vivo.

    Science.gov (United States)

    Ma, Da; Tian, Shaomin; Baryza, Jeremy; Luft, J Christopher; DeSimone, Joseph M

    2015-10-05

    To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery in vivo is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery in vivo. "Blank" hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to "blank" nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency in vitro. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for in vivo siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels.

  10. Application of gel microsphere processes to preparation of Sphere-Pac nuclear fuel

    International Nuclear Information System (INIS)

    Haas, P.A.; Notz, K.J.; Spence, R.D.

    1978-01-01

    Sphere-Pac fabrication of nuclear fuels using two or more sizes of oxide or carbide spheres is ideally suited to nonproliferation-fuel cycles and remote refabrication. The sizes and compositions of spheres necessary for such fuel cycles have not been commonly prepared; therefore, modifications of sol-gel processes to meet these requirements are being developed and demonstrated

  11. Variations in polyethylene glycol brands and their influence on the preparation process of hydrogel microspheres

    DEFF Research Database (Denmark)

    Wöhl-Bruhn, Stefanie; Bertz, Andreas; Kuntsche, Judith

    2013-01-01

    differences in the salt composition and molecular weight distribution of the polymers which can explain the results from the production process. The results illustrate that the range of product specifications may not always be tight enough to avoid variability in pharmaceutical processes like the preparation...

  12. Review: microspheres for radioembolization therapy

    International Nuclear Information System (INIS)

    Zhao Mingqiang; Xu Shuhe

    2007-12-01

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  13. Review: microspheres for radioembolization therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mingqiang, Zhao; Shuhe, Xu [China Inst. of Atomic Energy, Beijing (China)

    2007-12-15

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  14. Electrophoretic Ink Display Prepared by Jelly Fig Pectin/Gelatin Microspheres

    Directory of Open Access Journals (Sweden)

    Wing-Ming Chou

    2015-05-01

    Full Text Available A brand new Bio-Electronic ink (Bio-E ink display device was prepared and characterized in this study. Semiconductor material, copper phthalocyanine (CuPc was modified by cationic surfactants, cetylpyridinium chloride (CPC, as the core material, and the shell of capsule was prepared by jelly fig pectin, gelatin and sodium dodecyl sulphate (SDS. Here, jelly fig pectin was provided as the shell material for the first time. Chemical structure of the modified CuPc was characterized by Fourier Transform Infrared Spectrometer (FTIR. The core-shell microcapsules were achieved by coacervation method in an oil/water (O/W emulsion system. The particle size and morphology of microcapsules were affected by the concentrations of SDS and pH values of the O/W emulsion system. A new microcapsule-based electrophoretic display device was presented. Its image display ability of the microcapsules electrophoretic device was presented as appropriated electric power was applied, and the response time was 0.06 sec under 0.1 V/mm of electric field. Moreover, we found that its image contrast ratio of display device was influenced by the particle sizes of the microcapsules.

  15. Temperature influence in crystallinity of polymer microspheres

    International Nuclear Information System (INIS)

    Rezende, Cristiane de P.; Novack, Katia M.

    2011-01-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  16. Ag/α-Fe2O3 hollow microspheres: Preparation and application for hydrogen peroxide detection

    Science.gov (United States)

    Kang, Xinyuan; Wu, Zhiping; Liao, Fang; Zhang, Tingting; Guo, Tingting

    2015-09-01

    In this paper, we demonstrated a simple approach for preparing α-Fe2O3 hollow spheres by mixing ferric nitrate aqueous and glucose in 180 °C. The glucose was found to act as a soft template in the process of α-Fe2O3 hollow spheres formation. Ag/α-Fe2O3 hollow nanocomposite was obtained under UV irradiation without additional reducing agents or initiators. Synthesized Ag/α-Fe2O3 hollow composites exhibited remarkable catalytic performance toward H2O2 reduction. The electrocatalytic activity mechanism of Ag/α-Fe2O3/GCE were discussed toward the reduction of H2O2 in this paper.

  17. Development of the method of the preparation of albumin microspheres labelled 188-rhenium

    International Nuclear Information System (INIS)

    Dyomin, D.N.; Petriev, V.M.

    2001-01-01

    The basis of effective and wide usage of radioisotope methods in diagnostic and therapy of tumoral and not tumoral diseases is development of new radiopharmaceuticals, described by high functional value and safety. The efficiency and safety of radiopharmaceuticals are defined by the nuclear - physical characteristics of radionuclides, and also physicochemical and biological properties of carriers for selective delivery of radionuclides. Therefore an important direction in radiopharmacy is the search, the development and estimation of particular properties radiopharmaceuticals for radiotherapy of tumoral and not tumoral diseases, where the main thing is the choice of optimal carriers and radionuclides. At present time two types of carriers are used for delivery radionuclides: soluble preparations and insoluble so-called microparticles. (authors)

  18. Rifapentine-linezolid-loaded PLGA microspheres for interventional therapy of cavitary pulmonary tuberculosis: preparation and in vitro characterization.

    Science.gov (United States)

    Huang, Jieyun; Chen, Zhi; Li, Ying; Li, Li; Zhang, Guangyu

    2017-01-01

    In this study, we aimed to design controlled-release microspheres for the treatment of cavitary pulmonary tuberculosis (TB) for solving the issues of poor drug delivery and short duration maintained at effective drug concentration during bronchoscopic interventional therapy. We fabricated rifapentine-linezolid-loaded poly(lactic acid-co-glycolic acid) microspheres (RLPMs) using the oil-in-water emulsion solvent evaporation method and assessed their in vitro release as well as the bronchial mucosal retention characteristics. The microspheres are spherical in shape with a circular concave on the surface. The particle size of RLPMs was 27.38±1.28 μm. The drug loading of rifapentine and linezolid was 18.51±0.26 and 8.42%±0.24%, respectively, while the encapsulation efficiencies were 55.53±0.78 and 16.87%±0.47%, respectively (n=3). During the burst release phase of the in vitro release test, 21.37%±0.68% rifapentine was released in 3 days and 43.56%±2.54% linezolid was released in 1 day. Then, both the drugs entered the sustained release phase. Finally, the cumulative percentage release of rifapentine and linezolid in 14 days was 27.61±1.52 and 51.01%±3.31%, respectively (n=3). Bronchoscopic observation revealed that the controlled-release microspheres could slowly release the drugs and retain them on the surface of bronchial mucosa of canines for 20 days. These results indicated that the fabricated microspheres exhibited a significant sustained release effect and could effectively retain the drugs on the surface of bronchial mucosa. Therefore, this study provides a theoretical and practical foundation for the development of fabricated microspheres loaded with multiple anti-TB drugs in the bronchoscopic interventional therapy of cavity pulmonary TB.

  19. Ag/α-Fe2O3 hollow microspheres: Preparation and application for hydrogen peroxide detection

    International Nuclear Information System (INIS)

    Kang, Xinyuan; Wu, Zhiping; Liao, Fang; Zhang, Tingting; Guo, Tingting

    2015-01-01

    In this paper, we demonstrated a simple approach for preparing α-Fe 2 O 3 hollow spheres by mixing ferric nitrate aqueous and glucose in 180 °C. The glucose was found to act as a soft template in the process of α-Fe 2 O 3 hollow spheres formation. Ag/α-Fe 2 O 3 hollow nanocomposite was obtained under UV irradiation without additional reducing agents or initiators. Synthesized Ag/α-Fe 2 O 3 hollow composites exhibited remarkable catalytic performance toward H 2 O 2 reduction. The electrocatalytic activity mechanism of Ag/α-Fe 2 O 3 /GCE were discussed toward the reduction of H 2 O 2 in this paper. - Graphical abstract: Glucose is carbonized as carbon balls in the 180 °C hydrothermal carbonization process, which plays a role of a soft template. Carbon spherical shell is rich in many hydroxyls, which have good hydrophilicity and surface reactivity. When Fe(NO 3 ) 3 is added to the aqueous solution of Glucose, the hydrophilic -OH will adsorb Fe 3+ to form coordination compound by coordination bond. α-FeOOH is formed on the surface of carbon balls by hydrothermal reaction. After calcination at 500 °C, carbon spheres react with oxygen to form carbon dioxide, which disappears in the air. Meanwhile α-FeOOH is calcined to form α-Fe 2 O 3 hollow spheres.

  20. Controlled release system for ametryn using polymer microspheres: Preparation, characterization and release kinetics in water

    International Nuclear Information System (INIS)

    Grillo, Renato; Pereira, Anderson do Espirito Santo; Ferreira Silva de Melo, Nathalie; Porto, Raquel Martins; Feitosa, Leandro Oliveira; Tonello, Paulo Sergio; Dias Filho, Newton L.; Rosa, Andre Henrique; Lima, Renata; Fraceto, Leonardo Fernandes

    2011-01-01

    The purpose of this work was to develop a modified release system for the herbicide ametryn by encapsulating the active substance in biodegradable polymer microparticles produced using the polymers poly(hydroxybutyrate) (PHB) or poly(hydroxybutyrate-valerate) (PHBV), in order to both improve the herbicidal action and reduce environmental toxicity. PHB or PHBV microparticles containing ametryn were prepared and the efficiencies of herbicide association and loading were evaluated, presenting similar values of approximately 40%. The microparticles were characterized by scanning electron microscopy (SEM), which showed that the average sizes of the PHB and PHBV microparticles were 5.92 ± 0.74 μm and 5.63 ± 0.68 μm, respectively. The ametryn release profile was modified when it was encapsulated in the microparticles, with slower and more sustained release compared to the release profile of pure ametryn. When ametryn was associated with the PHB and PHBV microparticles, the amount of herbicide released in the same period of time was significantly reduced, declining to 75% and 87%, respectively. For both types of microparticle (PHB and PHBV) the release of ametryn was by diffusion processes due to anomalous transport (governed by diffusion and relaxation of the polymer chains), which did not follow Fick's laws of diffusion. The results presented in this paper are promising, in view of the successful encapsulation of ametryn in PHB or PHBV polymer microparticles, and indications that this system may help reduce the impacts caused by the herbicide, making it an environmentally safer alternative.

  1. Preparation and characterization of SiO2 microspheres doped with CoFe2O4 nanocrystals

    Czech Academy of Sciences Publication Activity Database

    Tyrpekl, V.; Poltierová Vejpravová, J.; Plocek, Jiří; Nižňanský, D.

    2010-01-01

    Roč. 28, č. 1 (2010), s. 129-137 ISSN 0137-1339 R&D Projects: GA ČR GA106/07/0949 Institutional research plan: CEZ:AV0Z40320502 Keywords : sol-gel * microemulsion * cobalt ferrite * microspheres * nanocomposite Subject RIV: CA - Inorganic Chemistry Impact factor: 0.336, year: 2010

  2. Rifapentine-linezolid-loaded PLGA microspheres for interventional therapy of cavitary pulmonary tuberculosis: preparation and in vitro characterization

    Directory of Open Access Journals (Sweden)

    Huang J

    2017-03-01

    Full Text Available Jieyun Huang,1,* Zhi Chen,2,* Ying Li,3 Li Li,2 Guangyu Zhang2 1The Second Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China; 2Institute for Tuberculosis Research, The 309th Hospital of Chinese PLA, Beijing, People’s Republic of China; 3Department of Drug Delivery Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China *These authors contributed equally to this work Abstract: In this study, we aimed to design controlled-release microspheres for the treatment of cavitary pulmonary tuberculosis (TB for solving the issues of poor drug delivery and short duration maintained at effective drug concentration during bronchoscopic interventional therapy. We fabricated rifapentine-linezolid-loaded poly(lactic acid-co-glycolic acid microspheres (RLPMs using the oil-in-water emulsion solvent evaporation method and assessed their in vitro release as well as the bronchial mucosal retention characteristics. The microspheres are spherical in shape with a circular concave on the surface. The particle size of RLPMs was 27.38±1.28 µm. The drug loading of rifapentine and linezolid was 18.51±0.26 and 8.42%±0.24%, respectively, while the encapsulation efficiencies were 55.53±0.78 and 16.87%±0.47%, respectively (n=3. During the burst release phase of the in vitro release test, 21.37%±0.68% rifapentine was released in 3 days and 43.56%±2.54% linezolid was released in 1 day. Then, both the drugs entered the sustained release phase. Finally, the cumulative percentage release of rifapentine and linezolid in 14 days was 27.61±1.52 and 51.01%±3.31%, respectively (n=3. Bronchoscopic observation revealed that the controlled-release microspheres could slowly release the drugs and retain them on the surface of bronchial mucosa of canines for 20 days. These results indicated that the fabricated microspheres exhibited

  3. Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples

    International Nuclear Information System (INIS)

    Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Cao, Rong; Sun, Hao; Huang, Chaonan; Chen, Jiping

    2015-01-01

    Highlights: • BPA imprinted polymer microspheres were prepared by Pickering emulsion polymerization. • Regular spherical shape and narrow diameter distribution. • Good specific adsorption capacity for BPA. • Good class-selectivity and clean-up efficiency for bisphenols in human urine under SPE mode. • Good recoveries and sensitivity for bisphenols using the MIPMS-SPE coupled with HPLC-DAD method. - Abstract: The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption–desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30–60 μm), a specific surface area (S BET ) of 281.26 m 2 g −1 and a total pore volume (V t ) of 0.459 cm 3 g −1 . Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2–2.2 ng mL −1 . The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL −1 for each BP) were in the range of 81.3–106.7% with RSD values below 8.3%

  4. Degradation and protein release properties of microspheres prepared from biodegradable poly(lactide-co-glycolide) and ABA triblock copolymers: influence of buffer media on polymer erosion and bovine serum albumin release.

    Science.gov (United States)

    Bittner, B; Witt, C; Mäder, K; Kissel, T

    1999-08-05

    The aim of the present study was to investigate the influence of the chemical insertion of poly(ethylene oxide), PEO, into a poly(lactide-co-glycolide), PLG, backbone on the mechanisms of in vitro degradation and erosion of the polymer. For this purpose microspheres prepared by a modified W/O/W double emulsion technique using ABA triblock copolymers, consisting of PLG A-blocks attached to central PEO B-blocks were compared with microspheres prepared from PLG. Due to their molecular architecture the ABA triblock copolymers differed in their erosion and degradation behavior from PLG. Degradation occurred faster in the ABA polymers by cleavage of ester bonds inside the polymer backbone. Even erosion was shown to start immediately after incubation in different buffer media. By varying pH and ionic strength of the buffer it was found that both mass loss and molecular weight decay were accelerated in alkaline and acidic pH in the case of the ABA triblock copolymers. Although the pH of the medium had a moderate influence on the degradation of PLG, the molecular weight decay was not accompanied by a mass loss during the observation time. In a second set of experiments we prepared bovine serum albumin, BSA, loaded microspheres from both polymers. The release of BSA from ABA microspheres under in vitro conditions parallels the faster swelling and erosion rates. This could be confirmed by electron paramagnetic resonance, EPR, measurements with spin labeled albumin where an influx of buffer medium into the ABA microspheres was already observed within a few minutes. In contrast, PLG microspheres revealed a burst release without any erosion. The current study shows that the environmental conditions affected the degradation and erosion of the pure polymer microspheres in the same way as the release of the model protein. This leads to the conclusion that the more favorable degradation profile of the ABA triblock copolymers was responsible for the improvement of the release profile.

  5. Thermal analysis of iron hydroxide microspheres

    International Nuclear Information System (INIS)

    Turcanu, C.N.; Cornescu, M.

    1979-03-01

    The thermal treatment is an important step in the preparative technology of the iron oxids microspheres with well established mechanical, physical and chemical characteristics. The first indications on the heating procedure have been obtained from the thermal analysis on iron hydroxide microspheres prepared by the support precipitation and internal gelification methods. (author)

  6. In situ one-pot preparation of superparamagnetic hydrophilic porous microspheres for covalently immobilizing penicillin G acylase to synthesize amoxicillin

    Science.gov (United States)

    Xue, Ping; Gu, Yaohua; Su, Weiguang; Shuai, Huihui; Wang, Julan

    2016-01-01

    Magnetic hydrophilic porous microspheres were successfully one-pot synthesized for the first time via in situ inverse suspension polymerization of glycidyl methacrylate, N,N‧-methylene bisacrylamide and 2-hydroxyethyl methacrylate in the presence of Fe3+ and Fe2+ dispersed in formamide, which were denoted as magnetic Fe3O4-GMH microspheres. The morphology and properties of magnetic Fe3O4-GMH microspheres were characterized by SEM, VSM, XRD, FTIR, and so on. The formamide content had an important influence on the morphology of Fe3O4-GMH, and nearly perfectly spherical Fe3O4-GMH particles were formed when the amount of formamide was 15 ml. The diameters of the microspheres were in the range of 100-200 μm and Fe3O4-GMH exhibited superparamagnetic behavior with the saturation magnetization of 5.44 emu/g. The specific surface area of microspheres was 138.7 m2/g, the average pore diameter and pore volume were 15.1 nm and 0.60 cm3/g, respectively. The content of oxirane groups on Fe3O4-GMH was 0.40 mmol/g. After penicillin G acylase (PGA) was covalently immobilized on Fe3O4-GMH microspheres, the catalytic performance for amoxicillin synthesis by 6-aminopenicillanic acid and D-hydroxyphenylglycine methyl ester was largely improved. As a result, 90.1% amoxicillin yield and 1.18 of the synthesis/hydrolysis (S/H) ratio were achieved on PGA/Fe3O4-GMH with ethylene glycol as solvent, but only 62.6% amoxicillin yield and 0.37 of the S/H ratio were obtained on free PGA under the same reaction conditions. Furthermore, the amoxicillin yield and S/H ratio were still kept at 88.2% and 1.06, respectively after the immobilized PGA was magnetically separated and recycled for 10 times, indicating that PGA/Fe3O4-GMH had a very good reusability.

  7. Controlling silk fibroin microspheres via molecular weight distribution

    International Nuclear Information System (INIS)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui; Zhang, Ke-Qin

    2015-01-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K 2 HPO 4 –KH 2 PO 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

  8. 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.

  9. UO2 microspheres obtainment through the internal gelation methods

    International Nuclear Information System (INIS)

    Sterba, M.E.; Gomez Constenla, A.

    1987-01-01

    UO 2 microspheres obtainment process through the internal gelation method which allows the spheres' obtainment of uniform size is detailed herein, varying the same among 0.3 and 1.7 mm of diameter. The sintered density reaches 10.78 g/cm 3 , permitting the fuels fabrication dispersed and vibro-compacted fuels. The trichloroethylene use implementation as gelation agent is described, thus reducing the number of stages in the microspheres fabrication. At the same time, the uranium sun composition has been modified so as to be compatible with the use solvent. (Author)

  10. Preparation and crystallization of hollow α-Fe2O3 microspheres following the gas-bubble template method

    International Nuclear Information System (INIS)

    Valladares, L. de los Santos; León Félix, L.; Espinoza Suarez, S.M.; Bustamante Dominguez, A.G.; Mitrelias, T.; Holmes, S.; Moreno, N.O.; Albino Aguiar, J.; Barnes, C.H.W.

    2016-01-01

    In this work we report the formation of hollow α-Fe 2 O 3 (hematite) microspheres by the gas-bubble template method. This technique is simple and it does not require hard templates, surfactants, special conditions of atmosphere or complex steps. After reacting Fe(NO 3 ) 3 .9H 2 O and citric acid in water by sol–gel, the precursor was annealed in air at different temperatures between 180 and 600 °C. Annealing at 550 and 600 °C generates bubbles on the melt which crystallize and oxidizes to form hematite hollow spheres after quenching. The morphology and crystal evolution are studied by means of X-ray diffraction and scanning electron microscopy. We found that after annealing at 250–400 °C, the sample consist of a mixture of magnetite, maghemite and hematite. Single hematite phase in the form of hollow microspheres is obtained after annealing at 550 and 600 °C. The crystallization and crystal size of the hematite shells increase with annealing temperature. A possible mechanism for hollow sphere formation is presented. - Highlights: • Formation of hollow hematite microspheres by the gas-bubble template method. • This technique does not require hard templates or special conditions of atmosphere. • Annealing promotes the transition magnetite to maghemite to hematite. • Crystallization of the hematite shells increase with annealing temperature.

  11. Effect of heterogeneity on the characterization of cell membrane compartments: I. Uniform size and permeability.

    Science.gov (United States)

    Hall, Damien

    2010-03-15

    Observations of the motion of individual molecules in the membrane of a number of different cell types have led to the suggestion that the outer membrane of many eukaryotic cells may be effectively partitioned into microdomains. A major cause of this suggested partitioning is believed to be due to the direct/indirect association of the cytosolic face of the cell membrane with the cortical cytoskeleton. Such intimate association is thought to introduce effective hydrodynamic barriers into the membrane that are capable of frustrating molecular Brownian motion over distance scales greater than the average size of the compartment. To date, the standard analytical method for deducing compartment characteristics has relied on observing the random walk behavior of a labeled lipid or protein at various temporal frequencies and different total lengths of time. Simple theoretical arguments suggest that the presence of restrictive barriers imparts a characteristic turnover to a plot of mean squared displacement versus sampling period that can be interpreted to yield the average dimensions of the compartment expressed as the respective side lengths of a rectangle. In the following series of articles, we used computer simulation methods to investigate how well the conventional analytical strategy coped with heterogeneity in size, shape, and barrier permeability of the cell membrane compartments. We also explored questions relating to the necessary extent of sampling required (with regard to both the recorded time of a single trajectory and the number of trajectories included in the measurement bin) for faithful representation of the actual distribution of compartment sizes found using the SPT technique. In the current investigation, we turned our attention to the analytical characterization of diffusion through cell membrane compartments having both a uniform size and permeability. For this ideal case, we found that (i) an optimum sampling time interval existed for the analysis

  12. PLGA/alginate composite microspheres for hydrophilic protein delivery

    International Nuclear Information System (INIS)

    Zhai, Peng; Chen, X.B.; Schreyer, David J.

    2015-01-01

    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

  13. 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.

  14. A facile method for preparing porous, optically active, magnetic Fe3 O4 @poly(N-acryloyl-leucine) inverse core/shell composite microspheres.

    Science.gov (United States)

    Liu, Dong; Deng, Jianping; Yang, Wantai

    2014-01-01

    The first synthesis of porous, optically active, magnetic Fe3 O4 @poly(N-acryloyl-leucine) inverse core/shell composite microspheres is reported, in which the core is constructed of chiral polymer and the shell is constructed of Fe3 O4 NPs. The microspheres integrate three significant concepts, "porosity", "chirality", and "magneticity", in one single microspheric entity. The microspheres consist of Fe3 O4 nanoparticles and porous optically active microspheres, and thus combine the advantages of both magnetic nanoparticles and porous optically active microspheres. The pore size and specific surface area of the microspheres are characterized by N2 adsorption, from which it is found that the composite microspheres possess a desirable porous structure. Circular dichroism and UV-vis absorption spectroscopy measurements demonstrate that the microspheres exhibit the expected optical activity. The microspheres also have high saturation magnetization of 14.7 emu g(-1) and rapid magnetic responsivity. After further optimization, these novel microspheres may potentially find applications in areas such as asymmetric catalysis, chiral adsorption, etc. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Chitosan Microspheres as Radiolabeled Delivery Devices

    International Nuclear Information System (INIS)

    Permtermsin, Chalermsin; Ngamprayad, Tippanan; Phumkhem, Sudkanung; Srinuttrakul, Wannee; Kewsuwan, Prartana

    2007-08-01

    Full text: This study optimized conditions for preparing, characterizing, radiolabeled of chitosan microspheres and the biodistribution of 99mTc-Chitosan microspheres after intravenous administration. Particle size distribution of the microspheres was determined by light scattering. Zeta potential was studied by dynamic light scattering and electrophoresis technique. Biodistribution studies were performed by radiolabeling using 99mTc. The results shown that geometric mean diameter of the microspheres was found to be 77.26?1.96 ?m. Microsphere surface charge of chitosan microspheres was positive charge and zeta potential was 25.80 ? 0.46 mV. The labeling efficiency for this condition was more than 95% and under this condition was stable for at least 6 h. Radioactivity

  16. Biocompatibility of Polyhydroxybutyrate Microspheres: in vitro and in vivo Evaluation

    OpenAIRE

    Shishatskaya, Ekaterina I.; Voinova, Olga N.; Goreva, Anastasya V.; Mogilnaya, Olga A.; Volova, Tatiana G.

    2008-01-01

    Microspheres have been prepared from the resorbable linear polyester of β-hydroxybutyric acid (polyhydroxybutyrate, PHB) by the solvent evaporation technique and investigated in vitro and in vivo. Biocompatibility of the microspheres has been proved in tests in the culture of mouse fibroblast cell line NIH 3Т3 and in experiments on intramuscular implantation of the microspheres to Wistar rats for 3 months. Tissue response to the implantation of polymeric microspheres has been found to consist...

  17. Studies on the recovery of lithium from wash effluent generated during preparation of Li2TiO3 (Lithium Titanate) microspheres for ITER

    International Nuclear Information System (INIS)

    Bamankar, Y.R.; Vittal Rao, T.V.; Pius, I.C.; Mukerjee, S.K.

    2013-01-01

    Methods are being developed for the recovery of lithium from wash effluent generated during the preparation of lithium titanate microspheres which are to be used for breeding tritium in ITER Program. Thermal decomposition of the wash effluent in a furnace at 600°C, resulted in decomposition of the impurities such as ammonium chloride, ammonium nitrate, HMTA, and Urea etc., yielding pure lithium salt. Thermal decomposition of wash effluent containing nitrate was carried out in a controlled manner to avoid explosive decomposition of HMTA and ammonium nitrate. Preliminary investigations were also carried out for the separation of lithium as lithium hydroxide from wash effluent using ion exchange membrane coupled with an electrolytic cell. (author)

  18. Preparation of non-porous microspheres with high entrapment efficiency of proteins by a (water-in-oil)-in-oil emulsion technique.

    Science.gov (United States)

    Viswanathan, N B; Thomas, P A; Pandit, J K; Kulkarni, M G; Mashelkar, R A

    1999-03-08

    Emulsification-solvent removal methods have been widely used for encapsulating bioactive macromolecules like proteins and polypeptides in biodegradable polymers. We report, a (water-in-oil)-in-oil emulsion technique wherein proteins and polypeptides differing in molecular weight and shape were encapsulated in polymers of current biomedical interest. When an oil was used as the processing medium in combination with a carefully selected mixed solvent system such that a stable (w/o1/o2 emulsion is formed and solvents are removed by a combination of extraction and evaporation, the entrapment efficiency was high and the product nonporous. The entrapment efficiency of globular proteins exceeded 90% while that of fibrous proteins was around 70%. Fracture studies revealed that the polymer matrix was dense. The mechanism of entrapment involved solvent-induced precipitation of the protein as the microspheres were being formed. The principle of the method will find use in preparation of non-porous polymer microparticles with reduced burst effect.

  19. Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiajia [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yun; Wang, Jincheng [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Sun, Xiaoli; Cao, Rong [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Sun, Hao [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Department of Chemistry, Liaoning University, Shenyang 110000 (China); Huang, Chaonan [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jiping, E-mail: chenjp@dicp.ac.cn [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China)

    2015-05-04

    Highlights: • BPA imprinted polymer microspheres were prepared by Pickering emulsion polymerization. • Regular spherical shape and narrow diameter distribution. • Good specific adsorption capacity for BPA. • Good class-selectivity and clean-up efficiency for bisphenols in human urine under SPE mode. • Good recoveries and sensitivity for bisphenols using the MIPMS-SPE coupled with HPLC-DAD method. - Abstract: The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption–desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30–60 μm), a specific surface area (S{sub BET}) of 281.26 m{sup 2} g{sup −1} and a total pore volume (V{sub t}) of 0.459 cm{sup 3} g{sup −1}. Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2–2.2 ng mL{sup −1}. The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL{sup −1} for each BP) were in the range of 81.3–106.7% with RSD values below 8.3%.

  20. Preparation of ThO2 sols suitable for gelation into microspheres in CCl4-ammonia media

    International Nuclear Information System (INIS)

    Yamagishi, Shigeru; Takahashi, Yoshihisa

    1985-01-01

    Production conditions of ThO 2 sols are studied for satisfactorily gelling them into microspheres in CCl 4 -ammonia media, which result gel-spheres with good sphericities but need high-quality source-sols for crackfree gelation. Two-stage pH-setting techniques were added to the previously reported method, which had been developed to produce ThO 2 sols suitable for gelation in hexone-ammonia media and was characterized by preneutralization followed by neutralization under pH-control. As a result, colloid fractions of Th in sols were increased without decreasing colloid size. This enabled one to obtain crackfree, large, spherical ThO 2 particles by gelation in the CCl 4 -ammonia media. (author)

  1. Preparación de microesferas mediante secado por aspersión Preparation of microspheres through spray drying

    Directory of Open Access Journals (Sweden)

    Orestes Darío López Hernández

    2008-12-01

    Full Text Available La industria farmacéutica moderna busca constantemente tecnologías para la obtención de transportadores de diferentes fármacos como citostáticos, antiinflamatorios, péptidos y hormonas, entre otros, que impliquen una reducción de su toxicidad y una liberación sostenida o controlada para lograr el efecto terapéutico con una sola dosis. Dentro de estas tecnologías se destaca el empleo de microesferas biodegradables de ácidos polilácticos como sistemas poliméricos matriciales de liberación controlada. En el presente trabajo se exponen aspectos relevantes relacionados con la tecnología de obtención de microesferas mediante secado por aspersión conocido también como Spray drying, el cual tiene como ventajas una alta eficiencia de encapsulación además de ser un método rápido, continuo, relativamente sencillo con respecto a otros existentes, y principalmente brinda la posibilidad de ser escalado hasta nivel de producción.The modern pharmaceutical Industry search constantly technologies for obtaining drugs targeting as antineoplasics, peptides and hormones, among other that imply a toxicity reduction, and sustained or controlled release to achieve the therapeutic effect with a single dose. These technologies employment of biodegradable microspheres of polylactic acids as matricial polymeric systems for controlled release. This work related aspects with the technology of microspheres obtaining by Spray drying which has as advantages, a high encapsulation efficiency, continuous method, relatively simple it offers the possibility of being scale up until production level.

  2. Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples.

    Science.gov (United States)

    Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Cao, Rong; Sun, Hao; Huang, Chaonan; Chen, Jiping

    2015-05-04

    The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption-desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30-60 μm), a specific surface area (S(BET)) of 281.26 m(2) g(-1) and a total pore volume (V(t)) of 0.459 cm(3) g(-1). Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2-2.2 ng mL(-1). The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL(-1) for each BP) were in the range of 81.3-106.7% with RSD values below 8.3%. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Preparation and characterization of ibuprofen-loaded microspheres consisting of poly(3-hydroxybutyrate) and methoxy poly (ethylene glycol)-b-poly (D,L-lactide) blends or poly(3-hydroxybutyrate) and gelatin composites for controlled drug release

    Energy Technology Data Exchange (ETDEWEB)

    Bidone, Juliana; Melo, Ana Paula P. [Laboratorio de Farmacotecnica, Departamento de Ciencias Farmaceuticas, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Bazzo, Giovana C. [Grupo de Estudos em Materiais Polimericos (POLIMAT), Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Carmignan, Francoise [Laboratorio de Farmacotecnica, Departamento de Ciencias Farmaceuticas, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Soldi, Marli S.; Pires, Alfredo T.N. [Grupo de Estudos em Materiais Polimericos (POLIMAT), Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Lemos-Senna, Elenara [Laboratorio de Farmacotecnica, Departamento de Ciencias Farmaceuticas, Universidade Federal de Santa Catarina, Florianopolis (Brazil)], E-mail: lemos@ccs.ufsc.br

    2009-03-01

    Poly-(3-hydroxybutyrate) (P(3HB)) is a biodegradable and biocompatible polymer that has been used to obtain polymer-based drug carriers. However, due to the high crystallinity degree of this polymer, drug release from P(3HB) microspheres frequently occurs at excessive rates. In this study, two strategies for prolonging ibuprofen release from P(3HB)-based microspheres were tested: blending with poly(D,L-lactide)-b-polyethylene glycol (mPEG-PLA); and obtaining composite particles with gelatin (GEL). SEM micrographs showed particles that were spherical and had a rough surface. A slight decrease of the crystallinity degree of P(3HB) was observed only in the DSC thermogram obtained from unloaded-microspheres prepared from 1:1 P(3HB):mPEG-PLA blend. For IBF-loaded microspheres, a reduction of around 10 deg. C in the melting temperature of P(3HB) was observed, indicating that the crystalline structure of the polymer was affected in the presence of the drug. DSC studies also yielded evidence of the presence of a molecular dispersion coexisting with a crystalline dispersion in the drug in the matrix. Similar results were obtained from X-ray diffractograms. In spite of 1:1 mPEG-PLA:P(3HB) blends having contributed to the reduction of the burst effect, a more controlled drug release was provided by the use of the 3:1 P(3HB):mPEGPLA blend. This result indicated that particle hydration played an important role in the drug release. On the other hand, the preparation of P(3HB):GEL composite microspheres did not allow control of the IBF release.

  4. Preparation and characterization of ibuprofen-loaded microspheres consisting of poly(3-hydroxybutyrate) and methoxy poly (ethylene glycol)-b-poly (D,L-lactide) blends or poly(3-hydroxybutyrate) and gelatin composites for controlled drug release

    International Nuclear Information System (INIS)

    Bidone, Juliana; Melo, Ana Paula P.; Bazzo, Giovana C.; Carmignan, Francoise; Soldi, Marli S.; Pires, Alfredo T.N.; Lemos-Senna, Elenara

    2009-01-01

    Poly-(3-hydroxybutyrate) (P(3HB)) is a biodegradable and biocompatible polymer that has been used to obtain polymer-based drug carriers. However, due to the high crystallinity degree of this polymer, drug release from P(3HB) microspheres frequently occurs at excessive rates. In this study, two strategies for prolonging ibuprofen release from P(3HB)-based microspheres were tested: blending with poly(D,L-lactide)-b-polyethylene glycol (mPEG-PLA); and obtaining composite particles with gelatin (GEL). SEM micrographs showed particles that were spherical and had a rough surface. A slight decrease of the crystallinity degree of P(3HB) was observed only in the DSC thermogram obtained from unloaded-microspheres prepared from 1:1 P(3HB):mPEG-PLA blend. For IBF-loaded microspheres, a reduction of around 10 deg. C in the melting temperature of P(3HB) was observed, indicating that the crystalline structure of the polymer was affected in the presence of the drug. DSC studies also yielded evidence of the presence of a molecular dispersion coexisting with a crystalline dispersion in the drug in the matrix. Similar results were obtained from X-ray diffractograms. In spite of 1:1 mPEG-PLA:P(3HB) blends having contributed to the reduction of the burst effect, a more controlled drug release was provided by the use of the 3:1 P(3HB):mPEGPLA blend. This result indicated that particle hydration played an important role in the drug release. On the other hand, the preparation of P(3HB):GEL composite microspheres did not allow control of the IBF release

  5. Microradiographic microsphere manipulator

    International Nuclear Information System (INIS)

    Singleton, R.M.

    1980-01-01

    A method and apparatus are provided for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated to relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres

  6. Uniform molecularly imprinted microspheres and nanoparticles prepared by precipitation polymerization: The control of particle size suitable for different analytical applications

    International Nuclear Information System (INIS)

    Yoshimatsu, Keiichi; Reimhult, Kristina; Krozer, Anatol; Mosbach, Klaus; Sode, Koji; Ye Lei

    2007-01-01

    Molecularly imprinted polymers (MIPs) are being increasingly used as selective adsorbents in different analytical applications. To satisfy the different application purposes, MIPs with well controlled physical forms in different size ranges are highly desirable. For examples, MIP nanoparticles are very suitable to be used to develop binding assays and for microfluidic separations, whereas MIP beads with diameter of 1.5-3 μm can be more appropriate to use in new analytical liquid chromatography systems. Previous studies have demonstrated that imprinted microspheres and nanoparticles can be synthesized using a simple precipitation polymerization method. Despite that the synthetic method is straightforward, the final particle size obtained has been difficult to adjust for a given template. In this work, we initiated to study new synthetic conditions to obtain MIP beads with controllable size in the nano- to micro-meter range, using racemic propranolol as a model template. Varying the composition of the cross-linking monomer allowed the particle size of the MIP beads to be altered in the range of 130 nm to 2.4 μm, whereas the favorable binding property of the imprinted beads remained intact. The chiral recognition sites were further characterized with equilibrium binding analysis using tritium-labeled (S)-propranolol as a tracer. In general, the imprinted sites displayed a high chiral selectivity: the apparent affinity of the (S)-imprinted sites for (S)-propranolol was 20 times that of for (R)-propranolol. Compared to previously reported irregular particles, the chiral selectivity of competitive radioligand binding assays developed from the present imprinted beads has been increased by six to seven folds in an optimized aqueous solvent

  7. Preparation and microwave absorbing property of Ni–Zn ferrite-coated hollow glass microspheres with polythiophene

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lindong; Chen, Xingliang; Qi, Shuhua, E-mail: qishuhuanwpu@163.com

    2016-11-01

    The composite of hollow glass microspheres (HMG) coated by Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} particles was fabricated via sol–gel method, and then the ternary composite (HMG/Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4}/PT) was synthesized by in situ polymerization. The electrical property, magnetic performance and reflection loss of the composites were measured, and the results suggest that the conductivity and the saturation magnetization (Ms) of HMG/Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4}/PT reach 6.87×10{sup −5} S/cm and 11.627 emu/g, respectively. The ternary composite has good microwave absorbing properties (R{sub min}=−13.79 dB at 10.51 GHz) and the bandwidth less than −10 dB can reach 2.6 GHz (from 9.4 to 12.0 GHz) in X band (8.2–12.4 GHz). The morphology and chemical structure of the samples were measured through scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). This paper also analyzes the relationship between the reflection loss of the absorber and its thickness. - Highlights: • This manuscript synthesized HMG/Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4}/PT composites. • The surface morphology, electrical property, magnetic performance and reflection loss of the composites were measured. • This paper also analyzed the relationship between the reflection loss of the absorber and its thickness.

  8. Microspheres prepared with biodegradable PHBV and PLA polymers as prolonged-release system for ibuprofen: in vitro drug release and in vivo evaluation

    Directory of Open Access Journals (Sweden)

    Giovana Carolina Bazzo

    2012-12-01

    Full Text Available In this study, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV and poly(l-lactide (PLA microspheres containing ibuprofen were prepared with the aim of prolonging the drug release. The oil-in-water (O/W emulsion solvent evaporation technique was used, varying the polymer ratio. All formulations provided spherical particles with drug crystals on the surface and a porous and rough polymeric matrix when PHBV was used and smooth external surface when prepared with PLA. The in vitro dissolution profiles show that the formulation containing PHBV/PLA at the proportion of 30/70 presented the best results in terms of prolonging the ibuprofen release. The analysis of the concentration of ibuprofen in the blood of rats showed that maximum levels were achieved at between one and two hours after administration of the immediate-release form (pure drug, while the prolonged microspheres led to a small amount of the drug being released within the first two hours and reached the maximum level after six hours of administration. It was concluded that it is possible to prolong the release of ibuprofen through its incorporation into PHBV/PLA microspheres.No presente estudo foram preparadas microesferas de poli(hidroxibutirato-co-hidroxivalerato (PHBV e poli(ácido láctico (PLA com o objetivo de prolongar a liberação do ibuprofeno, utilizado como fármaco modelo. Empregou-se o método de emulsificação e evaporação do solvente óleo em água (O/A, variando-se a proporção entre os polímeros. Todas as formulações originaram partículas esféricas com cristais de fármaco aderidos à superfície externa. As microesferas apresentaram superfície rugosa e porosa, quando o PHBV foi utilizado, e superfície externa lisa, quando preparadas com o PLA. Os perfis de dissolução in vitro evidenciaram que a formulação que continha PHBV/PLA na proporção de 30/70 apresentou melhores resultados para prolongar a liberação do ibuprofeno. Através da análise da concentra

  9. [Optimization of riboflavin sodium phosphate loading to calcium alginate floating microspheres by response surface methodology].

    Science.gov (United States)

    Zhang, An-yang; Fan, Tian-yuan

    2009-12-18

    To investigate the preparation, optimization and in vitro properties of riboflavin sodium phosphate floating microspheres. The floating microspheres composed of riboflavin sodium phosphate and calcium alginate were prepared using ion gelatin-oven drying method. The properties of the microspheres were investigated, including the buoyancy, release, appearance and entrapment efficiency. The formulation was optimized by response surface methodology (RSM). The optimized microspheres were round. The entrapment efficiency was 57.49%. All the microspheres could float on the artificial gastric juice over 8 hours. The release of the drug from the microspheres complied with Fick's diffusion.

  10. Preparation of Layered-Spinel Microsphere/Reduced Graphene Oxide Cathode Materials for Ultrafast Charge-Discharge Lithium-Ion Batteries.

    Science.gov (United States)

    Luo, Dong; Fang, Shaohua; Yang, Li; Hirano, Shin-Ichi

    2017-12-22

    Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used, the rate capability of LLOs falls short of meeting the requirements of electric vehicles and smart grids. Herein, a layered-spinel microsphere/reduced graphene oxide heterostructured cathode (LS@rGO) is prepared in situ. This cathode is composed of a spinel phase, two layered structures, and a small amount of reduced graphene oxide (1.08 wt % of carbon). The assembly delivers a considerable charge capacity (145 mA h g -1 ) at an ultrahigh charge- discharge rate of 60 C (12 A g -1 ). The rate capability of LS@rGO is influenced by the introduced spinel phase and rGO. X-ray absorption and X-ray photoelectron spectroscopy data indicate that Cr ions move from octahedral lattice sites to tetrahedral lattice sites, and that Mn ions do not participate in the oxidation reaction during the initial charge process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Addition of Zinc Improves the Physical Stability of Insulin in the Primary Emulsification Step of the Poly(lactide-co-glycolide Microsphere Preparation Process

    Directory of Open Access Journals (Sweden)

    Chandrasekar Manoharan

    2015-04-01

    Full Text Available In this study, the effect of zinc on insulin stability during the primary emulsification step of poly(lactide-co-glycolide microspheres preparation by the water-in-oil-in-water (w/o/w double emulsion solvent evaporation technique was evaluated. Insulin was emulsified at homogenization speeds of 5000 and 10,000 rpm. Insulin was extracted from the primary w/o emulsion by a method previously reported from our laboratory and analyzed by comprehensive analytical techniques. The differential scanning calorimetry thermograms of insulin with zinc showed a single peak around 83 °C with calorimetric enthalpy values similar to native insulin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE of extracted insulin showed a single intense band around 6 kDa, demonstrating the preservation of primary structure. High performance liquid chromatography (HPLC analysis revealed that no degradation products were formed during the homogenization process. Insulin aggregates residing at the w/o interfaces were found to be of non-covalent nature. In addition, observation of a single characteristic peak for insulin at m/z 5808 in the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrum confirmed the absence of insulin degradation products and covalent dimers. Presence of zinc preserved the secondary structure of insulin as indicated by circular dichroism. In conclusion, these results show that with the addition of zinc, insulin stability can be improved during the primary emulsification step.

  12. Development and evaluation of floating microspheres of curcumin in ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence and to study their effect on alloxan-induced diabetic rats. Methods: Floating microsphere were prepared by emulsion-solvent diffusion method, using hydroxylpropyl methylcellulose, chitosan and Eudragit S 100 polymer in ...

  13. Development and Evaluation of Floating Microspheres of Curcumin ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence time and increased drug bioavailability. Methods: Floating microsphere were prepared by emulsion solvent diffusion method, using hydroxylpropyl methylcellulose (HPMC), ethyl cellulose (EC), Eudragit S 100 polymer in ...

  14. 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.

  15. Preparation of titanium oxide and metal titanates as powders, thin films, and microspheres by complex sol-gel process

    International Nuclear Information System (INIS)

    Deptula, A.; Olczak, T.; Lada, W.; Chmielewski, A.G.; Jakubaszek, U.; Sartowska, B.; Goretta, K.C.; Alvani, C.; Casadio, S.; Contini, V.

    2006-01-01

    Titanium oxide, for many years an important pigment, has recently been applied widely as a photocatalyst or as supports for metallic catalysts, gas sensors, photovoltaic solar cells, and water and air purification devices. Titanium oxide (TiO 2 ) and titanates based on Ba, Sr and Ca were prepared from commercial solutions of TiCl 4 and HNO 3 . The main preparation steps for the sols consisted of elimination of Cl - by distillation with HNO 3 and addition of metal hydroxides for the titanates. Resulting sols were gelled and used to: (a) prepare irregularly shaped powders by evaporation; (b) produce by a dipping technique thin films on glass, Ag or Ti supports; (c) produce spherical powders (diameters <100 μm) by solvent extraction. Results of thermal and X-ray-diffraction analyses indicated that the temperatures required to form the various compounds were lower than those necessary to form the compounds by conventional solid-state reactions and comparable to those required with use of organometallic based sol-gel methods. Temperatures of formation could be further reduced by addition of ascorbic acid (ASC) to the sols

  16. General Approach to Prepare 0.33Li₂MnO₃ · 0.67LiNi1/3Co1/3Mn1/3O₂ Hollow Microspheres for High Performance Lithium Ion Batteries.

    Science.gov (United States)

    Li, Jingfa; Xu, Wenjin; Zhang, Lei; Li, Min

    2018-06-01

    Li-excess manganese-based oxide layered structures, have drawn increasing interests as the promising cathodes to succeed the conventional LiCoO2 in lithium ion batteries (LIBs). It could deliver a higher energy density and output potential, as well as the nature of environment benign and low cost. Pristine Li-excess manganese-based oxides however suffer from poor rate capacity and voltage fading after cycling, and their inherent capacity limits of bulk size in performance. Micro-/Nanostructured electrode materials are considered to hold the key to overcome these thresholds. This paper reports a general approach to prepare 0.33Li2MnO3 · 0.67LiNi1/3Co1/3Mn1/3O2 microspheres with pores and void space, which benefits improving both the capacity and cyclability. The electrode made of hollow 0.33Li2MnO3 · 0.67LiNi1/3Co1/3Mn1/3O2 microspheres exhibits a 224 mAh g-1 discharge capacity over 200 cycles at 0.25 C rate, and 195 mAh g-1 at 5.0 C rate. These results indicated good perspective of hollow microspheres for practical battery applications.

  17. Microsphere based improved sunscreen formulation of ethylhexyl methoxycinnamate.

    Science.gov (United States)

    Gogna, Deepak; Jain, Sunil K; Yadav, Awesh K; Agrawal, G P

    2007-04-01

    Polymethylmethacrylate (PMMA) microspheres of ethylhexyl methoxycinnamate (EHM) were prepared by emulsion solvent evaporation method to improve its photostability and effectiveness as sunscreening agent. Process parameters like stirring speed and aqueous polyvinyl alcohol (PVA) concentration were analyzed in order to optimize the formulations. Shape and surface morphology of the microspheres were examined using scanning electron microscopy. Particle size of the microspheres was determined using laser diffraction particle size analyzer. The PMMA microspheres of EHM were incorporated in water-removable cream base. The in vitro drug release of EHM in pH 7.4 was performed using dialysis membrane. Thin layer chromatography was performed to determine photostability of EHM inside the microspheres. The formulations were evaluated for sun protection factor (SPF) and minimum erythema dose (MED) in albino rats. Cream base formulation containing microspheres prepared using EHM:PMMA in ratio of 1:3 (C(3)) showed slowest drug (EHM) release and those prepared with EHM: PMMA in ratio of 1:1 showed fastest release. The cream base formulations containing EHM loaded microspheres had shown better SPF (more than 16.0) as compared to formulation C(d) that contained 3% free EHM as sunscreen agent and showed SPF 4.66. These studies revealed that the incorporation of EHM loaded PMMA microspheres into cream base had greatly increased the efficacy of sunscreen formulation approximately four times. Further, photostability was also shown to be improved in PMMA microspheres.

  18. HTGR Fuel Recycle Development Program (189a OHO45). Fuel refabrication, Task 500. Rate-controlling factors in the carbothermic preparation of UO2--UC2--C microspheres

    International Nuclear Information System (INIS)

    Stinton, D.P.; Tiegs, S.M.; Lackey, W.J.; Lindemer, T.B.

    1979-01-01

    Rate controlling factors in the conversion of UO 2 + C microspheres to UC 2 + C were investigated using a 13-cm-dia fluidized bed furnace. X-ray diffraction, ion microprobe, and microstructural examination revealed that the conversion of UO 2 to UC 2 began at the surface of the microsphere and progressed toward the central unreacted core. Kinetic models for solid state reactions in spheres were evaluated by using quantitative mass spectrometric data on the rae of evolution of carbon monoxide during conversion. This analysis revealed that the rate of conversion was controlled by reaction at the outer surface of the microsphere. Also, decreased partial pressures of carbon monoxide were found to accelerate the rate of reaction

  19. Preparation methods for monodispersed garlic oil microspheres in water using the microemulsion technique and their potential as antimicrobials.

    Science.gov (United States)

    Zheng, Hua Ming; Li, Hou Bin; Wang, Da Wei; Liu, Dun

    2013-08-01

    Garlic oil is considered as a natural broad-spectrum antibiotic because of its well-known antimicrobial activity. However, the characteristics of easy volatility and poor aqueous solubility limit the application of garlic oil in industry. The purpose of the present work is to develop and evaluate an oil-free microemulsion by loading garlic oil in microemulsion system. Microemulsions were prepared with ethoxylated hydrogenated castor (Cremophor RH40) as surfactant, n-butanol (or ethanol) as cosurfactant, oleic acid-containing garlic oil as oil phase, and ultrapure water as water phase. The effects of the ratio of surfactant to cosurfactant and different oil concentration on the area of oil-in-water (O/W) microemulsion region in pseudoternary phase diagrams were investigated. The particle size and garlic oil encapsulation efficiency of the formed microemulsions with different formulations were also investigated. In addition, the antimicrobial activity in vitro against Escherichia coli and Staphylococcus aureus was assessed. The experimental results show that a stable microemulsion region can be obtained when the mass ratio of surfactant to cosurfactant is, respectively, 1:1, 2:1, and 3:1. Especially, when the mixture surfactants of RH40/n-butanol 2/1 (w/w) is used in the microemulsion formulation, the area of O/W microemulsion region is 0.089 with the particle size 13.29 to 13.85 nm and garlic oil encapsulation efficiency 99.5%. The prepared microemulsion solution exhibits remarkable antibacterial activity against S. aureus. © 2013 Institute of Food Technologists®

  20. Preparation of magnetic core mesoporous shell microspheres with C18-modified interior pore-walls for fast extraction and analysis of phthalates in water samples.

    Science.gov (United States)

    Li, Zhongbo; Huang, Danni; Fu, Chinfai; Wei, Biwen; Yu, Wenjia; Deng, Chunhui; Zhang, Xiangmin

    2011-09-16

    In this study, core-shell magnetic mesoporous microspheres with C18-functionalized interior pore-walls were synthesized through coating Fe(3)O(4) microspheres with a mesoporous inorganic-organic hybrid layer with a n-octadecyltriethoxysilane (C18TES) and tetraethyl orthosilicate (TEOS) as the silica source and cetyltrimethylammonia bromide (CTAB) as a template. The obtained C18-functionalized Fe(3)O(4)@mSiO(2) microspheres possess numerous C18 groups anchored in the interior pore-walls, large surface area (274.7 m(2)/g, high magnetization (40.8 emu/g) and superparamagnetism, uniform mesopores (4.1 nm), which makes them ideal absorbents for simple, fast, and efficient extraction and enrichment of hydrophobic organic compounds in water samples. Several kinds of phthalates were used as the model hydrophobic organic compounds to systematically evaluate the performance of the C18-functionalized Fe(3)O(4)@mSiO(2) microspheres in extracting hydrophobic molecules by using a gas chromatography-mass spectrometry. Various parameters, including eluting solvent, the amounts of absorbents, extraction time and elution time were optimized. Hydrophobic extraction was performed in the interior pore of magnetic mesoporous microspheres, and the materials had the anti-interference ability to macromolecular proteins, which was also investigated in the work. Under the optimized conditions, C18-functionalized Fe(3)O(4)@mSiO(2) microspheres were successfully used to analyze the real water samples. The results indicated that this novel method was fast, convenient and efficient for the target compounds and could avoid being interfered by macromolecules. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Ag/α-Fe{sub 2}O{sub 3} hollow microspheres: Preparation and application for hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Xinyuan; Wu, Zhiping; Liao, Fang, E-mail: liaozhang2003@163.com; Zhang, Tingting; Guo, Tingting

    2015-09-15

    In this paper, we demonstrated a simple approach for preparing α-Fe{sub 2}O{sub 3} hollow spheres by mixing ferric nitrate aqueous and glucose in 180 °C. The glucose was found to act as a soft template in the process of α-Fe{sub 2}O{sub 3} hollow spheres formation. Ag/α-Fe{sub 2}O{sub 3} hollow nanocomposite was obtained under UV irradiation without additional reducing agents or initiators. Synthesized Ag/α-Fe{sub 2}O{sub 3} hollow composites exhibited remarkable catalytic performance toward H{sub 2}O{sub 2} reduction. The electrocatalytic activity mechanism of Ag/α-Fe{sub 2}O{sub 3}/GCE were discussed toward the reduction of H{sub 2}O{sub 2} in this paper. - Graphical abstract: Glucose is carbonized as carbon balls in the 180 °C hydrothermal carbonization process, which plays a role of a soft template. Carbon spherical shell is rich in many hydroxyls, which have good hydrophilicity and surface reactivity. When Fe(NO{sub 3}){sub 3} is added to the aqueous solution of Glucose, the hydrophilic -OH will adsorb Fe{sup 3+} to form coordination compound by coordination bond. α-FeOOH is formed on the surface of carbon balls by hydrothermal reaction. After calcination at 500 °C, carbon spheres react with oxygen to form carbon dioxide, which disappears in the air. Meanwhile α-FeOOH is calcined to form α-Fe{sub 2}O{sub 3} hollow spheres.

  2. Microspheres Prepared by Internal Gelation for Actinide Co-Conversion - Influence of Organic Precursors in Initial Solution on Structure during Thermal Treatment

    International Nuclear Information System (INIS)

    Benay, G.; Modolo, G.; Robisson, A.C.; Grandjean, S.

    2008-01-01

    The fabrication of fuels or targets for transmutation of minor actinides requires a dust-free process. Such a requirement can be fulfilled by sol-gel methods, which allow the production of microsphere precursors. Internal gelation, one of these methods, was studied at Cea Marcoule and FZ (Forschungszentrum Juelich Germany). A study of the parameters involved in internal gelation (essentially the quantity of organic additives urea and hexa-methylene-tetramine (HMTA) present in the initial solution) was performed. Afterwards, the effects of these parameters on the structural evolution of the microspheres during thermal treatment were studied. It was observed that the structure and density of the microspheres are heavily dependant of the quantity of organic precursors present in the initial solution. Urea in particular has been found to bring porosity to the material, in addition to its catalytic effect on HMTA decomposition. The elimination of these organic compounds is however a major issue which causes the formation of cracks on the microspheres if no optimization is performed. (authors)

  3. 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.

  4. Factors influencing formation of highly dispersed BaTiO3 nanospheres with uniform sizes in static hydrothermal synthesis

    International Nuclear Information System (INIS)

    Gao, Jiabing; Shi, Haiyue; Dong, Huina; Zhang, Rui; Chen, Deliang

    2015-01-01

    Highly dispersed BaTiO 3 nanospheres with uniform sizes have important applications in micro/nanoscale functional devices. To achieve well-dispersed spherical BaTiO 3 nanocrystals, we carried out as reported in this paper the systematic investigation on the factors that influence the formation of BaTiO 3 nanospheres by the static hydrothermal process, including the NaOH concentrations [NaOH], molar Ba/Ti ratios (R Ba/Ti ), hydrothermal temperatures, and durations, with an emphasis on understanding the related mechanisms. Barium nitrate and TiO 2 sols derived from tetrabutyl titanate were used as the starting materials. The as-synthesized BaTiO 3 samples were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetry, differential thermal analysis, and FT-IR spectra. The highly dispersed BaTiO 3 nanospheres (76 ± 13 nm) were achieved under the optimum hydrothermal conditions at 200 °C for 10 h: [NaOH] = 2.0 mol L −1 and R Ba/Ti  = 1.5. Higher NaOH concentrations, higher Ba/Ti ratios, higher hydrothermal temperatures, and longer hydrothermal durations are favorable in forming BaTiO 3 nanospheres with larger fractions of tetragonal phase and higher yields; but too long hydrothermal durations resulted in abnormal growth and reduced the uniformity in particle sizes. The possible formation mechanisms for BaTiO 3 nanocrystals under the static hydrothermal conditions were investigated

  5. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Meyer, S.F.

    1980-01-01

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  6. Preparation of surface modified TiO2/rGO microspheres and application in the photocatalytic decomposition of oleic acid

    Science.gov (United States)

    Wu, Xin; Zeng, Min; Tong, Xiaoling; Li, Fuyun; Xu, Youyou

    2018-05-01

    The comprehensive utilization of waste cooking oil is an important research topic in food science. In this study, the surface modified mesoporous anatase TiO2/reduced graphene oxide (rGO) microspheres with a high specific surface area have been successfully synthesized, through hydrothermal routes and hydrazine reduced graphene oxide. The photocatalytic decomposition of waste rapeseed oil has also been studied using TiO2/rGO microspheres as photocatalyst. The result shows that the reduced graphene oxide in these nanocomposites can act as adsorbent and photocatalyst, and the temperature and the oxygen amount also are the most important factors affecting the oleic acid decomposition products. There interesting results not only helpful for the study of the mechanism of photocatalytic, but also useful for the rational use of waste cooking oil.

  7. 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). Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 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.

  9. Preparation and crystallization of hollow α-Fe{sub 2}O{sub 3} microspheres following the gas-bubble template method

    Energy Technology Data Exchange (ETDEWEB)

    Valladares, L. de los Santos, E-mail: ld301@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J Thomson Av., Cambridge, CB3 0HE (United Kingdom); León Félix, L. [Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Laboratory of Magnetic Characterization, Instituto de Física, Universidade de Brasília, DF 70910-900, Brasilia (Brazil); Espinoza Suarez, S.M.; Bustamante Dominguez, A.G. [Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Mitrelias, T.; Holmes, S. [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J Thomson Av., Cambridge, CB3 0HE (United Kingdom); Moreno, N.O. [Departamento de Física, Universidade Federal de Sergipe, 49100-000, Sao Cristóvao, Sergipe (Brazil); Albino Aguiar, J. [Laboratório de Supercondutividade e Materiais Avançados, Departamento de Física, Universidade Federal de Pernambuco, 50670-901, Recife (Brazil); Barnes, C.H.W. [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J Thomson Av., Cambridge, CB3 0HE (United Kingdom)

    2016-02-01

    In this work we report the formation of hollow α-Fe{sub 2}O{sub 3} (hematite) microspheres by the gas-bubble template method. This technique is simple and it does not require hard templates, surfactants, special conditions of atmosphere or complex steps. After reacting Fe(NO{sub 3}){sub 3}.9H{sub 2}O and citric acid in water by sol–gel, the precursor was annealed in air at different temperatures between 180 and 600 °C. Annealing at 550 and 600 °C generates bubbles on the melt which crystallize and oxidizes to form hematite hollow spheres after quenching. The morphology and crystal evolution are studied by means of X-ray diffraction and scanning electron microscopy. We found that after annealing at 250–400 °C, the sample consist of a mixture of magnetite, maghemite and hematite. Single hematite phase in the form of hollow microspheres is obtained after annealing at 550 and 600 °C. The crystallization and crystal size of the hematite shells increase with annealing temperature. A possible mechanism for hollow sphere formation is presented. - Highlights: • Formation of hollow hematite microspheres by the gas-bubble template method. • This technique does not require hard templates or special conditions of atmosphere. • Annealing promotes the transition magnetite to maghemite to hematite. • Crystallization of the hematite shells increase with annealing temperature.

  10. 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

  11. Temperature influence in crystallinity of polymer microspheres; Influencia da temperatura na cristalinidade de microesferas polimericas

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Cristiane de P.; Novack, Katia M., E-mail: knovack@iceb.ufop.br [Universidade Federal de Ouro Preto - UFOP, ICEB, DEQUI, Ouro Preto, MG (Brazil)

    2011-07-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  12. 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...... 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....

  13. Antibacterial activity of ciprofloxacin-loaded zein microsphere films

    International Nuclear Information System (INIS)

    Fu Jianxi; Wang Huajie; Zhou Yanqing; Wang Jinye

    2009-01-01

    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 μm. 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.

  14. 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.

  15. Effects of Temperature and pH on Immobilized Laccase Activity in Conjugated Methacrylate-Acrylate Microspheres

    Directory of Open Access Journals (Sweden)

    Siti Zulaikha Mazlan

    2017-01-01

    Full Text Available Immobilization of laccase on the functionalized methacrylate-acrylate copolymer microspheres was studied. Poly(glycidyl methacrylate-co-n-butyl acrylate microspheres consisting of epoxy groups were synthesized using facile emulsion photocuring technique. The epoxy groups in poly(GMA-co-nBA microspheres were then converted to amino groups. Laccase immobilization is based on covalent binding via amino groups on the enzyme surface and aldehyde group on the microspheres. The FTIR spectra showed peak at 1646 cm−1 assigned to the conformation of the polymerization that referred to GMA and nBA monomers, respectively. After modification of the polymer, intensity of FTIR peaks assigned to the epoxy ring at 844 cm−1 and 904 cm−1 was decreased. The results obtained from FTIR exhibit a good agreement with the epoxy content method. The activity of laccase-immobilized microspheres increased upon increasing the epoxy content. Furthermore, poly(GMA-co-nBA microspheres revealed uniform size below 2 µm that contributes to large surface area of the microspheres to be used as a matrix, thus increasing the enzyme capacity and enzymatic reaction. Immobilized enzyme also shifted to higher pH and temperature compared to free enzyme.

  16. Novel ionically crosslinked acrylamide-grafted poly(vinyl alcohol)/sodium alginate/sodium carboxymethyl cellulose pH-sensitive microspheres for delivery of Alzheimer's drug donepezil hydrochloride: Preparation and optimization of release conditions.

    Science.gov (United States)

    Bulut, Emine; Şanlı, Oya

    2016-01-01

    In this work, the graft copolymer, poly(vinyl alcohol)-grafted polyacrylamide (PVA-g-PAAm), was synthesized and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. Microspheres of PVA-g-PAAm/sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) were prepared by the emulsion-crosslinking method and used for the delivery of an Alzheimer's drug, donepezil hydrochloride (DP). The release of DP increased with the increase in drug/polymer ratio (d/p) and PVA-g-PAAm/NaAlg/NaCMC ratio, while it decreased with the increase in the extent of crosslinking. The optimum DP release was obtained as 92.9% for a PVA-g-PAAm/NaAlg/NaCMC ratio of 1/2/1, d/p ratio of 1/8, and FeCl3 concentration of 7% (w/v).

  17. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    International Nuclear Information System (INIS)

    Hu, Xixue; Shen, Hong; Yang, Fei; Liang, Xinjie; Wang, Shenguo; Wu, Decheng

    2014-01-01

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion–solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  18. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xixue [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190 (China); Shen, Hong, E-mail: shenhong516@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Fei [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liang, Xinjie [CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190 (China); Wang, Shenguo, E-mail: wangsg@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Decheng, E-mail: dcwu@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-02-15

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion–solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  19. Research progress of fabricating polyvinyl alcohol coating on plastic microsphere

    International Nuclear Information System (INIS)

    Su Lin; Chen Sufen; Liu Meifang; Zhang Zhanwen; Yao Hong; Li Bo; Liu Yiyang

    2012-01-01

    In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 μm, with high survival ratio and good quality. However, the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing the droplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 μm, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform. (authors)

  20. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author) [es

  1. Polymer based microspheres of aceclofenac as sustained release parenterals for prolonged anti-inflammatory effect

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet; Sharma, Sumit; Sinha, VR, E-mail: sinha_vr@rediffmail.com

    2017-03-01

    Poly(lactic-co-glycolic acid) (PLGA) (75:25) and polycaprolactone (PCL) microspheres were fabricated for prolonged release of aceclofenac by parenteral administration. Microspheres encapsulating aceclofenac were designed to release the drug at controlled rate for around one month. Biodegradable microspheres were prepared by solvent emulsification evaporation method in different polymer:drug ratios (1:1, 2:1 and 3:1). After drug loading, PLGA and PCL microspheres showed a controlled size distribution with an average size of 11.75 μm and 3.81 μm respectively and entrapment efficiency in the range of 90 ± 0.72% to 91.06 ± 4.01% with PLGA and 83.01 ± 2.13% to 90.4 ± 2.11% with PCL. Scanning electron microscopy has confirmed good spherical structures of microspheres. The percent yield of biodegradable polymeric microspheres ranged between 30.95 ± 10.14% to 92.84 ± 3.15% and 47.33 ± 4.72% to 80 ± 3.60% for PLGA and PCL microspheres respectively. PLGA microspheres followed Higuchi release pattern while Korsmeyer-Peppas explained the release pattern of PCL microspheres. Stability studies of microspheres were also carried out by storing the preparations at 2-8 °C for 30, 60 and 90 days and evaluating them for entrapment efficiency, residual drug content and polymer drug compatability. In-vivo studies showed significant anti-inflammatory activity of microspheres upto 48 hours using the carrageenan induced rat paw oedema model. - Highlights: • PLGA and PCL polymeric microspheres for parenteral prolonged drug delivery system were formulated. • Polymeric microspheres were characterized physically and drug excipient incompatability. • Three months accelerated stability studies were carried for drug loaded polymeric microspheres. • Pharmacodynamic studies prove the rationality of sustained therapeutic effect of designed drug delivery system.

  2. Method for sizing hollow microspheres

    Science.gov (United States)

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  3. Synthesis and characterization of Supeparamagnetics Microspheres (PMMA via suspension polymerization

    Directory of Open Access Journals (Sweden)

    Paulo Emilio Feuser

    2014-02-01

    Full Text Available Magnetics nanoparticles (NPMs has found many applications in biomedical and technological areas. The objective of this work is the preparation and characterization of PMMA microspheres containing NPMs coated with oleic acid (NPMs-AO. For the preparation of MNPs-AO was used the coprecipitation method in an aqueous medium. For the preparation of the superparamagnetic microspheres used in suspension polymerization technique. The microspheres showed a size distribution particles of approximately 150um and a spherical morphology. From the analysis of gel permeation chromatography (GPC determined the number average molecular weight (Mw of the magnetics microspheres and there was a variation in the Mw depending on the concentration of MNPs-AO in this reaction. To analyze the magnetic properties used the vibrating sample magnetometer (MAV. The microspheres showed superparamagnetic properties and a value of saturation magnetization (Ms of about 8 emu/g MNPs. Therefore you can conclude that it is possible to obtain superparamagnetics microspheres for a particular application, either, biomedical or technological.

  4. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2011-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  5. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2010-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  6. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2012-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  7. 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.

  8. Magnetic poly(glycidyl methacrylate) microspheres for protein capture.

    Science.gov (United States)

    Koubková, Jana; Müller, Petr; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, Bořivoj; Horák, Daniel

    2014-09-25

    The efficient isolation and concentration of protein antigens from complex biological samples is a critical step in several analytical methods, such as mass spectrometry, flow cytometry and immunochemistry. These techniques take advantage of magnetic microspheres as immunosorbents. The focus of this study was on the development of new superparamagnetic polymer microspheres for the specific isolation of the tumor suppressor protein p53. Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres measuring approximately 5 μm and containing carboxyl groups were prepared by multistep swelling polymerization of glycidyl methacrylate (GMA), 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) and ethylene dimethylacrylate (EDMA) as a crosslinker in the presence of cyclohexyl acetate as a porogen. To render the microspheres magnetic, iron oxide was precipitated within their pores; the Fe content in the particles received ∼18 wt%. Nonspecific interactions between the magnetic particles and biological media were minimized by coating the microspheres with poly(ethylene glycol) (PEG) terminated by carboxyl groups. The carboxyl groups of the magnetic PGMA microspheres were conjugated with primary amino groups of mouse monoclonal DO-1 antibody using conventional carbodiimide chemistry. The efficiency of protein p53 capture and the degree of nonspecific adsorption on neat and PEG-coated magnetic microspheres were determined by western blot analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Current knowledge on biodegradable microspheres in drug delivery.

    Science.gov (United States)

    Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

    2015-08-01

    Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.

  10. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao; Xiao, Manda; Bao, Zhihong; Wang, Peng; Wang, Jianfang

    2012-01-01

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao

    2012-04-26

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of various polymers concentrations on physicochemical properties of floating microspheres.

    Science.gov (United States)

    Jagtap, Y M; Bhujbal, R K; Ranade, A N; Ranpise, N S

    2012-11-01

    Floating microspheres have emerged as a potential candidate for gastroretentive drug delivery system. For developing a desired intragastric floatation system employing these microspheres, it is necessary to select an appropriate balance between buoyancy and drug releasing rate. These properties mainly depend on the polymers used in the formulation of the microspheres. Hence it is necessory to study the effect of these polymer concentrations on the various physicochemical properties of the microspheres. Floating microspheres were prepared by emulsion solvent evaporation technique utilising different polymers such as ethyl cellulose, Eudragit(®) RS and Eudragit(®) RL by dissolving them in a mixture of dichloromethane and methanol. Release modifiers studied were hydroxypropyl methylcellulose K4M, hydroxypropyl methylcellulose E50 LV and Eudragit(®) EPO. Prepared microspheres were analysed for particle size, surface morphology, entrapment efficiency, buoyancy, differential scanning calorimetry and in-vitro drug release. Ethyl cellulose and Eudragit(®) EPO resulted microspheres with high percentage yield, excellent spherical shape but had very less buoyancies with a high cumulative drug release. Ethyl cellulose microspheres prepared using hydroxypropyl methylcellulose K4M showed more sustained drug release and high buoyancies than that of the microspheres formulated with the hydroxypropyl methylcellulose E50 LV. Amongst these hydroxypropyl methylcellulose E50 LV showed good balance between buoyancy and the drug release.

  13. Layer-by-Layer Motif Architectures: Programmed Electrochemical Syntheses of Multilayer Mesoporous Metallic Films with Uniformly Sized Pores.

    Science.gov (United States)

    Jiang, Bo; Li, Cuiling; Qian, Huayu; Hossain, Md Shahriar A; Malgras, Victor; Yamauchi, Yusuke

    2017-06-26

    Although multilayer films have been extensively reported, most compositions have been limited to non-catalytically active materials (e.g. polymers, proteins, lipids, or nucleic acids). Herein, we report the preparation of binder-free multilayer metallic mesoporous films with sufficient accessibility for high electrocatalytic activity by using a programmed electrochemical strategy. By precisely tuning the deposition potential and duration, multilayer mesoporous architectures consisting of alternating mesoporous Pd layers and mesoporous PdPt layers with controlled layer thicknesses can be synthesized within a single electrolyte, containing polymeric micelles as soft templates. This novel architecture, combining the advantages of bimetallic alloys, multilayer architectures, and mesoporous structures, exhibits high electrocatalytic activity for both the methanol oxidation reaction (MOR) and the ethanol oxidation reaction (EOR). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de

    2011-01-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho 2 O 3 . Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  15. Microspheres of poly({epsilon}-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho{sub 2}O{sub 3}. Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  16. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  17. 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.

  18. Uniformly sized gold nanoparticles derived from PS-b-P2VP block copolymer templates for the controllable synthesis of Si nanowires.

    Science.gov (United States)

    Lu, Jennifer Q; Yi, Sung Soo

    2006-04-25

    A monolayer of gold-containing surface micelles has been produced by spin-coating solution micelles formed by the self-assembly of the gold-modified polystyrene-b-poly(2-vinylpyridine) block copolymer in toluene. After oxygen plasma removed the block copolymer template, highly ordered and uniformly sized nanoparticles have been generated. Unlike other published methods that require reduction treatments to form gold nanoparticles in the zero-valent state, these as-synthesized nanoparticles are in form of metallic gold. These gold nanoparticles have been demonstrated to be an excellent catalyst system for growing small-diameter silicon nanowires. The uniformly sized gold nanoparticles have promoted the controllable synthesis of silicon nanowires with a narrow diameter distribution. Because of the ability to form a monolayer of surface micelles with a high degree of order, evenly distributed gold nanoparticles have been produced on a surface. As a result, uniformly distributed, high-density silicon nanowires have been generated. The process described herein is fully compatible with existing semiconductor processing techniques and can be readily integrated into device fabrication.

  19. Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

    Directory of Open Access Journals (Sweden)

    Narinder Singh

    Full Text Available Aim: Current experimental investigation is dedicated to prepare microspheres with small size and good sphericity by Phase Separation method using Isoniazid (INH as model drug. Silk fibroin has unique intrinsic qualities like biodegradability, biocompatibility or release properties and their tunable drug loading capacity. The delivery loading proficiency of the drug molecules in silk spheres be contingent on their charge, and hydrophobicity or subsequent in altered drug release profiles. Methods: In the present work Isoniazid loaded silk fibroin microsphere was prepared by using phase separation method. Microsphere was evaluated for Ultraviolet-visible spectroscopy, Fourier Transform infrared spectroscopy, Entrapment efficiency, Scanning electron microscopy Studies. Results: Scanning electron microscopy studies revealed that Isoniazid Loaded Silk Fibroin Microspheres were spherical. Entrapment Efficiency of Isoniazid loaded Microspheres of different Formulation from F1 to F5 was in range of 53 to 68 %. F3 showed 68.47 % entrapment Efficiency and the optimized formulation drug release was 93.56 % at 24 hours. Conclusion: Experimental report disclosed a new aqueous based formulation method for silk spheres with controllable shape or size and sphere. Isoniazid loaded silk microspheres may act as ideal nano formulation with elaborated studies.

  20. Pr6O11 micro-spherical nano-assemblies: Microwave-assisted synthesis, characterization and optical properties

    International Nuclear Information System (INIS)

    Majeed, Shafquat; Shivashankar, S.A.

    2013-01-01

    We report the synthesis of Pr 6 O 11 microspheres self-assembled from ultra-small nanocrystals formed by the microwave irradiation of a solution of a salt of Pr in ethylene glycol (EG). The as-prepared product consists of microspheres measuring 200 to 500 nm in diameter and made of 6 O 11 microspheres assembled from ultra-small nanocrystals were synthesized. • As-prepared microspheres are covered by ethylene glycol as shown by IR analysis. • Role of temperature and pressure on self-assembly studied. • Luminescence emission behaviour of as-prepared and annealed products studied

  1. Development and optimization of enteric coated mucoadhesive microspheres of duloxetine hydrochloride using 3(2) full factorial design.

    Science.gov (United States)

    Setia, Anupama; Kansal, Sahil; Goyal, Naveen

    2013-07-01

    Microspheres constitute an important part of oral drug delivery system by virtue of their small size and efficient carrier capacity. However, the success of these microspheres is limited due to their short residence time at the site of absorption. The objective of the present study was to formulate and systematically evaluate in vitro performance of enteric coated mucoadhesive microspheres of duloxetine hydrochloride (DLX), an acid labile drug. DLX microspheres were prepared by simple emulsification phase separation technique using chitosan as carrier and glutaraldehyde as a cross-linking agent. Microspheres prepared were coated with eudragit L-100 using an oil-in-oil solvent evaporation method. Eudragit L-100was used as enteric coating polymer with the aim to release the drug in small intestine The microspheres prepared were characterized by particle size, entrapment efficiency, swelling index (SI), mucoadhesion time, in vitro drug release and surface morphology. A 3(2) full factorial design was employed to study the effect of independent variables polymer-to-drug ratio (X1) and stirring speed (X2) on dependent variables, particle size, entrapment efficiency, SI, in vitro mucoadhesion and drug release up to 24 h (t24). Microspheres formed were discrete, spherical and free flowing. The microspheres exhibited good mucoadhesive property and also showed high percentage entrapment efficiency. The microspheres were able to sustain the drug release up to 24 h. Thus, the prepared enteric coated mucoadhesive microspheres may prove to be a potential controlled release formulation of DLX for oral administration.

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

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming; Wang Zhifeng; Zhang Hong; Dai Shaojun; Qiu Guanming; Okamoto Hiroshi

    2005-01-01

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

  3. INVESTIGATION OF DRUG RELEASE FROM BIODEGRADABLE PLG MICROSPHERES: EXPERIMENT AND THEORY

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS, MALCOLM J. [Los Alamos National Laboratory; BERCHANE, NADER S. [Los Alamos National Laboratory; CARSON, KENNETH H. [Los Alamos National Laboratory; RICE-FICHT, ALLISON C. [Los Alamos National Laboratory

    2007-01-30

    Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

  4. Characterization of unsaturated fatty acid sustained-release microspheres for long-term algal inhibition.

    Science.gov (United States)

    Ni, Lixiao; Jie, Xiaoting; Wang, Peifang; Li, Shiyin; Hu, Shuzhen; Li, Yiping; Li, Yong; Acharya, Kumud

    2015-02-01

    The unsaturated fatty acid (linoleic acid) sustained-release microspheres were prepared with linoleic acid (LA) using alginate-chitosan microcapsule technology. These LA sustained-release microspheres had a high encapsulation efficiency (up to 62%) tested by high performance liquid chromatography with a photo diode array. The dry microspheres were characterized by a scanning electron microscope, X-ray diffraction measurement, dynamic thermogravimetric analysis and Fourier transform infrared spectral analysis. The results of characterization showed that the microspheres had good thermal stability (decomposition temperature of 236°C), stable and temperature independent release properties (release time of more than 40 d). Compared to direct dosing of LA, LA sustained-released microspheres could inhibit Microcystis aeruginosa growth to the non-growth state. The results of this study suggested that the LA sustained-release microspheres may be a potential candidate for algal inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Release of proteins via ion exchange from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, H.F.M.; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Albumin-heparin and albumin microspheres were prepared as ion exchange gels for the controlled release of positively charged polypeptides and proteins. The adsorption isotherms of chicken egg and human lysozyme, as model proteins, on microspheres were obtained. An adsorption isotherm of chicken egg

  6. Formulation, evaluation and 3(2) full factorial design-based optimization of ondansetron hydrochloride incorporated taste masked microspheres.

    Science.gov (United States)

    Kharb, Vandana; Saharan, Vikas Anand; Dev, Kapil; Jadhav, Hemant; Purohit, Suresh

    2014-11-01

    Masking the bitter taste of Ondansetron hydrochloride (ONS) may improve palatability, acceptance and compliance of ONS products. ONS-loaded, taste-masked microspheres were prepared with a polycationic pH-sensitive polymer and 3(2) full factorial design (FFD) was applied to optimize microsphere batches. Solvent evaporation, in acetone--methanol/liquid paraffin system, was used to prepare taste-masked ONS microspheres. The effect of varying drug/polymer (D/P) ratios on microspheres characteristics were studied by 3(2) FFD. Desirability function was used to search the optimum formulation. Microspheres were evaluated by FTIR, XRD and DSC to examine interaction and effect of microencapsulation process. In vitro taste assessment approach based on bitterness threshold and drug release was used to assess bitterness scores. Prepared ONS microspheres were spherical and surface was wrinkled. ONS was molecularly dispersed in microspheres without any incompatibility with EE100. In hydrochloric acid buffer pH 1.2, ONS released completely from microsphere in just 10 min. Contrary to this, ONS release at initial 5 min from taste-masked microspheres was less than the bitterness threshold. Full factorial design and in vitro taste assessment approach, coupled together, was successfully applied to develop and optimize batches of ONS incorporated taste-masked microspheres.

  7. Effect of WOW process parameters on morphology and burst release of FITC-dextran loaded PLGA microspheres.

    Science.gov (United States)

    Mao, Shirui; Xu, Jing; Cai, Cuifang; Germershaus, Oliver; Schaper, Andreas; Kissel, Thomas

    2007-04-04

    Using fluorescein isothiocyanate labeled dextran (FITC-dextran 40, FD40) as a hydrophilic model compound, microspheres were prepared by a WOW double emulsion technique. Influence of process parameters on microsphere morphology and burst release of FD40 from PLGA microspheres was studied. Internal morphology of microspheres was investigated by stereological method via cryo-cutting technique and scanning electron microscopy (SEM). Drug distribution in microspheres was observed with confocal laser scanning microscopy (CLSM). Polymer nature (RG503 and RG503H) had significant influence on the micro-morphology of microspheres. Increase in continuous water phase volume (W2) led to increased surface porosity but decreased internal porosity. By increasing PVA concentration in the continuous phase from 0.1 to 1%, particle size changed marginally but burst release decreased from 12.2 to 5.9%. Internal porosity of microspheres decreased considerably with increasing polymer concentration. Increase in homogenization speed during the primary emulsion preparation led to decreased internal porosity. Burst release decreased with increasing drug loading but increased with drug molecular weight. Drug distribution in microspheres depended on preparation method. The porosity of microspheres decreased with time in the diffusion stage, but internal morphology had no influence on the release behavior in the bioerosion stage. In summary, surface porosity and internal morphology play a significant role in the release of hydrophilic macromolecules from biodegradable microspheres in the initial release phase characterized by pore diffusion.

  8. 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.

  9. Magnetic Ganoderma lucidum spore microspheres: A novel material to immobilize CotA multicopper oxidase for dye decolorization

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Lili [School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Yan, E-mail: wangy_msn@hit.edu.cn [School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhao, Min [College of Life Science, Northeast Forestry University, Harbin 150040 (China); Song, Jinzhu [School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Wang, Jueyu; Jin, Zijing [College of Life Science, Northeast Forestry University, Harbin 150040 (China)

    2016-08-05

    Highlights: • Hollow microspheres were obtained from Ganoderma lucidum spores. • Novel magnetic microspheres were prepared by load hollow spore microspheres with Fe{sub 3}O{sub 4} nanoparticles. • CotA multicopper oxidase was immobilized on the magnetic spore microspheres for indigo carmine decolorization. • The immobilized CotA displayed higher decolorization capability and reusability. - Abstract: In this study, hollow microspheres were obtained from Ganoderma lucidum spores. Then the hollow microspheres were loaded with Fe{sub 3}O{sub 4} nanoparticles to prepare novel magnetic spore microspheres. TEM images and X-ray diffractometry demonstrated that the Fe{sub 3}O{sub 4} nanoparticles were incorporated throughout the spore microsphere. CotA multicopper oxidase was chosen as biomacromolecule to study the loading ability of the magnetic spore microspheres. The combination of the CotA enzyme with the microsphere was observed by laser scanning confocal microscope. The loaded amount of CotA on the microspheres was 75 mg/g when the CotA concentration was 1.2 mg/mL and the activity recovery of the immobilized CotA was 81%. The magnetic microspheres loaded with CotA, which can be easily and quickly recovered by an external magnetic field, were used for dye decolorization. After 1 h decolorization, 99% of the indigo carmine has been removed by 10 mg microspheres. In addition, the immobilized CotA retained 75% of activity after 10 consecutive cycles, which indicated that the magnetic spore microspheres are good support material for immobilization of the enzyme.

  10. Magnetic Ganoderma lucidum spore microspheres: A novel material to immobilize CotA multicopper oxidase for dye decolorization

    International Nuclear Information System (INIS)

    Fan, Lili; Wang, Yan; Zhao, Min; Song, Jinzhu; Wang, Jueyu; Jin, Zijing

    2016-01-01

    Highlights: • Hollow microspheres were obtained from Ganoderma lucidum spores. • Novel magnetic microspheres were prepared by load hollow spore microspheres with Fe_3O_4 nanoparticles. • CotA multicopper oxidase was immobilized on the magnetic spore microspheres for indigo carmine decolorization. • The immobilized CotA displayed higher decolorization capability and reusability. - Abstract: In this study, hollow microspheres were obtained from Ganoderma lucidum spores. Then the hollow microspheres were loaded with Fe_3O_4 nanoparticles to prepare novel magnetic spore microspheres. TEM images and X-ray diffractometry demonstrated that the Fe_3O_4 nanoparticles were incorporated throughout the spore microsphere. CotA multicopper oxidase was chosen as biomacromolecule to study the loading ability of the magnetic spore microspheres. The combination of the CotA enzyme with the microsphere was observed by laser scanning confocal microscope. The loaded amount of CotA on the microspheres was 75 mg/g when the CotA concentration was 1.2 mg/mL and the activity recovery of the immobilized CotA was 81%. The magnetic microspheres loaded with CotA, which can be easily and quickly recovered by an external magnetic field, were used for dye decolorization. After 1 h decolorization, 99% of the indigo carmine has been removed by 10 mg microspheres. In addition, the immobilized CotA retained 75% of activity after 10 consecutive cycles, which indicated that the magnetic spore microspheres are good support material for immobilization of the enzyme.

  11. Oxaliplatin loaded PLAGA microspheres: design of specific release profiles.

    Science.gov (United States)

    Lagarce, F; Cruaud, O; Deuschel, C; Bayssas, M; Griffon-Etienne, G; Benoit, J

    2002-08-21

    Oxaliplatin loaded PLAGA microspheres have been prepared by solvent extraction process. Parameters affecting the release kinetics in vitro have been studied in order to design specific release profiles suitable for direct intra-tumoral injection. By varying the nature and the relative proportions of different polymers we managed to prepare microspheres with good encapsulation efficiency (75-90%) and four different release profiles: zero order kinetics (type II) and the classical sigmoïd release profile with three different sizes of plateau and burst. These results, if correlated with in vivo activity, are promising to enhance effectiveness of local tumor treatment.

  12. Carbidopa/levodopa-loaded biodegradable microspheres: in vivo evaluation on experimental Parkinsonism in rats.

    Science.gov (United States)

    Arica, Betül; Kaş, H Süheyla; Moghdam, Amir; Akalan, Nejat; Hincal, A Atilla

    2005-02-16

    The purpose of this study was to prepare and characterize injectable carbidopa (CD)/levodopa (LD)-loaded Poly(L-lactides) (L-PLA), Poly(D,L-lactides) (D,L-PLA) and Poly(D,L-lactide-co-glycolide) (PLAGA) microspheres for the intracerebral treatment of Parkinson's disease. The microspheres were prepared by solvent evaporation method. The polymers' (L-PLA, D,L-PLA and PLAGA) concentrations were 10% (w/w) in the organic phase; the emulsifiers [sodium carboxymethylcellulose (NaCMC):sodium oleate (SO) and Polyvinyl alcohol (PVA):SO mixture (4:1 w/v)] concentrations were 0.75% in the aqueous phase. Microspheres were analyzed for morphological characteristics, size distribution, drug loading and in vitro release. The release profile of CD/LD from microspheres was characterized in the range of 12-35% within the first hour of the in vitro release experiment. The efficiency of CD- and LD-encapsulated microspheres to striatal transplantation and the altering of apomorphine-induced rotational behavior in the 6-hydroxydopamine (6-OHDA) unilaterally lesioned rat model were also tested. 6-OHDA/CD-LD-loaded microsphere groups exhibited lower rotation scores than 6-OHDA/Blank microsphere groups as early as 1 week postlesion. These benefits continued throughout the entire experimental period and they were statistically significant during the 1, 2 and 8 weeks (p<0.05). CD/LD-loaded microspheres were specifically prepared to apply as an injectable dosage forms for brain implantation.

  13. Microencapsulação do agente quelante sulfoxina em microesferas de quitosana preparadas por spray drying como novo adsorvente para íons metálicos Microencapsulation of the chelating agent sulfoxine into microspheres of chitosan prepared by spray drying as a new adsorbent for metalic ions

    Directory of Open Access Journals (Sweden)

    Luciano Vitali

    2008-01-01

    Full Text Available In this work, a new adsorbent was prepared by microencapsulation of sulfoxine into chitosan microspheres by the spray drying technique. The new adsorbent was characterized by Raman spectroscopy, scanning electron microscopy and microanalysis of energy dispersive X-rays. The Cu(II adsorption was studied as a function of pH, time and concentration. The optimum pH was found to be 6.0. The kinetic and equilibrium data showed that the adsorption process followed the pseudo second-order kinetic model and the Langmuir isotherm model over the entire concentration range. An increase of 8.0% in the maximum adsorption capacity of the adsorbent (53.8 mg g-1 was observed as compared to chitosan glutaraldehyde cross-linked microspheres.

  14. Sintered nuclear fuel and method of preparing same

    International Nuclear Information System (INIS)

    Abate-Daga, G.; Amato, I.

    1975-01-01

    A description is given of a method of preparing a nuclear fuel containing a consumable nuclear poison uniformly distributed therein in the form of coated micro-spheres of between 10 and 2,000 microns diameter, consisting in preparing sintered micro-spheres of the consumable poison, covering those micro-spheres with a protective coating and incorporating the coated micro-spheres into uranium dioxide powder, followed by sintering

  15. [Optimization of calcium alginate floating microspheres loading aspirin by artificial neural networks and response surface methodology].

    Science.gov (United States)

    Zhang, An-yang; Fan, Tian-yuan

    2010-04-18

    To investigate the preparation and optimization of calcium alginate floating microspheres loading aspirin. A model was used to predict the in vitro release of aspirin and optimize the formulation by artificial neural networks (ANNs) and response surface methodology (RSM). The amounts of the material in the formulation were used as inputs, while the release and floating rate of the microspheres were used as outputs. The performances of ANNs and RSM were compared. ANNs were more accurate in prediction. There was no significant difference between ANNs and RSM in optimization. Approximately 90% of the optimized microspheres could float on the artificial gastric juice over 4 hours. 42.12% of aspirin was released in 60 min, 60.97% in 120 min and 78.56% in 240 min. The release of the drug from the microspheres complied with Higuchi equation. The aspirin floating microspheres with satisfying in vitro release were prepared successfully by the methods of ANNs and RSM.

  16. Controllable growth and photocatalytic activity of Cu{sub 2}O solid microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hong; Zhang, Junying, E-mail: zjy@buaa.edu.cn; Wang, Mei

    2013-09-01

    Graphical abstract: - Highlights: • 3 μm uniform Cu{sub 2}O solid microspheres with abundant nanopores are achieved. • NH{sub 2}OH·HCl and SDS are main factors that manipulate morphologies of Cu{sub 2}O particles. • Surface features of microspheres influenced the photocatalytic activity of Cu{sub 2}O. • Microspheres are transforming to polyhedrons with extended holding time. - Abstract: A series of Cu{sub 2}O solid microspheres with different surface features were prepared and their photocatalytic activities were studied. The experiment conditions were investigated and the formation mechanism was explored systematically. It was found that varying the amounts of NH{sub 2}OH·HCl reductant in alkaline solutions changed the reaction process and thus altered the surface features of Cu{sub 2}O microspheres. Sodium dodecyl sulfate (SDS) surfactant, introduced as a morphology directing agent, caused the nuclei aggregation and growth process of Cu{sub 2}O solid microspheres by precisely realizing the opposite charges’ directional attraction. This SDS-mediated method can be readily extended to synthesizing solid microspheres of other metal oxides. Meanwhile, it was found that Cu{sub 2}O solid microspheres with abundant nanopores on the surface showed much higher efficient catalytic activity for decoloring methyl orange (MO) aqueous solution than with other surface features under visible light irradiation. Furthermore, we found that prolonging the holding time made Cu{sub 2}O microspheres transform to polyhedrons.

  17. Development and optimization of enteric coated mucoadhesive microspheres of duloxetine hydrochloride using 32 full factorial design

    Science.gov (United States)

    Setia, Anupama; Kansal, Sahil; Goyal, Naveen

    2013-01-01

    Background: Microspheres constitute an important part of oral drug delivery system by virtue of their small size and efficient carrier capacity. However, the success of these microspheres is limited due to their short residence time at the site of absorption. Objective: The objective of the present study was to formulate and systematically evaluate in vitro performance of enteric coated mucoadhesive microspheres of duloxetine hydrochloride (DLX), an acid labile drug. Materials and Methods: DLX microspheres were prepared by simple emulsification phase separation technique using chitosan as carrier and glutaraldehyde as a cross-linking agent. Microspheres prepared were coated with eudragit L-100 using an oil-in-oil solvent evaporation method. Eudragit L-100was used as enteric coating polymer with the aim to release the drug in small intestine The microspheres prepared were characterized by particle size, entrapment efficiency, swelling index (SI), mucoadhesion time, in vitro drug release and surface morphology. A 32 full factorial design was employed to study the effect of independent variables polymer-to-drug ratio (X1) and stirring speed (X2) on dependent variables, particle size, entrapment efficiency, SI, in vitro mucoadhesion and drug release up to 24 h (t24). Results: Microspheres formed were discrete, spherical and free flowing. The microspheres exhibited good mucoadhesive property and also showed high percentage entrapment efficiency. The microspheres were able to sustain the drug release up to 24 h. Conclusion: Thus, the prepared enteric coated mucoadhesive microspheres may prove to be a potential controlled release formulation of DLX for oral administration. PMID:24167786

  18. Iron Nanoparticles-Encapsulating Silica Microspheres for Arterial Embolization Hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z; Kawashita, M, E-mail: zhixia@ecei.tohoku.ac.jp [Graduate School of Biomedical Engineering, Tohoku University (Japan)

    2011-10-29

    We attempted to prepare {alpha}-Fe-encapsulating silica ({alpha}FeSi) microspheres by a sol-gel process using tetramethoxysilane (TMOS) in water-in-oil emulsion. The effect of preparation conditions on the structure, magnetic and heating properties of resultant products were investigated. Oil phase consisted of kerosene with 32 wt% of surfactants (sorbitan monooleate / sorbitan monostearate in 3:1 weight ratio). Water phase consisted of TMOS, ethanol (CH{sub 2}CH{sub 3}OH), water and iron nitrate (Fe(NO{sub 3}){sub 3{center_dot}}9H{sub 2}O) with TMOS / CH{sub 2}CH{sub 3}OH/H{sub 2}O/Fe{sup 3+} in 1:7.4:16.2:0.4{approx}1.2 molar ratio. Fe{sup 3+}-containing silica gel (FeSiG) microspheres 5 to 30 {mu}m in size were successfully obtained by adding the water phase into the oil phase at 60 deg. C under stirring of 1500 rpm for 100 min. {alpha}FeSi microspheres was obtained by heating the FeSiG microspheres at 850deg. C in argon atmosphere. The obtained {alpha}FeSi microspheres have a saturation magnetization (Ms) up to 21 emu g{sup -1} and a coercive force (Hc) of 133 Oe. The in vitro heating generation was evaluated under an alternating current (AC) magnetic field of 300 Oe and 100 kHz.

  19. 5-Fluorouracil:carnauba wax microspheres for chemoembolization: an in vitro evaluation.

    Science.gov (United States)

    Benita, S; Zouai, O; Benoit, J P

    1986-09-01

    5-Fluorouracil:carnauba wax microspheres were prepared using a meltable dispersion process with the aid of a surfactant as a wetting agent. It was noted that only hydrophilic surfactants were able to wet the 5-fluorouracil and substantially increased its content in the microspheres. No marked effect was observed in the particle size distribution of the solid microspheres as a function of the nature of the surfactant. Increasing the stirring rate in the preparation process decreased, first, the mean droplet size of the emulsified melted dispersion in the vehicle during the heating process, and, consequently, the mean particle size of the solidified microspheres during the cooling process. 5-Fluorouracil cumulative release from the microspheres followed first-order kinetics, as shown by nonlinear regression analysis. Although the kinetic results were not indicative of the true release mechanism from a single microsphere, it was believed that 5-fluorouracil release from the microspheres was probably governed by a dissolution process, rather than by a leaching process through the carnauba wax microspheres.

  20. Eudragit-coated dextran microspheres of 5-fluorouracil for site-specific delivery to colon.

    Science.gov (United States)

    Rai, Gopal; Yadav, Awesh K; Jain, Narendra K; Agrawal, Govind P

    2016-01-01

    Objective of the present investigation was to prepare and evaluate the potential of enteric coated dextran microspheres for colon targeting of 5-fluorouracil (5-FU). Dextran microspheres were prepared by emulsification-crosslinking method and the formulation variables studied included different molecular weights of dextran, drug:polymer ratio, volume of crosslinking agent, stirring speed and time. Enteric coating (Eudragit S-100) of dextran microspheres was performed by oil-in-oil solvent evaporation method using different coat:core ratios (4:1 or 8:1). Uncoated and coated dextran microspheres were characterized by particle size, surface morphology, entrapment efficiency, DSC, in vitro drug release in the presence of dextranase and 2% rat cecal contents. The release study of 5-FU from coated dextran microspheres was pH dependent. No release was observed at acidic pH; however, the drug was released quickly where Eudragit starts solublizing there was continuous release of drug from the microspheres. Organ distribution study was suggested that coated dextran microspheres retard the release of drug in gastric and intestinal pH environment and released of drug from microspheres in colon due to the degradation of dextran by colonic enzymes.

  1. Glass microspheres covering film: first field evaluations

    International Nuclear Information System (INIS)

    Magnani, G.; Filippi, F.

    2006-01-01

    A trial was carried out to evaluate, in the North-Centre of Italy, the behaviour in field of a new plastic covering film, prepared with the inclusion of empty glass microspheres (Solex). The trial was conducted on tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). The new film was compared to a covering film with the same optical (diffuse light) and constitutional (co-extruded three layers EVA-WPE) characteristics. Since the first results, the innovative film showed a better behaviour than the control one. It presented light and thermal conditions (lower temperature during the day and slightly higher temperature in the night, compared to the control film) that allowed a better growth and yield than the control film. The growth analysis of tomato showed that plants grown under glass microsphere film had an higher growth rate (dry weight/days) and thickness of leaves compared to the control one. The yield of tomato and eggplant presented an increase in plants cultivated under the innovative film, especially for number and weight of fruits. The commercial quality did not show any differences between the films, except for the flesh hardness of tomato: this could be explained with the fact that the glass microspheres film provides environmental conditions avoiding plant stress during some stages of its cycle [it

  2. Adsorption behavior of protein onto siloxane microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bailing [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)]. E-mail: Blliuchem@hotmail.com; Cao Shunsheng [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Deng Xiaobo [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Li Songjun [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Luo Rong [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)

    2006-09-15

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption.

  3. Adsorption behavior of protein onto siloxane microspheres

    International Nuclear Information System (INIS)

    Liu Bailing; Cao Shunsheng; Deng Xiaobo; Li Songjun; Luo Rong

    2006-01-01

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption

  4. Synthesis of Poly(styrene-acrylates-acrylic acid Microspheres and Their Chemical Composition towards Colloidal Crystal Films

    Directory of Open Access Journals (Sweden)

    Luis A. Ríos-Osuna

    2016-01-01

    Full Text Available In this paper, polystyrene colloidal microspheres have been prepared using hexyl acrylate (HA, ethylhexyl acrylate (EHA, isooctyl acrylate (IOA, butyl acrylate (BA, or isobutyl acrylate (IBA as comonomers. Microspheres with diameters from 212 to 332 nm and with a polystyrene content of 65–78% were prepared. The particles prepared in this work do not present the typical core-shell structure; as a consequence, DSC analysis showed that the microspheres exhibited only one Tg. TEM images show that the particles with comonomer content below ~30% were spherical and regular. Microspheres containing comonomer between 21 to 25% produced the less brittle films showing very iridescent colors. The films prepared from microspheres containing hexyl, ethylhexyl, and isooctyl acrylate as comonomers are firmly attached to the substrate due to their adhesive properties. The large decrease of the fragility observed in these films makes them much more attractive materials in sensing applications.

  5. Formulation and characterization of ketoprofen embedded polycaprolactone microspheres using solvent evaporation method

    Directory of Open Access Journals (Sweden)

    Pankaj Wagh

    2015-07-01

    Full Text Available The purpose of this study was to prepare polymeric microspheres containing Ketoprofen (KFN by single emulsion [oil-in-water (o/w] solvent evaporation method. Polycaprolactone (PCL, biocompatible polymer, was used for the preparation of sustained released microspheres of KFN. A Plackett–Burman design was employed by using the Design-Expert® software (Version- 9.0.3.1, Stat-Ease Inc., Minneapolis, MN. Eleven factors out of six processing factors were investigated in order to enhance the encapsulation efficiency (EE of the microspheres. The resultant microspheres were characterized for their size, morphology, EE, and drug release. Imaging of particles was performed by field emission scanning electron microscopy. Interaction between the drug and polymers were investigated by Fourier transform infrared (FTIR spectroscopy, X-ray powder diffractometry (XRPD and Differential Scanning Calorimetry (DSC. Graphical and mathematical analyses of the design showed that concentration of factor PCL (B and varying speed (F, revolution per minute, rpm were significant negative effect on the EE and identified as the significant factor determining the EE of the microspheres. The microspheres showed high % EE (31.18 % to 96.81 %. The microspheres were found to be discrete, oval with porous surface. The FTIR analysis confirmed no interaction of KFN with the polymer. The XRPD revealed the dispersion of drug within microspheres formulation. Sustained drug release profile over 12 h was achieved by PCL polymer. In conclusion, polymeric microspheres containing KFN can be successfully prepared using the technique of experimental design, and these results helped in finding the optimum formulation variables for EE of microspheres.

  6. Formulation and Evaluation of Microsphere Based Oro Dispersible Tablets of Itopride Hcl

    Directory of Open Access Journals (Sweden)

    S.S Agrawal

    2012-09-01

    Full Text Available Background The purpose of the present work is to mask the intensely bitter taste of Itopride HCl and to formulate an Oro dispersible tablet (ODT of the taste-masked drug by incorporation of microspheres in the tablets for use in specific populations viz. pediatrics, geriatrics and patients experiencing difficulty in swallowing.Methods:With this objective in mind, microspheres loaded with Itopride HCl were prepared by solvent evaporation method using acetone as solvent for pH-sensitive polymer, Eudragit EPO and light liquid paraffin as the encapsulating medium. The prepared microspheres were characterized with regard to yield, drug content, flow properties, particle size and size distribution, surface features, in vitro drug release and taste. The ODTs so prepared from these microspheres were evaluated for hardness, thickness, weight variation, friability, disintegration time, drug content, wetting time, water absorption ratio, moisture uptake, in vitro dispersion, in vitro disintegration, in vitro drug release and stability. Results:The average size of microspheres was found to be satisfactory in terms of the size and size distribution. Microspheres prepared were of a regular spherical shape. Comparison of the dissolution profiles of microspheres in different pH media showed that microspheres having drug: polymer ratio of 1:2 produced a retarding effect in simulated salivary fluid (pH 6.8 and were further used for formulation into ODTs after addition of suitable amounts of excipients such as superdisintegrant, diluent, sweetener and flavor of directly compressible grade. ConclusionsEffective taste-masking was achieved for Itopride HCl by way of preparation of microspheres and ODTs of acceptable characteristics.

  7. Formulation and evaluation of microsphere based oro dispersible tablets of itopride hcl

    Directory of Open Access Journals (Sweden)

    Shah Sanjay

    2012-09-01

    Full Text Available Abstract Background The purpose of the present work is to mask the intensely bitter taste of Itopride HCl and to formulate an Oro dispersible tablet (ODT of the taste-masked drug by incorporation of microspheres in the tablets for use in specific populations viz. pediatrics, geriatrics and patients experiencing difficulty in swallowing. Methods With this objective in mind, microspheres loaded with Itopride HCl were prepared by solvent evaporation method using acetone as solvent for pH-sensitive polymer, Eudragit EPO and light liquid paraffin as the encapsulating medium. The prepared microspheres were characterized with regard to yield, drug content, flow properties, particle size and size distribution, surface features, in vitro drug release and taste. The ODTs so prepared from these microspheres were evaluated for hardness, thickness, weight variation, friability, disintegration time, drug content, wetting time, water absorption ratio, moisture uptake, in vitro dispersion, in vitro disintegration, in vitro drug release and stability. Results The average size of microspheres was found to be satisfactory in terms of the size and size distribution. Microspheres prepared were of a regular spherical shape. Comparison of the dissolution profiles of microspheres in different pH media showed that microspheres having drug: polymer ratio of 1:2 produced a retarding effect in simulated salivary fluid (pH 6.8 and were further used for formulation into ODTs after addition of suitable amounts of excipients such as superdisintegrant, diluent, sweetener and flavor of directly compressible grade. Conclusions Effective taste-masking was achieved for Itopride HCl by way of preparation of microspheres and ODTs of acceptable characteristics.

  8. Formulation and evaluation of microsphere based oro dispersible tablets of itopride hcl.

    Science.gov (United States)

    Shah, Sanjay; Madan, Sarika; Agrawal, Ss

    2012-09-03

    The purpose of the present work is to mask the intensely bitter taste of Itopride HCl and to formulate an Oro dispersible tablet (ODT) of the taste-masked drug by incorporation of microspheres in the tablets for use in specific populations viz. pediatrics, geriatrics and patients experiencing difficulty in swallowing. With this objective in mind, microspheres loaded with Itopride HCl were prepared by solvent evaporation method using acetone as solvent for pH-sensitive polymer, Eudragit EPO and light liquid paraffin as the encapsulating medium. The prepared microspheres were characterized with regard to yield, drug content, flow properties, particle size and size distribution, surface features, in vitro drug release and taste. The ODTs so prepared from these microspheres were evaluated for hardness, thickness, weight variation, friability, disintegration time, drug content, wetting time, water absorption ratio, moisture uptake, in vitro dispersion, in vitro disintegration, in vitro drug release and stability. The average size of microspheres was found to be satisfactory in terms of the size and size distribution. Microspheres prepared were of a regular spherical shape. Comparison of the dissolution profiles of microspheres in different pH media showed that microspheres having drug: polymer ratio of 1:2 produced a retarding effect in simulated salivary fluid (pH 6.8) and were further used for formulation into ODTs after addition of suitable amounts of excipients such as superdisintegrant, diluent, sweetener and flavor of directly compressible grade. Effective taste-masking was achieved for Itopride HCl by way of preparation of microspheres and ODTs of acceptable characteristics.

  9. Hollow microspheres with a tungsten carbide kernel for PEMFC application.

    Science.gov (United States)

    d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

    2011-07-28

    Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

  10. Formulation and evaluation of matrix microspheres for simultaneous ...

    African Journals Online (AJOL)

    The prepared microspheres were characterized for their micromeritic properties and drug loading, as well as by infrared spectroscopy (IR), differential scanning calorimetry (DSC), x-ray powder diffractometry (XRD) and scanning electron microscopy (SEM). The in vitro release studies were performed in pH 7.4, phosphate ...

  11. Formulation and Optimization of Celecoxib-Loaded Microspheres ...

    African Journals Online (AJOL)

    factors in the preparation of celecoxib-loaded microspheres. Methods: ... made with biodegradable polymers, are ... filtration on Whatman filter paper no.1 and washed 4 - 5 times with n-hexane [11]. The product was then air-dried at room.

  12. Influence of different formulations and process parameters during the preparation of drug-loaded PLGA microspheres evaluated by multivariate data analysis

    Directory of Open Access Journals (Sweden)

    Vysloužil Jakub

    2014-12-01

    Full Text Available The main objective of this study was to evaluate the influence of the formulation and process parameters on PLGA microparticles containing a practically insoluble model drug (ibuprofen prepared by the o/w solvent evaporation method. Multivariate data analysis was used. The effects of altered stirring speed of a mechanical stirrer (600, 1000 rpm, emulsifier concentrations (PVA concentration 0.1 %, 1 % and solvent selection (dichloromethane, ethyl acetate on microparticle characteristics (encapsulation efficiency, drug loading, burst effect were observed. It was found that with increased stirring speed, the PVA concentration or the use of ethyl acetate had a significantly negative effect on encapsulation efficiency. In addition, ethyl acetate had an adverse effect on the burst effect, while increased stirring speed had the opposite effect. Drug load was not affected by any particular variable, but rather by the interactions of evaluated variables.

  13. The synthesis and photocatalytic activity of ZnSe microspheres

    International Nuclear Information System (INIS)

    Cao Huaqiang; Xiao Yujiang; Zhang Sichun

    2011-01-01

    This paper reports the synthesis of semiconductor ZnSe microspheres composed of nanoparticles via a solvothermal route between the organic molecule selenophene (C 4 H 4 Se) and ZnCl 2 without adding any surfactant. The ZnSe microspheres were characterized by x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), specific surface area measurement, and photoluminescence (PL) spectra. A strong and broad blue PL emission at 443 nm in wavelength (∼2.79 eV in photon energy) is attributed to the near-band-edge (NBE) emission of ZnSe, while the 530 nm peak is a defect-related (DL) emission. The photocatalytic activity of the as-prepared ZnSe microspheres was evaluated by photodegradation of methyl orange (MO) dye under ultraviolet (UV) light and visible light irradiation. The degradations of MO reach 94% or 95.1%, close to 100%, in the presence of the as-synthesized ZnSe microspheres or commercial ZnSe powder after 7 or 10 h under UV irradiation, respectively. Meanwhile the degradations of MO reach 94.3% or 60.6% in the presence of the as-synthesized ZnSe microspheres or commercial ZnSe powder after 12 h, respectively. The degradation rate of ZnSe microspheres is twice that of ZnSe commercial powder under UV light irradiation, and three times under visible light irradiation. The degradation process of MO dye on ZnSe microspheres under UV or visible light is also discussed.

  14. Polymer-coated albumin microspheres as carriers for intravascular tumour targeting of cisplatin.

    Science.gov (United States)

    Verrijk, R; Smolders, I J; McVie, J G; Begg, A C

    1991-01-01

    We used a poly-lactide-co-glycolide polymer (PLAGA 50:50) to formulate cisplatin (cDDP) into microspheres designed for intravascular administration. Two systems were developed. PLAGA-coated albumin microspheres and microspheres consisting of PLAGA only. PLAGA-coated microspheres displayed a mean diameter of 31.8 +/- 0.9 microns and a payload of 7.5% cDDP (w/w). Solid PLAGA microspheres exhibited a mean diameter of 19.4 +/- 0.6 microns and a payload of 20% cDDP. Release characteristics and in vitro effects on L1210 leukemia and B16 melanoma cell lines were investigated. Both types of microsphere overcame the initial rapid release of cDDP (burst effect), and PLAGA-coated albumin microspheres also showed a lag phase of approximately 30 min before cDDP release began. PLAGA-coated albumin microspheres released most of their payload through diffusion, and the coating eventually cracked after 7 days' incubation in saline supplemented with 0.1% Tween at 37 degrees C, enabling the release of any cDDP remaining. Effects of platinum, pre-released from PLAGA-coated albumin microspheres on the in vitro growth of L1210 cells were comparable with those of standard formulations (dissolved) of cDDP. Material released from non-drug-loaded PLAGA microspheres had no effect on L1210 cell growth, suggesting the absence of cytotoxic compounds in the matrix. The colony-forming ability of B16 cells was also equally inhibited by standard cDDP and pre-released drug. These studies show that formulation of cDDP in PLAGA-based microspheres prevents the rapid burst effect of cDDP seen in previous preparations and offers an improved system of administration for hepatic artery infusion or adjuvant therapy, enabling better clinical handling and the promise of a higher ratio of tumour tissue to normal tissue.

  15. The physical and chemical stability of suspensions of sustained-release diclofenac microspheres.

    Science.gov (United States)

    Lewis, L; Boni, R L; Adeyeye, C M

    1998-01-01

    The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.

  16. Ammonolysis-induced solvent removal: a facile approach for solidifying emulsion droplets into PLGA microspheres.

    Science.gov (United States)

    Kim, Jayoung; Hong, Dasom; Chung, Younglim; Sah, Hongkee

    2007-12-01

    An ammonolysis-based microencapsulation technique useful for the preparation of biodegradable microspheres was described in this study. A dispersed phase consisting of poly- d, l-lactide- co-glycolide, progesterone, and methyl chloroacetate was emulsified in an aqueous phase. Upon addition of ammonia solution, the emulsion droplets were quickly transformed into poly- d, l-lactide- co-glycolide microspheres laden with progesterone. Rapid solvent removal was accompanied by ammonolysis. The chemical reaction converted water-immiscible methyl chloroacetate to water-miscible chloroacetamide and methanol. Chloroacetamide formation was proved by (1)H NMR and ESI-MS studies. Thermogravimetric analysis showed that the microspheres contained only small amounts of residual methyl chloroacetate. Incorporation efficiencies of progesterone ranged from 64.3 +/- 1.1 to 72.8 +/- 0.3%, depending upon microsphere formulations. X-ray powder diffractometry analysis substantiated that no polymorphic transition of progesterone occurred during microencapsulation. To evaluate the feasibility of this new method against the commonly used microencapsulation method, microspheres were also prepared by a typical dichloromethane-based solvent evaporation process. The important attributes of microspheres prepared from both methods were characterized for comparison. The new ammonolysis-based microencapsulation process showed interesting features distinct from those of the solvent evaporation process. The microencapsulation process reported in this study might be applicable in loading pharmaceuticals into various polymeric microspheres.

  17. Electrodepositing of Au on hollow PS micro-spheres

    International Nuclear Information System (INIS)

    Sun Jingyuan; Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zhang Wei; Zhang Lin; Chen Jing

    2010-01-01

    Using the self-regulating new micro-sphere electrodepositing device, the techniques of electrodepositing gold on hollow PS micro-spheres were established. The experiment was carried out under the following conditions: voltage was about 0.7 ∼ 0.8 V, current density was 2.0 mA · cm -2 , the temperature was 45 degree C, cathode rotating rate was 250 r · min -1 , flow rate of the solution was 7 mL · min -1 · cm -2 . Hollow gold-plated micro-spheres were prepared with well spherical symmetry, uniform thickness and surface smoothness under 500 nm. The speed of the gold depositing was 6 μm · h -1 . (authors)

  18. A review on target drug delivery: magnetic microspheres

    Directory of Open Access Journals (Sweden)

    Amit Chandna

    2013-01-01

    Magnetic microsphere is newer approach in pharmaceutical field. Magnetic microspheres as an alternative to traditional radiation methods which use highly penetrating radiation that is absorbed throughout the body. Its use is limited by toxicity and side effects. The aim of the specific targeting is to enhance the efficiency of drug delivery & at the same time to reduce the toxicity & side effects. This kind of delivery system is very much important which localises the drug to the disease site. In this larger amount of freely circulating drug can be replaced by smaller amount of magnetically targeted drug. Magnetic carriers receive magnetic responses to a magnetic field from incorporated materials that are used for magnetic microspheres are chitosan, dextran etc. magnetic microspheres can be prepared from a variety of carrier material. One of the most utilized is serum albumin from human or other appropriate species. Drug release from albumin microspheres can be sustained or controlled by various stabilization procedures generally involving heat or chemical cross-linking of the protein carrier matrix.

  19. Pharmacodynamics of diclofenac from novel Eudragit entrapped microspheres.

    Science.gov (United States)

    Momoh, M A; Kenechukwu, F C; Adedokun, M O; Odo, C E; Attama, A A

    2014-05-01

    Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit® RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 ± 0.11, 88.14 ± 0.16 and 85.50 ± 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 ± 0.01-479 ± 0.21 µm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit® polymers would likely offer a reliable and alternative means of delivering DS orally.

  20. Enteric-coated epichlorohydrin crosslinked dextran microspheres for site-specific delivery to colon.

    Science.gov (United States)

    Rai, Gopal; Yadav, Awesh K; Jain, Narendra K; Agrawal, Govind P

    2015-01-01

    Enteric-coated epichlorohydrin crosslinked dextran microspheres containing 5-Fluorouracil (5-FU) for colon drug delivery was prepared by emulsification-crosslinking method. The formulation variables studied includes different molecular weights of dextran, volume of crosslinking agent, stirring speed, time and temperature. Dextran microspheres showed mean entrapment efficiencies ranging between 77 and 87% and mean particle size ranging between 10 and 25 µm. About 90% of drug was released from uncoated dextran microspheres within 8 h, suggesting the fast release and indicated the drug loaded in uncoated microspheres, released before they reached colon. Enteric coating (Eudragit-S-100 and Eudragit-L-100) of dextran microspheres was performed by oil-in-oil solvent evaporation method. The release study of 5-FU from coated dextran microspheres was complete retardation in simulated gastric fluid (pH 1.2) and once the coating layer of enteric polymer was dissolved at higher pH (7.4 and 6.8), a controlled release of the drug from the microspheres was observed. Further, the release of drug was found to be higher in the presence of dextranase and rat caecal contents, indicating the susceptibility of dextran microspheres to colonic enzymes. Organ distribution and pharmacokinetic study in albino rats was performed to establish the targeting potential of optimized formulation in the colon.

  1. Cephradin-plaga microspheres for sustained delivery to cattle.

    Science.gov (United States)

    Ustariz-Peyret, C; Coudane, J; Vert, M; Kaltsatos, V; Boisramé, B

    1999-01-01

    In the field of controlled drug delivery, most of the reported work is aimed at introducing new systems, or at providing basic information on the critical parameters which affect release profiles in vitro and occasionally in vivo. The situation is totally different when one wants to fulfil the specific requirements imposed by the marketing of a sustained release device to be used in humans or in animals eaten by human beings. The control of the release characteristics is then a difficult challenge. In this work, attempts were made to combine cephradin, a hydrophilic beta-lactam antibiotic, and bioresorbable polymeric matrices of a poly(alpha-hydroxy acid) in the form of microspheres with the aim of delivering the antibiotic to cattle at a dose rate of 4-5 mg/kg/day over a 3-4 days period after i.m. injection. PLAGA aliphatic polyesters were selected because they are already FDA approved as matrices. The solvent evaporation technique using PVA as the emulsion stabilizer was selected because it is efficient and can be extended to an industrial scale. Various experimental conditions were used in order to obtain the highest encapsulation yields compatible with the desired specifications. Decreasing the volume of the aqueous phase and adding a water-miscible organic solvent/non-solvent of cephradin failed. In contrast, microspheres containing up to 30% cephradin were prepared after addition of sodium chloride to the aqueous dispersing phase. The amount of entrapped drug was raised to 40% by decreasing the temperature and the pressure. Preliminary investigations using dogs showed that 20% cephradin microspheres prepared under these conditions extended the presence of cephradin in the blood circulation up to 48 h. Increasing the load led to higher blood concentrations but shorter sustained release. The fact that the microspheres were for cattle limited the volume of the injection and thus the amount of microspheres to be administered. The other limiting factors were

  2. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    International Nuclear Information System (INIS)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao A.; Martinelli, Jose R.

    2011-01-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 ± 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  3. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia; Martinelli, Jose R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais

    2011-07-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 {+-} 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  4. Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui, E-mail: ghma@home.ipe.ac.cn; Su, Zhiguo

    2012-12-01

    Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate-divinylbezene) (PGMA-DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA-DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA-DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184 Degree-Sign to 13 Degree-Sign , and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: Black-Right-Pointing-Pointer Macroporous PGMA-DVB microspheres were covalently coated with dextran. Black-Right-Pointing-Pointer The hydrophilicity of the coated microspheres was significantly improved. Black-Right-Pointing-Pointer The irreversible adsorption of proteins was reduced to zero. Black-Right-Pointing-Pointer The coated microspheres can maintain the macropore structure. Black-Right-Pointing-Pointer The coated microspheres

  5. Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

    International Nuclear Information System (INIS)

    Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui; Su, Zhiguo

    2012-01-01

    Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate–divinylbezene) (PGMA–DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA–DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA–DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184° to 13°, and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: ► Macroporous PGMA–DVB microspheres were covalently coated with dextran. ► The hydrophilicity of the coated microspheres was significantly improved. ► The irreversible adsorption of proteins was reduced to zero. ► The coated microspheres can maintain the macropore structure. ► The coated microspheres were applied to rapid protein separation.

  6. Copper adsorption on magnetite-loaded chitosan microspheres: A kinetic and equilibrium study

    Energy Technology Data Exchange (ETDEWEB)

    Podzus, P.E., E-mail: ppodzus@gmail.com [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Debandi, M.V. [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Daraio, M.E., E-mail: medit@fi.uba.ar [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina)

    2012-08-15

    A composite of Fe{sub 3}O{sub 4} nanoparticles and the biopolymer chitosan, chemically crosslinked, was prepared as microspheres and used to adsorb copper ions, which were chosen as a model of contaminant metal in water. The adsorption of copper on the magnetic microspheres was studied in a batch process, with different aqueous solutions of Cu (II) at concentrations ranging from 40 to 1100 ppm. Kinetic and equilibrium aspects of the adsorption process were studied. The time-dependent Cu (II) adsorption data were well described by a pseudo-second-order kinetic model. It was found that the equilibrium data follow the Langmuir isotherm, with a maximum adsorption capacity of around 500 mg Cu/g chitosan. The used microspheres were removed and after desorption the material was able to be reused as an adsorbent. The prepared microspheres proved efficient in the removal of copper ions through an adsorption process whose kinetic and equilibrium characteristics were analyzed.

  7. Copper adsorption on magnetite-loaded chitosan microspheres: A kinetic and equilibrium study

    International Nuclear Information System (INIS)

    Podzus, P.E.; Debandi, M.V.; Daraio, M.E.

    2012-01-01

    A composite of Fe 3 O 4 nanoparticles and the biopolymer chitosan, chemically crosslinked, was prepared as microspheres and used to adsorb copper ions, which were chosen as a model of contaminant metal in water. The adsorption of copper on the magnetic microspheres was studied in a batch process, with different aqueous solutions of Cu (II) at concentrations ranging from 40 to 1100 ppm. Kinetic and equilibrium aspects of the adsorption process were studied. The time-dependent Cu (II) adsorption data were well described by a pseudo-second-order kinetic model. It was found that the equilibrium data follow the Langmuir isotherm, with a maximum adsorption capacity of around 500 mg Cu/g chitosan. The used microspheres were removed and after desorption the material was able to be reused as an adsorbent. The prepared microspheres proved efficient in the removal of copper ions through an adsorption process whose kinetic and equilibrium characteristics were analyzed.

  8. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate .... Oil-in-water emulsion was obtained by dispersing the organic phase .... tent is mainly due to the higher viscosity of the dispersed phase. Due to the ...

  9. Effect of crosslinking agents on chitosan microspheres in controlled release of diclofenac sodium

    OpenAIRE

    Gonçalves,Vanessa L.; Laranjeira,Mauro C. M.; Fávere,Valfredo T.; Pedrosa,Rozângela C.

    2005-01-01

    In this work chitosan microspheres were prepared by the simple coacervation method and crosslinked using epichlorhydrin or glutaraldehyde for the controlled release of diclofenac sodium. The effects of the crosslinking agents on chitosan microspheres over a 12-hour period were assessed with regard to swelling, hydrolysis, porosity, crosslinking, impregnation of diclofenac sodium (DS), and consequently to the release of DS in buffer solutions, simulating the gastrointestinal tract. The degree ...

  10. Transmission electron microscopy and Raman characterization of copper (I) oxide microspheres composed of nanoparticles

    International Nuclear Information System (INIS)

    Wang Wenzhong; Tu Ya; Wang Lijuan; Liang Yujie; Shi Honglong

    2013-01-01

    Highlights: ► Raman spectroscopy of copper (I) oxide microspheres were investigated. ► Infrared active mode is greatly activated in Raman scattering spectrum. ► Infrared active mode shows up in Raman spectrum of copper (I) oxide microspheres. ► The defects existed in spheres could be responsible for the observed Raman property. - Abstract: The high-resolution transmission electron microscope and Raman spectroscopy were used to investigate the microstructures and Raman scattering property of copper (I) oxide microspheres composed of nanoparticles. High-resolution transmission electron microscope images indicate that the copper (I) oxide microspheres are composed of nanoparticles with random growth direction, indicating that there are many defects in microspheres. The Raman spectrum shows that infrared active mode, which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is activated and shows up in Raman scattering spectrum. On the basis of investigations of the microstructure features of copper (I) oxide microspheres, we attribute the appearance of IR active mode in Raman scattering spectrum to the breakdown of the symmetry of the lattice due to the presence of defects in the prepared copper (I) oxide microspheres as observed in HRTEM images.

  11. 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.

  12. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  13. Controlled Release of Lysozyme from Double-Walled Poly(Lactide-Co-Glycolide (PLGA Microspheres

    Directory of Open Access Journals (Sweden)

    Rezaul H. Ansary

    2017-10-01

    Full Text Available Double-walled microspheres based on poly(lactide-co-glycolide (PLGA are potential delivery systems for reducing a very high initial burst release of encapsulated protein and peptide drugs. In this study, double-walled microspheres made of glucose core, hydroxyl-terminated poly(lactide-co-glycolide (Glu-PLGA, and carboxyl-terminated PLGA were fabricated using a modified water-in-oil-in-oil-in-water (w1/o/o/w2 emulsion solvent evaporation technique for the controlled release of a model protein, lysozyme. Microspheres size, morphology, encapsulation efficiency, lysozyme in vitro release profiles, bioactivity, and structural integrity, were evaluated. Scanning electron microscopy (SEM images revealed that double-walled microspheres comprising of Glu-PLGA and PLGA with a mass ratio of 1:1 have a spherical shape and smooth surfaces. A statistically significant increase in the encapsulation efficiency (82.52% ± 3.28% was achieved when 1% (w/v polyvinyl alcohol (PVA and 2.5% (w/v trehalose were incorporated in the internal and external aqueous phase, respectively, during emulsification. Double-walled microspheres prepared together with excipients (PVA and trehalose showed a better control release of lysozyme. The released lysozyme was fully bioactive, and its structural integrity was slightly affected during microspheres fabrication and in vitro release studies. Therefore, double-walled microspheres made of Glu-PLGA and PLGA together with excipients (PVA and trehalose provide a controlled and sustained release for lysozyme.

  14. Produção e utilização de gotas com diâmetro uniforme The generation and use of uniformly sized droplets

    Directory of Open Access Journals (Sweden)

    Hermes Geraldo Corrêa

    1982-01-01

    Full Text Available A execução da pesquisa com freqüência requer o desenvolvimento de aparelhagem específica. Para estudo dos parâmetros das populações de gotas produzidas por pulverizadores é necessário conhecer o fator de espalhamento de diversas formulações sobre superfícies de amostragem (papel kromekote, melamina (fórmica, vidro etc.. Essa determinação requer aparelhagem geradora de gotas com diâmetro uniforme. Com este objetivo principal, realizou-se o presente trabalho. Além de sua utilização para investigar o comportamento físico da pulverização, o aparelho poderá ter outras aplicações no campo da biologia, como a distribuição uniforme de esporos em dose determinada sobre superfícies vegetais, permitindo, também, observações sobre o efeito tóxico de determinadas doses de defensivos sobre vegetais e animais. O aparelho produziu gotas com diâmetro que, em média, apresentaram coeficiente de variação de 2,36%. o fator de espalhamento para solução aquosa de rodamina a 0,2% sobre papel kromekote apresentou a variação de 1,32 a 1,71 quando se usaram, respectivamente, gotas entre 98 e 325 micra. Para Malathion a 96% de principio ativo, sobre papel kromekote, as gotículas apresentaram fatores de espalhamento variando de 4,09 a 5,18 quando se utilizaram gotas entre 80 e 217 micra. A melamina branca (fórmica apresentou menores variações nesse fator quando lhe foi aplicado o Malathion.This paper deals with the construction and use of a spinning disc atomizer that produces uniformly sized droplets. The device has a special use in the determination of the spread factor on several sampling surfaces (Kromekote paper, glass, plastic etc.. Furthermore, it permits the study of spraying performance, the inoculation of known spore doses of fungi and observations about toxical effects of pesticides on vegetables and animals. The apparatus showed a narrow droplet size spectrum, with a coefficient of variation about 2.36%. The spread

  15. Storage stability of biodegradable polyethylene glycol microspheres

    Science.gov (United States)

    Jain, Era; Sheth, Saahil; Polito, Kristen; Sell, Scott A.; Zustiak, Silviya P.

    2017-10-01

    Degradable hydrogel microspheres are popular choices for multiple biomedical applications, including drug, protein, or cell carriers for minimally invasive delivery. Clinical transitioning of such new, sensitive pharmaceutical preparations requires investigation of storage methods that retain key properties for extended time. In this study, we sought to determine the influence of seven common storage conditions on the physical and mechanical properties of degradable polyethylene glycol (PEG) hydrogel microspheres: 25 °C, 4 °C, -80 °C, lyophilization/-20 °C, dimethyl sulfoxide/-80 °C, dimethyl sulfoxide/lyophilization/-20 °C, vacuum/-20 °C. We have outlined the storage conditions in detail and explained their effect on swelling ratio, stiffness and degradation rate post-storage. Additionally, we have implemented protein-loaded hydrogels to evaluate the effect of storage conditions on diffusivity as well as protein stability post-storage. We found that hydrogels could be stored short-term (1-4 d) under moist conditions (i.e. storage without drying) without a substantial loss of properties. For extended storage (7-28 d), they could be stored either at  -80 °C (moist condition) or vacuum drying (dry condition).

  16. Occupational radiation exposure of medical staff performing 90Y-loaded microsphere radioembolization

    International Nuclear Information System (INIS)

    Laffont, Sophie; Ardisson, Valerie; Lenoir, Laurence; Rolland, Yan; Rohou, Tanguy; Edeline, Julien; Pracht, Marc; Sourd, Samuel Le; Lepareur, Nicolas; Garin, Etienne

    2016-01-01

    Radioembolization of liver cancer with 90 Y-loaded microspheres is increasingly used but data regarding hospital staff exposure are scarce. We evaluated the radiation exposure of medical staff while preparing and injecting 90 Y-loaded glass and resin microspheres especially in view of the increasing use of these products. Exposure of the chest and finger of the radiopharmacist, nuclear medicine physician and interventional radiologist during preparation and injection of 78 glass microsphere preparations and 16 resin microsphere preparations was monitored. Electronic dosimeters were used to measure chest exposure and ring dosimeters were used to measure finger exposure. Chest exposure was very low for both products used (<10 μSv from preparation and injection). In our experience, finger exposure was significantly lower than the annual limit of 500 mSv for both products. With glass microspheres, the mean finger exposure was 13.7 ± 5.2 μSv/GBq for the radiopharmacist, and initially 17.9 ± 5.4 μSv/GBq for the nuclear medicine physician reducing to 13.97 ± 7.9 μSv/GBq with increasing experience. With resin microspheres, finger exposure was more significant: mean finger exposure for the radiopharmacist was 295.1 ± 271.9 μSv/GBq but with a reduction with increasing experience to 97.5 ± 35.2 μSv/GBq for the six most recent dose preparations. For administration of resin microspheres, the greatest mean finger exposure for the nuclear medicine physician (the most exposed operator) was 235.5 ± 156 μSv/GBq. Medical staff performing 90 Y-loaded microsphere radioembolization procedures are exposed to safe levels of radiation. Exposure is lower than that from treatments using 131 I-lipiodol. The lowest finger exposure is from glass microspheres. With resin microspheres finger exposure is acceptable but could be optimized in accordance with the ALARA principle, and especially in view of the increasing use of radioembolization. (orig.)

  17. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    farquar, G; Leif, R

    2008-09-12

    Biocompatible polymers with hydrolyzable chemical bonds are being 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 are being 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. The advantages and disadvantages of each method will be presented and discussed in greater detail along with fluorescent and charge properties of the aerosols. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  18. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    International Nuclear Information System (INIS)

    Cao Feng; Li Dongxu

    2010-01-01

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe 3+ , which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  19. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao Feng; Li Dongxu, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

    2010-03-15

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe{sup 3+}, which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  20. Mucoadhesive microspheres: a promising tool in drug delivery.

    Science.gov (United States)

    Patil, Sanjay B; Sawant, Krutika K

    2008-10-01

    Mucoadhesive polymers have recently gained interest among pharmaceutical scientists as a means of improving drug delivery by promoting the residence time and contact time of the dosage form with the mucous membranes. Mucoadhesion is the process whereby synthetic and natural polymers adhere to mucosal surfaces in the body. If these materials are then incorporated into pharmaceutical formulations, drug absorption by mucosal cells may be enhanced or the drug will be released at the site for an extended period of time. Microspheres, in general, have the potential to be used for targeted and controlled release drug delivery; however, coupling of mucoadhesive properties to microspheres has additional advantages like, a much more intimate contact with the mucus layer, efficient absorption and enhanced bioavailability of the drugs due to a high surface to volume ratio. The present review describes the potential applications of mucoadhesive microspheres as a novel carrier system to improve drug delivery by various routes of administration like buccal, oral, nasal, ocular, vaginal and rectal, either for systemic or for local effects. The mucoadhesive polymers, methods of preparation of microspheres and their in vitro and in vivo evaluation are also described.

  1. 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.

  2. Polyacrylate microspheres composite for all-solid-state reference electrodes.

    Science.gov (United States)

    Kisiel, Anna; Donten, Mikołaj; Mieczkowski, Józef; Rius-Ruiz, F Xavier; Maksymiuk, Krzysztof; Michalska, Agata

    2010-09-01

    A novel concept is proposed for the encapsulation of components within polyacrylate microspheres, prior to their incorporation into a membrane phase. Thus finer and better controlled dispersion of heterogeneous membrane components can be achieved. This concept was verified by using a poly(n-butyl acrylate) membrane-based reference electrode as an example. In this example the proper dispersion of solid constituents of the heterogeneous membrane and prevention of their leakage are both of primary importance. Potassium chloride-loaded poly(n-butyl acrylate) microspheres were prepared and then left in contact with silver nitrate to convert some of the KCl into AgCl. The material obtained was introduced into a poly(n-butyl acrylate) membrane. The reference electrode membranes obtained in this way were characterized with much more stable potential (both in different electrolytes and over time) compared with electrodes prepared by the direct introduction of KCl and AgCl to the membrane.

  3. Coherent inflation for large quantum superpositions of levitated microspheres

    Science.gov (United States)

    Romero-Isart, Oriol

    2017-12-01

    We show that coherent inflation (CI), namely quantum dynamics generated by inverted conservative potentials acting on the center of mass of a massive object, is an enabling tool to prepare large spatial quantum superpositions in a double-slit experiment. Combined with cryogenic, extreme high vacuum, and low-vibration environments, we argue that it is experimentally feasible to exploit CI to prepare the center of mass of a micrometer-sized object in a spatial quantum superposition comparable to its size. In such a hitherto unexplored parameter regime gravitationally-induced decoherence could be unambiguously falsified. We present a protocol to implement CI in a double-slit experiment by letting a levitated microsphere traverse a static potential landscape. Such a protocol could be experimentally implemented with an all-magnetic scheme using superconducting microspheres.

  4. Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Katalenich; Michael R. Hartman; Robert C. O' Brien

    2013-02-01

    Cerium oxide and uranium oxide microspheres are being produced via an internal gelation sol-gel method to investigate alternative fabrication routes for space nuclear fuels. Depleted uranium and non-radioactive cerium are being utilized as surrogates for plutonium-238 (Pu-238) used in radioisotope thermoelectric generators and for enriched uranium required by nuclear thermal rockets. While current methods used to produce Pu-238 fuels at Los Alamos National Laboratory (LANL) involve the generation of fine powders that pose a respiratory hazard and have a propensity to contaminate glove boxes, the sol-gel route allows for the generation of oxide microsphere fuels through an aqueous route. The sol-gel method does not generate fine powders and may require fewer processing steps than the LANL method with less operator handling. High-quality cerium dioxide microspheres have been fabricated in the desired size range and equipment is being prepared to establish a uranium dioxide microsphere production capability.

  5. In-vitro studies of enteric coated diclofenac sodium-carboxymethylcellulose microspheres.

    Science.gov (United States)

    Arica, B; Arica, M Y; Kaş, H S; Hincal, A A; Hasirci, V

    1996-01-01

    MIcrospheres containing diclofenac sodium (DS) were prepared using carboxymethylcellulose (CMC) as the main support material (1.0, 2.0, 3.0% (w/v)) and aluminum chloride as the crosslinker. Drug to polymer ratios of 1:1, 1:2 and 1:4 were used to obtain a range of microspheres. The microspheres were then coated with an enteric coating material, Eudragit S-100, efficiency, % yield value, particle sizes an in-vitro dissolution behaviour were investigated. The surface of the enteric coated microspheres seemed to be all covered with Eudragit S-100 from scanning electron microscopy observation. It was also observed that increasing the CMC concentration led to an increase in the encapsulation efficiency, % yield value and particle size and decreased the release rate. Eudragit S-100 coating did not significantly alter the size but the release rate was significantly lower even when the lower concentration solution was used.

  6. Effect of crosslinking agents on chitosan microspheres in controlled release of diclofenac sodium

    Directory of Open Access Journals (Sweden)

    Vanessa L. Gonçalves

    2005-03-01

    Full Text Available In this work chitosan microspheres were prepared by the simple coacervation method and crosslinked using epichlorhydrin or glutaraldehyde for the controlled release of diclofenac sodium. The effects of the crosslinking agents on chitosan microspheres over a 12-hour period were assessed with regard to swelling, hydrolysis, porosity, crosslinking, impregnation of diclofenac sodium (DS, and consequently to the release of DS in buffer solutions, simulating the gastrointestinal tract. The degree of swelling varied with the pH for glutaraldehyde chitosan microspheres (GCM and epichlorhydrin chitosan microspheres (ECM. Partial acid and basic hydrolysis affected the swelling behavior of the GCM matrix. Release kinetics of diclofenac sodium from these matrices were investigated at pH 1.2, 6.8 and 9.0, simulating the gastrointestinal tract conditions. The results indicated that the release mechanism deviated slightly from Fickian transport.

  7. Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells

    Energy Technology Data Exchange (ETDEWEB)

    Chung, T.-H.; Chang, J.-Y. [Department of Chemical Engineering, National Chung Cheng University, Chiayi 621, Taiwan (China); Lee, W.-C. [Department of Chemical Engineering, National Chung Cheng University, Chiayi 621, Taiwan (China)], E-mail: chmwcl@ccu.edu.tw

    2009-05-15

    Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1{sup +} cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1{sup +} cells corresponding to a 17-fold enrichment was achieved.

  8. Ketoprofen-loaded Eudragit RSPO microspheres: an influence of sodium carbonate on in vitro drug release and surface topology.

    Science.gov (United States)

    Pandit, Sachin S; Hase, Dinesh P; Bankar, Manish M; Patil, Arun T; Gaikwad, Naresh J

    2009-05-01

    Eudragit RSPO microspheres containing ketoprofen as model drug, prepared by solvent evaporation technique using acetone-liquid paraffin (heavy) solvent system were examined. Depending upon polymer concentration in the internal phase, microspheres of particle mean diameter (122.8, 213.6 and 309.5 μm) were obtained. The influence of surface washing of microspheres with n-hexane, i.e. untreated microspheres (UM) on the drug content, drug release and surface topology of microspheres were compared to those of microspheres washed with sodium carbonate, i.e. treated microspheres (TM) in order to make the non-encapsulated surface drug soluble. The significant reduction in encapsulation efficiency (p < 0.001) and drug content (p < 0.001) after treatment, in combination with the small crystalline peaks observed during XRD testing and lack of melting endotherm observed in DSC testing, suggests that the washing process actually removes a significant amount of drug (p < 0.001) from the surface and encapsulated near to the surface of the microsphere polymer matrix. Scanning electron microscopy (SEM) examination revealed that the removal of surface drug did not affect the size of microspheres but the topology of treated smallest microspheres was modified. The ketoprofen release profiles were examined in phosphate buffer pH 7.4, using USPXXIII paddle type dissolution apparatus. In general both UM and TM result in biphasic release patterns, but the initial burst effect (first release phase) of TM was lower than that of UM. The second release phase did not change for the bigger size but increased for the smallest microspheres, probably owing to the modification of matrix porosity.

  9. Synthesis of Hollow CdS-TiO2 Microspheres with Enhanced Visible-Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yuning Huo

    2012-01-01

    Full Text Available CdS-TiO2 composite photocatalyst in the shape of hollow microsphere was successfully synthesized via the hard-template preparation with polystyrene microspheres followed by ion-exchange approach. The hollow CdS-TiO2 microspheres significantly extended the light adsorption into visible light region, comparing to TiO2 microspheres. It led to much higher photocatalytic activities of hollow CdS-TiO2 microspheres than that of TiO2 during the photodegradation of rhodamine B under visible light irradiations. Furthermore, the well-remained hollow structure could achieve light multireflection within the interior cavities and the separation of photo-induced electrons and holes is efficient in CdS-TiO2, which were facilitated to improving the photoactivity.

  10. Synthesis of Poly(Ortho-Phenylenediamine) Fluffy Microspheres and Application for the Removal of Cr(VI)

    International Nuclear Information System (INIS)

    Wang, Z.; Liao, F.

    2012-01-01

    We reported the synthesis of fluffy poly(o-phenylenediamine) (PoPD) microspheres via chemical polymerization of PoPD monomers by ammonium persulfate (APS) at room temperature. The SEM images showed that PoPD microspheres with an average diameter of 1.5 μm and their surfaces consist of highly oriented nano fibers. Furthermore, PoPD microspheres were used as adsorbent materials for the removal of Cr(VI) from aqueous solutions. The Cr(VI) adsorption behavior on the prepared PoPD microspheres was studied at different adsorption contact times, solution ph values, and amount of the adsorbent. Experimental isotherms of Cr(VI) ions were successfully fit to the Langmuir isotherm model. The results indicate that the PoPD fluffy microspheres are an effective adsorbent for the removal of Cr(VI) ions from aqueous solutions, and they could be useful in treatment of Cr(VI)-polluted wastewaters.

  11. Fabrication of Alkoxyamine-Functionalized Magnetic Core-Shell Microspheres via Reflux Precipitation Polymerization for Glycopeptide Enrichment

    Directory of Open Access Journals (Sweden)

    Meng Yu

    2016-03-01

    Full Text Available As a facile method to prepare hydrophilic polymeric microspheres, reflux precipitation polymerization has been widely used for preparation of polymer nanogels. In this article, we synthesized a phthalamide-protected N-aminooxy methyl acrylamide (NAMAm-p for preparation of alkoxyamine-functionalized polymer composite microspheres via reflux precipitation polymerization. The particle size and functional group density of the composite microspheres could be adjusted by copolymerization with the second monomers, N-isopropyl acrylamide, acrylic acid or 2-hydroxyethyl methacrylate. The resultant microspheres have been characterized by TEM, FT-IR, TGA and DLS. The experimental results showed that the alkoxyamine group density of the microspheres could reach as high as 1.49 mmol/g, and these groups showed a great reactivity with ketone/aldehyde compounds. With the aid of magnetic core, the hybrid microspheres could capture and magnetically isolate glycopeptides from the digested mixture of glycopeptides and non-glycopeptides at a 1:100 molar ratio. After that, we applied the composite microspheres to profile the glycol-proteome of a normal human serum sample, 95 unique glycopeptides and 64 glycoproteins were identified with these enrichment substrates in a 5 μL of serum sample.

  12. Hierarchical CuO hollow microspheres: Controlled synthesis for enhanced lithium storage performance

    International Nuclear Information System (INIS)

    Guan Xiangfeng; Li Liping; Li Guangshe; Fu Zhengwei; Zheng Jing; Yan Tingjiang

    2011-01-01

    Graphical abstract: Hierarchical CuO microspheres with hollow interiors were formed through self-wrapping of a single layer of radically oriented CuO nanorods, and these microspheres showed excellent cycle performance and enhanced lithium storage capacity. Display Omitted Research highlights: → Hierarchical CuO hollow microspheres were prepared by a hydrothermal method. → The CuO hollow microspheres were assembled from radically oriented nanorods. → The growth mechanism was proposed to proceed via self-assembly and Ostwald's ripening. → The microspheres showed good cycle performance and enhanced lithium storage capacity. → Hierarchical microstructures with hollow interiors promote electrochemical property. - Abstract: In this work, hierarchical CuO hollow microspheres were hydrothermally prepared without use of any surfactants or templates. By controlling the formation reaction conditions and monitoring the relevant reaction processes using time-dependent experiments, it is demonstrated that hierarchical CuO microspheres with hollow interiors were formed through self-wrapping of a single layer of radically oriented CuO nanorods, and that hierarchical spheres could be tuned to show different morphologies and microstructures. As a consequence, the formation mechanism was proposed to proceed via a combined process of self-assembly and Ostwald's ripening. Further, these hollow microspheres were initiated as the anode material in lithium ion batteries, which showed excellent cycle performance and enhanced lithium storage capacity, most likely because of the synergetic effect of small diffusion lengths in building blocks of nanorods and proper void space that buffers the volume expansion. The strategy reported in this work is reproducible, which may help to significantly improve the electrochemical performance of transition metal oxide-based anode materials via designing the hollow structures necessary for developing lithium ion batteries and the relevant

  13. Improvements in processing characteristics and engineering properties of wood flour-filled high density polyethylene composite sheeting in the presence of hollow glass microspheres

    Science.gov (United States)

    Baris Yalcin; Steve E Amos; Andrew S D Souza; Craig M Clemons; I Sedat Gunes; Troy K Ista

    2012-01-01

    Hollow glass microspheres were introduced into wood flour/high density polyethylene composites by melt compounding in a twin-screw extruder. The prepared composites were subsequently converted to extruded profiles in order to obtain composite sheeting. The presence of hollow glass microspheres highly reduced the density of the extruded sheets down to 0.9 g/cc, while...

  14. Chitosan microspheres in novel drug delivery systems.

    Science.gov (United States)

    Mitra, Analava; Dey, Baishakhi

    2011-07-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

  15. Synthesis, characterization, and photocatalytic properties of Ni12P5 hollow microspheres

    Science.gov (United States)

    Liu, Shuling; Han, Xiaoli; Zhang, Hongzhe; Liu, Hui

    2017-05-01

    Ni12P5 hollow microspheres were prepared by a simple mixed cetyltrimethyl ammonium bromide/sodium dodecyl sulfate surfactant-assisted hydrothermal route. The as-prepared Ni12P5 microstructures were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). It was interesting to find that cetyltrimethyl ammonium bromide/sodium dodecyl sulfate could form a micro-reactor by the mixed micelles in the aqueous solution, which served as a soft template for Ni12P5 hollow microspheres with a diameter of 2 6 μm. Moreover, the as-prepared Ni12P5 hollow microspheres exhibited a good photocatalytic degradation activity for some organic dyes (such as Rhodamine B, Methylene Blue, Pyronine B, and Safranine T), and the degradation ratio could achieve more than 80%.

  16. Development and gamma-scintigraphy study of Hibiscus rosasinensis polysaccharide-based microspheres for nasal drug delivery.

    Science.gov (United States)

    Sharma, Nitin; Tyagi, Shanu; Gupta, Satish Kumar; Kulkarni, Giriraj Thirupathirao; Bhatnagar, Aseem; Kumar, Neeraj

    2016-11-01

    This work describes the application of natural plant polysaccharide as pharmaceutical mucoadhesive excipients in delivery systems to reduce the clearance rate through nasal cavity. Novel natural polysaccharide (Hibiscus rosasinensis)-based mucoadhesive microspheres were prepared by using emulsion crosslinking method for the delivery of rizatriptan benzoate (RB) through nasal route. Mucoadhesive microspheres were characterized for different parameters and nasal clearance of technetium-99m ((99m)Tc)-radiolabeled microspheres was determined by using gamma-scintigraphy. Their Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies showed that the drug was stable during preparation of microspheres. Aerodynamic diameter of microspheres was in the range 13.23 ± 1.83-33.57 ± 3.69 µm. Change in drug and polysaccharide ratio influenced the mucoadhesion, encapsulation efficiency and in-vitro release property. Scintigraphs taken at regular interval indicate that control solution was cleared rapidly from nasal cavity, whereas microspheres showed slower clearance (p < 0.005) with half-life of 160 min. Natural polysaccharide-based microspheres achieved extended residence by minimizing effect of mucociliary clearance with opportunity of sustained delivery for longer duration.

  17. Development and in vitro evaluation of diclofenac sodium loaded mucoadhesive microsphere with natural gum for sustained delivery.

    Science.gov (United States)

    Amin, Md Lutful; Jesmeen, Tasbira; Sutradhar, Kumar Bishwajit; Mannan, Md Abdul

    2013-12-01

    The objective of this study was to develop and evaluate mucoadhesive microsphere of diclofenac sodium with natural gums for sustained delivery. Guar gum and tragacanth were used along with sodium alginate as mucoadhesive polymers. Microspheres were formulated using orifice-ionic gelation method. Particle size, surface morphology, swelling study and drug entrapment efficiency of the prepared microspheres were determined. In vitro evaluation was carried out comprising of mucoadhesion and drug release study. The prepared microspheres were discrete and free flowing. Sodium alginate and natural gum, at a ratio of 1:0.25, showed good mucoadhesive property and they had high drug entrapment efficiencies. They also exhibited the best rate retarding effect among all the formulations. Drug entrapment efficiency of all the microspheres ranged from 80.42% to 91.67%. An inverse relationship was found between extent of crosslinking and drug release rate. Release rate was slow and extended in case of the formulations of 1:0.25 ratio (F1 and F3), releasing 68.36% and 70.56% drug respectively after 8 hours. Tragacanth-containing microspheres of F1 showed superiority over other formulations, with best mucoadhesive and rate retarding profile. The correlation value (r(2)) indicated that the drug release of all the formulations followed Higuchi's model. Overall, the results indicated that mucoadhesive microspheres containing natural gum can be promising in terms of prolonged delivery with good mucoadhesive action, targeting the absorption site to thrive oral drug delivery.

  18. Biomimetic mineralization of calcium carbonate/carboxymethylcellulose microspheres for lysozyme immobilization

    International Nuclear Information System (INIS)

    Lu Zheng; Zhang Juan; Ma Yunzi; Song Siyue; Gu Wei

    2012-01-01

    Porous calcium carbonate/carboxymethylcellulose (CaCO 3 /CMC) microspheres were prepared by the biomimetic mineralization method for lysozyme immobilization via adsorption. The size and morphology of CaCO 3 /CMC microspheres were characterized by transmitted electron microscopy (TEM) and zeta potential measurement. The lysozyme immobilization was verified by Fourier transform infrared (FTIR) spectroscopy. The effects of pHs and temperatures on lysozyme adsorption were investigated as well. It was revealed that CaCO 3 /CMC microspheres could immobilize lysozyme efficiently via electrostatic interactions and a maximum adsorption capacity of 450 mg/g was achieved at pH 9.2 and 25 °C. Moreover, it was found that the adsorption process fitted well with the Langmuir isothermal model. In addition, UV, fluorescence, and circular dichroism (CD) spectroscopic studies showed that lysozyme maintained its original secondary structure during the adsorption/desorption process. Our study therefore demonstrated that CaCO 3 /CMC microsphere can be used as a cost-effective and efficient support for lysozyme immobilization. - Graphical abstract: CaCO 3 /CMC microsphere was prepared by a facile biomimetic mineralization method and can be used as an efficient and cost-effective support for lysozyme immobilization. Highlights: ► CaCO 3 /CMC microspheres were prepared by the biomimetic mineralization method. ► Lysozyme was efficiently immobilized to CaCO 3 /CMC microspheres via adsorption. ► A maximum adsorption capacity of 450 mg/g was obtained at pH 9.2 and 25 °C. ► The original secondary structure of lysozyme was maintained upon immobilization.

  19. 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.

  20. Evaluation of the Thermosensitive Release Properties of Microspheres Containing an Agrochemical Compound.

    Science.gov (United States)

    Terada, Takatoshi; Ohtsubo, Toshiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2017-01-01

    The purpose of this study was to develop a deeper understanding of the key physicochemical parameters involved in the release profiles of microsphere-encapsulated agrochemicals at different temperatures. Microspheres consisting of different polyurethanes (PUs) were prepared using our previously reported solventless microencapsulation technique. Notably, these microspheres exhibited considerable differences in their thermodynamic characteristics, including their glass transition temperature (T g ), extrapolated onset temperature (T o ) and extrapolated end temperature (T e ). At test temperatures below the T o of the PU, only 5-10% of the agrochemical was rapidly released from the microspheres within 1 d, and none was released thereafter. However, at test temperatures above the T o of the PU, the rate of agrochemical release gradually increased with increasing temperatures, and the rate of release from the microspheres was dependent on the composition of the PU. Taken together, these results show that the release profiles of the microspheres were dependent on their thermodynamic characteristics and changes in their PU composition.

  1. Effect of gamma-irradiation on biodegradable microspheres loaded with rasagiline mesylate

    International Nuclear Information System (INIS)

    Fernandez, Marcos; Barcia, Emilia; Negro, Sofia

    2016-01-01

    In the present study, the influence of gamma-irradiation was evaluated on the physicochemical characteristics and in vitro release of rasagiline mesylate (RM), a selective MAO-B inhibitor used in Parkinson's disease, from poly(D,L-lactide-co-glycolide) (PLGA) microspheres. Microspheres were prepared using PLGA 50:50 by the solvent evaporation technique (O/W emulsion). Microspheres were sterilized by gamma-irradiation and their influence was assessed by scanning electron microscopy (SEM), laser light diffraction, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeation chromatography (GPC), encapsulation efficiency (EE) and in vitro drug release. Gamma-irradiation of RM-loaded microspheres did not affect EE, DSC and XRD patterns. After gamma-irradiation, changes on the surface were observed by SEM, but no significant difference in mean particle size was observed. GPC measurements showed a decrease in molecular weight of the polymer after five days of in vitro release. The similarity factor value between irradiated and non-irradiates microspheres was <50, indicating the non-similarity of the release profiles. The sterilization technique had an effect on the integrity of polymeric system, significantly affecting in vitro release of RM from PLGA microspheres. Therefore, from our results we conclude that gamma-irradiation is not a suitable sterilization procedure for this formulation

  2. Properties of Amorphous Carbon Microspheres Synthesised by Palm Oil-CVD Method

    International Nuclear Information System (INIS)

    Zobir, S. A. M.; Zainal, Z.; Sarijo, S. H.; Rusop, M.

    2011-01-01

    Amorphous carbon microspheres were synthesized using a dual-furnace chemical vapour deposition method at 800-1000 deg. C. Palm oil-based cooking oil (PO) and zinc nitrate solution was used as a carbon source and catalyst precursor, respectively with PO to zinc nitrate ratio of 30:20 (v/v) and a silicon wafer as the sample target. Regular microsphere shape of the amorphous carbons was obtained and a uniform microsphere structure improved as the carbonization temperature increased from 800 to 1000 deg. C. At 800 deg. C, no regular microspheres were formed but more uniform structure is observed at 900 deg. C. Generally the microspheres size is uniform when the heating temperature was increased to 1000 deg. C, but the presence of mixed sizes can still be observed. X-ray diffraction patterns show the presence of oxide of carbon, ZnO phase together with Zn oxalate phase. Raman spectra show two broad peaks characteristic to amorphous carbon at 1344 and 1582 cm -1 for the D and G bands, respectively. These bands become more prominent as the preparation temperature increased from 800 to 1000 deg. C. This is in agreement with the formation of amorphous carbon microspheres as shown by the FESEM study and other Zn-based phases as a result of the oxidation process of the palm oil as the carbon source and the zinc nitrate as the catalyst precursor, respectively.

  3. Production of cerium dioxide microspheres by an internal gelation sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Katalenich, Jeffrey A.

    2017-03-27

    An internal gelation sol-gel technique was used to prepare cerium dioxide microspheres with uniform diameters near 100 µm. In this process, chilled aqueous solutions containing cerium, hexamethylenetetramine (HMTA), and urea are transformed into a solid gel by heat addition and are subsequently washed, dried, and sintered to produce pure cerium dioxide. Cerous nitrate and ceric ammonium nitrate solutions were compared for their usefulness in microsphere production. Gelation experiments were performed with both cerous nitrate and ceric ammonium nitrate to determine desirable concentrations of cerium, HMTA, and urea in feed solutions as well as the necessary quantity of ammonium hydroxide added to cerium solutions. Analysis of the pH before and after sample gelation was found to provide a quantitative metric for optimal parameter selection along with subjective evaluations of gel qualities. The time necessary for chilled solutions to gel upon inserting into a hot water bath was determined for samples with a variety of parameters and also used to determine desirable formulations for microsphere production. A technique for choosing the optimal mixture of ceric ammonium nitrate, HMTA, and urea was determined using gelation experiments and used to produce microspheres by dispersion of the feed solution into heated silicone oil. Gelled spheres were washed to remove excess reactants and reaction products before being dried and sintered. X-ray diffraction of air-dried microspheres, sintered microspheres, and commercial CeO2 powders indicated that air-dried and sintered spheres were pure CeO2.

  4. Diclofenac salts, part 6: release from lipid microspheres.

    Science.gov (United States)

    Fini, Adamo; Cavallari, Cristina; Rabasco Alvarez, Antonio M; Rodriguez, Marisa Gonzalez

    2011-08-01

    The release of diclofenac (20%, w/w) was studied from lipidic solid dispersions using three different chemical forms (acid, sodium salt, and pyrrolidine ethanol salt) and two different lipid carriers (Compritol 888 ATO or Carnauba wax) either free or together with varying amounts (10%-30%, w/w) of stearic acid. Microspheres were prepared by ultrasound-assisted atomization of the molten dispersions and analyzed by scanning electron microscopy, differential scanning calorimetry, and hot stage microscopy. The effects of different formulations on the resulting drug release profiles as a function of pH were studied and the results were discussed. The formulation of the 18 systems and the chemical form of the drug were found to strongly affect the mode of the drug release. The solubility of the chemical forms in the lipid mixture is in the following order: pyrrolidine ethanol salt ≫ acid > sodium salt (according to the solubility parameters), and the nature of the systems thus obtained ranges from a matrix, for mutually soluble drug/carrier pairs, to a microcapsule, for pairs wherein mutual solubility is poor. Drug release from microspheres prepared by pure lipids was primarily controlled by diffusion, whereas the release from microspheres containing stearic acid was diffusion/erosion controlled at pH 7.4. Copyright © 2011 Wiley-Liss, Inc.

  5. Synthesis of microspheres of triuranium octaoxide by simultaneous water and nitrate extraction from ascorbate-uranyl sols.

    Science.gov (United States)

    Brykala, M; Deptula, A; Rogowski, M; Lada, W; Olczak, T; Wawszczak, D; Smolinski, T; Wojtowicz, P; Modolo, G

    A new method for synthesis of uranium oxide microspheres (diameter nitrate-ascorbate sols were prepared by addition of ascorbic acid to uranyl nitrate hexahydrate solution and alkalizing by aqueous ammonium hydroxide and then emulsified in 2-ethylhexanol-1 containing 1v/o SPAN-80. Drops of emulsion were firstly gelled by extraction of water by the solvent. Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem. Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.

  6. Mucoadhesive microspheres for gastroretentive delivery of acyclovir: in vitro and in vivo evaluation.

    Science.gov (United States)

    Dhaliwal, Sumeet; Jain, Subheet; Singh, Hardevinder P; Tiwary, A K

    2008-06-01

    The aim of the present investigation was to evaluate the potential use of mucoadhesive microspheres for gastroretentive delivery of acyclovir. Chitosan, thiolated chitosan, Carbopol 71G and Methocel K15M were used as mucoadhesive polymers. Microsphere formulations were prepared using emulsion-chemical crosslinking technique and evaluated in vitro, ex-vivo and in-vivo. Gelatin capsules containing drug powder showed complete dissolution (90.5 +/- 3.6%) in 1 h. The release of drug was prolonged to 12 h (78.8 +/- 3.9) when incorporated into mucoadhesive microspheres. The poor bioavailability of acyclovir is attributed to short retention of its dosage form at the absorption sites (in upper gastrointestinal tract to duodenum and jejunum). The results of mucoadhesion study showed better retention of thiolated chitosan microspheres (8.0 +/- 0.8 h) in duodenal and jejunum regions of intestine. The results of qualitative and quantitative GI distribution study also showed significant higher retention of mucoadhesive microspheres in upper GI tract. Pharmacokinetic study revealed that administration of mucoadhesive microspheres could maintain measurable plasma concentration of acyclovir through 24 h, as compared to 5 h after its administration in solution form. Thiolated chitosan microsphere showed superiority over the other formulations as observed with nearly 4.0-fold higher AUC(0-24) value (1,090 +/- 51 ng h/ml) in comparison to drug solution (281 +/- 28 ng h/ml). Overall, the result indicated prolonged delivery with significant improvement in oral bioavailability of acyclovir from mucoadhesive microspheres due to enhanced retention in the upper GI tract.

  7. Development and evaluation of intestinal targeted mucoadhesive microspheres of Bacillus coagulans.

    Science.gov (United States)

    Alli, Sk Md Athar; Ali, Sk Md Ajhar; Samanta, Amalesh

    2011-11-01

    Intestinal targeted mucoadhesive microsphere of probiotics may provide numerous associated health benefits. To develop mucoadhesive microspheres that will deliver viable probiotic cells into gut protectively against harsh environmental conditions of stomach for extended period. Core mucoadhesive microspheres of Bacillus coagulans were prepared using hypromellose, following coacervation and phase separation technique and were then coated with hypromellose phthalate to achieve their site-specific release. Microspheres were evaluated for percent yield, entrapment efficiency, surface morphology, particle size and size distribution, flow property, swelling property, mucoadhesion property by the in vitro wash-off and the ex vivo mucoadhesive strength tests, in vitro release profile and release kinetic, in vivo probiotic activity, and stability. The values for kinetic constant and regression coefficient of model-dependent approaches and the difference factor, the similarity factor, and the Rescigno index of model-independent approaches were determined for accessing and comparing in vitro performance. Microsphere formulation batches have percent yield value between 56.26% and 69.13% and entrapment efficiency value between 66.95% and 77.89%. Microspheres were coarser with spherical shape having mean particle size from 28.03 to 48.31 μm. In vitro B. coagulans release profile follows zero-order kinetics and depends on the grade of hypromellose and the B. coagulans-to-hypromellose ratio. Experimental microspheres rendered adequate stability to B. coagulans at room temperature. Microspheres had delivered B. coagulans in simulated intestinal condition following zero-order kinetics, protectively in simulated gastric condition, exhibiting appreciable mucoadhesion in intestinal condition, which could be useful to achieve site-specific delivery for extended period.

  8. 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.

  9. Onion-like microspheres with tricomponent from gelable triblock copolymers.

    Science.gov (United States)

    Zhang, Ke; Gao, Lei; Chen, Yongming; Yang, Zhenzhong

    2010-06-01

    Onion-like functional microspheres with three alternate layers were obtained by aerosol-assisted self-assembly of a functional block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene-block-poly(2-vinylpyridine) (PTEPM-b-PS-b-P2VP). Through self-gelation reaction occurred in the PTEPM layers, organic/inorganic hybrid functional spheres with highly ordered concentric curved lamellar structure were prepared. Using these hybrid onion-like microspheres as templates, gold ions were entrapped into the P2VP layers and then gold nanoparticles located in each P2VP layers were formed by a reduction. By dispersing in acidic water, the onion-like polymeric spheres were broken and, as a result, sandwich-like nanoplates with curved morphology were obtained. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. In vitro Evaluation of Nateglinide-Loaded Microspheres Formulated ...

    African Journals Online (AJOL)

    Keywords: Nateglinide, Microspheres, Micromeritics, Drug release, Ionic ... Oral drug delivery systems (DDS) are commonly divided into immediate release and modified release systems. ..... Albumin Microspheres for Potential Intramuscular.

  11. Development of lovastatin-loaded poly(lactic acid microspheres for sustained oral delivery: in vitro and ex vivo evaluation

    Directory of Open Access Journals (Sweden)

    Guan QG

    2015-02-01

    Full Text Available Qigang Guan,1 Wei Chen,2 Xianming Hu2 1Department of Cardiology, The First Affiliated Hospital of China Medical University, Shenyang, People’s Republic of China; 2Department of Pharmaceutical, Shenyang Institute of Pharmaceutical Industry, Shenyang, People’s Republic of China Background: A novel lovastatin (LVT-loaded poly(lactic acid microsphere suitable for oral administration was developed in this study, and in vitro and in vivo characteristics were evaluated. Methods: The designed microspheres were obtained by an improved emulsion-solvent evaporation method. The morphological examination, particle size, encapsulation ratio, drug loading, and in vitro release were characterized. Pharmacokinetics studies were used to show that microspheres possess more advantages than the conventional formulations. Results: By using the emulsion-solvent evaporation method, it was simple to prepare microspheres and easy to scale up production. The morphology of formed microspheres showed a spherical shape with a smooth surface, without any particle aggregation. Mean size of the microspheres was 2.65±0.69 µm; the encapsulation efficiency was 92.5%±3.6%, and drug loading was 16.7%±2.1%. In vitro release indicated that the LVT microspheres had a well-sustained release efficacy, and ex vivo studies showed that after LVT was loaded to microspheres, the area under the plasma concentration-time curve from zero to the last measurable plasma concentration point and the extrapolation to time infinity increased significantly, which represented 2.63-fold and 2.49-fold increases, respectively, compared to suspensions. The rate of ex vivo clearance was significantly reduced. Conclusion: This research proved that poly(lactic acid microspheres can significantly prolong the drug circulation time in vivo and can also significantly increase the relative bioavailability of the drug. Keywords: lovastatin, microspheres, PLA, in vitro release, pharmacokinetics 

  12. Evaluation of radiolabelled microspheres as digesta markers

    International Nuclear Information System (INIS)

    Young, B.A.; Turner, B.V.; Dixon, A.E.; Exley, D.M.; Young, S.B.; Abidin, Z.

    1991-01-01

    The suitability of microspheres as markers for measuring digesta kinetics in sheep was examined. Microspheres offer advantages of uniformity of size and density, and stability during passage through the gastrointestinal tract. They are commercially available labelled with the choice of one of eleven different radionuclides and can be easily measured in digesta and faecal material. Tests comparing several types of digesta markers gave different measures of kinetic parameters when the measurements were made concurrently in the same sheep. However, concurrent measurements derived from use of microspheres were consistent. Microspheres offer a new alternative for digestive studies. (author). 19 refs, 4 tabs

  13. Immunocapture of CD133-positive cells from human cancer cell lines by using monodisperse magnetic poly(glycidyl methacrylate) microspheres containing amino groups

    Energy Technology Data Exchange (ETDEWEB)

    Kuan, Wei-Chih [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China); Horák, Daniel, E-mail: horak@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Plichta, Zdeněk [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Lee, Wen-Chien [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China)

    2014-01-01

    Magnetic poly(glycidyl methacrylate)-based macroporous microspheres with an average particle size of 4.2 μm were prepared using a modified multi-step swelling polymerization method and by introducing amino functionality on their surfaces. Antibody molecules were oxidized on their carbohydrate moieties and bound to the amino-containing magnetic microspheres via a site-directed procedure. CD133-positive cells could be effectively captured from human cancer cell lines (HepG2, HCT116, MCF7, and IMR-32) by using magnetic microspheres conjugated to an anti-human CD133 antibody. After further culture, the immunocaptured CD133-expressing cells from IMR-32 proliferated and gradually detached from the magnetic microspheres. Flow-cytometric analysis confirmed the enrichment of CD133-expressing cells by using the antibody-bound magnetic microspheres. Such microspheres suitable for immunocapture are very promising for cancer diagnosis because the CD133-expressing cells in cancer cell lines have been suggested to be cancer stem cells. - Highlights: • Multi-step swelling polymerization produced poly(glycidyl methacrylate) microspheres. • Anti-human CD133 antibodies were bound to the amino-containing magnetic microspheres. • CD133-positive cells were effectively captured from human cancer cell lines. • Immunocaptured CD133-expressing cells proliferated and were detached from microspheres. • Enrichment of CD133-expressing cells was confirmed by flow-cytometric analysis.

  14. Investigation of emulsified, acid and acid-alkali catalyzed mesoporous bioactive glass microspheres for bone regeneration and drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Guohou [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); Chen, Xiaofeng, E-mail: chenxf@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); Dong, Hua [National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); School of Biological Science and Engineering, South China University of Technology, Guangzhou 510006 (China); Fang, Liming; Mao, Cong; Li, Yuli; Li, Zhengmao; Hu, Qing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China)

    2013-10-15

    Acid-catalyzed mesoporous bioactive glass microspheres (MBGMs-A) and acid-alkali co-catalyzed mesoporous bioactive glass microspheres (MBGMs-B) were successfully synthesized via combination of sol-gel and water-in-oil (W/O) micro-emulsion methods. The structural, morphological and textural properties of mesoporous bioactive glass microspheres (MBGMs) were characterized by various techniques. Results show that both MBGMs-A and MBGMs-B exhibit regularly spherical shape but with different internal porous structures, i.e., a dense microstructure for MBGMs-A and internally porous structure for MBGMs-B. {sup 29}Si NMR data reveal that MGBMs have low polymerization degree of silica network. The in vitro bioactivity tests indicate that the apatite formation rate of MBGMs-B was faster than that of MBGMs-A after soaking in simulated body fluid (SBF) solution. Furthermore, the two kinds of MBGMs have similar storage capacity of alendronate (AL), and the release behaviors of AL could be controlled due to their unique porous structure. In conclusion, the microspheres are shown to be promising candidates as bone-related drug carriers and filling materials of composite scaffold for bone repair. - Graphical abstract: The morphologies and microstructures of acid-catalyzed mesoporous bioactive glass microspheres (MBGMs-A) and acid-alkali co-catalyzed mesoporous bioactive glass microspheres (MBGMs-B) were observed by scanning electron microscope and transmission electron microscope. MBGMs-A exhibits a dense structure and a porous can be observed in MBGMs-B. The microspheres have a quick inducing-apatite formation ability and show a sustained release of alendronate (AL). Highlights: • A rapid method was reported to prepare mesoporous bioactive glass microspheres. • The addition of ammonia significantly shortens the preparation time. • Acid and acid-alkali co-catalyzed microspheres were studied for the first time. • The materials exhibited excellent in vitro bioactivity and

  15. Synthesis of BSA/Fe{sub 3}O{sub 4} magnetic composite microspheres for adsorption of antibiotics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Baoliang; Zhang, Hepeng; Li, Xiangjie; Lei, Xingfeng; Li, Chunmei; Yin, Dezhong; Fan, Xinlong; Zhang, Qiuyu, E-mail: qyzhang@nwpu.edu.cn

    2013-10-01

    BSA/Fe{sub 3}O{sub 4} magnetic composite microspheres with high saturation magnetization and paramagnetic property were prepared via inverse emulsion technology at room temperature, bovine serum albumin (BSA, 60 KD), magnetic nanoparticles (Fe{sub 3}O{sub 4}) and glutaraldehyde as macromonomer, inorganic particles and cross-linking agent, respectively. Fourier transform infrared (FTIR), scanning electron microscope (SEM), metalloscope, and particle size analyzer were used to characterize morphology and structure of composite microspheres. Vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA) were used to test magnetic properties of the synthesized samples, adsorption capacity of microspheres was determined by ultraviolet spectrophotometer (UV). The results showed that BSA/Fe{sub 3}O{sub 4} microspheres were 43 μm with relatively narrow particle size distribution, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 11 emu/g, and high magnetic content with a value of 57.29%. The main factors influencing properties of microspheres including raw material ratio, the amount of emulsifier and cross-linking agent, agitation speed were investigated and optimized. Furthermore, these microspheres accompanying with high separable and reusable efficient may have great potential application in the field of separation, in particular, removal of antibiotics. Adsorption capacities of the microspheres of four different kinds of antibiotics (erythromycin, streptomycin, tetracycline and chloramphenicol) ranging from 69.35 mg/g to 147.83 mg/g were obtained, and Langmuir isotherm model coincided with equilibrium data than that of the Freundlich model. - Highlights: • BSA/Fe{sub 3}O{sub 4} microspheres with high saturation magnetization were prepared. • BSA/Fe{sub 3}O{sub 4} microspheres for the removal of antibiotics are proposed. • The obtained results have significant importance in environmental processes.

  16. Core/shell PLGA microspheres with controllable in vivo release profile via rational core phase design.

    Science.gov (United States)

    Yu, Meiling; Yao, Qing; Zhang, Yan; Chen, Huilin; He, Haibing; Zhang, Yu; Yin, Tian; Tang, Xing; Xu, Hui

    2018-02-27

    Highly soluble drugs tend to release from preparations at high speeds, which make them need to be taken at frequent intervals. Additionally, some drugs need to be controlled to release in vivo at certain periods, so as to achieve therapeutic effects. Thus, the objective of this study is to design injectable microparticulate systems with controllable in vivo release profile. Biodegradable PLGA was used as the matrix material to fabricate microspheres using the traditional double emulsification-solvent evaporation method as well as improved techniques, with gel (5% gelatine or 25% F127) or LP powders as the inner phases. Their physicochemical properties were systemically investigated. Microspheres prepared by modified methods had an increase in drug loading (15.50, 16.72, 15.66%, respectively) and encapsulation efficiencies (73.46, 79.42, 74.40%, respectively) when compared with traditional methods (12.01 and 57.06%). The morphology of the particles was characterized by optical microscope (OM) and scanning electron microscopy (SEM), and the amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. To evaluate their release behaviour, the in vitro degradation, in vitro release and in vivo pharmacodynamics were subsequently studied. Traditional microspheres prepared in this study with water as the inner phase had a relatively short release period within 16 d when compared with modified microspheres with 5% gelatine as the inner phase, which resulted in a smooth release profile and appropriate plasma LP concentrations over 21 d. Thus this type of modified microspheres can be better used in drugs requiring sustained release. The other two formulations containing 25% F127 and LP micropowders presented two-stage release profiles, resulting in fluctuant plasma LP concentrations which may be suitable for drugs requiring controlled release. All the results suggested that drug release rates from

  17. Magnetic restricted-access microspheres for extraction of adrenaline, dopamine and noradrenaline from biological samples

    International Nuclear Information System (INIS)

    Xiao, Deli; Liu, Shubo; Liang, Liyun; Bi, Yanping

    2016-01-01

    Epoxy propyl bonded magnetic microspheres were prepared by atomic layer deposition using Fe 3 O 4 -SiO 2 microspheres as a core support material. Then, a restricted-access magnetic sorbent was prepared that contains diol groups on the external surface and m-aminophenylboronic acid groups on the internal surface. This kind of microspheres achieved excellent specific adsorption of the ortho-dihydroxy compounds (dopamine, adrenaline and noradrenaline). Following desorption with sorbitol, the ortho-dihydroxy compounds were quantified by HPLC. The limits of detection for dopamine, adrenaline and noradrenaline were 0.074, 0.053 and 0.095 μg mL −1 , respectively. Recoveries from spiked mice serum samples range from 80.2 to 89.1 %. (author)

  18. Tungsten Oxide Nanofibers Self-assembled Mesoscopic Microspheres as High-performance Electrodes for Supercapacitor

    International Nuclear Information System (INIS)

    Xu, Juan; Ding, Taotao; Wang, Jin; Zhang, Jun; Wang, Shuai; Chen, Changqing; Fang, Yanyan; Wu, Zhihao; Huo, Kaifu; Dai, Jiangnan

    2015-01-01

    Highlights: • WO 3 mesoscopic microspheres self-assembled by nanofibers. • Inorganic solvent H 2 O 2 play an integral role in the process of self-assembly. • WO 3 mesoscopic microspheres exhibit specific capacitance value of 797.05 F g −1 at a constant density of 0.5 A g −1 in 2 M H 2 SO 4 aqueous solution. • The WO 3 //AC asymmetric supercapacitor displays a maximum energy density of 97.61 Wh kg −1 and power density of 28.01 kW kg −1 . - Abstract: Mesoscopic WO 3 microspheres composed of self-assembly nanofibers were prepared by hydrothermal reaction of tungsten acid potassium and H 2 O 2 . The mesoscopic WO 3 microspheres offer desired porous properties and large effective active areas provided by intertwining nanofibers, thereby resulting in excellent supercapacitive properties due to facile electrolyte flow and fast reaction kinetics. In three electrode configuration, mesoscopic WO 3 microspheres exhibit specific capacitance value of 797.05 F g −1 at the current density of 0.5 A g −1 and excellent cycling stability without decay after 2000 cycles in 2 M H 2 SO 4 aqueous solution. These values are superior to other reported WO 3 composites. An asymmetric supercapacitor is constructed using the as-prepared WO 3 mesoscopic microspheres as the positive electrode and the activated carbon as the negative electrode, which displays excellent electrochemical performance with a maximum energy density of 97.61 Wh kg −1 and power density of 28.01 kW kg −1 . These impressive performances suggest that the mesoscopic WO 3 microspheres are promising electrode materials for supercapacitor

  19. Bioactive apatite incorporated alginate microspheres with sustained drug-delivery for bone regeneration application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haibin; Jiang, Fei; Ye, Song; Wu, Yingying; Zhu, Kaiping; Wang, Deping, E-mail: wdpshk@tongji.edu.cn

    2016-05-01

    The strontium-substituted hydroxyapatite microspheres (SrHA) incorporated alginate composite microspheres (SrHA/Alginate) were prepared via adding SrHA/alginate suspension dropwise into calcium chloride solution, in which the gel beads were formed by means of crosslinking reaction. The structure, morphology and in vitro bioactivity of the composite microspheres were studied by using XRD, SEM and EDS methods. The biological behaviors were characterized and analyzed through inductively coupled plasma optical emission spectroscopy (ICP-OES), CCK-8, confocal laser microscope and ALP activity evaluations. The experimental results indicated that the synthetic SrHA/Alginate showed similar morphology to the well-known alginate microspheres (Alginate) and both of them possessed a great in vitro bioactivity. Compared with the control Alginate, the SrHA/Alginate enhanced MC3T3-E1 cell proliferation and ALP activity by releasing osteoinductive and osteogenic Sr ions. Furthermore, vancomycin was used as a model drug to investigate the drug release behaviors of the SrHA/Alginate, Alginate and SrHA. The results suggested that the SrHA/Alginate had a highest drug-loading efficiency and best controlled drug release properties. Additionally, the SrHA/Alginate was demonstrated to be pH-sensitive as well. The increase of the pH value in phosphate buffer solution (PBS) accelerated the vancomycin release. Accordingly, the multifunctional SrHA/Alginate can be applied in the field of bioactive drug carriers and bone filling materials. - Highlights: • The pH-sensitive composite alginate beads incorporating Sr-doped HA microspheres (SrHA) have been prepared. • The incorporation of the SrHA enhanced the drug loading and release properties of the alginate microspheres. • The composite microspheres showed excellent osteogenic effect by releasing osteogenic Sr ions.

  20. Synthesis, characterisation and biomedical applications of curcumin conjugated chitosan microspheres.

    Science.gov (United States)

    Saranya, T S; Rajan, V K; Biswas, Raja; Jayakumar, R; Sathianarayanan, S

    2018-04-15

    Curcumin is a diaryl heptanoid of curcuminoids class obtained from Curcuma longa. It possesses various biological activities like anti-inflammatory, hypoglycemic, antioxidant, wound-healing, and antimicrobial activities. Chitosan is a biocompatible, biodegradable and non-toxic natural polymer which enhances the adhesive property of the skin. Chemical conjugation will leads to sustained release action and to enhance the bioavailability. This study aims to synthesis and characterize biocompatible curcumin conjugated chitosan microspheres for bio-medical applications. The Schiff base reaction was carried out for the preparation of curcumin conjugated chitosan by microwave method and it was characterised using FTIR and NMR. Curcumin conjugated chitosan microspheres (CCCMs) were prepared by wet milling solvent evaporation method. SEM analysis showed these CCCMs were 2-5μm spherical particles. The antibacterial activities of the prepared CCCMs were studied against Staphylococcus aureus and Escherichia coli, the zone of inhibition was 28mm and 23mm respectively. Antioxidant activity of the prepared CCCMs was also studied by DPPH and H 2 O 2 method it showed IC 50 esteem value of 216μg/ml and 228μg/ml, and anti-inflammatory activity results showed that CCCMs having IC 50 value of 45μg/ml. The results conclude that the CCCMs having a good antibacterial, antioxidant and anti-inflammatory activities. This, the prepared CCCMs have potential application in preventing skin infections. Copyright © 2017. Published by Elsevier B.V.

  1. A sonochemical route for the encapsulation of drug in magnetic microspheres

    International Nuclear Information System (INIS)

    Wu Shixi; Jiang Wei; Zhang Xiaojuan; Sun Huan; Zhang Wenyao; Dai Junjun; Liu Li; Chen Xiaolong; Li Fengsheng

    2012-01-01

    This study focused on the preparation and characterization of magnetic targeted antibiotic microspheres (MTAMs). MTAMs were prepared by a sonochemical method in the presence of hydrophobic Fe 3 O 4 nanoparticles and tetracycline. The properties of MTAMs were characterized by transmission electron microscopy, Fourier-transform infrared spectrum, thermogravimetric analysis, vibration sample magnetometry, and bacteriostatic experiment. The results indicated that the superparamagnetic microspheres have ultrafine size (below 230 nm), high saturation magnetization (80.90 emu/g), high biocompatibility, biodegradability, controlled-release, and antibiotic effect. It has been proved that MTAMs can carry out the function of magnetic targeted drugs delivery system by putting together magnetic materials and antibiotics. The possible formation mechanism of MTAMs was also discussed. In summary, MTAMs had potential in medical imaging, drug targeting, and catalysis. - Highlights: → Microspheres carry out the function of magnetic targeted drugs delivery system. → Microspheres exhibit high saturation magnetization and antibiotic effect. → Microspheres have a potential application in the biomedical field. → The sonochemical method is well controlled for the synthesis.

  2. 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

  3. Hierarchical ZnO microspheres built by sheet-like network: Large-scale synthesis and structurally enhanced catalytic performances

    International Nuclear Information System (INIS)

    Zhu Guoxing; Liu Yuanjun; Ji Zhenyuan; Bai Song; Shen Xiaoping; Xu Zheng

    2012-01-01

    Highlights: ► Hierarchical ZnO microspheres were prepared through a facile precursor procedure in the absence of self-assembled templates, organic additives, or matrices. ► The building blocks of microspheres, sheet-like ZnO networks, are porous mesocrystal terminated with (0 1 −1 0) crystal planes. ► The hierarchical ZnO microsphere catalyst exhibits structure-induced enhancement of catalytic performance and a strong durability. - Abstract: Large-scale novel hierarchical ZnO microspheres were fabricated by a facile precursor procedure in the absence of self-assembled templates, organic additives, or matrices. A field emission scanning electron microscopy (FESEM) image reveals that the ZnO microspheres with diameter of 5–18 μm are built by sheet-like ZnO networks with average thickness of 40 nm and length of several microns. High resolution transmission electron microscopy (HRTEM) image indicates that the building blocks, sheet-like ZnO networks, are porous mesocrystal terminated with {0 1 −1 0} crystal planes. A potential application of the ZnO microspheres as a catalyst in the synthesis of 5-substituted 1H-tetrazoles was investigated. It was found that the hierarchical ZnO microsphere catalyst exhibits structure-induced enhancement of catalytic performance and a strong durability.

  4. Phenyltrichlorosilane-functionalized magnesium oxide microspheres: Preparation, characterization and application for the selective extraction of dioxin-like polycyclic aromatic hydrocarbons in soils with matrix solid-phase dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Dongqin [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Jin, Jing [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); Li, Fang [Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen 518055 (China); Sun, Xiaoli [Department of Chemistry, Lishui University, Lishui 32300 (China); Dhanjai; Ni, Yuwen [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); Chen, Jiping, E-mail: chenjp@dicp.ac.cn [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China)

    2017-03-01

    Magnesium oxide microspheres functionalized with phenyltrichlorosilane (PTS-MgO) were synthesized by surface modification through silanization reaction, which was confirmed by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetry analysis (TGA) and N{sub 2} adsorption-desorption. The result indicated that PTS-MgO not only possessed the ability of enhancing the retention with PAHs, but also weakening the interference from chlorinated compounds. As a sorbent for the matrix solid-phase dispersion (MSPD) extraction, PTS-MgO was used to selectively extract seven dioxin-like polycyclic aromatic hydrocarbons (DL-PAHs) from soil samples. Various parameters affecting the recoveries of seven DL-PAHs were investigated and optimized, such as sorbent/sample mass ratio, grinding time, rinsing and eluting conditions. Under the optimized conditions, the developed method combining MSPD with HPLC-FLD exhibited good sensitivity (0.02–0.12 ng g{sup −1} detection of limits) and linearity (linear correlation coefficient greater than 0.9997). Satisfactory recoveries with DL-PAHs spiked at two levels (10 and 80 ng g{sup −1}) were obtained in the range of 72.2–113.1% with RSD < 9.6%, indicating that PTS-MgO had a potential in MSPD extraction of DL-PAHs in soils. Additionally, the proposed MSPD-HPLC-FLD method was also verified by detecting seven DL-PAHs in the standard reference soil. Based on the developed method, DL-PAHs in soil samples were detected with the concentration ranging from 70.08 to 555.05 ng g{sup −1} dry weight (dw). The total toxic equivalency quotients (TEQ) of seven DL-PAHs varied from 9.93 to 143.94 ng TEQ/g dw. - Highlights: • Phenyltrichlorosilane modified magnesium oxide microsphere (PTS-MgO) was presented. • PTS-MgO was used for a new sorbent material in matrix solid-phase dispersion. • The sorbent showed high selectivity for DL-PAHs with satisfactory recoveries obtained. • The

  5. Microspherical polyaniline/graphene nanocomposites for high performance supercapacitors

    Science.gov (United States)

    Cao, Hailiang; Zhou, Xufeng; Zhang, Yiming; Chen, Liang; Liu, Zhaoping

    2013-12-01

    Polyaniline/graphene nanocomposites with microspherical morphology and porous structure are prepared as electrode materials for supercapacitors. Using few-layer graphene obtained by liquid phase exfoliation of graphite as the raw material, porous graphene microspheres are produced by spray drying, and are then employed as the substrates for the growth of polyaniline nanowire arrays by in situ polymerization. In the composite, interconnected graphene sheets with few structural defects constitute a high-efficient conductive network to improve the electrical conductivity of polyaniline. Furthermore, the microspherical architecture prevents restacking of polyaniline/graphene composite nanosheets, thus facilitates fast diffusion of electrolytes. Consequently, the nanocomposite exhibits excellent electrochemical performance. A specific capacitance of 338 F g-1 is reached in 1 M H2SO4 at a scan rate of 20 mV s-1, and a high capacity retention rate of 87.4% after 10,000 cycles at a current density of 3 A g-1 can be achieved, which suggests that the polyaniline/graphene composite with such kind of 3D architecture is a promising electrode material for high-performance supercapacitors.

  6. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  7. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    , cured PDMS microspheres are coated with poly(methyl methacrylate) using a chemical process (solvent evaporation technique). Three solvents are used in three different experiments: dichloromethane, tetrahydrofuran, and acetone. The composition and morphology of the cured PDMS microspheres and PMMA coated...

  8. 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

  9. Resin 90Y microsphere activity measurements for liver brachytherapy

    International Nuclear Information System (INIS)

    Dezarn, William A.; Kennedy, Andrew S.

    2007-01-01

    The measurement of the radioactivity administered to the patient is one of the major components of 90 Y microsphere liver brachytherapy. The activity of 90 Y microspheres in a glass delivery vial was measured in a dose calibrator. The calibration value to use for 90 Y in the dose calibrator was verified using an activity calibration standard provided by the microsphere manufacturer. This method allowed for the determination of a consistent, reproducible local activity standard. Additional measurements were made to determine some of the factors that could affect activity measurement. The axial response of the dose calibrator was determined by the ratio of activity measurements at the bottom and center of the dose calibrator. The axial response was 0.964 for a glass shipping vial, 1.001 for a glass V-vial, and 0.988 for a polycarbonate V-vial. Comparisons between activity measurements in the dose calibrator and those using a radiation survey meter were found to agree within 10%. It was determined that the dose calibrator method was superior to the survey meter method because the former allowed better defined measurement geometry and traceability of the activity standard back to the manufacturer. Part of the preparation of resin 90 Y microspheres for patient delivery is to draw out a predetermined activity from a shipping vial and place it into a V-vial for delivery to the patient. If the drawn activity was placed in a glass V-vial, the activity measured in the dose calibrator with a glass V-vial was 4% higher than the drawn activity from the shipping vial standard. If the drawn activity was placed in a polycarbonate V-vial, the activity measured in the dose calibrator with a polycarbonate V-vial activity was 20% higher than the drawn activity from the shipping vial standard. Careful characterization of the local activity measurement standard is recommended instead of simply accepting the calibration value of the dose calibrator manufacturer

  10. U3O8 microspheres sintering kinetics

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1986-01-01

    U 3 O 8 microspheres sintering kinetics was determined using a hot-stage optical microscopy apparatus, able to reach temperature up to 1350 0 C in controlled atmospheres. The sintered material had its microstructure analysed by optical and electron microscopy. The microspheres were characterized initialy utilizing X-ray diffractometry and thermogravimetry. The equation which describes the microspheres shrinkage in function of the time was obtained using finite difference analysis X-ray diffractometry indicated hexagonal structure for the microspheres main starting material, ammonium diuranate thermogravimetric analysis showed reduction of this material to U 3 O 8 at 600 0 C. Ceramography results showed 5 hours sintered microspheres grain sizes G vary with the temperature. Sintered U 3 O 8 micrographs compared with published results for UO 2 , indicate similar homogeneity microstructural characteristics and suggest the processed micorspheres to be potentially useful as nuclear fuels. (Author) [pt

  11. Magnetic susceptibility characterisation of superparamagnetic microspheres

    Science.gov (United States)

    Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

    2018-04-01

    The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

  12. Ibuprofen-loaded microspheres based on a co-polymer of Eudragit ...

    African Journals Online (AJOL)

    The objective of this study was to encapsulate ibuprofen in microspheres based on a co-polymer of Eudragit® RS100 and RL100 with a view to achieving a controlled release of the incorporated drug. The microparticles were prepared by an o/o emulsion-solvent evaporation method using varying polymer ratios and ...

  13. Formulation and in vitro Evaluation of Eudragit® Microspheres of ...

    African Journals Online (AJOL)

    The prepared microspheres were characterized for their micromeritic properties and drug loading, as well by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, x-ray powder diffractometry and scanning electron microscopy. The in vitro release studies were performed in pH 6.8, phosphate buffer ...

  14. Effect of microwell chip structure on cell microsphere production of various animal cells.

    Science.gov (United States)

    Sakai, Yusuke; Yoshida, Shirou; Yoshiura, Yukiko; Mori, Rhuhei; Tamura, Tomoko; Yahiro, Kanji; Mori, Hideki; Kanemura, Yonehiro; Yamasaki, Mami; Nakazawa, Kohji

    2010-08-01

    The formation of three-dimensional cell microspheres such as spheroids, embryoid bodies, and neurospheres has attracted attention as a useful culture technique. In this study, we investigated a technique for effective cell microsphere production by using specially prepared microchip. The basic chip design was a multimicrowell structure in triangular arrangement within a 100-mm(2) region in the center of a polymethylmethacrylate (PMMA) plate (24x24 mm(2)), the surface of which was modified with polyethylene glycol (PEG) to render it nonadhesive to cells. We also designed six similar chips with microwell diameters of 200, 300, 400, 600, 800, and 1000 microm to investigate the effect of the microwell diameter on the cell microsphere diameter. Rat hepatocytes, HepG2 cells, mouse embryonic stem (ES) cells, and mouse neural progenitor/stem (NPS) cells formed hepatocyte spheroids, HepG2 spheroids, embryoid bodies, and neurospheres, respectively, in the microwells within 5 days of culture. For all the cells, a single microsphere was formed in each microwell under all the chip conditions, and such microsphere configurations remained throughout the culture period. Furthermore, the microsphere diameters of each type of cell were strongly positively correlated with the microwell diameters of the chips, suggesting that microsphere diameter can be factitiously controlled by using different chip conditions. Thus, this chip technique is a promising cellular platform for tissue engineering or regenerative medicine research, pharmacological and toxicological studies, and fundamental studies in cell biology. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. In vitro evaluation and intra-articular administration of biodegradable microspheres containing naproxen sodium.

    Science.gov (United States)

    Bozdağ, S; Caliş, S; Kaş, H S; Ercan, M T; Peksoy, I; Hincal, A A

    2001-01-01

    The dispersion of non-steroidal antiinflammatory drugs (NSAIDs) into biodegradable polymeric matrices have been accepted as a good approach for obtaining a therapeutic effect in a predetermined period of time meanwhile minimizing the side effects of NSAIDs. In the present study, it was aimed to prepare Naproxen Sodium (NS), (a NSAID) loaded microsphere formulation using natural Bovine Serum Albumin (BSA) and synthetic biodegradable polymers such as poly(lactide-co-glycolic acid) (PLGA) (50:50 MW 34,000 and 88,000 Da) for intra-articular administration, and to study the retention of the drug at the site of injection in the knee joint. NS incorporated microspheres were evaluated in vitro for particle size (the mean particle size; for BSA microspheres, 10.0 +/- 0.3 microm, for PLGA microspheres, 9.0 +/- 0.2 and 5.0 +/- 0.1 microm for MW 34,000 and 88,000 Da, respectively), yield value, drug loading, surface morphology and drug release. For in vivo studies, monoarticular arthritis was induced in the left knee joints of rabbits by using ovalbumin and Freund's Complete Adjuvant as antigen and adjuvant. A certain time (4 days) is allowed for the formation of arthritis in the knee joints, then the NS loaded microspheres were injected directly into the articular cavity. At specific time points, gamma scintigrams were obtained to determine the residence time of the microspheres in knee joints, in order to determine the most suitable formulation. This study indicated that PLGA, a synthetic polymer, is more promising than the natural type BSA microspheres for an effective cure of mono-articular arthritis in rabbits.

  16. Biocompatibility Research of a Novel pH Sensitive Ion Exchange Resin Microsphere.

    Science.gov (United States)

    Liu, Hongfei; Shi, Shuangshuang; Pan, Weisan; Sun, Changshan; Zou, Xiaomian; Fu, Min; Feng, Yingshu; Ding, Hui

    2014-01-01

    The main objective of this study was to investigate biocompatibility and provide in-vivo pharmacological and toxicological evidence for further investigation of the possibility of pH sensitive ion exchange resin microsphere for clinical utilizations. Acute toxicity study and general pharmacological studies were conducted on the pH sensitive ion exchange resin microsphere we prepared. The general pharmacological studies consist of the effects of the pH sensitive ion exchange resin microsphere on the nervous system of mice, the functional coordination of mice, the hypnosis of mice treated with nembutal at subliminal dose, the autonomic activities of tested mice, and the heart rate, blood pressure, ECG and breathing of the anesthetic cats. The LD50 of pH sensitive ion exchange resin microsphere after oral administration was more than 18.84 g·Kg(-1). Mice were orally administered with 16 mg·Kg(-1), 32 mg·Kg(-1) and 64 mg·Kg(-1) of pH sensitive ion exchange resin microsphere and there was no significant influence on mice nervous system, general behavior, function coordination, hypnotic effect treated with nembutal at subliminal dose and frequency of autonomic activities. Within the 90 min after 5 mg·Kg(-1), 10 mg·Kg(-1), 20 mg·Kg(-1) pH sensitive ion exchange resin microsphere was injected to cat duodenum, the heart rate, blood pressure, breathing and ECG of the cats didn't make significant changes in each experimental group compared with the control group. The desirable pharmacological and toxicological behaviors of the pH sensitive ion exchange resin microsphere exhibited that it has safe biocompatibility and is possible for clinical use.

  17. Yttrium-86-labelled human serum albumin microspheres: relation of surface structure with in vivo stability

    International Nuclear Information System (INIS)

    Schiller, Eik; Bergmann, Ralf; Pietzsch, Jens; Noll, Bernhard; Sterger, Antje; Johannsen, Bernd; Wunderlich, Gerd; Pietzsch, Hans-Juergen

    2008-01-01

    Introduction: Radiolabelled particles are an attractive tool in the therapy of malignancies of the liver. We consider particles manufactured from denatured human serum albumin (HSA) as useful carriers of therapeutic radionuclides. Covalent attachment of suitable chelators onto the surface of the spheres promises an easy access to radiolabelled HSA microspheres. Methods: We synthesized 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) bearing smooth, medium-rough and rough surfaced HSA microspheres (mean diameter: 25 μm). In vitro stability of 86 Y-labelled particles was determined after incubation in human plasma and in a DTPA challenge experiment. In vivo stability of 86 Y DOTA-HSA microspheres was determined after single intravenous application in rats. Subsequently, the particles were completely trapped in the lung microvasculature. Thus, the lung serves in our experiments as target organ. Results: DOTA-HSA microspheres were 86 Y labelled in reproducible high yields (>95%). No differences between smooth and rough surfaced spheres were found for both DOTA coupling and 86 Y labelling. Labelled microspheres showed high in vitro stability in human plasma and in DTPA solution with only 8±1% and 2±0% loss of radioactivity from the surface, respectively, 48 h postinjection (pi). The three batches (smooth, medium-rough and rough surfaced microspheres) differed considerably in their radioactivity recovery in the lungs of rats 48 h pi. Smooth particles showed the highest in vivo stability of the radiolabel on the surface of the spheres, presumably because of slower proteolytic degradation. Conclusion: We found that for the preparation of HSA-derived microspheres for radiotherapeutic application, smooth surfaced spheres are superior to rough spheres due to their higher in vivo stability of the radionuclide fixation

  18. Influence of Sodium Alginate on Hypoglycemic Activity of Metformin Hydrochloride in the Microspheres Obtained by the Spray Drying

    Directory of Open Access Journals (Sweden)

    Marta Szekalska

    2016-01-01

    Full Text Available Alginate microspheres with metformin hydrochloride were prepared by the spray drying method in order to improve residence time of drug in the stomach. Nine formulations (F1–F9 with various drug : polymer ratio (1 : 2, 1 : 1, and 2 : 1 and different sodium alginate concentration (1%, 2%, and 3% were evaluated for size, morphology, drug loading, Zeta potential, and swelling degree. In vitro drug release, mathematical release profile, and physical state of microspheres were also evaluated. Optimal formulation characterized by the highest drug loading was formulation F6 (drug : polymer ratio 2 : 1 and 2% alginate solution. Based on glucose uptake in Saccharomyces cerevisiae cells and α-amylase inhibition tests, it could be concluded that alginate microspheres enhance hypoglycemic activity of metformin hydrochloride evaluated in vitro. Designed microspheres are promising as alternative, multicompartment dosage form for metformin hydrochloride delivery.

  19. Hydroxyapatite-armored poly(ε-caprolactone) microspheres and hydroxyapatite microcapsules fabricated via a Pickering emulsion route.

    Science.gov (United States)

    Fujii, Syuji; Okada, Masahiro; Nishimura, Taiki; Maeda, Hayata; Sugimoto, Tatsuya; Hamasaki, Hiroyuki; Furuzono, Tsutomu; Nakamura, Yoshinobu

    2012-05-15

    Hydroxyapatite (HAp) nanoparticle-armored poly(ε-caprolactone) (PCL) microspheres were fabricated via a "Pickering-type" emulsion solvent evaporation method in the absence of any molecular surfactants. It was clarified that the interaction between carbonyl/carboxylic acid groups of PCL and the HAp nanoparticles at an oil-water interface played a crucial role in the preparation of the stable Pickering-type emulsions and the HAp nanoparticle-armored microspheres. The HAp nanoparticle-armored PCL microspheres were characterized in terms of size, size distribution, morphology, and chemical compositions using scanning electron microscopy, laser diffraction, energy dispersive X-ray microanalysis, and thermogravimetric analysis. The presence of HAp nanoparticles at the surface of the microspheres was confirmed by scanning electron microscopy and energy dispersive X-ray microanalysis. Pyrolysis of the PCL cores led to the formation of the corresponding HAp hollow microcapsules. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. One-pot solvothermal route to self-assembly of cauliflower-shaped CdS microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Ge Ming [Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071 (China); Cui Yao [Institute of New Energy Material Chemistry, and Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071 (China); Liu Lu, E-mail: liul@nankai.edu.cn [Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071 (China); Zhou Zhen, E-mail: zhouzhen@nankai.edu.cn [Institute of New Energy Material Chemistry, and Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071 (China)

    2011-05-15

    Nearly monodispersed cauliflower-shaped CdS microspheres were prepared through a simple one-step solvothermal route on a large scale by employing sodium dodecyl sulfate (SDS) as the surfactant. Images by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) indicate that cauliflower-shaped CdS microspheres with diameters in the range from 1.3 to 4.5 {mu}m are assembled by nanoparticles with an average diameter of approximately 30 nm. The possible formation mechanism of the cauliflower-shaped CdS microspheres was also proposed. The photovoltaic activity of cauliflower-shaped CdS architectures has been investigated, indicating that the as-obtained CdS microspheres exhibited higher photovoltaic performance in comparison with CdS nanoparticles.

  1. One pot synthesis of Ag nanoparticle modified ZnO microspheres in ethylene glycol medium and their enhanced photocatalytic performance

    International Nuclear Information System (INIS)

    Tian Chungui; Li Wei; Pan Kai; Zhang Qi; Tian Guohui; Zhou Wei; Fu Honggang

    2010-01-01

    Ag nanoparticles (NPs) modified ZnO microspheres (Ag/ZnO microspheres) were prepared by a facile one pot strategy in ethylene glycol (EG) medium. The EG played two important roles in the synthesis: it could act as a reaction media for the formation of ZnO and reduce Ag + to Ag 0 . A series of the characterizations indicated the successful combination of Ag NPs with ZnO microspheres. It was shown that Ag modification could greatly enhance the photocatalytic efficiency of ZnO microspheres by taking the photodegradation of Rhodamine B as a model reaction. With appropriate ratio of Ag and ZnO, Ag/ZnO microspheres showed the better photocatalytic performance than commercial Degussa P-25 TiO 2 . Photoluminescence and surface photovoltage spectra demonstrated that Ag modification could effectively inhibit the recombination of the photoinduced electron and holes of ZnO. This is responsible for the higher photocatalytic activity of Ag/ZnO composites. -- Graphical abstract: A 'one-pot' strategy was developed for preparing the Ag/ZnO microspheres in ethylene glycol. The composites exhibited superior photocatalytic performance for photodegradation of Rhodamine B dye in water. Display Omitted

  2. A facile approach to fabricate Au nanoparticles loaded SiO{sub 2} microspheres for catalytic reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Mingyi, E-mail: mingyitjucu@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Huang, Guanbo, E-mail: gbhuang2007@hotmail.com [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Li, Xianxian; Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

    2015-07-15

    Hydrophilic and biocompatible macromolecules were used to improve and simplify the process for the fabrication of core/shell SiO{sub 2}@Au composite particles. The influence of polymers on the morphology of SiO{sub 2}@Au particles with different size of SiO{sub 2} cores was analyzed by transmission electron microscopy and scanning electron microscopy. The optical property of the SiO{sub 2}@Au particles was studied with UV–Vis spectroscopy. The results indicate that the structure and composition of macromolecules affect the morphology of Au layers on SiO{sub 2} microspheres. The SiO{sub 2}@Au particles prepared in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) have thin and complete Au nanoshells owing to their inducing act in preferential growth of Au nanoparticles along the surface of SiO{sub 2} microspheres. SiO{sub 2}@Au particles can be also prepared from SiO{sub 2} microspheres modified with 3-aminopropyltrimethoxysilane in the presence of PVA or PVP. This offers a simple way to fabricate a Au layer on SiO{sub 2} or other microspheres. The SiO{sub 2}@Au particles demonstrated high catalytic activity in the reduction of 4-nitrophenol. - Highlights: • Facile direct deposition method for Au nanoparticles on silica microspheres. • Influence of different types of macromolecule on the formation of Au shell. • High catalytic performance of Au nanoparticles on silica microspheres.

  3. A facile approach to fabricate Au nanoparticles loaded SiO2 microspheres for catalytic reduction of 4-nitrophenol

    International Nuclear Information System (INIS)

    Tang, Mingyi; Huang, Guanbo; Li, Xianxian; Pang, Xiaobo; Qiu, Haixia

    2015-01-01

    Hydrophilic and biocompatible macromolecules were used to improve and simplify the process for the fabrication of core/shell SiO 2 @Au composite particles. The influence of polymers on the morphology of SiO 2 @Au particles with different size of SiO 2 cores was analyzed by transmission electron microscopy and scanning electron microscopy. The optical property of the SiO 2 @Au particles was studied with UV–Vis spectroscopy. The results indicate that the structure and composition of macromolecules affect the morphology of Au layers on SiO 2 microspheres. The SiO 2 @Au particles prepared in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) have thin and complete Au nanoshells owing to their inducing act in preferential growth of Au nanoparticles along the surface of SiO 2 microspheres. SiO 2 @Au particles can be also prepared from SiO 2 microspheres modified with 3-aminopropyltrimethoxysilane in the presence of PVA or PVP. This offers a simple way to fabricate a Au layer on SiO 2 or other microspheres. The SiO 2 @Au particles demonstrated high catalytic activity in the reduction of 4-nitrophenol. - Highlights: • Facile direct deposition method for Au nanoparticles on silica microspheres. • Influence of different types of macromolecule on the formation of Au shell. • High catalytic performance of Au nanoparticles on silica microspheres

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

    International Nuclear Information System (INIS)

    Song, Kedong; Liu, Yingchao; Macedo, Hugo M.; Jiang, Lili; Li, Chao; Mei, Guanyu; Liu, Tianqing

    2013-01-01

    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 −2 mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a

  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. 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

  7. [Measurement of the blood flow in various areas of the rat brain by means of microspheres].

    Science.gov (United States)

    Deroo, J; Gerber, G B

    1976-01-01

    A method is described to measure regional blood flow in different structures of the rat brain. Microspheres (15 micron) are injected, the brain is sectioned, stained for myeline, radioautographs are prepared and the microspheres in the different structures are counted. The values obtained for different brain structures are counted. The values obtained for different brain regions (cortex, corpus callosum, thalamus hipocampus, hypothalamic region, colliculi, cerebellum, pons, medulla) compare well with those published by others on larger animals. In rats fed 1% of lead from birth, higher blood flow is found in the cortex and a lower one in the interior part of the brain compared to controls.

  8. Facile Synthesis of Magnetic Mesoporous Hollow Carbon Microspheres for Rapid Capture of Low-Concentration Peptides

    OpenAIRE

    Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2014-01-01

    Mesoporous and hollow carbon microspheres embedded with magnetic nanoparticles (denoted as MHM) were prepared via a facile self-sacrificial method for rapid capture of low-abundant peptides from complex biological samples. The morphology, structure, surface property, and magnetism were well-characterized. The hollow magnetic carbon microspheres have a saturation magnetization value of 130.2 emu g?1 at room temperature and a Brunauer?Emmett?Teller specific surface area of 48.8 m2 g?1 with an a...

  9. Hierarchical Mn₂O₃ Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances.

    Science.gov (United States)

    Gong, Feilong; Lu, Shuang; Peng, Lifang; Zhou, Jing; Kong, Jinming; Jia, Dianzeng; Li, Feng

    2017-11-23

    Porous Mn₂O₃ microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn₂O₃ microspheres by first producing MnCO₃ microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO₃ microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn₂O₃ nanorods consisting of microspheres. The C@Mn₂O₃ microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn₂O₃ microspheres prepared at 500 °C show high specific capacitances of 383.87 F g -1 at current density of 0.5 A g -1 , and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn₂O₃ microspheres after annealed at 500 °C and activated carbon (AC) show an energy density of up to 77.8 Wh kg -1 at power density of 500.00 W kg -1 , and a maximum power density of 20.14 kW kg -1 at energy density of 46.8 Wh kg -1 . We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D) hierarchical structure in-situ coated with carbon.

  10. Hierarchical Mn2O3 Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

    Science.gov (United States)

    Gong, Feilong; Lu, Shuang; Peng, Lifang; Zhou, Jing; Kong, Jinming; Jia, Dianzeng; Li, Feng

    2017-01-01

    Porous Mn2O3 microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn2O3 microspheres by first producing MnCO3 microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO3 microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn2O3 nanorods consisting of microspheres. The C@Mn2O3 microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn2O3 microspheres prepared at 500 °C show high specific capacitances of 383.87 F g−1 at current density of 0.5 A g−1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn2O3 microspheres after annealed at 500 °C and activated carbon (AC) show an energy density of up to 77.8 Wh kg−1 at power density of 500.00 W kg−1, and a maximum power density of 20.14 kW kg−1 at energy density of 46.8 Wh kg−1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D) hierarchical structure in-situ coated with carbon. PMID:29168756

  11. Hierarchical Mn2O3 Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

    Directory of Open Access Journals (Sweden)

    Feilong Gong

    2017-11-01

    Full Text Available Porous Mn2O3 microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn2O3 microspheres by first producing MnCO3 microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO3 microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn2O3 nanorods consisting of microspheres. The C@Mn2O3 microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn2O3 microspheres prepared at 500 °C show high specific capacitances of 383.87 F g−1 at current density of 0.5 A g−1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn2O3 microspheres after annealed at 500 °C and activated carbon (AC show an energy density of up to 77.8 Wh kg−1 at power density of 500.00 W kg−1, and a maximum power density of 20.14 kW kg−1 at energy density of 46.8 Wh kg−1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D hierarchical structure in-situ coated with carbon.

  12. Uniform Cu2Cl(OH)3 hierarchical microspheres: A novel adsorbent for methylene blue adsorptive removal from aqueous solution

    International Nuclear Information System (INIS)

    Wei, Wei; Gao, Pin; Xie, Jimin; Zong, Sekai; Cui, Henglv; Yue, Xuejie

    2013-01-01

    Using the solution phase method without any surfactants or templates, the hierarchical of Cu 2 Cl(OH) 3 microspheres were synthesized by freeze drying. The size and surface area of the microspheres are ca. 1–2 µm and 76.61 m 2 g −1 , respectively. A possible formation mechanism is presented based on the experimental results. Methylene blue was chosen to investigate the adsorption capacity of the as-prepared adsorbent. The effects of various experimental parameters, such as pH, initial dye concentration, and contact time were investigated. The results showed that the dye removal increased with the increasing in the initial concentration of the dye and also increased in the amount of microspheres used and initial pH. Adsorption data fitted well with the Freundlich adsorption isotherm. The thermodynamic analysis presented the exothermic, spontaneous and more ordered arrangement process. The microspheres could be employed effective for removal of dyes from aqueous solution. - Graphical abstract: The single-crystalline hierarchical Cu 2 Cl(OH) 3 spheres can be prepared for the first time by using a template-free process through freeze-drying. Meanwhile, the hierarchical spheres exhibited high adsorption capacity to methylene blue. Display Omitted - Highlights: • Cu 2 Cl(OH) 3 microspheres were successfully synthesized through a freeze drying process. • A possible formation mechanism of hierarchical microspheres was presented. • The Cu 2 Cl(OH) 3 microspheres have high methylene blue adsorption capacity. • Methylene blue adsorption is a spontaneous and exothermic process. • The adsorption mechanism of microspheres onto dye was proposed in detail

  13. PEGylation controls attachment and engulfment of monodisperse magnetic poly(2-hydroxyethyl methacrylate) microspheres by murine J774.2 macrophages

    Science.gov (United States)

    Horák, Daniel; Hlidková, Helena; Klyuchivska, Olga; Grytsyna, Iryna; Stoika, Rostyslav

    2017-12-01

    The first objective of this work was to prepare biocompatible magnetic polymer microspheres with reactive functional groups that could withstand nonspecific protein adsorption from biological media. Carboxyl group-containing magnetic poly(2-hydroxyethyl methacrylate) (mgt.PHEMA) microspheres ∼4 μm in size were prepared by multistage swelling polymerization, precipitation of iron oxide inside their pores, and coating with an α-methoxy-ω-amino poly(ethylene glycol) (CH3O-PEG750-NH2 or CH3O-PEG5,000-NH2)/α-amino-ω-t-Boc-amino poly(ethylene glycol) (H2N-PEG5,000-NH-t-Boc) mixture. The mgt.PHEMA@PEG microspheres contained ∼10 μmol COOH per g. Biocompatibility of the particles was evaluated by their treatment with human embryonic kidney cells of the HEK293 line. The microspheres did not interfere with the growth of these cells, suggesting that the particles can be considered non-toxic. A second goal of this study was to address on the interaction of the developed microspheres with macrophages that commonly eliminate foreign microbodies appearing in organisms. Murine J774.2 macrophages (J774.2) were cultured in the presence of the neat and PEGylated microspheres for 2 h. Mgt.PHEMA@PEG5,000 microspheres significantly adhered to the surface of J774.2 macrophages but were minimally engulfed. Due to these properties, the mgt.PHEMA@PEG microspheres might be useful for application in drug delivery systems and monitoring of the efficiency of phagocytosis.

  14. Template-directed synthesis of MS (M=Cd, Zn) hollow microsphere via hydrothermal method

    Science.gov (United States)

    Wang, Shi-Ming; Wang, Qiong-Sheng; Wan, Qing-Li

    2008-05-01

    CdS, ZnS hollow microspheres were prepared with chitosan as the synthesis template at 140 and 150 °C, respectively, by hydrothermal method. The resultant products were characterized by X-ray diffraction (XRD) measurements in order to determine the crystalline phase of the products. The structural and morphological features of the nanoparticles were investigated by transmission electron microscopy (TEM) and ultraviolet-visible diffuse reflection spectroscopy (DRS). The experimental results indicated that all the nanoparticles aggregated into hollow microspheres and chitosan as a template played an important role in the formation of hollow microspheres. In addition, an intermediate complex structure-controlling possible reaction mechanism was proposed in this paper.

  15. Interaction between dimethyldioctadecylammonium bromide-modified PLGA microspheres and hyaluronic acid

    Science.gov (United States)

    Mulia, Kamarza; Devi, Krisanti, Elsa

    2017-02-01

    In application of intravitreal injection, an extended drug delivery system is desired so that the frequency of injection to treat diabetic retinopathy may be reduced. Poly(lactic-co-glycolic acid) polymer (PLGA) was used to encapsulate a model drug in the form of microspheres. The zeta potential of dimethyldioctadecylammonium bromide (DDAB)-modified PLGA microspheres in water was proportional to the DDAB concentration used in the preparation step, up to +57.8 mV. The scanning electron microscope pictures and the zeta potential data (SEM) confirmed that the surface of the PLGA has been modified by the cationic surfactant and that electrostatic interaction between the positively charged microspheres and the negatively charged vitreous were present.

  16. Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

    International Nuclear Information System (INIS)

    Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao Alberto

    2011-01-01

    Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

  17. Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de, E-mail: douglas.miyamoto@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia

    2011-07-01

    Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

  18. Development of andrographolide loaded PLGA microspheres: optimization, characterization and in vitro-in vivo correlation.

    Science.gov (United States)

    Jiang, Yunxia; Wang, Fang; Xu, Hui; Liu, Hui; Meng, Qingguo; Liu, Wanhui

    2014-11-20

    The purpose of this study was to develop a sustained-release drug delivery system based on the injectable PLGA microspheres loaded with andrographolide. The andrographolide loaded PLGA microspheres were prepared by emulsion solvent evaporation method with optimization of formulation using response surface methodology (RSM). Physicochemical characterization, in vitro release behavior and in vivo pharmacokinetics of the optimized formulation were then evaluated. The percent absorbed in vivo was determined by deconvolution using the Loo-Riegelman method, and then the in vitro-in vivo correlation (IVIVC) was established. Results showed that the microspheres were spherical with a smooth surface. Average particle size, entrapment efficiency and drug loading were found to be 53.18±2.11 μm, 75.79±3.02% and 47.06±2.18%, respectively. In vitro release study showed a low initial burst release followed by a prolonged release up to 9 days and the release kinetics followed the Korsmeyer-Peppas model. After a single intramuscular injection, the microspheres maintained relatively high plasma concentration of andrographolide over one week. A good linear relationship was observed between the in vitro and in vivo release behavior (R(2)=0.9951). These results suggest the PLGA microspheres could be developed as a potential delivery system for andrographolide with high drug loading capacity and sustained drug release. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Novel Bi/BiOBr/AgBr composite microspheres: Ion exchange synthesis and photocatalytic performance

    Science.gov (United States)

    Lyu, Jianchang; Li, Zhenlu; Ge, Ming

    2018-06-01

    Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO3. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O2•-) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension.

  20. Fluorescent probe encapsulated hydrogel microsphere for selective and reversible detection of Hg{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhenhu; Wang, Fang; Qiang, Jian; Zhang, Zhijie; Chen, Yahui; Wang, Yong; Zhang, Wei; Chen, Xiaoqiang

    2017-03-15

    We developed a simple and sensitive hydrogel sensor in the form of microspheres by using fluorescence probe encapsulated within a hydrogel matrix for the detection of Hg{sup 2+}. The traditional fluorescence probes suspended in solution are not transportable and recoverable. To overcome these disadvantages, we devised poly(ethylene glycol) diacrylate-based hydrogel microspheres in which fluorescence probe (R19S) was embedded at high density. The functionalized hydrogel microspheres were prepared by combining a microfluidic device with UV light. The hydrogel microspheres-based sensor exhibited good selectivity to Hg{sup 2+} among various metal ions and high sensitivity with a detection limit of 90 nM. Furthermore, after binding with Hg{sup 2+}, the R19S encapsulated hydrogel microspheres can be separated from testing samples easily and treated with the solution containing KI to remove Hg{sup 2+} and realize reusable detection. The current work may offer a new method for Hg{sup 2+} recognition with a more efficient manner.

  1. Enhanced pervaporative desulfurization by polydimethylsiloxane membranes embedded with silver/silica core-shell microspheres

    International Nuclear Information System (INIS)

    Cao Ruijian; Zhang Xiongfei; Wu Hong; Wang Jingtao; Liu Xiaofei; Jiang Zhongyi

    2011-01-01

    Pervaporative desulfurization based on membrane technology provides a promising alternative for removal of sulfur substances (as represented by thiophene) in fluid catalytic cracking (FCC) gasoline. The present study focused on the performance enhancement of polydimethylsiloxane (PDMS) membrane by incorporation of core-shell structured silver/silica microspheres. A silane coupling agent, N-[3-(trimethoxysily)propyl]-ethylenediamine (TSD), was used to chelate the Ag + via its amino groups and attach the silver seeds onto the silica surface via condensation of its methoxyl groups. The resultant microspheres were characterized by Zeta-positron annihilation lifetime spectroscopy (ZetaPALS), inductively coupled plasmaoptical emission spectrophotometer (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Ag + /SiO 2 -PDMS composite membranes were prepared by blending PDMS with the as-synthesized silver/silica microspheres. PALS analysis was used to correlate the apparent fractional free volume with permeation flux. The sorption selectivity towards thiophene was enhanced after incorporation of silver/silica microspheres due to the π-complexation between the silver on the microsphere surface and the thiophene molecules. The pervaporative desulfurization performance of the composite membrane was investigated using thiophene/n-octane mixture as a model gasoline. The composite membrane exhibited an optimum desulfurization performance with a permeation flux of 7.76 kg/(m 2 h) and an enrichment factor of 4.3 at the doping content of 5%.

  2. Failure mode and effects analysis in a dual-product microsphere brachytherapy environment.

    Science.gov (United States)

    Younge, Kelly Cooper; Lee, Choonik; Moran, Jean M; Feng, Mary; Novelli, Paula; Prisciandaro, Joann I

    We performed a failure mode and effects analysis (FMEA) during the addition of a new microspheres product into our existing microsphere brachytherapy program to identify areas for safety improvements. A diverse group of team members from the microsphere program participated in the project to create a process map, identify and score failure modes, and discuss programmatic changes to address the highest ranking items. We developed custom severity ranking scales for staff- and institution-related failure modes to encompass possible risks that may exist outside of patient-based effects. Between both types of microsphere products, 173 failure mode/effect pairs were identified: 90 for patients, 35 for staff, and 48 for the institution. The SIR-Spheres program was ranked separately from the TheraSphere program because of significant differences in workflow during dose calculation, preparation, and delivery. High-ranking failure modes in each category were addressed with programmatic changes. The FMEA aided in identifying potential risk factors in our microsphere program and allowed a theoretically safer and more efficient design of the workflow and quality assurance for both our new SIR-Spheres program and our existing TheraSphere program. As new guidelines are made available, and our experience with the SIR-Spheres program increases, we will update the FMEA as an efficient starting point for future improvements. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  3. Formulation optimization of gentamicin loaded Eudragit RS100 microspheres using factorial design study.

    Science.gov (United States)

    Singh, Deependra; Saraf, Swarnlata; Dixit, Vinod Kumar; Saraf, Shailendra

    2008-04-01

    Gentamicin-Eudragit RS100 microspheres were prepared by modified double emulsion method. A 3(2) full factorial experiment was designed to study the effects of the composition of outer aqueous phase in terms of amount of glycerol (viscosity effect) and sodium chloride (osmotic pressure gradient effect) on the entrapment efficiency and % yield and microsphere size. The results of analysis of variance test for responses measured indicated that the test is significant (p>0.05). The contribution of sodium chloride concentration was found to be higher on entrapment efficiency and % yield, whereas glycerol produced significant effect on the mean diameter of microspheres. Microspheres demonstrated spherical particles in the size range of 33.24-60.43 microm. In vitro release profile of optimized formulation demonstrated sustained release for 24 h following Higuchi kinetics. Finally, drug bioactivity was found to remain intact after microencapsulation. Response surface graphs are presented to examine the effects of independent variables on the responses studied. Thus, by formulation design important parameters affecting formulation characteristics of gentamicin loaded Eudragit RS100 microspheres can be identified for controlled delivery with desirable characters in terms of maximum entrapment and yield.

  4. Adsorptive removal of an anionic dye Congo red by flower-like hierarchical magnesium oxide (MgO)-graphene oxide composite microspheres

    Science.gov (United States)

    Xu, Jing; Xu, Difa; Zhu, Bicheng; Cheng, Bei; Jiang, Chuanjia

    2018-03-01

    Flower-like magnesium oxide (MgO) microspheres and MgO-graphene oxide (GO) composites with an average diameter of 500 nm and hierarchical structure were synthesized through an ethylene glycol-mediated self-assembly process. The adsorption of Congo red (CR) by the prepared samples was evaluated in water under ambient conditions. The equilibrium adsorption isotherms of CR on the as-prepared samples could be described by the Langmuir model. The MgO-GO microspheres prepared with 0.5 wt% GO showed higher adsorption capacity (237.0 mg/g) than the MgO microspheres (227.7 mg/g). Adsorption kinetics results of CR indicated that pseudo-second-order kinetic equation could well explain the adsorption kinetics behaviors of CR. These findings indicate that the MgO-GO composite microspheres are potential adsorbents for effective removal of Congo red from wastewater.

  5. Improvement of survival in C6 rat glioma model by a sustained drug release from localized PLGA microspheres in a thermoreversible hydrogel.

    Science.gov (United States)

    Ozeki, Tetsuya; Kaneko, Daiki; Hashizawa, Kosuke; Imai, Yoshihiro; Tagami, Tatsuaki; Okada, Hiroaki

    2012-05-10

    A local drug delivery system based on sustained drug release is an attractive approach to treat brain tumors. We have developed a novel device using drug-incorporated poly(lactic-co-glycolic acid) (PLGA) microspheres embedded in thermoreversible gelation polymer (TGP) formulation (drug/PLGA/TGP formulation). TGP forms a gel at body temperature but sol at room temperature. Therefore, when this formulation is injected into the brain tumor, the PLGA microspheres in TGP gel are localized at the injection site and do not diffuse throughout the brain tissue; eventually, sustained drug release from PLGA microspheres is achieved at the target site. In this study, two chemotherapeutic drugs (camptothecin (CPT) or vincristine (VCR)) were incorporated into PLGA microspheres to prepare drug/PLGA/TGP formulations. VCR/PLGA microspheres exhibited the higher encapsulation efficiency than CPT/PLGA microspheres (70.1% versus 30.1%). In addition, VCR/PLGA microspheres showed a higher sustained release profile than CPT/PLGA microspheres (54.5% versus 72.5% release, at 28 days). Therapeutic effect (mean survival) was evaluated in the C6 rat glioma model (control group, 18 days; CPT/PLGA/TGP treatment group, 24 days; VCR/PLGA/TGP treatment group, 33 days). In particular, the VCR/PLGA/TGP formulation produced long-term survivors (>60 days). Therefore, this formulation can be therapeutically effective formulation for the glioma therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Drug-loaded poly (ε-caprolactone)/Fe3O4 composite microspheres for magnetic resonance imaging and controlled drug delivery

    Science.gov (United States)

    Wang, Guangshuo; Zhao, Dexing; Li, Nannan; Wang, Xuehan; Ma, Yingying

    2018-06-01

    In this study, poly (ε-caprolactone) (PCL) microspheres loading magnetic Fe3O4 nanoparticles and anti-cancer drug of doxorubicin hydrochloride (DOX) were successfully prepared by a modified solvent-evaporation method. The obtained magnetic composite microspheres exhibited dual features of magnetic resonance imaging and controlled drug delivery. The morphology, structure, thermal behavior and magnetic properties of the drug-loaded magnetic microspheres were investigated in detail by SEM, XRD, DSC and SQUID. The obtained composite microspheres showed superparamagnetic behavior and T2-weighted enhancement effect. The drug loading, encapsulation efficiency, releasing behavior and in vitro cytotoxicity of the drug-loaded composite microspheres were systematically investigated. It was found that the values of drug loading and encapsulation efficiency were 36.7% and 25.8%, respectively. The composite microspheres were sensitive to pH and released in a sustained way, and both the release curves under various pH conditions (4.0 and 7.4) were well satisfied with the biphase kinetics function. In addition, the magnetic response of the drug-loaded microspheres was studied and the results showed that the composite microspheres had a good magnetic stability and strong targeting ability.

  7. Surface modification of imprinted polymer microspheres with ultrathin hydrophilic shells to improve selective recognition of glutathione in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Song, Renyuan, E-mail: songrenyuan0726@163.com; Hu, Xiaoling; Guan, Ping; Li, Ji; Du, Chunbao; Qian, Liwei; Wang, Chaoli

    2016-03-01

    A universal, effective approach addressing the classical limitations of hydrophobic molecularly imprinted polymer (MIP) microspheres was described. Two water-compatible MIP microspheres with ultrathin hydrophilic shells were synthesized by controllable surface-graft polymerization using a charged monomer (methacrylic acid) and uncharged monomer (N-isopropylacrylamide) as the hydrophilic functional monomers for the recognition of glutathione in the aqueous medium. The morphological and chemical characteristics of the as-prepared water-compatible MIP microspheres were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle measurements. Their selective recognition properties were investigated by static binding tests and compared with those of the ungrafted MIP microspheres. The results of this study showed that the both as-prepared water-compatible MIP microspheres effectively decreased non-specific binding and enhanced the imprinting factor significantly, and the water-compatible MIP microspheres prepared using N-isopropylacrylamide as monomer exhibited a more remarkable recognition property. In addition, the thickness of surface-grafted hydrophilic layer was well controlled by adjusting the irradiation time to obtain the excellent recognition property. Finally, the applicability of the as-prepared water-compatible MIP microspheres as solid-phase extraction materials was investigated by competitive binding tests using a mixture of glutathione and its analogs. - Highlights: • Ultrathin hydrophilic shell was synthesized by controllable SIP approach. • Low nonspecific binding, high imprinting factor and selectivity were achieved. • Value of imprinting factor was controlled by adjusting irradiation time. • Selective solid-phase extraction of glutathione from a mixed solution of peptides.

  8. Spherical and polygonal shape of Au nanoparticles coated functionalized polymer microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Li, Yingzhi; Zhang, Junxian; Qi, Yalong; Zhao, Xin; Zhang, Qinghua, E-mail: qhzhang@dhu.edu.cn

    2015-08-01

    Highlights: • PS/PPy with well-defined core/shell structures was prepared in aqueous solution. • Au NPs were coated on PS/PPy by the fixation and continuous growth process. • Mercapto-groups played a role in the number and morphology of Au shell. • PS/PPy/Au had homogeneous and dense Au coatings with different shape. - Abstract: Uniform polystyrene (PS)/polypyrrole (PPy) composite microspheres with well-defined core/shell structures are synthesized by chemical oxidative polymerization. Gold nanoparticles (Au NPs) are successfully coated on the surface of PS/PPy microspheres by means of electrostatic interactions due to the functionalized PPy coatings supplying sufficient amino groups and the additive of mercapto acetic acid. Furthermore, the as-prepared PS/PPy/Au microspheres serving as seeds facilitate Au NPs further growth by in situ reduction in HAuCl{sub 4} solution to obtain PS/PPy/Au spheres with the core/shell/shell structure. Morphology observation demonstrates that the monodisperse PS/PPy/Au microspheres compose of uniform cores and the compact coatings containing distinct two layers. X-ray diffraction and X-ray photoelectron spectroscope confirm the existence of PPy and Au on the surface of the composite spheres. This facile approach to preparing metal-coated polymer spheres supplies the potential applications in biosensors, electronics and medical diagnosis.

  9. Enhanced in vitro dissolution of Iloperidone using Caesalpinia Pulcherrima mucoadhesive microspheres

    Directory of Open Access Journals (Sweden)

    Pradum Pundlikrao Ige

    2015-03-01

    Full Text Available The aim of the present investigation was to improve the solubility and dissolution rate of Iloperidone. Microspheres containing Iloperidone were prepared by spray drying using mucilage extracted from seeds of Caesalpinia pulcherrima. The novelty of this work is that, the extraction of mucilage and its usage for preparation of drug loaded microspheres. The prepared microspheres were characterized by SEM, DSC, XRPD, FTIR, 1H-NMR, particle size, drug content, entrapment efficiency, in vitro dissolution and ex vivo mucoadhesion. Based on particle size, drug content, ex vivo mucoadhesive strength and in vitro drug release, the best formulation was optimized. Percent entrapment efficiency and mean particle size for optimized formulation was found to be 73.49 and 3.27 ± 1.23 μm, respectively. More precisely, mucilage of C. pulcherrima could be significant carrier of (drug and polymer ratio 1:5 microspheres for the development of oral drug delivery.

  10. Synthesis of plastic scintillation microspheres: Evaluation of scintillators

    International Nuclear Information System (INIS)

    Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

    2013-01-01

    The use of plastic scintillation microspheres (PSm) appear to be an alternative to liquid scintillation for the quantification of alpha and beta emitters because it does not generate mixed wastes after the measurement (organic and radioactive). In addition to routine radionuclide determinations, PSm can be used for further applications, e.g. for usage in a continuous monitoring equipment, for measurements of samples with a high salt concentration and for an extractive scintillation support which permits the separation, pre-concentration and measurement of the radionuclides without additional steps of elution and sample preparation. However, only a few manufacturers provide PSm, and the low number of regular suppliers reduces its availability and restricts the compositions and sizes available. In this article, a synthesis method based on the extraction/evaporation methodology has been developed and successfully used for the synthesis of plastic scintillation microspheres. Seven different compositions of plastic scintillation microspheres have been synthesised; PSm1 with polystyrene, PSm2 with 2,5-Diphenyloxazol(PPO), PSm3 with p-terphenyl (pT), PSm4 with PPO and 1,4-bis(5-phenyloxazol-2-yl) (POPOP), PSm5 pT and (1,4-bis [2-methylstyryl] benzene) (Bis-MSB), PSm6 with PPO, POPOP and naphthalene and PSm7 with pT, Bis-MSB and naphthalene. The synthesised plastic scintillation microspheres have been characterised in terms of their morphology, detection capabilities and alpha/beta separation capacity. The microspheres had a median diameter of approximately 130 μm. Maximum detection efficiency values were obtained for the PSm4 composition as follows 1.18% for 3 H, 51.2% for 14 C, 180.6% for 90 Sr/ 90 Y and 76.7% for 241 Am. Values of the SQP(E) parameter were approximately 790 for PSm4 and PSm5. These values show that the synthesised PSm exhibit good scintillation properties and that the spectra are at channel numbers higher than in commercial PSm. Finally, the addition

  11. Physicochemical characterization of spray-dried PLGA/PEG microspheres, and preliminary assessment of biological response.

    Science.gov (United States)

    Javiya, Curie; Jonnalagadda, Sriramakamal

    2016-09-01

    The use of spray-drying to prepare blended PLGA:PEG microspheres with lower immune detection. To study physical properties, polymer miscibility and alveolar macrophage response for blended PLGA:PEG microspheres prepared by a laboratory-scale spray-drying process. Microspheres were prepared by spray-drying 0-20% w/w ratios of PLGA 65:35 and PEG 3350 in dichloromethane. Particle size and morphology was studied using scanning electron microscopy. Polymer miscibility and residual solvent levels evaluated by thermal analysis (differential scanning calorimetry - DSC and thermogravimetric analysis - TGA). Immunogenicity was assessed in vitro by response of rat alveolar macrophages (NR8383) by the MTT-based cell viability assay and reactive oxygen species (ROS) detection. The spray dried particles were spherical, with a size range of about 2-3 µm and a yield of 16-60%. Highest yield was obtained at 1% PEG concentration. Thermal analysis showed a melting peak at 59 °C (enthalpy: 170.61 J/g) and a degradation-onset of 180 °C for PEG 3350. PLGA 65:35 was amorphous, with a Tg of 43 °C. Blended PLGA:PEG microspheres showed a delayed degradation-onset of 280 °C, and PEG enthalpy-loss corresponding to 15% miscibility of PEG in PLGA. NR8383 viability studies and ROS detection upon exposure to these cells suggested that blended PLGA:PEG microspheres containing 1 and 5% PEG are optimal in controling cell proliferation and activation. This research establishes the feasibility of using a spray-drying process to prepare spherical particles (2-3 µm) of molecularly-blended PLGA 65:35 and PEG 3350. A PEG concentration of 1-5% was optimal to maximize process yield, with minimal potential for immune detection.

  12. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Erah

    High drug/polymer ratio, low processing temperature and low HLB value of ... Keywords: Microsphere, Emulsion solvent evaporation, Theophylline, Temperature, ... evaporation, stirring rate, viscosity of ... organic solvent is removed from the.

  13. Production of microspheres labeled with holmium-166 for liver cancer therapy: the preliminary experience at IPEN/CNEN-SP

    International Nuclear Information System (INIS)

    Costa, Renata F.; Azevedo, Mariangela B.M.; Nascimento, Nanci; Sene, Frank F.; Martinelli, Jose R.; Osso Junior, Joao A.

    2009-01-01

    Microspheres labeled with therapeutic radionuclides for malignancies of liver are widely used in many countries. The internal radionuclide therapy uses a permanently implanted device, such as Therasphere R or SIR-Spheres R , or a biodegradable device that provides structural support for the radionuclide of choice and causes the tumor reduction. Three different types of material supports have been investigated, i.e., biodegradable polymer-based, glass-based and resin-based microspheres. Nowadays there is a project concerning the labeling of these 3 materials with 166 Ho being developed at IPEN-CNEN/SP and coordinated by the Radiopharmacy Directory. 166 Ho(t 1/2 =26.8 h) is a beta minus emitter (E max =1.84 MeV), with right properties for radiotherapy and can be produced with the low power Brazilian Nuclear Reactor IEA-R1m. The aim of this work is to describe the stage of development of this project. The initial experience used resin-based microspheres, a cation exchange resin labeled with 166 Ho, it showed the essential characteristics for liver therapy. Preliminary results of the preparation of glass-based microspheres labeled with 165 Ho showed that 5% of Ho 2 O 3 was incorporated in an aluminosilicate glass, through the process of spheronization by flame, which produced spherical microspheres with 20-40μm particle size. The preparation of biodegradable material, polymer-based microspheres, is in its initial stage and the objective is to prepare and label with 165 Ho different polymer-based microspheres. These combined efforts have been done to offer a national radiotherapeutic product for the the Brazilian nuclear medicine community at fair value and also to offer a viable possibility of treatment for patients affected by liver malignancies. (author)

  14. Production of microspheres labeled with holmium-166 for liver cancer therapy: the preliminary experience at IPEN/CNEN-SP

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Renata F.; Azevedo, Mariangela B.M.; Nascimento, Nanci; Sene, Frank F.; Martinelli, Jose R.; Osso Junior, Joao A., E-mail: renatafcosta@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Microspheres labeled with therapeutic radionuclides for malignancies of liver are widely used in many countries. The internal radionuclide therapy uses a permanently implanted device, such as Therasphere{sup R} or SIR-Spheres{sup R}, or a biodegradable device that provides structural support for the radionuclide of choice and causes the tumor reduction. Three different types of material supports have been investigated, i.e., biodegradable polymer-based, glass-based and resin-based microspheres. Nowadays there is a project concerning the labeling of these 3 materials with {sup 166}Ho being developed at IPEN-CNEN/SP and coordinated by the Radiopharmacy Directory. {sup 166}Ho(t{sub 1/2}=26.8 h) is a beta minus emitter (E{sub max}=1.84 MeV), with right properties for radiotherapy and can be produced with the low power Brazilian Nuclear Reactor IEA-R1m. The aim of this work is to describe the stage of development of this project. The initial experience used resin-based microspheres, a cation exchange resin labeled with {sup 166}Ho, it showed the essential characteristics for liver therapy. Preliminary results of the preparation of glass-based microspheres labeled with {sup 165}Ho showed that 5% of Ho{sub 2}O{sub 3} was incorporated in an aluminosilicate glass, through the process of spheronization by flame, which produced spherical microspheres with 20-40mum particle size. The preparation of biodegradable material, polymer-based microspheres, is in its initial stage and the objective is to prepare and label with {sup 165}Ho different polymer-based microspheres. These combined efforts have been done to offer a national radiotherapeutic product for the the Brazilian nuclear medicine community at fair value and also to offer a viable possibility of treatment for patients affected by liver malignancies. (author)

  15. One-step growth of nanosheet-assembled BiOCl/BiOBr microspheres for highly efficient visible photocatalytic performance

    Science.gov (United States)

    Zhang, Jinfeng; Lv, Jiali; Dai, Kai; Liang, Changhao; Liu, Qi

    2018-02-01

    In this work, we have developed a simple synthetic approach of nanosheet-assembled BiOCl/BiOBr microspheres by an ethylene glycol (EG)-assisted hydrothermal method. The crystalline form, morphology, chemical composition, optical performance and surface area of BiOCl/BiOBr microspheres were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS) analysis, high resolution X-ray photoelectron spectra (XPS) and N2 adsorption-desorption isotherms. BiOCl/BiOBr microspheres were nanosheet-assembled particles, which possessed visible light absorption under LED light irridation. Additionally, the methylene blue (MB) photodegradation performance of different BiOCl/BiOBr microspheres irradiated under 410 nm LED light arrays were investigated, the results exhibited that as-prepared BiOCl/BiOBr products showed higher catalytic effiency than pure BiOCl or BiOBr. By optimizing the composition ration of the BiOCl and BiOBr, up to 93% degradation rate can be obtained in the 40%BiOCl/BiOBr microspheres. Finally, the photocatalytic mechanism of BiOCl/BiOBr microspheres had been proposed.

  16. Hollow reduced graphene oxide microspheres as a high-performance anode material for Li-ion batteries

    International Nuclear Information System (INIS)

    Mei, Riguo; Song, Xiaorui; Hu, Yan; Yang, Yanfeng; Zhang, Jingjie

    2015-01-01

    Hollow reduced graphene oxide (RGO) microspheres are successfully synthesized in large quantities through spray-drying suspension of graphene oxide (GO) nanosheets and subsequent carbothermal reduction. With this new procedure, blighted-microspherical GO precursor is synthesized through the process of spray drying, afterwards the GO precursor is subsequently calcined at 800 °C for 5 h to obtain hollow RGO microspheres. A series of analyses, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) are performed to characterize the structure and morphology of intermediates and as-obtained product. The as-obtained hollow RGO microspheres provide a high specific surface area (175.5 m 2 g −1 ) and excellent electronic conductivity (6.3 S cm −1 ), and facilitated high electrochemical performance as anode material for Li-ion batteries (LIBs). Compared with the RGO nanosheets, the as-obtained hollow RGO microspheres exhibit superior specific capacity and outstanding cyclability. In addition, this spray drying and carbothermal reduction (SDCTR) method provided a facile route to prepare hollow RGO microspheres in large quantities

  17. An investigation into the effects of residual water on the glass transition temperature of polylactide microspheres using modulated temperature DSC.

    Science.gov (United States)

    Passerini, N; Craig, D Q

    2001-05-18

    The objective of the study was to ascertain residual water levels in polylactide and polylactide-co-glycolide microspheres prepared using the solvent evaporation technique and to investigate the effects of that water on the glass transitional behaviour of the microspheres. Microspheres were prepared from polylactic acid (PLA) and polylactide-co-glycolide (PLGA) 50:50 and 75:25 using a standard solvent evaporation technique. The glass transition was measured as a function of drying conditions using modulated temperature DSC. The microspheres were found to contain very low levels of dichloromethane, while residual water levels of up to circa 3% w/w were noted after freeze or oven drying, these levels being higher for microspheres containing higher glycolic acid levels. The residual water was found to lower the T(g) following the Gordon-Taylor relationship. The data indicate that the microparticles may retain significant water levels following standard preparation and drying protocols and that this drying may markedly lower the T(g) of the spheres.

  18. Aluminum-Doped SnO2 Hollow Microspheres as Photoanode Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Binghua Xu

    2016-01-01

    Full Text Available Al doped SnO2 microspheres were prepared through hydrothermal method. As-prepared SnO2 microspheres were applied as photoanode materials in dye-sensitized solar cells (DSCs. The properties of the assembled DSCs were significantly improved, especially the open-circuit voltage. The reason for the enhancement was explored through the investigation of dark current curves and electrochemistry impedance spectra. These results showed that the Al doping significantly increased the reaction resistance of recombination reactions and restrained the dark current. The efficient lifetime of photoexcited electrons was also obviously lengthened.

  19. A facile approach to fabricate of photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Baolong; Shan, Yan, E-mail: shanyan@qust.edu.cn; Chen, Kezheng, E-mail: kchen@qust.edu.cn

    2017-06-01

    Photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres have been prepared successfully by a simple chemical deposition method. The adsorption of cetyltrimethyl-ammonium bromide (CTAB) on the magnetic microspheres plays an important role in forming the structure of the composites. The present materials are characterized with XRD, TEM, SEM, FTIR, and UV-VIS-NIR spectrophotometer. The results show that Fe{sub 3}O{sub 4} microspheres are coated by CuS layer with thickness of 10 nm. The saturation magnetization value of Fe{sub 3}O{sub 4}@CuS core-shell microspheres is 27 emu/g at room temperature and the sample possesses excellent magnetic response in the presence of applied magnetic field. Moreover, these microspheres exhibit good dispersion, suitable size and significant photothermal conversion efficiency up to 20.7% at 808 nm laser irradiation. Fluctuation value of the highest temperature of Fe{sub 3}O{sub 4}@CuS dispersion over four times LASER ON/OFF indicates that photothermal stability of Fe{sub 3}O{sub 4}@CuS microspheres is good. - Highlights: • The Fe{sub 3}O{sub 4} microspheres have been coated with CuS and the thickness of CuS layer is about 10 nm. • The Fe{sub 3}O{sub 4}@CuS microspheres are ferromagnetism, and possess good photothermal conversion efficiency and photostability. • The materials have great potential application for photothermal therapy.

  20. Formulation, optimization, and pharmacodynamic evaluation of chitosan/phospholipid/β-cyclodextrin microspheres

    Directory of Open Access Journals (Sweden)

    Shan L

    2016-01-01

    Full Text Available Lu Shan,1 En-Xue Tao,2 Qing-Hui Meng,3 Wen-Xia Hou,3 Kang Liu,1 Hong-Cai Shang,4 Jin-Bao Tang,1 Wei-Fen Zhang1,4 1School of Pharmacy, Weifang Medical University, 2The Affiliated Hospital of Weifang Medical University, 3School of Nursing, Weifang Medical University, Weifang, 4Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, People’s Republic of China Abstract: Cholinergic neurotransmission loss is the main cause of cognitive impairment in patients with Alzheimer’s disease. Phospholipids (PLs play an essential role in memory and learning abilities. Moreover, PLs act as a source of choline in acetylcholine synthesis. This study aimed to prepare and optimize the formulation of chitosan/phospholipid/β-cyclodextrin (CTS/PL/β-CD microspheres that can improve cognitive impairment. The CTS/PL/β-CD microspheres were prepared by spray drying, and optimized with an orthogonal design. These microspheres were also characterized in terms of morphology, structure, thermostability, drug loading, and encapsulation efficiency. The spatial learning and memory of rats were evaluated using the Morris water maze test, and the neuroprotective effects of the CTS/PL/β-CD microspheres were investigated by immunohistochemistry. Scanning electron microscopic images showed that the CTS/PL/β-CD microspheres were spherical with slightly wrinkled surfaces. Fourier transform infrared spectroscopy and differential scanning calorimetry proved that PLs formed hydrogen bonds with the amide group of CTS and the hydroxyl group of β-CD. The learning and memory abilities of rats in the treated group significantly improved compared with those in the model group. Immunohistochemical analysis revealed that treatment with the CTS/PL/β-CD microspheres attenuated the expression of protein kinase C-δ and inhibited the activation of microglias. These results suggest that the

  1. Fiber-optic array using molecularly imprinted microspheres for antibiotic analysis.

    Science.gov (United States)

    Carrasco, Sergio; Benito-Peña, Elena; Walt, David R; Moreno-Bondi, María C

    2015-05-01

    In this article we describe a new class of high-density optical microarrays based on molecularly imprinted microsphere sensors that directly incorporate specific recognition capabilities to detect enrofloxacin (ENRO), an antibiotic widely used for both human and veterinary applications. This approach involves the preparation of highly cross-linked polymer microspheres by thermal precipitation-polymerization in the presence and absence of the target analyte ENRO to generate either molecularly imprinted (MIP) or non-imprinted polymer (NIP) microspheres, respectively. Each polymer type of tailor-made microsphere is fluorescently encoded with either coumarin-30 or tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(ii) dichloride [Ru(dip) 3 ]Cl 2 to enable the microspheres to be distinguished. The new MIP-based sensing platform utilizes an optical fiber bundle containing approximately 50 000 individual 3.1 μm diameter fibers that are chemically etched to create microwells in which MIP and NIP microspheres can be deposited and imaged using an epi-fluorescence microscope. The method enables multiplexed detection by independently addressing both types of beads through their separate light channels. The unique response to the presence of ENRO is manifested on the basis of a competitive immunoassay. A red-fluorescent dye-tagged ENRO, labeled with BODIPY® TR Cadaverine, competes with ENRO for specific binding sites. The developed immuno-like assay displayed a limit of detection (LOD) of 0.04 μM (10% binding inhibition) and a dynamic range of 0.29-21.54 μM (20-80% binding inhibition). The selectivity of the assay was evaluated by measuring the cross-reactivity of other fluoroquinolones (ciprofloxacin, norfloxacin, danofloxacin, and flumequine) and non-related antibiotics (penicillin G and doxycycline). This work demonstrates, for the first time, the applicability of MIPs, as an alternative to biomolecule receptors, for the development of multiplexed detection fiber

  2. Facile Fabrication of Urchin-like Polyaniline Microspheres for Electrochemical Energy Storage

    International Nuclear Information System (INIS)

    Wang, Yuan; Xu, Shaoqin; Liu, Wenfeng; Cheng, Huan; Chen, Shaoyun; Liu, Xueqing; Liu, Jiyan; Tai, Qidong; Hu, Chenglong

    2017-01-01

    Graphical abstract: The urchin-like polyaniline (i.e. PANI) microsphere was polymerized using the sulfonated polystyrene microspheres (i.e. SPS) as template. It showed large specific capacitance of 435 F g −1 at a scan rate of 10 mV s −1 , and also exhibited the good rate capability and the cycling stability with capacitance retentions of 93% after 1000 cycles. This facile approach is feasible and easy to fabricate microstructural conducting polymer for supercapacitor electrode materials. Display Omitted -- Highlights: •A novel route to fabricate urchin-like polyaniline (PANI) by polymeric template. •The specific capacitance of 435 Fg 1 was obtained when PANI acted as the electrode. •The cycling stability with capacitance retentions of 93% after 1000 cycles. -- Abstract: The urchin-like polyaniline (i.e. PANI) microsphere was polymerized using the sulfonated polystyrene microsphere (i.e. SPS) as template, and its structure was successfully conformed by the X-ray photoelectron spectrum, Raman spectrum, Ultraviolet-visible spectrum, and TGA thermogram. The urchin-like PANI microspheres with uniform diameter (1.5 μm) can be observed on scanning electron microscopy (SEM). Cyclic voltammetry and galvanostatic charge/discharge tests were carried out to investigate the electrochemical properties of as-prepared urchin-like PANI microspheres. It showed that the specific capacitance (SC) was 435 Fg −1 at a scan rate of 10 mV s −1 , and also exhibited good capability and cycling stability with capacitance retentions of 93% after 1000 cycles, which is superior or close to some individual PANI nanostructures and PANI composite materials. This facile approach is feasible and easy to fabricate microstructural conducting polymer for supercapacitor electrode materials.

  3. Strain-tuned optoelectronic properties of hollow gallium sulphide microspheres

    Science.gov (United States)

    Zhang, Yin; Chen, Chen; Liang, C. Y.; Liu, Z. W.; Li, Y. S.; Che, Renchao

    2015-10-01

    Sulfide semiconductors have attracted considerable attention. The main challenge is to prepare materials with a designable morphology, a controllable band structure and optoelectronic properties. Herein, we report a facile chemical transportation reaction for the synthesis of Ga2S3 microspheres with novel hollow morphologies and partially filled volumes. Even without any extrinsic dopant, photoluminescence (PL) emission wavelength could be facilely tuned from 635 to 665 nm, depending on its intrinsic inhomogeneous strain distribution. Geometric phase analysis (GPA) based on high-resolution transmission electron microscopy (HRTEM) imaging reveals that the strain distribution and the associated PL properties can be accurately controlled by changing the growth temperature gradient, which depends on the distance between the boats used for raw material evaporation and microsphere deposition. The stacking-fault density, lattice distortion degree and strain distribution at the shell interfacial region of the Ga2S3 microspheres could be readily adjusted. Ab initio first-principles calculations confirm that the lowest conductive band (LCB) is dominated by S-3s and Ga-4p states, which shift to the low-energy band as a result of the introduction of tensile strain, well in accordance with the observed PL evolution. Therefore, based on our strain driving strategy, novel guidelines toward the reasonable design of sulfide semiconductors with tunable photoluminescence properties are proposed.Sulfide semiconductors have attracted considerable attention. The main challenge is to prepare materials with a designable morphology, a controllable band structure and optoelectronic properties. Herein, we report a facile chemical transportation reaction for the synthesis of Ga2S3 microspheres with novel hollow morphologies and partially filled volumes. Even without any extrinsic dopant, photoluminescence (PL) emission wavelength could be facilely tuned from 635 to 665 nm, depending on its

  4. Enhanced microwave absorption properties of MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Han, Bingqian; Chen, Nan; Deng, Dongyang; Guan, Hongtao [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Wang, Yude, E-mail: ydwang@ynu.edu.cn [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Yunnan Province Key Lab of Micro-Nano Materials and Technology, Yunnan University, 650091, Kunming (China)

    2016-08-15

    MnO{sub 2} hollow microspheres consisted of nanoribbons were successfully fabricated via a facile hydrothermal method with SiO{sub 2} sphere templates. The crystal structure, morphology and microwave absorption properties in X and Ku band of the as-synthesized samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and a vector network analyzer. The results show that the three-dimensional (3D) hollow microspheres are assembled by ultra thin and narrow one-dimensional (1D) nanoribbons. A rational process for the formation of hollow microspheres is proposed. The 3D MnO{sub 2} hollow microspheres possess improved dielectric and magnetic properties than the 1D nanoribbons prepared by the same procedures with the absence of SiO{sub 2} hard templates, which are closely related to their special nanostructures. The MnO{sub 2} microspheres also show much better microwave absorption properties in X (8–12 GHz) and Ku (12–18 GHz) microwave band compared with 1D MnO{sub 2} nanoribbons. The minimum reflection loss of −40 dB for hollow microsphere can be observed at 14.2 GHz and reflection loss below −10 dB is 3.5 GHz with a thickness of only 4 mm. The possible mechanism for the enhanced microwave absorption properties is also discussed. - Graphical abstract: MnO{sub 2} hollow microspheres composed of nanoribbons show the excellent microwave absorption properties in X and Ku band. - Highlights: • MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons were successfully prepared. • MnO{sub 2} hollow microspheres possess good microwave absorption performances. • The excellent microwave absorption properties are in X and Ku microwave band. • Electromagnetic impedance matching is great contribution to absorption properties.

  5. Hollow TiO2 modified reduced graphene oxide microspheres encapsulating hemoglobin for a mediator-free biosensor.

    Science.gov (United States)

    Liu, Hui; Guo, Kai; Duan, Congyue; Dong, Xiaonan; Gao, Jiaojiao

    2017-01-15

    Hollow TiO 2 modified reduced graphene oxide microspheres (hollow TiO 2 -rGO microspheres or H-TiO 2 -rGO MS) have been synthesized and then be used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of hollow TiO 2 -rGO microspheres were characterized by scanning electron microscopy, transmission electronic microscopy and X-ray diffraction. Results of spectroscopy and electrochemistry tests revealed that hollow TiO 2 -rGO microsphere is an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. The hollow TiO 2 -rGO microspheres with special structure and component enhance the immobilization efficiency of proteins and facilitate the direct electron transfer, which result in the better H 2 O 2 detection performance-the wide linear range of 0.1-360μM for H 2 O 2 (sensitivity of 417.6 μA mM -1 cm -2 ) and the extremely low detection limit of 10nM for H 2 O 2 . Moreover, the hollow microsphere can provide a protective microenvironment for Hb to make the as-prepared biosensor improve long-term stability. The as-prepared biosensor retains 95.4% of the initial response to H 2 O 2 after 60-d storage. Hence, this work suggests that if can be fabricated a mediator-free biosensor, hollow TiO 2 -rGO microspheres will find wide potential applications in environmental analysis and biomedical detection. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. DEGRADATION AND INTRAHEPATIC COMPATIBILITY OF ALBUMIN-HEPARIN CONJUGATE MICROSPHERES

    NARCIS (Netherlands)

    CREMERS, HFM; WOLF, RFE; BLAAUW, EH; SCHAKENRAAD, JM; LAM, KH; NIEUWENHUIS, P; VERRIJK, R; KWON, G; BAE, YH; KIM, SW; FEIJEN, J

    The in vitro degradation properties of glutaraldehyde cross-linked albumin and albumin-heparin conjugate microspheres (AMS and AHCMS respectively) were evaluated using light microscopy, turbidity measurements and heparin release determinations, showing that the microspheres are degraded by

  7. Use of Novel Polyurethane Microspheres in a Curcumin Delivery System

    Directory of Open Access Journals (Sweden)

    Yongmei Hu

    2014-01-01

    Full Text Available Despite having a wide range of beneficial pharmacological effects, curcumin is characterized by poor water solubility and absorption. In this study, novel polyurethane microspheres containing curcumin (Cur-PUMs were prepared using carboxymethyl cellulose sodium to improve the bioavailability and prolong the retention time of curcumin. The prepared Cur-PUMs were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, and ultraviolet spectrophotometer. The sustained-release effects of Cur-PUMs were demonstrated using stability tests in vitro and in vivo pharmacokinetic studies following oral administration. We found that the stability of Cur-PUMs was strongly affected by pH variation. Further, compared with free curcumin, Cur-PUMs showed significantly improved maximum concentration and half-life.

  8. Lead recovery and glass microspheres synthesis from waste CRT funnel glasses through carbon thermal reduction enhanced acid leaching process.

    Science.gov (United States)

    Mingfei, Xing; Yaping, Wang; Jun, Li; Hua, Xu

    2016-03-15

    In this study, a novel process for detoxification and reutilization of waste cathode ray tube (CRT) funnel glass was developed by carbon thermal reduction enhanced acid leaching process. The key to this process is removal of lead from the CRT funnel glass and synchronous preparation of glass microspheres. Carbon powder was used as an isolation agent and a reducing agent. Under the isolation of the carbon powder, the funnel glass powder was sintered into glass microspheres. In thermal reduction, PbO in the funnel glass was first reduced to elemental Pb by carbon monoxide and then located on the surface of glass microspheres which can be removed easily by acid leaching. Experimental results showed that temperature, carbon adding amount and holding time were the major parameters that controlled lead removal rate. The maximum lead removal rate was 94.80% and glass microspheres that measured 0.73-14.74μm were obtained successfully by setting the temperature, carbon adding amount and holding time at 1200°C, 10% and 30min, respectively. The prepared glass microspheres may be used as fillers in polymer materials and abrasive materials, among others. Accordingly, this study proposed a practical and economical process for detoxification and recycling of waste lead-containing glass. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Song, Kedong; Liu, Yingchao; Macedo, Hugo M; Jiang, Lili; Li, Chao; Mei, Guanyu; Liu, Tianqing

    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(-2) mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique

  10. Flexible Microsphere-Embedded Film for Microsphere-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Xing, Cheng; Yan, Yinzhou; Feng, Chao; Xu, Jiayu; Dong, Peng; Guan, Wei; Zeng, Yong; Zhao, Yan; Jiang, Yijian

    2017-09-27

    Dielectric microspheres with extraordinary microscale optical properties, such as photonic nanojets, optical whispering-gallery modes (WGMs), and directional antennas, have drawn interest in many research fields. Microsphere-enhanced Raman spectroscopy (MERS) is an alternative approach for enhanced Raman detection by dielectric microstructures. Unfortunately, fabrication of microsphere monolayer arrays is the major challenge of MERS for practical applications on various specimen surfaces. Here we report a microsphere-embedded film (MF) by immersing a highly refractive microsphere monolayer array in the poly(dimethylsiloxane) (PDMS) film as a flexible MERS sensing platform for one- to three-dimensional (1D to 3D) specimen surfaces. The directional antennas and wave-guided whispering-gallery modes (WG-WGMs) contribute to the majority of Raman enhancement by the MFs. Moreover, the MF can be coupled with surface-enhanced Raman spectroscopy (SERS) to provide an extra >10-fold enhancement. The limit of detection is therefore improved for sensing of crystal violet (CV) and Sudan I molecules in aqueous solutions at concentrations down to 10 -7 M. A hybrid dual-layer microsphere enhancer, constructed by depositing a MF onto a microsphere monolayer array, is also demonstrated, wherein the WG-WGMs become dominant and boost the enhancement ratio >50-fold. The present work opens up new opportunities for design of cost-effective and flexible MERS sensing platforms as individual or associated techniques toward practical applications in ultrasensitive Raman detection.

  11. The Complex Sol–Gel Process for producing small ThO{sub 2} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Brykala, Marcin, E-mail: m.brykala@ichtj.waw.pl; Rogowski, Marcin

    2016-05-15

    Thorium based fuels offer several benefits compared to uranium based fuels thus they might be an attractive alternative to conventional fuel types. This study is devoted to the synthesis and the characterization of small thorium dioxide microspheres (Ø <50 μm). Their application involves using powder-free process, called the Complex Sol–Gel Process. The source sols used for the processes were prepared by the method where in the starting ascorbic acid solution the solid thorium nitrate was dissolved and partially neutralized by aqueous ammonia under pH control. The microspheres of thorium-ascorbate gel were obtained using the ICHTJ Process (INCT in English). Studies allowed to determine an optimal heat treatment with calcination temperature of 700 °C and temperature rate not higher than 2 °C/min which enabled us to obtain a crack-free surface of microspheres. The main parameters which have a strong influence on the synthesis method and features of the spherical particles of thorium dioxide are described in this article. - Highlights: • ThO{sub 2} were prepared for the first time using combination of ICHTJ methods. • The homogeneous thorium-ascorbate sol was used as starting solutions in CSGP method. • The gelation by IChTJ Process to microspheres (Ø <50 μm) with 100% efficiency was used. • ThO{sub 2} microspheres exhibit a high sphericity, crack-free surface and microstructure. • The cubic crystalline structure of ThO{sub 2} was produced at 700 °C.

  12. Biocompatibility of Bletilla striata Microspheres as a Novel Embolic Agent

    Directory of Open Access Journals (Sweden)

    ShiHua Luo

    2015-01-01

    Full Text Available We have prepared Chinese traditional herb Bletilla striata into microspheres as a novel embolic agent for decades. The aim of this study was to evaluate the biocompatibility of Bletilla striata microspheres (BSMs. After a thermal test of BSMs in vitro, the cell biocompatibility of BSMs was investigated in mouse fibroblasts and human umbilical vein endothelial cells using the methyl tetrazolium (MTT assay. In addition, blood biocompatibility was evaluated. In vivo intramuscular implantation and renal artery embolization in rabbits with BSMs were used to examine the inflammatory response. The experimental rabbits did not develop any fever symptoms after injection of BSMs, and BSMs exhibited no cytotoxicity in cultured mouse fibroblasts and human umbilical vein endothelial cells. Additionally, BSMs exhibited high compatibility with red blood cells and no hemolysis activity. Intramuscular implantation with BSMs resulted in a gradually lessened mild inflammatory reaction that disappeared after eight weeks. The occlusion of small renal vessels was associated with a mild perivascular inflammatory reaction without significant renal and liver function damage. In conclusion, we believe that BSMs exhibit high biocompatibility and are a promising embolic agent.

  13. 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.

  14. 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

  15. Enhanced performance of microfluidic soft pressure sensors with embedded solid microspheres

    Science.gov (United States)

    Shin, Hee-Sup; Ryu, Jaiyoung; Majidi, Carmel; Park, Yong-Lae

    2016-02-01

    The cross-sectional geometry of an embedded microchannel influences the electromechanical response of a soft microfluidic sensor to applied surface pressure. When a pressure is exerted on the surface of the sensor deforming the soft structure, the cross-sectional area of the embedded channel filled with a conductive fluid decreases, increasing the channel’s electrical resistance. This electromechanical coupling can be tuned by adding solid microspheres into the channel. In order to determine the influence of microspheres, we use both analytic and computational methods to predict the pressure responses of soft microfluidic sensors with two different channel cross-sections: a square and an equilateral triangular. The analytical models were derived from contact mechanics in which microspheres were regarded as spherical indenters, and finite element analysis (FEA) was used for simulation. For experimental validation, sensor samples with the two different channel cross-sections were prepared and tested. For comparison, the sensor samples were tested both with and without microspheres. All three results from the analytical models, the FEA simulations, and the experiments showed reasonable agreement confirming that the multi-material soft structure significantly improved its pressure response in terms of both linearity and sensitivity. The embedded solid particles enhanced the performance of soft sensors while maintaining their flexible and stretchable mechanical characteristic. We also provide analytical and experimental analyses of hysteresis of microfluidic soft sensors considering a resistive force to the shape recovery of the polymer structure by the embedded viscous fluid.

  16. 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.

  17. Phase transformation, morphology evolution and luminescence property variation in Y2O3: Eu hollow microspheres

    International Nuclear Information System (INIS)

    Wang, Qin; Guo, Jing; Jia, Wenjing; Liu, Baocang; Zhang, Jun

    2012-01-01

    Highlights: ► We report a general and facile method for the synthesis of Y 2 O 3 : Eu hollow microspheres. ► This method may be of great significance in the synthesis of many other hollow spherical materials. ► Phase, morphology and luminescence property were found to be strongly dependent on temperature and pH. ► The evolution process under various temperatures and pH values were discussed. ► The sample shows a strong red emission under short UV irradiation, and the lifetime is determined to be 7.0 ms. - Abstract: Y 2 O 3 : Eu hollow microspheres with average size of 500–600 nm have been successfully synthesized via a solvothermal method in the presence of sodium citrate as surfactant followed by a subsequent heat treatment process. High polymer F127(EO 106 PO 70 EO 106 ) served as a soft template in the formation of as prepared hollow microspheres. It is found that the pH values and the reaction temperature are two crucial factors in determining the phase, morphology and luminescence properties of the Y 2 O 3 : Eu hollow microspheres. Morphology evolution can be achieved by changing the pH and the reaction temperature. The properties of the Eu 3+ -doped Y 2 O 3 : Eu nanocrystals were characterized by XRD, FE-SEM, HR-TEM and UV–vis spectroscopy.

  18. Investigation of the parameters affecting the release of flurbiprofen from chitosan microspheres

    Directory of Open Access Journals (Sweden)

    Müşerref Günseli Yüksel Tilkan

    2018-04-01

    Full Text Available ABSTRACT Flurbiprofen (FLB, a NSAID, widely used for preventing pain generally for arthritis or dental problems. In this study, FLB loaded chitosan microspheres were prepared by ionotropic gelation method. In this method, microspheres were formed by dropping chitosan solutions containing FLB into sodium alginate solutions including sodium tripolyphosphate (TPP. A variety of formulation parameters like drug:polymer ratio, drug concentration, polymer’s molecular weight, polymer concentration, pH and the concentration of TPP solutions, drying method and stirring time were analyzed. The dissolution studies were performed in a shaking water bath in pH 7.4 phosphate buffer saline (PBS at 37 °C. Laser diffractometer was used for particle size analysis, and scanning electron microscope (SEM was used for morphological properties. Drug loading and loading efficiency were calculated by using UV spectrophotometer. The particles obtained were spherical with 0.7-1.3 mm size range, and the loading efficiency was approximately 21-79%. The dissolution studies conducted revealed that drug:polimer ratio and the polymer type and concentration affected the drug release from microspheres. It was observed that increasing the polymer concentration, polymer’s molecular weight and TPP concentration decreased the FLB release from microspheres, which was according to Higuchi kinetics.

  19. Extraction and encapsulation of prodigiosin in chitosan microspheres for targeted drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Dozie-Nwachukwu, S.O. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Biotechnology and Genetic Engineering Advanced Laboratory, Sheda Science and Technology Complex (SHESTCO), P.M.B 186, Garki, Abuja, Federal Capital Territory (Nigeria); Danyuo, Y. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Materials Science and Engineering, Kwara State University, Malete (Nigeria); Obayemi, J.D. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Odusanya, O.S. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Biotechnology and Genetic Engineering Advanced Laboratory, Sheda Science and Technology Complex (SHESTCO), P.M.B 186, Garki, Abuja, Federal Capital Territory (Nigeria); Malatesta, K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Soboyejo, W.O., E-mail: soboyejo@princeton.edu [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Princeton Institute of Science and Technology of Materials (PRISM), Bowen Hall, 70 Prospect Street, Princeton, NJ 08544 (United States)

    2017-02-01

    The encapsulation of drugs in polymeric materials has brought opportunities to the targeted delivery of chemotherapeutic agents. These polymeric delivery systems are capable of maximizing the therapeutic activity, as well as reducing the side effects of anti-cancer agents. Prodigiosin, a secondary metabolite extracted from the bacteria, Serratia marcescens, exhibits anti-cancer properties. Prodigiosin-loaded chitosan microspheres were prepared via water-in-oil (w/o) emulsion technique, using glutaraldehyde as a cross-linker. The morphologies of the microspheres were studied using scanning electron microscopy. The average sizes of the microspheres were between 40 μm and 60 μm, while the percentage yields ranged from 42 ± 2% to 55.5 ± 3%. The resulting encapsulation efficiencies were between 66.7 ± 3% and 90 ± 4%. The in-vitro drug release from the microspheres was characterized by zeroth order, first order and Higuchi and Korsmeyer-Peppas models. - Highlights: • Prodigiosin of ~ 92.8% purity was extracted from locally isolated Serratia marcescens. • This approach reduces the cost and ensure availability of drugs for cancer treatment. • High encapsulation efficiency which increased with increasing drug:polymer ratio • The percentage yield was generally poor due to the recovery process. • Prodigiosin greatly reduced the viability of the breast cancer cell line (MDA-MB-231).

  20. Binary breath figures for straightforward and controllable self-assembly of microspherical caps.

    Science.gov (United States)

    Gong, Jianliang; Xu, Bingang; Tao, Xiaoming; Li, Lei

    2016-05-11

    The intense interest surrounding asymmetrical microparticles originates from their unique anisotropic properties and promising applications. In this work, direct self-assembly of polymeric microspherical caps without the assistance of any additives has been achieved by using low-surface-tension methanol (MeOH) and high-surface-tension water as binary breath figures (BFs). With the evaporation of polystyrene (PS) solution containing low-boiling-point solvent in the binary vapors, the formed MeOH BFs could quickly diffuse into solution, while water BFs tended to remain at the solution surface. This led to the formation of a gradient nonsolvent layer at the vapor/solution interface, which induced the formation of nuclei and guided further asymmetrical growth of polymer particles. After the spontaneous removal of MeOH, water and residual solvent by evaporation, polymeric microspherical caps were left on the substrate. Through controlling the proportion of water introduced by adjusting the ratios of MeOH and water, polymeric microspherical caps with a range of controllable shapes (divided at different positions of a sphere) were successfully obtained. The formation mechanism was explained based on the difference of vapor pressure, surface tension and miscibility between the employed solvents and nonsolvents. A solvent possessing a high vapor pressure, low surface tension and good miscibility with MeOH contributed to the formation of microspherical caps. This flexible, green and straightforward technique is a nondestructive strategy, and avoids complicated work on design, preparation and removal of hard templates and additives.

  1. Synthesis and characterization of emamectin-benzoate slow-release microspheres with different surfactants.

    Science.gov (United States)

    Wang, Yan; Wang, Anqi; Wang, Chunxin; Cui, Bo; Sun, Changjiao; Zhao, Xiang; Zeng, Zhanghua; Shen, Yue; Gao, Fei; Liu, Guoqiang; Cui, Haixin

    2017-10-06

    Pesticide slow-release formulations provide a way to increase the efficiency of active components by reducing the amount of pesticide that needs to be applied. Slow-release formulations also increase the stability and prolong the control effect of photosensitive pesticides. Surfactants are an indispensable part of pesticide formulations, and the choice of surfactant can strongly affect formulation performance. In this study, emamectin-benzoate (EMB) slow-release microspheres were prepared by the microemulsion polymerization method. We explored the effect of different surfactants on the particle size and dispersity of EMB in slow-release microspheres. The results indicated that the samples had uniform spherical shapes with an average diameter of 320.5 ±5.24 nm and good dispersity in the optimal formulation with the polymeric stabilizer polyvinyl alcohol (PVA) and composite non-ionic surfactant polyoxyethylene castor oil (EL-40). The optimal EMB pesticide slow-release microspheres had excellent anti-photolysis performance, stability, controlled release properties, and good leaf distribution. These results demonstrated that EMB slow-release microspheres are an attractive candidate for improving pesticide efficacy and prolonging the control effect of EMB in the environment.

  2. Extraction and encapsulation of prodigiosin in chitosan microspheres for targeted drug delivery

    International Nuclear Information System (INIS)

    Dozie-Nwachukwu, S.O.; Danyuo, Y.; Obayemi, J.D.; Odusanya, O.S.; Malatesta, K.; Soboyejo, W.O.

    2017-01-01

    The encapsulation of drugs in polymeric materials has brought opportunities to the targeted delivery of chemotherapeutic agents. These polymeric delivery systems are capable of maximizing the therapeutic activity, as well as reducing the side effects of anti-cancer agents. Prodigiosin, a secondary metabolite extracted from the bacteria, Serratia marcescens, exhibits anti-cancer properties. Prodigiosin-loaded chitosan microspheres were prepared via water-in-oil (w/o) emulsion technique, using glutaraldehyde as a cross-linker. The morphologies of the microspheres were studied using scanning electron microscopy. The average sizes of the microspheres were between 40 μm and 60 μm, while the percentage yields ranged from 42 ± 2% to 55.5 ± 3%. The resulting encapsulation efficiencies were between 66.7 ± 3% and 90 ± 4%. The in-vitro drug release from the microspheres was characterized by zeroth order, first order and Higuchi and Korsmeyer-Peppas models. - Highlights: • Prodigiosin of ~ 92.8% purity was extracted from locally isolated Serratia marcescens. • This approach reduces the cost and ensure availability of drugs for cancer treatment. • High encapsulation efficiency which increased with increasing drug:polymer ratio • The percentage yield was generally poor due to the recovery process. • Prodigiosin greatly reduced the viability of the breast cancer cell line (MDA-MB-231).

  3. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1995-04-18

    New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for our engineered glass microspheres is about 150,000 psi, permitting a threefold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers.

  4. Controlled-release and preserved bioactivity of proteins from (self-assembled core-shell double-walled microspheres

    Directory of Open Access Journals (Sweden)

    Yuan W

    2012-01-01

    Full Text Available Weien Yuan1,2, Zhenguo Liu11Department of Neurology, Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 2School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaAbstract: In order to address preserved protein bioactivities and protein sustained-release problems, a method for preparing double-walled microspheres with a core (protein-loaded nanoparticles with a polymer-suspended granule system-formed core and a second shell (a polymer-formed shell for controlled drug release and preserved protein bioactivities has been developed using (solid-in-oil phase-in-hydrophilic oil-in-water (S/O/Oh/W phases. The method, based on our previous microsphere preparation method (solid-in-oil phase-in-hydrophilic oil-in-water (S/O/Oh/W, employs different concentric poly(D,L-lactide-co-glycolide, poly(D,L-lactide, and protein-loaded nanoparticles to produce a suspended liquid which then self-assembles to form shell-core microspheres in the hydrophilic oil phase, which are then solidified in the water phase. Variations in the preparation parameters allowed complete encapsulation by the shell phase, including the efficient formation of a poly(D,L-lactide shell encapsulating a protein-loaded nanoparticle-based poly(D,L-lactide-co-glycolide core. This method produces core-shell double-walled microspheres that show controlled protein release and preserved protein bioactivities for 60 days. Based upon these results, we concluded that the core-shell double-walled microspheres might be applied for tissue engineering and therapy for chronic diseases, etc.Keywords: protein delivery, protein stability, core-shell microspheres, dextran nanoparticles

  5. Hydrothermal synthesis and electrochemical performance of NiO microspheres with different nanoscale building blocks

    International Nuclear Information System (INIS)

    Wang Ling; Hao Yanjing; Zhao Yan; Lai Qiongyu; Xu Xiaoyun

    2010-01-01

    NiO microspheres were successfully obtained by calcining the Ni(OH) 2 precursor, which were synthesized via the hydrothermal reaction of nickel chloride, glucose and ammonia. The products were characterized by TGA, XRD and SEM. The influences of glucose and reaction temperature on the morphologies of NiO samples were investigated. Moreover, the possible growth mechanism for the spherical morphology was proposed. The charge/discharge test showed that the as-prepared NiO microspheres composed of nanoparticles can serve as an ideal electrode material for supercapacitor due to the spherical hollow structure. -- Graphical Abstract: Fig. 5 is the SEM image of NiO that was prepared in the different hydrothermal reaction temperatures. It showed that reaction temperature played a crucial role for the morphology of products.

  6. Urchin-like TiO₂@C core-shell microspheres: coupled synthesis and lithium-ion battery applications.

    Science.gov (United States)

    Liu, Zhenyu; Liu, Jing; Liu, Junfeng; Wang, Li; Zhang, Guoxin; Sun, Xiaoming

    2014-05-21

    Carbon coated urchin-like TiO2 microspheres were prepared through coupled hydrolysis of titanium tetrachloride and catalyzed carbonization of glucose. Carbon coating endowed the composite with unusual structural stability at high temperature and reasonable Li-ion battery performance.

  7. 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.

  8. Synthesis and Evaluation of Molecularly Imprinted Polymeric Microspheres for Chloramphenicol by Aqueous Suspension Polymerization as a High Performance Liquid Chromatography Stationary Phase

    International Nuclear Information System (INIS)

    Zhang, Yan; Lei, Jiandu

    2013-01-01

    Molecularly imprinted microsphere for chloramphenicol (CAP) with high adsorption capacity and excellent selectivity is prepared by aqueous suspension polymerization, in which chloramphenicol is used as template molecule and ethyl acetate as porogen. The CAP-imprinted microspheres are used as high performance liquid chromatography (HPLC) stationary phase and packed into stainless steel column (150 mm Χ 4.6 mm i. d.) for selective separation of chloramphenicol. HPLC analysis suggests that chloramphenicol can be distinguished from not only its structural analogs but also other broad-spectrum antibiotic such as erythromycin and tetracycline. In addition, the binding experiments of CAP-imprinted microspheres are carried out in ethanol/water (1:4, V:V), the results indicate that the maximum apparent static binding capacity of molecularly imprinted microspheres is up to 66.64 mg g -1 according to scatchard model

  9. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Schlegel, P.

    1981-01-01

    Albumin microspheres have been synthesized with 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 24 hr in 50% plasma at 37 0 C, whereas with DTPA microspheres the label shows 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 h. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  10. 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.

  11. Influence of Sodium Alginate on Hypoglycemic Activity of Metformin Hydrochloride in the Microspheres Obtained by the Spray Drying

    OpenAIRE

    Szekalska, Marta; Wróblewska, Magdalena; Sosnowska, Katarzyna; Winnicka, Katarzyna

    2016-01-01

    Alginate microspheres with metformin hydrochloride were prepared by the spray drying method in order to improve residence time of drug in the stomach. Nine formulations (F1–F9) with various drug : polymer ratio (1 : 2, 1 : 1, and 2 : 1) and different sodium alginate concentration (1%, 2%, and 3%) were evaluated for size, morphology, drug loading, Zeta potential, and swelling degree. In vitro drug release, mathematical release profile, and physical state of microspheres were also evaluated. Op...

  12. Synthesis of microspheres of triuranium octaoxide by simultaneous water and nitrate extraction from ascorbate-uranyl sols

    International Nuclear Information System (INIS)

    Brykala, M.; Deptula, A.; Rogowski, M.; Lada, W.; Olczak, T.; Wawszczak, D.; Smolinski, T.; Wojtowicz, P.; Modolo, G.

    2014-01-01

    A new method for synthesis of uranium oxide microspheres (diameter <100 μm) has been developed. It is a variant of our patented Complex Sol-Gel Process, which has been used to synthesize high-quality powders of a wide variety of complex oxides. Starting uranyl-nitrate-ascorbate sols were prepared by addition of ascorbic acid to uranyl nitrate hexahydrate solution and alkalizing by aqueous ammonium hydroxide and then emulsified in 2-ethylhexanol-1 containing 1v/o SPAN-80. Drops of emulsion were firstly gelled by extraction of water by the solvent. Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem. Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide. (author)

  13. Functionalized antibiofilm thin coatings based on PLA–PVA microspheres loaded with usnic acid natural compounds fabricated by MAPLE

    Energy Technology Data Exchange (ETDEWEB)

    Grumezescu, Valentina [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele, Bucharest (Romania); University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Department of Science and Engineering of Oxidic Materials and Nanomaterials, Polizu Street no 1-7, 011061 Bucharest (Romania); Socol, Gabriel [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele, Bucharest (Romania); Grumezescu, Alexandru Mihai, E-mail: grumezescu@yahoo.com [University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Department of Science and Engineering of Oxidic Materials and Nanomaterials, Polizu Street no 1-7, 011061 Bucharest (Romania); Holban, Alina Maria [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalelor 1-3, Sector 5, 77206 Bucharest (Romania); Ficai, Anton [University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Department of Science and Engineering of Oxidic Materials and Nanomaterials, Polizu Street no 1-7, 011061 Bucharest (Romania); Truşcǎ, Roxana [S.C. Metav-CD S.A., 31Rosetti Str., 020015 Bucharest (Romania); Bleotu, Coralia [Stefan S Nicolau Institute of Virology, Bucharest (Romania); Balaure, Paul Cǎtǎlin [Department of Organic Chemistry, Faculty of Applied Chemistry and Materials Science, Politehnica Universitiy of Bucharest, Polizu Street no 1-7, 011061 Bucharest (Romania); Cristescu, Rodica [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele, Bucharest (Romania); Chifiriuc, Mariana Carmen [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalelor 1-3, Sector 5, 77206 Bucharest (Romania)

    2014-05-01

    We report the fabrication of thin coatings of PLA–PVA microspheres loaded with usnic acid by matrix assisted pulsed laser evaporation (MAPLE) onto Ti substrate. The obtained coatings have been physico-chemically characterized by scanning electron microscopy (SEM) and infrared microscopy (IRM). In vitro biological assays have been performed in order to evaluate the influence of fabricated microsphere thin coatings on the Staphylococcus aureus biofilm development as well as their biocompatibility. SEM micrographs have revealed a uniform morphology of thin coatings, while IRM investigations have proved both the homogeneity and functional groups integrity of prepared thin coatings. The obtained microsphere-based thin coatings have proved to be efficient vehicles for usnic acid natural compound with antibiofilm activity, as demonstrated by the inhibitory activity on S. aureus mature biofilm development, opening new perspectives for the prevention and therapy associated to biofilm related infections.

  14. Facile dicyandiamide-mediated fabrication of well-defined CuO hollow microspheres and their catalytic application

    International Nuclear Information System (INIS)

    Yang Shengyang; Wang Caifeng; Chen Li; Chen Su

    2010-01-01

    Nearly monodisperse CuO hollow microspheres were successfully synthesized by a straightforward one-pot hydrothermal approach using dicyandiamide (DDA) as structure-guiding agent. The composition, structure and morphology of the products were investigated in detail, via a set of characterizations including X-ray diffraction (XRD) pattern, energy dispersive X-ray (EDX), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results demonstrated that different copper sources and experimental procedures would significantly affect the shape or size of CuO products. A possible formation mechanism of CuO microspheres in this process was thoroughly discussed. Also, some other novel CuO microstructures were fabricated based on DDA-mediated synthetic route. DSC/TGA analysis revealed that as-prepared CuO microspheres can be explored as a promising additive to accelerate the thermal decomposition of ammonium perchlorate, a key oxidizer in composite solid propellants.

  15. Microspheres of UO2, ThO2 and PuO2 for the high temperature reactor

    International Nuclear Information System (INIS)

    Brandau, E.

    2002-01-01

    The production of high temperature reactor fuel, so called pebble fuel, was done in the eighties by a special vibrational dropping process to obtain as sintered UO 2 - or ThO 2 -microspheres, so called 'Kernels', with a diameter size of about 300 μm. These microspheres have been coated and embedded in carbon balls to get the pebble fuel. Since the early nineties BRACE is developing the processings of microspheres starting with sols and suspensions to produce Al 2 O 3 , ZrO 2 , HfO 2 and Actinide oxide microspheres. Two main developments have been made: 1) the preparation of the feed solution (sol, suspension) and the solidification processing, and 2) the equipment, design, and electronic control have been completely changed. A newly developed suspension process for actinide oxides and for metal oxides e.g. Al 2 O 3 , TiO 2 , SiO 2 , ZrO 2 , HfO 2 , CeO 2 , ThO 2 , UO 2 , PuO 2 leads to cheaper production of as sintered microspheres. The processing and the installations will be described and the experience of production will be shown. (author)

  16. Synthesis of Poly(Ortho-Phenylenediamine Fluffy Microspheres and Application for the Removal of Cr(VI

    Directory of Open Access Journals (Sweden)

    Zhoufeng Wang

    2012-01-01

    Full Text Available We reported the synthesis of fluffy poly(o-phenylenediamine (PoPD microspheres via chemical polymerization of oPD monomers by ammonium persulfate (APS at room temperature. The SEM images showed that PoPD microspheres with an average diameter of 1.5 μm and their surfaces consist of highly oriented nanofibers. Furthermore, PoPD microspheres were used as adsorbent materials for the removal of Cr(VI from aqueous solutions. The Cr(VI adsorption behavior on the prepared PoPD microspheres was studied at different adsorption contact times, solution pH values, and amount of the adsorbent. Experimental isotherms of Cr(VI ions were successfully fit to the Langmuir isotherm model. The results indicate that the PoPD fluffy microspheres are an effective adsorbent for the removal of Cr(VI ions from aqueous solutions, and they could be useful in treatment of Cr(VI-polluted wastewaters.

  17. Accelerated in vitro release testing method for naltrexone loaded PLGA microspheres.

    Science.gov (United States)

    Andhariya, Janki V; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J; Shen, Jie

    2017-03-30

    The objective of the present study was to develop a discriminatory and reproducible accelerated release testing method for naltrexone loaded parenteral polymeric microspheres. The commercially available naltrexone microsphere product (Vivitrol ® ) was used as the testing formulation in the in vitro release method development, and both sample-and-separate and USP apparatus 4 methods were investigated. Following an in vitro drug stability study, frequent media replacement and addition of anti-oxidant in the release medium were used to prevent degradation of naltrexone during release testing at "real-time" (37°C) and "accelerated" (45°C), respectively. The USP apparatus 4 method was more reproducible than the sample-and-separate method. In addition, the accelerated release profile obtained using USP apparatus 4 had a shortened release duration (within seven days), and good correlation with the "real-time" release profile. Lastly, the discriminatory ability of the developed accelerated release method was assessed using compositionally equivalent naltrexone microspheres with different release characteristics. The developed accelerated USP apparatus 4 release method was able to detect differences in the release characteristics of the prepared naltrexone microspheres. Moreover, a linear correlation was observed between the "real-time" and accelerated release profiles of all the formulations investigated, suggesting that the release mechanism(s) may be similar under both conditions. These results indicate that the developed accelerated USP apparatus 4 method has the potential to be an appropriate fast quality control tool for long-acting naltrexone PLGA microspheres. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Structuring of diamond films using microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Demo, Pavel; Kromka, Alexander

    2014-01-01

    Roč. 54, č. 5 (2014), s. 320-324 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : nanostructuring * diamond thin films * polystyrene microspheres * reactive ion etching * scanning electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. Method and apparatus for producing microspherical particles

    International Nuclear Information System (INIS)

    Egli, W.; Bailey, W.H.; Leary, D.F.; Lansley, R.J.

    1979-01-01

    This invention relates generally to a method and apparatus for producing microspherical particles and more particularly to a method and apparatus which are particularly useful in connection with the sol-gel process for the production of nuclear fuel kernels. (U.K.)

  20. MICROSPHERE SIZE INFLUENCES THE FOREIGN BODY REACTION

    NARCIS (Netherlands)

    Zandstra, J.; Hiemstra, C.; Petersen, A. H.; Zuidema, J.; van Beuge, M. M.; Rodriguez, S.; Lathuile, A. A. R.; Veldhuis, G. J.; Steendam, R.; Bank, R. A.; Popa, E. R.

    2014-01-01

    Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the

  1. 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.

  2. Inhibition by local bupivacaine-releasing microspheres of acute postoperative pain from hairy skin incision.

    Science.gov (United States)

    Ohri, Rachit; Wang, Jeffrey Chi-Fei; Blaskovich, Phillip D; Pham, Lan N; Costa, Daniel S; Nichols, Gary A; Hildebrand, William P; Scarborough, Nelson L; Herman, Clifford J; Strichartz, Gary R

    2013-09-01

    Acute postoperative pain causes physiological deficits and slows recovery. Reduction of such pain by local anesthetics that are delivered for several days postoperatively is a desirable clinical objective, which is approached by a new formulation and applied in animal studies reported here. We subcutaneously injected a new formulation of poly-lactic-co-glycolic acid polymer microspheres, which provides steady drug release for 96+ hours into rats at the dorsal region 2 hours before surgery. A single 1.2-cm-long skin incision was followed by blunt dissection of skin away from the underlying fascia, and closed by 2 sutures, followed by 14 days of testing. Microspheres containing 5, 10, 20, and 40 mg bupivacaine were injected locally 2 hours before surgery; bupivacaine-free microspheres were the vehicle control, and bupivacaine HCl solution (0.5%), the positive control. Mechanical sensitivity was determined by the frequency of local muscle contractions to repeated pokes with nylon monofilaments (von Frey hairs) exerting 4 and 15 g forces, testing, respectively, allodynia and hyperalgesia, and by pinprick. Injection of bupivacaine microspheres (40 mg drug) into intact skin reduced responses to 15 g von Frey hairs for 6 hours and to pinprick for 36 hours. Respective reductions from bupivacaine HCl lasted for 3 and 2 hours. Skin incision and dissection alone caused mechanical allodynia and hyperalgesia for 14 days. Microspheres containing 20 or 40 mg bupivacaine suppressed postoperative hypersensitivity for up to 3 days, reduced integrated allodynia (area under curve of response versus time) over postoperative days 1 to 5 by 51% ± 20% (mean ± SE) and 78% ± 12%, and reduced integrated hyperalgesia by 55% ± 13% and 64% ± 11%, for the respective doses. Five and ten milligrams bupivacaine in microspheres and the 0.5% bupivacaine solution were ineffective in reducing postoperative hypersensitivity, as were 40 mg bupivacaine microspheres injected contralateral to the

  3. Active self-healing encapsulation of vaccine antigens in PLGA microspheres

    Science.gov (United States)

    Desai, Kashappa-Goud H.; Schwendeman, Steven P.

    2013-01-01

    Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to “actively” load the protein in the polymer pores and facilitate polymer self-healing at temperature > hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigen in PLGA was investigated. Active self-healing encapsulation of two vaccine antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvant (aluminum hydroxide (Al(OH)3) or calcium phosphate). Active loading of vaccine antigen in Al(OH)3-PLGA microspheres was found to: a) increase proportionally with an increasing loading of Al(OH)3 (0.88-3 wt%) and addition of porosigen, b) decrease when the inner Al(OH)3/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively > 0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)3 in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt% TT) and encapsulation efficiency (~ 97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer

  4. Enhanced photocatalytic activity of wool-ball-like TiO2 microspheres on carbon fabric and FTO substrates

    Science.gov (United States)

    Zhang, Yu; Gu, Jian; Zhang, Mengqi

    2018-06-01

    The wool-ball-like TiO2 microspheres on carbon fabric (TiO2-CF) and FTO substrates (TiO2-FTO) have been synthesized by a facile hydrothermal method in alkali environment, using commercial TiO2 (P25) as precursors. The XRD results indicate that the as-prepared TiO2 have good crystallinity. And the SEM images show that the wool-ball-like TiO2 microspheres with a diameter of 2-3 μm are composed of TiO2 nanowires, which have a diameter of 50 nm. The photocatalytic behavior of the wool-ball-like TiO2 microspheres, TiO2-CF and TiO2-FTO under ultraviolet light was investigated by a pseudo first-order kinetic model, using methyl orange (MO) as pollutant. The wool-ball-like TiO2 microspheres obtained a degradation rate constant (Kap) of 6.91×10-3 min-1 . The Kap values of TiO2-FTO and TiO2-CF reach 13.97×10-3 min-1 and 11.80×10-3 min-1, which are 2.0 and 1.7 times higher than that of pristine wool-ball-like TiO2 microspheres due to the "sum effect" between TiO2 and substrates. This study offers a facile hydrothermal method to prepare wool-ball-like TiO2 microspheres on CF and FTO substrates, which will improve the recyclability of phtocatalysts and can be extended to other fields.

  5. Controlled drug delivery for glaucoma therapy using montmorillonite/Eudragit microspheres as an ion-exchange carrier

    Directory of Open Access Journals (Sweden)

    Tian SY

    2018-01-01

    Full Text Available Shuangyan Tian,1 Juan Li,1 Qi Tao,2,3 Yawen Zhao,1 Zhufen Lv,4 Fan Yang,1 Haoyun Duan,5 Yanzhong Chen,4 Qingjun Zhou,5 Dongzhi Hou1 1Guangdong Engineering and Technology Research Center of Topical Precise Drug Delivery System, College of Pharmacy, Department of Pharmaceutics, Guangdong Pharmaceutical University, 2CAS Key Laboratory of Mineralogy and Metallogeny, 3Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 4Guangdong Provincial Key Laboratory of Advanced Drug Delivery Systems, Guangdong Pharmaceutical University, Guangzhou, 5State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China Background: Glaucoma is a serious eye disease that can lead to loss of vision. Unfortunately, effective treatments are limited by poor bioavailability of antiglaucoma medicine due to short residence time on the preocular surface. Materials and methods: To solve this, we successfully prepared novel controlled-release ion-exchange microparticles to deliver betaxolol hydrochloride (BH. Montmorillonite/BH complex (Mt-BH was prepared by acidification-intercalation, and this complex was encapsulated in microspheres (Mt-BH encapsulated microspheres [BMEMs] by oil-in-oil emulsion–solvent evaporation method. The BH loaded into ion-exchange Mt was 47.45%±0.54%. After the encapsulation of Mt-BH into Eudragit microspheres, the encapsulation efficiency of BH into Eudragit microspheres was 94.35%±1.01% and BH loaded into Eudragit microspheres was 14.31%±0.47%. Results: Both Fourier transform infrared spectra and X-ray diffraction patterns indicated that BH was successfully intercalated into acid-Mt to form Mt-BH and then Mt-BH was encapsulated into Eudragit microspheres to obtain BMEMs. Interestingly, in vitro release duration of the prepared BMEMs was extended to 12 hours

  6. Radioisotope diagnosis of pneumonia with the help of labelled microspheres of the blood serum albumin of man (experimental study)

    International Nuclear Information System (INIS)

    Khachirov, Dzh.G.; Petriev, V.M.

    1978-01-01

    The level of accumulation of albumin- 131 I microspheres in the lungs of intact animals reaches 90 per cent of the activity of the introduced preparation. In experimental pneumonia the inclusion of the preparation comprises 81.1+-6.23 per cent. The elimination of the labelled preparation from the lungs in experimental pneumonia occurs two times as slow than that in the control. The labelled microspheres of albumin make it possible to visualize the focus of inflammation, its spreading, conduct observations in dynamics. The peculiarities of accumulation and elimination from the lungs of the mentioned preparation make it possible with its help to differentiate pathological conditions of the lungs: inflammatory process, malignant neoformations and experimental embolism of the pulmonary artery

  7. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1994-04-20

    New, high-strength, hollow, glass microspheres filled with pressurized hydrogen exhibit storage densities which make them attractive for bulk hydrogen storage and transport. The hoop stress at failure of our engineered glass microspheres is about 150,000 psi, permitting a three-fold increase in pressure limit and storage capacity above commercial microspheres, which fail at wall stresses of 50,000 psi. For this project, microsphere material and structure will be optimized for storage capacity and charge/discharge kinetics to improve their commercial practicality. Microsphere production scale up will be performed, directed towards large-scale commercial use. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics` indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as hydride beds, cryocarbons and pressurized tube transports. For microspheres made from advanced materials and processes, analysis will also be performed to identify the appropriate applications of the microspheres considering property variables, and different hydrogen infrastructure, end use, production and market scenarios. This report presents some of the recent modelling results for large beds of glass microspheres in hydrogen storage applications. It includes plans for experiments to identify the properties relevant to large-bed hydrogen transport and storage applications, of the best, currently producible, glass microspheres. This work began in March, 1994. Project successes will be manifest in the matching of cur-rent glass microspheres with a useful application in hydrogen bulk transport and storage, and in developing microsphere materials and processes that increase the storage density and reduce the storage energy requirement.

  8. Copper sulfide microspheres wrapped with reduced graphene oxide for high-capacity lithium-ion storage

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yiyong; Li, Kun; Wang, Yunhui; Zeng, Jing; Ji, Panying; Zhao, Jinbao, E-mail: jbzhao@xmu.edu.cn

    2016-11-15

    Highlights: • We prepare the nanocomposites of Cu{sub x}S microspheres wrapped with rGO. • As-prepared Cu{sub x}S/rGO can effectively accommodate large volume changes. • As-prepared Cu{sub x}S/rGO supply a 2D conductive network. • As-prepared Cu{sub x}S/rGO trap the polysulfides generated during the discharge–charge. • The Cu{sub x}S/rGO has high capacity, cycle stability and excellent rate capability. - Abstract: In this study, a facile two-step approach was developed to prepare the nanocomposites (Cu{sub x}S/rGO) of copper sulfide (Cu{sub x}S) microspheres wrapped with reduced graphene oxide (rGO). The morphology and structure of Cu{sub x}S/rGO materials were researched by using SEM, XRD and laser Raman spectroscopy. As-prepared Cu{sub x}S/rGO nanocomposites, as an active anode material in LIBs, showed distinctly improved electrochemical characteristics, superior cycling stability and high rate capability. Due to the synergistic effect between the Cu{sub x}S microspheres and the rGO nanosheets, as-prepared Cu{sub x}S/rGO nanocomposites could effectively alleviate large volume changes, provide a 2D conductive network and trap the diffusion of polysulfides during the discharge–charge processes, therefore, the Cu{sub x}S/rGO nanocomposites showed excellent electrochemical characteristics.

  9. In vitro evaluation of biodegradable microspheres with surface-bound ligands.

    Science.gov (United States)

    Keegan, Mark E; Royce, Sara M; Fahmy, Tarek; Saltzman, W Mark

    2006-02-21

    Protein ligands were conjugated to the surface of biodegradable microspheres. These microsphere-ligand conjugates were then used in two in vitro model systems to evaluate the effect of conjugated ligands on microsphere behavior. Microsphere retention in agarose columns was increased by ligands on the microsphere surface specific for receptors on the agarose matrix. In another experiment, conjugating the lectin Ulex europaeus agglutinin 1 to the microsphere surface increased microsphere adhesion to Caco-2 monolayers compared to control microspheres. This increase in microsphere adhesion was negated by co-administration of l-fucose, indicating that the increase in adhesion is due to specific interaction of the ligand with carbohydrate receptors on the cell surface. These results demonstrate that the ligands conjugated to the microspheres maintain their receptor binding activity and are present on the microsphere surface at a density sufficient to target the microspheres to both monolayers and three-dimensional matrices bearing complementary receptors.

  10. Fluorine- and iron-modified hierarchical anatase microsphere photocatalyst for water cleaning: facile wet chemical synthesis and wavelength-sensitive photocatalytic reactivity.

    Science.gov (United States)

    Liu, Shaohong; Sun, Xudong; Li, Ji-Guang; Li, Xiaodong; Xiu, Zhimeng; Yang, He; Xue, Xiangxin

    2010-03-16

    High photocatalytic efficiency, easy recovery, and no biological toxicity are three key properties related to the practical application of anatase photocatalyst in water cleaning, but seem to be incompatible. Nanoparticles-constructed hierarchical anatase microspheres with high crystallinity and good dispersion prepared in this study via one-step solution processing at 90 degrees C under atmospheric pressure by using ammonium fluotitanate as the titanium source and urea as the precipitant can reconcile these three requirements. The hierarchical microspheres were found to grow via an aggregative mechanism, and contact recrystallization occurred at high additions of the FeCl(3) electrolyte into the reaction system. Simultaneous incorporation of fluorine and iron into the TiO(2) matrix was confirmed by combined analysis of X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Surface structure and morphology changes of the microspheres induced by high-temperature annealing were clearly observed by field-emission scanning electron microscopy, especially for the phase-transformed particles. The original nanoparticles-constructed rough surfaces partially became smooth, resulting in a sharp drop in photocatalytic efficiency. Interestingly, iron loading has detrimental effects on the visible-light photocatalytic activity of both the as-prepared and the postannealed anatase microspheres but greatly enhances the photocatalytic activity of the as-prepared anatase microspheres under UV irradiation. No matter under UV or visible-light irradiation, the fluorine-loaded anatase microspheres and especially the postannealed ones show excellent photocatalytic performance. The underlying mechanism of fluorine and iron loading on the photocatalytic efficacy of the anatase microspheres was discussed in detail. Beyond photocatalytic applications, this kind of material is of great importance to the assembling of

  11. Facile Synthesis of Magnetic Copolymer Microspheres Based on Poly(glycidyl methacrylate-co-N-isopropylacrylamide/Fe3O4 by Suspension Photopolymerization

    Directory of Open Access Journals (Sweden)

    Siti Zulaikha Mazlan

    2014-01-01

    Full Text Available Magnetic copolymer based on poly(glycidyl methacrylate-co-N-isopropylacrylamide microspheres was prepared by 2,2-dimethoxy-2-phenylacetophenone- (DMPP- photo initiated and poly(vinyl alcohol- (PVA- stabilized single step suspension photopolymerization. The effect of chemical interaction, morphology, and thermal properties by adding 0.1% w/v Fe3O4 in the copolymer was investigated. Infrared analysis (FTIR showed that (C=C band disappeared after copolymerization, indicating that the magnetic copolymer microspheres were successfully synthesized and two important bands at 908 cm−1 and 1550 cm−1 appear. These are associated with the epoxy group stretching of GMA and secondary amide (N–H/C–H deformation vibration of NIPAAm in magnetic microspheres. The X-ray diffraction (XRD result proved the incorporation of Fe3O4 nanoparticles with copolymer microspheres as peak of Fe3O4 was observed. Morphology study revealed that magnetic copolymer exhibited uniform spheres and smoother appearance when entrapped with Fe3O4 nanoparticles. The lowest percentage of Fe3O4 nanoparticles leached from the copolymer microspheres was obtained at pH 7. Finally, thermal property of the copolymer microspheres was improved by adding a small amount of Fe3O4 nanoparticles that has been shown from the thermogram.

  12. One-pot fabrication of Co{sub 3}O{sub 4} microspheres via hydrothermal method at low temperature for high capacity supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Chao; Zhang, Jinfeng [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Deng, Yida, E-mail: yida.deng@tju.edu.cn [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhong, Cheng [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Lei [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Hu, Wenbin [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Highlights: • Take full advantage of the easily oxidized feature of cobalt (II) complexes ammonia. • Low temperature method was applied with absence of subsequent calcination process. • The Co{sub 3}O{sub 4} microspheres possess extraordinary electrochemical properties. - Abstract: Co{sub 3}O{sub 4} microspheres were successfully produced with one-step low temperature hydrothermal method and their electrochemical properties have been investigated. By means of utilizing easily oxidized characteristic of cobalt complexes ammonia, the Co{sub 3}O{sub 4} microspheres were synthesized for the first time with an extremely low hydrothermal temperature (100 °C). In the absent case of surfactant, these Co{sub 3}O{sub 4} microspheres with a diameter of ca. 500 nm and smooth surface were prepared with the assistance of nitrate. Influences concerning about temperature and concentration of nitrate on morphology and size distribution were thoroughly discussed. Electrochemical characterization indicated that the Co{sub 3}O{sub 4} microspheres exhibited high specific capacitance of 850, 780, 700, 630 F/g at current densities of 1, 2, 4, 8 A/g, respectively. And after 1000 cycles, the devices with Co{sub 3}O{sub 4} microspheres showed high charge/discharge reversibility with an efficiency of 90.8% at a current density of 2 A/g.

  13. Thiolated Chitosan Masked Polymeric Microspheres with Incorporated Mesocellular Silica Foam (MCF for Intranasal Delivery of Paliperidone

    Directory of Open Access Journals (Sweden)

    Stavroula Nanaki

    2017-11-01

    Full Text Available In this study, mesocellular silica foam (MCF was used to encapsulate paliperidone, an antipsychotic drug used in patients suffering from bipolar disorder. MCF with the drug adsorbed was further encapsulated into poly(lactic acid (PLA and poly(lactide-co-glycolide (PLGA 75/25 w/w microspheres and these have been coated with thiolated chitosan. As found by TEM analysis, thiolated chitosan formed a thin layer on the polymeric microspheres’ surface and was used in order to enhance their mucoadhesiveness. These microspheres aimed at the intranasal delivery of paliperidone. The DSC and XRD studies showed that paliperidone was encapsulated in amorphous form inside the MCF silica and for this reason its dissolution profile was enhanced compared to the neat drug. In coated microspheres, thiolated chitosan reduced the initial burst effect of the paliperidone dissolution profile and in all cases sustained release formulations have been prepared. The release mechanism was also theoretically studied and three kinetic models were proposed and successfully fitted for a dissolution profile of prepared formulations to be found.

  14. Biodistribution And Preclinical Test Of P-32 Glass Microspheres For Cancer Therapy

    International Nuclear Information System (INIS)

    A, Laksmi; C, Djoharly; P, Ratlan; W, Widyastuti; Purwoko; Bagiwati, Sri; Setiyowati, Sri; Abidin; Sri, Aguswarini

    2003-01-01

    The superiority of radiopharmaceutical compare to the other techniques of medical services, especially for diagnosis and therapy of several deadly diseases such as cancer, shows that this technique is more specific and accurate. P-32-Glass microsphere (P-32 GMS) is one of the radiopharmaceuticals developed recently for therapy using internal radiation method for several malignant cancers, such as hepatic cancer. The P-32 GMS was prepared by irradiating P-31 GMS with neutron at a nuclear reactor, then the preparation was injected to the cancerous infected area. To make easy injection, it needs suspension agent that was including PVP, dextrose and saline with a composition of 16% PVP - 50% dextrose - saline as 2 : 3 : 3 (v/v/v). As microsphere size should be maintained at 40-60 μm, the injection needle was selected properly in order to remain the particle size of P-32 GMS unchanged when the friction occurs between microspheres and the inside surfaces of the needle. The injection needle used was needle produced by BD with a typical size of 20 G1 Tw. Biodistribution studies were carried out after 1, 3, 5 and 24 hour of injection. Experimental results for 1, 3 and 24 hour post-injection studies showed that 100% activity of P-32 GMS was accumulated at the injected area. For 5 hour post-injection study, accumulation of P-32 GMS activity was also found at stomach besides the injected area, but it was presumed as working error

  15. Porous Fe2O3 Microspheres as Anode for Lithium-Ion Batteries

    Science.gov (United States)

    Noerochim, L.; Indra, M. A. T.; Purwaningsih, H.; Subhan, A.

    2018-05-01

    In this work, Fe2O3 was successfully synthesized by the hydrothermal process at low temperature. FeCl3.6H2O as precursor and variation of lysine as hydrolyzing agent were used to preparing Fe2O3. SEM images show that the morphology of Fe2O3 is porous microsphere with sizes in the range of (1 to 5) µm in diameter. The as-prepared Fe2O3 with the 2 M of lysine exhibits excellent cycling performance when used as the anode for lithium ion batteries, obtaining reversible discharge capacity of 172.33 mA·h·g‑1 at 0.5 C after 50 cycles. It is attributed to the unique structure of porous microspheres providing a large surface area which maintains good electronic contact between particles during charge-discharge process. This result demonstrates that Fe2O3 porous microsphere has a high potential as anode material for application of lithium-ion battery.

  16. Optically Levitated Microspheres as a Probe for New Interactions

    Science.gov (United States)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  17. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1995-02-28

    New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for engineered glass microspheres is about 150,000 psi, permitting a three-fold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. This analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers. This paper will describe the matching of current glass microspheres with the useful application in commercial hydrogen bulk transport and storage.

  18. Fabrication of dense (Th0.96U0.04)O2 pellets by Sol Gel Microsphere Pelletisation (SGMP) route

    International Nuclear Information System (INIS)

    Kutty, P.S.; Mishra, Sudhir; Ghoshal, Kaushik; Pillai, S.N.; Nandi, C.; Kumar, Arun; Kumar, N.; Pai, Rajesh V.; Dehadraya, J.V.; Mukerjee, S.K.; Aggarwal, S.K.

    2013-02-01

    Mixed thoria-urania microspheres were prepared by internal gelation process using a sol-gel set up in Fuel Chemistry Division, BARC. The calcined mixed oxide microspheres were heat treated under Ar + 8% H 2 gas mixture and air at different temperatures, ranging from 600 to 800 °C, to obtain feed material ideal for direct compaction. The microspheres were characterised with regards to surface area, crush strength, tap density and size. Green pellets were prepared using different compaction pressures and were sintered to obtain high density (Th 0.96 U 0.04 )O 2 pellets. The sintered pellets were characterised for phase purity, O/M ratio and microstructure. The results indicate that (Th 0.96 U 0.04 )O 2 sintered pellets of densities ranging from 92-96% TD with desired microstructure and O/M ratio could be successfully fabricated by Sol Gel Microsphere Pelletisation (SGMP) route from soft mixed oxide microspheres prepared by Internal gelation process. (author)

  19. Controllable growth of MoS{sub 2}/C flower-like microspheres with enhanced electrochemical performance for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Q.Q., E-mail: zjxqq@hdu.edu.cn; Ji, Z.G.

    2016-07-15

    Tailored design/fabrication of hierarchical porous advanced electrodes is of great importance for developing high-performance power sources. Herein, we report a facile solvothermal method for fabrication of hierarchical porous MoS{sub 2}/C flower-like microspheres. Interestingly, the obtained MoS{sub 2}/C microspheres are composed of interconnected secondary thin nanoflakes and an amorphous carbon layer. As an anode material for lithium ion batteries, the resultant MoS{sub 2}/C flower-like microspheres electrode delivers a high specific capacity of 1125.9 mAh g{sup −1} and good cycle capability (916.6 mAh g{sup −1} at 200 mA g{sup −1} up to 400 cycles), as well as enhanced rate performance. The excellent electrochemical performance is attributed to the unique porous composite architecture with fast transportation of ion/electron and good strain accommodation during the lithiation/delithiation reaction. Our research may pave the way for construction of other high-performance metal sulfides electrodes for electrochemical energy storage. - Graphical abstract: We report a facile solvothermal method for fabrication of hierarchical porous MoS{sub 2}/C flower-like microspheres composed of interconnected thin nanoflakes and an amorphous carbon layer. As an anode material for LIBs, MoS{sub 2}/C flower-like microspheres electrode delivers enhanced electrochemical performance. - Highlights: • We prepared MoS{sub 2}/C flower-like microspheres via a facile solvothermal method. • The microsphere consists of interconnected nanoflake and an amorphous carbon layer. • The MoS{sub 2}/C microspheres show high capacity and good rate performance.

  20. Self-templated Synthesis of Nickel Silicate Hydroxide/Reduced Graphene Oxide Composite Hollow Microspheres as Highly Stable Supercapacitor Electrode Material.

    Science.gov (United States)

    Zhang, Yanhua; Zhou, Wenjie; Yu, Hong; Feng, Tong; Pu, Yong; Liu, Hongdong; Xiao, Wei; Tian, Liangliang

    2017-12-01

    Nickel silicate hydroxide/reduced graphene oxide (Ni 3 Si 2 O 5 (OH) 4 /RGO) composite hollow microspheres were one-pot hydrothermally synthesized by employing graphene oxide (GO)-wrapped SiO 2 microspheres as the template and silicon source, which were prepared through sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO 2 substrate microspheres. The composition, morphology, structure, and phase of Ni 3 Si 2 O 5 (OH) 4 /RGO microspheres as well as their electrochemical properties were carefully studied. It was found that Ni 3 Si 2 O 5 (OH) 4 /RGO microspheres featured distinct hierarchical porous morphology with hollow architecture and a large specific surface area as high as 67.6 m 2  g -1 . When utilized as a supercapacitor electrode material, Ni 3 Si 2 O 5 (OH) 4 /RGO hollow microspheres released a maximum specific capacitance of 178.9 F g -1 at the current density of 1 A g -1 , which was much higher than that of the contrastive bare Ni 3 Si 2 O 5 (OH) 4 hollow microspheres and bare RGO material developed in this work, displaying enhanced supercapacitive behavior. Impressively, the Ni 3 Si 2 O 5 (OH) 4 /RGO microsphere electrode exhibited outstanding rate capability and long-term cycling stability and durability with 97.6% retention of the initial capacitance after continuous charging/discharging for up to 5000 cycles at the current density of 6 A g -1 , which is superior or comparable to that of most of other reported nickel-based electrode materials, hence showing promising application potential in the energy storage area.

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

    Science.gov (United States)

    Xue, Ping; Su, Weiguang; Gu, Yaohua; Liu, Haifeng; Wang, Julan

    2015-03-01

    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.

  2. Removal of Strontium Ions by Immobilized Saccharomyces Cerevisiae in Magnetic Chitosan Microspheres

    Directory of Open Access Journals (Sweden)

    Yanan Yin

    2017-02-01

    Full Text Available A novel biosorbent, immobilized Saccharomyces cerevisiae in magnetic chitosan microspheres was prepared, characterized, and used for the removal of Sr2+ from aqueous solution. The structure and morphology of immobilized S. cerevisiae before and after Sr2+adsorption were observed using scanning electron microscopy with energy dispersive X-ray spectroscopy. The experimental results showed that the Langmuir and Freundlich isotherm models could be used to describe the Sr2+ adsorption onto immobilized S. cerevisiae microspheres. The maximal adsorption capacity (qm was calculated to be 81.96 mg/g by the Langmuir model. Immobilized S. cerevisiae was an effective adsorbent for the Sr2+ removal from aqueous solution.

  3. Porous poly (lactic-co-glycolide) microsphere sintered scaffolds for tissue repair applications

    International Nuclear Information System (INIS)

    Wang Yingjun; Shi Xuetao; Ren Li; Wang Chunming; Wang Dongan

    2009-01-01

    In this paper, a new route to preparing porous poly (lactic-co-glycolide) (PLGA) scaffolds for bone tissue repair applications was developed. Novel porous PLGA scaffolds were fabricated via microsphere sintered technique and gas forming technique. Ammonium bicarbonate was used to regulate porosity of these porous scaffolds. Porosity of the scaffolds, and cell attachment, viability and proliferation on the scaffolds were evaluated. The results indicated that PLGA porous scaffolds were with the porosity from around 30% to 95% by regulating ammonium bicarbonate content from 0 to 10%. We also found that PLGA porous microsphere scaffolds benefited cell attachment and viability. Taken together, the achieved porous scaffolds have controlled porosity and also support mesenchymal stem cell proliferation, which could serve as potential scaffolds for bone repair applications.

  4. Removal of strontium ions by immobilized saccharomyces cerevisiae in magnetic chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yanan; Wang, Jian Long; Yang, Xiao Yong; Li, Weihua [Collaborative Innovation Center for Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China)

    2017-02-15

    A novel biosorbent, immobilized Saccharomyces cerevisiae in magnetic chitosan microspheres was prepared, characterized, and used for the removal of Sr{sup 2+} from aqueous solution. The structure and morphology of immobilized S. cerevisiae before and after Sr{sup 2+}adsorption were observed using scanning electron microscopy with energy dispersive X-ray spectroscopy. The experimental results showed that the Langmuir and Freundlich isotherm models could be used to describe the Sr{sup 2+} adsorption onto immobilized S. cerevisiae microspheres. The maximal adsorption capacity (q{sub m}) was calculated to be 81.96 mg/g by the Langmuir model. Immobilized S. cerevisiae was an effective adsorbent for the Sr{sup 2+} removal from aqueous solution.

  5. Beat frequency ultrasonic microsphere contrast agent detection system

    Science.gov (United States)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  6. Morphology-controlled synthesis of SiO{sub 2} hollow microspheres using pollen grain as a biotemplate

    Energy Technology Data Exchange (ETDEWEB)

    Cao Feng; Li Dongxu, E-mail: caofeng.cn@gmail.co, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

    2009-04-15

    Hollow surface-structured silica microspheres, a potential candidate for drug delivery systems, were synthesized using the rape pollen grain as a biotemplate via a facile sol-gel coating followed by a calcination process. Different surface morphologies relating to the controllable release property were also achieved on the as-prepared silica hollow microspheres by changing the ratio of the tetraethyl orthosilicate (TEOS) and water in sols. Differential scanning calorimetry (DSC) and thermogravity (TG), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), as well as Fourier transform infrared spectroscopy (FT-IR) were utilized to characterize the original pollen grain, the silica sols-coated pollen grain and the as-prepared hollow silica microspheres, respectively. Results indicated that the pollen grain would be removed at around 500 deg. C, and the sol coating was kept to form hollow microspheres. Physical adsorption was proved to be the main effect in the sol coating. A speculation on the formation mechanism of different morphologies is also given.

  7. Morphology-controlled synthesis of SiO2 hollow microspheres using pollen grain as a biotemplate

    International Nuclear Information System (INIS)

    Cao Feng; Li Dongxu

    2009-01-01

    Hollow surface-structured silica microspheres, a potential candidate for drug delivery systems, were synthesized using the rape pollen grain as a biotemplate via a facile sol-gel coating followed by a calcination process. Different surface morphologies relating to the controllable release property were also achieved on the as-prepared silica hollow microspheres by changing the ratio of the tetraethyl orthosilicate (TEOS) and water in sols. Differential scanning calorimetry (DSC) and thermogravity (TG), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), as well as Fourier transform infrared spectroscopy (FT-IR) were utilized to characterize the original pollen grain, the silica sols-coated pollen grain and the as-prepared hollow silica microspheres, respectively. Results indicated that the pollen grain would be removed at around 500 deg. C, and the sol coating was kept to form hollow microspheres. Physical adsorption was proved to be the main effect in the sol coating. A speculation on the formation mechanism of different morphologies is also given.

  8. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Tao, Xiaojun [Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha, 410013, Hunan (China); Zhang, Zhihua; Sun, Xiaomin [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Zhang, Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Key Laboratory of Biomedical Materials of Tianjin, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192 (China)

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration. - Highlights: • Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere proposed for cartilage repair was created. • In vivo, scaffold could enhance cartilage regeneration and integration between the repaired and surrounding cartilage. • In vitro, scaffold exhibits excellent characteristics, such as, improved porosity water absorption and good cell affinity.

  9. Intestinal absorption of PLAGA microspheres in the rat.

    Science.gov (United States)

    Damgé, C; Aprahamian, M; Marchais, H; Benoit, J P; Pinget, M

    1996-12-01

    Rhodamine B-labelled poly (DL-lactide-co-glycolide) (PLAGA) microspheres of 2 different sizes, 1-5 microns and 5-10 microns, were administered as a single dose (1.44 x 10(9) and 1.83 x 10(8) particles, respectively) into the ileal lumen of adult rats. The content of rhodamine in the mesenteric vein and ileal lumen was analysed periodically from 10 min to 48 h as well as the distribution of microspheres in the intestinal mucosa and various other tissues. The concentration of rhodamine decreased progressively in the intestinal lumen and was negligible after 24 h. The number of microspheres in the mesenteric vein increased rapidly and reached a maximum after 4 h whatever the size of the particles. It then decreased progressively, but more rapidly with microspheres > 5 microns than with microspheres PLAGA microspheres mainly crossed the intestinal mucosa at the site of Peyer's patches where microspheres of 5 microns were retained in the ileal lumen. A few small microspheres were occasionally observed in the epithelial cells. Only the smallest particles were recovered in the liver, lymph nodes and spleen while basement membranes were always labelled. It is concluded that PLAGA microspheres could be useful for the oral delivery of antigens if their size is between 1 and 5 microns.

  10. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Ristić, D. [Ruđer Bošković Institute, Division of Materials Physics, Laboratory for Molecular Physics, Bijenička c. 54, Zagreb (Croatia); Center of Excellence for Advanced Materials and Sensing Devices, Research unit New Functional Materials, Bijenička c. 54, Zagreb (Croatia); Berneschi, S.; Camerini, M. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Farnesi, D.; Pelli, S. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Trono, C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Chiappini, A.; Chiasera, A.; Ferrari, M. [CSMFO Group, Istituto di Fotonica e Nanotecnologie, IFN-CNR, Via alla Cascata 56/C, 38050 Povo-Trento (Italy); Lukowiak, A. [Institute of Low Temperature and Structure Research, PAS, ul. Okolna 2, Wroclaw 50-950 (Poland); Dumeige, Y.; Féron, P. [Laboratoire d' Optronique, (CNRS-UMR 6082-Foton), ENSSAT, 6 rue de Kérampont, 22300 Lannion (France); Righini, G.C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Soria, S., E-mail: s.soria@ifac.cnr.it [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Conti, G. Nunzi [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy)

    2016-02-15

    We report experimental results regarding the development of Er{sup 3+}-doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er{sup 3+}-doped glass powders, synthesis of Er{sup 3+}-doped monolithic microspheres by drawing Er{sup 3+}-doped glass, and coating of silica microspheres with an Er{sup 3+}-doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er{sup 3+}-doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  11. Low pressure gas filling of laser fusion microspheres

    International Nuclear Information System (INIS)

    Koo, J.C.; Dressler, J.L.; Hendricks, C.D.

    1979-01-01

    In our laser fusion microsphere production, large, thin gel-microspheres are formed before the chemicals are fused into glass. In this transient stage,, the gel-microspheres are found to be highly permeable to argon and many other inert gases. When the gel transforms to glass, the argon gas, for example, is trapped within to form argon filled, fusion target quality, glass microspheres. On the average, the partial pressure of the argon fills attained in this process is around 2 x 10 4 Pa at room temperature

  12. 75 FR 51668 - Optional Mail Preparation Standards for Flat-Size Mailpieces in FSS Zones

    Science.gov (United States)

    2010-08-23

    ... bundles of six or more addressed pieces each, subject to these standards: * * * * * [Revise item b of 13.2... combination. Mailers will then prepare bundles of uniform size from the pieces in the pool. Bundles must be... this option may be applied to the top piece of each bundle, unless otherwise required to be placed on...

  13. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    H for the immobilized CCL were determined. Activity amelioration of the immobilized CCL for the hydrolysis of olive oil was observed, indicating an interfacial activation of the enzyme after immobilization. Moreover, the immobilized CCL showed enhanced thermal stability and good durability in the repeated use after...