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Sample records for hgh dextran microsphere

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

    NARCIS (Netherlands)

    Vlugt-Wensink, K.D.F.

    2007-01-01

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

  2. Development of poly-l-lysine-coated calcium-alginate microspheres encapsulating fluorescein-labeled dextrans

    Science.gov (United States)

    Charron, Luc; Harmer, Andrea; Lilge, Lothar

    2005-09-01

    A technique to produce fluorescent cell phantom standards based on calcium alginate microspheres with encapsulated fluorescein-labeled dextrans is presented. An electrostatic ionotropic gelation method is used to create the microspheres which are then exposed to an encapsulation method using poly-l-lysine to trap the dextrans inside. Both procedures were examined in detail to find the optimal parameters producing cell phantoms meeting our requirements. Size distributions favoring 10-20 microns microspheres were obtained by varying the high voltage and needle size parameters. Typical size distributions of the samples were centered at 150 μm diameter. Neither the molecular weight nor the charge of the dextrans had a significant effect on their retention in the microspheres, though anionic dextrans were chosen to help in future capillary electrophoresis work. Increasing the exposure time of the microspheres to the poly-l-lysine solution decreased the leakage rates of fluorescein-labeled dextrans.

  3. IL-2 loaded dextran microspheres with attractive histocompatibility properties for local IL-2 cancer therapy

    NARCIS (Netherlands)

    Koten, JW; Van Luyn, MJA; Cade, JA; Hennink, WE; Bijleveld, C; Den Otter, W

    2003-01-01

    Biodegradable dextran microspheres (MS) were developed as a slow-release system for interleukin-2 (IL-2) to apply them for local IL-2 therapy of cancer. We describe the tissue reactions induced by these MS without or with IL-2 in rats. Dextran MS stain bright red-purple with the periodic acid Schiff

  4. 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.

  5. Preparation and Characterization of Quaternized Chitosan Coated Alginate Microspheres for Blue Dextran Delivery

    Directory of Open Access Journals (Sweden)

    Kuo-Yu Chen

    2017-06-01

    Full Text Available In this study, 2-[(Acryloyloxyethyl]trimethylammonium chloride was graft polymerized onto chitosan (CS to form quaternary ammonium CS (QAC by using ammonium persulfate as a redox initiator. Alginate (ALG microspheres loaded with a water-soluble macromolecular model drug, blue dextran (BD, were obtained by corporation of coaxial gas-flow method and ionic gelation process. CS and QAC were then coated on the surfaces of ALG microspheres to generate core/shell structured CS/ALG and QAC/ALG microspheres, respectively. The experiment result showed that QAC/ALG microspheres had a smaller particle size due to the stronger electrostatic interactions between QAC and ALG molecules. In vitro drug release studies at pH 7.4 and pH 9.0 exhibited that the release rate of BD was significantly decreased after ALG microspheres coating with CS and QAC. Moreover, ALG microspheres coated with QAC showed a prolonged release profile for BD at pH 9.0. Therefore, QAC/ALG microspheres may be a promising hydrophilic macromolecular drug carrier for a prolonged and sustained delivery.

  6. Human Growth Hormone (HGH): Does It Slow Aging?

    Science.gov (United States)

    Healthy Lifestyle Healthy aging Human growth hormone is described by some as the key to slowing the aging process. Before you sign up, get the ... slowdown has triggered an interest in using synthetic human growth hormone (HGH) as a way to stave ...

  7. Polymeric microspheres

    Science.gov (United States)

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

    2004-04-13

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

  8. Iron Dextran Injection

    Science.gov (United States)

    Iron dextran injection is used to treat iron-deficiency anemia (a lower than normal number of red blood ... be treated with iron supplements taken by mouth. Iron dextran injection is in a class of medications called ...

  9. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho Sq. 2, 162 06 Prague 6 (Czech Republic)]. E-mail: horak@imc.cas.cz; Petrovsky, Eduard [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Kapicka, Ales [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Frederichs, Theodor [University of Bremen, Department of Geosciences, GEO I, Klagenfurter Strasse, 28359 Bremen (Germany)

    2007-04-15

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  10. Efficient fabrication of high-capacity immobilized metal ion affinity chromatographic media: The role of the dextran-grafting process and its manipulation.

    Science.gov (United States)

    Zhao, Lan; Zhang, Jingfei; Huang, Yongdong; Li, Qiang; Zhang, Rongyue; Zhu, Kai; Suo, Jia; Su, Zhiguo; Zhang, Zhigang; Ma, Guanghui

    2016-03-01

    Novel high-capacity Ni(2+) immobilized metal ion affinity chromatographic media were prepared through the dextran-grafting process. Dextran was grafted to an allyl-activated agarose-based matrix followed by functionalization for the immobilized metal ion affinity chromatographic media. With elaborate regulation of the allylation degree, dextran was completely or partly grafted to agarose microspheres, namely, completely dextran-grafted agarose microspheres and partly dextran-grafted ones, respectively. Confocal laser scanning microscope results demonstrated that a good adjustment of dextran-grafting degree was achieved, and dextran was distributed uniformly in whole completely dextran-grafted microspheres, while just distributed around the outside of the partly dextran-grafted ones. Flow hydrodynamic properties were improved greatly after the dextran-grafting process, and the flow velocity increased by about 30% compared with that of a commercial chromatographic medium (Ni Sepharose FF). A significant improvement of protein binding performance was also achieved by the dextran-grafting process, and partly dextran-grafted Ni(2+) chelating medium had a maximum binding capacity for His-tagged lactate dehydrogenase about 2.5 times higher than that of Ni Sepharose FF. The results indicated that this novel chromatographic medium is promising for applications in high-efficiency and large-scale protein purification. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Comparison of gastroretentive microspheres and sustained-release preparations using theophylline pharmacokinetics.

    Science.gov (United States)

    Miyazaki, Yasunori; Yakou, Shigeru; Takayama, Kozo

    2008-06-01

    The objective of this study was to use the pharmacokinetics of theophylline to compare various gastroretentive microspheres. Three types of theophylline microspheres prepared from a hydrophobic dextran derivative were characterized in terms of drug release in-vitro and floating and mucoadhesive properties. Theophylline pharmacokinetic studies were conducted in Beagle dogs, comparing bulk powder, commercial sustained-release granules (Theodur), sustained-release microspheres, floatable microspheres and mucoadhesive microspheres. Theodur and sustained-release microspheres resulted in a lower maximum concentration (Cmax) (P mucoadhesive microspheres indicated an increase in AUC without decreasing the rate of bioavailability. Overall, the gastroretentive microspheres improved the extent of bioavailability of theophylline, which is absorbable from the entire gastrointestinal tract. The mucoadhesive microsphere showed a prolonged serum drug level, indicating a superior sustained-release delivery system for theophylline.

  12. [A dynamic study of HGH, zinc and copper in diabetic girls. Preliminary report].

    Science.gov (United States)

    González Espinosa, C; García Báez, M; Rodríguez, I; González, C; Lopes, S; Duque, R

    1982-11-01

    A dynamic study study on secretion of HGH in diabetic girls under the combined stimulus of L-dopa and L-arginina is performed. Serum levels for Zinc and copper are measured. Results show that as HGH increase, copper levels decrease. Correlation (r = 0.81, p = 0.05) points to an inverse dependence of both parameters. Concomitantly, the values obtained for zinc and copper are correlated (r = 0.82, p = 0.03). During stimulation, all patients showed an increase in glycemia and a significant correlation between both parameters was found (r = 0.76, p = 0.05).

  13. Computer Modeling Assisted Design of Monodisperse PLGA Microspheres with Controlled Porosity Affords Zero Order Release of an Encapsulated Macromolecule for 3 Months

    NARCIS (Netherlands)

    Kazazi-Hyseni, Filis; Landin, Mariana; Lathuile, Audrey; Veldhuis, Gert J.; Rahimian, Sima; Hennink, Wim E.; Kok, Robbert Jan; van Nostrum, Cornelus F.

    2014-01-01

    Purpose The aim of this study was the development of poly(D,L-lactide-co-glycolide) (PLGA) microspheres with controlled porosity, to obtain microspheres that afford continuous release of a macromolecular model compound (blue dextran). Methods PLGA microspheres with a size of around 40 μm and narrow

  14. Ultrasensitive determination of human growth hormone (hGH) with a disposable electrochemical magneto-immunosensor.

    Science.gov (United States)

    Serafín, V; Úbeda, N; Agüí, L; Yáñez-Sedeño, P; Pingarrón, J M

    2012-05-01

    In this paper, an electrochemical magneto-immunosensor for the detection of human growth hormone (hGH) is described for the first time. The immunosensor involves the use of tosyl-activated magnetic microparticles (TsMBs) to covalently immobilize a monoclonal mAbhHG antibody. A sandwich-type immunoassay with a secondary pAbhGH antibody and anti-IgG labelled with alkaline phosphatase (anti-IgG-AP) was employed. TsMBs–mAbhGH–hGH–pAbhGH–anti-IgG-AP conjugates were deposited onto the surface of a screen-printed gold electrode using a small neodymium magnet, and electrochemical detection was performed by square-wave voltammetry upon the addition of 4-aminophenyl phosphate as the AP substrate. All the variables involved in the preparation of immunoconjugates and in the immunoassay protocol were optimized. A calibration curve for hGH was constructed with a linear range between 0.01 and 100 ng/mL (r = 0.998) and a limit of detection of 0.005 ng/mL. This value is nearly three orders of magnitude lower than that obtained using surface plasmon resonance (Treviño et al., Talanta 78:1011-1016, 2009). Furthermore, good repeatability, with RSD = 3% (n = 10) at the 1-ng/mL hGH level, was obtained. Cross-reactivity studies with other hormones demonstrated good selectivity. The magneto-immunosensor was applied to the analysis of human serum spiked with hGH at the 4- and 0.1-ng/mL levels. Mean recoveries of 96 ± 6% and 99 ± 2%, respectively, were obtained.

  15. FITC-tagged macromolecule-based alginate microspheres for urea sensoring

    Science.gov (United States)

    Joshi, Abhijeet; Chaudhari, Rashmi; Srivastava, Rohit

    2014-04-01

    Urea is an important biomarker for identification of kidney diseases. Early urea detection using a specific and sensitive technique can significantly reduce the mortality of patients. The research aims at developing fluorescence-based FITCmediated pH and urea measurement. A system containing FITC-dextran in alginate microspheres was developed using air-driven atomization. pH/Urea biosensor was characterized using optical microscopy, SEM, and CLSM. Urea biosensing studies were performed by exposing different standard solutions of pH and urea standard solutions using fluorescence spectroscopy (λex=488 nm and λem=520 nm). FITC-dextran was entrapped using an encapsulation unit and alginate microspheres were formed. The microspheres were found to be uniform and spherical in nature with sizes (50±10μ). FITC-dextran was found to be uniformly distributed in the alginate microspheres as per the CLSM scans. Urea biosensing studies indicate that a linear correlation was observed with increasing urea concentrations. The said microspheres can be used to detect changes in pH from 4-8 units owing to its linear response in this range. FITC dextran loaded alginate microspheres showed an improved range of detection upto 7 mM in comparison to 1.5 mM when in solution phase in a study with urea concentrations from 0-50 mM. The pH and urea detection was accurate to an extent of interday variation of 5%. FITC-dextran loaded alginate microspheres show a great potential for usage as a pH and urea biosensor for early detection of kidney diseases.

  16. Magnetic poly(glycidyl methacrylate) microspheres containing maghemite prepared by emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Pollert, E. [Institute of Physics AS CR, 162 53 Prague 6, Cukrovarnicka 10 (Czech Republic)]. E-mail: pollert@fzu.cb; Knizek, K. [Institute of Physics AS CR, 162 53 Prague 6, Cukrovarnicka 10 (Czech Republic); Marysko, M. [Institute of Physics AS CR, 162 53 Prague 6, Cukrovarnicka 10 (Czech Republic); Zaveta, K. [Institute of Physics AS CR, 162 53 Prague 6, Cukrovarnicka 10 (Czech Republic); Joint Laboratory of Moessbauer Spectroscopy, Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8 (Czech Republic); Lancok, A. [Institute of Physics AS CR, 162 53 Prague 6, Cukrovarnicka 10 (Czech Republic); Joint Laboratory of Moessbauer Spectroscopy, Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8 (Czech Republic); Bohacek, J. [Institute of Inorganic Chemistry, AS CR, 250 68 Rez (Czech Republic); Horak, D. [Institute of Macromolecular Chemistry, AS CR, 162 06 Prague 6 (Czech Republic); Babic, M. [Institute of Macromolecular Chemistry, AS CR, 162 06 Prague 6 (Czech Republic)

    2006-11-15

    Magnetic poly(glycidyl methacrylate) (PGMA) microspheres were prepared by emulsion polymerization of glycidyl methacrylate (GMA) in the presence of (carboxymethyl)dextran (CM-dextran)-stabilized iron oxide colloid. Scanning electron microscope (SEM) and transmission electron microscope (TEM) microstructural studies revealed a spherical shape of the particles in 72-84 nm size range. Magnetic iron oxide nanoparticles (< 10 nm) were partly inside the PGMA microspheres and partly adhering to the microsphere surface. X-ray phase analysis revealed spinel structure of the iron oxide particles. According to the Moessbauer spectra, iron oxide consisted mainly of the maghemite phase. Temperature evolution of the spectra completed by the magnetization measurements confirmed superparamagnetic behavior at room temperature and the transition to the ordered state at lower temperatures. As expected, saturated magnetization increased with increasing content of the maghemite phase in the magnetic PGMA microspheres.

  17. Growth hormone-like factor produced by the tapeworm, Spirometra mansonoides, displaces human growth hormone (hGH) from its receptors on cultured human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Watts, D.J.; Phares, C.K.

    1986-03-01

    An analogue of hGH isolated from plerocercoids of the tapeworm Spirometra mansonoides displaces (/sup 125/I)hGH from its receptors in rabbit, rat, and hamster liver membranes. Biologically, plerocercoid growth factor (PGF) is more similar to hGH than to other mammalian GH's but has not been shown to bond human cells. Receptors specific for hGH have been described on cultured human lymphocytes (IM-9). In this study, the authors compared the binding of PGF and hGH in IM-9 cells and in rabbit hepatic membranes. IM-9 lymphocytes (12 x 10/sup 6/ cells/tube) were incubated with (/sup 125/I)hGH and increasing concentrations of hGH (ng/ml) or PGF (serial dilutions) for 90 min at 30/sup 0/ C. Specific binding (B/sub 0/ - NSB) was determined for each dose of hGH or PGF and the binding curves were analyzed by logit-log regression. The results show that PGF displaced (/sup 125/I)hGH from human cells in a dose dependent manner (r = 0.98). Based on the IM-9 assay, 1 ml of the PGF had an activity equivalent to 625 ng of the hGH standard (ngE). However, the binding activity of the PGF in the rabbit liver RRA was 1653 ngE/ml, indicating that the binding potency of PGF in IM-9 cells was only 38% of that in the rabbit liver. These results clearly demonstrate that PGF binds hGH receptors in cells of human origin, suggesting that PGF will be effective in humans.

  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. Biodegradable microspheres targeting mucosal immune-regulating cells: new approach for treatment of inflammatory bowel disease.

    Science.gov (United States)

    Nakase, Hiroshi; Okazaki, Kazuichi; Tabata, Yasuhiko; Chiba, Tsutomu

    2003-03-01

    Several studies have indicated that active monocytes, such as macrophages and T cells, play an important role in the pathogenesis of chronic human inflammatory bowel disease (IBD), although the etiology remains unclear. Manipulation of these cells appears essential for the treatment of patients with IBD. Recently, considerable attention has been paid to the use of polymer microspheres for the sustained release of various drugs and the targeting of therapeutic agents to their site of action. It was reported that biodegradable poly-D,L-lactic acid (PDLLA) microspheres can be efficiently taken up by macrophages and M cells. We evaluated the effect of a new drug delivery system targeting microfold cells and macrophages with PDLLA microspheres and gelatin microspheres (GM) on colitis models. In the first experiment, colitis was induced in Balb/c mice by 5% dextran sodium sulfate, and microspheres containing dexamethsone (Decadrone, Dx; Dx microspheres) were orally administered to these mice. Serum levels of Dx did not reach a detectable level after administration of Dx microspheres. The tissue distribution of microspheres containing 125I-Dx in inflamed colon was significantly higher than that in other organs. The histological score, myeloperoxidase activity, and nitric oxide production of mice treated with Dx microspheres were significantly lower than in those treated with Dx alone. Gene expression of proinflammatory cytokines was remarkably downregulated in mice treated with Dx microspheres compared to Dx alone. Next, we investigated the effect of elimination of resident macrophages using microspheres containing dichloromethylene diphosphonate (DMDP) on IL-10 knockout mice. We administered DMDP microspheres to IL-10 KO mice rectally and assessed whether this reagent could reduce the number of local Mac-1-positive cells in the intestine and suppress the development of colitis in IL-10 KO mice. DMDP microspheres reduced the numbers of resident macrophages in the colon of

  20. hGH isoform differential immunoassays applied to blood samples from athletes: decision limits for anti-doping testing.

    Science.gov (United States)

    Hanley, James A; Saarela, Olli; Stephens, David A; Thalabard, Jean-Christophe

    2014-10-01

    To detect hGH doping in sport, the World Anti-Doping Agency (WADA)-accredited laboratories use the ratio of the concentrations of recombinant hGH ('rec') versus other 'natural' pituitary-derived isoforms of hGH ('pit'), measured with two different kits developed specifically to detect the administration of exogenous hGH. The current joint compliance decision limits (DLs) for ratios derived from these kits, designed so that they would both be exceeded in fewer than 1 in 10,000 samples from non-doping athletes, are based on data accrued in anti-doping labs up to March 2010, and later confirmed with data up to February-March 2011. In April 2013, WADA asked the authors to analyze the now much larger set of ratios collected in routine hGH testing of athletes, and to document in the peer-reviewed literature a statistical procedure for establishing DLs, so that it be re-applied as more data become available. We examined the variation in the rec/pit ratios obtained for 21,943 screened blood (serum) samples submitted to the WADA accredited laboratories over the period 2009-2013. To fit the relevant sex- and kit-specific centiles of the logs of the ratios, we classified 'rec/pit' ratios based on low 'rec' and 'pit' values as 'negative' and fitted statistical distributions to the remaining log-ratios. The flexible data-driven quantile regression approach allowed us to deal with the fact that the location, scale and shape of the distribution of the modeled 'rec/pit' ratios varied with the concentrations of the 'rec' and 'pit' values. The between-kit correlation of the ratios was included in the fitting of the DLs, and bootstrap samples were used to quantify the estimation error in these limits. We examined the performance of these limits by applying them to the data obtained from investigator-initiated hGH administration studies, and in athletes in a simulated cycling stage race. The mean and spread of the distribution of the modeled log-ratios depended in different ways on

  1. MALDI-TOF characterization of hGH1 produced by hairy root cultures of Brassica oleracea var. italica grown in an airlift with mesh bioreactor.

    Science.gov (United States)

    López, Edgar García; Ramírez, Emma Gloria Ramos; Gúzman, Octavio Gómez; Calva, Graciano Calva; Ariza-Castolo, Armando; Pérez-Vargas, Josefina; Rodríguez, Herminia Guadalupe Martínez

    2014-01-01

    Expression systems based on plant cells, tissue, and organ cultures have been investigated as an alternative for production of human therapeutic proteins in bioreactors. In this work, hairy root cultures of Brassica oleracea var. italica (broccoli) were established in an airlift with mesh bioreactor to produce isoform 1 of the human growth hormone (hGH1) as a model therapeutic protein. The hGH1 cDNA was cloned into the pCAMBIA1105.1 binary vector to induce hairy roots in hypocotyls of broccoli plantlets via Agrobacterium rhizogenes. Most of the infected plantlets (90%) developed hairy roots when inoculated before the appearance of true leaves, and keeping the emerging roots attached to hypocotyl explants during transfer to solid Schenk and Hildebrandt medium. The incorporation of the cDNA into the hairy root genome was confirmed by PCR amplification from genomic DNA. The expression and structure of the transgenic hGH1 was assessed by ELISA, western blot, and MALDITOF-MS analysis of the purified protein extracted from the biomass of hairy roots cultivated in bioreactor for 24 days. Production of hGH1 was 5.1 ± 0.42 µg/g dry weight (DW) for flask cultures, and 7.8 ± 0.3 µg/g DW for bioreactor, with productivity of 0.68 ± 0.05 and 1.5 ± 0.06 µg/g DW*days, respectively, indicating that the production of hGH1 was not affected by the growth rate, but might be affected by the culture system. These results demonstrate that hairy root cultures of broccoli have potential as an alternative expression system for production of hGH1, and might also be useful for production of other therapeutic proteins. © 2013 American Institute of Chemical Engineers.

  2. Organic aerogel microspheres

    Science.gov (United States)

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

    1999-01-01

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

  3. Doped zinc oxide microspheres

    Science.gov (United States)

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

    1993-01-01

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

  4. Polyvinyl pyridine microspheres

    Science.gov (United States)

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

    1980-01-01

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

  5. A novel oral preparation of human growth hormone (hGH) is absorbed and increases serum IGF-I levels after 7 days administration to GH-deficient adults

    DEFF Research Database (Denmark)

    Laursen, Torben; Mindeholm, Linda; Haemmerle, Sibylle

    2007-01-01

    Growth hormone deficient (GHD) patients are currently effectively treated with daily subcutaneous (sc) injections of hGH in the evening, but alternative routes would be attractive. An oral formulationulation of hGH, using an amino-caprilic acid derivative (5-CNAC, Emisphere's eligen® technology...... to the end of washout. Further studies should determine optimal formulation, dose and impact of meals, but the possibility of oral delivery of peptides opens new therapeutic perspectives....

  6. Implementation of a SPR immunosensor for the simultaneous detection of the 22K and 20K hGH isoforms in human serum samples.

    Science.gov (United States)

    de Juan-Franco, Elena; Rodríguez-Frade, J M; Mellado, M; Lechuga, Laura M

    2013-09-30

    We have implemented a Surface Plasmon Resonance (SPR) immunosensor based on a sandwich assay for the simultaneous detection of the two main hGH isoforms, of 22 kDa (22K) and 20 kDa (20K). An oriented-antibody sensor surface specific for both hormone isoforms was assembled by using the biotin-streptavidin system. The immunosensor functionality was checked for the direct detection of the 22K hGH isoform in buffer, which gave high specificity and reproducibility (intra and inter-assay mean coefficients of variation of 8.23% and 9% respectively). The selective determination of the 22K and 20K hGH isoforms in human serum samples in a single assay was possible by using two specific anti-hGH monoclonal antibodies. The detection limit for both hormone isoforms was 0.9 ng mL(-1) and the mean coefficient of variation was below 7.2%. The excellent reproducibility and sensitivity obtained indicate the high performance of this immunosensor for implementing an anti-doping test. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. In vivo biocompatibility of dextran-based hydrogels

    NARCIS (Netherlands)

    Cadee, JA; van Luyn, MJA; Brouwer, LA; Plantinga, JA; van Wachem, PB; de Groot, CJ; den Otter, W; Hennink, WE

    2000-01-01

    Dextran-based hydrogels were obtained by polymerization of aqueous solutions of methacrylated dextran (dex-MA) or lactate-hydroxyethyl methacrylate-derivatized dextran (dex-lactate-HEMA). Both nondegradable dex-MA and degradable dex-lactate-HEMA disk-shaped hydrogels, varying in initial water

  8. Plerocercoid growth factor (PGF), a human growth hormone (hGH) analogue produced by the tapeworm Spirometra mansonoides, has direct insulin-like action in adipose tissue of normal rats in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Salem, M.A.M.; Phares, C.K.

    1986-03-01

    The metabolic actions of GH can be divided into acute (insulin-like) and chronic (lipolytic/anti-insulin). The insulin-like actions of GH are most readily elicited in GH-deficient animals as GH induces resistance to its own insulin-like action. Like GH, PGF stimulates growth and cross-reacts with anti-hGH antibodies. Independent experiments were conducted comparing the direct actions of PGF to insulin or hGH in vitro. Insulin-like effects were determined by the ability of PGF, insulin or hGH to stimulate (U-/sup 14/C)glucose metabolism in epidydimal fat pads from normal rats and by inhibition of epinephrine-stimulated lipolysis. Direct stimulation of lipolysis was used as anti-insulin activity. To determine if PGF competes for insulin or GH receptors, adipocytes (3 x 10/sup 5/ cells/ml) were incubated with either (/sup 125/I)insulin or (/sup 125/I)hGH +/- PGF, +/- insulin or +/- hGH. PGF stimulated glucose oxidation and /sup 14/C-incorporation into lipids. Insulin, hGH and PGF inhibited lipolysis (33%, 29% and 34%, respectively). Adipose tissue was very sensitive to the lipolytic effect of hGH but PGF was neither lipolytic nor did it confer refractoriness to its insulin-like action. PGF bound to GH but not to insulin receptors. Therefore, PGF had direct insulin-like effects but did not stimulate lipolysis in tissue from normal rats in vitro.

  9. Evaluation of parameters influencing the molecular delivery by biodegradable microsphere-mediated perforation using femtosecond laser.

    Science.gov (United States)

    Mitsuhashi, Tatsuki; Terakawa, Mitsuhiro

    2014-01-01

    The parameters critically influencing the delivery rate on the biodegradable microsphere-mediated femtosecond (fs) laser perforation are investigated in detail with the aim of developing efficient molecular delivery. Cell membrane was perforated by the irradiation of weakly focused fs laser pulses to the spherical polylactic acid microspheres conjugated to the cell membrane. The delivery of fluorescein isothiocyanate-dextran and fluorescent silica particles to A431 cells is investigated in detail. The increase in the number of irradiated laser pulses had resulted in the increase of delivery rate. The delivery rate depends on the size and functionalization of fluorescent silica particles in which silica particles of 100 nm in diameter were able to be delivered into 20% of the irradiated cells, suggesting that the pore sizes are large enough for the delivery of therapeutic agents into cells. These findings contribute to the development of an efficient and safe phototherapy and drug delivery.

  10. Effects of two oral contraceptives on plasma levels of insulin-like growth factor I (IGF-I) and growth hormone (hGH).

    Science.gov (United States)

    Balogh, A; Kauf, E; Vollanth, R; Gräser, G; Klinger, G; Oettel, M

    2000-11-01

    In 18 healthy women, the effect of two oral contraceptives (OCs) on insulin-like growth factor (IGF-I) and its binding protein-3 (IGFBP-3) and growth hormone (hGH) plasma level were studied before and after intake of either of two OC formulations over 21 days, one containing 2 mg dienogest and 0.03 mg ethinylestradiol (group A) and the other 0.125 mg levonorgestrel and 0.03 mg ethinylestradiol (group B). There was a reduction of the mean IGF-I concentration of 30% (p = 0.008) in the women receiving dienogest-containing pills and 12% (p = 0.006) in women taking the levonogestrel-containing preparation. This difference between drug groups was statistically significant (p = 0.002). A correlation between the control values and the basal-treatment difference (r = 0.945; p = 0.000) was observed only in women of group A. Between basal and treatment cycles the mean plasma levels of hGH remained unchanged in both groups tested, but the 23.5-h integrated mean hGH plasma concentrations (AUC(0-23.5h)) were significantly elevated by 36% (p = 0.016) in comparison to basal values before treatment only in women receiving the levonorgestrel-containing pills. Also, in the women who received the dienogest-containing preparation, the changes of integrated mean plasma level were inversely associated with the control values (r = -0.723; p = 0.025). Neither in group A nor in group B was the mean plasma level of IGFB-3 changed. the results of the present analysis indicate that hormonal contraceptives can modulate the GH and IGF-I-axis in the reproductive age. Probably the androgenic progestogen levonorgestrel (0.125 mg/day) opposes the estrogen-induced action. In the women who took the dienogest-containing formulations (anti-androgenic progestogen-group A), the extent of individual changes (hGh and IGF-I) depends on the basal level prior to pill intake. Further studies, especially of long-term intake of OCs, are necessary to confirm these results and to assess the practical relevance for

  11. Dextran degrading activity of oral microbial flora.

    Science.gov (United States)

    Takamori, K; Mizuno, F; Matsuda, Y; Takahashi, N; Horikawa, T

    1976-03-01

    Dextran degrading activity of the human oral microflora was detected by culturing in TYD broth (Tryptose 1.0%, Yeast extract 0.3%, Dextran T-150 (Pharmacia, MW 150,000) 0.15%). All of the plaue and saliva samples collected from 10 subjects showed a dextran degrading activity, both cultured aerobically and anaerobically, while the anaerobic culture was more active than the aerobic. Furthermore, some individual differences were observed in their activity. Crude enzyme(s) was extracted from the supernatant of a mixed culture of plaque sample by adding ammonium-sulfate to 0.6 and 0.8 saturation (called E-1 and E-2, respectively). E-1 contained 2 dextran-degrading enzymes, one being thought to be an endo-enzyme, with the optimal of H being 5.0 and the other an exo-enzyme with the optimal pH being 7.0-7.5. On the other hand, E-2 contained 1 enzyme of the endo-type. Thirteen strains producing dextranase were isolated from the plaque and were identified as Bacteroides oralis-like organisms. Several other organisms were thought to produce dextranase, although we failed to isolate them in this experiment.

  12. Production of Dextran from Sugar Cane Molasses by Leuconostoc mesenteroides

    Directory of Open Access Journals (Sweden)

    M Faramarzi

    2013-07-01

    Full Text Available Abstract Background & aim: Dextran is a polysaccharide consisting of glucose monomers that are widely used in medicine as a blood volume extender. The aim of this study was to produce dextran from cane molasses using Leuconostoc mesenteroides bacteria. Methods: In this experimental study, for bacterial growth and dextran production, sugarcane molasses was added to the culture medium at different concentrations. Dextran sedimentation was obtained by shaking and centrifugation by adding ethanol after 48 hours. Response surface design was used for qualitative identification of the polarization of dextran and statistical analysis methods. Results: After assessing the separation and interactive effects of the parameters on the optimum amount of dextran produced from sugarcane molasses as 50 g, 35 º C and 5/8 = pH , the Dextran produced was more than 82 g/l. The correlation of the computational model for the dextran produced was 99.5%, which indicated excellent agreement with the experimental and computational models of high accuracy. Conclusion: Dextran produced by Leuconostoc mesenteroides bacteria and sugarcane molasses as substrate, is a cheap and affordable compared to current methods of dextran production. In addition to producing a clinical product, the molasses pollution could be dramatically decreased. Key words: Dextran, Molasses, Leuconostoc Mesenteroides

  13. Dextran-encapsulated photoluminescent gold nanoclusters: synthesis and application

    Science.gov (United States)

    Chiu, Wei-Ju; Chen, Wei-Yu; Lai, Hong-Zheng; Wu, Ching-Yi; Chiang, Hsiang-Lin; Chen, Yu-Chie

    2014-07-01

    Dextrans are widely used as additives in food, pharmaceutical, and cosmetics because of their hydrophilicity, biocompatibility, and low toxicity. These features allow the use of dextrans to modify the surface of nanoparticles to improve cell compatibility for biomedical applications. Additionally, dextran molecules covalently bound with fluorescent dyes are frequently used as tracers in animal studies. These facts show that dextrans are useful compounds for biomedicine-related applications and research. Our aim was to explore a facile way to generate dextran-derived nanoparticles with photoluminescent property for the use in fluorescence imaging of bacteria and cancer cells. Dextran-encapsulated gold nanoclusters (AuNCs@dextran) were generated through a one-pot reaction by stirring dextrans and aqueous tetrachloroauric acid overnight. The generated AuNCs exhibit bright and green photoluminescence under the illumination of an ultraviolet lamp ( λ max = 365 nm), and high cell biocompatibility was found as well. Therefore, the generated AuNCs can be used as fluorescence tracers and nanoprobes. We explored the suitability of AuNCs@dextran as labeling agents for bacteria, such as Staphylococcus aureus and Escherichia coli. After the bacteria were labeled by AuNCs@dextran, they became quite visible under a fluorescence microscope. Additionally, we demonstrated that nanocomposites composed of AuNCs@dextran and silica beads can be readily internalized by cancer cells. The nanocomposites can be readily detected in the cells through their photoluminescence, suggesting possible applications in drug delivery and fluorescence imaging.

  14. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Erah

    Purpose: To formulate theophylline microspheres with cellulose acetate using solvent evaporation method and evaluate the effect of various processing factors on their characteristics. Methods: Microspheres containing theophylline were prepared with a hydrophilic, biocompatible polymer - cellulose acetate - by an ...

  15. Effect of polymerization conditions on the network properties of dex-HEMA microspheres and macro-hydrogels.

    Science.gov (United States)

    Chung, J T; Vlugt-Wensink, K D F; Hennink, W E; Zhang, Z

    2005-01-06

    Dextran-hydroxy-ethyl-methacrylate (dex-HEMA) hydrogels in the form of microspheres are an attractive system for the controlled delivery of protein drugs. In this work, the microspheres were prepared by a water-in-water emulsion polymerization process. The polymerization reaction was initiated by potassium peroxodisulfate (KPS) and catalyzed by N,N,N',N'-tetramethylethylenediamine (TEMED). The effect of the initiator concentration, reaction temperature and pH on the mechanical and network properties of the microspheres were investigated. The size and size distribution of the microspheres, equilibrium water content, and methacrylate conversion were also determined. The mechanical properties of single microspheres were measured by a micromanipulation technique and the rheological characteristics of the same material in the form of macroscopic hydrogel slabs were determined by a controlled stress rheometer. The results showed that the Young's moduli of the microspheres and of macroscopic slabs measured by these two methods were in good agreement. Higher KPS initiator concentrations resulted in a more rapid polymerization with a shorter gelation and lag time, and a higher Young's modulus of the gels. An increase in temperature also resulted in a more rapid polymerization with a shorter gelation and lag time. However, the Young's modulus of the gels decreased with an increase in polymerization temperature. The pH had no significant effect on the mechanical properties of the microspheres. This study demonstrates that the network properties of dex-HEMA hydrogels can be tailored by the polymerization conditions, which opens the possibility to modulate the release rate of entrapped compounds.

  16. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

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

  17. Microspheres and their methods of preparation

    Energy Technology Data Exchange (ETDEWEB)

    Bose, Anima B; Yang, Junbing

    2015-03-24

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

  18. Optimization of dextran syntesis and acidic hydrolisis by surface response analysis

    OpenAIRE

    GUIMARÃES, D.P.; COSTA,F.A.A.; Rodrigues,M. I.; MAUGERI, F.

    1999-01-01

    The influence of some variables in the in vitro synthesis of dextran by dextransucrase from Leusconostoc mesenteroides NRRL B512F, as well as in the acidic hydrolysis of the dextran produced, were studied in order to maximize the production of clinical dextran (dextran 70 and dextran 40). The experiments were conducted using a factorial design and surface response analysis.

  19. Optimization of dextran syntesis and acidic hydrolisis by surface response analysis

    Directory of Open Access Journals (Sweden)

    GUIMARÃES D.P.

    1999-01-01

    Full Text Available The influence of some variables in the in vitro synthesis of dextran by dextransucrase from Leusconostoc mesenteroides NRRL B512F, as well as in the acidic hydrolysis of the dextran produced, were studied in order to maximize the production of clinical dextran (dextran 70 and dextran 40. The experiments were conducted using a factorial design and surface response analysis.

  20. 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.

  1. Microspheres and nanoparticles from ultrasound

    Science.gov (United States)

    Suh, Won Hyuk

    Improved preparations of various examples of monodispersed, porous, hollow, and core-shell metal and semiconductor nanoparticles or nanowires have been developed. Now titania microspheres and nanoparticles and silica microspheres can be synthesized using an inexpensive high frequency (1.7 MHz) ultrasonic generator (household humidifier; ultrasonic spray pyrolysis; USP). Morphology and pore size of titania microspheres were controlled by the silica to Ti(IV) ratio and silica particle size. Fine tuning the precursor ratio affords sub-50 nm titania nanoparticles as well. In terms of silica microspheres, morphology was controlled by the silica to organic monomer ratio. In liquids irradiated with high intensity ultrasound (20 kHz; HIUS), acoustic cavitation produces high energy chemistry through intense local heating inside the gas phase of collapsing bubbles in the liquid. HIUS and USP confine the chemical reactions to isolated sub-micron reaction zones, but sonochemistry does so in a heated gas phase within a liquid, while USP uses a hot liquid droplet carried by a gas flow. Thus, USP can be viewed as a method of phase-separated synthesis using submicron-sized droplets as isolated chemical reactors for nanomaterial synthesis. While USP has been used to create both titania and silica spheres separately, there are no prior reports of titania-silica composites. Such nanocomposites of metal oxides have been produced, and by further manipulation, various porous structures with fascinating morphologies were generated. Briefly, a precursor solution was nebulized using a commercially available household ultrasonic humidifier (1.7 MHz ultrasound generator), and the resulting mist was carried in a gas stream of air through a quartz glass tube in a hot furnace. After exiting the hot zone, these microspheres are porous or hollow and in certain cases magnetically responsive. In the case of titania microspheres, they are rapidly taken up into the cytoplasm of mammalian cells and

  2. 21 CFR 520.1182 - Iron dextran suspension.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Iron dextran suspension. 520.1182 Section 520.1182... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1182 Iron dextran suspension. (a) Specifications. Each milliliter (mL) of suspension contains 55.56 milligrams (mg) iron as ferric...

  3. [Heart arrest during dextran infusion despite hapten blockade].

    Science.gov (United States)

    Schöning, B; Sommer, K; Koch, H

    1984-02-01

    In a running clinical prospective study on the incidence of adverse reactions to colloidal polysaccharides (randomised, single blind, n = 300) a bronchospasm followed by cardiac arrest occurred during dextran infusion although the necessary hapten blockage with monovalent dextran-1 had been effected. Resuscitation was successful. Directly after this, surgery was carried out as planned under general anaesthesia. The 69-year-old patient was discharged without noticeable sequelae. For the first time in the literature on dextran the studied sample allows a generalisation: The event occurred with an incidence of about 0.9% (of 116 patients who had received dextran infusion). This incidence corresponds to a confidence interval ranging from 0.02 to 4.96%. If the study would be continued as planned, the upper limit of this interval signals the probability of another case of severe intolerance. The diagnosis "dextran adverse reaction" can be made in this case by clinical symptoms. Since no previous or concomitant medication had been administered as provided in the protocol to confirm the diagnosis as an adverse reaction to dextran by determination of the titer of dextran antibodies prior to infusion is not required and it may be concluded that dextran was the causative agent.

  4. Mechanical oscillations in lasing microspheres

    Science.gov (United States)

    Toncelli, A.; Capuj, N. E.; Garrido, B.; Sledzinska, M.; Sotomayor-Torres, C. M.; Tredicucci, A.; Navarro-Urrios, D.

    2017-08-01

    We investigate the feasibility of activating coherent mechanical oscillations in lasing microspheres by modulating the laser emission at a mechanical eigenfrequency. To this aim, 1.5%Nd3+:Barium-Titanium-Silicate microspheres with diameters around 50 μm were used as high quality factor (Q > 106) whispering gallery mode lasing cavities. We have implemented a pump-and-probe technique in which the pump laser used to excite the Nd3+ ions is focused on a single microsphere with a microscope objective and a probe laser excites a specific optical mode with the evanescent field of a tapered fibre. The studied microspheres show monomode and multi-mode lasing action, which can be modulated in the best case up to 10 MHz. We have optically transduced thermally activated mechanical eigenmodes appearing in the 50-70 MHz range, the frequency of which decreases with increasing the size of the microspheres. In a pump-and-probe configuration, we observed modulation of the probe signal up to the maximum pump modulation frequency of our experimental setup, i.e., 20 MHz. This modulation decreases with frequency and is unrelated to lasing emission, pump scattering, or thermal effects. We associate this effect to free-carrier-dispersion induced by multiphoton pump light absorption. On the other hand, we conclude that, in our current experimental conditions, it was not possible to resonantly excite the mechanical modes. Finally, we discuss on how to overcome these limitations by increasing the modulation frequency of the lasing emission and decreasing the frequency of the mechanical eigenmodes displaying a strong degree of optomechanical coupling.

  5. 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

  6. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA)

    OpenAIRE

    Susann Neiser; Taija S. Koskenkorva; Katrin Schwarz; Maria Wilhelm; Susanna Burckhardt

    2016-01-01

    Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various int...

  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. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal de-.

  10. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Each microsphere of 100–1000 m was in turn composed of spherical hydroxyapatite granules of 2–15 m size which were obtained by spray drying the precipitated HAP. The parameters such as percentage of initial HAP loading, type of stabilizer, concentration of stabilizer, stirring speed and temperature of microsphere ...

  11. Meltable dextran esters as biocompatible and functional coating materials.

    Science.gov (United States)

    Liebert, Tim; Wotschadlo, Jana; Laudeley, Peggy; Heinze, Thomas

    2011-08-08

    The conversion of dextran with in situ synthesized iminium chlorides of long chain carboxylic acids was used to obtain pure and defined melting dextran esters in an efficient one-pot synthesis. The melting point of these esters can be tailored by the degree of substitutions (DS), the molecular weight of the starting polymer, and the chain length of the ester moiety. The dextran esters give homogeneous and completely transparent melts, which form stable films on a broad variety of materials. Even complex geometries, such as implants, can be evenly coated by multiple melting steps. The films do not display any inhomogeneity and have a very low surface roughness. Therefore, no unspecific protein binding is observed. Moreover, the dextran esters are biocompatible as demonstrated for the interaction with three types of cells namely human brain microvascular endothelial cell, primary human fibroblasts, and mouse myoblast cells.

  12. Rhabdomyolysis after intramuscular iron-dextran in malabsorption.

    OpenAIRE

    Foulkes, W.D.; Sewry, C.; Calam, J.; Hodgson, H. J.

    1991-01-01

    The case of a 59 year old white man who had chronic malabsorption and selective IgA deficiency with severe iron deficiency is reported. In addition, he was deficient in vitamin E and selenium, important antioxidants which protect against lipid peroxidation. He was intolerant of oral iron and when treated with iron-dextran developed symptoms suggestive of polymyositis with evidence of rhabdomyolysis. It is suggested that free iron within iron-dextran activated free radicals, initiating lipid p...

  13. Splenic siderosis and parenteral iron dextran in maintenance haemodialysis patients.

    OpenAIRE

    Murray, J. A.; Slater, D N; Parsons, M. A.; Fox, M.; Smith, S.; Platts, M. M.

    1984-01-01

    The histological features of 40 spleens surgically removed from maintenance haemodialysis patients are reported. Twenty-four of the 40 (60%) showed massive iron loading and a significant direct correlation was found between iron loading and the amount of intravenous iron dextran administered. Since parenteral iron dextran appears to be a major factor in causing iron overload in haemodialysis patients its use as a method of iron replacement in these patients would appear inappropriate.

  14. Biofunctionalization of silica microspheres for protein separation

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  15. Radiation cross-linked collagen/dextran dermal scaffolds: effects of dextran on cross-linking and degradation.

    Science.gov (United States)

    Zhang, Yaqing; Zhang, Xiangmei; Xu, Ling; Wei, Shicheng; Zhai, Maolin

    2015-01-01

    Ionizing radiation effectively cross-links collagen into network with enhanced anti-degradability and biocompatibility, while radiation-cross-linked collagen scaffold lacks flexibility, satisfactory surface appearance, and performs poor in cell penetration and ingrowth. To make the radiation-cross-linked collagen scaffold to serve as an ideal artificial dermis, dextran was incorporated into collagen. Scaffolds with the collagen/dextran (Col/Dex) ratios of 10/0, 7/3, and 5/5 were fabricated via (60)Co γ-irradiation cross-linking, followed by lyophilization. The morphology, microstructure, physicochemical, and biological properties were investigated. Compared with pure collagen, scaffolds with dextran demonstrated more porous appearance, enhanced hydrophilicity while the cross-linking density was lower with the consequence of larger pore size, higher water uptake, as well as reduced stiffness. Accelerated degradation was observed when dextran was incorporated in both the in vitro and in vivo assays, which led to earlier integration with cell and host tissue. The effect of dextran on degradation was ascribed to the decreased cross-linking density, looser microstructure, more porous and hydrophilic surface. Considering the better appearance, softness, moderate degradation rate due to controllable cross-linking degree and good biocompatibility as well, radiation-cross-linked collagen/dextran scaffolds are expected to serve as promising artificial dermal substitutes.

  16. Dextran and gelatin based photocrosslinkable tissue adhesive.

    Science.gov (United States)

    Wang, Tao; Nie, Jun; Yang, Dongzhi

    2012-11-06

    A two-component tissue adhesive based on biocompatible and bio-degradable polymers (oxidized urethane dextran (Dex-U-AD) and gelatin) was prepared and photocrosslinked under the ultraviolet (UV) irradiation. The adhesive could adhere to surface of gelatin, which simulated the human tissue steadily. The structures of above Dex-U-AD were characterized by FTIR, (1)H NMR spectroscopy and XRD. The adhesion property of result products was evaluated by lap-shear test. The maximum adhesion strength could reach to 4.16±0.72 MPa which was significantly higher than that of fibrin glue. The photopolymerization process of Dex-U-AD/gelatin was monitored by real time infrared spectroscopy (RTIR). It took less than 5 min to complete the curing process. The cytotoxicity of Dex-U-AD/gelatin also was evaluated which indicated that Dex-U-AD/gelatin gels were nontoxic to L929 cell. The relationship between all the above-mentioned properties and degree of oxidization of Dex-U-AD was assessed. The obtained products have the potential to serve as tissue adhesive in the future. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. The 20kDa and 22kDa forms of human growth hormone (hGH) exhibit different intracellular signalling profiles and properties.

    Science.gov (United States)

    Yao-Xia, Liu; Jing-Yan, Chen; Xia-Lian, Tang; Ping, Chen; Min, Zhang

    2017-07-01

    Human Growth Hormone (hGH) includes two main variants. The first is 22kDa GH (22K-GH), which is predominant in the blood circulation. The second most abundant variant is 20K-GH, which makes up 5-10% of the blood circulation. Both bind and activate the same receptor, called the human growth hormone receptor (GHR). However, the reason why 22K-GH and 20K-GH exhibit similar, but not identical physiological activities remains poorly understood. In this article, the intracellular signalling profiles between these two hormones were examined. Western blot analyses were performed in 3T3-F442A and CHO cells transfected with GHR (CHO-GHR). The results revealed that both 22K-GH and 20K-GH can activate Janus kinase 2 (JAK2) and signal transducers and activators of transcription 1, 3 and 5 (STATs 1/3/5). Both induced tyrosine phosphorylation of JAK2 and STAT/1/3/5 in a time-dependent and dose-dependent manner. However, there were significant differences in the intracellular signalling properties between 22K-GH and 20K-GH. In particular, the kinetics of signalling shown by 22K-GH and 20K-GH is different. In addition, we found that the 20K-GH-induced tyrosine phosphorylation of signalling proteins was weaker than that of 22K-GH. Together, these observations indicate that the levels and kinetics of phosphorylation mediated by the main signalling proteins triggered by 22K-GH or 20K-GH were not exactly the same. This may provide a possible explanation for the different biological activities exhibited by 22K-GH and 20K-GH. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Synthesis of nanostructured bismuth titanate microspheres.

    Science.gov (United States)

    Du, Hongchu; Wohlrab, Sebastian; Kaskel, Stefan

    2006-07-01

    A hydrothermal method was developed for the synthesis of bismuth titanate nanostructured microspheres. The precursor powder was prepared using a diethylene glycol mediated coprecipitation method. The as-synthesized nanostructured microspheres consisting of granular nanoparticles and nano-platelets were obtained through a hydrothermal treatment of the precursor powder in aqueous sodium hydroxide solution. Tailoring of the morphology was achieved by changing the precursor quantity, sodium hydroxide concentration, and reaction time. The formation mechanism of the nanostructured microspheres probably involves aggregation, followed by dissolution and recrystallization. X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the phase purities, morphologies, and composition of the products.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Huixian Wei

    2012-12-01

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

  1. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Neiser, Susann; Koskenkorva, Taija S; Schwarz, Katrin; Wilhelm, Maria; Burckhardt, Susanna

    2016-07-21

    Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3) and an enzyme-linked immunosorbent assay (ELISA) were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000) does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the mechanisms that may

  2. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA

    Directory of Open Access Journals (Sweden)

    Susann Neiser

    2016-07-01

    Full Text Available Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR, the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3 and an enzyme-linked immunosorbent assay (ELISA were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000 does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the

  3. Organic aerogel microspheres and fabrication method therefor

    Science.gov (United States)

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

    1996-01-01

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

  4. Hydrogen transport and storage in engineered microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G. [Lawrence Livermore National Lab., CA (United States); Hendricks, C. [W.J. Schafer Associates, Livermore, CA (United States)

    1996-10-01

    This project is a collaboration between Lawrence Livermore National Laboratory (LLNL) and W.J. Schafer Associates (WJSA). The authors plan to experimentally verify the performance characteristics of engineered glass microspheres that are relevant to the storage and transport of hydrogen for energy applications. They will identify the specific advantages of hydrogen transport by microspheres, analyze the infrastructure implications and requirements, and experimentally measure their performance characteristics in realistic, bulk storage situations.

  5. New Collagen-Dextran-Zinc Oxide Composites for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Georgeta Păunica-Panea

    2016-01-01

    Full Text Available The goal of this paper was the design, development, and characterization of some new composites, based on collagen and dextran as natural polymers and zinc oxide as antimicrobial, to be used in wound healing. Collagen hydrogels with various concentrations of dextran and zinc oxide were investigated in terms of rheological analysis. The spongious composites, obtained by freeze-drying of hydrogels, were evaluated by morphology (SEM, water uptake, and biological (enzymatic biodegradation analysis. All the results were strongly influenced by the nature and concentration of composite components. Based on the performances of the hydrogels, stationary rheometry, porous structure, morphology, and biological behavior, the antimicrobial spongious composite based on collagen and dextran with 50% ZnO were the most promising for future applications in wound dressing and a biomaterial with high potential in skin regeneration.

  6. Preparation and Characterization of Silica Aerogel Microspheres.

    Science.gov (United States)

    Chen, Qifeng; Wang, Hui; Sun, Luyi

    2017-04-20

    Silica aerogel microspheres based on alkali silica sol were synthesized using the emulsion method. The experimental results revealed that the silica aerogel microspheres (4-20 µm in diameter) were mesoporous solids with an average pore diameter ranging from 6 to 35 nm. The tapping densities and specific surface areas of the aerogel microspheres are in the range of 0.112-0.287 g/cm³ and 207.5-660.6 m²/g, respectively. The diameter of the silica aerogel microspheres could be tailored by varying the processing conditions including agitation rate, water/oil ratio, mass ratio of Span 80: Tween 80, and emulsifier concentration. The effects of these parameters on the morphology and textural properties of the synthesized silica aerogel microspheres were systematically investigated. Such silica aerogel microspheres can be used to prepare large-scale silica aerogels at an ambient pressure for applications in separation and high efficiency catalysis, which requires features of high porosity and easy fill and recovery.

  7. A comparison of analytic procedures for measurement of fractional dextran clearances

    NARCIS (Netherlands)

    Hemmelder, MH; de Jong, PE; de Zeeuw, D

    1998-01-01

    Fractional dextran clearances have been extensively used to study glomerular size selectivity. We report on an analysis of different laboratory procedures involved in measuring fractional dextran clearances. The deproteinization of plasma samples by 20% trichloroacetic acid (TCA) revealed a protein

  8. 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.

  9. Preparation and characterization of ketoprofen-loaded microspheres for embolization.

    Science.gov (United States)

    Zhou, Chao; Cui, Daichao; Zhang, Yuan; Yuan, Huiyan; Fan, Tianyuan

    2012-02-01

    To deliver drug locally and relieve the syndrome of pain after uterine artery embolization, N-[tris (hydroxymethyl) methyl] acrylamide-gelatin microspheres were prepared based on inverse suspension polymerization and then separated into a number of subgroups (150-350, 350-560, 560-710, 710-1,000, and 1,000-1,430 μm) by wet-sieving. The microspheres were dried by lyophilization or by washing with anhydrous ethanol. And ketoprofen was loaded by soaking dried blank microspheres into concentrated ketoprofen ethanol solution. The ketoprofen loading level in different subgroups of microspheres was measured and found higher when the microspheres were dried by lyophilization. Equilibrium water content and mean diameters of microspheres decreased after drug loading, especially in subgroups with larger size. The microspheres went through the catheter without any difficulty. Compression and relaxation tests were performed on microspheres before lyophilization, embosphere™, microspheres after lyophilization and ketoprofen loading microspheres. The Young's moduli were 54.74, 64.19, 98.15, and 120.44 kPa, respectively. The release of ketoprofen from microspheres in different subgroups was studied by using the USPII method and T-cell apparatus, respectively. The results indicate that the release rate of ketoprofen depends upon the diameter of microspheres, the type of dissolution apparatus and the flow rate of media in the case that T-cell apparatus was applied. The CH50 test shows that the activation of complement by ketoprofen-loaded microspheres was lower than by blank ones.

  10. More complications in patients with septic shock treated with dextran compared with crystalloids

    DEFF Research Database (Denmark)

    Rasmussen, Anders Mølgaard; Peter Jakobsen, Rasmus; Strøm, Thomas

    2015-01-01

    of patients admitted to our intensive care unit with septic shock and treated with dextran-70 in the period from 1 January 2009 to 31 December 2009. The controls were included from 1 March 2012 to 28 February 2013 when dextran-70 was replaced with crystalloids. RESULTS: There were 91 patients in the dextran...

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

    African Journals Online (AJOL)

    Purpose: To formulate and evaluate sustained release microspheres of nateglinide (NTG) for enhanced patient compliance. Methods: Nateglinide microspheres were prepared with varying proportions of biodegradable polymers (olibanum gum and guar gum) by calcium chloride/sodium alginate ionic gelation method.

  12. Direct electrochemistry of hemoglobin entrapped in dextran film on ...

    Indian Academy of Sciences (India)

    Direct electrochemistry of hemoglobin (Hb) entrapped in the dextran (De) film on the surface of a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) modified carbon paste electrode (CILE) has been investigated. UV-Vis and FT-IR spectroscopy showed that Hb retained its native ...

  13. Direct electrochemistry of hemoglobin entrapped in dextran film on ...

    Indian Academy of Sciences (India)

    Administrator

    app. ) for the electro- catalytic reaction was calculated as 0⋅17 μM. Keywords. Hemoglobin; dextran; direct electrochemistry; ionic liquid; cyclic voltammetry. 1. Introduction ... in recent years for its potential applications in bio- sensors and bioreactors. ..... had showed some advantages such as biocompatible interface and ...

  14. Microbial Dextran-Hydrolyzing Enzymes: Fundamentals and Applications

    Science.gov (United States)

    Khalikova, Elvira; Susi, Petri; Korpela, Timo

    2005-01-01

    Dextran is a chemically and physically complex polymer, breakdown of which is carried out by a variety of endo- and exodextranases. Enzymes in many groups can be classified as dextranases according to function: such enzymes include dextranhydrolases, glucodextranases, exoisomaltohydrolases, exoisomaltotriohydrases, and branched-dextran exo-1,2-α-glucosidases. Cycloisomalto-oligosaccharide glucanotransferase does not formally belong to the dextranases even though its side reaction produces hydrolyzed dextrans. A new classification system for glycosylhydrolases and glycosyltransferases, which is based on amino acid sequence similarities, divides the dextranases into five families. However, this classification is still incomplete since sequence information is missing for many of the enzymes that have been biochemically characterized as dextranases. Dextran-degrading enzymes have been isolated from a wide range of microorganisms. The major characteristics of these enzymes, the methods for analyzing their activities and biological roles, analysis of primary sequence data, and three-dimensional structures of dextranases have been dealt with in this review. Dextranases are promising for future use in various scientific and biotechnological applications. PMID:15944458

  15. Release of macromolecules 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

    Hydrophilic microspheres based on albumin-heparin conjugates have been prepared as a macromolecular delivery system. The soluble albumin-heparin conjugate was synthesized and crosslinked in a water-in-oil emulsion with glutaraldehyde to form microspheres in the same manner as for albumin microsphere

  16. Nano-functionalization of protein microspheres

    Science.gov (United States)

    Yoon, Sungkwon; Nichols, William T.

    2014-08-01

    Protein microspheres are promising building blocks for the assembly of complex functional materials. Here we demonstrate a set of three techniques that add functionality to the surface of protein microspheres. In the first technique, a positive surface charge on the protein spheres is deposited by electrostatic adsorption. Negatively charged silica and gold nanoparticle colloids can then electrostatically bind reversibly to the microsphere surface. In the second technique, nanoparticles are covalently anchored to the protein shell using a simple one-pot process. The strong covalent bond between sulfur groups in cysteine in the protein shell irreversibly binds to the gold nanoparticles. In the third technique, surface morphology of the protein microsphere is tuned through hydrodynamic instability at the water-oil interface. This is accomplished through the degree of solubility of the oil phase in water. Taken together these three techniques form a platform to create nano-functionalized protein microspheres, which can then be used as building blocks for the assembly of more complex macroscopic materials.

  17. Role of granulocytes in the induction of an experimental endocarditis with a dextran-producing Streptococcus sanguis and its dextran-negative mutant.

    Science.gov (United States)

    Meddens, M. J.; Thompson, J.; Leijh, P. C.; van Furth, R.

    1984-01-01

    The role of granulocytes in the induction of endocarditis with a dextran-producing Streptococcus sanguis and a dextran-negative mutant of this strain was studied. The number of colony-forming units of Streptococcus sanguis needed to colonize the vegetations in 50% of the rabbits (ID50) was significantly lower for the parent strain than for the dextran-negative mutant. However, in granulocytopenic rabbits the ID50s of both strains did not differ measurably. Dextran-negative streptococci were more readily cleared from the circulation than dextran-positive, but in this respect no difference was found between control and granulocytopenic rabbits, which indicates that clearance cannot account for the difference in ID50 between the two strains in the control group. At serum concentrations of 5% and lower, in-vitro granulocytes phagocytosed the dextran-negative streptococci more rapidly than the dextran-positive. The intracellular killing of the streptococci was no influenced by dextran production. This study suggests that an impaired phagocytic removal of attached bacteria from the vegetational surface can be a factor promoting the induction of endocarditis by dextran-producing streptococci. PMID:6201185

  18. 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.

  19. Fabrication of semiconductor microspheres with laser ablation in superfluid helium

    Science.gov (United States)

    Minowa, Yosuke; Oguni, Yuya; Ashida, Masaaki

    2017-04-01

    We fabricated semiconductor ZnO microspheres via the pulsed laser ablation in the superfluid helium. The scanning electron microscope observation revealed the high sphericity and smooth surface. We also observed whispering gallery mode resonances, the electromagnetic eigenmode resonances within the microspheres, in the cathodoluminescence spectrum, verifying the high symmetry of the fabricated microspheres. Further, we cross-sectioned the microspheres with using focused ion beam. The scanning electron microscope observation of the cross section uncovers the existence of small holes within the microspheres. The inner structure examination helps us to understand the microscopic mechanism of our fabrication method.

  20. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    -loaded PHBV microspheres was increased by FA loading. After the initial burst release, FA was released from PLGA microspheres much slower compared to PHBV microspheres. A unique phase separation phenomenon of FA in PLGA but not in PHBV polymers was observed, driven by coalescence of liquid microdroplets...... of 1% (w/w) FA phase separated from PLGA polymer and formed distinct spherical FA-rich amorphous microdomains throughout the PLGA microsphere. For FA-loaded PLGA microspheres, encapsulation efficiency and cumulative release increased with initial drug loading. Similarly, cumulative release from FA...

  1. Surface morphology control of polylactide microspheres enclosing irinotecan hydrochloride.

    Science.gov (United States)

    Yoshizawa, Hidekazu; Nishino, Satoru; Shiomori, Koichiro; Natsugoe, Shoji; Aiko, Takashi; Kitamura, Yoshiro

    2005-05-30

    In order to reduce the initial burst from polylactide (PLA) microspheres enclosing an antitumor agent, we prepared the microspheres with a smooth surface by varying solvent evaporation conditions such as operating temperature and pressure. PLA microspheres enclosing irinotecan hydrochloride (CPT) were prepared using the O/O emulsion system for solvent evaporation. The mean diameter and enclosing efficiency were almost constant because they were independent of solvent evaporation conditions. Scanning electron microscopic (SEM) observation verified the smooth surface of the PLA microspheres produced by varying the preparation conditions. In vitro release experiments show that the initial burst of microspheres with a smooth surface was less than that of those with a rough surface.

  2. Quantum Magnetomechanics with Levitating Superconducting Microspheres

    Science.gov (United States)

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

    2012-10-01

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

  3. 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.

  4. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

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

  5. Effect of Molecular Weight and Molar Ratio of Dextran on Self-Assembly of Dextran Stearate Polymeric Micelles as Nanocarriers for Etoposide

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2012-01-01

    Full Text Available Amphiphilic polymer surfactants are composed of hydrophilic and hydrophobic polymers and are widely used in targeted drug delivery. The purpose of this study was the evaluation of the effect of molecular weight and molar ratio of dextran on physicochemical properties of dextran stearate polymeric micelles. Dextran stearate was synthesized by acylation of dextran with stearoyl chloride. Etoposide loaded polymeric micelles were prepared by dialysis method. The resulting micelles were evaluated for particle size, zeta potential, critical micelle concentration (CMC, drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of micelles were studied in CT-26 colorectal carcinoma cell line. Molecular weight and molar ratio of dextran-stearate were impressive on zeta potential, CMC, drug loading capacity, and release efficiency. Unlike polymer molecular weight, molar ratio of stearate had a significant effect on cytotoxicity and particle size of etoposide loaded micelles. Although molecular weight of dextran had no significant effect on cytotoxicity of micelles on CT-26 cells, it had drastic attributes for stability of polymeric micelles. Consequently, both variables of molecular weight of dextran and molar ratio of stearate should be taken into account to have a stable and effective micelle of dextran-stearate.

  6. Influence of dextran molecular weight on capture in and release from decylamine carboxymethylcellulose capsules.

    Science.gov (United States)

    Mathew, E; Speaker, T J

    1998-01-01

    A series of dextran molecular weight markers were encapsulated in decylamine carboxymethylcellulose microcapsules to serve as probes of capsule retentivity. The capsules were prepared by allowing microdrops of aqueous sodium carboxymethylcellulose to fall into aqueous decylamine acetate solution. Salt exchange reaction at the droplet pseudointerface resulted in self-assembling films which essentially instantaneously enclosed the droplets. Concentrations of anionic polymer were varied in the range from 1-3%. Chromophore-bearing dextrans were incorporated into these capsules by blending the dextrans with the carboxymethylcellulose prior to the encapsulation step. Four dextrans of differing (light scattering) molecular weights were used: 2 x 10(6), 6 x 10(5), 7 x 10(4), and 1.9 x 10(4) amu. The mass balance of dextran retained in the capsules, released on washing the capsules or which escaped encapsulation was determined spectrophotometrically. To measure total dextran in a population of washed capsules, the capsules were lysed in a 0.3 M solution of sodium chloride. To monitor dextran release, washed capsules were suspended in water and dextran concentration in the supernatant was measured. Encapsulation efficiency exceeded 80% for high molecular weight dextran but was lower with the smaller dextrans.

  7. The interactions of fibrinogen and dextrans with erythrocytes

    Science.gov (United States)

    Rampling, M.; Sirs, John A.

    1972-01-01

    1. The rate of packing of erythrocytes in whole blood, under a centrifugal field of 200 g, has been studied using an automatic recording centrifuge. 2. Reduction of the supernatant fibrinogen concentration, by repeatedly washing the cells, lowers the rate of packing and reduces the cell flexibility. 3. Resuspending the cells in their own plasma or in isotonic solutions containing fibrinogen restores their flexibility. 4. Rouleaux formation has been shown to have no effect on the rate of packing by comparison of blood diluted with plasma, isotonic NaCl or Ringer—Locke solutions. While the degree of rouleaux formation varied with the diluent used, the rate of packing and packed cell haematocrit were the same, for the same dilution. 5. Both formalin and dextran altered the degree of rouleaux formation and reduced erythrocyte flexibility. Dextran was found to act indirectly on the erythrocyte flexibility by reducing the plasma fibrinogen concentration. PMID:5046146

  8. Intravenous iron dextran for severe refractory restless legs syndrome.

    Science.gov (United States)

    Ondo, William G

    2010-05-01

    Reduced brain iron is strongly associated with restless legs syndrome (RLS). Oral iron supplements are commonly recommended for RLS but are largely ineffective due to poor absorption and poor tolerability at required doses. Intravenous iron dextran has been shown to increase brain iron content. Surprisingly only a few reports have ever presented data on the clinical effect of high dose intravenous iron for RLS. We retrospectively identified 25 subjects (age 53.2+/-11.9, 7 male) that received intravenous iron for RLS refractory to conventional treatments. We infused 1g of high molecular weight iron dextran over five hours. The age of RLS onset was 32.6+/-13.0 years and 15 subjects had a positive family history of RLS. Patients attempted 7.5+/-2.7 medications for RLS prior to iron therapy. Baseline ferritins ranged from 5 to 248 ng/ml (mean 43.5+/-58.0) and 20/25 had ferritins of less than 50. Two subjects did not complete their entire infusion due to anaphylactic type symptoms but are included. Overall, 2 subjects reported complete amelioration of all RLS symptoms, 11 reported marked improvement, 2 moderate improvement, 3 mild improvement, and 6 reported no improvement. For those with improvement, the duration of effect was highly variable (mean 15.8+/-17.7 weeks, range 1-60 weeks). Twelve subjects had multiple infusions. Iron dextran can dramatically improve refractory RLS but results are inconsistent and not predicted by patient demographics. Although burdened by a higher rate of anaphylactic reactions, iron dextran may be superior to other IV iron preparations. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Radiation synthesis of biocompatible hydrogels of dextran methacrylate

    Science.gov (United States)

    Szafulera, Kamila; Wach, Radosław A.; Olejnik, Alicja K.; Rosiak, Janusz M.; Ulański, Piotr

    2018-01-01

    The aim of this work was to synthesize biocompatible dextran-based hydrogels through crosslinking initiated by ionizing radiation. A series of derivatives of dextran has been synthesized by coupling of methacrylated glycidyl to the structure of this polysaccharide, yielding dextran methacrylate (Dex-MA) of the degree of methacrylate substitution (DS) up to 1.13 as characterised by FTIR and NMR spectroscopy. Chemically crosslinked hydrogels were formed by electron-beam irradiation of Dex-MA in aqueous solution in the absence of low-molecular-weight additives such as catalysts, monomers or crosslinking agents. Crosslinking of Dex-MA in aqueous solutions of 20 g/l and above was an efficient process, the gels were formed at doses as low as 0.5 kGy (experiments conducted up to 100 kGy) and were characterised by high content of insoluble fraction (70-100%). Due to high crosslinking density the equilibrium degree of swelling of fabricated gels was controlled principally by the initial concentration of Dex-MA solution subjected to irradiation, and it was in the range of 20 to over 100 g of water absorbed by gram of gel. Cytocompatibility of hydrogels was examined using XTT assay through evaluation of the cell viability being in indirect contact with hydrogels. The results indicated that hydrogels of Dex-MA of the average DS below 1 were not cytotoxic. Altogether, our data demonstrate that irradiation of methacrylated dextran in aqueous solution is an efficient method of fabrication of biocompatible hydrogels, which applications in regeneration medicine are anticipated.

  10. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... Methods: Microspheres containing theophylline were prepared with a hydrophilic, biocompatible polymer - cellulose acetate - by an emulsion solvent evaporation technique using an acetone/liquid paraffin system containing Span 80 as a surfactant. The effect of processing ...

  11. Tretinoin microsphere gel in younger acne patients.

    Science.gov (United States)

    Jorizzo, Joseph; Grossman, Rachel; Nighland, Marge

    2008-08-01

    Facial acne is common in adolescents and can have a significant psychosocial impact. Treatments prescribed should not add stress by causing excessive localized irritation. To determine whether the lowest concentration of tretinoin microsphere gel (TMG) currently available (0.04%) provides an acceptable balance of efficacy and tolerability for adolescents with moderate facial acne. The findings of 2 multicenter, randomized, double-blind, vehicle-controlled trials of TMG 0.04% applied once nightly for 12 weeks in 245 adolescents ages 11 to 16 years with moderate facial acne were combined. Patients were evaluated via changes in acne lesion counts and the occurrence of cutaneous and other adverse effects. Tretinoin microsphere gel 0.04% reduced total, noninflammatory, and inflammatory lesion counts to a significantly greater extent than the vehicle gel at 12 weeks (PTretinoin microsphere gel 0.04% was tolerated well, with over 70% of patients experiencing no cutaneous adverse events (AEs). Tretinoin microsphere gel 0.04% is effective in significantly reducing all types of acne lesions in adolescents with moderate facial acne ages 11 to 16 years, and has a low incidence of cutaneous AEs.

  12. Biodegradable poly (lactic acid) microspheres containing total ...

    Indian Academy of Sciences (India)

    Drug-releasing behaviour from microspheres was affected by the concentration of emulsifier and the stirring rate. The results demonstrated that a medicated system, which can be potentially applied within a drug delivery system, was designed. This system acts in a systematic manner for the treatment of rheumatoid arthritis.

  13. 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

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

    African Journals Online (AJOL)

    The floating microspheres were evaluated for flow properties based on parameters such as angle of repose and compressibility index, as well as for various other physicochemical properties including particle size, incorporation efficiency, in vitro floatability, and in vitro drug release. The shape and surface morphology of the ...

  15. (PLGA) microspheres-encapsulated vaccine preparation against

    African Journals Online (AJOL)

    Study on the immunogencity of poly(D,L-lactide-coglycolide) (PLGA) microspheres-encapsulated vaccine preparation against Stenotrophomonas maltophilia infection ... of the immune group, the other two groups were not coated with S. maltophilia raising vaccination with inactivated Aeromonas group and the control group.

  16. Multiporous Supramolecular Microspheres for Artificial Photosynthesis.

    Science.gov (United States)

    Tao, Kai; Xue, Bin; Frere, Samuel; Slutsky, Inna; Cao, Yi; Wang, Wei; Gazit, Ehud

    2017-05-23

    Artificial photosynthesis shows a promising potential for sustainable supply of nutritional ingredients. While most studies focus on the assembly of the light-sensitive chromophores to 1-D architectures in an artificial photosynthesis system, other supramolecular morphologies, especially bioinspired ones, which may have more efficient light-harvesting properties, have been far less studied. Here, MCpP-FF, a bioinspired building block fabricated by conjugating porphyrin and diphenylalanine, was designed to self-assemble into nanofibers-based multiporous microspheres. The highly organized aromatic moieties result in extensive excitation red-shifts and notable electron transfer, thus leading to a remarkable attenuated fluorescence decay and broad-spectrum light sensitivity of the microspheres. Moreover, the enhanced photoelectron production and transfer capability of the microspheres are demonstrated, making them ideal candidates for sunlight-sensitive antennas in artificial photosynthesis. These properties induce a high turnover frequency of NADH, which can be used to produce bioproducts in biocatalytic reactions. In addition, the direct electron transfer makes external mediators unnecessary, and the insolubility of the microspheres in water allows their easy retrieval for sustainable applications. Our findings demonstrate an alternative to design new platforms for artificial photosynthesis, as well as a new type of bioinspired, supramolecular multiporous materials.

  17. Composition and structure of calcium aluminosilicate microspheres

    Science.gov (United States)

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

    2017-06-01

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

  18. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    Science.gov (United States)

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

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Hybrid dextran-iron oxide thin films deposited by laser techniques for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Predoi, D.; Ciobanu, C.S. [National Institute for Physics of Materials, P.O. Box MG 07, Bucharest, Magurele (Romania); Radu, M.; Costache, M.; Dinischiotu, A. [Molecular Biology Center, University of Bucharest, 91-95 Splaiul Independentei, 76201, Bucharest 5 (Romania); Popescu, C.; Axente, E.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiations Physics, P. O. Box MG 36, 77125 Bucharest (Romania); Gyorgy, E., E-mail: egyorgy@cin2.es [National Institute for Lasers, Plasma and Radiations Physics, P. O. Box MG 36, 77125 Bucharest (Romania); Consejo Superior de Investigaciones Cientificas, Centre d' Investigacions en Nanociencia i Nanotecnologia (CSIC-CIN2), Campus UAB, 08193 Bellaterra (Spain)

    2012-02-01

    Iron oxide nanoparticles were prepared by chemical co-precipitation method. The nanoparticles were mixed with dextran in distilled water. The obtained solutions were frozen in liquid nitrogen and used as targets during matrix assisted pulsed laser evaporation for the growth of hybrid, iron oxide nanoparticles-dextran thin films. Fourier Transform Infrared Spectroscopy and X-ray diffraction investigations revealed that the obtained films preserve the structure and composition of the initial, non-irradiated iron oxide-dextran composite material. The biocompatibility of the iron oxide-dextran thin films was demonstrated by 3-(4.5 dimethylthiazol-2yl)-2.5-diphenyltetrazolium bromide-based colorimetric assay, using human liver hepatocellular carcinoma cells. - Highlights: Black-Right-Pointing-Pointer Hybrid, dextran-iron oxide nanoparticles and thin films. Black-Right-Pointing-Pointer Laser immobilization. Black-Right-Pointing-Pointer Biocompatibility of dextran-iron oxide nanoparticles.

  20. Production of insoluble dextran using cell-bound dextransucrase of Leuconostoc mesenteroides NRRL B-523.

    Science.gov (United States)

    Padmanabhan, Prabhu Arcot; Kim, Dong-Shik

    2002-09-27

    Water-insoluble, cell-free dextran biosynthesis from Leuconostoc mesenteroides NRRL B-523 has been examined. Cell-bound dextransucrase is used to produce cell-free dextran in a sucrose-rich acetate buffer medium. A comparison between the soluble and insoluble dextrans is made for various sucrose concentrations, and 15% sucrose gave the highest amount of cell-free dextran for a given time. L. mesenteroides B-523 produces more insoluble dextran than soluble dextran. The near cell-free synthesis was validated in a batch reactor, by monitoring the cell growth which is a small (10(6)-10(7) CFU/mL) and constant value throughout the synthesis.

  1. Lower molecular weight intravenous iron dextran for restless legs syndrome.

    Science.gov (United States)

    Cho, Yong Won; Allen, Richard P; Earley, Christopher J

    2013-03-01

    Various techniques used to assess brain iron concentrations have demonstrated the presence of low iron stores in patients with restless legs syndrome (RLS). Previous open-label and randomized studies generally support the value of iron treatment for RLS symptoms. Only one of these studies assessed iron therapy response to changes in brain iron status. The current study was designed to assess the effect of iron therapy on RLS symptoms and on CSF measures of brain iron status. Idiopathic RLS patients drawn from the Korean population received four weekly intravenous (IV) doses of 250 mg low-molecular weight iron dextran for a total dose of 1g. One week after the last dose, any subject on RLS medication tapered off the RLS medications. Blood and CSF samples were taken to measure iron parameters at baseline and again, three weeks after the last dose. We have been following their response to the drug for two years after treatment. Twenty-five patients (age 55.2 ± 9.3, 18 female) enrolled in this study without serious adverse reactions. Seventeen of the 25 patients (68%) showed moderate or complete improvement of all RLS symptoms after treatment based on the Korean-translated versions of the International RLS Severity scale (K-IRLS). Changes in the K-IRLS did not correlate significantly with changes in CSF ferritin. The response to IV iron could not be predicted by patients' demographics, or by blood or CSF iron baseline characteristics. RLS symptom improvement started between one and six weeks after treatment and the treatment benefits lasted from one month to 22 months. Fourteen patients, (56%) completely stopped all medications, for a mean duration of 31.3 ± 33.1 weeks. These results are comparable to those from a prior study with high molecular weight dextran. Intravenous low-molecular weight iron dextran produced significant improvement of RLS symptoms in a majority of patients without any significant adverse effects. Serious anaphylaxis occurs with high molecular

  2. Biomedical properties and preparation of iron oxide-dextran nanostructures by MAPLE technique

    OpenAIRE

    Ciobanu Carmen; Iconaru Simona; Gyorgy Eniko; Radu Mihaela; Costache Marieta; Dinischiotu Anca; Le Coustumer Philippe; Lafdi Khalid; Predoi Daniela

    2012-01-01

    Abstract Background In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films. Results Dextran coated iron oxide nanoparticles thin f...

  3. Cellular interactions of lauric acid and dextran-coated magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Pallab [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Giri, Jyotsnendu [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Mumbai 400076 (India); Banerjee, Rinti [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Bellare, Jayesh [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Bahadur, Dhirendra [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Mumbai 400076 (India)]. E-mail: dhirenb@iitb.ac.in

    2007-04-15

    In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.

  4. 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.

  5. Pluronic F127/chitosan blend microspheres for mucoadhesive drug delivery

    Science.gov (United States)

    Gu, W. Z.; Hu, X. F.

    2017-01-01

    Pluronic F127/chitosan blend microspheres were prepared via emulsification and cross-linking process using glutaraldehyde as a cross-linker. Compared with chitosan microspheres fabricated under the same experimental conditions, blend microspheres exhibited better physical stability and higher swelling capacity. Puerarin, a traditional Chinese medicine, was incorporated into microparticlesas the model drug. The in vitro release of puerarin from blend microspheres was reduced because of the improved compatibility of the drug with the matrices. According to the results from in vitro adhesion experiments, mucoadhesive behavior of blend microspheres on a mucosa-like surface was similar to that of chitosan microspheres, despite their good ability of anti-protein absorption in solution.

  6. Novel materials based on microspheres from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Anshits; T.A. Vereshchagina; O.M. Sharonova; N.N. Anshits; E.V. Rabchevskii; O.A. Bayukov; S.V. Podoinitsyn [Institute of Chemistry and Chemical Technology (Russian Federation)

    2003-07-01

    Several morphological types of microspheres, comparable with synthetic ones by the composition and the properties, are generated during high-temperature thermochemical transformations while burning coal at the power plants. The three-step process for separation of ashes formed as a result of burning three different types of coals, including magnetic separation, hydrodynamic separation and granulometric classification, enabled us to obtain a wide range of stabilized products of magnetic microspheres and cenospheres with purity of 96-99% by the magnetic component. The physical and chemical properties as well as the morphology of the products obtained have been studied in detail by the methods of scanning electron microscopy (SEM), X-ray diffraction, Moessbauer and ESR spectroscopies. The general regularities of microsphere generation from a ferrosilicate melt in burning of coals of different types and the areas of application for the microspheres of different morphological types have been analyzed. The report describes the results of work in the following directions: Recovery of close-cut fractions of microspheres of stabilized composition from fly ashes of three power-generating coals of Russia. Morphological features of magnetic microspheres and cenospheres. Composition and physicochemical properties of close-cut fractions of microspheres of stabilized composition. Application areas of glass crystalline microspheres: catalysts of oxidative conversion of methane; microspherical porous glasses and sorbents on the basis of cenospheres; porous matrices for high-toxic waste disposal, in particular, for liquid radioactive waste. 15 refs., 6 figs., 1 tab.

  7. Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate Microspheres

    Directory of Open Access Journals (Sweden)

    Ipsita Roy

    2011-07-01

    Full Text Available Poly(3-hydroxybutyrate, P(3HB, produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB microspheres using a solid-in-oil-water (s/o/w technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 µm to 1.54 µm with specific surface areas varying between 9.60 m2/g and 6.05 m2/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB microspheres developed in this research has shown high potential to be used in various biomedical applications.

  8. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au [Southern Radiology Group, Radiology Department Sutherland Hospital (Australia); Mackie, Simon [Western General Hospital, Department of Urology (United Kingdom); Aslan, Peter [St George Hospital, Department of Urology (Australia); Cade, David [Sirtex Technology Pty Ltd (Australia); Delprado, Warick [Douglass Hanly Moir Pathology (Australia)

    2016-12-15

    BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.

  9. Microsphere Assemblies via Phosphonate Monoester Coordination Chemistry.

    Science.gov (United States)

    Bladek, Kamila J; Reid, Margaret E; Nishihara, Hirotomo; Akhtar, Farid; Gelfand, Benjamin S; Shimizu, George K H

    2018-02-01

    By complexing a bent phosphonate monoester ligand with cobalt(II), coupled with in situ ester hydrolysis, coordination microspheres (CALS=CALgary Sphere) are formed whereas the use of the phosphonic acid directly resulted in a sheet-like structure. Manipulation of the synthetic conditions gave spheres with different sizes, mechanical stabilities, and porosities. Time-dependent studies determined that the sphere formation likely occurred through the formation of a Co 2+ and ligand chain that propagates in three dimensions through different sets of interactions. The relative rates of these assembly processes versus annealing by ester hydrolysis and metal dehydration determine the growth of the microspheres. Hardness testing by nanoindentation is carried out on the spheres and sheets. Notably, no templates or capping agents are employed, the growth of the spheres is intrinsic to the ligand geometry and the coordination chemistry of cobalt(II) and the phosphonate monoester. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Aptamer Based Microsphere Biosensor for Thrombin Detection

    Directory of Open Access Journals (Sweden)

    Xudong Fan

    2006-08-01

    Full Text Available We have developed an optical microsphere resonator biosensor using aptamer asreceptor for the measurement of the important biomolecule thrombin. The sphere surface ismodified with anti-thrombin aptamer, which has excellent binding affinity and selectivityfor thrombin. Binding of the thrombin at the sphere surface is monitored by the spectralposition of the microsphere’s whispering gallery mode resonances. A detection limit on theorder of 1 NIH Unit/mL is demonstrated. Control experiments with non-aptameroligonucleotide and BSA are also carried out to confirm the specific binding betweenaptamer and thrombin. We expect that this demonstration will lead to the development ofhighly sensitive biomarker sensors based on aptamer with lower cost and higher throughputthan current technology.

  11. Microspheres for the Drug Delivery Applications

    Directory of Open Access Journals (Sweden)

    Hafiz Shoaib Sarwar

    2014-12-01

    Full Text Available Conventional dosage forms provide a sharp increase in plasma drug levels that falls below the therapeutic range after short interval of time until the re-administration of drug. There is a need of such dosage forms which provide not only sustained drug delivery but also reduce the plasma drug levels fluctuations. Microspheres used in drug delivery systems due to their ability to sustain the drug release, their biodegradability and compatibility and targeted drug delivery. In this review different types of microspheres their methods for the preparation with different hydrophilic and hydrophobic polymers, drug loading capacities will be discussed. Different characterizations like SEM, FTIR, XRD, DSC, rheological properties and invitro drug release are successfully described.

  12. A gelatin liver phantom of suspended 90Y resin microspheres to simulate the physiologic microsphere biodistribution of a postradioembolization liver.

    Science.gov (United States)

    Kao, Yung Hsiang; Luddington, Oliver S; Culleton, Simone R; Francis, Roslyn J; Boucek, Jan A

    2014-12-01

    For phantom studies involving (90)Y PET/CT, homogeneous solutions of (90)Y, for example, (90)Y citrate, are commonly used. However, the microsphere biodistribution of a postradioembolization liver is never homogeneous; therefore, such phantoms are physiologically unrealistic for simulating clinical scenarios. The aim of this work was to develop a safe and practical phantom capable of simulating the heterogeneous microsphere biodistribution of a postradioembolization liver. Gelatin (5%) was used to suspend (90)Y resin microspheres, poured into plastic containers to simulate a liver with 2 tumors. Microspheres were added while the gelatin was maintained in a liquid state on a hot plate and continuously stirred with magnetic stir bars. The liquid microsphere mixture was then rapidly cooled in an ice bath while being stirred, resulting in a heterogeneous suspension of microspheres. The completed phantom was serially scanned by (90)Y PET/CT over 2 wk. All scans demonstrated a heterogeneous microsphere distribution throughout the liver and tumor inserts. Serendipitously, magnetic stir bars left inside the phantom produced CT artifacts similar to those caused by embolization coils, whereas pockets of air trapped within the gelatin during its preparation mimicked gas within hollow viscus. The microspheres and tumor inserts remained fixed and suspended within the gelatin, with no evidence of breakdown or leakage. A gelatin phantom realistically simulating the physiologic microsphere biodistribution of a postradioembolization liver is feasible to construct in a radiopharmacy. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  13. 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.

  14. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

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

  15. STUDIES AND EVALUATION OF COMPRESSED MICROSPHERES

    Directory of Open Access Journals (Sweden)

    Idris Mohamed El-Mahdi

    2016-05-01

    Full Text Available This work was aimed at the use of dissolution testing and similarity factor to assess the level of damage taken by active drug microspheres during compression in tablet dosage form. To achieve that, combinations of suitable excipients were used to protect drug microspheres during compression. The excipients were used in the form of powders, granules or placebo pellets prepared by extrusion-spheronization technology. The excipients were evaluated alone, in combinations and post-compression into compacts.  Preliminary experiments included density, hardness, friability and disintegration on all of the selected excipients. Based on such experiments it was found that the flowability of combination powders was more acceptable than individual excipients. Two combinations of microcrystalline -starch and microcrystalline cellulose -calcium carbonate granules were selected to be compressed with active ketoprofen pellets. In all the combinations used there was a significant amount of damage to drug pellets.  The kinetics of drug release appears to follow the zero-order rate and the rate remained unchanged even when a significant degree of damage to pellets occur. It was found that a high level of excipients is required in order to prepare microspheres as a rapid disintegrating tablet. Citation DOI: 10.21502/limuj.002.01.2016  LIMUJ is licensed under a Creative Commons Attribution 4.0 International License

  16. Preparation, characterization and dynamical mechanical properties of dextran-coated iron oxide nanoparticles (DIONPs).

    Science.gov (United States)

    Can, Hatice Kaplan; Kavlak, Serap; ParviziKhosroshahi, Shahed; Güner, Ali

    2017-04-20

    Dextran-coated iron oxide nanoparticles (DIONPs) with appropriate surface chemistry exhibit many interesting properties that can be exploited in a variety of biomedical applications such as magnetic resonance imaging (MRI) contrast enhancement, tissue repair, hyperthermia, drug delivery and in cell separation. This paper reports the experimental detail for preparation, characterization and investigation of thermal and dynamical mechanical characteristics of the dextran-coated Fe3O4 magnetic nanoparticles. In our work, DIONPs were prepared in a 1:2 ratio of Fe(II) and Fe(III) salt in the HCl solution with NaOH at given temperature. The obtained dextran-coated iron-oxide nanoparticles structure-property correlation was characterized by spectroscopic methods; attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and XRD. Coating dextran on the iron-oxide proof of important peaks can be seen from the ATR-FTIR. Dramatic crystallinity increment can be observed from the XRD pattern of the iron-oxide dextran nanoparticles. The thermal analysis was examined by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). Dynamical mechanical properties of dextran nanoparticles were analysed by dynamic mechanical analysis (DMA). Thermal stability of the iron oxide dextran nanoparticles is higher than that of the dextran.

  17. Injectable dextran hydrogels fabricated by metal-free click chemistry for cartilage tissue engineering.

    Science.gov (United States)

    Wang, Xiaoyu; Li, Zihan; Shi, Ting; Zhao, Peng; An, Kangkang; Lin, Chao; Liu, Hongwei

    2017-04-01

    Injectable dextran-based hydrogels were prepared for the first time by bioorthogonal click chemistry for cartilage tissue engineering. Click-crosslinked injectable hydrogels based on cyto-compatible dextran (Mw=10kDa) were successfully fabricated under physiological conditions by metal-free alkyne-azide cycloaddition (click) reaction between azadibenzocyclooctyne-modified dextran (Dex-ADIBO) and azide-modified dextran (Dex-N 3 ). Gelation time of these dextran hydrogels could be regulated in the range of approximately 1.1 to 10.2min, depending on the polymer concentrations (5% or 10%) and ADIBO substitution degree (DS, 5 or 10) of Dex-ADIBO. Rheological analysis indicated that the dextran hydrogels were elastic and had storage moduli from 2.1 to 6.0kPa with increasing DS of ADIBO from 5 to 10. The in vitro tests revealed that the dextran hydrogel crosslinked from Dex-ADIBO DS 10 and Dex-N 3 DS 10 at a polymer concentration of 10% could support high viability of individual rabbit chondrocytes and the chondrocyte spheroids encapsulated in the hydrogel over 21days. Individual chondrocytes and chondrocyte spheroids in the hydrogel could produce cartilage matrices such as collagen and glycosaminoglycans. However, the chondrocyte spheroids produced a higher content of matrices than individual chondrocytes. This study indicates that metal-free click chemistry is effective to produce injectable dextran hydrogels for cartilage tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Novel in situ forming, degradable dextran hydrogels by michael addition chemistry: synthesis, rheology, and degradation

    NARCIS (Netherlands)

    Hiemstra, C.; van der Aa, L.J.; Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan

    2007-01-01

    Various vinyl sulfone functionalized dextrans (dex-VS) (Mn,dextran = 14K or 31K) with degrees of substitution (DS) ranging from 2 to 22 were conveniently prepared by a one-pot synthesis procedure at room temperature. This procedure involved reaction of a mercaptoalkanoic acid with an excess amount

  19. Red blood cell rouleaux formation in dextran solution: dependence on polymer conformation.

    Science.gov (United States)

    Barshtein, G; Tamir, I; Yedgar, S

    1998-01-01

    The velocity of rouleaux formation (RF), as previously shown, increases with increasing dextran concentration up to a critical concentration (Ca), beyond which the addition of dextran reduces the RF velocity (RFV). de Gennes' model for polymer solutions suggests that dextrans exist in two conformations: a coil structure at low concentrations, which changes to a network beyond a critical concentration (C*). In the present study we examined the relation between Ca and C* for dextrans of different molecular weight, and found that they coincide. This suggests that the change in dextran behavior, from increasing to decreasing RFV, occurs when their conformation changes from coil to network. In addition, it has been reported that in dilute dextran solutions the intercellular distance (D) between RBC in rouleaux increases with the molecular weight of the dextran. We found that D correlates with Rf, the end-to-end distance of the polymer molecule, and for all dextrans D < or = 1.5 Rf. In accord with de Gennes' Model for polymers between surfaces, this corresponds to intercellular interaction with two overlapping surface-associated polymer layers, which may extend "tails" to interact with the opposing cells.

  20. Synthesis and characterization of dextran-capped silver nanoparticles with enhanced antibacterial activity.

    Science.gov (United States)

    Yang, Guili; Lin, Qiuxia; Wang, Chunren; Li, Junjie; Wang, Jian; Zhou, Jin; Wang, Yan; Wang, Changyong

    2012-05-01

    Dextran-capped silver nanoparticles were synthesized by reducing silver nitrate with NaBH4 in the presence of dextran as capping agent. The characters of silver nanoparticles were investigated using UV-Vis spectrophotometer, nano-grainsize analyzer, X-ray diffraction, and transmission electron microscopy. Results showed that the silver nanoparticles capped with dextran were in uniform shape and narrow size distribution. Moreover, compared with polyvinylpyrrolidone (PVP)-capped silver nanoparticles, the dextran-capped ones possessed better stability. Antibacterial tests of these silver nanoparticles were carried out for Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Results suggested that the dextran-capped silver nanoparticles had high antibacterial activity against both Gram-positive and Gram-negative bacteria. In addition, the cytotoxicity in vitro of the dextran-capped silver nanoparticles was investigated using mouse fibrosarcoma cells (L929). The toxicity was evaluated by the changes of cell morphology and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Results indicated that these silver nanoparticles had slight effect on the survival and proliferation of L-929 cells at their minimal inhibitory concentration (MIC). After modified by dextran, the physiochemical properties of the silver nanoparticles had been improved. We anticipated that these dextran-capped silver nanoparticles could be integrated into systems for biological and pharmaceutical applications.

  1. Enhanced binding by dextran-grafting to Protein A affinity chromatographic media.

    Science.gov (United States)

    Zhao, Lan; Zhu, Kai; Huang, Yongdong; Li, Qiang; Li, Xiunan; Zhang, Rongyue; Su, Zhiguo; Wang, Qibao; Ma, Guanghui

    2017-04-01

    Dextran-grafted Protein A affinity chromatographic medium was prepared by grafting dextran to agarose-based matrix, followed by epoxy-activation and Protein A coupling site-directed to sulfhydryl groups of cysteine molecules. An enhancement of both the binding performance and the stability was achieved for this dextran-grafted Protein A chromatographic medium. Its dynamic binding capacity was 61 mg immunoglobulin G/mL suction-dried gel, increased by 24% compared with that of the non-grafted medium. The binding capacity of dextran-grafted medium decreased about 7% after 40 cleaning-in-place cycles, much lower than that of the non-grafted medium as decreased about 15%. Confocal laser scanning microscopy results showed that immunoglobulin G was bound to both the outside and the inside of dextran-grafted medium faster than that of non-grafted one. Atomic force microscopy showed that this dextran-grafted Protein A medium had much rougher surface with a vertical coordinate range of ±80 nm, while that of non-grafted one was ±10 nm. Grafted dextran provided a more stereo surface morphology and immunoglobulin G molecules were more easily to be bound. This high-performance dextran-grafted Protein A affinity chromatographic medium has promising applications in large-scale antibody purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Ultraviolet A: Visible spectral absorbance of the human cornea after transepithelial soaking with dextran-enriched and dextran-free riboflavin 0.1% ophthalmic solutions.

    Science.gov (United States)

    Lombardo, Marco; Micali, Norberto; Villari, Valentina; Serrao, Sebastiano; Pucci, Giuseppe; Barberi, Riccardo; Lombardo, Giuseppe

    2015-10-01

    To evaluate the stromal concentration of 2 commercially available transepithelial riboflavin 0.1% solutions in human donor corneas with the use of spectrophotometry. University of Calabria, Rende, Italy. Experimental study. The absorbance spectra of 12 corneal tissues were measured in the 330 to 700 nm wavelength range using a purpose-designed spectrophotometry setup before and after transepithelial corneal soaking with a 15% dextran-enriched riboflavin 0.1% solution (n = 6) or a hypotonic dextran-free riboflavin 0.1% solution (n = 6). Both ophthalmic solutions contained ethylenediaminetetraacetic acid and trometamol as enhancers. In addition, 4 deepithelialized corneal tissues underwent stromal soaking with a 20% dextran-enriched riboflavin 0.1% solution and were used as controls. All the riboflavin solutions were applied topically for 30 minutes. The stromal concentration of riboflavin was quantified by analysis of absorbance spectra of the cornea collected before and after application of each solution. The mean stromal riboflavin concentration was 0.012% ± 0.003% (SD), 0.0005% ± 0.0003% (P < .001), and 0.004% ± 0.001% (P < .01) in tissues soaked with 20% dextran-enriched, 15% dextran-enriched, and hypotonic dextran-free solutions, respectively. The difference of stromal riboflavin concentration between the 2 transepithelial solutions was statistically significant (P < .01). Dextran-enriched solutions required complete corneal deepithelialization to permit effective stromal soaking with riboflavin. Nevertheless, riboflavin in hypotonic dextran-free solution with enhancers permeates across stroma through an intact epithelium. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Coagulation competence for predicting perioperative hemorrhage in patients treated with lactated Ringer's vs. Dextran

    DEFF Research Database (Denmark)

    Rasmussen, Kirsten C; Højskov, Michael; Johansson, Per Ingemar

    2015-01-01

    to receive either lactated Ringer's solution or Dextran 70 (Macrodex ®) that affects coagulation competence. RESULTS: By thrombelastography evaluated coagulation competence, Dextran 70 reduced "maximal amplitude" (MA) by 25 % versus a 1 % reduction with the administration of lactated Ringer's solution (P ....001). Blinded evaluation of the blood loss was similar in the two groups of patients - 2339 ml with the use of Dextran 70 and 1822 ml in the lactated Ringer's group (P = 0.27). Yet, the blood loss was related to the reduction in MA (r = -0.427, P = 0.008) and by multiple regression analysis independently...... associated with MA (P = 0.01). Thus, 11 patients in the dextran group (58 %) developed a clinical significant blood loss (>1500 ml) compared to only four patients (22 %) in the lactated Ringer's group (P = 0.04). CONCLUSIONS: With the use of Dextran 70 vs. lactated Ringer's solution during cystectomy...

  4. Terpene and dextran renewable resources for the synthesis of amphiphilic biopolymers.

    Science.gov (United States)

    Alvès, Marie-Hélène; Sfeir, Huda; Tranchant, Jean-François; Gombart, Emilie; Sagorin, Gilles; Caillol, Sylvain; Billon, Laurent; Save, Maud

    2014-01-13

    The present work shows the synthesis of amphiphilic polymers based on the hydrophilic dextran and the hydrophobic terpenes as renewable resources. The first step concerns the synthesis of functional terpene molecules by thiol-ene addition chemistry involving amino or carboxylic acid thiols and dihydromyrcenol terpene. The terpene-modified polysaccharides were subsequently synthesized by coupling the functional terpenes with dextran. A reductive amination step produced terpene end-modified dextran with 94% of functionalization, while the esterification step produced three terpene-grafted dextrans with a number of terpene units per dextran of 1, 5, and 10. The amphiphilic renewable grafted polymers were tested as emulsifiers for the stabilization of liquid miniemulsion of terpene droplets dispersed in an aqueous phase. The average hydrodynamic diameter of the stable droplets was observed at about 330 nm.

  5. [Anaphylaxis after iron dextran administration in a pregnant woman].

    Science.gov (United States)

    Kortenhorst, Madeleine S Q; Harmsze, Ankie M; Hasaart, Tom H M

    2012-01-01

    Iron deficiency is a frequent cause of anaemia in pregnancy and often results in fatigue and malaise. To prevent complications during labour, timely iron suppletion is important. A 30-year-old multiparous female presented at the outpatient clinic in her 38th week of this pregnancy because of fatigue and lightheadedness. She had been prescribed oral iron suppletion a month earlier but had not taken the tablets. Because her haemoglobin level had decreased to 6.3 mmol/l, it was decided to start her on intravenous iron dextran treatment. During administration of the test dose, the patient experienced acute dyspnoea and severe abdominal and back pain. Foetal bradycardia was observed and the patient underwent an emergency caesarean section. She delivered a healthy boy whose arterial pH was 7.05 (base excess: -7.6 mmol/l) and venous pH was 7.18 (base excess: -6.8 mmol/l). This case demonstrates that dextran anaphylaxis can occur, with potentially lethal consequences, even when no known underlying risk factors are present.

  6. The photocrosslinkable tissue adhesive based on copolymeric dextran/HEMA.

    Science.gov (United States)

    Wang, Tao; Mu, Xueyan; Li, Haibo; Wu, Weilong; Nie, Jun; Yang, Dongzhi

    2013-02-15

    We developed a copolymeric bioadhesive system with the potential to be used as a tissue adhesive based on biopolymer dextran. Copolymeric hydrogels comprising a urethane dextran (Dex-U) and 2-hydroxyethyl methacrylate (HEMA) were prepared and crosslinked under the ultraviolet (UV) irradiation. In this study, the photopolymerization process was monitored by real time infrared spectroscopy (RTIR). The adhesion strength was evaluated by lap-shear-test. The surface tension, viscosity of the solutions and the cytotoxicity assays were investigated. Compared to Dex-U system, the addition of HEMA remarkably improved the properties of Dex-H system especially the adhesion strength and the nontoxicity. And materials variation could be tailored to match the need of tissues. The copolymeric tissue adhesives demonstrated promising adhesion strength and nontoxicity. The maximum adhesion strength reached to 4.33±0.47 Mpa which was 86 times higher than that of Tisseel. The obtained products have the potential to serve as tissue adhesive in the future. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Dextran-Polyacrylamide as Matrices for Creation of Anticancer Nanocomposite

    Directory of Open Access Journals (Sweden)

    G. Telegeev

    2017-01-01

    Full Text Available Drug targeting to specific organs and tissues is one of the crucial endeavors of modern pharmacotherapy. Controlled targeting at the site of action and reduced time of exposure of nontargeted tissues increase the efficacy of the treatment and reduce toxicity and side effects, improving compliance and convenience. Nanocarriers based on the branched copolymers dextran-graft-polyacrylamide were synthesized and characterized and were tested on phagocytic cells. It was shown that these nanoparticles are actively captured by phagocytic cells and that they are not cytotoxic. The polymer nanoparticles loaded with cisplatin at different concentrations from 0.1 to 10 μg/mL yielded dose-dependent decrease in viability of chronic myelogenous leukemia and histiocytic lymphoma cells. The lowest percentage of viable cells was observed for lymphoma cells (22%. Taking into account the fact that our nanoparticles will act mainly on malignant phagocytic cells and do not affect healthy cells, they can thus potentially be used for the therapeutic treatment of tumor cells having phagocytic activity. The effect of nanosilver on cell viability was lower than the one of polymer/cisplatin composite. The data from the cytotoxic studies indicate that nanosilver induces toxicity in cells. However, when the copolymers were conjugated to both nanosilver and cisplatin, such a nanosystem displayed less cytotoxic effect compared to the conjugates of dextran-polyacrylamide and cisplatin.

  8. Microsphere transport in a fractured soil during intermittent flow: effect of microsphere sizes and soil physical heterogeneity

    Science.gov (United States)

    Mohanty, S. K.; Bulicek, M.; Metge, D. W.; Harvey, R. W.; Boehm, A. B.; Ryan, J. N.

    2012-12-01

    The aim of this study was to evaluate the effect of soil physical heterogeneity on the transport of microspheres, used as surrogates for bacteria, during simulated intermittent rain. Artificial rainwater containing microspheres of two sizes (0.5 and 1.8 μm diameter) and bromide (1 mM) was applied to an intact soil core. After cessation of simulated rainfall, three more intermittent rainfalls were applied to the core in order to document remobilizing of the previously sequestered microspheres. Each intermittent rainfall consisted of 4 h rain preceded by 20 h pause. Water samples were collected using a 19-port grid at the bottom of the soil core to resolve the effect of core physical heterogeneity on the mobilization of microspheres. Flow was detected at 6 of 19 ports indicating occurrence of preferential flow. Microspheres preferentially migrated through fractures in soil, whereas bromide was retarded due to matrix diffusion. Bromide concentrations in the effluent declined throughout the experiment, but microsphere concentrations peaked after the pauses in rainfall. Additionally, the recovery of microspheres during intermittent flow was greatest in the port with highest flow. Thus, it appears that bromide transport is diffusion-limited, whereas the dominant mechanism for mobilization of microspheres appeared to involve shear from the advancing wetting font. Mobilization of microspheres increased with microsphere sizes presumably due to larger microspheres preferentially transported through fractures or macropores. The results of the study provide evidence that intermittent flow has potential to rapidly mobilize colloids and colloid-associated contaminants including bacteria through fractures or macropores in soil.

  9. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fusion, is a means of producing energy by imploding small hollow microspheres containing thermonuclear fusion fuel. Polymer microspheres, which are used as fuel containers, can be produced by solution-based micro-encapsulation technique ...

  10. Formulation and Evaluation of Microspheres Based on Gelatin ...

    African Journals Online (AJOL)

    µg.h/ml for the control, 262±3.47 µg.h/ml for microspheres based on gelatine only and 328±2.55 µg.h/ml for microspheres formulated with equal parts of gelatin and mucin. Conclusion: The inclusion of S-mucin in the composition of the ...

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

    Science.gov (United States)

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

    2013-09-17

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

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

    African Journals Online (AJOL)

    HP

    associated with indomethacin adverse effects due to drug accumulation [8]. CONCLUSION. The test and reference formulations were bioequivalent based on both the in vitro and in vivo data obtained, Thus, indomethacin microspheres encapsulated in sugar wax microspheres by melt method showed good potential for ...

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

    African Journals Online (AJOL)

    Purpose: To employ response surface methodology (RSM) for statistical optimization of formulation factors in the preparation of celecoxib-loaded microspheres. Methods: Celecoxib microspheres were prepared by solvent evaporation method. Biodegradable/biocompatible polymers, Eudragit L-100 and polyvinyl ...

  14. 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 ...

  15. 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 ...

  16. Surface Wrinkling on Polydimethylsiloxane Microspheres via Wet Surface Chemical Oxidation

    Science.gov (United States)

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

    2014-07-01

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

  17. Tissue reactions of in situ formed dextran hydrogels crosslinked by stereocomplex formation after subcutaneous implantation in rats

    NARCIS (Netherlands)

    Bos, GW; Hennink, WE; Brouwer, LA; den Otter, W; Veldhuis, TFJ; van Nostrum, CF; van Luyn, MJA

    In this study, the in vivo biocompatibility of physically crosslinked dextran hydrogels was investigated. These hydrogels were obtained by mixing aqueous solutions of dextran grafted with L-lactic acid oligomers and dextran grafted with D-lactic acid oligomers. Gelation occurs due to stereocomplex

  18. Biomedical properties and preparation of iron oxide-dextran nanostructures by MAPLE technique.

    Science.gov (United States)

    Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Gyorgy, Eniko; Radu, Mihaela; Costache, Marieta; Dinischiotu, Anca; Le Coustumer, Philippe; Lafdi, Khalid; Predoi, Daniela

    2012-03-13

    In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films. Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p3/2 of two thin films of dextran coated iron oxide is consistent with Fe3+ oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe2O3, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control. The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications.

  19. Computational dynamics of acoustically-driven microsphere systems

    CERN Document Server

    Glosser, Connor A; Dault, Daniel L; Piermarocchi, Carlo; Shanker, Balasubramaniam

    2015-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the inter-particle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of non-dissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities, and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation ...

  20. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Energy Technology Data Exchange (ETDEWEB)

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A.; Brown, Gilbert M.

    2017-04-11

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.

  1. Plasma FITC-dextran exchange between the primary and secondary circulatory systems in the Atlantic cod, Gadus Morhua

    DEFF Research Database (Denmark)

    Fischer, Claes; Steffensen, John Fleng

    2008-01-01

    Fluorescein isothiocyanate dextran (FITC-dextran) exchange between the primary (PCS) and secondary (SCS) circulatory systems in the Atlantic cod, Gadus morhua (Linnaeus, 1752), were studied using 20-kDa (n = 4) and 500-kDa (n = 4) FITC-dextran. In order to give a qualitative perspective...... of the injected 500-kDa FITC-dextran was also examined, and it was observed that of the 500-kDa FITC-dextran lost from the primary and secondary vascular systems, 63.0 +/- 9.2% could be recovered from the liver....

  2. Evaluation of the safety of iron dextran with parenteral nutrition in the paediatric inpatient setting.

    Science.gov (United States)

    Lee, Dale; Barsky, Diane; Hughes, Rachel; Driggers, Julia; Poupard, Nicole; Mascarenhas, Maria

    2017-11-01

    Practitioners often avoid administering iron dextran in parenteral nutrition (PN) for hospitalised children because of the concern for anaphylaxis. The primary aim of the present study was to determine the risk of anaphylaxis associated with exposure to PN containing iron dextran in the inpatient setting. Charts were reviewed for all children admitted to The Children's Hospital of Philadelphia from January 1, 2011 to December 30, 2013 who received PN containing low molecular weight (LMW) iron dextran. Subject characteristics, primary diagnoses and PN orders were evaluated. The pharmacy adverse events database was queried for adverse drug reactions. Over three years, 89 subjects received PN containing a maintenance dose of LMW iron dextran with a total of 2774 days of exposure. Subjects ranged from two months to 21 years of age and received between 1 and 196 days of PN containing iron dextran. The mean dose of iron dextran in children decreased as the weight category increased from iron dextran can be safely administered to hospitalised children, and further studies are need to evaluate the potential to prevent iron deficiency anaemia and the need for additional IV iron infusions. © 2017 Dietitians Association of Australia.

  3. Magnetic catechin-dextran conjugate as targeted therapeutic for pancreatic tumour cells.

    Science.gov (United States)

    Vittorio, Orazio; Voliani, Valerio; Faraci, Paolo; Karmakar, Biswajit; Iemma, Francesca; Hampel, Silke; Kavallaris, Maria; Cirillo, Giuseppe

    2014-06-01

    Catechin-dextran conjugates have recently attracted a lot of attention due to their anticancer activity against a range of cancer cells. Magnetic nanoparticles have the ability to concentrate therapeutically important drugs due to their magnetic-spatial control and provide opportunities for targeted drug delivery. Enhancement of the anticancer efficiency of catechin-dextran conjugate by functionalisation with magnetic iron oxide nanoparticles. Modification of the coating shell of commercial magnetic nanoparticles (Endorem) composed of dextran with the catechin-dextran conjugate. Catechin-dextran conjugated with Endorem (Endo-Cat) increased the intracellular concentration of the drug and it induced apoptosis in 98% of pancreatic tumour cells placed under magnetic field. The conjugation of catechin-dextran with Endorem enhances the anticancer activity of this drug and provides a new strategy for targeted drug delivery on tumour cells driven by magnetic field. The ability to spatially control the delivery of the catechin-dextran by magnetic field makes it a promising agent for further application in cancer therapy.

  4. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Siposova, Katarina [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Pospiskova, Kristyna [Regional Centre of Advanced Technologies and Materials, Palacky University, Olomouc (Czech Republic); Bednarikova, Zuzana [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Department of Biochemistry, Faculty of Science, Safarik University, Kosice (Slovakia); Safarik, Ivo [Regional Centre of Advanced Technologies and Materials, Palacky University, Olomouc (Czech Republic); Department of Nanobiotechnology, Biology Centre, ISB, CAS, Ceske Budejovice (Czech Republic); Safarikova, Mirka [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Ceske Budejovice (Czech Republic); Kubovcikova, Martina; Kopcansky, Peter [Department of Magnetism, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Gazova, Zuzana, E-mail: gazova@saske.sk [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia)

    2017-04-01

    Protein transformation from its soluble state into amyloid aggregates is associated with amyloid-related diseases. Amyloid deposits of insulin fibrils have been found in the sites of subcutaneous insulin application in patients with prolonged diabetes. Using atomic force microscopy and ThT fluorescence assay we have investigated the interference of insulin amyloid aggregation with superparamagnetic Fe{sub 3}O{sub 4}-based nanoparticles (SPIONs) coated with dextran (DEX); molecular mass of dextran was equal to 15–20, 40 or 70 kDa. The obtained data indicate that all three types of dextran coated nanoparticles (NP-FeDEXs) are able to inhibit insulin fibrillization and to destroy amyloid fibrils. The extent of anti-amyloid activities depends on the properties of NP-FeDEXs, mainly on the size of nanoparticles which is determined by molecular mass of dextran molecules. The most effective inhibiting activity was observed for the smallest nanoparticles coated with 15–20 kDa dextran. Contrary, the highest destroying activity was observed for the largest NP-FeDEX (70 kDa dextran). - Highlights: • Interference of dextran- magnetite nanoparticles with insulin amyloid aggregation. • Nanoparticles inhibited insulin fibrillization and depolymerized insulin amyloid fibrils. • Size of nanoparticles significantly influences their anti-amyloid activities. • The most effective inhibition of insulin amyloid fibrillization was detected for the smallest nanoparticles. • Contrary, DC{sub 50} values decreased with increasing size of nanoparticles.

  5. The microsphere, the user and the architecture

    DEFF Research Database (Denmark)

    Suenson, Valinka; Harder, Henrik

    in a spatial setting which can be termed a micro sphere. A micro sphere emerges in the interaction between the users and architecture. Together these microspheres create what he calls a foam structure. This theory will be used in the analysis of the RFID tracking. Thus, the case study in the library...... of individual routes. The question asked in this paper is how the RFID registrations can show the multi functionality of a public space. Furthermore, how can architecture be seen as an active part in attracting valuable users? The use of RFID technology to register indoor movement patterns is a new...

  6. Characterization of iron oxide-dextran magnetic nanoparticle suspensions

    Science.gov (United States)

    Shih, J.; Bai, R.; Chiou, W.; Briber, R. M.; Borchers, J. A.; Dennis, C. L.; Gruettner, C.

    2011-03-01

    Magnetic nanoparticles, with structures from core-shell to nanocrystallites in a matrix, are candidates for use in biomedical applications. ``Superparamagnetic iron oxide'' (SPIO) nanoparticles are nanocrystallites of iron oxide in a dextran matrix, with sizes between 20nm and 250nm. Dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and hysteresis measurements were used for structural and magnetic characterization. Additionally, cryoquench-TEM was performed, allowing direct imaging without false aggregation from drying. The DLS-determined size of the particles is 250nm, but cryoquench-TEM yields a smaller size of 150nm. In addition, the particles are relatively well-dispersed, but dimers and trimers are observed. This corresponds with the evidence of weak interactions in magnetic hysteresis measurements. Further magnetic characterization will provide information on how the magnetic properties of these SPIO particles correlate with their size and structure.

  7. 3-hydroxyflavone-bovine serum albumin interaction in Dextran medium

    Directory of Open Access Journals (Sweden)

    Voicescu Mariana

    2015-01-01

    Full Text Available Spectroscopic analysis of a bioactive flavonol, 3-Hydroxyflavone (3-HF, in systems based on Dextran 70 (Dx70 (an important bio-relevant polysacharide and Bovine Serum Albumin (BSA (a carrier protein, have been studied by fluorescence and circular dichroism. Changes produced by different concentrations of Dx70 on the fluorescent characteristics of 3-HF, and on the excited - state intramolecular proton transfer (ESIPT process were studied. The influence of 3-HF binding and of Dx70 on the secondary structure of BSA were investigated by circular dichroism spectroscopy. The influence of temperature (30-80°C range on the intrinsic Tryptophan fluorescence in 3-HF/BSA/Dx70 systems, was investigated. The results are discussed with relevance to 3-HF as a sensitive fluorescence probe for exploring flavone-protein interaction in plasma expander media and also for its biological evaluation.

  8. Iron excretion in iron dextran-overloaded mice.

    Science.gov (United States)

    Musumeci, Marco; Maccari, Sonia; Massimi, Alessia; Stati, Tonino; Sestili, Paola; Corritore, Elisa; Pastorelli, Augusto; Stacchini, Paolo; Marano, Giuseppe; Catalano, Liviana

    2014-10-01

    Iron homeostasis in humans is tightly regulated by mechanisms aimed to conserve iron for reutilisation, with a negligible role played by excretory mechanisms. In a previous study we found that mice have an astonishing ability to tolerate very high doses of parenterally administered iron dextran. Whether this ability is linked to the existence of an excretory pathway remains to be ascertained. Iron overload was generated by intraperitoneal injections of iron dextran (1 g/kg) administered once a week for 8 weeks in two different mouse strains (C57bl/6 and B6D2F1). Urinary and faecal iron excretion was assessed by inductively coupling plasma-mass spectrometry, whereas cardiac and liver architecture was evaluated by echocardiography and histological methods. For both strains, 24-hour faeces and urine samples were collected and iron concentration was determined on days 0, 1 and 2 after iron administration. In iron-overloaded C57bl/6 mice, the faecal iron concentration increased by 218% and 157% on days 1 and 2, respectively (piron excreted represented a loss of 14% of total iron administered. Similar but smaller changes was also found in B6D2F1 mice. Conversely, we found no significant changes in the concentration of iron in the urine in either of the strains of mice. In both strains, histological examination showed accumulation of iron in the liver and heart which tended to decrease over time. This study indicates that mice have a mechanism for removal of excess body iron and provides insights into the possible mechanisms of excretion.

  9. Chitosan/dextran multilayer microcapsules for polyphenol co-delivery

    Energy Technology Data Exchange (ETDEWEB)

    Paini, Marco, E-mail: marco.paini@unige.it [Department of Civil, Chemical and Environmental Engineering, University of Genoa, via Opera Pia 15, 16145 Genoa (Italy); Research Center for Biologically Inspired Engineering in Vascular Medicine and Longevity (BELONG), Via Montallegro 1, 16145 Genoa (Italy); Aliakbarian, Bahar; Casazza, Alessandro A.; Perego, Patrizia [Department of Civil, Chemical and Environmental Engineering, University of Genoa, via Opera Pia 15, 16145 Genoa (Italy); Research Center for Biologically Inspired Engineering in Vascular Medicine and Longevity (BELONG), Via Montallegro 1, 16145 Genoa (Italy); Ruggiero, Carmelina; Pastorino, Laura [Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genoa, Via Opera Pia 13, 16145 Genoa (Italy)

    2015-01-01

    Polysaccharide-based nanostructured polymeric microcapsules were fabricated by the electrostatic layer-by-layer self-assembly technique and used to encapsulate mixtures of four different polyphenols in order to achieve their controlled release. The real-time fabrication of the dextran/chitosan multilayer was monitored by quartz crystal microbalance with dissipation monitoring, and the morphology of the nanostructured polymeric capsules was characterized by scanning electron microscopy. The polyphenol encapsulation was obtained by reversible permeability variation of the capsule shell in ethanol:water mixtures. The loading efficiency in different water:ethanol mixtures and the release rate in acidic conditions were characterized by UV spectroscopy and HPLC. The higher loading efficiency was obtained with an ethanol:water 35:65 phenolic solution, equal to 42.0 ± 0.6%, with a total release of 11.5 ± 0.7 mg of total polyphenols per 11.3 μL of microcapsules after 240 min of incubation in acidic environment. The results suggest that polysaccharide-based capsules can be successfully used to encapsulate and release low water-soluble molecules, such as polyphenols. - Highlights: • Chitosan/dextran nanocapsules were made by layer-by-layer self-assembly technique. • Different ethanol:water mixtures of four polyphenols were encapsulated. • An encapsulation efficiency of 42.0 ± 0.6% was obtained using ethanol:water 35:65. • Release profiles in acidic environment were monitored by UV spectroscopy and HPLC. • Nanocapsules had shown a complete release after 60 min in acidic environment.

  10. Iron excretion in iron dextran-overloaded mice

    Science.gov (United States)

    Musumeci, Marco; Maccari, Sonia; Massimi, Alessia; Stati, Tonino; Sestili, Paola; Corritore, Elisa; Pastorelli, Augusto; Stacchini, Paolo; Marano, Giuseppe; Catalano, Liviana

    2014-01-01

    Background Iron homeostasis in humans is tightly regulated by mechanisms aimed to conserve iron for reutilisation, with a negligible role played by excretory mechanisms. In a previous study we found that mice have an astonishing ability to tolerate very high doses of parenterally administered iron dextran. Whether this ability is linked to the existence of an excretory pathway remains to be ascertained. Materials and methods Iron overload was generated by intraperitoneal injections of iron dextran (1 g/kg) administered once a week for 8 weeks in two different mouse strains (C57bl/6 and B6D2F1). Urinary and faecal iron excretion was assessed by inductively coupling plasma-mass spectrometry, whereas cardiac and liver architecture was evaluated by echocardiography and histological methods. For both strains, 24-hour faeces and urine samples were collected and iron concentration was determined on days 0, 1 and 2 after iron administration. Results In iron-overloaded C57bl/6 mice, the faecal iron concentration increased by 218% and 157% on days 1 and 2, respectively (p<0.01). The iron excreted represented a loss of 14% of total iron administered. Similar but smaller changes was also found in B6D2F1 mice. Conversely, we found no significant changes in the concentration of iron in the urine in either of the strains of mice. In both strains, histological examination showed accumulation of iron in the liver and heart which tended to decrease over time. Conclusions This study indicates that mice have a mechanism for removal of excess body iron and provides insights into the possible mechanisms of excretion. PMID:24960657

  11. 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.

  12. Bioavailability enhancement of verapamil HCl via intranasal chitosan microspheres.

    Science.gov (United States)

    Abdel Mouez, Mamdouh; Zaki, Noha M; Mansour, Samar; Geneidi, Ahmed S

    2014-01-23

    Chitosan microspheres are potential drug carriers for maximizing nasal residence time, circumventing rapid mucociliary clearance and enhancing nasal absorption. The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres of verapamil hydrochloride (VRP) for intranasal delivery as an alternative to oral VRP which suffers low bioavailability (20%) due to extensive first pass effect. The microspheres were produced using a spray-drying and precipitation techniques and characterized for morphology (scanning electron microscopy), particle size (laser diffraction method), drug entrapment efficiency, thermal behavior (differential scanning calorimetry) and crystallinity (X-ray diffractometric studies) as well as in vitro drug release. Bioavailability of nasal VRP microspheres was studied in rabbits and the results were compared to those obtained after nasal, oral and intravenous administration of VRP solution. Results demonstrated that the microspheres were spherical with size 21-53 μm suitable for nasal deposition. The spray-drying technique was superior over precipitation technique in providing higher VRP entrapment efficiency and smaller burst release followed by a more sustained one over 6h. The bioavailability study demonstrated that the nasal microspheres exhibited a significantly higher bioavailability (58.6%) than nasal solution of VRP (47.8%) and oral VRP solution (13%). In conclusion, the chitosan-based nasal VRP microspheres are promising for enhancing VRP bioavailability by increasing the nasal residence time and avoiding the first-pass metabolism of the drug substance. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Interference of dextran in biuret-type assays of serum proteins.

    Science.gov (United States)

    Delanghe, Joris R; Hamers, Nicole; Taes, Youri E; Libeer, Jean-Claude

    2005-01-01

    Dextran interference in biuret-type assays of total serum proteins was investigated in a Belgian National External Quality Assurance Survey with 256 participants. In vitro supplementation of therapeutic (10% Gentran 70) dextran concentrations showed a broadly varying (from 0 to 20%) negative interference. The analytical interference was found to depend on both the sodium hydroxide and tartrate concentrations in the reagent formulation. The dry chemistry biuret method was not affected by the dextran interference. In a number of cases, the effects observed may be of clinical importance. Both clinicians and laboratory staff should be aware of the persistence of this analytical problem.

  14. Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and ?-cyclodextrin polymers

    OpenAIRE

    Nielsen, Thorbj?rn Terndrup; Amiel, Catherine; Duroux, Laurent; Larsen, Kim Lambertsen; St?de, Lars Wagner; Wimmer, Reinhard; Wintgens, V?ronique

    2015-01-01

    Novel (S)-camptothecin–dextran polymers were obtained by “click” grafting of azide-modified (S)-camptothecin and alkyne-modified dextrans. Two series based on 10 kDa and 70 kDa dextrans were prepared with a degree of substitution of (S)-camptothecin between 3.1 and 10.2%. The binding properties with β-cyclodextrin and β-cyclodextrin polymers were measured by isothermal titration calorimetry and fluorescence spectroscopy, showing no binding with β-cyclodextrin but high binding with β-cyclodext...

  15. Mucoadhesivity Characterization of Isabgol Husk Mucilage Microspheres Crosslinked by Glutaraldehyde.

    Science.gov (United States)

    Sharma, Vipin Kumar; Sharma, Prince Prashant; Mazumder, Bhasker; Bhatnagar, Aseem; Singh, Thakuri

    2015-01-01

    The microspheres of Isabgol husk were prepared by emulsification-crosslinking technique and the gastrointestinal transition behavior of the formulation was studied by gamma scintigraphy. The impact of different process variables such as amount of glutaraldehyde, concentration of Isabgol husk and temperature was studied on surface morphology and mucoadhesion. In vitro mucoadhesive testing of formulations was performed by determination of zeta potential, mucus glycoprotein assay and mucus adsorption isotherms. The effect of feeding on retention of microspheres in the gastrointestinal track (GIT) was studied in albino rabbits by gamma scintigraphy study. The results indicated the formation of microspheres as observed by scanning electron microscopy. The smooth and round surfaces of microspheres were obtained on increasing Isabgol husk and glutaraldehyde amount. The positive zeta potential of all formulations indicated the electrostatic interaction as a mechanism of mucoadhesion between the mucus of GIT membranes and the microspheres surfaces. The influence of electrostatic interaction on mucoadhesion of microspheres was again ascertained when the mucin equilibrium adsorption on preparations indicated well fitness in Langmuir and Freundlich adsorption isotherms. During gamma scintigraphy, the stability of (99m)Tc-sodium pertechnetate was found 98.82% at pH 6.8 and 96.78% at pH 7.2, respectively. It indicated the minimal leaching of bound radionuclide from microspheres during gastrointestinal transition as observed in gamma scintigraphic images of the rabbits. The microspheres retained in GIT even after 24 hrs of oral administration. The results indicated the applicability of Isabgol husk mucilage in the development of mucoadhesive microspheres.

  16. Protocell-like Microspheres from Thermal Polyaspartic Acid

    Science.gov (United States)

    Bahn, Peter R.; Pappelis, Aristotel; Bozzola, John

    2006-12-01

    One of the most prominent amino acids to appear in monomer-generating origin-of-life experiments is aspartic acid. Hugo Schiff found in 1897 that aspartic acid polymerizes when heated to form polyaspartylimide which hydrolyzes in basic aqueous solution to form thermal polyaspartic acid which is a branched polypeptide. We recently reported at the ISSOL 2005 Conference that commercially made thermal polyaspartic acid forms microspheres when heated in boiling water and allowed to cool. In a new experiment we heated aspartic acid at 180°C for up to 100 h to form thermal polyaspartylimide which when heated in boiling water without addition of base hydrolyzed to form thermal polyaspartic acid which upon cooling formed microspheres. Thermal polyaspartic acid microspheres appear protocell-like in the sense of being prebiotically plausible lattices or containers that could eventually have been filled with just the right additions of primordial proteins, nucleic acids, lipids, and metabolites so as to constitute protocells capable of undergoing further chemical and biological evolution. Thermal polyaspartic acid microspheres are extremely simple models of protocells that are more amenable to precise quantitative experimental investigation than the proteinoid microspheres of Sidney W. Fox. We present here scanning electron microscope images of such thermal polyaspartic acid microspheres. Figure 1 shows thermal polyaspartic acid microspheres from l-aspartic acid heated at 180°C for 50 h, at a magnification of 3,500×. Figure 2 shows thermal polyaspartic acid microspheres from the same sample at a magnification of 7,000×. The thermal polyaspartic acid microspheres have a diameter of approximately 1 μm These images were viewed with a Hitachi S2460N scanning electron microscope at 20 kV acceleration voltage. [Figure not available: see fulltext.][Figure not available: see fulltext.

  17. 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).

  18. Egg albumin microspheres containing paracetamol for oral administration. I. In vitro characterization.

    Science.gov (United States)

    Torrado, J J; Illum, L; Cadorniga, R; Davis, S S

    1990-01-01

    Different egg albumin microsphere systems for oral administration of paracetamol were prepared by the emulsion and capillary extrusion methods. The size of the microspheres depended on the method used to produce the microcapsules and also the size of the crystals of paracetamol. The effect of the following factors on in vitro dissolution were studied: different denaturation processes, variation in the ratio of paracetamol to albumin, size of microspheres, remnant oil in the microspheres, and the coating of the microspheres with membranes of polymethacrylates (Eudragit). The most important factors to control the release of paracetamol from the microspheres were the denaturation process and the use of waxes and membranes to delay the release of paracetamol from the microspheres. The egg albumin microspheres were very porous and permeable to water and thus the release of the paracetamol from the matrix was usually fast unless the microspheres were suitably coated, with, for example, Eudragit RL or RS.

  19. Surface functionalization of magnetic nanoparticles formed by self-associating hydrophobized oxidized dextrans

    Science.gov (United States)

    Farber, Shimon; Ickowicz, Diana E.; Melnik, Kristie; Yudovin-Farber, Ira; Recko, Daniel; Rampersaud, Arfaan; Domb, Abraham J.

    2014-06-01

    Magnetic iron oxide nanoparticles surface covered with oleic acid layer followed by a second layer of hydrophobized oxidized dextran aldehyde were prepared and tested for physico-chemical properties and ligand- and cell-specific binding. It was demonstrated that oleic acid-iron oxide nanoparticles coated with an additional layer of hydrophobized oxidized dextran were dispersible in buffer solutions and possess surface aldehyde active groups available for further binding of ligands or markers via imine or amine bond formation. Hydrophobized dextrans were synthesized by periodate oxidation and conjugation of various alkanamines to oxidized dextran by imination. Physico-chemical properties, as separation using magnetic field, magnetite concentration, and particle diameter, of the prepared magnetic samples are reported. The biotin-binding protein, neutravidin, was coupled to the particle surface by a simple reductive amination procedure. The particles were used for specific cell separation with high specificity.

  20. Probing Conformational Change of Bovine Serum Albumin–Dextran Conjugates under Controlled Dry Heating

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Shuqin; Li, Yunqi; Zhao, Qin; Li, Ji; Xia, Qiuyang; Zhang, Xiaoming; Huang, Qingrong (Rutgers); (Chinese Aca. Sci.); (Jiangnan)

    2015-04-29

    The time-dependent conformational change of bovine serum album (BSA) during Maillard reaction with dextran under controlled dry heating has been studied by small-angle X-ray scattering, fluorescence spectroscopy, dynamic light scattering, and circular dichroism analysis. Through the research on the radii of gyration (Rg), intrinsic fluorescence, and secondary structure, conjugates with dextran coating were found to inhibit BSA aggregation and preserve the secondary structure of native BSA against long-time heat treatment during Maillard reaction. The results suggested that the hydrophilic dextran was conjugated to the compact protein surface and enclosed it and more dextran chains were attached to BSA with the increase of the heating time. The study presented here will be beneficial to the understanding of the conformational evolution of BSA molecules during the dry-heating Maillard reaction and to the control of the protein–polysaccharide conjugate structure.

  1. Specific MR imaging of human-lymphocytes by monoclonal antibody-guided dextran-magnetite particles

    NARCIS (Netherlands)

    Bulte, J. W. M.; Hoekstra, Y; Kamman, R. L.; Magin, R. L.; Webb, A. G.; Briggs, R. W.; Go, K. G.; Hulstaert, C. E.; Miltenyi, S.; The, T. Hauw; de Leij, L

    Human lymphocytes were labeled with biotinylated anti-lymphocyte-directed monoclonal antibodies, to which streptavidin and subsequently biotinylated dextran-magnetite particles were coupled. This labeling resulted in a strong and selective negative contrast enhancement of lymphocyte suspensions at

  2. Iron dextran in the treatment of iron-deficiency anaemia of pregnancy

    African Journals Online (AJOL)

    1991-02-16

    deficiency anaemia were randomly allocated to two treatment groups. Group A received the usual recom. mended dose of iron dextran (Imferon; Fisons) and group 8 received two-thirds of the recommended dose. A further 30 patients ...

  3. Crystallization and preliminary X-ray analysis of Streptococcus mutans dextran glucosidase

    Energy Technology Data Exchange (ETDEWEB)

    Saburi, Wataru; Hondoh, Hironori, E-mail: hondoh@abs.agr.hokudai.ac.jp [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan); Unno, Hideaki [Faculty of Engineering, Nagasaki University, Bunkyo-machi, Nagasaki 852-8521 (Japan); Okuyama, Masayuki; Mori, Haruhide [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan); Nakada, Toshitaka [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Matsuura, Yoshiki [Institute for Protein Research, Osaka University, Suita, Osaka 565-0871 (Japan); Kimura, Atsuo [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan)

    2007-09-01

    Dextran glucosidase from S. mutans was crystallized using the hanging-drop vapour-diffusion method. The crystals diffracted to 2.2 Å resolution. Dextran glucosidase from Streptococcus mutans is an exo-hydrolase that acts on the nonreducing terminal α-1,6-glucosidic linkage of oligosaccharides and dextran with a high degree of transglucosylation. Based on amino-acid sequence similarity, this enzyme is classified into glycoside hydrolase family 13. Recombinant dextran glucosidase was purified and crystallized by the hanging-drop vapour-diffusion technique using polyethylene glycol 6000 as a precipitant. The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 72.72, b = 86.47, c = 104.30 Å. A native data set was collected to 2.2 Å resolution from a single crystal.

  4. Elongation of fibers from highly viscous dextran solutions enables fabrication of rapidly dissolving drug carrying fabrics.

    Science.gov (United States)

    Frampton, John P; Lai, David; Lounds, Maxwell; Chung, Kyeongwoon; Kim, Jinsang; Mansfield, John F; Takayama, Shuichi

    2015-01-28

    A simple method is presented for forming thread-like fibers from highly viscous dextran solutions. Based on the cohesive and adhesive forces between a dextran solution and the substrate to which it is applied, multiple fibers of approximately 10 μm in diameter can be elongated simultaneously. These fibers can be woven into multiple layers to produce fabrics of varying fiber orientations and mechanical properties. Various bioactive agents can be incorporated into the dextran solution prior to fiber formation, including hemostatic and antibiotic agents. Fabrics containing thrombin are capable of coagulating human platelet poor plasma in vitro. Fabrics containing antibiotics are capable of suppressing bacterial growth in a disk diffusion assay. These data suggest that this new material composed entirely of dextran has promise as a drug delivery component in wound dressings. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The Influence of Ghrelin on the Development of Dextran Sodium Sulfate-Induced Colitis in Rats

    National Research Council Canada - National Science Library

    Matuszyk, Aleksandra; Ceranowicz, Dagmara; Warzecha, Zygmunt; Ceranowicz, Piotr; Fyderek, Krzysztof; Gałązka, Krystyna; Cieszkowski, Jakub; Bonior, Joanna; Jaworek, Jolanta; Pihut, Małgorzata; Dembiński, Artur

    2015-01-01

    Ghrelin has protective and therapeutic effects in the gut. The aim of present studies was to investigate the effect of treatment with ghrelin on the development of colitis evoked by dextran sodium sulfate (DSS). Methods...

  6. Effect of intravenous iron-dextran (Imferon) infusion on antigen induced monarticular arthritis in rabbits.

    OpenAIRE

    Kind, C N; Blackham, A; Morris, C J

    1992-01-01

    The effect of intravenously infused iron-dextran (Imferon) on the progression of antigen induced monarticular arthritis in rabbits was studied. A rapid deposition of iron and apoferritin in the synovia of arthritis joints occurred after infusion of iron-dextran during either the acute or chronic phases of the disease. This coincided with the appearance of catalytic (bleomycin reactive) iron in the synovial fluid. There was no evidence, however, for an exacerbation of the antigen induced arthr...

  7. Hybrid dextran-iron oxide thin films deposited by laser techniques for biomedical applications

    OpenAIRE

    Predoi, Daniela; Ciobanu, Carmen Steluta; Mihaela RADU; Costache, Marieta; Dinischiotu, Anca; Gyorgy, Eniko

    2012-01-01

    Iron oxide nanoparticles were prepared by chemical co-precipitation method. The nanoparticles were mixed with dextran in distilled water. The obtained solutions were frozen in liquid nitrogen and used as targets during matrix assisted pulsed laser evaporation for the growth of hybrid, iron oxide nanoparticles-dextran thin films. Fourier Transform Infrared Spectroscopy and X-ray diffraction investigations revealed that the obtained films preserve the structure and composition of the initial, n...

  8. Influence of Blood Viscosity on Blood Flow and the Effect of Low Molecular Weight Dextran

    Science.gov (United States)

    Dormandy, John A.

    1971-01-01

    Changes in whole blood viscosity are related to changes in the leg blood flow during infusions of low-molecular-weight dextran and Hartmann's solution. A close inverse correlation exists between changes in viscosity and blood flow, the change in blood flow being about three times greater than the change in blood viscosity. The dextran and Hartmann's solution had a similar effect on blood viscosity and blood flow if corrections are made for the difference in haemodilution. PMID:5129616

  9. One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles

    OpenAIRE

    Hussain,Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Tahir, Muhammad Nawaz; Shah, Muhammad Raza; Ahmed, Riaz; Bukhari, Syed Nasir Abbas

    2014-01-01

    Background Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. Results UV–vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron...

  10. Resonant microsphere gyroscope based on a double Faraday rotator system.

    Science.gov (United States)

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  11. [Study on the lung targeting gelatin microspheres of streptomycin sulphate].

    Science.gov (United States)

    Zhang, Z; Lu, B; Shu, G; Xie, H; Yi, Q; He, Y; Wang, J

    1995-06-01

    This paper is reported the technology of lung targeting gelatin microspheres of streptomycin sulphate (SMS). The microspheres were prepared with natural biodegradable gelatin as the load material and castor oil as the oil phase. The experimental conditions were optimized, the mean volume diameter obtained being 9.7 microns and the mean rate of encapsulation 15.69%. The content, shape and size of the microspheres showed no remarkable change after storage at 37 degrees C RH 75% for 3 months. Activation energy of heat decomposition E = 75.86kJ/mol. In vitro, the SMS release rate was found to accord with Higuchi equation with t1/2 = 8.6h. In vivo (rabbits) the gelatin microspheres were proved to be concentrated in the lung.

  12. Cell Microencapsulation in Polyethylene Glycol Hydrogel Microspheres Using Electrohydrodynamic Spraying.

    Science.gov (United States)

    Imaninezhad, Mozhdeh; Jain, Era; Zustiak, Silviya Petrova

    2017-08-03

    Microencapsulation of cells is beneficial for various biomedical applications, such as tissue regeneration and cell delivery. While a variety of techniques can be used to produce microspheres, electrohydrodynamic spraying (EHS) has shown promising results for the fabrication of cell-laden hydrogel microspheres in a wide range of sizes and in a relatively high-throughput manner. Here we describe an EHS technique for the fabrication of cell-laden polyethylene glycol (PEG) microspheres. We utilize mild hydrogel gelation chemistry and a combination of EHS parameters to allow for cell microencapsulation with high efficiency and viability. We also give examples on the effect of different EHS parameters such as inner diameter of the needle, voltage and flow rate on microsphere size and encapsulated cell viability.

  13. 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 ...

  14. 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.

  15. Modulating the Synthesis of Dextran with the Acceptor Reaction Using Native and Encapsulated Dextransucrases

    Directory of Open Access Journals (Sweden)

    Arantza Gómez de Segura

    2004-01-01

    Full Text Available Dextransucrases are glucansucrases with broad applications in the food, cosmetics and pharmaceutical industries. Using sucrose as the glucosyl donor, they synthesize both high molecular weight (HMW dextrans and potential prebiotic oligosaccharides. The process selectivity can be modulated by varying the reaction conditions. When no other molecule is present in the reaction, only dextrans are synthesized. In the presence of methyl α-D-glucopyranoside, the synthesis of methyl polyglucosides takes place, diminishing the transfer of glucose molecules to form dextran. In this work, the formation of HMW soluble dextran and methyl polyglucosides was studied with dextransucrases from Leuconostoc mesenteroides, strains B-512F and B-1299. The amount of dextran formed with dextransucrase B-512F was reduced up to 4 % with respect to the control in absence of acceptor, using a mass ratio of sucrose:methyl α-D-glucopyranoside of 1:4. The encapsulation in alginate retains the dextran inside the beads, causing a distortion of the biocatalyst and finally releasing the polysaccharides into the reaction medium.

  16. An efficient acetylation of dextran using in situ activated acetic anhydride with iodine

    Directory of Open Access Journals (Sweden)

    MUHAMMAD A. HUSSAIN

    2010-02-01

    Full Text Available A facile, efficient, cost-effective and solvent-free acetylation method has been developed for the acetylation of dextran. Dextran acetates were successfully synthesized using different molar ratios of acetic anhydride in the presence of iodine as a catalyst without the use of any solvent. The reactions were realized at 50 °C for 3 h under stirring and nitrogen. This efficient method yielded highly pure and organosoluble dextran esters. The reaction appears highly effective for obtaining higher degrees of substitution (DS with great efficiency. Under solvent-free conditions, dextran triacetates were efficiently synthesized. It was also observed that the molar ratio can easily control the DS of pendant groups onto the polymer backbone. Hence, a range of products with varying DS were successfully designed, purified and characterized. Covalent attachment of the pendant groups onto the polymer backbone was verified by spectroscopic techniques. Thermogravimetric analysis indicated that the obtained dextran esters were thermally as stable as dextran. The DS of the pendant groups onto the polymer backbone was calculated using standard acid base titration after saponification. Furthermore, all products were thoroughly characterized by thermal analysis (TG and DTG, and FTIR and 1H-NMR spectroscopic analysis.

  17. Effects of dextran on five biuret-based procedures for total protein in serum.

    Science.gov (United States)

    Barnes, D B; Pierce, G F; Lichti, D; Landt, M; Koenig, J; Chan, K M

    1985-12-01

    We evaluated the effect of dextran on values for total protein in serum as measured by the biuret method with five widely used automated instruments: the American Monitor Parallel; the Du Pont aca II; the Roche Cobas-Bio; the Kodak Ektachem 400; and the Beckman Astra 8. Dextran concentrations as great as 25 or 30 g/L had relatively little or no influence on total protein measurements by the latter three instruments. Dextran concentrations exceeding 6 g/L caused falsely low results with the aca, whereas the Parallel gave falsely high results when the dextran concentration exceeded 2 g/L. The aca total protein procedure could be protected from the interference by dextran concentrations up to 30 g/L by injecting 0.4-0.8 mL of ethylene glycol directly into the reagent pack before sampling. However, we could not eliminate the interference with the Parallel procedure by any simple means; we thus recommend that it not be used for measuring total protein in serum samples from patients who are being treated with dextran.

  18. Dextrans produced by lactic acid bacteria exhibit antiviral and immunomodulatory activity against salmonid viruses.

    Science.gov (United States)

    Nácher-Vázquez, Montserrat; Ballesteros, Natalia; Canales, Ángeles; Rodríguez Saint-Jean, Sylvia; Pérez-Prieto, Sara Isabel; Prieto, Alicia; Aznar, Rosa; López, Paloma

    2015-06-25

    Viral infections in the aquaculture of salmonids can lead to high mortality and substantial economic losses. Thus, there is industrial interest in new molecules active against these viruses. Here we describe the production, purification, and the physicochemical and structural characterization of high molecular weight dextrans synthesized by Lactobacillus sakei MN1 and Leuconostoc mesenteroides RTF10. The purified dextrans, and commercial dextrans with molecular weights ranging from 10 to 2000kDa, were assayed in infected BF-2 and EPC fish cell-line monolayers for antiviral activity. Only T2000 and dextrans from MN1 and RTF10 had significant antiviral activity. This was similar to results obtained against infectious pancreatic necrosis virus. However the dextran from MN1 showed ten-fold higher activity against hematopoietic necrosis virus than T2000. In vivo assays using the MN1 polymer confirmed the in vitro results and revealed immunomodulatory activity. These results together with the high levels of dextran production (2gL(-1)) by Lb. sakei MN1, indicate the compounds potential utility as an antiviral agent in aquaculture. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    Science.gov (United States)

    Siposova, Katarina; Pospiskova, Kristyna; Bednarikova, Zuzana; Safarik, Ivo; Safarikova, Mirka; Kubovcikova, Martina; Kopcansky, Peter; Gazova, Zuzana

    2017-04-01

    Protein transformation from its soluble state into amyloid aggregates is associated with amyloid-related diseases. Amyloid deposits of insulin fibrils have been found in the sites of subcutaneous insulin application in patients with prolonged diabetes. Using atomic force microscopy and ThT fluorescence assay we have investigated the interference of insulin amyloid aggregation with superparamagnetic Fe3O4-based nanoparticles (SPIONs) coated with dextran (DEX); molecular mass of dextran was equal to 15-20, 40 or 70 kDa. The obtained data indicate that all three types of dextran coated nanoparticles (NP-FeDEXs) are able to inhibit insulin fibrillization and to destroy amyloid fibrils. The extent of anti-amyloid activities depends on the properties of NP-FeDEXs, mainly on the size of nanoparticles which is determined by molecular mass of dextran molecules. The most effective inhibiting activity was observed for the smallest nanoparticles coated with 15-20 kDa dextran. Contrary, the highest destroying activity was observed for the largest NP-FeDEX (70 kDa dextran).

  20. Water Kefir grain as a source of potent dextran producing lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Davidović Slađana Z.

    2015-01-01

    Full Text Available Water kefir is abeverage fermented by a microbial consortium captured in kefir grains. The kefir grains matrix is composed of polysaccharide, primarily dextran, whichis produced by members of the microbial consortium. In this study, we have isolated lactic acid bacteria (LAB from non-commercial water kefir grains (from Belgrade, Serbia and screened for dextran production. Among twelve Lisolates threeproduced slime colonies on modified MRS (mMRS agar containing sucrose instead of glucoseand were presumed to produce dextran. Three LABwere identified based on morphological, physiological and biochemical characteristics and 16S rRNA sequencing as Leuconostoc mesenteroides(strains T1 and T3 and Lactobacillus hilgardii (strain T5. The isolated strains were able to synthesize a substantial amount of dextran in mMRS broth containing 5% sucrose. Maximal yields (11.56, 18.00 and 18.46 g/l were obtained after 16h, 20h and 32h for T1, T3 and T5, respectively. Optimal temperature for dextran production was 23oC for two Leuconostoc mesenteroides strains and 30oC for Lactobacillus hilgardii strain. The produced dextrans were identified based on paper chromatography while the main structure characteristics of purified dextranwere observed by FT-IR spectroscopy. Our study shows that water kefir grains are a natural source of potent dextranproducing LAB. [Projekat Ministarstva nauke Republike Srbije, br. TR 31035

  1. Construction of a dextran-free Leuconostoc citreum mutant by targeted disruption of the dextransucrase gene.

    Science.gov (United States)

    Jin, Q; Li, L; Kim, Y J; Han, N S

    2014-10-01

    Leuconostoc citreum is an important lactic acid bacterium in fermented foods, but dextran production often causes undesired ropiness. To prevent this side effect, a dextran-free mutant needs to be created. Homologous recombination of the dextransucrase gene (dsrC) was conducted using a segregationally unstable plasmid, pCBM32-DSUDs. A mutant was obtained on sucrose agar medium, and a site-specific insertional inactivation in the gene was confirmed. When cultured in sucrose medium, the mutant strain produced no dextransucrase or dextran. Additionally, it showed a longer lag phase (9 h) than the wild-type strain (3 h), providing new insights into the role of dextransucrase in carbohydrate metabolism of Leuconostoc. In this study, a dextransucrase knockout mutant was constructed. It was found that Leuc. citreum dextransucrase not only synthesizes dextran for cell protection but also provides fructose as an important carbon source for cell growth. This knockout mutation was generated for the first time in Leuc. citreum. The dextran-free mutant has the potential to be used for various industrial purposes, including as a starter culture for production of nonviscous fermented foods and as a dextran-free host for production of recombinant proteins. © 2014 The Society for Applied Microbiology.

  2. Mucoadhesive Microspheres of Famotidine for Gastro Retentive Drug Delivery

    OpenAIRE

    Koland Marina; Jacob Ansu; Prabhu Prabhakara; Shetty Nisha Girish

    2012-01-01

    Famotidine, a histamine H2 receptor antagonist is absorbed only in the initial part of gastro intestinal (GI) tract and has less bioavailability. Hence the drug was formulated as gastro-retentive drug delivery systems in the form of mucoadhesive microspheres to prolong its residence time in the stomach and improve its absorption. The microspheres of famotidine were prepared by emulsification-ionic gelation technique using mucoadhesive polymers such as Sodium Alginate, Carbopol 934P and HPMC i...

  3. Uniform double-walled polymer microspheres of controllable shell thickness.

    Science.gov (United States)

    Berkland, Cory; Pollauf, Emily; Pack, Daniel W; Kim, Kyekyoon

    2004-04-16

    A method for fabricating uniform double-walled microspheres with controllable size and shell thickness has been developed. The method, based on previous work to fabricate uniform microspheres, employs multiple concentric nozzles to produce a smooth coaxial jet comprising an annular shell and core material, which is acoustically excited to break up into uniform core-shell droplets. The orientation of the jets, material flow rates, and rate of solvent extraction are controlled to create uniform and well-centered "double-walled" microspheres exhibiting a controllable shell thickness. Double-walled microspheres were fabricated with different arrangements of bulk-eroding poly(D,L-lactide-co-glycolide) (PLG) and surface-eroding poly[(1,6-bis-carboxyphenoxy) hexane] (PCPH). Variation of the fabrication parameters allowed complete encapsulation by the shell phase, including the efficient formation of a PCPH shell encapsulating a PLG core. Utilizing this technology, double-walled microsphere shell thickness can be varied from core encapsulation for double-walled microspheres near 50 microm in overall diameter.

  4. Abiogenic Photophosphorylation of ADP to ATP Sensitized by Flavoproteinoid Microspheres

    Science.gov (United States)

    Kolesnikov, Michael P.; Telegina, Taisiya A.; Lyudnikova, Tamara A.; Kritsky, Mikhail S.

    2008-06-01

    A model for abiogenic photophosphorylation of ADP by orthophosphate to yield ATP was studied. The model is based on the photochemical activity of flavoproteinoid microspheres that are formed by aggregation in an aqueous medium of products of thermal condensation of a glutamic acid, glycine and lysine mixture (8:3:1) and contain, along with amino acid polymers (proteinoids), abiogenic isoalloxazine (flavin) pigments. Irradiation of aqueous suspensions of microspheres with blue visible light or ultraviolet in the presence of ADP and orthophosphate resulted in ATP formation. The yield of ATP in aerated suspensions was 10 20% per one mol of starting ADP. Deaeration reduced the photophosphorylating activity of microspheres five to 10 times. Treatment of aerated microsphere suspensions with superoxide dismutase during irradiation partially suppressed ATP formation. Deaerated microspheres restored completely their photophosphorylating activity after addition of hydrogen peroxide to the suspension. The photophosphorylating activity of deaerated suspensions of flavoproteinoid microspheres was also recovered by introduction of Fe3+-cytochrome c, an electron acceptor alternative to oxygen. On the basis of the results obtained, a chemical mechanism of phosphorylation is proposed in which the free radical form of reduced flavin sensitizer left( {{text{FlH}}^ bullet } right) and ADP are involved.

  5. 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.

  6. Permeability of Hollow Microspherical Membranes to Helium

    Science.gov (United States)

    Zinoviev, V. N.; Kazanin, I. V.; Pak, A. Yu.; Vereshchagin, A. S.; Lebiga, V. A.; Fomin, V. M.

    2016-01-01

    This work is devoted to the study of the sorption characteristics of various hollow microspherical membranes to reveal particles most suitable for application in the membrane-sorption technologies of helium extraction from a natural gas. The permeability of the investigated sorbents to helium and their impermeability to air and methane are shown experimentally. The sorption-desorption dependences of the studied sorbents have been obtained, from which the parameters of their specific permeability to helium are calculated. It has been established that the physicochemical modification of the original particles exerts a great influence on the coefficient of the permeability of a sorbent to helium. Specially treated cenospheres have displayed high efficiency as membranes for selective extraction of helium.

  7. Microspheres and Nanotechnology for Drug Delivery.

    Science.gov (United States)

    Jóhannesson, Gauti; Stefánsson, Einar; Loftsson, Thorsteinn

    2016-01-01

    Ocular drug delivery to the posterior segment of the eye can be accomplished by invasive drug injections into different tissues of the eye and noninvasive topical treatment. Invasive treatment involves the risks of surgical trauma and infection, and conventional topical treatments are ineffective in delivering drugs to the posterior segment of the eye. In recent years, nanotechnology has become an ever-increasing part of ocular drug delivery. In the following, we briefly review microspheres and nanotechnology for drug delivery to the eye, including different forms of nanotechnology such as nanoparticles, microparticles, liposomes, microemulsions and micromachines. The permeation barriers and anatomical considerations linked to ocular drug delivery are discussed and a theoretical overview on drug delivery through biological membranes is given. Finally, in vitro, in vivo and human studies of x03B3;-cyclodextrin nanoparticle eyedrop suspensions are discussed as an example of nanotechnology used for drug delivery to the eye. © 2016 S. Karger AG, Basel.

  8. Minimally invasive transdermal delivery of iron-dextran.

    Science.gov (United States)

    Juluri, Abhishek; Modepalli, Naresh; Jo, Seongbong; Repka, Michael A; Shivakumar, H Nanjappa; Murthy, S Narasimha

    2013-03-01

    Iron deficiency is one of the most prevalent and serious health issues among people all over the world. Iron-dextran (ID) colloidal solution is one among the very few US Food and Drug Administration (FDA)-approved iron sources for parenteral administration of iron. Parenteral route does not allow frequent administration because of its invasiveness and other associated complications. The main aim of this project was to investigate the plausibility of transdermal delivery of ID facilitated by microneedles, as an alternative to parenteral iron therapy. In vitro permeation studies were carried out using freshly excised hairless rat abdominal skin in a Franz diffusion apparatus. Iron repletion studies were carried out in hairless anemic rat model. The anemic rats were divided into intact skin (control), microneedle pretreated, and intraperitoneal (i.p.) groups depending on the mode of delivery of iron. The hematological parameters were measured intermittently during treatment. There was no improvement in the hematological parameters in case of control group, whereas, in case of microneedle pretreated and i.p. group, there was significant improvement within 2-3 weeks. The results suggest that microneedle-mediated delivery of ID could be developed as a potential treatment method for iron-deficiency anemia. Copyright © 2012 Wiley Periodicals, Inc.

  9. Dextran sulfate nanoparticles as a theranostic nanomedicine for rheumatoid arthritis.

    Science.gov (United States)

    Heo, Roun; You, Dong Gil; Um, Wooram; Choi, Ki Young; Jeon, Sangmin; Park, Jong-Sung; Choi, Yuri; Kwon, Seunglee; Kim, Kwangmeyung; Kwon, Ick Chan; Jo, Dong-Gyu; Kang, Young Mo; Park, Jae Hyung

    2017-07-01

    With the aim of developing nanoparticles for targeted delivery of methotrexate (MTX) to inflamed joints in rheumatoid arthritis (RA), an amphiphilic polysaccharide was synthesized by conjugating 5β-cholanic acid to a dextran sulfate (DS) backbone. Due to its amphiphilic nature, the DS derivative self-assembled into spherical nanoparticles (220 nm in diameter) in aqueous conditions. The MTX was effectively loaded into the DS nanoparticles (loading efficiency: 73.0%) by a simple dialysis method. Interestingly, the DS nanoparticles were selectively taken up by activated macrophages, which are responsible for inflammation and joint destruction, via scavenger receptor class A-mediated endocytosis. When systemically administrated into mice with experimental collagen-induced arthritis (CIA), the DS nanoparticles effectively accumulated in inflamed joints (12-fold more than wild type mice (WT)), implying their high targetability to RA tissues. Moreover, the MTX-loaded DS nanoparticles exhibited significantly improved therapeutic efficacy against CIA in mice compared to free MTX alone. Overall, the data presented here indicate that DS nanoparticles are potentially useful nanomedicines for RA imaging and therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Photocrosslinkable bioadhesive based on dextran and PEG derivatives.

    Science.gov (United States)

    Li, Chunxia; Wang, Tao; Hu, Lihui; Wei, Yaohua; Liu, Jianning; Mu, Xueyan; Nie, Jun; Yang, Dongzhi

    2014-02-01

    In this study, a hybrid photopolymeric bioadhesive system consisting of urethane methacrylated dextran (Dex-U) and 3, 4-Dihydroxyphenyl-l-alanine (DOPA) modified three-arm poly (ethylene glycol) s (PEG-DOPAs) was designed. The process of photopolymerization was detected by Photo-Differential Scanning Calorimetry (Photo-DSC). The adhesion strength was evaluated by the lap shear tests. The surface tension of the solutions, burst pressures and the cytotoxicity assays were also investigated. The addition of PEG-DOPAs significantly improved the properties of Dex-U especially in the field of adhesion strength and burst pressure. And materials variation could be tailored to match the demands for tissue repair. Compared to the Dex-U systems, the maximum adhesion strength of the copolymeric system increased from 2.7±0.1 MPa to 4.0±0.6 MPa. Owing to its strong adhesion strength, rapid curing rate and good biocompatibility, such photocrosslinkable hydrogelsa could be applied to the areas of bioadhesive. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  11. Amphiphilic photosensitive dextran-g-poly(o-nitrobenzyl acrylate) glycopolymers.

    Science.gov (United States)

    Soliman, Soliman Mehawed Abdellatif; Colombeau, Ludovic; Nouvel, Cécile; Babin, Jérôme; Six, Jean-Luc

    2016-01-20

    Among all photosensitive monomers reported in the literature, o-nitrobenzyl acrylate (NBA) was selected in this present study. Two strategies were compared to produce azido-terminated poly(o-nitrobenzyl acrylate) (PNBA) using controlled Single Electron Transfer-Living Radical Polymerization (SET-LRP). In a parallel way, dextran (Dex) was modified by the introduction of several alkynyl-terminated hydrophobic chains. Finally, an Huisgen-type Copper (I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) click-chemistry was carried out to produce amphiphilic Dex-g-PNBA glycopolymers with different number and length of PNBA grafts. 2D DOSY (1)H NMR was used to prove the formation of such glycopolymers. Preliminary study on Dex-g-PNBA self-assembly was done by measuring the critical water content (CWC) above which Dex-g-PNBA started to auto-organize themselves to produce nano-objects. Finally, under UV irradiation, PNBA grafts turn into poly(acrylic acid) ones giving light-sensitive properties to such amphiphilic Dex-g-PNBA. Such properties were evaluated and compared with those of PNBA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Biomedical properties and preparation of iron oxide-dextran nanostructures by MAPLE technique

    Directory of Open Access Journals (Sweden)

    Ciobanu Carmen

    2012-03-01

    Full Text Available Abstract Background In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs. The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz was used for the growth of the hybrid, iron oxide NPs-dextran thin films. Results Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p3/2 of two thin films of dextran coated iron oxide is consistent with Fe3+ oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe2O3, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control. Conclusions The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications.

  13. The permeability of the posterior blood ocular barrier after xenon photocoagulation: a study using fluorescein labelled dextrans.

    OpenAIRE

    McNaught, E I; Foulds, W S; Johnson, N. F.

    1981-01-01

    Xenon photocoagulation burns in the rabbit fundus were studied angiographically with fluorescein labelled dextrans of molecular weights in the range 3000 to 150 000. Recent photocoagulation burns showed dye leakage to all molecular weights used. Angiograms 2 days after burns had been produced showed leakage of dextrans of molecular weights up to and including 70 000 but no leakage of dextran of 150 000 molecular weight. At 7 days after photocoagulation healed burns remained permeable to dextr...

  14. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking.

    Science.gov (United States)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K; Holers, V Michael; Wu, LinPing; Moghimi, S Moein; Simberg, Dmitri

    2016-01-01

    While having tremendous potential as therapeutic and imaging tools, the clinical use of engineered nanoparticles has been associated with serious safety concerns. Activation of the complement cascade and the release of proinflammatory factors C3a and C5a may contribute to infusion-related reactions, whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry in inciting complement in human serum. Using complement inhibitors and measuring levels of fluid phase markers (sC5b-9, C5a, and Bb), we found that the majority of human complement activation by SPIO is through the alternative pathways (AP). SPIO prepared with high dextran/iron ratio showed some complement activation via calcium-sensitive pathways, but the AP was responsible for the bulk of complement activation and amplification. Activation via the AP required properdin, the positive regulator of the alternative C3bBb convertase. Modification of sugar alcohols of dextran with alkylating, acylating, or crosslinking agents did not overcome complement activation and C3 opsonization. These data demonstrate that human complement activation is independent of dextran modification of SPIO and suggest a crucial role of the AP in immune recognition of nano-assemblies in human serum.

  15. Apparatus for washing particulate material. [Removal of silicone oil from microspheres by trichloroethylene

    Science.gov (United States)

    Rivera, A.L.; Fowler, V.L.; Justice, G.V.

    1983-12-29

    Transport of nuclear fuel microspheres through a wash liquid is facilitated by feeding a slurry containing the microspheres into the wash liquid via a column having a vibrating tubular screen located under its lower end.

  16. In vitro growth factor release from injectable calcium phosphate cements containing gelatin microspheres.

    NARCIS (Netherlands)

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

    2009-01-01

    To improve the in vivo resorption of an injectable calcium phosphate cement (CPC) for bone tissue engineering purposes, in previous experiments macroporosity was introduced by the in situ degradation of incorporated gelatin microspheres. Gelatin microspheres are also suitable carriers for

  17. Rheology and bioactivity of high molecular weight dextrans synthesised by lactic acid bacteria.

    Science.gov (United States)

    Zarour, Kenza; Llamas, Mª Goretti; Prieto, Alicia; Rúas-Madiedo, Patricia; Dueñas, María Teresa; de Palencia, Pilar Fernández; Aznar, Rosa; Kihal, Mebrouk; López, Paloma

    2017-10-15

    Dextrans synthesised by three Leuconostoc mesenteroides strains, isolated from mammalian milks, were studied and compared with dextrans produced by Lc. mesenteroides and Lactobacillus sakei strains isolated from meat products. Size exclusion chromatography coupled with multiangle laser light scattering detection analysis demonstrated that the dextrans have molecular masses between 1.74×10 8 Da and 4.41×10 8 Da. Rheological analysis of aqueous solutions of the polymer revealed that all had a pseudoplastic behaviour under shear conditions and a random, and flexible, coil structure. The dextrans showed at shear zero a difference in viscosity, which increased as the concentration increased. Also, the purified dextrans were able to immunomodulate in vitro human macrophages, partially counteracting the inflammatory effect of Escherichia coli O111:B4 lipopolysaccharide. During prolonged incubation on a solid medium containing sucrose, dextran-producing bacteria showed two distinct phenotypes not related to the genus or species to which they belonged. Colonies of Lc. mesenteroides CM9 from milk and Lb. sakei MN1 from meat formed stable and compact mucoid colonies, whereas the colonies of the other three Leuconostoc strains became diffuse after 72h. This differential behaviour was also observed in the ability of the corresponding strains to bind to Caco-2 cells. Strains forming compact mucoid colonies showed a high level of adhesion when grown in the presence of glucose, which decreased in the presence of sucrose (the condition required for dextran synthesis). However no influence of the carbon source was detected for the adhesion ability of the other Lc. mesenteroides strains, which showed variable levels of binding to the enterocytes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Dextran: Influence of Molecular Weight in Antioxidant Properties and Immunomodulatory Potential

    Directory of Open Access Journals (Sweden)

    Vinicius C. Soeiro

    2016-08-01

    Full Text Available Dextrans (α-d-glucans extracted from Leuconostoc mesenteroides, with molecular weights (MW of 10 (D10, 40 (D40 and 147 (D147 kDa, were evaluated as antioxidant, anticoagulant and immunomodulatory drugs for the first time. None presented anticoagulant activity. As for the antioxidant and immunomodulatory tests, a specific test showed an increase in the dextran activity that was proportional to the increase in molecular weight. In a different assay, however, activity decreased or showed no correlation to the MW. As an example, the reducing power assay showed that D147 was twice as potent as other dextrans. On the other hand, all three samples showed similar activity (50% when it came to scavenging the OH radical, whereas only the D10 sample showed sharp activity (50% when it came to scavenging the superoxide ion. D40 was the single dextran that presented with immunomodulatory features since it stimulated the proliferation (~50% of murine macrophages (RAW 264.7 and decreased the release of nitric oxide (~40% by the cells, both in the absence and presence of lipopolysaccharides (LPS. In addition, D40 showed a greater scavenging activity (50% for the hydrogen peroxide, which caused it to also be the more potent dextran when it came to inhibiting lipid peroxidation (70%. These points toward dextrans with a 40 kDa weight as being ideal for antioxidant and immunomodulatory use. However, future studies with the D40 and other similarly 40 kDa dextrans are underway to confirm this hypothesis.

  19. Pulmonary permeability assessed by fluorescent-labeled dextran instilled intranasally into mice with LPS-induced acute lung injury.

    Directory of Open Access Journals (Sweden)

    Honglei Chen

    Full Text Available Several different methods have been used to assess pulmonary permeability in response to acute lung injury (ALI. However, these methods often involve complicated procedures and algorithms that are difficult to precisely control. The purpose of the current study is to establish a feasible method to evaluate alterations in lung permeability by instilling fluorescently labeled dextran (FITC-Dextran intranasally.For the mouse model of direct ALI, lipopolysaccharide (LPS was administered intranasally. FITC-Dextran was instilled intranasally one hour before the mice were euthanized. Plasma fluorescence intensities from the LPS group were significantly higher than in the control group. To determine the reliability and reproducibility of the procedure, we also measured the lung wet-to-dry weight ratio, the protein concentration of the bronchoalveolar lavage fluid, tight and adherens junction markers and pathological changes. Consistent results were observed when the LPS group was compared with the control group. Simultaneously, we found that the concentration of plasma FITC-Dextran was LPS dose-dependent. The concentration of plasma FITC-Dextran also increased with initial intranasal FITC-Dextran doses. Furthermore, increased fluorescence intensity of plasma FITC-Dextran was found in the intraperitoneally LPS-induced ALI model.In conclusion, the measurement of FITC-Dextran in plasma after intranasal instillation is a simple, reliable, and reproducible method to evaluate lung permeability alterations in vivo. The concentration of FITC-Dextran in the plasma may be useful as a potential peripheral biomarker of ALI in experimental clinical studies.

  20. Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications.

    Science.gov (United States)

    Yamamoto, Yohei; Okada, Daichi; Kushida, Soh; Ngara, Zakarias Seba; Oki, Osamu

    2017-06-02

    This paper describes three methods of preparing fluorescent microspheres comprising π-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, π-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (µ-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, µ-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

  1. The synthesis and photocatalytic activity of ZnSe microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao Huaqiang; Xiao Yujiang; Zhang Sichun, E-mail: hqcao@mail.tsinghua.edu.cn [Department of Chemistry, Tsinghua University, Beijing 100084 (China)

    2011-01-07

    This paper reports the synthesis of semiconductor ZnSe microspheres composed of nanoparticles via a solvothermal route between the organic molecule selenophene (C{sub 4}H{sub 4} Se) and ZnCl{sub 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 ({approx}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.

  2. Microsphere-based super-resolution scanning optical microscope.

    Science.gov (United States)

    Huszka, Gergely; Yang, Hui; Gijs, Martin A M

    2017-06-26

    High-refractive index dielectric microspheres positioned within the field of view of a microscope objective in a dielectric medium can focus the light into a so-called photonic nanojet. A sample placed in such nanojet can be imaged by the objective with super-resolution, i.e. with a resolution beyond the classical diffraction limit. However, when imaging nanostructures on a substrate, the propagation distance of a light wave in the dielectric medium in between the substrate and the microsphere must be small enough to reveal the sample's nanometric features. Therefore, only the central part of an image obtained through a microsphere shows super-resolution details, which are typically ∼100 nm using white light (peak at λ = 600 nm). We have performed finite element simulations of the role of this critical distance in the super-resolution effect. Super-resolution imaging of a sample placed beneath the microsphere is only possible within a very restricted central area of ∼10 μm2, where the separation distance between the substrate and the microsphere surface is very small (∼1 μm). To generate super-resolution images over larger areas of the sample, we have fixed a microsphere on a frame attached to the microscope objective, which is automatically scanned over the sample in a step-by-step fashion. This generates a set of image tiles, which are subsequently stitched into a single super-resolution image (with resolution of λ/4-λ/5) of a sample area of up to ∼104 μm2. Scanning a standard optical microscope objective with microsphere therefore enables super-resolution microscopy over the complete field-of-view of the objective.

  3. 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

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

    Science.gov (United States)

    2011-03-21

    the PEI-coated PLGA microspheres labeled with FITC were imaged on a Leica 6000 inverted fluorescence microscope (Leica microsystems, Bannockburn, IL...microspheres and dried overnight at room temperature. This method is illustrated in Fig. 1. Using a Leica 6000 inverted fluorescence microscope , HAp...microspheres. (B) Fluorescence microscope image of PEI-coated PLGA microspheres. Fig. 4. (A) Zeta potential profile of (a) sintered HAp, (b) control PLGA

  5. Effects of the Gram stain on microspheres from thermal polyamino acids.

    Science.gov (United States)

    FOX, S W; YUYAMA, S

    1963-02-01

    Fox, Sidney W. (The Florida State University, Tallahassee) and Shuhei Yuyama. Effects of the Gram stain on microspheres from thermal polyamino acids. J. Bacteriol. 85:279-283. 1963.-Microspheres produced from acid proteinoid accept the Gram stain. The stain is negative, but microspheres produced from mixtures containing a sufficient proportion of lysine proteinoid stain positive. Microspheres produced from mixtures containing the appropriate proportions contain individuals which stain positive and others which stain negative.

  6. EFFECTS OF THE GRAM STAIN ON MICROSPHERES FROM THERMAL POLYAMINO ACIDS1

    Science.gov (United States)

    Fox, Sidney W.; Yuyama, Shuhei

    1963-01-01

    Fox, Sidney W. (The Florida State University, Tallahassee) and Shuhei Yuyama. Effects of the Gram stain on microspheres from thermal polyamino acids. J. Bacteriol. 85:279–283. 1963.—Microspheres produced from acid proteinoid accept the Gram stain. The stain is negative, but microspheres produced from mixtures containing a sufficient proportion of lysine proteinoid stain positive. Microspheres produced from mixtures containing the appropriate proportions contain individuals which stain positive and others which stain negative. Images PMID:13959050

  7. PLGA microsphere/calcium phosphate cement composites for tissue engineering: in vitro release and degradation characteristics.

    NARCIS (Netherlands)

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

    2008-01-01

    Bone cements with biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres have already been proven to provide a macroporous calcium phosphate cement (CPC) during in situ microsphere degradation. Furthermore, in vitro/in vivo release studies with these PLGA microsphere/CPC composites

  8. Formulation and in vitro Evaluation of Eudragit® Microspheres of ...

    African Journals Online (AJOL)

    Methods: Microspheres were prepared by solvent evaporation method using an acetone / liquid paraffin system. Magnesium stearate was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeritic properties and drug loading, ...

  9. Ulex europaeus 1 lectin targets microspheres to mouse Peyer's patch M-cells in vivo.

    Science.gov (United States)

    Foster, N; Clark, M A; Jepson, M A; Hirst, B H

    1998-03-01

    The interaction of latex microspheres with mouse Peyer's patch membranous M-cells was studied in a mouse gut loop model after the microspheres were coated with a variety of agents. Carboxylated microspheres (diameter 0.5 micron) were covalently coated with lectins Ulex europaeus 1, Concanavalin A, Euonymus europaeus and Bandeiraea simplicifolia 1 isolectin-B4, human immunoglobulin A or bovine serum albumin. Of the treatments examined, only Ulex europaeus (UEA1) resulted in significant selective binding of microspheres to M-cells. UEA1-coated microspheres bound to M-cells at a level 100-fold greater than BSA-coated microspheres, but binding to enterocytes was unaffected. Incubation of UEA1-coated microspheres with alpha-L-fucose reduced M-cell binding to a level comparable with BSA-coated microspheres. This indicated that targeting by UEA1 was via a carbohydrate receptor on the M-cell surface. Adherence of UEA1-coated microspheres to M-cells occurred within 10 min of inoculation into mouse gut loops and UEA1-coated microspheres were transported to 10 microns below the apical surface of M-cells within 60 min of inoculation. UEA1-coated microspheres also targeted mouse Peyer's patch M-cells after intragastric administration. These results demonstrated that altering the surface chemistry of carboxylated polystyrene microspheres increased M-cell targeting, suggesting a strategy to enhance delivery of vaccine antigens to the mucosal immune system.

  10. In situ growth of copper nanocrystals from carbonaceous microspheres with electrochemical glucose sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaoliang; Yan, Zhengguang, E-mail: yanzg2004@gmail.com; Han, Xiaodong, E-mail: xdhan@bjut.edu.cn

    2014-02-01

    Graphical abstract: In situ growth of copper nanoparticles from hydrothermal copper-containing carbonaceous microspheres was induced by annealing or electron beam irradiation. Obtained micro-nano carbon/copper composite microspheres show electrochemical glucose sensing properties. - Highlights: • We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. • By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. • By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500 nm. • The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. - Abstract: In situ growth of copper nanocrystals from carbon/copper microspheres was observed in a well-controlled annealing or an electron beam irradiation process. Carbonaceous microspheres containing copper species with a smooth appearance were yielded by a hydrothermal synthesis using copper nitrate and ascorbic acid as reactants. When annealing the carbonaceous microspheres under inert atmosphere, copper nanoparticles were formed on carbon microspheres and the copper particle sizes can be increased to a range of 50–500 nm by altering the heating temperature. Similarly, in situ formation of copper nanocrystals from these carbonaceous microspheres was observed on the hydrothermal product carbonaceous microspheres with electron beam irradiation in a vacuum transmission electron microscopy chamber. The carbon/copper composite microspheres obtained through annealing were used to modify a glassy carbon electrode and tested as an electrochemical glucose sensor.

  11. Iron dextran treatment does not induce serum protein carbonyls in the newborn pig.

    Science.gov (United States)

    Caperna, T J; Shannon, A E; Blomberg, L A; Garrett, W M; Ramsay, T G

    2012-01-01

    Oxidation of serum proteins can lead to carbonyl formation that alters their function and is often associated with stress-related diseases. As it is recommended that all pigs reared in modern production facilities be given supplemental iron at birth to prevent anemia, and metals can catalyze the carbonylation of proteins, the primary objective of this study was to determine whether standard iron dextran treatment was associated with enhanced serum protein oxidation in newborn piglets. Piglets were treated with 100 mg of iron dextran intramuscularly either on the day of birth, or on the third day after birth. Blood samples were collected from piglets 48 or 96 h after treatment and serum was harvested. For quantification, serum protein carbonyls were converted to hydrazones with dinitrophenyl hydrazine and analyzed spectrophotometrically. To identify and determine relative distribution of carbonylated proteins, serum protein carbonyls were derivatized with biotin hydrazide, separated by two-dimensional polyacrylamide gel electrophoresis, stained with avidin-fluorescein and identified by mass spectrometry. The standard iron dextran treatment was associated with no increase in total oxidized proteins if given either on the first or third day of life. In addition, with a few noted exceptions, the overall distribution and identification of oxidized proteins were similar between control and iron dextran-treated pigs. These results indicate that while iron dextran treatment is associated with a marked increase in circulating iron, it does not appear to specifically induce the oxidation of serum proteins.

  12. Metallization and biopatterning on ultra-flexible substrates via dextran sacrificial layers.

    Science.gov (United States)

    Tseng, Peter; Pushkarsky, Ivan; Di Carlo, Dino

    2014-01-01

    Micro-patterning tools adopted from the semiconductor industry have mostly been optimized to pattern features onto rigid silicon and glass substrates, however, recently the need to pattern on soft substrates has been identified in simulating cellular environments or developing flexible biosensors. We present a simple method of introducing a variety of patterned materials and structures into ultra-flexible polydimethylsiloxane (PDMS) layers (elastic moduli down to 3 kPa) utilizing water-soluble dextran sacrificial thin films. Dextran films provided a stable template for photolithography, metal deposition, particle adsorption, and protein stamping. These materials and structures (including dextran itself) were then readily transferrable to an elastomer surface following PDMS (10 to 70∶1 base to crosslinker ratios) curing over the patterned dextran layer and after sacrificial etch of the dextran in water. We demonstrate that this simple and straightforward approach can controllably manipulate surface wetting and protein adsorption characteristics of PDMS, covalently link protein patterns for stable cell patterning, generate composite structures of epoxy or particles for study of cell mechanical response, and stably integrate certain metals with use of vinyl molecular adhesives. This method is compatible over the complete moduli range of PDMS, and potentially generalizable over a host of additional micro- and nano-structures and materials.

  13. Metallization and biopatterning on ultra-flexible substrates via dextran sacrificial layers.

    Directory of Open Access Journals (Sweden)

    Peter Tseng

    Full Text Available Micro-patterning tools adopted from the semiconductor industry have mostly been optimized to pattern features onto rigid silicon and glass substrates, however, recently the need to pattern on soft substrates has been identified in simulating cellular environments or developing flexible biosensors. We present a simple method of introducing a variety of patterned materials and structures into ultra-flexible polydimethylsiloxane (PDMS layers (elastic moduli down to 3 kPa utilizing water-soluble dextran sacrificial thin films. Dextran films provided a stable template for photolithography, metal deposition, particle adsorption, and protein stamping. These materials and structures (including dextran itself were then readily transferrable to an elastomer surface following PDMS (10 to 70∶1 base to crosslinker ratios curing over the patterned dextran layer and after sacrificial etch of the dextran in water. We demonstrate that this simple and straightforward approach can controllably manipulate surface wetting and protein adsorption characteristics of PDMS, covalently link protein patterns for stable cell patterning, generate composite structures of epoxy or particles for study of cell mechanical response, and stably integrate certain metals with use of vinyl molecular adhesives. This method is compatible over the complete moduli range of PDMS, and potentially generalizable over a host of additional micro- and nano-structures and materials.

  14. Dextran synthesized by Leuconostoc mesenteroides BD1710 in tomato juice supplemented with sucrose.

    Science.gov (United States)

    Han, Jin; Hang, Feng; Guo, Benheng; Liu, Zhenmin; You, Chunpin; Wu, Zhengjun

    2014-11-04

    The characteristics of the growth of Leuconostoc mesenteroides BD1710 and the synthesis of dextran in tomato juice supplemented with 15% sucrose were assayed. L. mesenteroides BD1710 could synthesize approximately 32 g L(-1) dextran in the tomato-juice-sucrose medium when cultured at 28 °C for 48 h, which was on the same level as the dextran yield in a chemically defined medium. The viscosity of the cultured tomato-juice-sucrose medium with various dextran contents was also measured. The results of the monosaccharide composition, molecular-weight distribution, Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance spectra (NMR) showed that the polysaccharide synthesized by L. mesenteroides BD1710 in the tomato-juice-sucrose medium was dextran with a peak molecular weight of 6.35 × 10(5)Da, a linear backbone composed of consecutive α-(1 → 6)-linked d-glucopyranosyl units and approximately 6% α-(1 → 3) branches. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Production of dextran from sucrose by a newly isolated strain of Leuconostoc mesenteroides (PCSIR-3) with reference to L. mesenteroides NRRL B-512F.

    Science.gov (United States)

    Ul-Qader, S A; Iqbal, L; Rizvi, H A; Zuberi, R

    2001-10-01

    A newly isolated strain of Leuconostoc mesenteroides (PCSIR-3) produced a different dextran compared with that of L. mesenteroides NRRL B-512F. Different media compositions used for dextran production showed that media containing CaCl(2) produced dextran in higher quantities compared with other media. The viscosity of the dextran produced in different media varied in nature. Dextran from media 1 and 2 was of higher molecular mass compared with that from media 3, 4 and 5. Dextran production is also effected by the sucrose concentration in the media. The higher the initial concentration of sucrose, the higher is the yield of dextran produced per unit volume; however, the percentage conversion of sucrose into dextran decreases. A continuous drop in pH was associated with growth and dextran production. The yield of dextran increases during the growth phase and maximum yield was obtained at the end of the exponential phase. Dextran produced by L. mesenteroides PCSIR-3 is quite different from the dextran produced by NRRL B-512F. Maximum dextran production from L. mesenteroides PCSIR-3 occurs in 18 h compared with 12 h for NRRL B-512F.

  16. Preparation of chitosan-TPP microspheres as resveratrol carriers.

    Science.gov (United States)

    Cho, Ah Ra; Chun, Yong Gi; Kim, Bum Keun; Park, Dong June

    2014-04-01

    Resveratrol (3,4',5-trihydroxy-trans-stilbene)-loaded chitosan-sodium tripolyphosphate (TPP) microspheres using high (310 to 375 kDa) and medium (190 to 310 kDa) molecular weight chitosan and TPP in varying concentrations were produced to improve resveratrol bioavailability. A 450 μm nozzle encapsulator was used to produce the microspheres. The mean microsphere particle size was between 160 and 206 μm, and exhibited a narrower size distribution as the TPP solution concentration increased. The encapsulation efficiency increased from 94% to 99% with a decrease in chitosan concentration from 1% to 0.5% and a decrease in crystallinity of the microspheres. FTIR data showed a polyelectrolyte interaction between chitosan and TPP. X-ray diffraction patterns were matched up with DSC and FTIR, which shows decrease of crystallinity and enhancement of hydrogen bonding with TPP concentration. An increase in the concentration of TPP solution from 1% to 3% led to a lower initial burst of resveratrol release. These results suggest that chitosan-TPP microspheres could be used as a potential delivery system to control the release of resveratrol. © 2014 Institute of Food Technologists®

  17. Effect of dextran and dextran sulfate on the structural and rheological properties of model acid milk gels.

    Science.gov (United States)

    Pachekrepapol, U; Horne, D S; Lucey, J A

    2015-05-01

    Various types of polysaccharides are widely used in cultured dairy products. However, the interaction mechanisms, between milk proteins and these polysaccharides, are not entirely clear. To explore the interactions between uncharged and charged polysaccharides and the caseins, we used a model acid-milk-gel system, which allowed acidification to occur separately from gelation. The effect of adding uncharged dextran (DX; molecular weight ~2.0×10(6) Da) and negatively charged dextran sulfate (DS; molecular weight ~1.4×10(6) Da) to model acid milk gels was studied. Two concentrations (0.075 and 0.5%, wt/wt) of DX or DS were added to cold milk (~0°C) that had been acidified to pH values 4.4, 4.6, 4.8, or 4.9. Acidified milks containing DX or DS were then quiescently heated at the rate of 0.5°C/min to 30°C, which induced gelation, and gels were then held at 30°C for 17 h to facilitate gel development. Dynamic small-amplitude-oscillation rheology and large-deformation (shear) tests were performed. Microstructure of gels was examined by fluorescence microscopy. Gels made with a high concentration of DX gelled at a lower temperature, but after 17 h at 30°C, these gels exhibited lower storage moduli and lower yield-stress values. At pH 4.8 or 4.9 (pH values greater than the isoelectric point of caseins), addition of 0.5% DS to acidified milk resulted in lower gelation temperature. At pH 4.4 (pH values less than the isoelectric point of caseins), addition of 0.5% DS to acidified milk resulted in gels with very high stiffness values. Gels made at pH 4.8 or 4.9 with both concentrations of DS had much lower stiffness and yield-stress values than control gels. Microstructural analysis indicated that gels made at pH 4.4 with the addition of 0.5% DX exhibited large protein strands and pores, whereas gels made with 0.075% DX or the control gels had a finer protein matrix. At higher pH values (>4.4), gels made with 0.5% DX had a finer structure. At all pH values, gels made

  18. Synthesis of polymer/zirconium hydroxide core-shell microspheres and the hollow porous zirconium oxide microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dianbin; Yan, Enwei; Yu, Jinhui; Zhang, Wei; Liu, Bin [Key Laboratory of Functional Polymer Materials, the Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin 300071 (China); Yang, Xinlin, E-mail: xlyang88@nankai.edu.cn [Key Laboratory of Functional Polymer Materials, the Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin 300071 (China)

    2012-10-15

    Narrow-disperse poly(N,N Prime -methylenebisacryamide-co-methacrylic acid)/zirconium hydroxide (P(MBA-co-MAA)/Zr(OH){sub 4}) core-shell composite microspheres were synthesized by the controlled sol-gel hydrolysis of inorganic zirconium n-butoxide (Zr(OBu){sub 4}) precursor in ethanol and acetonitrile mixed solvent with P(MBA-co-MAA) microspheres as templates. The thickness of the outer inorganic Zr(OH){sub 4} shell-layer was well-controlled via altering the mass ratio of Zr(OBu){sub 4} to P(MBA-co-MAA) core particles as well as the water used for the hydrolysis. The corresponding hollow porous zirconium oxide (ZrO{sub 2}) microspheres were obtained after the selective removal of P(MBA-co-MAA) core via the calcination of P(MBA-co-MAA)/Zr(OH){sub 4} core-shell microspheres under 550 Degree-Sign C for 4 h in air. The structure and morphology of the resultant core-shell microspheres and the hollow porous ZrO{sub 2} microspheres were characterized by transmission electron microscopy (TEM), STEM together with EDX spectrum, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, micromeritic analyzer, and thermogravimetric (TGA) analysis. -- Graphical abstract: Monodisperse P(MBA-co-MAA)/(ZrOH){sub 4} core-shell microspheres with amorphous zirconium hydroxide shell-layer were prepared by the controlled hydrolysis of Zr(OBu){sub 4} in acetonitrile/ethanol (4/1, V/V) mixed solvent. The mechanism of the encapsulation of zirconium hydroxide shell-layer over P(MBA-co-MAA) templates were performed via the efficient hydrogen-bonding interaction between the carboxylic acid groups as well as the amide groups on the surface of P(MBA-co-MAA) templates and the hydroxyl groups of the zirconium hydroxide molecules during the controlled hydrolysis. Highlights: Black-Right-Pointing-Pointer Synthesis of P(MBA-co-MAA)/Zr(OH){sub 4} core-shell composite microspheres. Black-Right-Pointing-Pointer Controlled thickness of Zr(OH){sub 4} shell-layer via altering loadings

  19. THE UPTAKE OF IRON IN RABBIT SYNOVIAL TISSUE FOLLOWING INTRA-ARTICULAR INJECTION OF IRON DEXTRAN

    Science.gov (United States)

    Ball, J.; Chapman, J. A.; Muirden, K. D.

    1964-01-01

    Iron dextran (molecular weight 7,000) diffuses rapidly from the joint cavity through the synovium, along lymphatics and extracellular tissue spaces; articular cartilage is impermeable to iron dextran. There is also rapid cellular uptake by synovial lining cells, particularly of the vacuolar type; endoplasmic reticulum-containing lining cells rarely take up iron dextran. Cellular uptake is probably effected by pseudopodial folds projecting from the cell surface and enclosing extracellular material. Cells containing iron may degenerate and be ingested by phagocytes, and this may account for the concentration of iron in a smaller proportion of cells on or below the synovial surface in the later stages. At 6 to 18 hours after injection there is a mild inflammatory reaction and some synovial proliferation; from this stage onwards intracellular iron occurs in the form of haemosiderin. Granules of haemosiderin are present in the synovium 3 months after injection and possibly longer. PMID:14203385

  20. Coacervate-like microspheres from lysine-rich proteinoid

    Science.gov (United States)

    Rohlfing, D. L.

    1975-01-01

    Microspheres form isothermally from lysine-rich proteinoid when the ionic strength of the solution is increased with NaCl or other salts. Studies with different monovalent anions and with polymers of different amino acid composition indicate that charge neutralization and hydrophobic bonding contribute to microsphere formation. The particles also form in sea water, especially if heated or made slightly alkaline. The microspheres differ from those made from acidic proteinoid but resemble coacervate droplets in some ways (isothermal formation, limited stability, stabilization by quinone, uptake of dyes). Because the constituent lysine-rich proteinoid is of simulated prebiotic origin, the study is interpreted to add emphasis to and suggest an evolutionary continuity for coacervation phenomena.

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

    Directory of Open Access Journals (Sweden)

    Lin C.

    2011-01-01

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

  2. Strain sensor based on hollow microsphere Fabry-Perot cavity

    Science.gov (United States)

    Monteiro, Catarina S.; Silva, Susana O.; Frazão, Orlando

    2017-08-01

    Fusion splicing technique was explored for the fabrication of two sensing structures based on hollow microsphere Fabry- Perot cavity. The first sensor proposed was fabricated with a hollow microsphere tip, working as a probe sensor. This structure was studied for lateral load pressure, yielding a 1.56 +/- 0.01 nm/N sensitivity. The second sensing structure relied on an in-line hollow microsphere, which allowed the detection of lateral load, with a sensitivity of 2.62 +/- 0.02 nm/N. Furthermore, the proposed structure enabled strain sensing, with a sensitivity of 4.66 +/- 0.03 pm/μɛ. The two sensing structures were subjected to temperature, presenting low thermal cross-sensitivity.

  3. Floating microspheres: to prolong the gastric retention time in stomach.

    Science.gov (United States)

    Bhadouriya, Priyanka; Kumar, Manish; Pathak, Kamla

    2012-05-01

    A gastroretentive drug delivery system with prolong retention time in the stomach have great practical importance for drugs with an absorption window in the upper small intestine. Floating drug delivery system are expected to remain buoyant in the gastric content for prolong duration of time thus enhance the bioavailability of drugs. There are several gastroretentive drug delivery systems, which are floating microspheres, granules, tablets, powder, pills, laminated films and capsules. Floating microspheres are gaining special attention because of their wide applicability in the targeting of drug to stomach. Floating microspheres have several advantages, that they remain buoyant in the stomach and distributed uniformly to avoid the vagaries of gastric emptying and release the drug for prolong period of time.

  4. 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)

  5. [Preparation and evaluation of sustained-release microsphere of Sanguis Draconis in vitro].

    Science.gov (United States)

    Ding, Li-Yu; Xia, Peng-Fei; Yang, Cai-Qin; Lin, Yu-Long; Wang, Jing

    2007-03-01

    To prepare sustained-release microsphere containing extract of Sanguis Draconis and to measure its dissolution in vitro. Sustained-release microsphere was prepared with polylactic acid (PLA) as carriers using the oil-in-water (O/W) emulsion solvent evaporation method. The powder particle's characteristics of sustainded-release microsphere were evaluated comprehensively, and its dissolution characteristics in vitro were studied. The microsphere was round and its surface was smooth, drug-loading rate was 21.97% and the entrapment rate was 55.76%, the accumulative release percentage was 76. 71% in 16 hours. The sustained release effect of Sanguis Draconis microspheres was formed with potentially wide applications.

  6. Morphological alterations of exogenous surfactant inhibited by meconium can be prevented by dextran

    Directory of Open Access Journals (Sweden)

    Stichtenoth Guido

    2006-06-01

    Full Text Available Abstract Background Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM and stereology allows the differentiation of active (large aggregates = LA and inactive (small aggregates = SA subtypes. Methods To determine the in vitro effects of meconium and dextran addition on the morphology of a modified porcine natural surfactant (Curosurf, Curosurf samples were either incubated alone or together with meconium or with meconium and dextran, fixed and processed for TEM. Volume fractions of surfactant subtypes [lamellar body-like forms (LBL, multilamellar vesicles (MV, unilamellar vesicles (UV] were determined stereologically. Results All preparations contained LBL and MV (corresponding to LA as well as UV (corresponding to SA. The volume fraction of UV increased with addition of meconium and decreased with further addition of dextran. Correspondingly, the UV/(LBL+MV ratio (resembling the SA/LA ratio increased when meconium was added and decreased when dextran was added to the surfactant-meconium mixture. Conclusion Meconium causes alterations in the ultrastructural composition of Curosurf that can be visualized and analyzed by TEM and stereology. These alterations resemble an increase in the SA/LA ratio and are paralleled by an increase in minimum surface tension. Dextran prevents these effects and may therefore be a useful additive to exogenous surfactant preparations to preserve their structural and functional integrity, thereby improving their resistance to inactivation.

  7. Effect of microstructure on population growth parameters of Escherichia coli in gelatin-dextran systems.

    Science.gov (United States)

    Boons, Kathleen; Noriega, Estefanía; Van den Broeck, Rob; David, Charlotte C; Hofkens, Johan; Van Impe, Jan F

    2014-09-01

    Current literature acknowledges the effect of food structure on bacterial dynamics. Most studies introduce this "structure" factor using a single gelling agent, resulting in a homogeneous environment, whereas in practice most food products are heterogeneous. Therefore, this study focuses on heterogeneous protein-polysaccharide mixtures, based on gelatin and dextran. These mixtures show phase separation, leading to a range of heterogeneous microstructures by adjusting relative concentrations of both gelling agents. Based on confocal microscope observations, the growth of Escherichia coli in gelatin-dextran systems was observed to occur in the dextran phase. To find a relation between microscopic and population behavior, growth experiments were performed in binary and singular gelatin-dextran systems and culture broth at 23.5°C, with or without adding 2.9% (wt/vol) NaCl. The Baranyi and Roberts growth model was fitted to the experimental data and parameter estimates were statistically compared. For salted binary mixtures, a decrease in the population maximum cell density was observed with increasing gelatin concentration. In this series, for one type of microstructure, i.e., a gelatin matrix phase with a disperse dextran phase, the maximum cell density decreased with decreasing percentage of dextran phase. However, this relation no longer held when other types of microstructure were observed. Compared to singular systems, adding a second gelling agent in the presence of NaCl had an effect on population lag phases and maximum cell densities. For unsalted media, the growth parameters of singular and binary mixtures were comparable. Introducing this information into mathematical models leads to more reliable growth predictions and enhanced food safety. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  8. Hypertonic Saline Dextran Ameliorates Organ Damage in Beagle Hemorrhagic Shock.

    Directory of Open Access Journals (Sweden)

    Jing-xiang Zhao

    Full Text Available The goal of this study was to investigate the effect of hypertonic saline with 6% Dextran-70 (HSD resuscitation on organ damage and the resuscitation efficiency of the combination of HSD and lactated ringers (LR in a model of hemorrhage shock in dogs.Beagles were bled to hold their mean arterial pressure (MAP at 50 ± 5 mmHg for 1 h. After hemorrhage, beagles were divided into three groups (n = 7 to receive pre-hospital resuscitation for 1 h (R1: HSD (4 ml/kg, LR (40 ml/kg, and HSD+LR (a combination of 4 ml/kg HSD and 40 ml/kg LR. Next, LR was transfused into all groups as in-hospital resuscitation (R2. After two hours of observation (R3, autologous blood was transfused. Hemodynamic responses and systemic oxygenation were measured at predetermined phases. Three days after resuscitation, the animals were sacrificed and tissues including kidney, lung, liver and intestinal were obtained for pathological analysis.Although the initial resuscitation with HSD was shown to be faster than LR with regard to an ascending MAP, the HSD group showed a similar hemodynamic performance compared to the LR group throughout the experiment. Compared with the LR group, the systemic oxygenation performance in the HSD group was similar but showed a lower venous-to-arterial CO2 gradient (Pv-aCO2 at R3 (p < 0.05. Additionally, the histology score of the kidneys, lungs and liver were significantly lower in the HSD group than in the LR group (p < 0.05. The HSD+LR group showed a superior hemodynamic response but higher extravascular lung water (EVLW and lower arterial oxygen tension (PaO2 than the other groups (p < 0.05. The HSD+LR group showed a marginally improved systemic oxygenation performance and lower histology score than other groups.Resuscitation after hemorrhagic shock with a bolus of HSD showed a similar hemodynamic response compared with LR at ten times the volume of HSD, but HSD showed superior efficacy in organ protection. Our findings suggest that

  9. Polysaccharide-based aerogel microspheres for oral drug delivery.

    Science.gov (United States)

    García-González, C A; Jin, M; Gerth, J; Alvarez-Lorenzo, C; Smirnova, I

    2015-03-06

    Polysaccharide-based aerogels in the form of microspheres were investigated as carriers of poorly water soluble drugs for oral administration. These bio-based carriers may combine the biocompatibility of polysaccharides and the enhanced drug loading capacity of dry aerogels. Aerogel microspheres from starch, pectin and alginate were loaded with ketoprofen (anti-inflammatory drug) and benzoic acid (used in the management of urea cycle disorders) via supercritical CO2-assisted adsorption. Amount of drug loaded depended on the aerogel matrix structure and composition and reached values up to 1.0×10(-3) and 1.7×10(-3) g/m(2) for ketoprofen and benzoic acid in starch microspheres. After impregnation, drugs were in the amorphous state in the aerogel microspheres. Release behavior was evaluated in different pH media (pH 1.2 and 6.8). Controlled drug release from pectin and alginate aerogel microspheres fitted Gallagher-Corrigan release model (R(2)>0.99 in both cases), with different relative contribution of erosion and diffusion mechanisms depending on the matrix composition. Release from starch aerogel microspheres was driven by dissolution, fitting the first-order kinetics due to the rigid starch aerogel structure, and showed different release rate constant (k1) depending on the drug (0.075 and 0.160 min(-1) for ketoprofen and benzoic acid, respectively). Overall, the results point out the possibilities of tuning drug loading and release by carefully choosing the polysaccharide used to prepare the aerogels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Synthesis and Characterization of Graft Copolymer of Dextran and 2-Acrylamido-2-methylpropane Sulphonic Acid

    Directory of Open Access Journals (Sweden)

    Venkanna Azmeera

    2012-01-01

    Full Text Available A novel biodegradable graft copolymer of dextran (Dx and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS was synthesized by grafting poly-AMPS chains onto dextran backbone by free radical polymerization using ceric ammonium nitrate (CAN as an initiator. Different amounts of AMPS were used to synthesize four different grades of graft copolymers with different side chain lengths. These grafted polymers were characterized by elemental analysis, FTIR, 1HNMR, rheological technique, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and X-ray diffractometry (XRD. They exhibited efficient flocculation performance in kaolin suspension.

  11. THE DETERMINATION OF SERUM IRON AFTER THE INTRAVENOUS INJECTION OF IRON-DEXTRAN

    Science.gov (United States)

    Webster, D.

    1960-01-01

    A rapid technique for the determination of iron in serum, after the intravenous injection of iron-dextran, is presented. Dithionite is used for the reduction of ferric to ferrous iron. The use of a detergent solution enables protein precipitation to be omitted. The iron reagent, 4: 7-diphenyl-1: 10-phenanthroline, and its ferrous complex are both soluble in the dilute detergent solution. Lipaemic serum can be used without affecting the results. The recovery of added ferric iron, as iron-dextran, is quantitative. PMID:13843331

  12. Camomile autofermentation in polyethylene glycol/dextran two-phase system

    Directory of Open Access Journals (Sweden)

    Đaković Sanja D.

    2008-01-01

    Full Text Available The objective of this study was the investigation of the extractive bioconversion of apigenin-7-O-β-glucoside in camomile ligulate flowers into apigenin by autofermentation in polyethylene glycol 6000/dextran 200000 two-phase system. In 22.5% polyethylene glycol/14% dextran aqueous two-phase system the obtained yield of apigenin in the top phase was 96.5%. In the presence of plant material that partiotioned to the interphase, the yield of apigenin in the top phase was 3.5 times higher in comparison to the model system.

  13. An efficiently sustainable dextran-based flocculant: Synthesis, characterization and flocculation.

    Science.gov (United States)

    Li, Ruo-Han; Zhang, Hong-Bin; Hu, Xue-Qin; Gan, Wei-Wei; Li, Qiu-Ping

    2016-09-01

    Polysaccharide-modified flocculant is a notable material in the field of wastewater treatment. Synthesis of biopolysaccharide derivatives as eco-friendly flocculants is remarkably desired for environmental protection. This work presents an efficient flocculant synthesized through copolymerization of acrylamide, sodium acrylate (AS), and dextran. Physicochemical properties of the flocculant were evaluated. Process parameters of coal-washing wastewater flocculation were tested using Response Surface Method. The application of graft polymers exhibited efficient flocculation performance at low level of flocculant dosage in alkalescent environment. The improved dextran contributes to handle industrial effluent and sanitary sewage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. [Effect of dextran of 250.000 molecular weight on experimental cholesterin-sclerosis in rabbits].

    Science.gov (United States)

    Ferenc, S; Arpád, H; Gábor, L

    1976-07-01

    Effect of dextran of 250000 molecular weight on experimental cholesterin-sclerosis of rabbits was studied. Doses of 120 (mg/week) kg and 1200 (mg/week) kg administered during 12 weeks have resulted a protective effect. When doses of 1200 (mg/week) kg have been administered--in the aortic adventitia intensive cellular reaction, no hitherto described was revealed, which was considered to be a sing of the exhaustion of RES. This publication authors regard as a preliminary one. To clear whether the cellular reaction observed is a dextran-specific or macro-moleculespecific one further investigations are needed.

  15. Protein quantification in the presence of poly(ethylene glycol) and dextran using the Bradford method.

    Science.gov (United States)

    Barbosa, Helder; Slater, Nigel K H; Marcos, João C

    2009-12-01

    Some experimental methodologies require the quantification of protein in the presence of polymers like poly(ethylene glycol) (PEG) and dextran (DEX). In the aqueous two-phase system (ATPS) extraction of biomolecules, the interference of these phase-forming polymers on the Bradford quantification assay is commonly recognized. However, how these polymers interfere has not been reported hitherto. In this study we show that while dextran concentrations of 20% (w/w) can be used without error, loss of accuracy occurs for solutions with PEG concentrations >10% (w/w). Above this value a substantial decrease on the assay sensitivity is observed.

  16. Novel dextran derivatives with unconventional structure formed in an efficient one-pot reaction.

    Science.gov (United States)

    Hotzel, Konrad; Heinze, Thomas

    2016-11-03

    An efficient one-pot synthesis of new dextran derivatives is described. The functional groups of β-alanine, i.e., the carboxyl- and amine group, are converted independently in one-step by iminium chloride to form products with a single substituent. The dextran N-[(dimethylamino)methylene]-β-alanine ester is formed selectively. The structure of the resulting polymers is unambiguously determined by means of NMR- and FTIR-spectroscopy and elemental analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Pterins as sensors of response to the application of Fe3+ -dextran in piglets.

    Science.gov (United States)

    Smutna, Miriam; Svoboda, Martin; Breinekova, Klara

    2010-01-01

    The aim of the presented study was to assess the effect of a single administration of Fe(3+)-dextran on immune cell counts and pterin biomolecule production as novel sensors of the piglets' immune system activation, and to determine concentrations of cortisol, a traditional hormonal biosensor of the stress response. Pterins (neopterin and biopterin) in the piglets' blood serum were analyzed by separation using reversed-phase HPLC. A single dose of Fe(3+)-dextran produced a special stress situation in the piglets' organism which manifested itself by an increased production of neopterin (p livestock animals.

  18. Preparation of poly (L-lactic acid) microspheres by droplet-freezing process

    Energy Technology Data Exchange (ETDEWEB)

    Mao Yi [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China); Dong Yinsheng, E-mail: dongys@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China); Lin Pinghua [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Huazhong University of Science and Technology, Wuhan 430074 (China); Chu Chenglin; Sheng Xiaobo; Guo Chao [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China)

    2011-01-01

    A recently developed process of microsphere preparation, named droplet-freezing process is introduced in this paper. The PLLA microspheres were fabricated by the droplet-freezing process, the diameter and porosity of the microspheres were measured, and the micro-morphologies of the microspheres were characterized by scanning electron microscopy (SEM). The formation process of microspheres was achieved by two steps: first, after droplets dropped off the delivery tube, they became approximately spherical in the air under the effect of the surface tension; second, droplets dropped into liquid condensate and maintained the spherical shape, and were frozen during the free settling process. Experimental results indicated that the microspheres fabricated by the droplet-freezing process have uniform diameters and the diameter can be controlled properly, along with the increase of the PLLA concentration, the size of microspheres increases, but the porosity of the microspheres decreases. The microspheres with high porosity can be obtained with a low concentration of the PLLA solution. SEM analysis revealed that the surfaces and interiors of the microsphere contain plentiful and interconnected micro pores. The microspheres are hopeful to be applied in bone tissue engineering.

  19. Technical aspects of radioembolization with 90Y microspheres.

    Science.gov (United States)

    Salem, Riad; Lewandowski, Robert J; Sato, Kent T; Atassi, Bassel; Ryu, Robert K; Ibrahim, Saad; Nemcek, Albert A; Omary, Reed A; Madoff, David C; Murthy, Ravi

    2007-03-01

    Embolotherapy with radioactive microspheres, radioembolization, is gaining clinical acceptance as a therapeutic option for patients with liver malignancies. Knowledge of the anatomic variants in the mesenteric system is critical to safely administer this therapy. The purpose of this review is to provide a thorough discussion and detailed presentation of the technical aspects of radioembolization specifically as it pertains to the implantation devices. Normal vascular anatomy, commonly encountered variants, and factors involved in changes to regional perfusion in the presence of liver tumors are discussed. In addition, the basic principles described in this manuscript apply to all liver-directed transarterial therapies, such as chemoembolization and/or drug-eluting microspheres.

  20. 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.

  1. Production of monodisperse silica gel microspheres for bioencapsulation by extrusion into an oil cross-flow.

    Science.gov (United States)

    Benson, Joey J; Wackett, Lawrence P; Aksan, Alptekin

    2016-06-29

    Silica gel microspheres are ideal materials for bioencapsulation due to their mechanical properties, biocompatibility, and stability. Encapsulated cells are isolated from the environment and protected from predators, changes in pH, and osmotic stress. However methods for the production of silica gel microspheres suitable for bioencapsulation are not well established. This paper describes a method for the production of monodisperse silicon alkoxide cross-linked silica nanoparticle (SNP) gel microspheres for bioencapsulation in which silica gel precursor is extruded from a needle into a cross-flowing stream of mineral oil. Microspheres produced ranged from 1.3 to 2.9 mm in diameter with coefficients of variation ranging from 2 to 6%. Microsphere size was mainly controlled by the flowrate of the cross-flowing oil and smaller microspheres generally had larger coefficients of variation. The method described in this paper can be optimised to produce silica gel microspheres with a diverse range of compositions and properties.

  2. Facile fabrication of various zinc-nickel citrate microspheres and their transformation to ZnO-NiO hybrid microspheres with excellent lithium storage properties

    Science.gov (United States)

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2015-02-01

    Zinc-nickel citrate microspheres are prepared by a simple aging process of zinc citrate solid microspheres in nickel nitrate solution. As the concentration of nickel nitrate solution increases, the morphology of the produced zinc-nickel citrate evolves from solid, yolk-shell to hollow microspheres. The formation mechanism of different zinc-nickel citrate microspheres is discussed. After annealing treatment of the corresponding zinc-nickel citrate microspheres in air, three different ZnO-NiO hybrid architectures including solid, yolk-shell and hollow microspheres can be successfully fabricated. When applied as the anode materials for lithium ion batteries, ZnO-NiO hybrid yolk-shell microspheres demonstrate the best electrochemical properties than solid and hollow counterparts. After 200th cycles, ZnO-NiO hybrid yolk-shell microspheres deliver a high reversible capacity of 1176 mA h g-1. The unique yolk-shell configuration, the synergetic effect between ZnO and NiO and the catalytic effect of metal Ni generated by the reduction of NiO during discharging process are responsible for the excellent lithium storage properties of ZnO-NiO hybrid yolk-shell microspheres.

  3. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun, E-mail: hxjzxh@zju.edu.cn

    2016-11-30

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  4. Increased transfer of iron to the fetus after total dose infusion of iron dextran during pregnancy.

    OpenAIRE

    Bingham, D; Khalaf, M.M.; Walters, G; Whicher, J T

    1983-01-01

    After total dose infusion of iron dextran to 14 pregnant women the saturation of transferrin and the concentration of ferritin were increased in the cord blood at birth, compared with untreated cases. These changes suggest that the fetal iron stores may be increased by such treatment.

  5. Amphiphilic starlike dextran wrapped superparamagnetic iron oxide nanoparticle clsuters as effective magnetic resonance imaging probes.

    Science.gov (United States)

    Su, Hongying; Liu, Yanhong; Wang, Dan; Wu, Changqiang; Xia, Chunchao; Gong, Qiyong; Song, Bin; Ai, Hua

    2013-01-01

    Starlike polymers have been widely used in various fields, such as tissue engineering, imaging, gene and drug delivery because of their unique structures and properties. Dextran has long been used as a temporary plasma substitute because of its excellent biocompatibility. In this study, starlike polysaccharide with multiple dextran arms was designed and developed by attaching dextran to a β-cyclodextrin core through click chemistry. Next, starlike dextran was modified with aliphatic chains and these amphiphilic polymers can self-assemble into nanoscale micelles in water, and their critical micelle concentration values (3.7 × 10(-8) M) are much lower comparing to its linear analogs (1.7 × 10(-7) M), resulting in more stable nanostructures in aqueous environment. These micelles can encapsulate multiple superparamagnetic iron oxide nanoparticles and forming clustering particle nanostructures in water, and the resulting nanocomposites have a high T(2) relaxivity of 436.8 Fe mm(-1) s(-1) under a 1.5T clinical magnetic resonance imaging (MRI) scanner. Further, dual functional probes were developed by loading both superparamagnetic iron oxide nanoparticles and small molecule anticancer drug doxorubicin into polymeric micelles. Multidrug-resistant breast cancer cells MCF-7/Adr treated with these probes can be characterized under MRI. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. [Treatment of iron deficiency by a bolus intravenous iron dextran in peritoneal dialysis].

    Science.gov (United States)

    Ficheux, Maxence; Cuny, Pascale; Lecouf, Angélique; Ryckelynck, Jean-Philippe; Hurault de Ligny, Bruno; Lobbedez, Thierry

    2011-12-01

    The main objective of this study is to determine whether a single dose of iron dextran can correct iron deficiency during a period of four months in peritoneal dialysis patients. This was a prospective observational study in peritoneal dialysis patients who had anemia (hemoglobiniron deficiency (ferritiniron or who could not tolerate oral iron were included in the study. At baseline, based on the iron deficiency estimation, a single dose of iron dextran was infused over four hours. Of 17 patients included, 12 completed the study. The mean iron dose infused was 742±150mg. No clinically significant adverse event was reported during the infusion. Four months after the iron dextran infusion there was a significant increase of the mean hemoglobin level (10.1±0.7g/dl vs 11.4±1.2g/dL, Piron infusion 10 patients had a blood ferritin level higher than 100μg/L and a transferrin saturation higher than 20%. There was no significant modification of the erythropoietin dose during the four months period. In patients treated by peritoneal dialysis, the anemia due to iron deficiency can be treated by a single infusion of iron dextran for a period of four months. Copyright © 2011 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

  7. Kinetics of dextran crosslinking by epichlorohydrin: a rheometry and equilibrium swelling study.

    Science.gov (United States)

    Emami Meybodi, Zahraalsadat; Imani, Mohammad; Atai, Mohammad

    2013-02-15

    Curing behavior and gel properties of dextran are investigated during its crosslinking by epichlorohydrin (ECH) using rheometry and equilibrium swelling studies. Each ECH/anhydroglucose unit of different molar ratio (0.16-0.99) was added to a known volume of aqueous dextran solution (25%, w/w) in the presence of sodium hydroxide (1.2-3.6 M) as a catalyst. Gel point was investigated as a function of the reactants concentration. The rheological behavior of the curing gels was evaluated using a rheokinetic model. Swelling behavior of the cured, cylindrical specimens was also studied gravimetrically. Increasing NaOH and ECH concentrations significantly increased the crosslinking reaction rate leading to shorter gel points, which was attributed to more ionization of hydroxyl functional groups of dextran due to higher NaOH concentrations. Degree of swelling vs. the reaction time was decreased sharply as a direct function of increasing NaOH and ECH concentrations up to certain levels, which then leveled off. In contrast, higher NaOH concentrations increased the swelling ratio probably due to the alkaline induced degradation of dextran chains. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Chitosan-dextran sulfate hydrogels as a potential carrier for probiotics

    DEFF Research Database (Denmark)

    Yucel Falco, Cigdem; Falkman, Peter; Risbo, Jens

    2017-01-01

    Physical and chemical (crosslinked with genipin) hydrogels based on chitosan and dextran sulfate were developed and characterized as novel bio-materials suitable for probiotic encapsulation. The swelling of the hydrogels was dependent on the composition and weakly influenced by the pH of the media...

  9. Leg amputation following intramuscular injection of iron dextran in a 32 year old woman

    Directory of Open Access Journals (Sweden)

    Gloria Shalviri

    2015-10-01

    Full Text Available To inform healthcare professionals of a rare serious reaction leading to leg amputation following intramuscular injection of iron dextran and report comments for preventing such reactions.A case of leg amputation following intramuscular injection of iron dextran reported to Iranian Pharmacovigilance Center was reviewed. Patient and reaction data was collected by assessing the reported yellow card, patient chart review and interviewing with patient and physicians. World Health Organization definition for serious reactions was used to determine the seriousness of the reaction. Naranjo algorithm was used to determine probability scale. The probability of the reaction was determined based on questionnaire of Schumock et al. The studied case is classified as a rare and serious but preventable reaction induced by intramuscular injection of iron dextran in a 32 year old woman. The probability of the reaction is appeared to be “probable” based on Naranjo algorithm. It seems that Iron dextran could cause serious and life threatening adverse effects. It is necessary for healthcare professionals to be informed of such rare but serious reaction in order to apply preventive actions.

  10. Iron dextran in the treatment of iron-deficiency anaemia of ...

    African Journals Online (AJOL)

    deficiency anaemia were randomly allocated to two treatment groups. Group A received the usual recommended dose of iron dextran (Imferon; Fisons) and group 8 received two-thirds of the recommended dose. A further 30 patients received oral iron ...

  11. Phase separation of aqueous mixtures of poly(ethylene oxide) and dextran

    NARCIS (Netherlands)

    Edelman, M.W.; Linden, van der E.; Tromp, R.H.

    2003-01-01

    Abstract: The phase behavior of aqueous mixtures of poly(ethylene oxide) (PEO) and dextran is studied as a function of the polymer concentration, the PEO molar mass, and temperature. The molar mass distributions of the two polymers in the coexisting phases are measured. From the temperature

  12. Multistaged Nanovaccines Based on Porous Silicon@Acetalated Dextran@Cancer Cell Membrane for Cancer Immunotherapy

    DEFF Research Database (Denmark)

    Fontana, Flavia; Shahbazi, Mohammad Ali; Liu, Dongfei

    2017-01-01

    A novel porous silicon (Psi)-based nanovaccines for cancer immunotherapy was developed by nanoprecipitation in glass capillary microfluidics. One of these systems, thermally oxidized Psi (TOPSi)@AcDEX (Acetalated dextran), was then encapsulated with vesicles derived from cancer cells, in order...

  13. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    Czech Academy of Sciences Publication Activity Database

    Sipošová, K.; Pospíšková, K.; Bednáriková, Z.; Šafařík, Ivo; Šafaříková, Miroslava; Kubovčíková, M.; Kopčanský, P.; Gázová, Z.

    2017-01-01

    Roč. 427, April (2017), s. 48-53 ISSN 0304-8853 Institutional support: RVO:60077344 Keywords : amyloid aggregation * nanoparticles * magnetic fluid * dextran * insulin Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.630, year: 2016

  14. Leuconostoc mesenteroides NRRL B-1149 as probiotic and its dextran with anticancer properties

    Directory of Open Access Journals (Sweden)

    RISHIKESH SHUKLA

    2014-04-01

    Full Text Available Leuconostoc mesenteroides NRRL B-1149 was evaluated for its probiotic properties. It displayed in vitro cell surface traits in terms of hydrophobicity, autoaggregation property and cell adhesive capacity on HeLa, murine macrophage and HT29 cell lines, which revealed its capability to adhere and colonize the intestine. The tolerance to various biological barriers such as lysozyme (100 μg/ml, gastric juice (pH 3.0 and bile salts (0.5%, w/v with 92%, 61.6% and 219% growth, respectively, confirmed its ability to survive in extreme conditions of digestive tract. It showed bile salts hydrolase activity signifying its ability to deconjugate bile salts. The whole cells of Leuconostoc mesenteroides B-1149 showed β-galactosidase activity with 94 Miller units displaying its importance in lactose utilization. The effect of dextran from Leuconostoc mesenteroides B-1149 having α-(1,6 linear glycosidic linkages and α-(1,3 branching was evaluated against cervical cancer (HeLa and colon cancer (HT29 cell lines. The dextran from L. mesenteroides B-1149 (100 μg/ml showed 25% inhibition of HeLa cell lines and 1000 μg/ml dextran displayed 40% inhibition of HT29 cell lines. The effect of dextran on murine monocyte-macrophage line (J774A.1 showed increase in growth of macrophages confirming its biocompatible nature.

  15. Tuning complement activation and pathway through controlled molecular architecture of dextran chains in nanoparticle corona.

    Science.gov (United States)

    Coty, Jean-Baptiste; Eleamen Oliveira, Elquio; Vauthier, Christine

    2017-11-05

    The understanding of complement activation by nanomaterials is a key to a rational design of safe and efficient nanomedicines. This work proposed a systematic study investigating how molecular design of nanoparticle coronas made of dextran impacts on mechanisms that trigger complement activation. The nanoparticles used for this work consisted of dextran-coated poly(isobutylcyanoacrylate) (PIBCA) nanoparticles have already been thoroughly characterized. Their different capacity to trigger complement activation established on the cleavage of the protein C3 was also already described making these nanoparticles good models to investigate the relation between the molecular feature of their corona and the mechanism by which they triggered complement activation. Results of this new study show that complement activation pathways can be selected by distinct architectures formed by dextran chains composing the nanoparticle corona. Assumptions that explain the relation between complement activation mechanisms triggered by the nanoparticles and the nanoparticle corona molecular feature were proposed. These results are of interest to better understand how the design of dextran-coated nanomaterials will impact interactions with the complement system. It can open perspectives with regard to the selection of a preferential complement activation pathway or prevent the nanoparticles to activate the complement system, based on a rational choice of the corona configuration. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Pterins as Sensors of Response to the Application of Fe3+-Dextran in Piglets

    Directory of Open Access Journals (Sweden)

    Klara Breinekova

    2010-01-01

    Full Text Available The aim of the presented study was to assess the effect of a single administration of Fe3+-dextran on immune cell counts and pterin biomolecule production as novel sensors of the piglets' immune system activation, and to determine concentrations of cortisol, a traditional hormonal biosensor of the stress response. Pterins (neopterin and biopterin in the piglets' blood serum were analyzed by separation using reversed-phase HPLC. A single dose of Fe3+-dextran produced a special stress situation in the piglets' organism which manifested itself by an increased production of neopterin (p < 0.05 and biopterin (p < 0.01 in the experimental piglets. Changes in cortisol concentrations and leukocyte counts were influenced by handling stress and were not specifically correlated to iron dextran application. Iron concentrations in the internal environment of the experimental piglets’ group were higher by an order of magnitude compared with the controls, and the highest serum concentrations of iron (p < 0.01 were reached 24 h following Fe3+-dextran administration. The data presented offer a new perspective on the evaluation of stress situations in the animal organism and, not least importantly, extends the rather modest current list of references on the role of pterins in livestock animals.

  17. One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles.

    Science.gov (United States)

    Hussain, Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Tahir, Muhammad Nawaz; Shah, Muhammad Raza; Ahmed, Riaz; Bukhari, Syed Nasir Abbas

    2014-12-03

    Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. UV-vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies showed spherical Ag NPs in the size regime of ~50-70 nm. Face centered cubic lattice of Ag NPs was confirmed by powder X-ray diffraction (PXRD). FT-IR spectroscopy confirmed that dextran not only acts as reducing agent but also functionalizes the surfaces of Ag NPs to make very stable dispersions. Moreover, on drying, the solution of dextran stabilized Ag NPs resulted in the formation of thin films which were found stable over months with no change in the plasmon band of pristine Ag NPs. The antimicrobial assay of the as synthesized Ag NPs showed remarkable activity. Being significantly active against microbes, the Ag NPs can be explored for antimicrobial medical devices.

  18. Synthesis and characterization of Schiff base contained dextran microgels in water-in-oil inverse microemulsion.

    Science.gov (United States)

    Su, Hongying; Jia, Qingming; Shan, Shaoyun

    2016-11-05

    Polysaccharide-based microgels with high water content, excellent biocompatibility and controllable particle size have been widely studied as ideal candidates for drug release and delivery. In this study, microgels based on dextran were developed via the Schiff base formation between aldehyded dextran and ethylenediamine in a water-in-oil (W/O) microemulsion. Particle size of the resulted microgel was controllable between 800 and 1100nm by modulating the amount of the employed co-surfactants (Span 80/Tween 80). Furthermore, fluoresceins (e.g., aminofluorescein) and drugs (e.g., doxorubicin) with free amino groups can be conjugated onto the network of the dextran-based microgel via Schiff base linkages. Since the Schiff base linkages are degradable via hydrolysis and their stability decreases with the environmental pH decreases, the resulted Schiff bases contained microgel showed a pH dependent degradation profile. These results indicated that the pH-sensitive microgel based on dextran could be used as promising drug delivery systems for biomedical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Phase separation induced fractionation in molar mass in aqueous mixtures of gelatin and dextran

    NARCIS (Netherlands)

    Edelman, M.W.; Tromp, R.H.; Weenen, H.

    2003-01-01

    An overview of the effects of phase separation of aqueous mixtures of gelatin and dextran on the fractionation in molar mass of these two components is given. Molar mass distributions in coexisting phases were investigated using size exclusion chromatography with multiangle laser light scattering.

  20. Biodegradable poly(lactic acid) microspheres containing total ...

    Indian Academy of Sciences (India)

    Administrator

    herbal, can relieve symptom of rheumatosis, blood segre- gation and pain .... All samples demon- strated an initial burst of drug release, about 20–40% of the total within the first 2 h of incubating. Thereafter. Figure 3. FT–IR spectra of (a) PLA; (b) PLA microspheres ... spheres will take more time to gradually move from the.

  1. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    Centre for Advanced Technology (CAT), Indore 452 013, India. MS received 26 June 2001; revised 7 December 2001. Abstract. Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fu- sion, is a means of producing energy by imploding small hollow microspheres containing thermo- nuclear fusion ...

  2. Method for forming microspheres for encapsulation of nuclear waste

    Science.gov (United States)

    Angelini, Peter; Caputo, Anthony J.; Hutchens, Richard E.; Lackey, Walter J.; Stinton, David P.

    1984-01-01

    Microspheres for nuclear waste storage are formed by gelling droplets containing the waste in a gelation fluid, transferring the gelled droplets to a furnace without the washing step previously used, and heating the unwashed gelled droplets in the furnace under temperature or humidity conditions that result in a substantially linear rate of removal of volatile components therefrom.

  3. An all-fiber coupled multicolor microspherical light source

    NARCIS (Netherlands)

    O'Shea, Danny G.; Ward, Jonathan M.; Shortt, Brian J.; Chormaic, Sile Nic

    2007-01-01

    We present results on the realization of an all-taper coupled, multicolor microspherical light source fabricated,from the erbium-doped fluoride glass ZBLALiP. Whispering gallery mode lasing at 1555 nm and fluorescent emissions from the ultraviolet to the infrared (IR) have been observed. A tapered

  4. Development of activity standard for 90Y microspheres

    CSIR Research Space (South Africa)

    Mo, L

    2005-08-01

    Full Text Available 90Y is a therapeutic radiopharmaceuticals used in the treatment of liver cancer following implantation via a catheter in the hepatic artery, 90Y microspheres are embolised in the microvasculature of liver cancer where they irradiate the tumour by a...

  5. Improved antireflection coated microspheres for biological applications of optical tweezers

    Science.gov (United States)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David

    2016-09-01

    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  6. Lacidipine encapsulated gastroretentive microspheres prepared by chemical denaturation for pylorospasm.

    Science.gov (United States)

    Sultana, S; Bhavna; Iqbal, Z; Panda, B P; Talegaonkar, S; Bhatnagar, A; Ahmad, F J

    2009-08-01

    The purpose of this research work was to formulate and systematically evaluate in vitro performance of mucoadhesive microspheres of lacidipine for treatment of pylorospasm. Lacidipine microspheres containing chitosan were prepared by chemical denaturation using glutaraldehyde as a cross-linking agent. The microspheres were evaluated for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy, drug entrapment efficiency and in vitro mucoadhesion. Results of preliminary trials indicated that the polymer concentration, cross-linking agent and stirring speed had a noticeable effect on size and surface morphology. A central composite design was employed to study the effect of independent variables, polymer concentration (X(1)), volume of glutaraldehyde (X(2)), stirring speed (X(3)) and cross-linking time (X(4)) on dependent variables, drug entrapment efficiency and percentage mucoadhesion. The entrapment efficiency varied from 14-40.82% depending upon the polymer concentration, volume of cross-linker and stirring speed. All batches of microspheres exhibited good mucoadhesive property (73-83%) in the in vitro wash-off test. It was observed that polymer concentration and glutaraldehyde volume had a more significant effect on the dependent variables. Maximum entrapment (36.53%) and mucoadhesion (81.33%) was predicted at 3.5% chitosan, 3 ml glutaraldehyde, 3000 rpm stirring speed and 75 min cross-linking time under optimized process condition. The selected formulation showed controlled release for more than 6 h. The release followed Higuchi kinetics via a Fickian diffusion.

  7. [Study on preparation process of artesunate polylactic acid microspheres].

    Science.gov (United States)

    Pan, Xu-Wang; Wang, Wei; Fang, Hong-Ying; Wang, Fu-Gen; Cai, Zhao-Bin

    2013-12-01

    This study aims to investigate the preparation process and in vitro release behavior of artesunate polylactic acid microspheres, in order to prepare an artesunate polylactic acid (PLA) administration method suitable for hepatic arterial embolization. With PLA as the material and polyvinyl alcohol (PVA) as the emulsifier, O/W emulsion/solvent evaporation method was adopted to prepare artesunate polylactic acid microspheres, and optimize the preparation process. With drug loading capacity, encapsulation efficiency and particle size as indexes, a single factor analysis was made on PLA concentration, PVA concentration, drug loading ratio and stirring velocity. Through an orthogonal experiment, the optimal processing conditions were determined as follows: PLA concentration was 9. 0% , PVA concentration was 0. 9% , drug loading ratio was 1:2 and stirring velocity was 1 000 r x min(-1). According to the verification of the optimal process, microsphere size, drug loading and entrapment rate of artesunate polylactic acid microspheres were (101.7 +/- 0.37) microm, (30.8 +/- 0.84)%, (53.6 +/- 0.62)%, respectively. The results showed that the optimal process was so reasonable and stable that it could lay foundation for further studies.

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

    African Journals Online (AJOL)

    Admin

    maximum by dissolving the layers of rough surface of polymer. The formulation F2 showed biphasic pattern i.e. initial fast release (as above. 50 % in only ½ h) called as burst effect, due to the large size of pores on the surface of microspheres and then sustained release due to smooth surface. The formulation F3 showed the.

  9. Remediation of coal mining wastewaters using chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Geremias, R.; Pedrosa, R.C.; Benassi, J.C.; Favere, V.T.; Stolberg, J.; Menezes, C.T.B.; Laranjeira, M.C.M. [Federal University of Santa Catarina, Florianopolis (Brazil)

    2003-12-01

    This study aimed to evaluate the potential use of chitosan and chitosan/poly(vinylalcohol) microspheres incorporating tetrasulphonated copper (II) phthalocyanine (CTS / PVA / TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace-metal concentration, as well as bioindicators of water pollution were used to that end. Wastewater samples collected from drainage of underground coal mines, decantation pools, and contaminated rivers were scrutinized. Acute toxicity tests were performed using the Brine Shrimp Test (BST) in order to evaluate the remediation efficiency of different treatments. The results showed that the pH of treated wastewater samples were improved to values close to neutrality. Chitosan treatments were also effective in removing trace-metals. Pre-treatment with chitosan followed by microsphere treatment (CTS / PVA / TCP) was more effective in decreasing toxicity than the treatment using only chitosan. This was probably due to the elimination of pollutants other than trace-metals. Thus, the use of chitosan and microspheres is an adequate alternative towards remediation of water pollution from coal mining.

  10. Microfluidic pump based on arrays of rotating magnetic microspheres

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; de Weerd, Eddy L; Abelmann, Leon; Bomer, Johan G.; van den Berg, Albert; Eijkel, Jan C.T.; Fujii, T.; Hibara, A.; Takeuchi, S.; Fukuba, T.

    2012-01-01

    We demonstrate a novel, flexible and biocompatible method to pump liquid through microchannels without the use of an external pump. The pumping principle is based on the rotation of superparamagnetic microspheres around permalloy disks, driven by an external in-plane rotating magnetic field. By

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

    Science.gov (United States)

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

    2015-08-20

    Controlled release fertilizers are efficient tools that increase the sustainability of agricultural practices. However, the biodegradability of the matrices and the determination of the release into soil still require some investigation. This paper describes the preparation of potassium-containing microspheres based on chitosan and montmorillonite clay and the in situ soil release. The chitosan-montmorillonite microspheres were prepared using a coagulation method and different proportions of montmorillonite. The structural, thermal and morphological properties as well the water swelling and fertilizer sorption capacity were evaluated. The best formulations were applied in soil, and the fertilizer release was monitored using time-domain reflectometry (TDR). Montmorillonite clay provides better sorption properties than the chitosan microspheres because of the rough and porous surface. Due to these properties, high levels of fertilizer were sorbed onto the material. ChMMT33-containing potassium shows two specific periods of fertilizer release: the first one lasted approximately three days and was assigned to the external fertilizer on the microspheres. The second was assigned to the internal fertilizer. TDR is an important and fast tool and was used to determine the fertilizer release and the ion movement in the soil. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    African Journals Online (AJOL)

    Purpose: The objective of this study was to formulate and evaluate a matrix microsphere system for simultaneous delivery of two anti-asthmatic drugs Salbutamol sulphate and Theophylline which are often indicated for the management of asthma, their frequent dosing may reduce compliance, thus making a prolonged ...

  13. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

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

    2015-07-01

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

  14. PtNi nanoparticles embedded in porous silica microspheres as ...

    Indian Academy of Sciences (India)

    Supported Pt-based alloy nanoparticles have attracted greater attention in catalysis due to their high activity, reduced cost, and easy recycling in chemical reactions. In this work, mesoporous SiO₂ microspheres were employed as support to immobilize PtNi alloy nanocatalysts with different mass ratios of Pt and Ni (1:0, 3:1, ...

  15. Albumin-heparin microspheres as carriers for cytostatic agents

    NARCIS (Netherlands)

    Cremers, Harry; Feijen, Jan; Kwon, G.; Bae, Y.H.; Kim, S.W.; Noteborn, H.P.J.M.; Mcvie, J.G.

    1990-01-01

    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation

  16. A microfluidic approach to assembling ordered microsphere arrays

    Science.gov (United States)

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

    2008-07-01

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

  17. Floating microspheres as drug delivery system: newer approaches.

    Science.gov (United States)

    Jain, Sunil K; Agrawal, Govind P; Jain, Narendra K

    2008-07-01

    A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI) transit time and the non-uniformity of drug absorption throughout the alimentary canal. Floating drug delivery systems (FDDSs) are expected to remain buoyant in a lasting way upon the gastric contents and consequently to enhance the bioavailability of drugs. The various buoyant preparations include hollow microspheres, granules, powders, tablets, capsules, pills and laminated films. Floating microspheres are specially gaining attention due to their wide applicability in the targeting of drugs to stomach. These floating microspheres have the advantage that they remain buoyant and distributed uniformly over the gastric fluid to avoid the vagaries of gastric emptying and release the drug for prolonged period of time. A major drawback of low-density floating drug delivery systems is that their performance is strongly dependent upon the gastric emptying process of stomach. Multiparticulate low-density particles can successfully prolong the gastric retention time of drugs. This article is a review of two important approaches utilized to prepare and improve the performance of floating microspheres.

  18. Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    McClure, Zachary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Padilla Cintron, Cristina [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-27

    Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology creates monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.

  19. Hydrogel microspheres from biodegradable polymers as drug delivery systems

    Science.gov (United States)

    A series of hydrogel microspheres were prepared from pectin, a hydrophilic biopolymer, and zein, a hydrophobic biopolymer, at varying weight ratios. The hydrogel formulation was conducted in the presence of calcium or other divalent metal ions at room temperature under mild conditions. Studies of ...

  20. Development and Evaluation of Floating Microspheres of Curcumin

    African Journals Online (AJOL)

    vitro floatability and ... methane, 1:1) as per the composition in. Table 1 ... to bulk density. Evaluation of angle of repose. The angle of repose of the microspheres, which measures the resistance to particle flow, was determined by the fixed funnel.

  1. Immunochemical analysis of the idiotypes of mouse myeloma proteins with specificity for levan or dextran.

    Science.gov (United States)

    Weigert, M; Raschke, W C; Carson, D; Cohn, M

    1974-01-01

    This paper deals solely with idiotypic determinants, the configurations of which are modified when the antibody bearing them interacts with its ligand. This phenomenon is measured as an inhibition of the reaction between anti-idiotype and idiotype. Two points are made: (a) The assay for ligand-modifiable determinants can be used to determine the "size" of the combining site. This is illustrated here with the anti-alpha(1 --> 6) dextran mouse myeloma immunoglobulin W3129. Whether the interaction between a homologous series of alpha(1 --> 6) oligosaccharide ligands and the combining site of W3129 is measured by inhibition of precipitation with alpha(1 --> 6) dextran (4) or of binding of W3129 to anti-W3129 idiotype, the finding is the same. The order of inhibition is isomaltohexaose = isomaltopentaose > isomaltotetraose > isomaltotriose > isomaltose. The combining site is optimally complementary to isomaltopentaose. (b) Cross-idiotypic specificity is closely correlated with cross-combining specificity; the converse is not true. This is illustrated here with three groups of mouse myeloma immunoglobulin, each specific for alpha(1 --> 3) dextran, alpha(1 -->6) dextran, beta(2 --> 1) or beta(2 --> 6) levan. If a given anti-idiotypic serum cross-reacted with several myeloma proteins, they always had similar combining specificity. Thus the three proteins, J558, MOPC 104E, and UPC 102, which cross-react with anti-J558 have combining specificity for alpha(1 --> 3) dextran; cross-reacting W3082, UPC 61, and Y5476 have specificity for levan; and cross-reacting W3129 and W3434 have specificity for alpha(1 --> 6) dextran. This extends previous studies with proteins specific for phosphorylcholine (7) or gamma-globulin (8). As expected, the converse is not true, for proteins may have combining specificity for alpha(1 --> 6) dextran e.g. QUPC 52, or levan e.g. J606, UPC 10 and yet not carry the above-mentioned reference idiotypes. The correlation between cross-idiotypic and

  2. Synthesis and catalytic performance of SiO2@Ni and hollow Ni microspheres

    Science.gov (United States)

    Liu, Xin; Liu, Yanhua; Shi, Xueting; Yu, Zhengyang; Feng, Libang

    2016-11-01

    Nickel (Ni) catalyst has been widely used in catalytic reducing reactions such as catalytic hydrogenation of organic compounds and catalytic reduction of organic dyes. However, the catalytic efficiency of pure Ni is low. In order to improve the catalytic performance, Ni nanoparticle-loaded microspheres can be developed. In this study, we have prepared Ni nanoparticle-loaded microspheres (SiO2@Ni) and hollow Ni microspheres using two-step method. SiO2@Ni microspheres with raspberry-like morphology and core-shell structure are synthesized successfully using SiO2 microsphere as a template and Ni2+ ions are adsorbed onto SiO2 surfaces via electrostatic interaction and then reduced and deposited on surfaces of SiO2 microspheres. Next, the SiO2 cores are removed by NaOH etching and the hollow Ni microspheres are prepared. The NaOH etching time does no have much influence on the crystal structure, shape, and surface morphology of SiO2@Ni; however, it can change the phase composition evidently. The hollow Ni microspheres are obtained when the NaOH etching time reaches 10 h and above. The as-synthesized SiO2@Ni microspheres exhibit much higher catalytic performance than the hollow Ni microspheres and pure Ni nanoparticles in the catalytic reduction of methylene blue. Meanwhile, the SiO2@Ni catalyst has high stability and hence it can be recycled for reuse.

  3. [Pharmaco-physiologic correlations of iron-dextran complexes in laboratory animals].

    Science.gov (United States)

    Dilov, P

    1986-01-01

    Investigated were the Bulgarian preparation dextrofer-100 (Pharmachim) and miofer-100 (Farbwerke, Hoechst, West Germany)--iron-dextran preparations with 100 mg Fe3+/cm3 each. Use was made of 62 domestic cats, 8 guinea pigs, and 18 albino rats. tI was found that the venous introduction of iron-dextran complexes into uretane-treated cats at rates of 100 to 500 mg Fe3+/kg body mass lowered the blood pressure by 10 to 65 per cent; the depressive effect was more strongly manifested with the use of miofer-100. At 100 mg Fe3+/kg and higher doses led to alfa-adrenolytic manifestations (an inverse effect of noradrenaline), and did not change the action of acetyl-choline, histamine, and serotonin. At venous injection the iron-dextran complexes diminished the amplitudes of the heart contractions (with cats in situ). With regard to the nervous-and-muscle condition these preparations were found to manifest an action that resembled that of curare (the effect produced by miofer was stronger). Dextrofer-100 in a five-fold application to guinea pigs at the rate of 0.2 cm3+ (= 20 mg Fe3+) blocked the sensibilizing action of horse serum--it gave protection from an aphylactic shock in about 70 per cent of the animals. In muscular application to albino rats with experimentally induced dextran edema this preparation manifested an antiedema action. The iron-dextran complexes lowered the contraction capacity of ileum sections (taken from guinea pigs) that was manifested under the action of serotonin and histamine.

  4. Hydroxyethyl starch as a substitute for dextran 40 for thawing peripheral blood progenitor cell products.

    Science.gov (United States)

    Zhu, Fenlu; Heditke, Sarah; Kurtzberg, Joanne; Waters-Pick, Barbara; Hari, Parameswaran; Margolis, David A; Keever-Taylor, Carolyn A

    2015-12-01

    Removing DMSO post-thaw results in: reduced infusion reactions, improved recovery and stability of viable CD34+ cells. Validated methods use 5%-8.3% Dextran 40 with 2.5%-4.2% HSA for this purpose. Recent shortages of clinical grade Dextran require identification of suitable alternatives. PBPC were used to compare a standard 2X wash medium of 5 parts 10% Dextran 40 in saline (DEX) with 1 part 25% HSA (8.3% DEX/ 4.2% HSA) with Hydroxyethyl Starch (HES)-based solutions. Cells in replicate bags were diluted with an equal volume of wash solution, equilibrated 5 minutes, the bag filled with wash medium, pelleted and the supernatant expressed. Bags were restored to the frozen volume in wash medium and tested by single platform flow cytometry and CFU. Total viability, viable TNC, MNC, and CD34+ cell recovery, and CD34+ cell viability were compared immediately post-thaw and after 90 minutes. 5.2% HES/4.2% HSA did not differ from our standard in CD34 recovery or viability. Due to concerns that high concentrations of HES could affect renal function we tested 0.6% HES/2.5% HSA resulting in significantly poorer CD34 recovery and viability. Results improved using 2.4% HES/4.2% HSA and when 0.6% HES/4.2%HSA was used no significant differences were seen. CFU assays confirmed no differences between the standard dextran arm and HES at 2.4% or 0.6% so long as HSA was at 4.2%. We conclude that HES from 0.6% to 5.2% with 4.2% HSA is a suitable substitute for Dextran 40 as a reconstitution/washing medium for PBPC products. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  5. Functional analysis of truncated and site-directed mutagenesis dextransucrases to produce different type dextrans.

    Science.gov (United States)

    Wang, Chao; Zhang, Hong-Bin; Li, Meng-Qi; Hu, Xue-Qin; Li, Yao

    2017-07-01

    Dextrans with distinct molecular size and structure are increasingly being used in the food and pharmaceutical industries. Dextran is produced by dextransucrase (DSR, EC2.4.5.1), which is produced by Leuconostoc mesenteroides. DSR belongs to glycosyl hydrolase family (GH70) and synthesizes branched α-glucan (dextran) with both 5% α(1-3) and 95% α(1-6) glycosidic linkages. The DSR gene dex-YG (Genebank, Accession No. DQ345760) was cloned from the wild strain Leuconostoc mesenteroides 0326. This study generated a series of C-terminally truncated variants of dextransucrase and substituting the amino-acid residues in the active site of DSR. With shorter length of DSR, its polysaccharide-synthesizing capability was impaired heavily, whereas oligosaccharide (acting as prebiotics)-synthesizing capability increased significantly, efficiently producing special sizes of dextran. All truncated mutant enzymes were active. Results demonstrated that the catalytic domain dextransucrase was likely in 800 aa or less. Based on the three-dimensional structure model of dextransucrase built through homology modeling methods, the DSR and its mutants with the acceptor substrate of maltose and donor substrate of sucrose were studied by molecular-docking method. Substituting these amino-acid residues significantly affected enzyme activities. Compared with the wild-type dextran, mutant enzymes catalyzed the synthesis of a-glucan with 1-9% α(1-3) and 90-98% α(1-6) branching linkages. Some mutants introduced a small amount of α(1-4) linkages and α(1-2) linkages. This strategy can be effectively used for the rational protein design of dextransucrase. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. High impact of in situ dextran coating on biocompatibility, stability and magnetic properties of iron oxide nanoparticles.

    Science.gov (United States)

    Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

    2017-06-01

    Biocompatible ferrofluids based on dextran coated iron oxide nanoparticles were fabricated by conventional co-precipitation method. The experimental results show that the presence of dextran in reaction medium not only causes to the appearance of superparamagnetic behavior but also results in significant suppression in saturation magnetization of dextran coated samples. These results can be attributed to size reduction originated from the role of dextran as a surfactant. Moreover, weight ratio of dextran to magnetic nanoparticles has a remarkable influence on size and magnetic properties of nanoparticles, so that the sample prepared with a higher weight ratio of dextran to nanoparticles has the smaller size and saturation magnetization compare with the other samples. In addition, the ferrofluids containing such nanoparticles have an excellent stability at physiological pH for several months. Furthermore, the biocompatibility studies reveal that surface modification of nanoparticles by dextran dramatically decreases the cytotoxicity of bare nanoparticles and consequently improves their potential application for diagnostic and therapeutic purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Derivatization of Dextran for Multiply Charged Ion Formation and Electrospray Ionization Time-of-Flight Mass Spectrometric Analysis

    Science.gov (United States)

    Tapia, Jesus B.; Hibbard, Hailey A. J.; Reynolds, Melissa M.

    2017-10-01

    We present the use of a simple, one-pot derivatization to allow the polysaccharide dextran to carry multiple positive charges, shifting its molecular weight distribution to a lower m/ z range. We performed this derivatization because molecular weight measurements of polysaccharides by mass spectrometry are challenging because of their lack of readily ionizable groups. The absence of ionizable groups limits proton abstraction and suppresses proton adduction during the ionization process, producing mass spectra with predominantly singly charged metal adduct ions, thereby limiting the detection of large polysaccharides. To address this challenge, we derivatized dextran T1 (approximately 1 kDa) by attaching ethylenediamine, giving dextran readily ionizable, terminal amine functional groups. The attached ethylenediamine groups facilitated proton adduction during the ionization process in positive ion mode. Using the low molecular weight dextran T1, we tracked the number of ethylenediamine attachments by measuring the mass shift from underivatized to derivatized dextran T1. Using electrospray ionization time-of-flight mass spectrometry, we observed derivatized dextran chains ranging from two to nine glucose residues with between one and four attachments/charges. Our success in shifting derivatized dextran T1 toward the low m/ z range suggests potential for this derivatization as a viable route for analysis of high molecular weight polysaccharides using electrospray ionization time-of-flight mass spectrometry. [Figure not available: see fulltext.

  8. Investigation of urinary excretion of hydroxyethyl starch and dextran by uhplc-hrms in different acquisition modes.

    Science.gov (United States)

    Esposito, S; Deventer, K; Giron, A J; Roels, K; Herregods, L; Verstraete, A; Van Eenoo, P

    2014-06-01

    Plasma volume expanders (PVEs) such as hydroxyethyl starch (HES) and dextran are misused in sports because they can prevent dehydration and reduce haematocrit values to mask erythropoietin abuse. Endogenous hydrolysis generates multiple HES and dextran oligosaccharides which are excreted in urine. Composition of the urinary metabolic profiles of PVEs varies depending on post-administration time and can have an impact on their detectability. In this work, different mass spectrometry data acquisition modes (full scan with and without in-source collision-induced dissociation) were used to study urinary excretion profiles of HES and dextran, particularly by investigating time-dependent detectability of HES and dextran urinary oligosaccharide metabolites in post-administration samples. In-source fragmentation yielded the best results in terms of limit of detection (LOD) and detection times, whereas detection of HES and dextran metabolites in full scan mode with no in-source fragmentation is related to recent administration (< 24 hours). Urinary excretion studies showed detection windows for HES and dextran respectively of 72 and 48 hours after administration. Dextran concentrations were above the previously proposed threshold of 500 µg · mL(-1) for 12 hours. A "dilute-and-shoot" method for the detection of HES and dextran in human urine by ultra-high-pressure liquid chromatography-electrospray ionization-high resolution Orbitrap™ mass spectrometry was developed for this study. Validation of the method showed an LOD in the range of 10-500 µg · mL(-1) for the most significant HES and dextran metabolites in the different modes. The method allows retrospective data analysis and can be implemented in existing high-resolution mass spectrometry-based doping control screening analysis.

  9. INVESTIGATION OF URINARY EXCRETION OF HYDROXYETHYL STARCH AND DEXTRAN BY UHPLC-HRMS IN DIFFERENT ACQUISITION MODES

    Directory of Open Access Journals (Sweden)

    S. Esposito

    2014-07-01

    Full Text Available Plasma volume expanders (PVEs such as hydroxyethyl starch (HES and dextran are misused in sports because they can prevent dehydration and reduce haematocrit values to mask erythropoietin abuse. Endogenous hydrolysis generates multiple HES and dextran oligosaccharides which are excreted in urine. Composition of the urinary metabolic profiles of PVEs varies depending on post-administration time and can have an impact on their detectability. In this work, different mass spectrometry data acquisition modes (full scan with and without in-source collision-induced dissociation were used to study urinary excretion profiles of HES and dextran, particularly by investigating time-dependent detectability of HES and dextran urinary oligosaccharide metabolites in post-administration samples. In-source fragmentation yielded the best results in terms of limit of detection (LOD and detection times, whereas detection of HES and dextran metabolites in full scan mode with no in-source fragmentation is related to recent administration (< 24 hours. Urinary excretion studies showed detection windows for HES and dextran respectively of 72 and 48 hours after administration. Dextran concentrations were above the previously proposed threshold of 500 μg · mL-1 for 12 hours. A “dilute-and-shoot” method for the detection of HES and dextran in human urine by ultra-high-pressure liquid chromatography-electrospray ionization-high resolution Orbitrap™ mass spectrometry was developed for this study. Validation of the method showed an LOD in the range of 10-500 μg · mL-1 for the most significant HES and dextran metabolites in the different modes. The method allows retrospective data analysis and can be implemented in existing high-resolution mass spectrometry-based doping control screening analysis.

  10. High and Low Molecular Weight Fluorescein Isothiocyanate (FITC)-Dextrans to Assess Blood-Brain Barrier Disruption: Technical Considerations.

    Science.gov (United States)

    Hoffmann, Angelika; Bredno, Jörg; Wendland, Michael; Derugin, Nikita; Ohara, Peter; Wintermark, Max

    2011-03-01

    This note is to report how histological preparation techniques influence the extravasation pattern of the different molecular sizes of fluorescein isothiocyanate (FITC)-dextrans, typically used as markers for blood-brain barrier leakage. By using appropriate preparation methods, false negative results can be minimized. Wistar rats underwent a 2-h middle cerebral artery occlusion and magnetic resonance imaging. After the last imaging scan, Evans blue and FITC-dextrans of 4, 40, and 70 kDa molecular weight were injected. Different histological preparation methods were used. Sites of blood-brain barrier leakage were analyzed by fluorescence microscopy. Extravasation of Evans blue and high molecular FITC-dextrans (40 and 70 kDa) in the infarcted region could be detected with all preparation methods used. If exposed directly to saline, the signal intensity of these FITC-dextrans decreased. Extravasation of the 4-kDa low molecular weight FITC-dextran could only be detected using freshly frozen tissue sections. Preparations involving paraformaldehyde and sucrose resulted in the 4-kDa FITC-dextran dissolving in these reactants and being washed out, giving the false negative result of no extravasation. FITC-dextrans represent a valuable tool to characterize altered blood-brain barrier permeability in animal models. Diffusion and washout of low molecular weight FITC-dextran can be avoided by direct immobilization through immediate freezing of the tissue. This pitfall needs to be known to avoid the false impression that there was no extravasation of low molecular weight FITC-dextrans.

  11. Novel magnetic nanoparticles coated by benzene- and β-cyclodextrin-bearing dextran, and the sorption of polycyclic aromatic hydrocarbon

    DEFF Research Database (Denmark)

    Cho, Eunae; Tahir, Muhammad Nazir; Min Choi, Jae

    2015-01-01

    We present the synthesis of novel magnetic nanoparticles functionalized by benzene- and β-cyclodextrin-derivatized dextran. The grafting strategy was based on the [alkynyl-iron] cluster in the modified dextrans, which were prepared by click reaction from alkyne-modified dextran and benzyl azide...... or mono-6-O-deoxy-monoazido β-cyclodextrin. Characterization was then carried out by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. Using the developed magnetic nanoparticles...... to be significant. Furthermore, the polysaccharide derivative-coated magnetic adsorbents could be recovered by an external magnet for reuse....

  12. Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations

    Energy Technology Data Exchange (ETDEWEB)

    Högberg, Jonas, E-mail: jonas.hogberg@radfys.gu.se [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Rizell, Magnus [Department of Surgery, Sahlgrenska University Hospital, Gothenburg (Sweden); Hultborn, Ragnar; Svensson, Johanna [Department of Oncology, Sahlgrenska University Hospital, Gothenburg (Sweden); Henrikson, Olof [Department of Radiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Mölne, Johan [Department of Pathology, Sahlgrenska University Hospital, Gothenburg (Sweden); Gjertsson, Peter [Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Bernhardt, Peter [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden)

    2016-10-01

    Purpose: To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with {sup 90}Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Methods and Materials: Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-μm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Results: Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV=0.35, HDV = 50 cm{sup 3}, and ADR=6 μm. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 μm, respectively, whereas HDV increased to 130 cm{sup 3}. The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm{sup 3}, and ADR = 8 μm. Conclusion: Simulations and measurements reveal that microsphere clusters are

  13. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, Mariappan Parans; Liu, Hansan; Brown, Gilbert M.; Sun, Xiao-Guang; Bi, Zhonghe

    2016-12-06

    Compositions and methods of making are provided for mesoporous metal oxide microspheres electrodes. The mesoporous metal oxide microsphere compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g. The methods of making comprise forming composite powders. The methods may also comprise refluxing the composite powders in a basic solution to form an etched powder, washing the etched powder with an acid to form a hydrated metal oxide, and heat-treating the hydrated metal oxide to form mesoporous metal oxide microspheres.

  14. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Energy Technology Data Exchange (ETDEWEB)

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A; Brown, Gilbert M

    2014-12-16

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g, and wherein the composition has an electrical conductivity of at least 1.times.10.sup.-7 S/cm at 25.degree. C. and 60 MPa. The methods of making comprise forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere, (ii) doping with an aliovalent element, and (iii) coating with a coating composition.

  15. Preparation and evaluation of glyceryl monooleate-coated hollow-bioadhesive microspheres for gastroretentive drug delivery.

    Science.gov (United States)

    Liu, Yuanfen; Zhang, Jianjun; Gao, Yuan; Zhu, Jiabi

    2011-07-15

    The purpose of this study was to produce hollow and bioadhesive microspheres to lengthen drug retention time in the stomach. In these microspheres, ethylcellulose was used as the matrix, Eudragit EPO was employed to modulate the release rate, and glyceryl monooleate (GMO) was the bioadhesive polymer in situ. The morphological characteristics of the microspheres were defined using scanning electron microscopy. The in vitro release test showed that the release rate of drug from the microspheres was pH-dependent, and was not influenced by the GMO coating film. The prepared microspheres demonstrated strong mucoadhesive properties with good buoyancy both in vitro and in vivo. Pharmacokinetic analysis indicated that the elimination half-life time of the hollow-bioadhesive microspheres was prolonged, and that the elimination rate was decreased. In conclusion, the hollow-bioadhesive synergic drug delivery system may be advantageous in the treatment of stomach diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Drug-loaded biodegradable microspheres for image-guided combinatory epigenetic therapy in cells

    Science.gov (United States)

    Xu, Ronald X.; Xu, Jeff S.; Zuo, Tao; Shen, Rulong; Huang, Tim H.; Tweedle, Michael F.

    2011-02-01

    We synthesize drug-loaded poly (lactic-co-glycolic acid) (PLGA) microspheres for image-guided combinatory epigenetic therapy in MCF-10A human mammary epithelial cells. LY294002 and Nile Red are encapsulated in microspheres for sustained drug release and fluorescence microscopic imaging. Drug-loaded microspheres target MCF-10A cells through a three-step binding process involving biotinylated antibody, streptavidin, and biotinylated microspheres. LY294002 loaded microspheres and 5-Aza-2-deoxycytidine are applied to MCF-10A cells for combinatory PI3K/AKT inhibition and deoxyribonucleic acid (DNA) demethylation. Our study implies the technical potential of disease targeting and image-guided combinatory epigenetic therapy using drug-loaded multifunctional biodegradable PLGA microspheres.

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

    Science.gov (United States)

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

    2014-07-14

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

  18. INFLUÊNCIA DE DIFERENTES NÍVEIS DE FERRO DEXTRAN NO DESEMPENHO DE LEITÕES INFLUENCE OF DIFFERENT LEVELS OF IRON DEXTRAN IN THE PERFORMANCE OF PIGLETS

    Directory of Open Access Journals (Sweden)

    Alberto Marchatti Neto

    2007-09-01

    Full Text Available

    O presente estudo foi realizado na Fazenda Experimental de Felixlândia, Minas Gerais, e teve como objetivo estudar a influência de diferentes níveis de ferro dextran injetados, intramuscularmente, sobre o desempenho de leitões aos 21 e 35 dias de idade. A amostra tomada de um plantel de 120 matrizes e 8 varões constou de 16 leitegadas, provenientes de porcas da raça Large White, com a mesma ordem de parição, filhos do mesmo varão. Foram usadas quatro leitegadas para cada tratamento assim distribuídos: T1 - 100 mg de ferro dextran no 3° dia de vida; T2 - 50 mg de ferro dextran no 3° dia de vida e 50 mg de ferro dextran no 6° dia de vida; T3 - 100 mg de ferro dextran no 3° dia de vida e 100 mg no 12° dia de vida; T4 - 50 mg de ferro dextran no 3° dia de vida, 50 mg de ferro dextran no 6° dia, 50 mg de ferro dextran no 9° dia e 50 mg de ferro dextran no 12° dia de vida. O tratamento 2 possibilitou o melhor ganho de peso, tanto aos 21 como aos 35 dias. Quando se analisou os pesos médios aos 35 dias, verificou-se que os melhores tratamentos foram os de números 1 e 2. Esses resultados nos indicam que a dosagem de 100 mg de ferro dextran aplicada da uma só vez (T. 1, ou parcialmente (T. 2, nas condições que foi realizado o experimento foram as que obtiveram os melhores índices de peso médio aos 35 dias de vide dos leitões.

    The present investigation was carried out in the Experimental Farm in the County of Felixlândia, Minas Gerais State and had the objective of studying the influence of intramuscular injections of different levels of iron dextran in the development of piglets, evaluated at 21 and 35 days of age. Sixteen litters from Large White sows, from a herd of 120 sows and 8 boars, were used in these experiment. For each treatment it was used 4 litters as it follows: T1 - 100 mg of iron

  19. 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)

  20. POE-PEG-POE triblock copolymeric microspheres containing protein. I. Preparation and characterization.

    Science.gov (United States)

    Yang, Y Y; Wan, J P; Chung, T S; Pallathadka, P K; Ng, S; Heller, J

    2001-07-10

    Poly(ortho ester) (POE)-poly (ethylene glycol) (PEG) triblock copolymers (POE-PEG-POE) with different PEG contents were synthesised as carriers for controlled protein delivery. POE-PEG-POE microspheres containing bovine serum albumin (BSA) were prepared using a double-emulsion (water-in-oil-in-water) process. In this first paper of a two-part series, we report the fundamentals of the fabrication and characterization of POE-PEG-POE microspheres. Because the triblock copolymer is more hydrophilic than neat poly(ortho ester), the triblock copolymer yields a more stable first emulsion (water-in-oil) and a greater BSA encapsulation efficiency (90% vs. 30%). No BSA is found on POE-PEG-POE microsphere surfaces measured by X-ray photoelectron spectroscopy, while uniform BSA distributions are observed within the microspheres by confocal microscopy. SEM pictures show that an increase in PEG content results in microspheres with a denser cross-section because of a more stable first emulsion and better affinity between the copolymer and water. POE-PEG(20%)-POE suffers significant swelling during the fabrication process and yields the biggest microspheres. However, the POE-PEG(30%)-POE microspheres are much smaller since the dissolution loss of POE-PEG(30%)-POE in the external water phase may be much higher than that of POE-PEG(20%)-POE. The salt concentration in the external water phase significantly affects the morphology of the resultant microspheres. Microspheres with a dense wall are produced when using pure water as the external water phase. Polymer concentration has less impact on BSA encapsulation efficiency but has a considerable effect on microsphere size and morphology. Increasing the concentration of the polyvinyl alcohol emulsifier does not cause an obvious decrease in microsphere size. However, increased BSA loading results in bigger microspheres.

  1. EVALUATION OF ANTI-INFLAMMATORY AND ANTI-ARTHRITIC ACTIVITIES OF FLOATING MICROSPHERES OF HERBAL DRUG

    OpenAIRE

    Kapil Kumar; Rai, A. K.

    2012-01-01

    The aim of the present studies was to prepare and evaluate floating microspheres of curcumin for anti-inflammatory and anti-arthritic effect. Floating microsphere were prepared using hydroxyl propyl methylcellulose (HPMC), ethyl cellulose (EC), polyvinyl pyrrolidone K30 (PVPK30), eudragit RS 100 polymer in different ratio and dichloromethane and heavy liquid paraffin as solvent by emulsion solvent diffusion method. The floating microspheres were evaluated for flow properties based on paramet...

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

    OpenAIRE

    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 lysozyme on albumin-heparin microspheres was linear until saturation was abruptly reached, The adsorption isotherms of human lysozyme at low and high ionic strength were typical of adsorption isoth...

  3. Development of Floating-Mucoadhesive Microsphere for Site Specific Release of Metronidazole

    OpenAIRE

    Md. Lutful Amin; Tajnin Ahmed; Md. Abdul Mannan

    2016-01-01

    Purpose: The purpose of this study was to develop and evaluate metronidazole loadedfloating-mucoadhesive microsphere for sustained drug release at the gastric mucosa.Methods: Alginate gastroretentive microspheres containing metronidazole were preparedby ionic gelation method using sodium bicarbonate as gas forming agent, guar gum asmucoadhesive polymer, and Eudragit L100 as drug release modifier. Carbopol was used forincreasing the bead strength. The microspheres were characterized by scannin...

  4. Ultralow-threshold neodymium-doped microsphere lasers on a silicon chip

    Science.gov (United States)

    Ding, Yang; Fan, Huibo; Zhang, Xun; Jiang, Xiaoshun; Xiao, Min

    2017-07-01

    We demonstrate ultralow-threshold neodymium-doped silica microsphere lasers on a silicon chip with lasing wavelengths of 900 nm and 1060 nm. Neodymium-doped microsphere cavities are fabricated with a series of doping concentrations using silica sol-gel films. Experimentally, we observe single-mode lasing emissions from the high-Q microsphere cavities with a threshold of as low as 1.2 μW.

  5. 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.

  6. Preparation and evaluation of waxes/fat microspheres loaded with lithium carbonate for controlled release

    OpenAIRE

    Gowda D.; Shivakumar H

    2007-01-01

    To minimize the unwanted toxic effects of anti maniac drug lithium carbonate by kinetic control of drug release, it was entrapped into gastro resistant, biodegradable, waxes and fat such as beeswax, cetostearyl alcohol, spermaceti and cetylalcohol microspheres using meltable emulsified dispersion cooling induced solidification technique utilizing a wetting agent. Solid, discrete, reproducible free flowing microspheres were obtained. The yield of the microspheres was up to 90.0%. More t...

  7. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking

    DEFF Research Database (Denmark)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K

    2016-01-01

    , whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry......While having tremendous potential as therapeutic and imaging tools, the clinical use of engineered nanoparticles has been associated with serious safety concerns. Activation of the complement cascade and the release of proinflammatory factors C3a and C5a may contribute to infusion-related reactions...

  8. Synthesis of low-cost porous ceramic microspheres from waste gangue for dye adsorption

    National Research Council Canada - National Science Library

    Shu Yan; Yiming Pan; Lu Wang; Jingjing Liu; Zaijuan Zhang; Wenlong Huo; Jinlong Yang; Yong Huang

    2017-01-01

    .... Effects of calcination temperature on phase and microstructure evolution, specific surface area, pore structure, and dye adsorption mechanism of the microspheres were investigated systematically...

  9. Preparation of PLLA/bpV(pic) microspheres and their effect on nerve cells.

    Science.gov (United States)

    Lin, Qiang; Chen, Hai-yun; Li, Hao-shen; Cai, Yang-ting

    2014-02-01

    In this study, we prepared PLLA/bpV(pic) microspheres, a bpV(pic) controlled release system and examined their ability to protect nerve cells and promote axonal growth. PLLA microspheres were prepared by employing the o/w single emulsification-evaporation technique. Neural stem cells and dorsal root ganglia were divided into 3 groups in terms of the treatment they received: a routine medium group (cultured in DMEM), a PLLA microsphere group (DMEM containing PLLA microspheres alone) and a PLLA/bpV(pic) group [DMEM containing PLLA/bpV(pic) microspheres]. The effects of PLLA/bpV(pic) microspheres were evaluated by the live-dead test and measurement of axonal length. Our results showed that PLLA/bpV(pic) granulation rate was (88.2±5.6)%; particle size was (16.8±3.1)%, drug loading was (4.05±0.3)%; encapsulation efficiency was (48.5±1.8)%. The release time lasted for 30 days. In PLLA/bpV(pic) microsphere group, the cell survival rate was (95.2 ±4.77)%, and the length of dorsal root ganglion (DRG) was 718±95 μm, which were all significantly greater than those in ordinary routine medium group and PLLA microsphere group. This preliminary test results showed the PLLA/bpV(pic) microspheres were successfully prepared and they could promote the survival and growth of neural cells in DRG.

  10. Synthesis and characterization of magnesium gluconate contained poly(lactic-co-glycolic acid)/chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shekh M. [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Mahoney, Christopher [Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Sankar, Jagannathan [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Mechanical Engineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Marra, Kacey G. [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Department of Plastic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15250 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA 15250 (United States); Bhattarai, Narayan, E-mail: nbhattar@ncat.edu [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-01-15

    Graphical abstract: - Highlights: • Magnesium gluconate contained PLGA/chitosan microspheres were fabricated. • In vitro release of magnesium ions was performed using Xylidyl Blue assay. • Chitosan coated PLGA can significantly control the release of magnesium ions. • Cellular compatibility was tested using adipose-derived stem cells and PC12 cells. • The cells encounter acceptably low levels of damage in contact with microspheres. - Abstract: The goal of this study was to fabricate and investigate the chitosan coated poly(lactic-co-glycolic acid) (PLGA) microspheres for the development of controlled release magnesium delivery system. PLGA based microspheres are ideal vehicles for many controlled release drug delivery applications. Chitosan is a naturally occurring biodegradable and biocompatible polysaccharide, which can coat the surface of PLGA to alter the release of drugs. Magnesium gluconate (MgG) was encapsulated in the PLGA and PLGA/chitosan microspheres by utilizing the double emulsion solvent evaporation technique for controlled release study. The microspheres were tested with respect to several physicochemical and biological properties, including morphology, chemical structure, chitosan adsorption efficiency, magnesium encapsulation efficiency, in vitro release of magnesium ions, and cellular compatibility using both human adipose-derived stem cells (ASCs) and PC12 cells. Chitosan coated PLGA microspheres can significantly control the release of magnesium ions compared to uncoated PLGA microspheres. Both coated and uncoated microspheres showed good cellular compatibility.

  11. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Jiaqian, E-mail: jiaqian.q@chula.ac.th [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand); Zhang, Xinyu, E-mail: xyzhang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2017-01-15

    Highlights: • ZnO microspheres-rGO nanocomposites were prepared via a solution method. • ZnO microspheres anchored on the rGO sheets is observed using SEM and TEM. • The obtained nanocomposites exhibit good photocatalytic degradation of MB under UV light irradiation. - Abstract: In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h{sup +}) and superoxide radicals (·O{sub 2}{sup −}).

  12. Egg albumin microspheres containing paracetamol for oral administration. II. In vivo investigation.

    Science.gov (United States)

    Torrado, J J; Illum, L; Cadorniga, R; Davis, S S

    1990-01-01

    Egg albumin microspheres containing paracetamol for oral administration were prepared and their in vivo characteristics evaluated. The egg albumin microspheres were able to improve the organoleptic characteristics of paracetamol formulations. The pharmacokinetic characteristics of three different formulations of paracetamol were evaluated in six volunteers. The formulations administered orally were: (1) Paracetamol granulated with lactose (reference), (2) Egg albumin microspheres and (3) Egg albumin microspheres coated with polymethacrylate. The pharmacokinetic characteristics for formulations 1 and 2 were similar but formulation 3 gave significant differences (p less than 0.05) in Ka, Cmax and tmax. No significant differences in relative bioavailability were observed.

  13. Preparation of quantum dots encoded microspheres by electrospray for the detection of biomolecules.

    Science.gov (United States)

    Sun, Lei; Yu, Xiaofang; Sun, Mingda; Wang, Hengguo; Xu, Shufei; Dixon, John D; Wang, Y Andrew; Li, Yaoxian; Yang, Qingbiao; Xu, Xiaoyi

    2011-06-01

    In this paper, a novel method based on the electrospray technique has been developed for preparation of quantum dot (QD)-encoded microspheres for the fist time. By electrospraying the mixture of polymer solution and quantum dots solution (single-color QDs or multi-color QDs), it is accessible to obtain a series of composite microspheres containing the functional nanoparticle. Poly(styrene-acrylate) was utilized as the electrospray polymer materials in order to obtain the microsphere modified with carboxyl group on the surface. Moreover, to test the performance of the QD-encoded microsphere in bioapplication, it is carried out that immunofluorescence analysis between antigens of mouse IgG immobilized on the functional microsphere and FITC labeled antibodies of goat-anti-mouse IgG in experiment. To the best of our knowledge, this is the first report of QD-encoded microspheres prepared by electrospray technology. This technology can carry out the one-pot preparation of different color QD-encoded microspheres with multiple intensities. This technology could be also suitable for encapsulating other optical nanocrystals and magnetic nanoparticles for obtaining multifunctional microspheres. All of the results in this paper show that the fluorescence beads made by electrospray technique can be well applied in multiplex analysis. These works provide a good foundation to accelerate application of preparing microspheres by electrospray technique in practice. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Development of Bioadhesive Microspheres for Oral Bioavailability Enhancement of Berberine Hydrochloride

    Directory of Open Access Journals (Sweden)

    Ye Zhang

    2016-01-01

    Full Text Available The objective of this study was to innovatively prepare chitosan-coated alginate/gelatin BBH loaded microspheres and evaluate their pharmaceutical characteristics and pharmacokinetics. The bioadhesive microspheres were prepared using an emulsification technique. Three batches of microspheres were formed and their stability was evaluated. BBH loaded microspheres were almost spherical with shallow elevation on surfaces. The mean particle size of microspheres was 368.2 μm, drug loading was 3.59±0.01%, and in situ bioadhesion percentage was 91.23%±8.2% and they achieved a sustained release with 71.29% for 8 hours in vitro. Pharmacokinetic studies in rats indicated that the bioavailability of BBH microspheres was enhanced about 1.5-fold as compared with commercial tablets. BBH microspheres exhibited a sustained-release profile over 48 h. Thus, chitosan-coated alginate/gelatin BBH loaded microspheres which combined the advantages of alginate/gelatin microspheres and chitosan may be used as a sustained delivery system for BBH to treat duodenal and benign gastric ulcers.

  15. 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.

  16. A new process for the production of clinical dextran by mixed-culture fermentation of Lipomyces starkeyi and Leuconostoc mesenteroides.

    Science.gov (United States)

    Kim, D; Day, D F

    1994-10-01

    A mixed-culture fermentation system was designed for the production of size-limited dextrans. This process was simpler and more economical than traditional methods. It required the establishment of microbial consortia of Lipomyces starkeyi ATCC 74054 and Leuconostoc mesenteroides ATCC 10830. Controlling initial conditions, growth, and enzyme production by both organisms controlled the product size. In this process, both strains were grown separately and then mixed. Dextran fermentation was then allowed to proceed. At the desired time (and molecular size), the fermentation was harvested. The optimum pH and temperature for production of clinical dextran (75,000 MW) were 5.2 (+/- 0.1) and 28 (+/- 0.5) degrees C, respectively. Varying the ratio of L. mesenteroides to L. starkeyi in the inoculum did not significantly affect either the final cell ratios or dextran production.

  17. Formation of nanoparticles by cooperative inclusion between (S-camptothecin-modified dextrans and β-cyclodextrin polymers

    Directory of Open Access Journals (Sweden)

    Thorbjørn Terndrup Nielsen

    2015-01-01

    Full Text Available Novel (S-camptothecin–dextran polymers were obtained by “click” grafting of azide-modified (S-camptothecin and alkyne-modified dextrans. Two series based on 10 kDa and 70 kDa dextrans were prepared with a degree of substitution of (S-camptothecin between 3.1 and 10.2%. The binding properties with β-cyclodextrin and β-cyclodextrin polymers were measured by isothermal titration calorimetry and fluorescence spectroscopy, showing no binding with β-cyclodextrin but high binding with β-cyclodextrin polymers. In aqueous solution nanoparticles were formed from association between the (S-camptothecin–dextran polymers and the β-cyclodextrin polymers.

  18. Mechanisms of complement activation by dextran-coated superparamagnetic iron oxide (SPIO) nanoworms in mouse versus human serum

    DEFF Research Database (Denmark)

    Banda, Nirmal K; Mehta, Gaurav; Chao, Ying

    2014-01-01

    BACKGROUND: The complement system is a key component of innate immunity implicated in the neutralization and clearance of invading pathogens. Dextran coated superparamagnetic iron oxide (SPIO) nanoparticle is a promising magnetic resonance imaging (MRI) contrast agent. However, dextran SPIO has...... been associated with significant number of complement-related side effects in patients and some agents have been discontinued from clinical use (e.g., Feridex™). In order to improve the safety of these materials, the mechanisms of complement activation by dextran-coated SPIO and the differences between...... mice and humans need to be fully understood. METHODS: 20 kDa dextran coated SPIO nanoworms (SPIO NW) were synthesized using Molday precipitation procedure. In vitro measurements of C3 deposition on SPIO NW using sera genetically deficient for various components of the classical pathway (CP), lectin...

  19. The effects of synthesis method on the physical and chemical properties of dextran coated iron oxide nanoparticles.

    Science.gov (United States)

    Hauser, Anastasia K; Mathias, Ronita; Anderson, Kimberly W; Hilt, J Zach

    2015-06-15

    Iron oxide nanoparticles coated with dextran were synthesized via four variations on the co-precipitation method. The methods ranged from in situ formation of the nanoparticles within the dextran solution to the adsorption of dextran to the nanoparticle surface following nucleation and extensive washing. The timing of the addition of dextran into the reaction mixture was found to greatly influence the physical and chemical properties of the magnetic nanoparticles. Batches of dextran coated iron oxide nanoparticles were synthesized by each method in triplicate, and the nanoparticles were further crosslinked with epichlorohydrin. The properties of the nanoparticles such as size, percentage of dextran coating, stability in solution, crystallinity, and magnetic properties were evaluated. The simultaneous semi-two-step method injected the reducing agent and the dextran solution into the reaction vessel at the same time. This method resulted in the greatest batch-to-batch reproducibility of nanoparticle properties and the least variation in nanoparticles synthesized in the same batch. The two-step method resulted in the greatest variation of the characteristics examined between batches. The one-step method was synthesized with both five grams and one gram of dextran to investigate the effects of solution viscosity on the resulting nanoparticle characteristics. The one-step method with five grams of dextran resulted in nanoparticles with significantly smaller crystal sizes (5.4 ± 1.9 nm) and lower specific adsorption rate (SAR) values (138.4 ± 13.6 W/g) in an alternating magnetic field (58 kA/m, 292 kHz). However, this method resulted in nanoparticles that were very stable in PBS over 12 hours, which is most likely due to the greater dextran coating (60.0 ± 2.7 weight percent). For comparison, the simultaneous semi-two-step method generated nanoparticles 179.2 ± 18.3 nm in diameter (crystal size 12.1 ± 0.2 nm) containing 18.3 ± 1.2 weight percent dextran with a SAR

  20. Investigation of Expandable Polymeric Microspheres for Packaging Applications

    Science.gov (United States)

    2012-06-06

    printing inks , internally pressurized tennis balls, and foaming cable compounds. Microspheres were compounded into high density polyethylene...microspheres), printing  inks   (60‐80%), and tennis balls  and foaming cable filling compounds (over 99%) [2].  According to a literature search, polymer...Density  (g/cm³)  0.96  0.90  Oxygen  Permeability   (cc/m²)  1550‐3100  2325‐3100  Water Vapor  Permeability   (gm/m²)  4.65‐7.75  3.10‐7.75    2.1.2

  1. Quadruple-responsive nanocomposite based on dextran-PMAA-PNIPAM, iron oxide nanoparticles, and gold nanorods.

    Science.gov (United States)

    Feng, Wenqian; Lv, Weipeng; Qi, Junjie; Zhang, Guoliang; Zhang, Fengbao; Fan, Xiaobin

    2012-01-01

    A quadruple-responsive nanocomposite that responds to temperature, pH, magnetic field, and NIR is obtained by incorporating superparamagnetic iron oxide nanoparticles (SPIONs) and gold nanorods (AuNRs) into a dextran-based smart copolymer network. The dual-sensitive copolymer is prepared by sequential RAFT polymerization of methacrylic acid and N-isopropylacrylamide from trithiocarbonate groups linked to dextran in one pot. These functionalized nanocomposites with superior stability can respond to the four stimuli mentioned above well. As evidenced by UV-vis and TEM measurements, the temperature-induced unusual blue-shift in the longitudinal plasmon band is possibly due to the side-to-side assembly of AuNRs. Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Investigating the effective hydrodynamic size of dextran coated iron oxide nanoparticles

    Science.gov (United States)

    Vaishnava, Prem; Gumber, Vikas; Regmi, Rajesh; Black, Correy; Dixit, Ambesh; Naik, Vaman; Sudakar, Chandran; Naik, Ratna; Lawes, Gavin

    2010-04-01

    We report synthesis and functionalization of magnetite nanoparticles by coating with dextran having 5, 15-20, 60-90, and 670 kDa molecular weights. The hydrodynamic radii of the functionalized nanoparticles suspended in water measured by dynamic light scattering technique assuming the bulk value for viscosity, were 91, 100, 106, and 132 nm, respectively. By measuring the ac magnetic loss, we determined the effective sizes to be 105, 113, 122, and 136 nm, respectively. The sizes measured by these techniques are approximately twice as large as expected given the iron oxide nanoparticle size and surfactant molecular chain length, at least for the lower molecular weight dextran. Comparing the results of hydrodynamic sizes studies, we conclude that the effective viscosity for the coated nanoparticles may be different than the bulk viscosity of the carrier liquid.

  3. Quantitation of uveoscleral outflow in normotensive and glaucomatous Beagles by /sup 3/H-labeled dextran

    Energy Technology Data Exchange (ETDEWEB)

    Barrie, K.P.; Gum, G.G.; Samuelson, D.A.; Gelatt, K.N.

    1985-01-01

    In uveoscleral outflow, aqueous humor leaves the anterior chamber and passes caudally through the trabecular meshwork and the sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is then absorbed by choroidal and scleral circulations. Using /sup 3/H-labeled dextran, uveoscleral outflow was quantitated in normotensive and glaucomatous Beagles under general anesthesia. The intrascleral plexus was isolated and /sup 3/H-labeled dextran was injected into the anterior chamber. Intrascleral plexus contents were sampled every 5 minutes over a 30- to 60-minute period. The eyes were enucleated, sectioned, and prepared for scintillation counting. Uveoscleral outflow accounted for 15% and 3% of the total aqueous humor outflow in the normotensive dogs and in the advanced glaucomatous dogs, respectively. In the advanced glaucomatous Beagle, conventional and uveoscleral outflow pathways were reduced and contributed to the etiopathogenesis of glaucoma.

  4. Safety of total dose iron dextran infusion in geriatric patients with chronic kidney disease and iron deficiency anemia.

    Science.gov (United States)

    Dossabhoy, Neville R; Turley, Steven; Gascoyne, Rebecca; Tapolyai, Mihaly; Sulaiman, Karina

    2014-08-01

    There are limited data on total dose infusion (TDI) using iron dextran in geriatric chronic kidney disease (CKD) patients with iron-deficiency anemia (IDA). Our goal was to evaluate the safety of TDI in this setting. We conducted a retrospective chart review spanning a 5 year period (2002-2007), including all patients with CKD and IDA who were treated with iron dextran TDI. Patient demographics were noted, and laboratory values for creatinine, hemoglobin and iron stores were recorded pre- and post-dose. TDI diluted in normal saline was administered intravenously over 4-6 hours after an initial test dose. One hundred fifty-three patients received a total of 250 doses of TDI (mean ± SD=971 ± 175 mg); age was 69 ± 12 years and creatinine 3.3 ± 1.9 mg/dL. All stages of CKD were represented (stage 4 commonest). Hemoglobin and iron stores improved post-TDI (Piron dextran produced 6 AEs (5.45%), whereas 140 doses of low molecular weight (LMW) iron dextran produced 2 AEs (1.43%), a non-significant trend (P=0.1433 by Fishers Exact Test). Iron dextran TDI is relatively safe and effective in correcting IDA in geriatric CKD patients. Fewer AEs were noted with the LMW compared to the HMW product. LMW iron dextran given as TDI can save both cost and time, helping to alleviate issues of non-compliance and patient scheduling.

  5. Optimization of dextran production by Weissella cibaria NITCSK4 using Response Surface Methodology-Genetic Algorithm based technology.

    Science.gov (United States)

    Kanimozhi, J; Moorthy, I Ganesh; Sivashankar, R; Sivasubramanian, V

    2017-10-15

    The most influencing factor on dextran production by Weissella cibaria NITCSK4 were screened using Plackett Burman design at 95% confidence limit with higher value of co-efficient of determination (R(2)) 99.58%. The combined effects of significant factors, namely, sucrose, temperature, dipotassium hydrogen phosphate (K2HPO4) and yeast extract were studied and optimized using Response Surface Methodology (RSM). The input parameters of non-linear models predicted by RSM were subsequently optimized using the genetic algorithm (GA) for obtaining a maximum dextran yield. The maximum yield was obtained with sucrose concentration of 15.78%, yeast extract 1.27%, K2HPO4 1.25%, and at 26°C. The predicted conditions were experimentally validated and 43.79mg/ml of dextran was produced. The dextran yield was 51% higher as compared to unoptimized medium. The molecular weight of resulting dextran produced at 26°C is >2000kDa. The NMR spectroscopic analysis demonstrated that the NITCSK4 produced linear dextran with predominant α (1-6) linkage. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Czech Academy of Sciences Publication Activity Database

    Koubková, Jana; Müller, P.; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, B.; Horák, Daniel

    2014-01-01

    Roč. 31, č. 5 (2014), s. 482-491 ISSN 1871-6784 R&D Projects: GA ČR GCP207/12/J013; GA MŠk 7E12053 EU Projects: European Commission(XE) 246513 - NADINE Institutional support: RVO:61389013 Keywords : glycidyl methacrylate * microspheres * protein p53 Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.898, year: 2014

  7. Asymmetrical two-atom entanglement in a coated microsphere

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-25

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

  8. MAGNETIC MICROSPHERES AS A TARGETED DRUG DELIVERY SYSTEM : A REVIEW

    OpenAIRE

    TARUN PATEL; SHAILESH SONI; BHAUMIK THAKAR; VIKRAM PANDYA; PRAFUL BHARADIA

    2012-01-01

    The in-vivo targeting of tumors with magnetic microspheres is currently realized through the applicationof external non-uniform magnetic fields generated by rare-earth permanent magnets or electromagnets.This technique can be applied to magnetically targeted cancer therapy, magnetic embolization therapywith magnetic particles that contain anticancer agent, such as chemotherapeutic drugs or therapeuticradioisotopes. Drug targeting is one way of local or regional antitumor treatment. Magnetical...

  9. pH-Sensitive Mebeverine Microspheres for Colon Delivery

    OpenAIRE

    Dandagi P; Mastiholimath V; Gadad A; Kulkarni A; Konnur B

    2009-01-01

    Mebeverine hydrochloride is known to suffer from extensive first pass effect. In an attempt to improve its oral bioavailability and possibility to restrict its absorption only to the colon, mebeverine microspheres were prepared by emulsion solvent evaporation method. Four formulations were prepared with varying drug and polymer ratio. These formulations were subjected to various evaluation parameters like percent practical yield, entrapment efficiency, particle size, in vitro drug release, in...

  10. Study of heating effect and acoustic properties of dextran stabilized magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Jozefczak, Arkadiusz [Faculty of Physics, Institute of Acoustics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland)]. E-mail: aras@amu.edu.pl; Skumiel, Andrzej [Faculty of Physics, Institute of Acoustics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland)

    2007-04-15

    This paper presents acoustic properties of water-based biocompatible fluids in which magnetite particles (Fe{sub 3}O{sub 4}) were coated with two layers of surfactants: sodium oleate and dextran. The attenuation coefficient of ultrasonic wave measurements shows good structural stability of the fluid under the influence of a magnetic field. Hyperthermic tests proved that the magnetic fluid is suitable for therapeutic use as an agent which can release thermal energy (hyperthermia)

  11. Development of radiolabeled mannose-dextran conjugates for sentinel lymph node detection; Desenvolvimento de conjugados de dextran manose radiomarcados para deteccao de linfonodo sentinela

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Nunez, Eutimio Gustavo

    2011-07-01

    Early diagnosis of tumors and metastasis is the current cornerstone in public health policies directed towards the fights against cancer. In breast cancer and melanoma, the sentinel lymph node biopsy has been widely used for diagnoses of metastasis. The minor impact in patient of this technique compared with total nodes dissection and the accurate definition of therapeutic strategies have powered its spreading. The aim of this work was the development of radiolabeled dextran-mannose conjugates for diagnosis using the stable technetium core [{sup 99m}Tc(CO)3]{sup +}. Cysteine, a trident ligand, was attached to the conjugates backbone, as a chelate for {sup 99m}Tc labeling. Radiolabeling conditions established for all products considered in this study showed high radiochemical purities (> 90%) and specific activities (>59,9 MBq/nmol) as well and high stability obtained through in vitro tests. The lymphatic node uptake increased significantly (4-folds) when mannose units were added to the conjugates compared with those without this monosaccharide. The radiolabeled cysteine-mannose-dextran conjugate with 30 kDa ({sup 99m}Tc - DCM2) showed the best performance at different injected activities among the studied tracers. Concentrations of this radio complex higher than 1 M demonstrated an improvement of lymph node uptakes. Comparisons of {sup 99m}Tc - DCM2 performance with commercial radiopharmaceuticals in Brazil market for lymph node detection showed its upper profile. (author)

  12. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Directory of Open Access Journals (Sweden)

    Ratthaphol Charlermroj

    Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  13. Magnetic microspheres as magical novel drug delivery system: A review

    Directory of Open Access Journals (Sweden)

    Satinder Kakar

    2013-01-01

    Full Text Available Magnetic microspheres hold great promise for reaching the goal of controlled and site specific drug delivery. Magnetic microspheres as an alternative to traditional radiation methods which uses highly penetrating radiations that is absorbed throughout the body. Its use is limited by toxicity and side effects. Now days, several targeted treatment systems including magnetic field, electric field, ultrasound, temperature, UV light and mechanical force are being used in many disease treatments (e.g. cancer, nerve damage, heart and artery, anti-diabetic, eye and other medical treatments. Among them, the magnetic targeted drug delivery system is one of the most attractive and promising strategy for delivering the drug to the specified site. Magnetically controlled drug targeting is one of the various possible ways of drug targeting. This technology is based on binding establish anticancer drug with ferrofluid that concentrate the drug in the area of interest (tumor site by means of magnetic fields. There has been keen interest in the development of a magnetically target drug delivery system. These drug delivery systems aim to deliver the drug at a rate directed by the needs of the body during the period of treatment, and target the activity entity to the site of action. Magnetic microspheres were developed to overcome two major problems encountered in drug targeting namely: RES clearance and target site specificity.

  14. Mucoadhesive microspheres: A novel approach to increase gastroretention

    Directory of Open Access Journals (Sweden)

    Alka Lohani

    2012-01-01

    Full Text Available The aim of this study is to review the advantages of mucoadhesive microspheres, mechanisms, and theories involved in mucoadhesion, factors that affect the mucoadhesion and polymers in mucoadhesive drug delivery systems. Gastroretentive drug delivery systems are those which are retained in the stomach for a longer period of time and thereby improve the bioavailability of drugs. Mucoadhesion is a topic of current interest in the design of drug delivery systems. Mucoadhesion is currently explained by six theories: electronic, adsorption, wetting, mechanical, diffusion, and fracture. Microspheres constitute an important part of these particulate drug delivery systems by virtue of their small size and efficient carrier capacity, but coupling of bioadhesive properties to these microspheres has additional advantages such as prolong residence time of the dosage form at the site of absorption and intimate contact of the dosage form with the underline absorption surface contributed to improved therapeutic performance of the drug or improved bioavailability of drug, reduced dosing frequency, and improved patience compliance.

  15. pH-Sensitive Mebeverine Microspheres for Colon Delivery.

    Science.gov (United States)

    Dandagi, P M; Mastiholimath, V S; Gadad, A P; Kulkarni, A R; Konnur, B K

    2009-07-01

    Mebeverine hydrochloride is known to suffer from extensive first pass effect. In an attempt to improve its oral bioavailability and possibility to restrict its absorption only to the colon, mebeverine microspheres were prepared by emulsion solvent evaporation method. Four formulations were prepared with varying drug and polymer ratio. These formulations were subjected to various evaluation parameters like percent practical yield, entrapment efficiency, particle size, in vitro drug release, in vivo activity. Practical yield of the microspheres was up to 89.59% with encapsulation efficiency up to 79.4%. Scanning electron microscopy confirmed that the microsphere structures were smooth, spherical, and discrete and the particles were of the size range 200 to 300 mum. In vitro release of the drug showed biphasic release pattern with non-Fickian diffusion release in 12 h. On the basis of drug content, particle size, in vitro release and in vivo studies, formulation F-3 was found to be optimal. Antiirritable bowel syndrome activity was performed in colorectal distention in rat, which is a model for constipation-induced irritable bowel syndrome. The formulations F-2 and F-3 showed significant effect in fecal output when compared to the control as well as the marketed preparation in the constipation-induced irritable bowel syndrome in rats.

  16. Power output and efficiency of beta-emitting microspheres

    Science.gov (United States)

    Cheneler, David; Ward, Michael

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire's theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer.

  17. Toxicity, toxicokinetics and biodistribution of dextran stabilized Iron oxide Nanoparticles for biomedical applications.

    Science.gov (United States)

    Remya, N S; Syama, S; Sabareeswaran, A; Mohanan, P V

    2016-09-10

    Advancement in the field of nanoscience and technology has alarmingly raised the call for comprehending the potential health effects caused by deliberate or unintentional exposure to nanoparticles. Iron oxide magnetic nanoparticles have an increasing number of biomedical applications and hence a complete toxicological profile of the nanomaterial is therefore a mandatory requirement prior to its intended usage to ensure safety and to minimize potential health hazards upon its exposure. The present study elucidates the toxicity of in house synthesized Dextran stabilized iron oxide nanoparticles (DINP) in a regulatory perspective through various routes of exposure, its associated molecular, immune, genotoxic, carcinogenic effects and bio distribution profile. Synthesized ferrite nanomaterials were successfully coated with dextran (dextran helps in improvising particle stability in biological environments. The nanoparticles do not seem to induce oxidative stress mediated toxicological effects, nor altered physiological process or behavior changes or visible pathological lesions. Furthermore no anticipated health hazards are likely to be associated with the use of DINP and could be concluded that the synthesized DINP is nontoxic/safe to be used for biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Peripheral iron dextran induced degeneration of dopaminergic neurons in rat substantia nigra.

    Science.gov (United States)

    Jiang, Hong; Song, Ning; Wang, Jun; Ren, Li-Ying; Xie, Jun-Xia

    2007-07-01

    Iron accumulation is considered to be involved in the pathogenesis of Parkinson's disease. To demonstrate the relationship between peripheral iron overload and dopaminergic neuron loss in rat substantia nigra (SN), in the present study we used fast cyclic voltammetry, tyrosine hydroxylase (TH) immunohistochemistry, Perls' iron staining, and high performance liquid chromatography-electrochemical detection to study the degeneration of dopaminergic neurons and increased iron content in the SN of iron dextran overloaded animals. The findings showed that peripheral iron dextran overload increased the iron staining positive cells and reduced the number of TH-immunoreactive neurons in the SN. As a result, dopamine release and content, as well as its metabolites contents were decreased in caudate putamen. Even more dramatic changes were found in chronic overload group. These results suggest that peripheral iron dextran can increase the iron level in the SN, where excessive iron causes the degeneration of dopaminergic neurons. The chronic iron overload may be more destructive to dopaminergic neurons than the acute iron overload.

  19. Use of iron sucrose in dialysis patients sensitive to iron dextran

    Directory of Open Access Journals (Sweden)

    Haddad Ayham

    2009-01-01

    Full Text Available This study aimed to assess the safety and efficacy of iron sucrose in hemodialysis (HD patients with documented hypersensitivity reactions to iron dextran. Of 205 HD patients who received low molecular weight iron dextran, 15 (7.3% patients developed documented hypersensitivity reactions. The patients were treated with iron sucrose (100 mg administered as an intravenous push over 5-10 minutes once a week for 8 weeks. Complete blood count, serum iron, serum ferritin, and parathyroid hormone were measured at the beginning and at the end of the study (except parathyroid hormone. All patients received subcutaneous erythropoietin at a constant dose of 5000 IU twice weekly unless a change was required. All the patients completed the study period and none of them developed hypersensitivity reactions to iron sucrose. The mean hematocrit increased from 23.8% to 32.27% (p < 0.0001, the mean serum ferritin from 185 ng/mL to 599 ng/mL (p < 0.0001, and the mean serum iron from 29.3 ng/dL to 76.8 ng/dL (p = 0.01. We conclude that iron sucrose is safe and effective in HD patients with documented hypersensitivity reactions to low molecular weight iron dextran.

  20. Size-controlled synthesis of dextran sulfate coated iron oxide nanoparticles for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jarrett, Benjamin R; Frendo, Michele; Vogan, Jacob; Louie, Angelique Y [Department of Biomedical Engineering, University of California, Davis, CA 95616 (United States)

    2007-01-24

    In the generation of nanoparticles for biological applications, the control over synthetic parameters influencing the particles' physicochemical properties are of great interest due to the strong influence of particle size and surface properties on cellular uptake and biodistribution. We have synthesized dextran sulfate coated particles and systematically evaluated synthetic parameters that may influence the properties of these nanoparticles as potential magnetic resonance (MR) contrast agents. The amount of base, polysaccharide content, ratio of iron salts, and reaction time were optimized to yield approximately 30 nm particles as determined by dynamic light scattering with good MR properties (r{sub 1} = 14.46 mM{sup -1} s{sup -1} and r{sub 2} = 72.55 mM{sup -1} s{sup -1}) and in good yield (50%). Particle sizes and relaxivities are compared with clinically available dextran coated particles and the resulting physical properties of the dextran sulfate coated particles show these particles could be used as potential MR contrast agents for cardiovascular imaging.

  1. Differential inhibition of polymorphonuclear leukocyte recruitment in vivo by dextran sulphate and fucoidan

    Directory of Open Access Journals (Sweden)

    N. Van Osselaer

    1996-01-01

    Full Text Available The selectin-mediated rolling of leukocytes along the endothelial cells is a prerequisite step followed by firm adhesion and extravasation into the inflamed tissue. This initial contact can be suppressed by sulphated polysaccharides. We have studied the effect of sulphated polysaccharides on the ultimate polymorphonuclear leukocyte (PMN recruitment and plasma leakage in rabbit skin in response to intradermal injection of various inflammatory mediators. PMN infiltration evoked by various PMN chemoattractants (FMLP, C5a desArg, LTB4 and IL-8 was significantly inhibited after intravenous injection of dextran sulphate (25 mg/kg, heparin (2 × 90 mg/kg or fucoidan (1 mg/kg. PMN-dependent plasma leakage was equally well reduced by the different sulphated polymers. Vascular permeability induced by histamine or thrombin acting via a PMN-independent mechanism was not reduced. Fucoidan was the only polysaccharide able to suppress IL-1-induced PMN infiltration for 60–70%. Local administration of dextran sulphate had no effect on PMN-dependent plasma leakage. Differential inhibition of PMN recruitment was determined after injection of dextran sulphate or fucoidan depending on the type of insult. Therefore, these results suggest that different adhesion pathways are utilized during PMN recruitment in vivo in response to chemoattractants and IL-1.

  2. Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinking.

    Science.gov (United States)

    Rechichi, Miguel; Mazzotta, Cosimo; Daya, Sheraz; Mencucci, Rita; Lanza, Michele; Meduri, Alessandro

    2016-10-01

    To assess intraoperative corneal pachymetry in patients undergoing accelerated corneal collagen crosslinking with a dextran-free riboflavin solution. Prospective, non-comparative, multicenter interventional study. Thirty patients with progressive keratoconus were enrolled in the study from the Siena Crosslinking Center™ in Siena, Italy and the Eye Center in Catanzaro, Italy. The mean age was 26.9 ± 6.5 years. Patients underwent pulsed light accelerated crosslinking (PL-ACXL) by KXL I UV-A source (Avedro Inc., Waltham, MS, USA) with 8 min (1 s on/1 s off) of UV-A exposure, 30 mW/cm(2) and an energy dose of 7.2 J/cm(2). Corneal stroma was soaked with a dextran-free 0.1% riboflavin solution plus hydroxyl-propyl methylcellulose (HPMC) (VibeX Rapid, Avedro). Intraoperative corneal thickness was preoperatively (PRE-OP) evaluated by corneal optical coherence tomography (iVUE Optovue Inc., Fremont, CA, USA) after epithelium removal (EPI-R), after 10 min of riboflavin soaking (RS) and after UV-A irradiation (IR). Statistical analysis was conducted using a Wilcoxon test and SPSS v16.0. A p-value of collagen crosslinking by using dextran free HPMC 0.1% riboflavin solution.

  3. Magnetic retardance and magnetic heating in dextran-citrate coated ferrofluids

    Directory of Open Access Journals (Sweden)

    Jing-Fung Lin

    2017-02-01

    Full Text Available The Fe3O4 magnetic nanoparticles (MNPs coated by citrate and dextran prepared by the co-precipitation method was described. Influence induced by the mass variation of coating dextran was investigated. Magneto-optical birefringence of biocompatible dextran-citrate (DC coated ferrofluids (FFs was obtained by the Stokes polarimeter. Next, uniform design method was used to find the DC coated FF with high retardance and low dichroism. Retardance of the optimized A9 sample with 1 g/ml was measured as 56.7898° (dichroism was 0.3716 under 64.5 mT. Further, magnetic heating effect in alternating magnetic field was investigated. When the concentrations of A9 were of 2 mg/ml and 50 mg/ml, under the external alternating magnetic field with applied apparent current of 210 A, after heating 5 s the temperature of the DC coated FFs was greater than 47 °C, respectively, reached the requirements for the magnetic inductive heating treatment of cancer tumor. The potential of DC coated FFs in hyperthermia was highly evaluated.

  4. Development of in vitro-in vivo correlation of parenteral naltrexone loaded polymeric microspheres.

    Science.gov (United States)

    Andhariya, Janki V; Shen, Jie; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J

    2017-06-10

    Establishment of in vitro-in vivo correlations (IVIVCs) for parenteral polymeric microspheres has been very challenging, due to their complex multiphase release characteristics (which is affected by the nature of the drug) as well as the lack of compendial in vitro release testing methods. Previously, a Level A correlation has been established and validated for polymeric microspheres containing risperidone (a practically water insoluble small molecule drug). The objectives of the present study were: 1) to investigate whether a Level A IVIVC can be established for polymeric microspheres containing another small molecule drug with different solubility profiles compared to risperidone; and 2) to determine whether release characteristic differences (bi-phasic vs tri-phasic) between microspheres can affect the development and predictability of IVIVCs. Naltrexone was chosen as the model drug. Three compositionally equivalent formulations of naltrexone microspheres with different release characteristics were prepared using different manufacturing processes. The critical physicochemical properties (such as drug loading, particle size, porosity, and morphology) as well as the in vitro release characteristics of the prepared naltrexone microspheres and the reference-listed drug (Vivitrol®) were determined. The pharmacokinetics of the naltrexone microspheres were investigated using a rabbit model. The obtained pharmacokinetic profiles were deconvoluted using the Loo-Riegelman method, and compared with the in vitro release profiles of the naltrexone microspheres obtained using USP apparatus 4. Level A IVIVCs were established and validated for predictability. The results demonstrated that the developed USP 4 method was capable of detecting manufacturing process related performance changes, and most importantly, predicting the in vivo performance of naltrexone microspheres in the investigated animal model. A critical difference between naltrexone and risperidone loaded

  5. Mobilization of microspheres from a fractured soil during intermittent infiltration events

    Science.gov (United States)

    Mohanty, Sanjay; Bulicek, Mark; Metge, David W.; Harvey, Ronald W.; Ryan, Joseph N.; Boehm, Alexandria B.

    2015-01-01

    Pathogens or biocolloids mobilized in the vadose zone may consequently contaminate groundwater. We found that microspheres were mobilized from a fractured soil during intermittent rainfall and the mobilization was greater when the microsphere size was larger and when the soil had greater water permeability.The vadose zone filters pathogenic microbes from infiltrating water and consequently protects the groundwater from possible contamination. In some cases, however, the deposited microbes may be mobilized during rainfall and migrate into the groundwater. We examined the mobilization of microspheres, surrogates for microbes, in an intact core of a fractured soil by intermittent simulated rainfall. Fluorescent polystyrene microspheres of two sizes (0.5 and 1.8 mm) and Br− were first applied to the core to deposit the microspheres, and then the core was subjected to three intermittent infiltration events to mobilize the deposited microspheres. Collecting effluent samples through a 19-port sampler at the base of the core, we found that water flowed through only five ports, and the flow rates varied among the ports by a factor of 12. These results suggest that flow paths leading to the ports had different permeabilities, partly due to macropores. Although 40 to 69% of injected microspheres were retained in the core during their application, 12 to 30% of the retained microspheres were mobilized during three intermittent infiltration events. The extent of microsphere mobilization was greater in flow paths with greater permeability, which indicates that macropores could enhance colloid mobilization during intermittent infiltration events. In all ports, the 1.8-mm microspheres were mobilized to a greater extent than the 0.5-mm microspheres, suggesting that larger colloids are more likely to mobilize. These results are useful in assessing the potential of pathogen mobilization and colloid-facilitated transport of contaminants in the subsurface under natural infiltration

  6. Liraglutide-loaded poly(lactic-co-glycolic acid) microspheres: Preparation and in vivo evaluation.

    Science.gov (United States)

    Wu, Junzi; Williams, Gareth R; Branford-White, Christopher; Li, Heyu; Li, Yan; Zhu, Li-Min

    2016-09-20

    In this work, we sought to generate sustained-release injectable microspheres loaded with the GLP-1 analogue liraglutide. Using water-in-oil-in-water double emulsion methods, poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with liraglutide were prepared. The microspheres gave sustained drug release over 30days, with cumulative release of up to 90% reached in vitro. The microspheres were further studied in a rat model of diabetes, and their performance compared with a group given daily liraglutide injections. Reduced blood sugar levels were seen in the microsphere treatment groups, with the results being similar to those obtained with conventional injections between 10 and 25days after the commencement of treatment. After 5 and 30days of treatment, the microspheres seem a little slower to act than the injections. The pathology of the rats' spleen, heart, kidney and lungs was probed after the 30-day treatment period, and the results indicated that the microspheres were safe and had beneficial effects on the liver, reducing the occurrence of fatty deposits seen in untreated diabetic rats. Moreover, in terms of liver, renal and cardiac functions, and blood lipid and antioxidant levels, the microspheres were as effective as the injections. The expression of several proteases linked to the metabolism of aliphatic acids and homocysteine was promoted by the microsphere formulations. Inflammatory markers in the microsphere treatment groups were somewhat higher than the injection group, however. The liraglutide/PLGA microspheres prepared in this work are overall shown to be efficacious in a rat model of diabetes, and we thus believe they have strong potential for clinical use. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  7. 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.

  8. Titania coated hollow glass microspheres for environmental applications

    Science.gov (United States)

    Koopman, Mark C.

    The potential applicability of titania coated hollow glass microspheres (HGMs) to the photocatalytic degradation of microbiological and organic chemical water pollutants could have dramatic positive effects on improving the quality of industrial wastewaters that empty into rivers and streams, as well as potential use in economically improving the quality of drinking water. Heterogeneous photocatalysis using titania has been extensively studied since the 1990's because of its non-toxic nature, its high quantum yield of electrons and photo-holes, and its ability to use ambient solar radiation as a power source. Although titania embodies extraordinarily attractive properties for a range of environmental applications, a viable substrate or method of using the material effectively has not been recognized. HGMs are particularly attractive as a support for titania because of their low density and high surface area to volume ratio, but details of how they react to imposed loading, wear, and impact have not been addressed, nor have materials engineering analyses that could maximize their utility been made. In this study we have examined the microstructure, morphology and micro-compression properties of two types of titania coated hollow microspheres, a commercially produced HGM and cenospheres, a derivative of fly ash. Comparisons of uncoated and titania coated hollow microspheres showed improved failure loads and facture energies for the titania coated materials over the uncoated hollow microspheres. Also, the relationship between failure load and hollow microsphere diameter was characterized and the function employed to explain part of the gain in average failure load for the HGMs. Microscopic examination of titania coated HGMs that were subjected to various turbulent conditions, as well as intentional fracture, indicated good interfacial integrity, which supports the viability of both types of HGMs for potential applications. The photocatalytic reactivity of the titania

  9. Mechanism of Introduction of Exogenous Genes into Cultured Cells Using DEAE-Dextran-MMA Graft Copolymer as Non-Viral Gene Carrier

    OpenAIRE

    Yasuhiko Onishi; Tomohiko Takasaki; Naoji Kubota; Jun Yoshida; Masaaki Mizuno; Junko Higashihara; Masayasu Onishi; Yuki Eshita

    2009-01-01

    Comparative investigations were carried out regarding the efficiency of introduction of exogenous genes into cultured cells using a cationic polysaccharide DEAE-dextran-MMA (methyl methacrylate ester) graft copolymer (2-diethylaminoethyl-dextran-methyl methacrylate graft copolymer; DDMC) as a nonviral carrier for gene introduction. The results confirmed that the gene introduction efficiency was improved with DDMC relative to DEAE-dextran. Comparative investigations were carried out using vari...

  10. On-Chip Facile Preparation of Monodisperse Resorcinol Formaldehyde (RF Resin Microspheres

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2018-01-01

    Full Text Available Monodisperse resorcinol formaldehyde resin (RF microspheres are an important polymeric material because of their rich surface functional group and uniform structural characteristics and have been increasingly applied as an electrode material, catalyst support, absorbent, and carbon microsphere precursor. The polymerization conditions, such as the gelation/solidification temperature and the residence time, can largely influence the physical properties and the formation of the 3D polymeric network of the RF microspheres as well as the carbon microspheres. However, few studies have reported on the complexity of the gelation and solidification processes of resol. In this work, we developed a new RF microsphere preparation device that contains three units: a droplet generation unit, a curing unit, and a collection unit. In this system, we controlled the gelation and solidification processes of the resol and observed its curing behavior, which helped us to uncover the curing mechanism of resol. Finally, we obtained the optimized polymerization parameters, obtaining uniform RF microspheres with a variation coefficient of 4.94%. The prepared porous RF microspheres presented a high absorption ability, reaching ~90% at 10 min. Thus, our method demonstrated the practicality of on-chip monodisperse microspheres synthesis. The product was useful in drug delivery and adsorbing large poisonous molecules.

  11. Preparation of porous LaFeO{sub 3} microspheres and their gas-sensing property

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hongxia; Xue, Cheng; Song, Peng, E-mail: mse_songp@ujn.edu.cn; Li, Jia; Wang, Qi

    2015-05-15

    Graphical abstract: - Highlights: • Porous LaFeO{sub 3} microspheres have been successfully synthesized by a convenient and effective hydrothermal method. • The synthesis method has the advantages of controllable fabrication, simple equipment and no additional template. • The mechanism for the formation of porous LaFeO{sub 3} microspheres has been explained in accordance with the Ostwald ripening process. • The as-prepared porous LaFeO{sub 3} microspheres exhibited potential applications in monitoring acetone gas. - Abstract: Porous micro-/nanostructures are of great interest in many current and emerging areas of technology. In this paper, porous microspheres composed of LaFeO{sub 3} nanoparticles were prepared by a convenient and effective method. The obtained microspheres have been structurally characterized by X-ray diffraction analysis (XRD), which confirms the single crystalline orthorhombic structure. By using scanning electron microscopy (SEM), it can be seen that porous LaFeO{sub 3} microspheres with rough surface were assembled from a large amount of interconnected nanoparticles. And transmission electron microscopy (TEM) image has also confirmed their porous feature. A subsequent plausible formation mechanism of porous LaFeO{sub 3} microspheres has been explained in accordance with the Ostwald ripening process. Moreover, gas sensing investigation showed that the sensor based on porous LaFeO{sub 3} microspheres exhibited potential applications in monitoring acetone gas due to their unique morphology and porous structure.

  12. Size matters: effects of PLGA-microsphere size in injectable CPC/PLGA on bone formation

    NARCIS (Netherlands)

    Liao, H.; Lanao, R.P.; Beucken, J.J.J.P van den; Zhou, N.; Both, S.K.; Wolke, J.G.C.; Jansen, J.A.

    2016-01-01

    The aim of this study was to evaluate the effect of PLGA microsphere dimensions on bone formation after injection of calcium phosphate cement (CPC)/PLGA in a guinea pig tibial intramedullarly model. To this end, injectable CPC/PLGA formulations were prepared using PLGA microspheres with either a

  13. Stereolithography fabrication and characterization of syntactic foams containing hollow glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Roques-Carmes, T; Gigante, A; Corbel, S [Departement de Chimie Physique des Reactions, Nancy-Universite 1 (France); Marchal, Ph [Centre de Genie Chimique des Milieux Rheologiquement Complexes, Nancy-Universite (France)

    2009-04-30

    This review presents the stereolithography fabrication of epoxy and acrylate syntactic foams based on hollow glass microspheres. Physicochemical analysis has been performed on the fabricated 3D syntactic foam items containing different amounts of microspheres. The surface free energies, light transmittance, density of the syntactic foams were investigated. Criteria for the choice of a polymeric binder are discussed.

  14. ADRIAMYCIN-LOADED ALBUMIN-HEPARIN CONJUGATE MICROSPHERES FOR INTRAPERITONEAL CHEMOTHERAPY

    NARCIS (Netherlands)

    CREMERS, HFM; SEYMOUR, LW; LAM, K; LOS, G; KWON, G; BAE, YH; KIM, SW; FEIJEN, J

    1994-01-01

    Adriamycin-loaded albumin-heparin conjugate microspheres (ADR-AHCMS) were evaluated as possible intraperitoneal (i.p.) delivery systems for site-specific cytotoxic action. The biocompatibility of the microspheres after intraperitoneal injection was tested first. 1 day after i.p. administration of

  15. Adriamycin-loaded albumin-heparin conjugate microspheres for intraperitoneal chemotherapy

    NARCIS (Netherlands)

    Cremers, Harry; Cremers, H.F.M.; Seymour, L.W.; Lam, K.; Los, G.; van Vugt, M.; Kwon, G.; Bae, Y.H.; Kim, S.W.; Feijen, Jan

    1994-01-01

    Adriamycin-loaded albumin-heparin conjugate microspheres (ADR-AHCMS) were evaluated as possible intraperitoneal (i.p.) delivery systems for site-specific cytotoxic action. The biocompatibility of the microspheres after intraperitoneal injection was tested first. 1 day after i.p. administration of

  16. Effects of formulation variables on Nifedipine microspheres prepared by solvent evaporation technique

    Directory of Open Access Journals (Sweden)

    "Dinarvand R

    2001-07-01

    Full Text Available Preparation and characterization of nifedipine microspheres using ethylcellulose as matrix polymer is described. Nifedipine microspheres were prepared by solvent evaporation technique. The influence of different parameters such as the effect of the concentration of internal and external phases, the amount of drug and the rate of stirring of the medium on the size distribution of microspheres were studied. The effect of drug/polymer ratio and mean particle size on the drug release pattern were also evaluated. Drug release from nifedipine microspheres was studied in a medium, which simulated the change in pH of the pathway of the microspheres from stomach to intestine. It was found that with increase in the concentration of the internal phase, the size of microspheres became larger. Increasing the amount of polyvinyl alcohol in the external phase reduced the size of microspheres. Dissolution was found to be inversely related to the pH, in a way that drug release decreased at higher pH: Drug release from microspheres with small mean particle size was faster than those with large mesh particle size and followed Higuchi model of kinetics.

  17. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NARCIS (Netherlands)

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

    2012-01-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array

  18. 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

  19. Spatial refractive index sensor using whispering gallery modes in an optically trapped microsphere

    NARCIS (Netherlands)

    Zijlstra, P.; Zijlstra, Peter; van der Molen, K.L.; Mosk, Allard

    2007-01-01

    The authors propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. Using the dye embedded in the microsphere as an internal broadband excitation source the authors eliminated the need for a tunable excitation

  20. Kinetics of piroxicam release from low-methylated pectin/zein hydrogel microspheres

    Science.gov (United States)

    The kinetics of a model drug (piroxicam) release from pectin/zein hydrogel microspheres was studied under conditions simulating the gastrointestinal tract. It is established that the rate-limiting step in the release mechanism is drug diffusion out of the microspheres rather than its dissolution. ...

  1. 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.

  2. Effects of gamma-irradiation on PLGA microspheres loaded with thienorphine.

    Science.gov (United States)

    Yang, Yang; Gao, Yongliang; Mei, Xingguo

    2011-09-01

    Ionizing radiation can be used as a drug sterilization technique, provided that the drug itself is not modified and that no toxic products are produced; moreover, if the irradiated product is a drug delivery system, its drug release characteristics must not be significantly altered by radiation. The aim of this work was to study the effects of sterilization by ionizing radiation on PLGA microspheres, containing thienorphine. Thienorphine PLGA microspheres were prepared by the O/W solvent evaporation method and characterized by HPLC, SEM and laser particle size analysis. Our experimental results showed that gamma-rays did not alter the drug content, and did not modify the kinetics of drug release from microspheres. Moreover, no significant changes in the shape and in the size distribution of microspheres were found after irradiation. In conclusion, the sterilization method is adequate because microspheres not underwent any change after exposition to gamma-irradiation.

  3. Invertase immobilization by adsorption on polymer microspheres studied by radioiodination technique

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Alvaro A.A. de [Universidade Federal de Itajuba, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Fisica e Quimica]. E-mail: alencar@unifei.edu.br; Pontin, Luiz F. [Universidade Federal de Itajuba, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Matematica e Computacao]. E-mail: pontin@unifei.edu.br; Higa, Olga Z.; Ribela, Maria Tereza C.P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Biologia Molecular]. E-mail: ozahiga@ipen.br; Tomotani, Ester J.; Vitolo, Michele [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Tecnologia Bioquimico-Farmaceutica]. E-mail: michenzi@usp.br

    2005-07-01

    In this paper, we report the study of the diffusion behavior of invertase onto polystyrene-divinylbenzene (PS-DVB) microspheres. To detect the surface concentration of protein adsorbed on the microspheres, the chloramine-T method was used to label invertase and has been applied to the study of protein sorption properties on the microspheres. The sorption isotherms and the diffusion coefficient (D{sub f}) were computed from experimental results and the concentration of bound invertase was determined in terms of the Fick's law. The Hill equation was applied to the data and the binding capacity of the microspheres were estimated. The results of adsorption show that the radiolabelling invertase method are efficacious at the protein surface concentration detection and can be used to investigate the enzyme immobilization by sorption properties of polymer microspheres. (author)

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

    Science.gov (United States)

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

    2013-08-01

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

  5. Formulation and evalution of montelukast sodium - chitosan based spray dried microspheres for pulmonary drug delivery.

    Science.gov (United States)

    Panchal, Rushi; Patel, Harsha; Patel, Vishnu; Joshi, Pratik; Parikh, Ankit

    2012-03-01

    The objective of present work was to prepare microspheres of montelukast sodium using a natural polymer- chitosan by spray drying method by using glutaraldehyde as a cross linking agent. The microspheres were characterized for size, shape, dissolution, swelling and mucoadhesion. It was observed that, all microspheres were spherical in shape with narrow size distribution. Microspheres had mean particle size of 7-12 μm, with % encapsulation efficiency of 78-86%. The % yield was 32-49% and drug load was 48-53%. With the increase in proportion of chitosan in formulation mucoadhesive strength was increase and also increased in particle size of microspheres. As the drug:polymer ratio increase drug loading was increase and % encapsulation efficiency was also increase.

  6. Nasal administration of heparin-loaded microspheres based on poly(lactic acid).

    Science.gov (United States)

    Yildiz, Ayca; Okyar, Alper; Baktir, Gül; Araman, Ahmet; Ozsoy, Yildiz

    2005-01-01

    In this study, heparin-loaded microspheres having smooth surface and small particle size were designed in order to provide the absorption of heparin through nasal mucosa. For this purpose, microspheres at different polymer/drug ratios (1:10, 1:2.5 and 1:1) and at different concentrations of polyvinyl alcohol, emulsifying agent (1.5% and 2.5% w/v) were prepared by solvent evaporation method with poly(lactic acid). The microspheres were for evaluated shape and surface properties, particle size, production yield, encapsulation efficiency and in vitro drug release. Based on the in vitro data, selected microspheres were applied by nasal route to Wistar albino rats. According to in vivo studies, heparin-loaded microspheres may be used by nasal route as an alternative to parenteral route.

  7. Synthesis of poly(vinyl acetate-methyl methacrylate) copolymer microspheres using suspension polymerization.

    Science.gov (United States)

    Islam, Md Shahidul; Yeum, Jeong Hyun; Das, Ajoy Kumar

    2012-02-15

    Poly(vinyl acetate-methyl methacrylate) (VAc-MMA) copolymer microspheres were prepared using suspension polymerization at low temperature initiated with 2,2'-azobis(2,4-dimethyl valeronitrile) (ADMVN). The poly(VAc-MMA) copolymer microspheres can be used over a large area where homopolymers, polyvinyl acetate (PVAc) and methyl methacrylate (PMMA) microspheres are capable of being put to use. The prepared microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Obtained copolymer microspheres which have 200 μm average diameter and higher thermal stability than those of homopolymer. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  8. Preparation of porous LaFeO3 microspheres and their gas-sensing property

    Science.gov (United States)

    Xiao, Hongxia; Xue, Cheng; Song, Peng; Li, Jia; Wang, Qi

    2015-05-01

    Porous micro-/nanostructures are of great interest in many current and emerging areas of technology. In this paper, porous microspheres composed of LaFeO3 nanoparticles were prepared by a convenient and effective method. The obtained microspheres have been structurally characterized by X-ray diffraction analysis (XRD), which confirms the single crystalline orthorhombic structure. By using scanning electron microscopy (SEM), it can be seen that porous LaFeO3 microspheres with rough surface were assembled from a large amount of interconnected nanoparticles. And transmission electron microscopy (TEM) image has also confirmed their porous feature. A subsequent plausible formation mechanism of porous LaFeO3 microspheres has been explained in accordance with the Ostwald ripening process. Moreover, gas sensing investigation showed that the sensor based on porous LaFeO3 microspheres exhibited potential applications in monitoring acetone gas due to their unique morphology and porous structure.

  9. Formulation and evalution of montelukast sodium - chitosan based spray dried microspheres for pulmonary drug delivery

    Directory of Open Access Journals (Sweden)

    Rushi Panchal

    2012-01-01

    Full Text Available The objective of present work was to prepare microspheres of montelukast sodium using a natural polymer- chitosan by spray drying method by using glutaraldehyde as a cross linking agent. The microspheres were characterized for size, shape, dissolution, swelling and mucoadhesion. It was observed that, all microspheres were spherical in shape with narrow size distribution. Microspheres had mean particle size of 7-12 μm, with % encapsulation efficiency of 78-86%. The % yield was 32-49% and drug load was 48-53%. With the increase in proportion of chitosan in formulation mucoadhesive strength was increase and also increased in particle size of microspheres. As the drug:polymer ratio increase drug loading was increase and % encapsulation efficiency was also increase.

  10. 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)

  11. CuO/C microspheres as anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.H., E-mail: drhuangxh@hotmail.com [Academy of Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); School of Physics and Electronic Engineering, Taizhou University, Taizhou 318000 (China); Wang, C.B.; Zhang, S.Y. [Academy of Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Zhou, F., E-mail: fzhou@nuaa.edu.cn [Academy of Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2011-07-30

    Highlights: > CuO/C composite microspheres have been successfully prepared by calcining the CuCl{sub 2}/resorcinol-formaldehyde gel in argon atmosphere followed by a subsequent oxidation treatment using H{sub 2}O{sub 2} solution. > CuO particles disperse homogenously inside the carbon aerogel microspheres. > Carbon aerogel microspheres have the abilities of alleviating the pulverization, suppressing the aggregation, and enhancing the conductivity of the CuO particles. Therefore, CuO/C composite microspheres exhibit better electrochemical performance than that of pure CuO. - Abstract: CuO/C microspheres are prepared by calcining CuCl{sub 2}/resorcinol-formaldehyde (RF) gel in argon atmosphere followed by a subsequent oxidation process using H{sub 2}O{sub 2} solution. The microstructure and morphology of materials are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transition electron microscopy (TEM). Carbon microspheres have an average diameter of about 2 {mu}m, and CuO particles with the sizes of 50-200 nm disperse in these microspheres. The electrochemical properties of CuO/C microspheres as anode materials for lithium ion batteries are investigated by galvanostatic discharge-charge and cyclic voltammetry (CV) tests. The results show that CuO/C microspheres deliver discharge and charge capacities of 470 and 440 mAh g{sup -1} after 50 cycles, and they also exhibit better rate capability than that of pure CuO. It is believed that the carbon microspheres play an important role in their electrochemical properties.

  12. Study of deep profile control and oil displacement technologies with nanoscale polymer microspheres.

    Science.gov (United States)

    Hua, Zhao; Lin, Meiqin; Dong, Zhaoxia; Li, Mingyuan; Zhang, Guiqing; Yang, Jie

    2014-06-15

    Scanning electron microscopy (SEM), dynamic lighting scattering (DLS) and HAAKE rheometer experiments were adopted to investigate the shape, size and rheological properties of nanoscale polymer microspheres. Moreover, nuclear-pore film filtration, sand packed tube displacement, core displacement, micro-visual model and capillary flow experiments were used to study the mechanisms of deep profile control and oil displacement of nanoscale polymer microspheres. The results demonstrated that the original shape of the nanoscale polymer microspheres were typically spherical, ranging in size from 30 to 60 nm. When the microspheres were dispersed in water, their size increased by 3-6 times due to swelling and a poly-dispersed system appeared; however, the spherical conformation remained. Within a certain range of shear rates, a 100-900 mg/L microsphere dispersed system exhibited shear thickening behaviour, making it favourable for increasing the flow resistance of a displacement fluid. These polymer microspheres dispersed systems exhibited effective plugging on a nuclear pore film with 0.4-μm pores with deep plugging in the core; these systems also tended to plug the high permeability layer and drive crude oil from the low permeability layer in parallel sand packed tubes. Cross-linked polymer microspheres could reduce water permeability because the microspheres adsorbed, accumulated and bridged in the pore-throat, and the adsorbed layers would be collapsed under the pressure, entering deep into the reservoir due to the good deformation properties of the microspheres. Meanwhile these microspheres would drive crude oil on and in the pores/throats while they are transported in porous media, achieving deep profile control and oil displacement with the ultimate purpose of improving oil recovery. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Design of sustained-release nitrendipine microspheres having solid dispersion structure by quasi-emulsion solvent diffusion method

    DEFF Research Database (Denmark)

    Cui, Fude; Yang, Mingshi; Jiang, Yanyan

    2003-01-01

    that the particle size of microspheres was determined mainly by the agitation speed. The dissolution rate of nitrendipine from microspheres was enhanced significantly with increasing the amount of dispersing agents, and sustained by adding retarding agents. The release rate of microspheres could be controlled...... as amorphous state. The release profiles and content of the microspheres stored at a temperature of 40 degrees C and a relative humidity of 75% were unchanged during 3 months of accelerating condition of storage. And the relative bioavailability of the sustained-release microspheres compared with the Baypress...

  14. Quantifying the influence of humic acid adsorption on colloidal microsphere deposition onto iron-oxide-coated sand

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X. [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG Northern Ireland (United Kingdom); Flynn, R., E-mail: r.flynn@qub.ac.u [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG Northern Ireland (United Kingdom); Kammer, F. von der; Hofmann, T. [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria)

    2010-12-15

    This article describes an approach for quantifying microsphere deposition onto iron-oxide-coated sand under the influence of adsorbed Suwannee River Humic Acid (SRHA). The experimental technique involved a triple pulse injection of model latex microspheres (microspheres) in pulses of (1) microspheres, followed by (2) SRHA, and then (3) microspheres, into a column filled with iron-coated quartz sand as a water-saturated porous medium. A random sequential adsorption model (RSA) simulated the gradual rise in the first (microsphere) breakthrough curve (BTC). Using the same model calibration parameters a dramatic increase in concentration at the start of the second particle BTC, generated after SRHA injection, could be simulated by matching microsphere concentrations to extrapolated RSA output. RSA results and microsphere/SRHA recoveries showed that 1 {mu}g of SRHA could block 5.90 {+-} 0.14 x 10{sup 9} microsphere deposition sites. This figure was consistent between experiments injecting different SRHA masses, despite contrasting microsphere deposition/release regimes generating the second microsphere BTC. - This paper describes a method to quantify the influence of humic acid adsorption on particulate colloid deposition in saturated porous media.

  15. Enhancement of irradiation effects on cancer cells by cross-linked dextran-coated iron oxide (CLIO) nanoparticles

    Science.gov (United States)

    Huang, Fu-Kuo; Chen, Wen-Chang; Lai, Sheng-Feng; Liu, Chi-Jen; Wang, Cheng-Liang; Wang, Chang-Hai; Chen, Hsiang-Hsin; Hua, Tzu-En; Cheng, Yi-Yun; Wu, M. K.; Hwu, Y.; Yang, Chung-Shi; Margaritondo, G.

    2010-01-01

    We investigated iron oxide nanoparticles with two different surface modifications, dextran coating and cross-linked dextran coating, showing that their different internalization affects their capability to enhance radiation damage to cancer cells. The internalization was monitored with an ultrahigh resolution transmission x-ray microscope (TXM), indicating that the differences in the particle surface charge play an essential role and dominate the particle-cell interaction. We found that dextran-coated iron oxide nanoparticles cannot be internalized by HeLa and EMT-6 cells without being functionalized with amino groups (the cross-linked dextran coating) that modify the surface potential from -18 mV to 13.4 mV. The amount of cross-linked dextran-coated iron oxide nanoparticles uptaken by cancer cells reached its maximum, 1.33 × 109 per HeLa cell, when the co-culture concentration was 40 µg Fe mL-1 or more. Standard tests indicated that these internalized nanoparticles increased the damaging effects of x-ray irradiation, whereas they are by themselves biocompatible. These results could lead to interesting therapy applications; furthermore, iron oxide also produces high contrast for magnetic resonance imaging (MRI) in the diagnosis and therapy stages.

  16. In situ preparation of gold nanoparticle-loaded lysozyme-dextran nanogels and applications for cell imaging and drug delivery

    Science.gov (United States)

    Cai, Huanxin; Yao, Ping

    2013-03-01

    An effective, green, and facile approach to synthesize gold nanoparticle-loaded protein-polysaccharide nanogels was developed in this study. Biocompatible gold nanoparticle-loaded lysozyme-dextran (Au@Lys-Dex) nanogels were produced using lysozyme-dextran nanogels as reducing and stabilizing agents. Lysozyme-dextran nanogels have a size of about 200 nm and a structure of lysozyme core and dextran shell. At pH around 4, AuCl4- ions are attracted and locally enriched by lysozyme due to the electrostatic and coordination interactions. When the solution is under UV irradiation, the AuCl4- ions are reduced to gold nanoparticles in situ by solvated electrons and reactive radicals produced from aromatic amino acid residues in the lysozyme. The produced gold nanoparticles with a size of about 8 nm are trapped inside the nanogels and the Au@Lys-Dex nanogels are well dispersible by virtue of the dextran shell. Antitumor drug, doxorubicin, can be loaded effectively inside Au@Lys-Dex nanogels via diffusion. In vitro study demonstrates the doxorubicin loaded Au@Lys-Dex nanogels have the same antitumor activity as free doxorubicin. The nanogels can be used as a contrasting agent in optical cell imaging, in which direct visual images of the subcellular distributions of the gold nanoparticles and the released doxorubicin are presented synchronously. The dual functional drug loaded Au@Lys-Dex nanogels are a promising system for simultaneous drug delivery and biomedical imaging.

  17. Enhancement of irradiation effects on cancer cells by cross-linked dextran-coated iron oxide (CLIO) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Huang, F-K; Chen, W-C; Lai, S-F [Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123, University Rd, Sec. 3, Douliu, Yunlin 64002, Taiwan (China); Liu, C-J; Wang, C-L; Wang, C-H; Chen, H-H; Hua, T-E; Cheng, Y-Y; Wu, M K; Hwu, Y [Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan (China); Yang, C-S [Center for Nanomedicine Research, National Helath Research Institute, Miaoli 350, Taiwan (China); Margaritondo, G [Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)], E-mail: chenwc@yuntech.edu.tw, E-mail: giorgio.margaritondo@epfl.ch

    2010-01-21

    We investigated iron oxide nanoparticles with two different surface modifications, dextran coating and cross-linked dextran coating, showing that their different internalization affects their capability to enhance radiation damage to cancer cells. The internalization was monitored with an ultrahigh resolution transmission x-ray microscope (TXM), indicating that the differences in the particle surface charge play an essential role and dominate the particle-cell interaction. We found that dextran-coated iron oxide nanoparticles cannot be internalized by HeLa and EMT-6 cells without being functionalized with amino groups (the cross-linked dextran coating) that modify the surface potential from -18 mV to 13.4 mV. The amount of cross-linked dextran-coated iron oxide nanoparticles uptaken by cancer cells reached its maximum, 1.33 x 10{sup 9} per HeLa cell, when the co-culture concentration was 40 {mu}g Fe mL{sup -1} or more. Standard tests indicated that these internalized nanoparticles increased the damaging effects of x-ray irradiation, whereas they are by themselves biocompatible. These results could lead to interesting therapy applications; furthermore, iron oxide also produces high contrast for magnetic resonance imaging (MRI) in the diagnosis and therapy stages.

  18. Arginine as an eluent overcomes the hindrance of monoclonal antibody quantification by dextran sulfate in protein A affinity chromatography.

    Science.gov (United States)

    Kim, Bong Gyun; Park, Hong Woo

    2015-01-01

    Analytical chromatography using protein A affinity columns was employed for the fast and simple quantitative analysis of monoclonal antibodies (mAb) from suspension cultures of recombinant Chinese hamster ovary (rCHO) cells. Reliable results could not be obtained from analysis of rCHO cell culture supernatants containing dextran sulfate using elution buffers such as phosphate, glycine, or MgCl2 . These problems increased as the number of analysis and the concentration of dextran sulfate in samples increased. Arginine was identified as an alternative eluent to overcome the hindrance by dextran sulfate. When the samples contain dextran sulfate up to 100 mg/L, the elution buffer containing 0.6-1.0 M arginine at pH 3.0-3.8 is useful for the effective analysis. Reproducible results in the mAb quantification could be obtained by this developed arginine elution buffer from rCHO cell culture supernatants containing dextran sulfate. © 2015 American Institute of Chemical Engineers.

  19. Scale up of dextran production from a mutant of Pediococcus pentosaceus (SPAm using optimized medium in a bioreactor

    Directory of Open Access Journals (Sweden)

    Seema Patel

    2011-12-01

    Full Text Available The mutant of Pediococcus pentosaceus (SPAm produced earlier by UV-mutagenesis exhibiting higher dextransucrase activity as compared to wild-type was used. The generated mutant SPAm gave 12.2 mg/ml, a 20% higher dextran than wild-type. Response surface methodology was carried out for further enhancement of dextran production. To enhance dextran production by the mutant SPAm, Plackett-Burman Design and a 2² full factorial Central Composite Design was employed. After response optimization, the optimum concentration of sucrose and yeast extract was 5.115% (w/v and 0.635% (w/v, respectively. The experimental values of dextran 36.0 mg/ml at flask level and 35.0 mg/ml at bioreactor level were in good agreement with the predicted value of 40.8 mg/ml. The increase in dextran production by the mutant SPAm using the optimized medium was 3 fold higher as compared to unoptimized medium.

  20. Role of carbohydrate receptors in the macrophage uptake of dextran-coated iron oxide nanoparticles.

    Science.gov (United States)

    Chao, Ying; Karmali, Priya Prakash; Simberg, Dmitri

    2012-01-01

    Superparamagnetic iron oxide (SPIO, Ferumoxides, Feridex), an important MRI intravenous contrast reagent, is efficiently recognized and eliminated by macrophages in the liver, spleen, lymph nodes and atherosclerotic lesions. The receptors that recognize nanoparticles are poorly defined and understood. Since SPIO is coated with bacterial polysaccharide dextran, it is important to know whether carbohydrate recognition plays a role in nanoparticle uptake by macrophages. Lectin-like receptors CD206 (macrophage mannose receptor) and SIGNR1 were previously shown to mediate uptake of bacterial polysaccharides. We transiently expressed receptors MGL-1, SIGNR-1 and msDectin-1 in non-macrophage 293T cells using lipofection. The expression was confirmed by reverse transcription PCR. Following incubation with the nanoparticles, the uptake in receptor-expressing cells was not statistically different compared to control cells (GFP-transfected). At the same time, expression of scavenger receptor SR-A1 increased the uptake of nanoparticles three-fold compared to GFP-transfected and control vector-transfected cells. Blocking CD206 with anti-CD206 antibody or with the ligand mannan did not affect SPIO uptake by J774.A1 macrophages. Similarly, there was no inhibition of the uptake by anti-CD11b (Mac-1 integrin) antibody. Polyanionic scavenger receptor ligands heparin, polyinosinic acid, fucoidan and dextran sulfate decreased the uptake of SPIO by J774A.1 macrophages and Kupffer cells by 60-75%. These data unambiguously show that SPIO is taken up via interaction by scavenger receptors, but not via dextran recognition by carbohydrate receptors. Understanding of nanoparticle-receptor interaction can provide guidance for the design of long circulating, non-toxic nanomedicines.

  1. Hyaluronan with dextran added to therapeutic lung surfactants improves effectiveness in vitro and in vivo.

    Science.gov (United States)

    Lu, Karen W; Taeusch, H William; Clements, John A

    2013-01-01

    Surfactants in current clinical use are largely ineffective in treating acute lung injury (ALI)/ acute respiratory distress syndrome. In part, this ineffectiveness is due to inactivation of surfactant by serum leakage into the alveoli. Previously, we reported that adding hyaluronan and some nonionic polymers to synthetic lipids combined with native SP-B and SP-C enhanced surface activity. In this study, we first tested two therapeutic lung surfactants and then retested after adding hyaluronan, polyethylene glycol or dextran alone or in two-polymer combinations including hyaluronan in the absence or presence of serum. Surface activities were measured in a modified bubble surfactometer. Results indicate that the inhibition threshold (defined as the amount of serum required to produce a minimum surface tension above 10 mN/m after 5 minutes of cycling) was 35 times higher with hyaluronan plus dextran added to Infasurf than with Infasurf alone, and better than all other mixtures tested. The threshold for Survanta with hyaluronan plus polyethylene glycol was 7 times higher than Survanta alone. We next tested selected surfactant mixtures in an animal model that mimicked ALI. All measurements of lung function showed significant improvement (P ≤ .05) with hyaluronan, or with hyaluronan and dextran added to Infasurf compared to Infasurf alone. Also, for these two groups, lung function was still improving at the end of the experiment. We conclude that certain polymers added to clinical surfactants can greatly increase resistance to inactivation in vitro, while in vivo, both Infasurf mixtures containing hyaluronan tended to normalize measures of lung function unlike other mixtures tested.

  2. Bacteria penetrate the inner mucus layer before inflammation in the dextran sulfate colitis model.

    Directory of Open Access Journals (Sweden)

    Malin E V Johansson

    2010-08-01

    Full Text Available Protection of the large intestine with its enormous amount of commensal bacteria is a challenge that became easier to understand when we recently could describe that colon has an inner attached mucus layer devoid of bacteria (Johansson et al. (2008 Proc. Natl. Acad. Sci. USA 105, 15064-15069. The bacteria are thus kept at a distance from the epithelial cells and lack of this layer, as in Muc2-null mice, allow bacteria to contact the epithelium. This causes colitis and later on colon cancer, similar to the human disease Ulcerative Colitis, a disease that still lacks a pathogenetic explanation. Dextran Sulfate (DSS in the drinking water is the most widely used animal model for experimental colitis. In this model, the inflammation is observed after 3-5 days, but early events explaining why DSS causes this has not been described.When mucus formed on top of colon explant cultures were exposed to 3% DSS, the thickness of the inner mucus layer decreased and became permeable to 2 microm fluorescent beads after 15 min. Both DSS and Dextran readily penetrated the mucus, but Dextran had no effect on thickness or permeability. When DSS was given in the drinking water to mice and the colon was stained for bacteria and the Muc2 mucin, bacteria were shown to penetrate the inner mucus layer and reach the epithelial cells already within 12 hours, long before any infiltration of inflammatory cells.DSS thus causes quick alterations in the inner colon mucus layer that makes it permeable to bacteria. The bacteria that reach the epithelial cells probably trigger an inflammatory reaction. These observations suggest that altered properties or lack of the inner colon mucus layer may be an initial event in the development of colitis.

  3. LONG-LIVED BONE MARROW PLASMA CELLS DURING IMMUNE RESPONSE TO ALPHA (1→3 DEXTRAN

    Directory of Open Access Journals (Sweden)

    I. N. Chernyshova

    2015-01-01

    Full Text Available Production kinetics and some functional properties of long-lived marrow plasma cells were studied in mice immunized with T-independent type 2 antigens. Alpha (1→3 dextran was used as an antigen for immunization. The mice were immunized by dextran, and the numbers of IgM antibody producing cells were determined by ELISPOT method. The cell phenotype was determined by cytofluorimetric technique. In the area of normal bone marrow lymphocytes ~4% of T and ~85% of B cells were detected. About 35% of the cells expressed a plasmocyte marker (CD138; 3% were CD138+IgM+, and about 6% of the lymphocytes were double-positive for CD138+IgA+. Among spleen lymphocytes, 50% of T and 47% of B cells were detected. About 1.5% lymphocytes were CD138+, and 0.5% were positive for CD138 and IgM. Time kinetics of antibody-producing cells in bone marrow and spleen was different. In spleen populations, the peak amounts of antibody-secreting cells have been shown on the day 4; the process abated by the day 28. Vice versa, the numbers of the antibody-producing cells in bone marrow started to increase on the day 4. The process reached its maximum on day 14, and after 28th day became stationary. The in vitro experiments have shown that supplementation of bone marrow cells from immune mice with dextran did not influence their functional activity. It was previously shown for cells responding to T-dependent antigens only. A specific marker for the long-lived plasma cells is still unknown. However, these cells possess a common CD138 marker specific for all plasma cells. A method for isolation of bone marrow CD138+ cells was developed. The CD138+ cells were of 87-97% purity, being enriched in long-lived bone marrow cells, and produced monospecific antibodies. 

  4. 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.

  5. Influence of dextran coating on the magnetic behaviour of iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dutz, Silvio [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany) and Department of Biomedical Engineering, University of Applied Sciences, Jena (Germany)]. E-mail: silvio.dutz@ipht-jena.de; Andrae, Wilfried [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Department of Biomedical Engineering, University of Applied Sciences, Jena (Germany); Hergt, Rudolf [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Mueller, Robert [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Oestreich, Christiane [Institute of Ceramic Materials, Freiberg University of Mining and Technology (Germany); Schmidt, Christopher [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Department of Materials Engineering, University of Applied Sciences, Jena (Germany); Toepfer, Jorg [Department of Materials Engineering, University of Applied Sciences, Jena (Germany); Zeisberger, Matthias [Institute for Physical High Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Bellemann, Matthias E. [Department of Biomedical Engineering, University of Applied Sciences, Jena (Germany)

    2007-04-15

    Magnetic iron oxide nanoparticles with mean diameters in the range from 10 to 30 nm were prepared by modified chemical precipitation routes. The particles were suspended in an aqueous solution by coating of the particles with carboxymethyldextran. A stability against agglomeration was achieved over a period of more than 7 days. In the present investigation, the structural and the magnetic properties of the nanoparticles were investigated. The influence of the dextran shell on the strength of the dipole-dipole interactions between the neighbouring particles was determined by investigation of the remanence behaviour (Henkel plot) of coated as well as of uncoated particles.

  6. Removal of methyl violet dye by adsorption onto N-benzyltriazole derivatized dextran

    DEFF Research Database (Denmark)

    Cho, Eunae; Tahir, Muhammad Nazir; Kim, Hwanhee

    2015-01-01

    with equilibrium isotherms including the Langmuir, Freundlich, and Temkin models. Based on the Langmuir isotherm, the maximum adsorption capacity was determined to be 95.24 mg of dye per gram of the adsorbent. The adsorption obeyed pseudo-second order kinetics, and a negative Delta G(0) value indicated adsorption...... was characterized by nuclear magnetic resonance spectroscopy, elemental analysis, and scanning electron microscopy. Dextran was substituted with a triazole-linked benzyl group. For decolorization of the dye effluent, adsorption is a very effective treatment; here, the driving force is based on hydrogen bonding, pi...

  7. The Influence of Ghrelin on the Development of Dextran Sodium Sulfate-Induced Colitis in Rats

    OpenAIRE

    Aleksandra Matuszyk; Dagmara Ceranowicz; Zygmunt Warzecha; Piotr Ceranowicz; Krzysztof Fyderek; Krystyna Gałązka; Jakub Cieszkowski; Joanna Bonior; Jolanta Jaworek; Małgorzata Pihut; Artur Dembiński

    2015-01-01

    Ghrelin has protective and therapeutic effects in the gut. The aim of present studies was to investigate the effect of treatment with ghrelin on the development of colitis evoked by dextran sodium sulfate (DSS). Methods. Studies have been performed on rats. Colitis was induced by adding 5% DSS to the drinking water for 5 days. During this period animals were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 8?nmol/kg/dose. On the sixth day, animals were anesthe...

  8. CTAB induced hierarchical bismuth microspheres for visible-light photocatalytic study.

    Science.gov (United States)

    Zhang, Fengnan; Zhao, Yan; Li, Yawen; Wu, Gongjuan; Zhao, Jingzhe

    2017-11-01

    Nanosheet constructed bismuth microspheres were prepared through an aqueous reduction approach in the presence of CTAB molecules, with initial formed BiOCl as the precursor and hydrazine hydrate as the reductant. The flower-like morphology and platelet units of BiOCl precursor determined the evolution of hierarchical Bi microspheres through a morphology-heredity process. Trisodium citrate was introduced to keep the Bi microspheres from oxidation, the high purity in composition are beneficial to eliminate the influence of bismuth oxides. Photocatalytic properties of the hierarchical Bi microspheres were investigated under visible-light irradiation by taking the degradation of rhodamine B (RhB) dye and colorless bisphenol A (BPA) as probe reactions. 99.7% of RhB and 47.4% of BPA degradation in 3h indicate good photocatalytic property of the hierarchical Bi microspheres. Results of storing detection and recycled experiments revealed good structure stability and photocatalytic stability of the Bi microspheres, these properties are vital for practical applications of the materials. The formation mechanism of Bi microspheres and relative degradation mechanism are also proposed on the basis of experimental data. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Fabrication of Magnetic-Antimicrobial-Fluorescent Multifunctional Hybrid Microspheres and Their Properties

    Directory of Open Access Journals (Sweden)

    Ling-Han Xiao

    2013-04-01

    Full Text Available Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate (PGMA template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA and magnetic PGMA (M-PGMA have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride (PHGH functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.

  10. Alginate/quaternized carboxymethyl chitosan/clay nanocomposite microspheres: preparation and drug-controlled release behavior.

    Science.gov (United States)

    Liu, Bo; Luo, Jiwen; Wang, Xiaoying; Lu, Junxiang; Deng, Hongbing; Sun, Runcang

    2013-01-01

    Drug-delivery systems, using natural drug carriers, have become increasingly important because of their nontoxicity and biodegradability. In this study, firstly, quaternized carboxymethyl chitosan (QCMC) was intercalated into the interlayer of organic montmorillonite (OMMT) to obtain the QCMC/OMMT nanocomposites, their structure, morphology, and thermal stability were investigated. Next, crosslinked alginate/QCMC/OMMT (AQCOM) microsphere was obtained by crosslinking with CaCl2, and the drug-controlled release behavior was evaluated with bovine serum albumin (BSA) as model drug. The results suggested that, carboxyl groups in alginate and QCMC crosslinked with Ca(2+), quaternary ammonium groups in QCMC or OMMT electrostatically interacted with carboxyl groups in alginate, and there was stable three-dimensional network in AQCOM microsphere. The swelling ratio of AQCOM microspheres decreased with the increase of OMMT content, the lowest one was only about 45% compared to the microsphere without OMMT of 197%. Besides, the in vitro release results for BSA indicated that the AQCOM microsphere displayed more excellent encapsulation and controlled release capacities than the microsphere without OMMT. The in vitro active cutaneous anaphylaxis test was carried out on Guinea pigs, which revealed that AQCOM microsphere did not cause anaphylaxis. Therefore, QCMC/OMMT nanocomposites from natural materials are considerably suitable to apply as drug-controlled release carriers.

  11. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    Science.gov (United States)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping

    2017-01-01

    In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h+) and superoxide radicals (rad O2-).

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

    Directory of Open Access Journals (Sweden)

    Jae-Won Choi

    2017-09-01

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

  13. Three dimensional distribution of surfactant in microspheres revealed by synchrotron radiation X-ray microcomputed tomography

    Directory of Open Access Journals (Sweden)

    Li Wu

    2017-07-01

    Full Text Available This study investigated the formulation mechanism of microspheres via internal surfactant distribution. Eudragit L100 based microspheres loaded with bovine serum albumin were prepared by solid in oil in oil emulsion solvent evaporation method using acetone and liquid paraffin system containing sucrose stearate as a surfactant. The fabricated microspheres were evaluated for encapsulation efficiency, particle size, production yield, and in vitro release characteristics. The internal structures of microspheres were characterized using synchrotron radiation X-ray microcomputed tomography (SR-µCT. The enhanced contrast made the sucrose stearate distinguished from Eudragit to have its three dimensional (3D distribution. Results indicated that the content and concentration determined the state of sucrose stearate and had significant influences on the release kinetics of protein. The dispersity of sucrose stearate was the primary factor that controlled the structure of the microspheres and further affected the encapsulation efficiency, effective drug loading, as well as in vitro release behavior. In conclusion, the 3D internal distribution of surfactant in microspheres and its effects on protein release behaviors have been revealed for the first time. The highly resolved 3D architecture provides new evidence for the deep understanding of the microsphere formation mechanism.

  14. Biodegradable Chitosan-Based Ambroxol Hydrochloride Microspheres: Effect of Cross-Linking Agents

    Science.gov (United States)

    Gangurde, HH; Chavan, NV; Mundada, AS; Derle, DV; Tamizharasi, S

    2011-01-01

    The objective of this study was to investigate the influence of type of cross-linking method used on the properties of ambroxol hydrochloride microspheres such as encapsulation efficiency, particle size, and drug release. Microspheres were prepared by solvent evaporation technique using chitosan as a matrix-forming agent and cross-linked using formaldehyde and heat treatment. Morphological and physicochemical properties of microspheres were then investigated by scanning electron microscopy (SEM), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and Fourier-transform infrared spectroscopy (FTIR) spectroscopy. The cross-linking of chitosan takes place at the free amino group because of formation of imine bond as evidenced by FTIR. The DSC, XRD, and FTIR analysis showed that chitosan microspheres cross linked by heating were superior in properties and performance as compared to the microspheres cross-linked using formaldehyde. SEM results revealed that heat-treated microspheres were spherical, discrete having smooth, and porous structure. The particle size and encapsulation efficiencies of the prepared chitosan microspheres ranged between 10.83–24.11 μm and 39.73μ80.56%, respectively. The drug release was extended up to 12 h, and the kinetics of the drug release was obeying Higuchi kinetic proving diffusion-controlled drug release. PMID:21607049

  15. 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.

  16. The potential of using biodegradable microspheres in retinal diseases and other intraocular pathologies.

    Science.gov (United States)

    Herrero-Vanrell, Rocío; Bravo-Osuna, Irene; Andrés-Guerrero, Vanessa; Vicario-de-la-Torre, Marta; Molina-Martínez, Irene Teresa

    2014-09-01

    Pathologies affecting the posterior segment of the eye are one of the major causes of blindness in developed countries and are becoming more prevalent due to the increase in society longevity. Successful therapy of diseases affecting the back of the eye requires effective concentrations of the active substance maintained during a long period of time in the intraocular target site. Treatment of vitreoretinal diseases often include repeated intravitreous injections that are associated with adverse effects. Local administration of biodegradable microspheres offers an excellent alternative to multiple administrations, as they are able to deliver the therapeutic molecule in a controlled fashion. Furthermore, injection of microparticles is performed without the need for surgical procedures. As most of the retinal diseases are multifactorial, microspheres result especially promising because they can be loaded with more than one active substance and complemented with the inclusion of additives with pharmacological properties. Personalized therapy can be easily achieved by changing the amount of administered microspheres. Contrary to non-biodegradable devices, biodegradable PLA and PLGA microspheres disappear from the site of administration after delivering the drug. Furthermore, microspheres prepared from these mentioned biomaterials are well tolerated after periocular and intravitreal injections in animals and humans. After injection, PLA and PLGA microspheres suffer aggregation behaving like an implant. Biodegradable microspheres are potential tools in regenerative medicine for retinal repair. According to the reported results, presumably a variety of microparticulate formulations for different ophthalmic therapeutic uses will be available in the clinical practice in the near future. Copyright © 2014. Published by Elsevier Ltd.

  17. The Pharmacokinetics and Pharmacodynamics of Lidocaine-Loaded Biodegradable Poly(lactic-co-glycolic acid) Microspheres

    Science.gov (United States)

    Liu, Jianming; Lv, Xin

    2014-01-01

    The purpose of this study was to develop novel lidocaine microspheres. Microspheres were prepared by the oil-in-water (o/w) emulsion technique using poly(d,l-lactide-co-glycolide acid) (PLGA) for the controlled delivery of lidocaine. The average diameter of lidocaine PLGA microspheres was 2.34 ± 0.3 μm. The poly disperse index was 0.21 ± 0.03, and the zeta potential was +0.34 ± 0.02 mV. The encapsulation efficiency and drug loading of the prepared microspheres were 90.5% ± 4.3% and 11.2% ± 1.4%. In vitro release indicated that the lidocaine microspheres had a well-sustained release efficacy, and in vivo studies showed that the area under the curve of lidocaine in microspheres was 2.02–2.06-fold that of lidocaine injection (p lidocaine microspheres showed a significant release effect in rats, that the process to achieve efficacy was calm and lasting and that the analgesic effect had a significant dose-dependency. PMID:25268618

  18. Performance evaluation of bipolar and tripolar excitations during nozzle-jetting-based alginate microsphere fabrication

    Science.gov (United States)

    Herran, C. Leigh; Huang, Yong; Chai, Wenxuan

    2012-08-01

    Microspheres, small spherical (polymeric) particles with or without second phase materials embedded or encapsulated, are important for many biomedical applications such as drug delivery and organ printing. Scale-up fabrication with the ability to precisely control the microsphere size and morphology has always been of great manufacturing interest. The objective of this work is to experimentally study the performance differences of bipolar and tripolar excitation waveforms in using drop-on-demand (DOD)-based single nozzle jetting for alginate microsphere fabrication. The fabrication performance has been evaluated based on the formability of alginate microspheres as a function of materials properties (sodium alginate and calcium chloride concentrations) and operating conditions. The operating conditions for each excitation include voltage rise/fall times, dwell times and excitation voltage amplitudes. Overall, the bipolar excitation is more robust in making spherical, monodispersed alginate microspheres as good microspheres for its wide working range of material properties and operating conditions, especially during the fabrication of highly viscous materials such as the 2% sodium alginate solution. For both bipolar and tripolar excitations, the sodium alginate concentration and the voltage dwell times should be carefully selected to achieve good microsphere formability.

  19. 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.

  20. Formulation of mucoadhesive microspheres of rosiglitazone maleate and its in vitro evaluation using ionotropic gelation technique

    Directory of Open Access Journals (Sweden)

    Akanksha Garud

    2015-01-01

    Full Text Available Aim: The objective of the present study is to design and evaluate mucoadhesive microspheres for oral controlled release. Materials and Method: Rosiglitazone maleate microspheres with a coat consisting of alginate and a mucoadhesive polymer sodium carboxymethylcellulose, carbopol 934P and hydroxypropylmethylcellulose were prepared by an orifice-ionic gelation process. The microspheres were evaluated for FTIR studies, morphology, particle size, micromeritic properties, percentage entrapment efficiency, in-vitro wash-off test and in-vitro release studies. Results: The resulting microspheres were spherical and free flowing. The percent entrapment efficiency was 68.2 to 85.6%. The microspheres exhibited good mucoadhesive property in the in vitro wash-off test. Rosiglitazone release from these mucoadhesive microspheres was slow and extended over 12 h duration of time depending on the composition of coat. Conclusions: The prepared mucoadhesive microspheres are thus suitable for oral controlled release of Rosiglitazone maleate and thereby help in the management of type II diabetes mellitus.

  1. Modulation of Human Colostrum Phagocyte Activity by the Glycine-Adsorbed Polyethylene Glycol Microspheres

    Directory of Open Access Journals (Sweden)

    Paulo Celso Leventi Guimarães

    2013-01-01

    Full Text Available Colostrum is a secretion that contains immunologically active components, including immunocompetent cells and glycine, which has anti-inflammatory, immunomodulatory, and cytoprotective effects. The aim of this study was to evaluate the adsorption of glycine onto polyethylene glycol (PEG microspheres and to verify the immunomodulatory effect of this nanomaterial on human colostrum phagocytes. The PEG microspheres were evaluated by fluorescence microscopy. The effects of PEG microspheres with adsorbed glycine on viability, superoxide release, phagocytosis, microbicidal activity, and intracellular calcium release of mononuclear (MN and polymorphonuclear (PMN colostrum phagocytes were determined. Fluorescence microscopy analyses revealed that glycine was able to be adsorbed to the PEG microspheres. The PMN phagocytes exposed to glycine-PEG microspheres showed the highest superoxide levels. The phagocytes (both MN and PMN displayed increased microbicidal activity and intracellular calcium release in the presence of PEG microspheres with adsorbed glycine. These data suggest that the adsorption of PEG microspheres with adsorbed glycine was able to stimulate the colostrum phagocytes. This material may represent a possible alternative therapy for future clinical applications on patients with gastrointestinal infections.

  2. Investigation of plasmon properties of silver microsphere array demonstrated experimentally by tip-enhanced Raman spectroscopy

    Science.gov (United States)

    Liu, Yanqi; Zhao, Lijiang; Li, Xinjuan; Zeng, Zhuo; Wang, Peijie; Zhang, Lisheng; Fang, Yan

    2018-01-01

    Due to high spatial resolution and extraordinarily high detection sensitivity of tip-enhanced Raman spectroscopy (TERS), it has attracted more and more attention. However, the tip size and shape, and tip substrate distance have a large impact on the TERS enhancement properties. In this study, a silver microsphere array was prepared on a Polystyrene (PS) microsphere array by vacuum thermal evaporation. And the correlation between the properties of two-dimensional surface-enhanced Raman scattering (SERS) mapping of rhodamine 6G (Rh6G) absorbed on the silver microsphere array and the polarization direction of the incident light was investigated. The effect of the location of the tip on the surface plasmon distribution of the silver microsphere array was also revealed in TERS. In addition, the surface electromagnetic field distribution of the silver microsphere array was simulated by three-dimensional finite-difference time domain (3D-FDTD) method. These results show that the distribution of 'hot spots' on the surface of the silver microsphere array has a dependency on the polarization direction of the incident laser. Moreover, with the introduction of the tip, the 'hot spot' on the surface of the silver microsphere array becomes much more localized and largely enhanced. These results obtained in this paper may have some significance for further studies on the surface plasmon resonance bio-sensing.

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

    Science.gov (United States)

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

    2014-08-01

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

  4. Degradation behavior of theophylline/chitosan/β-cyclodextrin microspheres for pulmonary drug delivery

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-04-01

    Full Text Available To evaluate the degradation behavior of theophylline/chitosan/β-cyclo-dextrin microspheres, we performed both in vitro study by putting the microspheres in phosphate buffered saline or in phosphate buffer saline with enzyme and in vivo study by implanting the microspheres into the back of male Sprague-Dawley rats. The results showed that microspheres were degraded in enzymatic hydrolysis and phosphate buffer saline, which were degraded faster in 0.2 mg/mL lysozyme than in phosphate buffer saline. The morphology of microspheres in phosphate buffer saline and enzyme solution developed rough surfaces, and showed irregular shape and pores after 8 weeks. The microspheres were degraded in vivo within 8 weeks with irregular, sheet, porous morphology, and the diameters were smaller than 5 μm. These results indicated that the theophylline/chitosan/β-cyclodextrin microspheres had a good degradation both in vitro and in vivo which can be used as a pulmonary drug delivery carrier.

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

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    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.

  6. Impact of supramolecular interactions of dextran-β-cyclodextrin polymers on invertase activity in freeze-dried systems.

    Science.gov (United States)

    Santagapita, Patricio R; Mazzobre, M Florencia; Buera, M Pilar; Ramirez, Héctor L; Brizuela, Leissy Gómez; Corti, Horacio R; Villalonga, Reynaldo

    2015-01-01

    β-Cyclodextrin (β-CD)-grafted dextrans with spacer arms of different length were employed to evaluate the impact of supramolecular interactions on invertase activity. The modified dextrans were used as single additives or combined with trehalose in freeze-dried formulations containing invertase. Enzyme activity conservation was analyzed after freeze-drying and thermal treatment. The change of glass transition temperature (Tg ) was also evaluated and related to effective interactions. Outstanding differences on enzyme stability were mainly related to the effect of the spacer arm length on polymer-enzyme interactions, since both the degree of substitution and the molecular weight were similar for the two polymers. This change of effective interactions was also manifested in the pronounced reduction of Tg values, and were related to the chemical modification of the backbone during oxidation, and to the attachment of the β-CD units with spacer arms of different length on dextran. © 2015 American Institute of Chemical Engineers.

  7. [Soluble high molecular weight derivatives of trypsin pancreatic inhibitor. Isolation and properties of dextran-bound pancreatic inhibitor].

    Science.gov (United States)

    Larionova, N I; Kazanskaia, N F; Sakharov, I Iu

    1977-07-01

    A method of isolating preparations of pancreatic inhibitor of trypsin, bound with soluble polysaccharide carriers, is worked out. It is demonstrated that the reaction of a pancreatic inhibitor and cyanuric chloride-activated dextran proceeds for OH groups of tyrosine residues and for-epsilon-NH2 groups of lysine residues. A method is offered of the protection of amino groups with citraconic anhydride for the complete retaining of the inhibitory activity during attachment to dextran. Thermic denaturation of pancreatic inhibitor preparations at pH 4.7 and 97 degrees C is studied. It is found that the modification by 2-amino-4.6-dichloro-s-triazine stabilizes the protein molecule, while the interaction with the matrix of soluble dextran does not carry any contribution to thermostability of the pancreatic inhibitor.

  8. Structure and antioxidant activity of soy protein isolate-dextran conjugates obtained by TiO2 photocatalysis.

    Science.gov (United States)

    Jin, Bei; Zhou, Xiaosong; Li, Bing; Chen, Caiyan; Zhang, Xiaosa; Chen, Siqiao

    2015-01-01

    The aim of this study was to investigate the structural characteristics and antioxidant activities of soy protein isolate- (SPI-) dextran conjugates obtained by TiO2 photocatalysis treatment. Results revealed that the UV-vis absorption and the fluorescence intensity increased as the photocatalytic power increased (P photocatalysis. Moreover, significant changes of secondary structure occurred in SPI-dextran conjugates. The α-helix, β-sheet, β-turns, and random coil were changed from approximately 10.6%, 37.9%, 12.9%, and 38.6% to 3.8%, 10.4%, 17.7%, and 68.8%, respectively, after treatment at photocatalytic power of 1000 W. In addition, SPI-dextran conjugates obtained by TiO2 photocatalysis treatment exhibited high hydroxyl radical scavenging activity and possessed increased reducing power. All data indicated that TiO2 photocatalysis was an efficient method for promoting protein-polysaccharide copolymerisation.

  9. Inhalable bioresponsive chitosan microspheres of doxorubicin and soluble curcumin augmented drug delivery in lung cancer cells.

    Science.gov (United States)

    Jyoti, Kiran; Pandey, Ravi Shankar; Kush, Preeti; Kaushik, Dinesh; Jain, Upendra Kumar; Madan, Jitender

    2017-05-01

    In present investigation, doxorubicin (Dox) and soluble curcumin (Cur-2-HP-β-CD-complex) combination was simultaneously loaded in inhalable bioresponsive chitosan microspheres (Dox/Cur-2-HP-β-CD-complex-elastin-CMs) bearing a substrate-stimuli, elastin. The mean particle size and mean aerodynamic diameter of inhalable bioresponsive microspheres displayed noteworthy differences after incorporation of elastin. Moreover, combination of Dox and soluble curcumin was molecularly dispersed in microspheres matrix as substantiated by a range of spectral techniques. Inhalable bioresponsive microspheres released astonishingly higher amount of Dox in presence of elastase enzyme at pH∼5.5 in comparison to pH∼7.4. However, the release of soluble curcumin from tailored bioresponsive microspheres in presence of elastase enzyme was independent of pH. Consistently, inhalable bioresponsive microspheres exhibited outstandingly lower IC 50 of 3.4-μM in comparison to 6.5-μM of inhalable drug loaded microspheres (Dox/Cur-2-HP-β-CD-complex-CMs) bearing no elastin, against A549, non-small cell lung cancer cells. The superior therapeutic profile of inhalable bioresponsive microspheres may be attributed to enhanced drug release and consequently augmented drug exposure to A549 cells expressing elastase enzyme. In this way, stimuli triggered drug release from tailored inhalable bioresponsive microspheres boosted the phenomena of apoptosis in A549 cells. In conclusion, Dox/Cur-2-HP-β-CD-complex-elastin-CMs warrant further in-vivo tumor regression study to prove its therapeutic efficacy. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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    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.

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

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    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.

  12. 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.

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

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    Wei Xiao

    2016-09-01

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

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

    Science.gov (United States)

    Xiao, Wei; Zhou, Wenjie; Feng, Tong; Zhang, Yanhua; Liu, Hongdong; Tian, Liangliang

    2016-09-20

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

  15. Preparation oral levofloxacin colon-specific microspheres delivery: in vitro and in vivo studies.

    Science.gov (United States)

    Jin, Lei; Ding, Yicun; Feng, Mingli; Cao, Qin

    2016-01-01

    The aim of this study was to prepare levofloxacin-loaded chitosan microspheres and to evaluate their in vitro and in vivo characteristics. Glutaraldehyde-crosslinked microspheres were prepared using a spray-drying method, and characterized in terms of the morphological examination, particle size distribution, entrapment efficiency, drug loading and in vitro release. Pharmacokinetics and colon biodistribution studies were used to evaluate that microspheres have more advantage than the conventional formulations. The surface morphology of the freeze-dried microspheres were smooth, discrete with a regular spherical to near-spherical shape. Size of the microspheres after freeze-drying was 4.96 ± 0.76 μm and well-distributed. The zeta potential of microspheres was -29.3 ± 2.1 mV. An average drug loading of 9.3 ± 0.4% and encapsulation efficiency of 81.1 ± 4.7% of levofloxacin microspheres were obtained with the optimized preparation parameters. The cumulative release rate of levofloxacin microspheres was followed by a sustained release and fitted for classic Higuchi kinetic model. In vivo studies showed that chitosan microspheres are thought to have the potential to maintain levofloxacin concentration within target ranges for a long time, decreasing side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency. It also does not cause any harmful or toxic effect in colon and rectum as evaluated by histopathologic studies.

  16. The effect of medium structure complexity on the growth of Saccharomyces cerevisiae in gelatin-dextran systems.

    Science.gov (United States)

    Boons, Kathleen; Noriega, Estefanía; Verherstraeten, Niels; David, Charlotte C; Hofkens, Johan; Van Impe, Jan F

    2015-04-16

    As most food systems are (semi-)solid, the effect of food structure on bacterial growth has been widely acknowledged. However, studies on the growth dynamics of yeasts have neglected the effect of food structure. In this paper, the growth dynamics of the spoilage yeast Saccharomyces cerevisiae was investigated at 23.5 °C in broth, singular, homogeneous biopolymer systems and binary biopolymer systems with a heterogeneous microstructure. The biopolymers gelatin and dextran were used to introduce the different levels of structure. The metabolizing ability of gelatin and dextran by S. cerevisiae was examined. To study microbial behavior in the binary systems at the micro level, mixtures were imaged with confocal laser scanning microscopy (CLSM). Growth dynamics and microscopic images of S. cerevisiae were compared with those obtained for Escherichia coli in the same model system (Boons et al., 2014). Different phase-separated, heterogeneous microstructures were obtained by changing the amount of added gelatin and dextran. Regardless of the microstructure, S. cerevisiae was preferentially located in the dextran phase. Metabolizing ability-tests indicated that gelatin could be consumed by S. cerevisiae but in the presence of glucose, no change in gelatin concentration was observed. No indication of dextran metabolizing ability was observed. When supplementing broth with gelatin or dextran alone, an enhanced growth rate and maximum cell density were observed. This enhancement was further increased by adding a second biopolymer, introducing a heterogeneous microstructure and hence increasing the medium structure complexity. The results obtained indicate that food structure complexity plays a significant role in the growth dynamics of S. cerevisiae, an important food spoiler. Copyright © 2014. Published by Elsevier B.V.

  17. Evaluation of changes in serum chemistry in association with feed withdrawal or high dose oral gavage with Dextran Sodium Sulfate (DSS) induced gut leakage in broiler chickens

    Science.gov (United States)

    Dextran sodium sulfate (DSS) has been shown to be effective at inducing enteric inflammation in broiler chickens, resulting in increased leakage of orally administered fluorescein isothiocyanate dextran to circulation. In a previous study, two doses of DSS (0.45g/dose) administered as oral gavage re...

  18. Properties of dry masonry mixtures based on hollow aluminosilicate microspheres

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    Semenov Vyacheslav

    2017-01-01

    Full Text Available At present, there is a steady increase in the volume of housing construction in the Russian Federation. The modern trends in the field of energy and resource saving determine the need of the use of efficient building materials that ensure the safety, comfort and minimum cost of housing construction. Among the materials, often used for erecting of fencing structures, it is possible to note effective small-piece elements (ceramic and light-weight concrete units, etc.. To ensure the solidity of such structures, it is necessary to use the masonry mortars whose properties correspond to those of the main wall material. The existing dry mixes for obtaining of such mortars are expensive and often do not meet the minimum physical-and-mechanical and exploitation requirements. The solution of this problem is the usage of the hollow ceramics (aluminosilicate microspheres as a filler for such mixes. The article presents the results of studies of the main physical-and-mechanical and exploitation characteristics of dry masonry mixes with hollow ceramics microspheres modified with various chemical additives. The effect of the compounding factors on the average density and strength of dry masonry mixes was studied. The compositions have been optimized by the methods of mathematical planning.

  19. Photographic assessment of tretinoin microsphere gel in moderate acne.

    Science.gov (United States)

    Feldman, Steven; Nighland, Marge

    2008-08-01

    True objective measures for assessing responsiveness to acne treatments are lacking. Photographic documentation can therefore be a valuable adjunct to treatment assessment. To photographically document the ability of tretinoin microsphere gel (TMG) 0.1% in improving facial acne. A standardized photographic technique was used to assess the efficacy and tolerability of TMG 0.1% applied once nightly for 12 weeks in an open-label trial involving 30 patients (Caucasian and Hispanic) ages 11 to 40 years with moderately severe facial acne. An assessment of frontal, left-sided, and right-sided color photographs at week 12 indicated that TMG 0.1% reduced total, noninflammatory, and inflammatory acne lesion counts by 47.8%, 53.5%, and 33.2%, respectively; and produced an "excellent/ good" investigator's global evaluation (4-point scale) treatment response in 63.6% of patients. Tretinoin microsphere gel 0.1% was well tolerated, and more than 63% of subjects did not exhibit cutaneous adverse effects at week 12. The standardized photographic technique proved to be a useful tool for documenting the efficacy of TMG 0.1% in consistently and significantly improving moderately severe facial acne over a 12-week treatment period.

  20. Biocompatibility of Bletilla striata Microspheres as a Novel Embolic Agent

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    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.

  1. Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification.

    Science.gov (United States)

    Bux, Jaiyana; Manga, Mohamed S; Hunter, Timothy N; Biggs, Simon

    2016-07-28

    Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1-10 l h(-1) scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'. © 2016 The Author(s).

  2. Stabilization of tetanus toxoid encapsulated in PLGA microspheres.

    Science.gov (United States)

    Jiang, Wenlei; Schwendeman, Steven P

    2008-01-01

    Delivery of vaccine antigens from controlled-release poly(lactic/glycolic acid) (PLGA) microspheres is a novel approach to reduce the number of antigen doses required for protection against infection. A major impediment to developing single-shot vaccines is encapsulated antigen instability during months of exposure to physiological conditions. For example, efforts to control neonatal tetanus in developing countries with a single-dose TT vaccine based on PLGA microspheres have been plagued by poor stability of the 150 kDa formaldehyde-detoxified protein antigen, tetanus toxoid (TT), in the polymer. We examined the denatured states of PLGA-encapsulated TT, revealing two primary TT instability mechanisms: (1) protein aggregation mediated by formaldehyde and (2) acid-induced protein unfolding and epitope damage. Further, we systematically identified excipients, which can efficiently inhibit TT aggregation and retain TT antigenicity under simulated deleterious conditions, i.e., elevated temperature and humidity. By employing these novel additives in the PLGA system, we report the slow and continuous release of high doses of TT for one month with retained antigen stability during bioerosion of PLGA.

  3. Yttrium 90 microspheres for the treatment of hepatocellular carcinoma.

    Science.gov (United States)

    Memon, Khairuddin; Lewandowski, Robert J; Riaz, Ahsun; Salem, Riad

    2013-01-01

    Yttrium-90 microspheres are radioactive particles which are increasingly being employed for treating patients with unresectable hepatocellular carcinoma (HCC). The procedure is called radioembolization. It involves the injection of micron-sized embolic particles loaded with a radioisotope by use of transarterial techniques. Because of the sensitivity of liver parenchyma and relative insensitivity of tumor, external radiation has played a limited role in treating HCC. (90)Y administered via arterial route directs the highly concentrated radiation to the tumor while healthy liver parenchyma is relatively spared due to its preferential blood supply from portal venous blood. This technique has proven useful for the majority of patients with HCC as most of them present in advanced stage, beyond potentially curative options (resection/liver transplantation). (90)Y microspheres can be used in downstaging large tumors to bring within transplantable criteria, in patients with portal venous thrombosis due to tumor invasion and as palliative therapy. There are two available devices for (90)Y administration; TheraSphere® (glass based) and SIR-Spheres® (resin based). The procedure is performed on an outpatient basis. The incidence of complications is comparatively less and may include nausea, fatigue, abdominal pain, hepatic dysfunction, biliary injury, fibrosis, radiation pneumonitis, GI ulcers, and vascular injury; however, these can be avoided by meticulous pretreatment assessment, careful patient selection, and adequate dosimetry. This article explores the technical and clinical aspects of (90)Y radioembolization with keeping emphasis on patient selection, uses, and complications.

  4. Chitosan/kaolin composite porous microspheres with high hemostatic efficacy.

    Science.gov (United States)

    Sun, Xun; Tang, Zonghao; Pan, Meng; Wang, Zhengchao; Yang, Hongqin; Liu, Haiqing

    2017-12-01

    The hemostatic performance of chitosan was greatly improved by blending it with kaolin to fabricate porous composite microspheres (CSMS-K) through inverse emulsion method combining with thermally induced phase separation. The CSMS-K had high amount of interior and surface pores. The synergetic hemostatic competence of chitosan and kaolin components made the hemostatic efficacy of CSMS-K superior to chitosan porous microspheres (CSMS). The hemostatic time of CSMS-K3 in the rat tail amputation and liver laceration models was down to respective 120 and 99s from 183 and 134s of CSMS, and the blood loss of CSMS-K3 was respectively 65% and 36% of that of CSMS in the rat tail amputation and liver laceration models. The whole blood clotting kinetics proved that CSMS-K3 formed larger blood clots than CSMS and Celox within a same time period. Our results suggested that the CSMS-K is a potential quick pro-coagulant agent for traumatic hemorrhaging control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Apparatus and process to enhance the uniform formation of hollow glass microspheres

    Science.gov (United States)

    Schumacher, Ray F

    2013-10-01

    A process and apparatus is provided for enhancing the formation of a uniform population of hollow glass microspheres. A burner head is used which directs incoming glass particles away from the cooler perimeter of the flame cone of the gas burner and distributes the glass particles in a uniform manner throughout the more evenly heated portions of the flame zone. As a result, as the glass particles are softened and expand by a released nucleating gas so as to form a hollow glass microsphere, the resulting hollow glass microspheres have a more uniform size and property distribution as a result of experiencing a more homogenous heat treatment process.

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

    Directory of Open Access Journals (Sweden)

    M. J. Barea

    2012-01-01

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

  7. Inhibitory action of dextran on the corrosion of 6061Al–15%(v SiC(P composite in HCl medium

    Directory of Open Access Journals (Sweden)

    B.P. Charitha

    2016-09-01

    Full Text Available Dextran, a biopolymer was used as an eco-friendly inhibitor to control the corrosion of 6061Al–15%(v SiC(P composite in 0.25 M HCl medium. The electrochemical studies like potentiodynamic polarization method, electrochemical impedance spectroscopy techniques were adopted. Evaluation of kinetic and thermodynamic parameters was done. Inhibitor adsorption on the surface of the composite was confirmed by surface morphology studies like SEM and EDX studies. Maximum inhibition efficiency of 80% was obtained at 303 K. Dextran acted as mixed type of inhibitor, underwent physical adsorption and followed Langmuir adsorption isotherm.

  8. Rapid Size- Controlled Synthesis of Dextran-Coated, Copper-Doped Iron Oxide Nanoparticles

    Science.gov (United States)

    Wong, Ray M.

    2011-12-01

    Development of dual modality probes enabled for magnetic resonance imaging (MRI) and positron emission tomography (PET) has been on the rise in recent years due to the potential for these probes to facilitate combining the complementary high resolution of MRI and the high sensitivity of PET. The efficient synthesis of multimodal probes that include the radiolabels for PET can be hindered due to prolonged reaction times during radioisotope incorporation, and the resulting decay of the radiolabel. Along with a time-efficient synthesis, one also needs an optimal synthesis that yields products in a desirable size range (between 20-100 nm) to increase blood retention time. In this work, we describe a novel, rapid, microwave-based synthesis of dextran-coated iron oxide nanoparticles doped with copper (DIO/Cu). Traditional methods for synthesizing dextran-coated iron oxide particles require refluxing for 2 hours and result in approximately 50 nm particles. We demonstrate that microwave synthesis can produce 50 nm nanoparticles in 5 minutes of heating. We discuss the various parameters used in the microwave synthesis protocol to vary the size distribution of DIO/Cu, and demonstrate the successful incorporation of copper into these particles with the aim of future use for rapid 64Cu incorporation.

  9. Carboxymethylated dextran-coated magnetic iron oxide nanoparticles for regenerable bioseparation.

    Science.gov (United States)

    Li, Juan; Zhou, Yu; Li, Meng; Xia, Ning; Huang, Qiyu; Do, Huy; Liu, You-Nian; Zhou, Feimeng

    2011-11-01

    Carboxymethylated dextran (CMD)-coated magnetic iron oxide nanoparticles (MNPs) were synthesized using a co-precipitation method. Compared to neutral dextran coated MNPs, the CMD coating provides good dispersity and colloidal stability to the CMD-MNPs. In particular, the carboxyl groups on the CMD can be readily activated for covalent attachment of antibody molecules. The superparamagnetic property of the antibody-covered CMD-MNPs enables the captured antigen to be separated from the sample solution and CMD coating significantly reduces the nonspecific binding of the nanoparticles. Regeneration of the anti-BSA antibody-covered CMD-MNPs with NaOH does not significantly decrease the antibody activity, and the repeated magnetic separation and washing steps cause only small loss of the starting materials. The method was found to be highly reproducible (RSDs for BSA adsorption and desorption are between 0.78% and 5.1%). The anti-BSA antibody-covered CMD-MNPs possess good selectivity and are able to capture protein antigens from real samples.

  10. Rapid size-controlled synthesis of dextran-coated, 64Cu-doped iron oxide nanoparticles.

    Science.gov (United States)

    Wong, Ray M; Gilbert, Dustin A; Liu, Kai; Louie, Angelique Y

    2012-04-24

    Research into developing dual modality probes enabled for magnetic resonance imaging (MRI) and positron emission tomography (PET) has been on the rise recently due to the potential to combine the high resolution of MRI and the high sensitivity of PET. Current synthesis techniques for developing multimodal probes is largely hindered in part by prolonged reaction times during radioisotope incorporation--leading to a weakening of the radioactivity. Along with a time-efficient synthesis, the resulting products must fit within a critical size range (between 20 and 100 nm) to increase blood retention time. In this work, we describe a novel, rapid, microwave-based synthesis technique to grow dextran-coated iron oxide nanoparticles doped with copper (DIO/Cu). Traditional methods for coprecipitation of dextran-coated iron oxide nanoparticles require refluxing for 2 h and result in approximately 50 nm diameter particles. We demonstrate that microwave synthesis can produce 50 nm nanoparticles with 5 min of heating. We discuss the various parameters used in the microwave synthesis protocol to vary the size distribution of DIO/Cu and demonstrate the successful incorporation of (64)Cu into these particles with the aim of future use for dual-mode MR/PET imaging.

  11. The tolerability of dextran-coated iron oxide nanoparticles during in vivo observation of the rats.

    Science.gov (United States)

    Popa, Cristina L; Prodan, Alina M; Ciobanu, Carmen S; Predoi, Daniela

    2016-07-01

    Superparamagnetic iron oxide nanoparticles (SPION) have attracted a lot of interest due to their widespread biomedical and diagnostic applications. Coating the SPIONs with various surface layers can provide an interface between the core and the surrounding environment. The aim of this study was to examine the in vivo behaviour of dextran-coated iron oxide nanoparticles (D-IONPs) in aqueous suspensions. The SPIONs stabilized with dextran (D-IONPs) were synthesized in aqueous solutions by co-precipitation method. The average grain size deduced from transmission electron microscopy is 7.5 nm. The hematological parameters registered for the rats exposed to D-IONPs at 1 ml/kg have had values approximately equal to those examined for the control specimen. The architecture of liver and kidneys was not affected after one day of intraperitoneal injection of D-IONPs compared to the reference group. After 21 and 28 days respectively from the administration of the D-IONPs solution, the liver and kidneys from the injected rats showed a normal aspect without abnormalities compared to the rats uninjected. Our findings suggest that the administration of 1 ml/kg D-IONPs did not cause any toxicological effect since the parameters of renal and liver function were in the normal range as reported to the control group.

  12. Rapid microwave-assisted synthesis of dextran-coated iron oxide nanoparticles for magnetic resonance imaging

    Science.gov (United States)

    Osborne, Elizabeth A.; Atkins, Tonya M.; Gilbert, Dustin A.; Kauzlarich, Susan M.; Liu, Kai; Louie, Angelique Y.

    2012-06-01

    Currently, magnetic iron oxide nanoparticles are the only nanosized magnetic resonance imaging (MRI) contrast agents approved for clinical use, yet commercial manufacturing of these agents has been limited or discontinued. Though there is still widespread demand for these particles both for clinical use and research, they are difficult to obtain commercially, and complicated syntheses make in-house preparation unfeasible for most biological research labs or clinics. To make commercial production viable and increase accessibility of these products, it is crucial to develop simple, rapid and reproducible preparations of biocompatible iron oxide nanoparticles. Here, we report a rapid, straightforward microwave-assisted synthesis of superparamagnetic dextran-coated iron oxide nanoparticles. The nanoparticles were produced in two hydrodynamic sizes with differing core morphologies by varying the synthetic method as either a two-step or single-step process. A striking benefit of these methods is the ability to obtain swift and consistent results without the necessity for air-, pH- or temperature-sensitive techniques; therefore, reaction times and complex manufacturing processes are greatly reduced as compared to conventional synthetic methods. This is a great benefit for cost-effective translation to commercial production. The nanoparticles are found to be superparamagnetic and exhibit properties consistent for use in MRI. In addition, the dextran coating imparts the water solubility and biocompatibility necessary for in vivo utilization.

  13. Magnetic Composite Thin Films of Fe xO y Nanoparticles and Photocrosslinked Dextran Hydrogels

    Science.gov (United States)

    Brunsen, Annette; Utech, Stefanie; Maskos, Michael; Knoll, Wolfgang; Jonas, Ulrich

    2012-04-01

    Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP-HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By utilizing a surface layer of a photoreactive adhesion promoter on the substrates, the MNP-HG films were covalently immobilized during photocrosslinking. The high stability of the composite was documented by rinsing experiments with UV-Vis spectroscopy, while surface plasmon resonance and optical waveguide mode spectroscopy was employed to investigate the swelling behavior in dependence of the nanoparticle concentration, the particle type, and salt concentration.

  14. Recognition of dextran-superparamagnetic iron oxide nanoparticle conjugates (Feridex) via macrophage scavenger receptor charged domains.

    Science.gov (United States)

    Chao, Ying; Makale, Milan; Karmali, Priya Prakash; Sharikov, Yuriy; Tsigelny, Igor; Merkulov, Sergei; Kesari, Santosh; Wrasidlo, Wolf; Ruoslahti, Erkki; Simberg, Dmitri

    2012-05-16

    Dextran-coated superparamagnetic iron oxide nanoparticles (dextran-SPIO conjugates) offer the attractive possibility of enhancing MRI imaging sensitivity so that small or diffuse lesions can be detected. However, systemically injected SPIOs are rapidly removed by macrophages. We engineered embryonic cells (HEK293T) to express major macrophage scavenger receptor (SR) subtypes including SR-AI, MARCO, and endothelial receptor collectin-12. These SRs possess a positively charged collagen-like (CL) domain and they promoted SPIO uptake, while the charge neutral lipoprotein receptor SR-BI did not. In silico modeling indicated a positive net charge on the CL domain and a net negative charge on the cysteine-rich (CR) domain of MARCO and SR-AI. In vitro experiments revealed that CR domain deletion in SR-AI boosted uptake of SPIO 3-fold, while deletion of MARCO's CR domain abolished this uptake. These data suggest that future studies might productively focus on the validation and further exploration of SR charge fields in SPIO recognition.

  15. Amphiphilic derivatives of dextran: adsorption at air/water and oil/water interfaces.

    Science.gov (United States)

    Rotureau, E; Leonard, M; Dellacherie, E; Durand, A

    2004-11-01

    Ionic amphiphilic dextran derivatives were synthesized by the attachment of sodium sulfopropyl and phenoxy groups on the native polysaccharide. A family of dextran derivatives was thus obtained with varying hydrophobic content and charge density in the polymer chains. The surface-active properties of polymers were studied at the air-water and dodecane-water interfaces using dynamic surface/interfacial tension measurements. The adsorption was shown to begin in a diffusion-limited regime at low polymer concentrations, that is to say, with the diffusion of macromolecules in the bulk solution. In contrast, at long times the interfacial adsorption is limited by interfacial phenomena: adsorption kinetics or transfer into the adsorbed layer. A semiempirical equation developed by Filippov was shown to correctly fit the experimental curves over the whole time range. The presence of ionic groups in the chains strongly lowers the adsorption kinetics. This effect can be interpreted by electrostatic interactions between the free molecules and the already adsorbed ones. The adsorption kinetics at air-water and oil-water interfaces are compared.

  16. Synthesis, Characterization, and Toxicity Evaluation of Dextran-Coated Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mihaela Balas

    2017-02-01

    Full Text Available We report the synthesis of dextran-coated iron oxide magnetic nanoparticles (DIO-NPs with spherical shape and uniform size distribution as well as their accumulation and toxic effects on Jurkat cells up to 72 h. The characterization of dextran-coated maghemite nanoparticles was done by X-ray diffraction and dynamic light scattering analyses, transmission electron microscopy imaging, attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, magnetic hysteresis, and relaxometry measurements. The quantification of DIO-NPs intracellular uptake showed a progressive accumulation of iron as a function of time and dose accompanied by additional lysosome formation and an increasing darkening exhibited by a magnetic resonance imaging (MRI scanner. The cytotoxicity assays revealed a decrease of cell viability and a loss of membrane integrity in a time- and dose-dependent manner. Exposure to DIO-NPs determined an increase in reactive oxygen species level up to 72 h. In the first two days of exposure, the level of reduced glutathione decreased and the amount of malondyaldehyde increased, but at the end of the experiment, their concentrations returned to control values. These nanoparticles could be used as contrast agents for MRI but several parameters concerning their interaction with the cells should be taken into consideration for a safe utilization.

  17. Multifunctional colloidal nanofiber composites including dextran and folic acid as electro-active platforms.

    Science.gov (United States)

    Rzayev, Zakir M O; Bunyatova, Ulviye; Şimșek, Murat

    2017-06-15

    This work presents the fabrication and characterization of novel colloidal multifunctional polymer nanofiber composites (NFCs) from water dispersion blends of intercalated silicate layered nanocomposites of poly (2-vinyl-N-pyrrolidone)/octadecyl amine-montmorillonite (ODA-MMT) and dextran/ODA-MMT as matrix and partner polymer intercalated nanocomposites in the presence of NaOH and folic acid (FA) as doping agents by green reactive electrospinning. Chemical and physical structures, surface morphology and electrical properties were investigated. Effects of matrix/partner polymer ratios, doping agents, absorption time of NaOH, and temperature on electrical parameters of NFCs were evaluated. The presence of FA and increasing dextran fraction in NFCs resulted in reducing fiber diameter and improving diameter distribution. High complexing behaviors of matrix/partner polymer chains, organoclay, FA, and NaOH significantly improved conductivity parameters, especially 5-min of absorption time (≈10 -2 -10 - 3 Sm -1 ). The conductivity of the samples decreased with increasing temperature. NFCs fabricated for the first time are promising candidates for various biomedical, electrochemical and electronic applications as electro-active platforms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Dextran templating for the synthesis of metallic and metal oxide sponges

    Science.gov (United States)

    Walsh, Dominic; Arcelli, Laura; Ikoma, Toshiyuki; Tanaka, Junzo; Mann, Stephen

    2003-06-01

    Silver or gold-containing porous frameworks have been used extensively in catalysis, electrochemistry, heat dissipation and biofiltration. These materials are often prepared by thermal reduction of metal-ion-impregnated porous insoluble supports (such as alumina and pumice), and have surface areas of about 1 m2 g-1, which is typically higher than that obtained for pure metal powders or foils prepared electrolytically or by infiltration and thermal decomposition of insoluble cellulose supports. Starch gels have been used in association with zeolite nanoparticles to produce porous inorganic materials with structural hierarchy, but the use of soft sacrificial templates in the synthesis of metallic sponges has not been investigated. Here we demonstrate that self-supporting macroporous frameworks of silver, gold and copper oxide, as well as composites of silver/copper oxide or silver/titania can be routinely prepared by heating metal-salt-containing pastes of the polysaccharide, dextran, to temperatures between 500 and 900 °C. Magnetic sponges were similarly prepared by replacing the metal salt precursor with preformed iron oxide (magnetite) nanoparticles. The use of dextran as a sacrificial template for the fabrication of metallic and metal oxide sponges should have significant benefits over existing technologies because the method is facile, inexpensive, environmentally benign, and amenable to scale-up and processing.

  19. Synthesis, characterization and antimicrobial activity of dextran sulphate stabilized silver nanoparticles

    Science.gov (United States)

    Cakić, Milorad; Glišić, Slobodan; Nikolić, Goran; Nikolić, Goran M.; Cakić, Katarina; Cvetinov, Miroslav

    2016-04-01

    Dextran sulphate stabilized silver nanoparticles (AgNPs - DS) were synthesized from aqueous solution of silver nitrate (AgNO3) and dextran sulphate sodium salt (DS). The characterization of AgNPs - DS was performed by ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and antimicrobial activity. The formation of AgNPs - DS was monitored by colour changes of the reaction mixture from yellowish to brown and by measuring the surface plasmon resonance absorption peak in UV-VIS spectra at 420 nm. The SEM analysis was used for size and shape determination of AgNPs - DS. The presence of elemental silver and its crystalline structure in AgNPs - DS were confirmed by EDX and XRD analyses. The possible functional groups of DS responsible for the reduction and stabilization of AgNPs were determinated by FTIR spectroscopy. The AgNPs - DS showed strong antibacterial activity against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 11778, Bacillus luteus in haus strain, Bacillus subtilis ATTC 6633, Listeria monocytogenes ATCC 15313, Escherichia coli ATTC 25922, Pseudomonas aeruginosa ATTC 27853, Klebsiella pneumoniae ATTC 700603, Proteus vulgaris ATTC 8427, and antifungal activity against Candida albicans ATTC 2091.

  20. Corneal Thickness During Corneal Collagen Cross-Linking with Isotonic Riboflavin Solution without Dextran

    Directory of Open Access Journals (Sweden)

    Refik Oltulu

    2014-08-01

    Full Text Available Objectives: To monitor the corneal thickness change during the dextran-free isotonic riboflavin solution-aided corneal collagen crosslinking procedure in keratoconus patients. Materials and Methods: Corneal thickness measurements during the corneal collagen cross-linking (CXL treatment for progressive keratoconus were evaluated. The corneal thickness measurements were obtained with ultrasonic pachymetry device at five different time points: 0, 15, and 30 minutes after epithelial removal and 15 and 30 minutes after the initiation of UVA irradiation. Results: Twenty-four eyes of 24 patients with progressive keratoconus were included in the study. The thinnest pachymetric values obtained at the 0, 15, and 30 minute measurements after corneal deepithelisation were 409.38±10.43 µm (383-435 µm, 434.56±17.68 µm (400-485 µm, and 457.44±21.78 µm (428-516 µm, respectively. Pachymetric values obtained at 15 and 30 minutes after UVA application to the cornea were 471.69±23.38 µm (439-526 µm and 482.63±23.69 µm (436-524 µm, respectively. The gradual increase was found to be statistically significant when each measurement was compared with the previous values (p<0.001. Conclusion: We found that the corneal thickness was not decreased during the CXL with dextran-free isotonic riboflavin solution; on the contrary, corneal thickness was increased regularly during the procedure. (Turk J Ophthalmol 2014; 44: 272-4

  1. Poultry enteric inflammation model with dextran sodium sulfate mediated chemical induction and feed restriction in broilers.

    Science.gov (United States)

    Kuttappan, V A; Berghman, L R; Vicuña, E A; Latorre, J D; Menconi, A; Wolchok, J D; Wolfenden, A D; Faulkner, O B; Tellez, G I; Hargis, B M; Bielke, L R

    2015-06-01

    Gut inflammation is a cardinal event occurring in various gastrointestinal diseases regardless of etiology. A potential mechanism of action for antibiotic growth promoters and probiotics is alleviation or attenuation of such inflammation. In vivo inflammation models and markers to quantify changes in inflammation, such as paracellular leakage and tight junction function, are necessary tools in the search for methods to reduce enteric inflammation. Dextran sodium sulfate (DSS) and feed restriction (FRS), and fluorescein isothiocyanate dextran (FITC-d; 3 to 5 kDa) marker were evaluated for induction and assessment of enteric inflammation in broilers. Three independent experiments were conducted where birds received an inflammation inducer treatment and an oral gavage of FITC-d (2.2 mg/bird) 2.5 h before killing on d 4, followed by measurement of serum FITC-d levels and release of FITC-d from different regions of gastrointestinal tract (GIT) to evaluate tight junction function. Experiment 1 tested control (CON) and DSS; Experiments 2 and 3 evaluated CON, DSS, and FRS. In all experiments DSS, as well as FRS in Experiments 2 and 3, showed higher (PPoultry Science Association Inc.

  2. Dilational rheology of oil/water interfaces covered by amphiphilic polysaccharides derived from dextran.

    Science.gov (United States)

    Desbrières, Jacques; López-Gonzalez, Edeluc; Aguilera-Miguel, Antonio; Sadtler, Véronique; Marchal, Philippe; Castel, Christophe; Choplin, Lionel; Durand, Alain

    2017-12-01

    This work studied the adsorption at dodecane/water interface of amphiphilic polysaccharides derived from dextran (a nonionic bacterial polysaccharide) by random attachment of phenoxy groups along the chains (between 10 and 20 attached phenoxy groups per 100 glucose repeat units). The long-time kinetics of interfacial tension decrease was satisfactorily described assuming diffusion-limited adsorption of hydrophobic units (over 4h). Dilational rheology of dodecane/water interface was studied for the first time with that kind of amphiphilic polysaccharides and evidenced a significant elastic component. For all dextran derivatives, experimental results were conveniently described using Lucassen-van den Tempel model which assumed diffusion-limited of surface active species. The characteristic frequency increased with the number of attached phenoxy groups and its order of magnitude (10 -3 -10 -2 rad.s -1 ) was consistent with estimations based on the previous model. Experimental results were compared to those obtained with commercial stabilizers like Pluronics (L64, P105, F68 and F127) and Tween 80. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Fabrication of aptamer decorated dextran coated nano-graphene oxide for targeted drug delivery.

    Science.gov (United States)

    Alibolandi, Mona; Mohammadi, Marzieh; Taghdisi, Seyed Mohammad; Ramezani, Mohammad; Abnous, Khalil

    2017-01-02

    In the current study, dextran (DEX) was covalently conjugated to the surface of nano-GO sheets, making stable biocompatible dextran coated GO (GO-DEX). The prepared GO-DEX was nontoxic to 4T1 mammary carcinoma cell line at concentrations up to 300μg/mL. AS1411 aptamer, a ssDNA aptamer which can improve the intracellular uptake by nucleolin recognition, also has been introduced to hydroxyl groups of DEX in GO-DEX to produce GO-DEX-Apt. Moreover, curcumin (CUR), a natural polyphenol, found in the rhizomes of Curcuma longa (turmeric) which shows antineoplastic effects, was loaded onto the GO-DEX and GO-DEX-Apt via π-π stacking interactions with a high loading capacity (∼29wt%). The GO-DEX-Apt-CUR could efficiently enter into 4T1 and MCF-7 nucleolin over-expressed cancer cells confirmed by fluorescence microscope and flowcytometry, and it also showed significantly higher cytotoxicity. These types of targeted nanoscale drug delivery vehicles on the basis of DEX coated GO may find potential application in cancer chemotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Microspheres for the oral delivery of insulin: preparation, evaluation and hypoglycaemic effect in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Zhang, Huan; Wang, Weimei; Li, Haoran; Peng, Yi; Zhang, Zhiqing

    2018-01-01

    Insulin-loaded microspheres were prepared by alternating deposition film layers that were composed of insulin and poly(vinyl sulfate) potassium on the surface of poly(lactic acid) (PLA) microspheres. The preparation of the insulin-loaded microspheres was optimized by an orthogonal test design, and the relationship between drug loading (DL) and film layers was studied. The particle size, DL and encapsulation efficiency of the obtained insulin-loaded microspheres with 10 films were 5.25 ± 0.15 µm, 111.33 ± 1.15 mg/g and 33.7 ± 0.19%, respectively. Following this, the physical characteristics of the insulin-loaded microspheres were investigated. The results from scanning electron microscopy and a laser particle size analyzer (LPSA) indicated the spherical morphology, rough surface and increasing particle sizes of the insulin-loaded microspheres, which were compared to those of PLA microspheres. An in vitro release study showed that the insulin-loaded microspheres were stable in HCl solution (pH 1.0) and released insulin slowly in phosphate-buffered solution (pH 6.8). Finally, the drug efficacy of the prepared insulin-loaded microspheres via oral administration was evaluated in rats with diabetes induced by streptozotocin, and an obvious dose-dependent hypoglycemic effect was observed. This preliminary data could illustrate the prospect of using microspheres for the oral delivery of insulin.

  5. Effect of interfacial serum proteins on melanoma cell adhesion to biodegradable poly(l-lactic acid) microspheres coated with hydroxyapatite.

    Science.gov (United States)

    Shinto, Hiroyuki; Hirata, Takuya; Fukasawa, Tomonori; Fujii, Syuji; Maeda, Hayata; Okada, Masahiro; Nakamura, Yoshinobu; Furuzono, Tsutomu

    2013-08-01

    We have measured the interaction forces between a murine melanoma cell and a poly(l-lactic acid) (PLLA) microsphere coated with/without hydroxyapatite (HAp) nanoparticles (i.e., an HAp/PLLA or a bare PLLA microsphere) in a serum-free culture medium, using atomic force microscopy (AFM) with colloid probe technique, in order to investigate how the HAp-nanoparticle coating as well as interfacial serum proteins influence the cell-microsphere adhesion. The cell adhesion force of the HAp/PLLA microspheres was 1.4-fold stronger than that of the bare PLLA microspheres. When the microspheres were pretreated with a culture medium supplemented with 10% fetal bovine serum, the cell adhesion force of the HAp/PLLA microspheres was increased by a factor of 2.1; in contrast, no change was observed in the cell adhesion force of the bare PLLA microspheres before/after the pretreatment. Indeed, the cell adhesion force of the HAp/PLLA was 2.8-fold larger than that of the bare PLLA after the pretreatment. Additionally, we have investigated the effect of interfacial serum proteins on the zeta potentials of these microspheres. On the basis of the obtained results, possible mechanism of cell adhesion to the HAp/PLLA and bare PLLA microspheres in the presence/absence of the interfacial serum proteins is discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. In Vitro and In Vivo Suppression of Cellular Activity by Guanidinoethyl Disulfide Released from Hydrogel Microspheres Composed of Partially Oxidized Hyaluronan and Gelatin

    Science.gov (United States)

    Weng, Lihui; Ivanova, Natalia D.; Zakhaleva, Julia; Chen, Weiliam

    2008-01-01

    This paper describes the preparation of oxidized hyaluronan crosslinked gelatin microspheres for drug delivery. Microspheres were prepared by a modified water-in-oil-emulsion crosslinking method, where 3-dimensional crosslinked hydrogel microspheres formed in the absence of any extraneous crosslinker. SEM analyses of the microspheres showed rough surfaces in their dried state with an average diameter of 90 µm. Lyophilization of fully-swollen microspheres revealed a highly porous structure. Guanidinoethyl disulfide (GED) was used as a model drug for incorporation into the microspheres; encapsulation of GED was confirmed by HPLC. There was an inverse correlation between the diameters of the microspheres with their GED loading. Macrophage was used as a model cell to evaluate the in vitro efficacy of GED release from the microspheres. The in vivo efficacy of the microspheres was further validated in a mouse full-thickness transcutaneous dermal wound model through suppression of cell infiltration. PMID:18678403

  7. 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.

  8. Multifunctional microsphere formulation of fluorescent magnetic properties for drug delivery system

    Science.gov (United States)

    Kusrini, Eny; Prassanti, Riesna; Nurjaya, Dwi Marta; Gunawan, Cindy

    2017-02-01

    The microsphere formulations of Chit/TPP/Sm/Fe3O4/Rn were prepared by an ionic gelation technique, where Chit=chitosan, TPP=tripolyphosphate, Sm=samarium and Rn=ranitidine. Optimum of microsphere formulation exhibit magnetic and fluorescent properties with adsorption efficiency of ˜92% was obtained for Chit/TPP/Sm/Fe3O4/Rn with ratio 400:500:50:1:20. Fluorescence intensity of microsphere formulations increased with the cumulative amount release of ranitidine, so that the changing of fluorescence intensity at wavelength of 590 nm referring to the Sm3+ ion could be used as indicator in DDS. With the demonstration of sustained release from microsphere formulation, it allows to investigate the applications to other drugs.

  9. Development of alginate microspheres containing thyme essential oil using ionic gelation.

    Science.gov (United States)

    Benavides, Sergio; Cortés, Pablo; Parada, Javier; Franco, Wendy

    2016-08-01

    Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000rpm/5min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Controllable synthesis of self-assembly Co3O4 nanoflake microspheres for electrochemical performance

    Science.gov (United States)

    Liu, Fangyan; Zhang, Binbin; Su, Hai; Zhang, Haitao; Zhang, Lei; Yang, Weiqing

    2016-09-01

    Tuning the ratios of ethanol to water, self-assembling microspheres composed of Co3O4 nanoflakes are synthesized by the hydrothermal method. The scanning electron microscopy (SEM) images of as-grown samples obviously show that the dispersive multilayered structures gradually change into micro/nanobelts and cubic blocks structures, and then into the desired self-assembled microspheres with increasing ratios of ethanol to water. Also, all the x-ray diffraction (XRD) patterns evidently demonstrate that all obtained Co3O4 has cubic crystal structure. The corresponding synthesis mechanism is discussed in detail. More importantly, the unique self-assembling Co3O4 nanoflake microspheres have excellent electrochemical performance with large specific capacitance, good rate capability and excellent cycling performance, evidently presenting a potential capability of Co3O4 nanoflake microspheres to act as electrode materials for supercapacitors in sustainable power sources.

  11. Trapping of a microsphere pendulum through cavity-enhanced optical forces

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yuqiang; Chormaic, Sile Nic [Physics Department, University College Cork, Cork (Ireland); M Ward, Jonathan [Photonics Centre, Tyndall National Institute, Prospect Row, Cork (Ireland); Minogin, Vladimir G, E-mail: yuqiang.wu@tyndall.i [Institute of Spectroscopy, Russian Academy of Sciences, 142190 Troitsk, Moscow Region (Russian Federation)

    2010-09-01

    Optical forces resulting from evanescently coupled microcavities can produce remarkable mechanical effects on micro- and nanoscale systems. Excitation of the symmetric and antisymmetric modes of the interacting whispering gallery modes (WGM) leads to significant attractive and repulsive forces. Here, we propose a method to spatially trap a microspherical resonator pendulum via the optical forces produced by two simultaneously excited WGMs of a photonic molecule, comprising two microspherical cavities. We discuss how the cavity-enhanced optical force generated in the photonic molecule can create an optomechanical potential of about 5 eV deep and 10 pm wide, which can be used to trap the pendulum at any given equilibrium position by a simple choice of laser frequencies. This result presents opportunities for very precise all-optical self-alignment of microsystems. Frequency splitting of a co-resonant mode from two similar-sized microspheres was observed experimentally and the mechanical characteristics of a microsphere pendulum were also studied.

  12. Low-threshold stimulated Brillouin scattering in high-Q whispering gallery mode tellurite microspheres.

    Science.gov (United States)

    Guo, Changlei; Che, Kaijun; Zhang, Pan; Wu, Jinshu; Huang, Yantang; Xu, Huiying; Cai, Zhiping

    2015-12-14

    We demonstrate the first observation of stimulated Brillouin scattering (SBS) in a high-Q whispering gallery mode tellurite microsphere. Tellurite glass with composition of 70TeO₂-20ZnO-5Na₂O-5La₂O₃ (molar ratio) was prepared in-house using a melt-quenching technique. Moreover, tellurite microspheres with Q in excess of 13 millions at 1550 nm were fabricated by melting tellurite microwires using a CO₂ laser. By pumping the tellurite microspheres with a tunable single frequency laser, SBS is further realized with a threshold as low as 0.58 mW. At last, the beat notes between the pump and the Stokes signals were measured, which indicated the Brillouin frequency shift is at the 8.2 GHz band for our tellurite glass. Our results could propel significant applications utilizing SBS by employing tellurite microspheres.

  13. In Planta Microsphere-Based Lateral Flow Leaf Biosensor in Maize

    National Research Council Canada - National Science Library

    Wen, Jessica T; Castro, Carlos; Tsutsui, Hideaki

    2015-01-01

    .... Here, we report a new lateral flow detection technology directly integrated in a maize leaf, in which microspheres conjugated with analyte-specific capture antibodies are non-invasively injected...

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-15

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

  16. Chitosan microspheres applied for removal of oil from produced water in the oil industry

    Directory of Open Access Journals (Sweden)

    Izabel Cristina da Silva Grem

    2013-01-01

    Full Text Available The discharge of oily wastewaters in the environment is steadily increasing, causing serious damages. Among various treatment methods, adsorption is generally considered the most appropriate, since it can remove both organic and inorganic pollutants. Adsorption using low-cost alternative biopolymers for removal of contaminants from wastewater has been widely investigated. In this context, chitosan has been drawing particular attention because, among its many applications, it can be used in the treatment of aqueous effluents. In this study, microspheres were prepared by reticulation of chitosan with sodium triphosphate (STP and studied for the treatment of water containing crude oil. The microspheres were regular and had surface pores. These microspheres were packed in treatment columns and their ability to remove oil was measured with a fluorometer, by the difference in the oil concentration before and after passing through the column. The microspheres that presented porosity about 80 % were highly efficient in oil removal, with rates above 90%.

  17. Biodegradable Vaccine Microspheres for System and Mucosal Immunization Against Equine Encephalitis

    National Research Council Canada - National Science Library

    Michalek, Suzanne

    2000-01-01

    The goals of the proposed studies are to show that pulse-release microsphere vaccines consisting of antigen and adjuvant is an effective and efficacious method for inducing protective immune responses...

  18. Biodegradable Vaccine Microspheres for Systemic and Mucosal Immunization Against Equine Encephalitis

    National Research Council Canada - National Science Library

    Michalek, Suzanne

    1999-01-01

    The goals of the proposed studies are to show that pulse-release microsphere vaccines consisting of antigen and adjuvant is an effective and efficacious method for inducing protective immune responses...

  19. Properties and self-healing behavior of oil absorbent microspheres modified cement

    Science.gov (United States)

    Wang, Chunyu; Bu, Yuhuan; Zhao, Letian

    2017-09-01

    This paper concerns the properties and self-healing behavior of cement composites modified by oil absorbent microspheres with fumed silica shell. These microspheres, prepared by Pickering polymerization, possessed excellent properties, such as uniform particle size, good hydrophilicity and fine thermal stability. Furthermore, the effect of these microspheres on the properties of cement slurry was studied. The results showed that these microspheres had good compatibility with cement slurry, except for a slight effect on the consistency of cement slurry and the compressive strength of cement stone. At last, we derived the mathematical formulation of valid sealing for microcracks in self-healing cement, and measured sealing pressure under different filling conditions. The self-healing cement would guarantee the health, safety and high efficiency in the process of oil and gas production.

  20. Composition, morphology, properties of coal fly ash microspheres and their application for conditioning liquid radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Anshits, N.N. [Institute of Chemistry and Chemical Technology, SB RAS (ICCT SB RAS), Krasnoyarsk (Russian Federation)]. E-mail: anshits@icct.ru; Salanov, A.N.; Vereshchagina, T.A.; Kruchek, D.M.; Bajukov, O.A.; Tretyakov, A.A.; Revenko, Yu.A.; Anshits, A.G

    2006-07-01

    Using methods of the Moessbauer spectroscopy, scanning electron microscopy, and thermodynamic analysis of phase formation in silicate multi-component melts, the detailed study of composition, morphology, and properties of fly ash microspheres resulting from combustion of three coals (Irsha-Borodinskii, Kuznetskii and Ekibastuzskii) was carried out. About 60 microspherical products with an iron content of 2-94 wt.% Fe{sub 2}O{sub 3} were obtained. The ranges of microsphere composition, suitable for liquid radioactive waste solidification in the forms of iron phosphate (36-94 wt.% Fe{sub 2}O{sub 3}) and aluminosilicate (2-20 wt.% Fe{sub 2}O{sub 3}) ceramics were determined. The possibility of producing porous materials and specific microspherical sorbents, based on coal fly ash cenospheres and their application for mobilisation of liquid radioactive waste solidification was demonstrated. (author)

  1. Microwave absorbing properties of hollow microspheres plated with magnetic metal films

    Science.gov (United States)

    Kim, Sun-Tae; Kim, Sung-Soo

    2014-05-01

    Conductive and magnetic microspheres are fabricated through the electroless plating of Co, Co-10%Fe, Ni, and Ni-15%Fe films on hollow microspheres (cenospheres), and their high frequency electromagnetic and microwave absorbing properties are investigated in the composite specimens. The electroless plating of the metal films is conducted using a two-step process of surface sensitizing and metal plating. For the microspheres coated with the Co and Co-10%Fe films, impedance matching is not satisfied at all frequencies due to the small values of magnetic loss and dielectric constant. For the Ni-plated microsphere composites, the dielectric constant is too high to satisfy the impedance matching, which results in a small value of microwave absorbance. For the Ni-15%Fe thin film composite with appropriate magnetic permeability and dielectric permittivity, the impedance matching is satisfied in the GHz frequency and a lower value of reflection loss is predicted.

  2. One-step synthesis of chitosan-silica hybrid microspheres in a microfluidic device.

    Science.gov (United States)

    Lan, Wenjie; Li, Shaowei; Xu, Jianhong; Luo, Guangsheng

    2010-12-01

    This article describes a simple microfluidic method to fabricate chitosan-silica hybrid microspheres in one step. We dissolved tetraethoxysilane (TEOS) into a chitosan/acetic acid aqueous solution to form a chitosan-silica sol, and then emulsified it in an organic phase mainly containing n-octanol and an organic base triotylamine (TOA) via a co-axial microfluidic device. The formed aqueous droplets were solidified because of the extraction of acetic acid and water to the organic phase. The simple method presented has the advantages of controllable sphere diameter, narrow size distribution and good sphericity. The porous structures of the microspheres were displayed by SEM images. It is found that the inner and surface structures can be controlled by adjusting the solidification reagent component. Furthermore, we chemically grafted bovine serum albumin (BSA) on the microspheres. The existence of silica in the chitosan spheres can enhance both of mechanical intensity and protein loading capacity of the microspheres.

  3. Angiogenic microspheres promote neural regeneration and motor function recovery after spinal cord injury in rats

    Science.gov (United States)

    Yu, Shukui; Yao, Shenglian; Wen, Yujun; Wang, Ying; Wang, Hao; Xu, Qunyuan

    2016-01-01

    This study examined sustained co-delivery of vascular endothelial growth factor (VEGF), angiopoietin-1 and basic fibroblast growth factor (bFGF) encapsulated in angiogenic microspheres. These spheres were delivered to sites of spinal cord contusion injury in rats, and their ability to induce vessel formation, neural regeneration and improve hindlimb motor function was assessed. At 2–8 weeks after spinal cord injury, ELISA-determined levels of VEGF, angiopoietin-1, and bFGF were significantly higher in spinal cord tissues in rats that received angiogenic microspheres than in those that received empty microspheres. Sites of injury in animals that received angiogenic microspheres also contained greater numbers of isolectin B4-binding vessels and cells positive for nestin or β III-tubulin (P spinal cord injury and markedly stimulate angiogenesis and neurogenesis, accelerating recovery of neurologic function. PMID:27641997

  4. Olive oil DNA fingerprinting by multiplex SNP genotyping on fluorescent microspheres.

    Science.gov (United States)

    Kalogianni, Despina P; Bazakos, Christos; Boutsika, Lemonia M; Targem, Mehdi Ben; Christopoulos, Theodore K; Kalaitzis, Panagiotis; Ioannou, Penelope C

    2015-04-01

    Olive oil cultivar verification is of primary importance for the competitiveness of the product and the protection of consumers and producers from fraudulence. Single-nucleotide polymorphisms (SNPs) have emerged as excellent DNA markers for authenticity testing. This paper reports the first multiplex SNP genotyping assay for olive oil cultivar identification that is performed on a suspension of fluorescence-encoded microspheres. Up to 100 sets of microspheres, with unique "fluorescence signatures", are available. Allele discrimination was accomplished by primer extension reaction. The reaction products were captured via hybridization on the microspheres and analyzed, within seconds, by a flow cytometer. The "fluorescence signature" of each microsphere is assigned to a specific allele, whereas the signal from a reporter fluorophore denotes the presence of the allele. As a model, a panel of three SNPs was chosen that enabled identification of five common Greek olive cultivars (Adramytini, Chondrolia Chalkidikis, Kalamon, Koroneiki, and Valanolia).

  5. Highly Sensitive and Reproducible SERS Performance from Uniform Film Assembled by Magnetic Noble Metal Composite Microspheres.

    Science.gov (United States)

    Niu, Chunyu; Zou, Bingfang; Wang, Yongqiang; Cheng, Lin; Zheng, Haihong; Zhou, Shaomin

    2016-01-26

    To realize highly sensitive and reproducible SERS performance, a new route was put forward to construct uniform SERS film by using magnetic composite microspheres. In the experiment, monodisperse Fe3O4@SiO2@Ag microspheres with hierarchical surface were developed and used as building block of SERS substrate, which not only realized fast capturing analyte through dispersion and collection under external magnet but also could be built into uniform film through magnetically induced self-assembly. By using R6G as probe molecule, the as-obtained uniform film exhibited great improvement on SERS performance in both sensitivity and reproducibility when compared with nonuniform film, demonstrating the perfect integration of high sensitivity of hierarchal noble metal microspheres and high reproducibility of ordered microspheres array. Furthermore, the as-obtained product was used to detect pesticide thiram and also exhibited excellent SERS performance for trace detection.

  6. Design and Fabrication of Microspheres with Hierarchical Internal Structure for Tuning Battery Performance.

    Science.gov (United States)

    Nowack, Lea V; Bunjaku, Teutë; Wegner, Karsten; Pratsinis, Sotiris E; Luisier, Mathieu; Wood, Vanessa

    2015-06-01

    Microspheres with controlled nano- and macroporosity are fabricated by template-assisted spray drying. Increasing the porosity of the particle up to 20% improves the rate performance of the particles as shown experimentally and by electrochemical simulations of particle lithiation.

  7. Design and Fabrication of Microspheres with Hierarchical Internal Structure for Tuning Battery Performance

    OpenAIRE

    Nowack, Lea V.; Bunjaku, Teut?; Wegner, Karsten; Pratsinis, Sotiris E.; Luisier, Mathieu; Wood, Vanessa

    2015-01-01

    Microspheres with controlled nano? and macroporosity are fabricated by template?assisted spray drying. Increasing the porosity of the particle up to 20% improves the rate performance of the particles as shown experimentally and by electrochemical simulations of particle lithiation.

  8. Design and Fabrication of Microspheres with Hierarchical Internal Structure for Tuning Battery Performance

    OpenAIRE

    Novak Lea; Bunjaku Teute; Wenger Karsten; Pratsinis Sotiris; Luisier Mathieu; Wood Vanessa

    2015-01-01

    Microspheres with controlled nano and macroporosity are fabricated by template assisted spray drying. Increasing the porosity of the particle up to 20 improves the rate performance of the particles as shown experimentally and by electrochemical simulations of particle lithiation.

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

    Directory of Open Access Journals (Sweden)

    Michael Bugiel

    2015-11-01

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

  10. BiOBr microspheres for photocatalytic degradation of an anionic dye

    Science.gov (United States)

    Mera, Adriana C.; Váldes, Héctor; Jamett, Fabiola J.; Meléndrez, M. F.

    2017-03-01

    BiOBr microspheres were obtained using a solvothermal synthesis route in the presence of ethylene glycol and KBr at 145 °C, for 18 h. BiOBr microspheres were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), nitrogen adsorption-desorption isotherms analysis, diffuse reflectance spectroscopy (DRS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Additionally, the theoretical and experimental isoelectric points (IEP) of BiOBr nanostructured microspheres were determined, and pH's influence on the degradation of an anionic dye (methyl orange) under simulated solar radiation was analyzed. Results show that 97% of methyl orange is removed at pH 2 after 60 min of photocatalytic reaction. Finally, DRIFTS studies permit the proposal of a surface reaction mechanism of the photocatalytic oxidation of MO using BiOBr microspheres.

  11. Enhanced pharmacokinetics of omeprazole when formulated as gastroretentive microspheres along with piperine

    Directory of Open Access Journals (Sweden)

    Bindu Madhavi Boddupalli

    2014-02-01

    Full Text Available Objective: To investigate the formulation of gastroretentive microspheres of omeprazole along with piperine and estimate the pharmacokinetic parameters in comparison with omeprazole alone. Methods: In our present investigation, gastroretentive microspheres of omeprazole were prepared with the inclusion of piperine. Pharmacokinetic parameters like Cmax, Tmax and area under curve were estimated by administering the prepared microspheres to rabbits and the results were compared with omeprazole alone. Results: There was a significant increase in area under curve from 3.441依1.093 mg·h/mL to 14.422 依0.708 mg·h/mL along with an increase in Cmax. Conclusions: This clearly shows the increased absorption and decreased metabolism of omeprazole when administered along with piperine as gastroretentive microspheres.

  12. Development and characterization of mucoadhesive microspheres for nasal delivery of ketorolac.

    Science.gov (United States)

    Nagda, C D; Chotai, N P; Nagda, D C; Patel, S B; Patel, U L

    2011-04-01

    The objective of the present investigation was to prepare mucoadhesive microspheres of ketorolac for nasal administration by means of a solvent evaporation technique using carbopol (CP), polycarbophil (PL) and chitosan (CS) as mucoadhesive polymers. The prepared microspheres were characterized for morphology, swelling behavior, mucoadhesion, interaction studies, drug encapsulation efficiency, in vitro drug release, release kinetics, and ex vivo nasal cilio toxicity studies. The effects of various process variables on the particle size of the microspheres were investigated. Drug encapsulation efficiency and particle size of the microspheres ranged from 52-78% w/w and 14-46 microm respectively. Interaction studies revealed that there were no drug-polymer interactions. The in vitro release profiles showed prolonged-release of the drug. In vitro release data showed a good fit with the Higuchi model, and indicated Fickian diffusion. No severe damage was found to the integrity of nasal mucosa after ex vivo experiments.

  13. 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.

  14. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    Directory of Open Access Journals (Sweden)

    Cristiane de Castro Pernet Hara

    2013-01-01

    Full Text Available The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

  15. Coupling Light from a High-Q Microsphere Resonator Using a UV-induced Surface Grating

    Science.gov (United States)

    Ilchenko, V. S.; Starodubov, D. S.; Gorodetsky, M. L.; Maleki, L.; Feinberg, J.

    2000-01-01

    High-Q microspheres with whispering-gallery modes have very narrow resonances that can be used for fiber-optic filters, ultra-compact narrow-linewidth lasers and optical/microwave oscillators. Whispering-gallery modes were previously excited in microspheres using evanescent optical fields. The necessary phase synchronism was obtained by adjusting the incident angle of input light beam (prism coupler) or adjustment of the waveguide propagation constant (fiber taper coupler). For many applications, however, bulky near-field couplers are undesirable. They compromise the symmetry and generate stray fields. Also, the control of coupling is crucial for the performance of microsphere resonators: in analogy with radio frequency circuits, the loading Q-factor should be less than the intrinsic Q-factor, Q(sub L) less than or equal to Q(sub O). Ideally one should combine a stable coupling element and a resonator into a single microsphere component.

  16. Preparation of gastro-resistant pellets containing chitosan microspheres for improvement of oral didanosine bioavailability

    Directory of Open Access Journals (Sweden)

    Patrícia Severino

    2012-06-01

    Full Text Available The purpose of this work was to introduce a new concept of coated pellets containing chitosan microspheres loaded with didadosine for oral administration, aiming at reducing the frequency of administration and improving the bioavailability by a suitable release profile. Chitosan microspheres were produced under fluidized bed, followed by extrusion and spheronization to obtain pellets with a mean diameter of about 1 mm. The pellets were then coated with Kollidon® VA64 and Kollicoat® MAE100P in water dispersion to depict a sustained release profile. Conventional hard gelatine capsules were loaded with these pellets and tested in vitro for their release profile of didadosine. Dissolution testing confirmed that chitosan microsphere pellets provides appropriate sustained release up to 2 h behavior for didanosine. Keywords: Didanosine, Pellets, Gastro-resistance, Coating, Microspheres, Chitosan

  17. Improved luminescence behavior of YVO4:Eu3+ hollow microspheres by Ca2+ doping

    Science.gov (United States)

    Jiu, Hongfang; Jiao, Hongqian; Zhang, Lixin; Jia, Wanbao; Huang, Changshui; Chang, Jianxia

    2015-07-01

    The YVO4:Eu3+/Ca2+ hollow microspheres were prepared via a urea-based homogeneous precipitation method in the presence of colloidal melamine formaldehyde resin (MF) microspheres as templates without heat treatment. Photoluminescence characteristics of YVO4:Eu3+ hollow microspheres are studied. X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) measurements were carried out to characterize their structural and luminescent properties. When compared with those of YVO4:Eu3+ hollow microsphere, the emissions of codoped sample with Ca2+ are greatly enhanced. The intensity of charge transfer absorption at 312 nm and its red emission have been greatly increased by codoping the Ca2+ ion into the YVO4:Eu3+ lattice.

  18. Alginate microspheres obtained by the spray drying technique as mucoadhesive carriers of ranitidine

    Directory of Open Access Journals (Sweden)

    Szekalska Marta

    2015-03-01

    Full Text Available The present study is aimed at formulation of alginate (ALG microspheres with ranitidine (RNT by the spray drying method. Obtained microspheres were characterized for particle size, surface morphology, entrapment efficiency, drug loading, in vitro drug release and zeta potential. Mucoadhesive properties were examined by a texture analyser and three types of adhesive layers - gelatine discs, mucin gel and porcine stomach mucosa. Microspheres showed a smooth surface with narrow particle size distribution and RNT loading of up to 70.9 %. All formulations possessed mucoadhesive properties and exhibited prolonged drug release according to the first-order kinetics. DSC reports showed that there was no interaction between RNT and ALG. Designed microspheres can be considered potential carriers of ranitidine with prolonged residence time in the stomach

  19. TERRA E SUA ASSOCIAÇÃO COM FERRO DEXTRAN NO DESEMPENHO DE LEITÕES EM ALEITAMENTO LAND AND ITS ASSOCIATION WITH IRON DEXTRAN IN THE PERFORMANCE OF PIGLETS

    Directory of Open Access Journals (Sweden)

    Sergito de Souza Cavalcanti

    2007-09-01

    Full Text Available

    Na central de Suínos de Goiás, no município de Senador Canedo, foi realizada esta pesquisa, onde se utilizou leitegada de quinze porcas Large White com a finalidade de se verificar o efeito da terra e de sua associação com ferro dextran no desempenho de leitões, aos 21 e 36 dias da idade. Os tratamentos utilizados foram os seguintes: T1 - 100 mg do ferro dextran via intramuscular no terceiro dia de vida dos leitões; T2 -50 mg de ferro dextran via intramuscular no terceiro dia de vida dos leitões mais 1,0 Kg de terra/dia do terceiro ao trigésimo quinto dia; T3 - 2,0 kg de terra/dia do terceiro ao trigésimo quinto dia de vida dos leitões. Observadas as condições em que foi realizado o experimento, conclui-se que: 1 a substituição de 50 mg de ferro dextran por 1,0 kg de terra/dia, do terceiro ao trigésimo quinto dia de vida dos leitões é tão eficiente quanto 100 mg de ferro dextran injetável intramuscularmente ao terceiro dia de vida; 2 o uso de 2,0 kg de terra diariamente do terceiro ao trigésimo quinto dia de vida dos leitões teve um desempenho inferior aos demais tratamentos.

    This research was developed in the Central Pig Farm in the county of Senador Canedo in Goiás State. Litters from 15 Large White sows were used to investigate the effect of feeding ground and its association with iron dextran to piglets from the third day of age. The evaluation of the effects of the treatments in the development of the piglets was done at 21 and 35 days of age. The treatments were as follow: T1 - 100 mg of iron dextran, via intramuscular, at the third day of age; T2 - 50 mg of iron dextran, via intramuscular, at the third day of age in association with 1.0 kg of ground, fed daily from the third to the 35th day of age; T3 - 2.0 kg of ground, daily, from the third to the 35th day of age. After observing

  20. Preparation of hollow core/shell microspheres of hematite and its adsorption ability for samarium.

    Science.gov (United States)

    Yu, Sheng-Hui; Yao, Qi-Zhi; Zhou, Gen-Tao; Fu, Sheng-Quan

    2014-07-09

    Hollow core/shell hematite microspheres with diameter of ca. 1-2 μm have been successfully achieved by calcining the precursor composite microspheres of pyrite and polyvinylpyrrolidone (PVP) in air. The synthesized products were characterized by a wide range of techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and Brunauer-Emmett-Teller (BET) gas sorptometry. Temperature- and time-dependent experiments unveil that the precursor pyrite-PVP composite microspheres finally transform into hollow core/shell hematite microspheres in air through a multistep process including the oxidation and sulfation of pyrite, combustion of PVP occluded in the precursor, desulfation, aggregation, and fusion of nanosized hematite as well as mass transportation from the interior to the exterior of the microspheres. The formation of the hollow core/shell microspheres dominantly depends on the calcination temperature under current experimental conditions, and the aggregation of hematite nanocrystals and the core shrinking during the oxidation of pyrite are responsible for the formation of the hollow structures. Moreover, the adsorption ability of the hematite for Sm(III) was also tested. The results exhibit that the hematite microspheres have good adsorption activity for trivalent samarium, and that its adsorption capacity strongly depends on the pH of the solution, and the maximum adsorption capacity for Sm(III) is 14.48 mg/g at neutral pH. As samarium is a typical member of the lanthanide series, our results suggest that the hollow hematite microspheres have potential application in removal of rare earth elements (REEs) entering the water environment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  2. In situ tuning of whispering gallery modes of levitated silica microspheres

    Science.gov (United States)

    Minowa, Yosuke; Toyota, Yusuke; Ashida, Masaaki

    2017-06-01

    We demonstrated the tuning of whispering gallery modes (WGMs) of a silica microsphere during optical levitation through the annealing process. We determined the annealing temperature from the power balance between the CO2 laser light heating and several cooling processes. Cooling caused by heat conduction through the surrounding air molecules is the dominant process. We achieved a blue shift of the WGMs as large as 1 \\%, which was observed in the white-light scattering spectrum from the levitated microsphere.

  3. Optical frequency conversion in silica-whispering-gallery-mode microspherical resonators.

    Science.gov (United States)

    Farnesi, D; Barucci, A; Righini, G C; Berneschi, S; Soria, S; Nunzi Conti, G

    2014-03-07

    High quality factor whispering-gallery-mode microresonators are ideally suited for nonlinear optical interactions. We analyze, experimentally and theoretically, a variety of χ((3)) nonlinear interactions in silica microspheres, consisting of third harmonic generation and Raman assisted third order sum-frequency generation in the visible. A tunable, room temperature, cw multicolor emission in silica microspherical whispering-gallery-mode microresonators has been achieved by controlling the cavity mode dispersion and exciting nonequatorial modes for efficient frequency conversion.

  4. Growth factor sequestration and enzyme-mediated release from genipin-crosslinked gelatin microspheres.

    Science.gov (United States)

    Turner, Paul A; Thiele, Jeffrey S; Stegemann, Jan P

    2017-11-01

    Controlled release of growth factors allows the efficient, localized, and temporally-optimized delivery of bioactive molecules to potentiate natural physiological processes. This concept has been applied to treatments for pathological states, including chronic degeneration, wound healing, and tissue regeneration. Peptide microspheres are particularly suited for this application because of their low cost, ease of manufacture, and interaction with natural remodeling processes active during healing. The present study characterizes gelatin microspheres for the entrapment and delivery of growth factors, with a focus on tailored protein affinity, loading capacity, and degradation-mediated release. Genipin crosslinking in PBS and CHES buffers produced average microsphere sizes ranging from 15 to 30 microns with population distributions ranging from about 15 to 60 microns. Microsphere formulations were chosen based on properties important for controlled transient and spatial delivery, including size, consistency, and stability. The microsphere charge affinity was found to be dependent on gelatin type, with type A (GelA) carriers consistently having a lower negative charge than equivalent type B (GelB) carriers. A higher degree of crosslinking, representative of primary amine consumption, resulted in a greater negative net charge. Gelatin type was found to be the strongest determinant of degradation, with GelA carriers degrading at higher rates versus similarly crosslinked GelB carriers. Growth factor release was shown to depend upon microsphere degradation by proteolytic enzymes, while microspheres in inert buffers showed long-term retention of growth factors. These studies illuminate fabrication and processing parameters that can be used to control spatial and temporal release of growth factors from gelatin-based microspheres.

  5. Microspheres for the Growth of Silicon Nanowires via Vapor-Liquid-Solid Mechanism

    Directory of Open Access Journals (Sweden)

    Arancha Gómez-Martínez

    2014-01-01

    Full Text Available Silicon nanowires have been synthesized by a simple process using a suitable support containing silica and carbon microspheres. Nanowires were grown by thermal chemical vapor deposition via a vapor-liquid-solid mechanism with only the substrate as silicon source. The curved surface of the microsized spheres allows arranging the gold catalyst as nanoparticles with appropriate dimensions to catalyze the growth of nanowires. The resulting material is composed of the microspheres with the silicon nanowires attached on their surface.

  6. In vitro-in vivo correlation of parenteral risperidone polymeric microspheres.

    Science.gov (United States)

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

    2015-11-28

    The objective of the present study was to determine whether an in vitro-in vivo correlation (IVIVC) can be established for polymeric microspheres that are equivalent in formulation composition but prepared with different manufacturing processes. Risperidone was chosen as a model therapeutic and poly(lactic-co-glycolic acid) (PLGA) with similar molecular weight as that used in the commercial product Risperdal® Consta® was used to prepare risperidone microspheres. Various manufacturing processes were investigated to produce the risperidone microspheres with similar drug loading (approx. 37%) but distinctly different physicochemical properties (e.g. porosity, particle size and particle size distribution). In vitro release of the risperidone microspheres was investigated using different release testing methods (such as sample-and-separate and USP apparatus 4). In vivo pharmacokinetic profiles of the risperidone microsphere formulations following intramuscular administration were determined using a rabbit model. Furthermore, the obtained pharmacokinetic profiles were deconvoluted using the Loo-Riegelman method and the calculated in vivo release was compared with the in vitro release of these microspheres. Level A IVIVCs were established and validated for the compositionally equivalent risperidone microspheres based on the in vitro release data obtained using USP apparatus 4. The developed IVIVCs demonstrated good predictability and were robust. These results showed that the developed USP apparatus 4 method was capable of discriminating PLGA microspheres that are equivalent in formulation composition but with manufacturing differences and predicting their in vivo performance in the investigated animal model. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Release of a Wound-healing Agent from PLGA Microspheres in a Thermosensitive Gel

    Science.gov (United States)

    2013-01-01

    release from microspheres incorporated in the gel was determined by UV spectrophotometry at 280 nm using an Eppendorf Biophotometer (Figure 2(b)). 2.2... spectrophotometry . Readings were obtained from samples determined in triplicates (mean ± standard errors). water ratio of the primary emulsion were prepared...microspheres for the delivery of DNA to human- derived macrophages and dendritic cells,” Journal of Controlled Release, vol. 76, no. 1-2, pp. 149–168

  8. Study on encapsulation of chlorine dioxide in gelatin microsphere for reducing release rate

    OpenAIRE

    Ci, Ying; Wang, Lin; Guo, YanChuan; Sun, Ruixue; Wang, Xijie; Li, Jinyou

    2015-01-01

    Objective: This study aims to explore the effects of encapsulation of chlorine dioxide in a hydrophilic biodegradable polymer gelatin to reduce its release rate. Methods: An emulsification-coacervation method was adopted. The characterizations of chlorine dioxide-gelatin microspheres were described. Using UV-vis spectrophotometer the λmax of chlorine dioxide was observed at 358 nm. The particle size and distribution of chlorine oxide-gelatin microspheres was measured by a dynamic light scatte...

  9. 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.

  10. Development of magnetoelectric CoFe2O4/poly(vinylidene fluoride) microspheres

    OpenAIRE

    R. Gonçalves; Martins, Pedro Libânio Abreu; Correia, D. M.; Sencadas, Vítor João Gomes Silva; J. L. Vilas; León, L. M.; Botelho, Gabriela; Lanceros-Méndez, S.

    2015-01-01

    Magnetoelectric microspheres based on piezoelectric poly(vinylidene fluoride) (PVDF) and magnetrostrictive CoFe2O4 (CFO), a novel morphology for polymer-based ME material, have been developed by an electrospray process. The CFO nanoparticles content in the (3-7 μm diameter) microspheres reaches values up to 27 wt.%, despite their concentration in the starting solution reaching values up to 70 wt.%. Additionally, the inclusion of magnetostrictive nanoparticles into the polymer spheres has no r...

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

    Directory of Open Access Journals (Sweden)

    Luisa Kelmer Côrtes de Barros Silveira

    2012-01-01

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

  12. Synthesis and photocatalytic properties of different SnO{sub 2} microspheres on graphene oxide sheets

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jia, E-mail: jojo.1125@hotmail.com [College of Science, Donghua University, Shanghai 201620 (China); Xue, Shaolin, E-mail: slxue@dhu.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); Xie, Pei, E-mail: peipeixie@sina.com [College of Science, Donghua University, Shanghai 201620 (China); Zou, Rujia, E-mail: rujiazou@dhu.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2016-07-15

    Highlights: • Different SnO{sub 2} microspheres were grown on GOs by hydrothermal method. • The morphology was influenced by volume ratio of ethanol and concentrations of precursor. • The shape of SnO{sub 2} microspheres looks like dandelion. • The photocatalytic property is strongly influenced by the SnO{sub 2} morphology on GOs. - Abstract: Different SnO{sub 2} microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO{sub 2} microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV–vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO{sub 2} microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO{sub 2} microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO{sub 2} microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

  13. Analysis of an optical biosensor based on elastic light scattering from diamond-, glass-, and sapphire microspheres

    OpenAIRE

    Murib, Mohammed Sharif; Tran, Anh Quang; De Ceuninck, Ward; Schöning, J.M.; Nesladek, Milos; SERPENGÜZEL, Ali; Wagner, Patrick

    2012-01-01

    Deoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q-factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere-based biosensors are considered as powerful candidates to achieve label-free recognition of single molecules due to the high sensitivity of thei...

  14. Preparation, Characterization and Adsorption Performance of a Novel Anionic Starch Microsphere

    OpenAIRE

    De, Yang; De, Wei; Sun; Wan

    2010-01-01

    Neutral starch microspheres (NSMs) were synthesized by an inverse microemulsion technology with epichlorohydrin as a crosslinker and soluble starch as starting material. Anionic starch microspheres (ASMs) were prepared from NSMs by the secondary polymerization with chloroacetic acid as the anionic etherifying agent. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and laser diffraction particle size analyzer were used to characterize the anionic starch micro...

  15. Synthesis of silver nanoparticles in the presence of diethylaminoethyl-dextran hydrochloride polymer and their SERS activity

    Science.gov (United States)

    Mikac, L.; Jurkin, T.; Štefanić, G.; Ivanda, Mile; Gotić, Marijan

    2017-09-01

    The silver nanoparticles (AgNPs) were synthesized upon γ-irradiation of AgNO3 precursor suspensions in the presence of diethylaminoethyl-dextran hydrochloride (DEAE-dextran) cationic polymer as a stabilizer. The dose rate of γ-irradiation was 32 kGy h-1, and absorbed doses were 30 and 60 kGy. The γ-irradiation of the precursor suspension at acidic or neutral pH conditions produced predominantly the silver(I) chloride (AgCl) particles, because of the poor solubility of AgCl already present in the precursor suspension. The origin of AgCl in the precursor suspension was due to the presence of chloride ions in DEAE-dextran hydrochloride polymer. The addition of ammonia to the precursor suspension dissolved the AgCl precipitate, and the γ-irradiation of such colourless suspension at alkali pH produced a stable aqueous suspension with rather uniform spherical AgNPs of approximately 30 nm in size. The size of AgNPs was controlled by varying the AgNO3/DEAE-dextran concentration in the suspensions. The surface-enhanced Raman scattering (SERS) activities of synthesized AgNPs were examined using organic molecules rhodamine 6G, pyridine and 4-mercaptobenzoic acid (4-MBA). The NaBH4 was used as SERS aggregation agent. The SERS results have shown that in the presence of synthesized AgNPs, it was possible to detect low concentration of tested compounds.

  16. Visualizing formation and dynamics of vacuoles in living cells using contrasting dextran-bound indicator: endocytic and nonendocytic vacuoles.

    Science.gov (United States)

    Voronina, Svetlana G; Sherwood, Mark W; Gerasimenko, Oleg V; Petersen, Ole H; Tepikin, Alexei V

    2007-12-01

    Here we describe a technique that allows us to visualize in real time the formation and dynamics (fusion, changes of shape, and translocation) of vacuoles in living cells. The technique involves infusion of a dextran-bound fluorescent probe into the cytosol of the cell via a patch pipette, using the whole-cell patch-clamp configuration. Experiments were conducted on pancreatic acinar cells stimulated with supramaximal concentrations of cholecystokinin (CCK). The vacuoles, forming in the cytoplasm of the cell, were revealed as dark imprints on a bright fluorescence background, produced by the probe and visualized by confocal microscopy. A combination of two dextran-bound probes, one infused into the cytosol and the second added to the extracellular solution, was used to identify endocytic and nonendocytic vacuoles. The cytosolic dextran-bound probe was also used together with a Golgi indicator to illustrate the possibility of combining the probes and identifying the localization of vacuoles with respect to other cellular organelles in pancreatic acinar cells. Combinations of cytosolic dextran-bound probes with endoplasmic reticulum (ER) or mitochondrial probes were also used to simultaneously visualize vacuoles and corresponding organelles. We expect that the new technique will also be applicable and useful for studies of vacuole dynamics in other cell types.

  17. Development of pH-sensitive Dextran Derivatives with Strong Adjuvant Function and Their Application to Antigen Delivery.

    Science.gov (United States)

    Yuba, Eiji; Uesugi, Shinya; Miyazaki, Maiko; Kado, Yuna; Harada, Atsushi; Kono, Kenji

    2017-08-04

    To achieve efficient cancer immunotherapy, the induction of cytotoxic T lymphocyte-based cellular immunity is necessary. In order to induce cellular immunity, antigen carriers that can deliver antigen into cytosol of antigen presenting cells and can activate these cells are required. We previously developed 3-methyl glutarylated dextran (MGlu-Dex) for cytoplasmic delivery of antigen via membrane disruption ability at weakly acidic pH in endosome/lysosomes. MGlu-Dex-modified liposomes delivered model antigens into cytosol of dendritic cells and induced antigen-specific cellular immunity. However, their antitumor effects were not enough to complete the regression of the tumor. In this study, antigen delivery performance of dextran derivatives was improved by the introduction of more hydrophobic spacer groups next to carboxyl groups. 2-Carboxycyclohexane-1-carboxylated dextran (CHex-Dex) was newly synthesized as pH-responsive dextran derivative. CHex-Dex formed stronger hydrophobic domains at extremely weak acidic pH and destabilized lipid membrane more efficiently than MGlu-Dex. CHex-Dex-modified liposomes were taken up by dendritic cells 10 times higher than MGlu-Dex-modified liposomes and delivered model antigen into cytosol. Furthermore, CHex-Dex achieved 600 times higher IL-12 production from dendritic cells than MGlu-Dex. Therefore, CHex-Dex is promising as multifunctional polysaccharide having both cytoplasmic antigen delivery function and strong activation property of dendritic cells for induction of cellular immunity.

  18. The formation of magnetic carboxymethyl-dextrane-coated iron-oxide nanoparticles using precipitation from an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Gyergyek, Sašo, E-mail: saso.gyergyek@ijs.si [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Primc, Darinka [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Plantan, Ivan [Lek Pharmaceuticals d.d., Mengeš (Slovenia)

    2015-03-01

    The formation of spinel iron-oxide nanoparticles during the co-precipitation of Fe{sup 3+}/Fe{sup 2+} ions from an aqueous solution in the presence of carboxymethyldextrane (CMD) was studied. To follow the formation of the nanoparticles, a mixture of the Fe ions, CMD and ammonia was heated to different temperatures, while the samples were taken, quenched in liquid nitrogen, freeze-dried and characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD) and magnetometry. The CMD plays a role in the reactions of the Fe ions' precipitation by partially immobilizing the Fe{sup 3+} ions into a complex. At room temperature, the amorphous material is precipitated. Then, above approximately 30 °C, the spinel nanoparticles form inside the amorphous matrix, and at approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles. The CMD bonded to the nanoparticles' surfaces hinders the mass transport and thus prevents their growth. - Highlights: • The carboxymethyl-dextrane coated iron-oxide nanoparticles were synthesized. • The carboxymethyl-dextrane significantly modifies formation of the spinel nanoparticles. • The spinel nanoparticles are formed inside the amorphous matrix. • At approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles.

  19. Intraoperative corneal thickness monitoring during corneal collagen cross-linking with isotonic riboflavin solution with and without dextran.

    Science.gov (United States)

    Oltulu, Refik; Şatirtav, Günhal; Donbaloğlu, Meryem; Kerimoğlu, Hürkan; Özkağnici, Ahmet; Karaibrahimoğlu, Adnan

    2014-11-01

    The aim of this study was to analyze and compare corneal thickness changes during corneal collagen cross-linking procedures performed with isoosmolar riboflavin solution with 20% dextran and without dextran in corneal ectatic diseases. The patients in this study were analyzed in 2 groups: group 1 receiving riboflavin solution containing 20% dextran and group 2 receiving dextran-free riboflavin solution. Corneal thickness measurements were obtained with ultrasonic pachymetry at 6 different time points: preoperatively and at 0, 15, 30, 45, and 60 minutes after epithelial removal and initiation of ultraviolet A irradiation. Twenty-seven eyes of 27 patients with progressive keratoconus were included in the study. In group 1 (n = 13), the mean preoperative thinnest pachymetric readings were 469.3 ± 8.5 μm, which decreased to 423.8 ± 8.9 μm after deepithelization and further decreased to 385.9 ± 10.9 μm at 15 minutes. The corneal thickness assumed a steady course at the 30-, 45-, and 60-minute measurements (378.9 ± 9.8 μm, 384.5 ± 10.5 μm, and 396.7 ± 9.4 μm, respectively). The initial change was statistically significant (P corneas.

  20. Physicochemical stability and in vitro bioaccessibility of ß-carotene nanoemulsions stabilized with whey protein-dextran conjugates

    Science.gov (United States)

    In this study, ß-carotene (BC)-loaded nanoemulsions encapsulated with native whey protein isolate (WPI) and WPI-dextran (DT, 5 kDa, 20 kDa, and 70 kDa) conjugates were prepared and the effects of glycosylation with various molecular weight DTs on the physicochemical property, lipolysis, and BC bioac...