Papers by Keyword: Dextran

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Authors: T. Yamamoto, Shunsuke Fujibayashi, Naoki Nakajima, Hajime Sugai, Suong Hyu Hyon, Takashi Nakamura
Abstract: A new biodegradable adhesive(LYDEX) which is based on Schiff base formation had developed. LYDEX is easy to control the setting time and degradation speed and it has no risk of infection. In the previous study, LYDEX showed high bonding strength and low cytotoxicity in vitro[1]. In the present study, good bone repair was seen in rat bone defect models, especially in rapidly degrading type. On the other hand, slowly degrading type kept its shape longer without excessive inflammation. In rabbit critical defect model with hydroxyapatite granules (HAs), more newly formed bone was seen in rapidly degrading group and hydroxyapatite group, in 3weeks. In 6weeks, more new bone was seen in slowly degrading type group, whereas, almost no new bone was seen in deep area of the fibrin group, in 12weeks. Direct bonding between HAs and bone was seen in HA group and LYDEX groups. These findings suggest that LYDEX with hydroxyapatite granules can be a promising bone substitute.
Authors: Maria Dumitraşcu, Mădălina Georgiana Albu, Marian Vîrgolici, Cătălin Vancea, Viorica Meltzer
Abstract: In the past years an increased interest to create new polymeric blends with application in the medical area for development of new types of biomaterials has appeared. Electron beam irradiation is well known as a method of producing important changes in polymer structure, being an alternative to chemical synthesis of biomaterials based on polymeric materials. The aim of the present study was to investigate the behaviour of some polyvinylpyrrolidone-dextran (PVP/DEX) blends under electron beam irradiation. Aqueous solutions of PVP with molecular weights of 360 000 Da (PVP 360), 40 000 Da (PVP 40), and DEX with molecular weight of 500 000 Da (DEX), were mixed as to obtain 50:50 blends of PVP40/DEX and PVP360/DEX. The obtained blends were irradiated with electron beam at different radiation doses and after irradiation treatment were processed by freeze-drying. PVP/DEX blends were characterized by infrared spectroscopy (FT-IR) and thermal analysis. The analyses were conducted in order to establish the relation between radiation dose and changes of structural and thermal properties.
Authors: Paramaporn Chiewpattanakul Kaewmanee, Benjamas Wongsatayanon, Alain Durand
Abstract: The dextran-covered poly (lactic acid) (PLA) polymeric nanoparticles were prepared by a nanoprecipitation process for the encapsulation of monocaprin (MC) or monolaurin (ML). The concentration of PLA/MC or ML was varied to evaluate the best condition for preparation. The miscibility of various PLA/MC or ML blends was studied using differential scanning calorimetry. The result showed that at concentrations of 50/50 wt/wt, the PLA/ML blend was partly miscible and the nanoparticle suspension produced large amounts of macroscopic aggregates after nanoprecipitation. Conversely, the miscibility of PLA/MC blends progressively increased with increasing amounts of PLA. Therefore, the best concentration to encapsulate the MC was the PLA/MC 90/10 (wt/wt), according to the miscibility results.
Authors: Jun Qi Tang, Ning Zhang, Shi Qing Man
Abstract: A green approach to synthesize stable gold nanoparticles (AuNPs) employing dextran as a reducing and stabilizing agents at different temperature was described. The obtained dextran-coated gold nanoparticles (Dex-AuNPs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and UV-Vis spectroscopy. The average diameter of those resultant AuNPs at boiling bath was 12.1 nm with a relative standard deviation of less than 5.6%. UV–Vis spectra showed the presence of a surface plasmon band at 518 nm. These results suggested that the prepared Dex-AuNPs complexes had excellent monodispersity and acted as a candidate for further biomedical application.
Authors: Qing Wang, Xiao Wang, Qing Song Zou, Yuan Yuan Pu, Shan Chen
Abstract: The cells of Leuconostoc mesenteroides were immobilized for dextran producing and response surface methodology based on experimental designs were applied to optimize the medium for maximum yield. Eight different medium components were examined for their significance on dextran production using Plackett-Burman factorial design. Na2HPO4, CaCl2 and sodium citrate were found to have significant effect on dextran production. The combined effect of these nutrients on dextran production was studied using central composite design. The optimal concentration of variables for maximum dextran production were 0.245 g/100mL of Na2HPO4, 0.05 g/100mL of CaCl2 , 0.2084 g/100mL of sodium citrate. The maximum concentration of dextran obtained at 24 h by predicted model was 1.88045 mg/mL that was in perfect agreement with the experimental determined value 1.85395 mg/mL. Dextran yield was over 376% higher as compared to original medium which gave 0.38956 mg/mL of dextran.
Authors: Xiao Hua Geng, Liu Yuan, Xiu Mei Mo
Abstract: In our previous study, oxidized dextran/amino gelatin (ODex/MGel) self-crosslinking hydrogels have been successfully prepared. Though their potential applications as in situ forming scaffolds for tissue engineering have been verified, the subcellular porosities of hydrogel networks which were induced by the intensity chemical crosslinking still pose a barrier for cells migration and proliferation within the hydrogels. The objective of this study was to develop an approach to accelerate cellular remodeling by preparing semi-interpenetrating networks (semi-IPNs) composed of ODex, MGel, and sodium hyaluronic (HA). Results showed that the addition of HA at the concentrations of 0.09% and 0.18% can greatly promote pre-osteoblast (MC3T3-E1) cells spreading throughout the ODex/MGel hydrogel networks. Therefore, these semi-IPNs hydrogels could be useful matrixes for cell transplantation in a variety of tissue engineering applications.
Authors: He Lei, Guo Liang Zhang
Abstract: Dextran catches increasing attentions as a drug carrier because of its biocompatibility, biodegradability and ease of modification. In this study, we synthesized the derivated dextran by grafting with 1-(3-aminopropyl) imidazole. The dextran-based nanoparticles with sizes of 1H NMR, SEM, AFM and Zetasizer.
Authors: Chang Shu Tsai, Wei Chung Liu, Hong Yi Chen, Wei Chun Hsu
Abstract: In the aspect of biomedical diagnosis, magnetic nanoparticle can be used as drug carrier and MRI/ SPECT/ PET contrast agents. Magnetic fluid hyperthermia is one of the most important cancer therapies. Magnetic nanoparticles display their unique features as heating mediators for hyperthermia. In this study, Fe3O4 magnetic nanoparticle was prepared by using chemical co-precipitation method. Tc-99m pertechnetate with Fe3O4 magnetic nanoparticles is prepared by using magnet adsorption method. An attempt was also made to evaluate the application in the field of magnetic targeted drug delivery and radioactive targeted cancer treatment in the future. In this work, preparation and characterization of non-polymer and polymer (dextran) coated Fe3O4 magnetic nanoparticles labeled with technetium-99m pertectnetate were evaluated and served as precursors study. The Tc-99m labeling efficiency of in-house Fe3O4 magnetic nanoparticles (MNP) and commercial kit were ca.98.4 % and 85% (n=5), under the same conc. of 6mM, 0.1 ml of SnCl2·2H2O, respectively. The Tc-99m labeling efficiency of magnetic nanoparticles with its dextran-coated was ca. 58.2% (n=5) at the same conc. and volume of SnCl2·2H2O. The in-vitro stabilities of the 3 kinds of magnetite magnetic fluids were higher than 96.0% (n=5) during 2 hours. The reducing agent of SnCl2·2H2O plays a key role due to its reducing ability for Tc-99m pertechnetate. The optimal reaction time of SnCl2·2H2O with Tc-99m is better under 1 hour. In conclusion, the Fe3O4 magnetic nanoparticle labeled with Tc-99m pertechnetate has shown good qualities for its labeling efficiency and stability. It may be feasible preliminary to utilize in the application of magnetic targeted drug delivery of bio-medicine.
Authors: Wan Ting Niu, Lu Yao Zhang, Min Pan, Yu Quan Chen
Abstract: Superparamagnetic iron oxide (SPIO) nanoparticles were used more and more universally in biomedical research recently. In order to develop a suitable immuno-magnetic probe which can be applied in antigen-antibody based immunoassay, such as tumor marker or cardiovascular marker detection, SPIO capped by dextran was synthesized with chemical coprecipitation method. With sodium periodate method, hydroxyl groups of dextran were oxidated to aldehyde groups, thus conjugated with antibodies by covalent bonds. Western blot pattern illustrated that structure integrity of the most antibodies was kept well, harmful influence given by oxidation of conjugation was very finite. Both immune reactivity and antigenicity of antibodies in the SPIO based immunoprobes were retained effectively. This probe has a potentially application in SPIO based novel suspension array for its superparamagnetic property that can be separated under gradient magnetic field.
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