Papers by Keyword: Alginate

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Authors: Dae Hwan Park, Won Seok Choi, Sean Hyuck Yoon, Jung Soo Shim, Chul Hong Song
Abstract: Alginate, which is isolate from brown seaweed, a bioabsorbable long chain polysaccharides of guluronic acid and mannuronic acid. The authors produced alginate, fibroblastgrowth- factor mixed alginate and alginate-collagen complex as a disc form. For study of wound healing, full thickness skin defects were made on the dorsal area of the animal model. And then alginate, fibroblast-growth-factor mixed alginate, alginate-collagen complex, vaseline gauze as control were applied on the wound and evaluated grossly and histopathologically. For biocompatibility test, alginate and alginate-collagen complex discs were implanted on back of New Zealand white rabbits. And we measured size of wound healing, size of wound epithelization, size of wound contracture at 5, 10, 15, 20, and 25 days. Four weeks after implantation, implanted animals were examined immunologically against alginate and collagen. Alginate and FGF-mixed alginate, alginate-collagen complex group showed statistically higher percentage of wound contraction and wound healed than control group(p<0.05) Alginate-collagen complex group and FGF-mixed alginate group showed statistically higher percentage of wound healed than alginate group. In conclusion, high-purified alginate from seaweeds by our purification method, has the ability of wound healing and addition of FGF or collagen increase the ability of alginate, it shows the possibility of alginate as dermal substrate.
Authors: Hua'an Zhang, Lin Sun, Wei Wang, Xiao Jun Ma
Abstract: Fibrosis caused by the host response to long-term transplanted microcapsules and the limitation of traditional L929 cell model for biocompatibility testing inspire the development of an assay of biocompatibility based on macrophage behavior. In this paper, the human monocytic cell line THP-1 was utilized for biocompatibility evaluation of microcapsule materials. The cell viability and secretion of nitric oxide (NO) and cytokines served as index of biocompatibility were assayed. It was found that the evaluated microcapsule materials had no effect on the stimulation of NO and cytokines secretion, which meant that these materials were biocompatible. Furthermore, it suggests the THP-1 cell a convenient in vitro experimental model that might be useful for long-term predictions of material biocompatibility.
Authors: Jie Zhou, Yuan Lu Cui, Yun Qi
Abstract: Glutaraldehyde cross-linked chitosan coated-alginate microspheres were prepared to improve site specificity in colonic drug delivery system. Microspheres were characterized by microscopic image analysis, DSC and IR to study the formation of microspheres structure as well as the chemical interactions between drug and polymer. Microscope observation showed good spherical and homogeneous of microspheres. The glutaraldehyde cross-linked microspheres could produce Schiff base reaction and decrease chitosan hydrogen bonding interaction with mucous membrane. The drug loading of chitosan coated-alginate microspheres reached 43% and in vitro release properties of microspheres without cecal contents reached 20.96% after 12 h. The release profiles indicated that microsphere has a satisfactory sustained release behavior. Glutaraldehyde cross-linked chitosan coated-alginate microspheres have a great potential use in drug delivery system.
Authors: B. Obradović, A. Osmokrović, B. Bugarski, D. Bugarski, G. Vunjak-Novaković
Abstract: Alginate was shown to be a suitable support for entrapment and cultivation of chondrocytes and bone marrow stromal cells, which under appropriate in vitro conditions synthesized cartilaginous components. The main limitation in these cultures may be low rates of mass transport through the alginate matrix governed by diffusion. In this study, we have designed and utilized a bioreactor system based on a packed bed of alginate beads with immobilized chondrogenic cells. Continuous medium perfusion provided convective mass transport through the packed bed, while small diameters of beads (2.5 mm and down to 500 μm) ensured short diffusion distances to the immobilized cells. During up to 5 weeks of cultivation, the cells synthesized extracellular matrix components merging beads together and indicating potentials of this system for precise regulation of the cellular microenvironment in cartilage tissue engineering.
Authors: D. Bugarski, B. Obradović, M. Petakov, G. Jovčić, N. Stojanović, B. Bugarski
Abstract: Alginate is currently being employed and explored for a broad range of biomedical and biotechnology applications, due to its biodegradability and simple procedure for cell immobilization. However, cell immobilization was mostly aimed for immunoisolatory and biochemical processing applications and far less is known about potentials of alginate as a substrate for tissue formation. In the present work, isolation, immobilization and cultivation procedures of murine bone marrow stromal cells (BMSC) were studied and standardized in order to establish the alginate-bioreactor culture system for chondrogenic and/or hematopoiesis-supportive tissue progression. Two techniques for cell immobilization based on alginate were investigated: entrapment within gel matrix using electrostatic droplet generation and simple cell adsorption onto gel surfaces. Alginate gels in forms of microbeads and discs with immobilized culture expanded BMSC were cultivated for up to 30 days and analyzed for surface properties, cell concentration, viability, and differentiation.
Authors: Bon Kang Gu, Sang Jun Park, Min Sup Kim, Chun Ho Kim
Abstract: In this study, we developed the porous alginate (AL) scaffolds with modified pores size and distributions to actively control tissue regeneration. An addition of 5 and 10% (v/v) butanol to AL solution was effective to control pores structures of AL scaffolds. Especially, increased amount of butanol induced that proportion of smaller pores (size of around 5~10 μm) on AL scaffolds increased. Using swelling kinetics analysis, we confirmed that micro pore modified AL scaffolds show faster swelling rate than pristine scaffolds. During in vitro study, the enhanced viability and proliferation of human dermal fibroblasts (HDFs) were observed by the pore size and distribution from micro pore modified AL scaffolds. However, AL scaffolds added 10 % butanol with excessive proportion of smaller pores induced the decreased viability of HDFs for 7 days. From our results, AL scaffolds with modified pores structures represent a potential implants to control biological in vitro and in vivo functions in a variety of tissue engineering.
Authors: Shi Jun Wei, Meng Zhang, Lei Li, Lu Lu
Abstract: Multi-membrane hydrogels are newly promising carriers in biomedical fields for their gentle gel condition and excellent biocompatibilities. In this study we focused on the dual control release property of alginate-based onion-like multi-membrane hydrogels hybrid with polylactic acid microspheres. The results indicated that the PLA microspheres evenly distributed in each of the hydrogel membranes. And the drug delivery in physiological saline is well controlled which can be promising in transport drugs, genes, protein, etc.
Authors: An Na Wang, Li Gen Wu, Lin Lu Jia, Xiu Ling Li, Yu Dan Sun
Abstract: Tea polyphenol loaded alginate-chitosan microspheres were prepared by ionic gelation method for controlling tea polyphenol release by using various combinations of chitosn and Ca2+ as cation and alginate as anion.Scanning electron microscopy were used to investigate the surface characteristics of tea polyphenol loaded microspheres. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of tea polyphenol. The main advantage of this system is that all procedures used were performed in aqueous medium which may preserve the tea polyphenol bioactivity. At pH7.4, the amounts of tea polyphenol released increased significantly as compared to those released at pH1.2. It is evident that the rate of tea polyphenol release could be controlled by changing the chitosan and the calcium chloride concentrations.
Authors: Yuan Gang Liu, Hong Hao Mao, Shi Bin Wang, Qing Qing Sun
Abstract: Alginate–chitosan nanocapsules (Alg-CS NCs) were prepared by a two-stage process. The NCs were loaded with two low molecular drugs-tegafur and Mitoxantrone Hydrochloride(DHAD). Results revealed that these two drugs exhibited different drug loading and release characteristics. The drug loading and encapsulation efficiency of tegafur (<1%) were both lower than those of DHAD with the drug loading at about 20%~60% and encapsulation efficiency over 90%. However, tegafur showed a visible burst release phenomenon and the cumulative release rate of tegafur was much higher than that of DHAD.
Authors: Hu Lin Jiang, Rohidas B. Arote, Ji Shan Quan, Mi Kyong Yoo, You Kyoung Kim, In Yong Kim, Zhong Shan Hong, Hong Gu Lee, Xun Jin, Yun Jaie Choi, Chong Su Cho
Abstract: Thiolated polymers have been studied by many researchers because of the mucoadhesive properties of thiol group. Alginate is a natural and biocompatible polymer that has been widely used in drug delivery. In this study, thiolated chitosan microspheres (TCMs) were prepared by ionic gelation process with tripolyphosphate and then, the bovine growth hormone (BGH) was loaded as a model drug. Finally, the BGH-loaded TCMs (BTCMs) were coated with alginate to improve the stability in gastrointestinal (GI) track. The alginate-coated BTCMs (ABTCMs) were observed as spherical shapes. The average particle sizes of ABTCMs were 6.97±0.55 -m and the sizedistribution was shown uniformly. Release of BGH from ABTCMs was decreased by coating with alginate and increased rapidly with the change in medium pH from 1.2 to 7.4. Results indicate that the ABTCMs have a potential as a drug carrier for oral drug delivery.
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