Biocatalytic synthesis of highly ordered degradable dextran-based hydrogels

Ferreira, Lino; Gil, M.H.; Cabrita, António; Dordick, Jonathan S.

doi:10.1016/j.biomaterials.2004.11.051

Cited by 63 publications

(20 citation statements)

References 31 publications

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“…Dextran hydrogels can be obtained in various ways, based on either chemical or physical crosslinking. Dextran crosslinked with methacrylate (MA), hydroxyethylmethacrylate (HEMA) have been used as hydrogel implants, microspheres for scaffolds [139][140][141][142][143][144].…”

Section: Dextranmentioning

confidence: 99%

Water Soluble Polymers for Pharmaceutical Applications

2011

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Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1) synthetic and (2) natural. Drug polymer conjugates, block copolymers, hydrogels and other water soluble drug polymer complexes have also been explained. The general properties and applications of different water soluble polymers in the formulation of different dosage forms, novel delivery systems and biomedical applications will be discussed.

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Section: Dextranmentioning

confidence: 99%

Water Soluble Polymers for Pharmaceutical Applications

2011

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“…For that purpose we developed a photopolymerizable dextranbased hydrogels comprising either insoluble (RGD sequences) or soluble [vascular endothelial growth factor (VEGF 165 )] factors for the preferential differentiation of hESCs into the vascular lineage. Dextran-based hydrogels are biocompatible [7,8], biodegradable [9] and cellnonadhesive [7] which allows one to tailor its cell adhesiveness. The RGD peptide is the adhesive motif found in fibronectin, the earliest and most abundantly expressed extracellular matrix molecule during embryonic vascular development [10].…”

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confidence: 99%

Bioactive hydrogel scaffolds for controllable vascular differentiation of human embryonic stem cells

et al. 2007

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We propose a new methodology to enhance the vascular differentiation of human embryonic stem cells (hESCs) by encapsulation in a bioactive hydrogel. hESCs were encapsulated in a dextran-based hydrogel with or without immobilized regulatory factors: a tethered RGD peptide and microencapsulated VEGF 165 . The fraction of cells expressing vascular endothelial growth factor (VEGF) receptor KDR/Flk-1, a vascular marker, increased up to 20-fold, as compared to spontaneously differentiated embryoid bodies (EBs). The percentage of encapsulated cells in hydrogels with regulatory factors expressing ectodermal markers including nestin or endodermal markers including α-fetoprotein decreased 2 or 3 fold, respectively, as compared to EBs. When the cells were removed from these networks and cultured in media conditions conducive for further vascular differentiation, the number of vascular cells was higher than the number obtained through EBs, using the same media conditions. Functionalized dextran-based hydrogels could thus enable derivation of vascular cells in large quantities, particularly endothelial cells, for potential application in tissue engineering and regenerative medicine. 1-INTRODUCTIONDuring normal embryogenesis, human embryonic stem cells (hESCs) differentiate along different lineages in the context of complex three-dimensional tissue structures, where the extracellular matrix (ECM) and different growth factors play an important role in this process. The three-dimensional ECM provides structural support for higher level of tissue organization and remodelling [1]. Significant differences were found in the differentiation profile of ESCs when cultured in a three-dimensional (3D) versus two-dimensional (2D) system [2,3] or 3D scaffold system versus embryoid body (EB) system [4,5]. In this last case, mouse ESCs cultured within tantalum scaffolds differentiate at higher extent into hematopoietic cells than EBs [4], while hESCs cultured in alginate scaffolds express significantly more vascular markers than EBs [5]. Moreover, the culture of hESCs within 3D poly(α-hydroxy esters) scaffolds with media containing different growth factors induced their differentiation into 3D structures with || To whom reprint requests should be addressed at: Department of Chemical Engineering, E25-342 Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139. E-mail: rlanger@mit.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. [1,6]. However, these growth factors were supplied from outside the scaffold, and thus their activity may be affected by diffusion lim...

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“…Furthermore, the graft copolymers of acrylamide on different types of cellulose [8] revealed that various properties viz flocculation, solubility, thermal stability, binding strength, water retention and drag reduction effectiveness of the substrate increases. Besides these applications poly(acrylamide) has other multiple applications viz as polymer gel dosimeter [9], for water retention: owing to its high swelling capacity [10], in electrophoresis for separation of protein and DNA samples, as a model for drug delivery systems: for studying controlled drug release profiles [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

One pot synthesis and characterization of industrially important graft copolymer (GOH-g-ACM) by using peroxymonosulphate/ mercaptosuccinic acid redox pair

et al. 2009

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Guar gum-g-polyacrylamide is a graft copolymer which is used for many industrial applications. This paper outlines the details of synthesis of guar gum -gacrylamide by using potassium peroxymonosulphate/ mercaptosuccinic acid redox pair in an inert atmosphere and their characterization by infrared spectroscopy, UV analysis and study of swelling and thermal properties. Grafting characteristics: %G, %E, %C, %A and %H were determined by using Fanta's definition; rate of grafting was also calculated. On studying the effect of reaction conditions on grafting characteristics, it was found that the optimum concentration of peroxymonosulphate, mercaptosuccinic acid, hydrogen ion, acrylamide and guar gum for maximum % of grafting were 8.0×10 -3 , 3.2×10 -3 , 8.0×10 -3 , 16.0×10 -2 mol dm -3 and 60.0×10 -2 g dm -3 respectively. The optimum time duration and temperature of reaction were found to be 120 min and 40 °C respectively. During the study [H + ] variation showed prompt changes on grafting characteristics. It was found that after 310 °C the polyacrylamide grafted guar gum was thermally more stable than pure guar gum.

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Biocatalytic synthesis of highly ordered degradable dextran-based hydrogels

Cited by 63 publications

References 31 publications

Water Soluble Polymers for Pharmaceutical Applications

Water Soluble Polymers for Pharmaceutical Applications

Bioactive hydrogel scaffolds for controllable vascular differentiation of human embryonic stem cells

One pot synthesis and characterization of industrially important graft copolymer (GOH-g-ACM) by using peroxymonosulphate/ mercaptosuccinic acid redox pair

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