Comparison of two carboxylate‐activating agents for the modification of a synthetic heparinoid polyelectrolyte

Sederel, L.C.; Does, L. van der; Beugeling, T.; Feijén, Jan; Bantjes, A.; Kim, S. W.

doi:10.1002/pol.1983.130210101

Cited by 7 publications

(3 citation statements)

References 12 publications

(5 reference statements)

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“…Hydrogel synthesis follows the same chemical route that has been well-documented in carbodiimide chemistry [7,25]. Basically, the synthesis of CMC-and Hyal-based hydrogels exploits the formation of an amide bond between the carboxylate groups of the polymer chains and the primary amine groups of 1,3 diaminopropane (DAP), which is added to the polymer aqueous solution as the cross-linking agent of the polymer chain.…”

Section: Hydrogel Synthesismentioning

confidence: 99%

“…In order to verify how the hydrogels respond to the variation of an applied stress, a four-step dynamic stress sweep test was performed. The measurement is carried out by increasing (step 1) and decreasing (step 2) the oscillation twice, through the addition of a further increasing step (step 3) and decreasing step (step 4) [7,25]. The sample is subjected cyclically to the same applied stress (increasing and decreasing steps).…”

Section: Mechanical Propertiesmentioning

confidence: 99%

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Polysaccharide-Based Hydrogels: The Key Role of Water in Affecting Mechanical Properties

Pasqui¹,

Cagna²,

Barbucci³

2012

Polymers

162

100

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Different hydrogels were prepared starting from natural or semi-synthetic polysaccharides (carboxymethylcellulose, hyaluronic acid and chitosan) which were cross-linked by the addition of a cross-linking agent chosen according to the chemical groups present along the polymer chains. The cross-linking reaction allows for the formation of a three-dimensional network made of covalent bonds between the polymer chains, which is stable under physiological conditions. The presence of a substantial amount of water within the polysaccharide matrices makes such systems unique among hydrophilic gels. Water itself is responsible for some of their peculiar characteristics, one of which is their injectability which makes these hydrogels suitable for using as matrices for mini-invasive surgery and localized therapy.

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Section: Hydrogel Synthesismentioning

confidence: 99%

Section: Mechanical Propertiesmentioning

confidence: 99%

Polysaccharide-Based Hydrogels: The Key Role of Water in Affecting Mechanical Properties

Pasqui¹,

Cagna²,

Barbucci³

2012

Polymers

162

100

View full text Add to dashboard Cite

show abstract

“…The Hyal and CMC hydrogels were synthesized following the same chemical route, i.e. by exploiting the EDC chemistry: 24 basically, an amide bond between the carboxylic groups of the polysaccharides and the primary amine of 1,3-diaminopropane (DAP), the crosslinking agent, is formed thanks to the presence of EDC. The polymer was first dissolved in deionized water at a concentration of 1.5% w/vol.…”

Section: Methodsmentioning

confidence: 99%

Inter-penetrating hydrogels (IPHs) as a new class of injectable polysaccharide hydrogels with thixotropic nature and interesting mechanical and biological properties

Barbucci

Giardino²,

Cagna

et al. 2010

Soft Matter

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Hydrogels are important and very promising materials for biomedical applications, such as cell scaffolds and drug delivery systems. A new class of injectable materials was obtained by mixing polysaccharide chemically crosslinked hydrogels. The mixing was performed by exploiting the thixotropic behaviour of the polysaccharide hydrogels: in other words they were passed through a syringe to subject them to shear stress and render them fluid, then they were mixed together in the fluid state. Once the material regained its consistency, a new hydrogel was obtained, called an interpenetrating hydrogel (IPH), containing both the native hydrogels. This new class of materials showed different physical-chemical, mechanical and biological properties from the native hydrogels utilized for the mixing. The hydrogels taken into consideration were: negatively charged carboxy methyl cellulose (CMC) and hyaluronic acid (Hyal), uncharged guar gum (GG), and chitosan (CHT), which bore positive charges at physiological pH. The IPHs obtainedi.e. CMC-CHT, CMC-GG and CMC-Hyal -were characterized by means of Fourier transform infrared spectroscopy (FT-IR) and swelling measurements. The mechanical properties of the IPHs were investigated by rheometric analyses, while their morphology was studied by scanning electronic microscopy (SEM). The biological performance of the IPHs was evaluated using fibroblasts (NIH 3T3 cell line) and compared with that of the native hydrogels.

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Synthesis and characterization of polystyrene–poly(ethylene oxide)–heparin block copolymers

Vulić

Okano

Kim

et al. 1988

J. Polym. Sci. A Polym. Chem.

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SynopsisA procedure for the preparation of new block copolymers composed of a hydrophobic block of polystyrene, a hydrophilic spacer-block of poly(ethy1ene oxide) and a bioactive block of heparin was investigated. Polystyrene with one amino group per chain was synthesized by free radical oligomerhtion of styrene in dimethylformamide, using 2-aminoethanethiol as a chain transfer agent. This amino group was used in the coupling reaction with amino-telechelic poly(ethy1ene oxide) to produce an AB type diblock copolymer with one amino group per polystyrene (PSt)-poly(ethy1ene oxide) (PEO) chain. The amino-semitelechelic oligestyrene was converted into the isocyanatrsemitelechelic oligo-styrene using toluene 2,4diisocyanate and subsequent coupling with H,N-PEO-NH, afforded AB type block copolymers with terminal amino groups.The coupling of PSt-PEO-NH, with heparin was performed in a DMF-H,O mixture, first by activating the heparin carboxylic groups with EDC at pH 5.1-52 and subaequently reading the activated carboxylic groups with the amino groups of the PSt-PEO-NH2 at pH 7.5. Depending on the molecular weights of the diblock copolymer used 25-29% w/w heparin was incorporated. Thew polymers will be further evaluated for their blood-compatibility.

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Comparison of two carboxylate‐activating agents for the modification of a synthetic heparinoid polyelectrolyte

Cited by 7 publications

References 12 publications

Polysaccharide-Based Hydrogels: The Key Role of Water in Affecting Mechanical Properties

Polysaccharide-Based Hydrogels: The Key Role of Water in Affecting Mechanical Properties

Inter-penetrating hydrogels (IPHs) as a new class of injectable polysaccharide hydrogels with thixotropic nature and interesting mechanical and biological properties

Synthesis and characterization of polystyrene–poly(ethylene oxide)–heparin block copolymers

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