Preparation of microgel composite hydrogels by polymer post-crosslinking method

Qin, Xuping; Fang, Zhao; Feng, Shun

doi:10.3144/expresspolymlett.2011.44

Cited by 10 publications

(8 citation statements)

References 31 publications

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“…So, another method was used to determine the crosslinking bond character. Hydrogen bonds can be determined simply by 0.1 M NaOH solution . As shown in Table , all natural drying MC polymers were soluble in 0.1 M NaOH solution.…”

Section: Resultsmentioning

confidence: 99%

“…This natural drying polymer has soluble character, which can bring more convenience for studying the chemical reactions during the heating process. We have reported that the MC hydrogel was brittle and had low swelling ratio when the heating temperature was 90°C . So, the heating temperature range was chosen as 40°C–80°C.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, it can reduce the influence of water content on the hydrogel properties. However, in our previous study, when the MC polymer with low water content (about 30%) was heated at 90°C, the hydrogel was brittle due to the chemical reaction of the polymer chains . Low temperature can avoid the crosslinking of the polymer chains.…”

Section: Introductionmentioning

confidence: 93%

“…Hydrophobic polystyrene nanoparticles filler was also reported to enforce the mechanical properties of hydrogels . Hydrophilic microgels are also used as crosslinkers to prepare microgel composite (MC) hydrogels with excellent mechanical properties . MC hydrogels have an advantage that the microgel nanoparticles are prepared by almost the same organic monomers as the MC hydrogel matrix.…”

Section: Introductionmentioning

confidence: 99%

“…MC hydrogels can be prepared by the direct polymerization method using microgels containing double bonds as crosslinkers or the post‐crosslinking method using microgels containing hydroxymethyl groups as post‐crosslinkers . The preparation process of the post‐crosslinking method is relatively simple.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Preparation of microgel composite hydrogels by heating natural drying microgel composite polymers

Fang

Qin

Feng

et al. 2014

J of Applied Polymer Sci

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Acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid-based microgel composite (MC) hydrogels were prepared by heating natural drying MC polymers. It can reduce the influence of water content on the hydrogel properties. The natural drying MC polymer was swelling when the microgel content exceeded 0.5. It was soluble when the microgel content was 0.25, which was used to investigate the heating conditions. Under 50 C, MC hydrogels was obtained and hydrogen bonding was the reason for their formation. The tensile strength increased and the tensile elongation decreased as the heating time increased. When the heating time was 3 h, the tensile elongation decreased, as the heating temperature increased from 50 C to 80 C. However, the tensile strength increased first and then decreased. Under 60 C, the MC hydrogel had a high tensile strength of 155.3 kPa and a high tensile elongation of 313.3%. The more crosslinking density and the formation of covalent crosslinking bonds between the microgel particles and hydrogel matrix led to an increase in the tensile strength. However, the excess crosslinking of the polymer chains under high temperature could reduce the tensile strength. The tensile strength increased as the microgel content increased to 0.75 and then decreased as microgel content further increased.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Preparation of microgel composite hydrogels by heating natural drying microgel composite polymers

Fang

Qin

Feng

et al. 2014

J of Applied Polymer Sci

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Macroscopic Microgel Networks

Hoare

2012

Hydrogel Micro and Nanoparticles

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Injectable Gel Scaffold Based on Biopolymer Microspheres via an Enzymatic Reaction

Tan

Fan

et al. 2014

Adv Healthcare Materials

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and biological properties, we hypothesize that the microphasesegregated DN concept could be applicable for developing injectable microsphere-based gel scaffolds with biological functionalities. It consists of two networks: a densely cross-linked biopolymer microspheres network (skeleton) and a sparsely cross-linked ductile biopolymer network. One can expected two advantages of this microsphere-based DN gel. First, microspheres incorporated at higher composition ratio can potentially increase strength of the DN gel due to their higher stiffness. Second, because GFs were encapsulated not in the ductile network but in microspheres, the GFs were expected to function better in this microsphere-based DN gel than in normal DN hydrogels. Importantly, unlike most microspheres that are chemically inert, our biopolymer microspheres would have residual functionalities that allow for further bioconjugation of a ductile network.Our strategy is to use heparin as the microspheres substrate and chitosan as the ductile network, respectively. In this system, heparin microspheres with higher composition ratio can potentially increase strength of the DN gel, while chitosan solution as a liquid phase can provide the injection. Heparin and chitosan are proteoglycans or glycosaminoglycans (GAGs), as highly charged polyelectrolytes, which could be additionally crosslinked by electrostatic interactions. Heparin is a negatively charged GAG, which is composed of repeated disaccharide units of alternating glucosamine and glucuronic residues heterogeneously modifi ed by carboxyl groups and N -or O -linked sulfate. Most importantly, the ability of heparin to sequester and stabilize GFs due to specifi c affi nity GF-immobilization has been exploited in the production of microspheres that can mediate cell proliferation and differentiation. [ 10 ] Chitosan is a positively charged polysaccharide composed of repeated glucosamine and N -acetylglucosamine, which also has been widely applied in drug delivery, gene therapy, and tissue engineering. [ 11 ] Mechanism for the formation of the microspheres, as well as for the formation of a 3D gel scaffold, is proposed in Scheme 1 . Our method for preparing heparin microspheres and gel scaffolds relies on in situ cross-linking of heparin with built-in fi brin-mimicking peptide of CTIGEGQQHHLGGAKQAGDV containing Lys and Gln functionalities. This peptide derived from the transglutaminase factor XIIIa (FXIIIa) crosslinking site of fi brin, with an additional N -terminal cysteine residue. [ 12a ] The peptides would couple and form covalent isopeptide bridges between Gln and Lys by enzymatic catalysis of the FXIIIa. [ 12 ] To do this, chemical modifi cations were employed to selectively introduce complementary reactive peptides to maleimide-functionalized heparin and chitosan via the Michael-type addition, respectively. Subsequently, peptide-functionalized heparin was formed microspheres via the inverse emulsion cross-linking Macromolecular microspheres have become an important structure in polymeric materials...

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Preparation of microgel composite hydrogels by polymer post-crosslinking method

Cited by 10 publications

References 31 publications

Preparation of microgel composite hydrogels by heating natural drying microgel composite polymers

Preparation of microgel composite hydrogels by heating natural drying microgel composite polymers

Macroscopic Microgel Networks

Injectable Gel Scaffold Based on Biopolymer Microspheres via an Enzymatic Reaction

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