Simultaneously physically and chemically gelling polymer system utilizing a poly(NIPAAm-co-cysteamine)-based copolymer

Stephanie A. Robb, Bae Hoon Lee, Ryan McLemore, Brent Vernon

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

The objective of this work was to create an in situ physically and chemically cross-linking hydrogel for in vivo applications. N-Isopropylacrylamide (NIPAAm) was copolymerized with N-acryloxysuccinimide (NASI) via free radical polymerization. Poly(NIPAAm-co-NASI) was further modified to obtain poly(NIPAAm-co-cysteamine) through a nucleophilic attack on the carbonyl group of the NASI by the amine group of the cysteamine. Modification was verified by nuclear magnetic resonance. In addition to thermoresponsive physical gelling due to the presence of NIPAAm, this system also chemically gels via a Michael-type addition reaction when mixed with poly(ethylene glycol) diacrylate. The presence of both physical and chemical gelation resulted in material properties that are much improved compared to purely physical gels. The chemical gelation time of the copolymers was not significantly affected by the amount of thiol present due to the increased pKa of the copolymer containing more thiols. In addition, the swelling of the copolymers was highly dependent on the temperature and thiol content. Last, the rate of nucleophilic attack in the Michael-type addition reaction was shown to be highly dependent on pH and on the mole ratio of thiol to acrylate. Due to the improved mechanical properties, this material may be better suited for long-term functional replacement applications than other thermosensitive physical gels. With further development and biocompatibility testing, this material could potentially be applied as a temperature-responsive injectable biomaterial for functional embolization.

Original languageEnglish (US)
Pages (from-to)2294-2300
Number of pages7
JournalBiomacromolecules
Volume8
Issue number7
DOIs
StatePublished - Jul 2007

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Cysteamine
Sulfhydryl Compounds
Polymers
Addition reactions
Gels
Copolymers
Gelation
Materials testing
Free radical polymerization
Materials Testing
Biocompatibility
Biomaterials
Hydrogels
Polyethylene glycols
Temperature
Swelling
Hydrogel
Amines
Materials properties
Biocompatible Materials

ASJC Scopus subject areas

  • Organic Chemistry
  • Biochemistry, Genetics and Molecular Biology(all)
  • Polymers and Plastics
  • Materials Chemistry

Cite this

Simultaneously physically and chemically gelling polymer system utilizing a poly(NIPAAm-co-cysteamine)-based copolymer. / Robb, Stephanie A.; Lee, Bae Hoon; McLemore, Ryan; Vernon, Brent.

In: Biomacromolecules, Vol. 8, No. 7, 07.2007, p. 2294-2300.

Research output: Contribution to journalArticle

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