Designing alginate hydrogels to maintain viability of immobilized cells

Hyun Joon Kong, Molly K. Smith, David J. Mooney

Research output: Contribution to journalArticle

Abstract

Hydrogel-forming materials have been widely utilized as an immobilization matrix and transport vehicle for cells. Success in these applications is dependent upon maintaining cell viability through the gel preparation process. We hypothesized that the high viscosity of pre-gelled solutions typically used in these applications may decrease cell viability due to the high shear forces required to mix cells with these solutions. Further, we proposed this harmful effect could be mediated by decreasing the molecular weight (Mw) of the polymer used to form the gel, while maintaining its gel-forming ability. To investigate this hypothesis, alginate was used as model system, as this copolymer consists of cross-linkable guluronic acid (G) blocks and non-cross-linkable blocks. Decreasing the Mw of alginate using irradiation (e.g., irradiating at dose of 2Mrad) decreased the low shear viscosity of 2% (w/w) pre-gelled solutions from 1000 to 4cP, while maintaining high elastic moduli, once cross-linked to form a gel. Importantly, the immobilization of cells with these polymer hydrogels increased cell viability from 40% to 70%, as compared to using high Mw polymer chains to form the gels. Furthermore, the solids concentration of gels formed with the low Mw alginate could be raised to further increase the moduli of gels without significantly deteriorating the viability of immobilized cells. This was likely due to the limited increase in the viscosity of these solutions. This material design approach may be useful with a variety of synthetic or naturally occurring block copolymers used to immobilize cells.

Original languageEnglish (US)
Pages (from-to)4023-4029
Number of pages7
JournalBiomaterials
Volume24
Issue number22
DOIs
StatePublished - Oct 2003

Keywords

  • Alginate
  • Cell viability
  • Elastic moduli
  • Guluronic acid blocks
  • Rheological property

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering

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