PH-based regulation of hydrogel mechanical properties through mussel-inspired chemistry and processing

Devin G. Barrett, Dominic E. Fullenkamp, Lihong He, Niels Holten-Andersen, Ka Yee C. Lee, Phillip B. Messersmith*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

203 Scopus citations


The mechanical holdfast of the mussel, the byssus, is processed at acidic pH yet functions at alkaline pH. Byssi are enriched in Fe3+ and catechol-containing proteins, species with chemical interactions that vary widely over the pH range of byssal processing. Currently, the link between pH, Fe3+-catechol reactions, and mechanical function is poorly understood. Herein, it is described how pH influences the mechanical performance of materials formed by reacting synthetic catechol polymers with Fe 3+. Processing Fe3+-catechol polymer materials through a mussel-mimetic acidic-to-alkaline pH change leads to mechanically tough materials based on a covalent network fortified by sacrificial Fe 3+-catechol coordination bonds. These findings offer the first direct evidence of Fe3+-induced covalent cross-linking of catechol polymers, reveal additional insight into the pH dependence and mechanical role of Fe3+-catechol interactions in mussel byssi, and illustrate the wide range of physical properties accessible in synthetic materials through mimicry of mussel-protein chemistry and processing. Novel bioinspired and tough hydrogels are designed by regulating the pH of the reaction between catechol-terminated poly(ethylene glycol) (PEG) and Fe3+. A covalently cross-linked network is fortified with a series of coordination bonds, which act as sacrificial and reversible interactions to dissipate energy during deformation. These hydrogels represent a novel class of mussel-mimetic biomaterials inspired in both content and processing.

Original languageEnglish (US)
Pages (from-to)1111-1119
Number of pages9
JournalAdvanced Functional Materials
Issue number9
StatePublished - Mar 6 2013


  • biomimetics
  • hydrogels
  • polymeric materials
  • structure-property relationships

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Chemistry(all)
  • Materials Science(all)


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