title: Versatile tuning of supramolecular hydrogels through metal complexation of oxidation-resistant catechol-inspired ligands.
abstract: The mussel byssal cuticle employs DOPA-Fe3+complexation to provide strong, yet reversible crosslinking. Synthetic constructs employing this design motif based on catechol units are plagued by oxidation-driven degradation of the catechol units and the requirement for highly alkaline pH conditions leading to decreased performance and loss of supramolecular properties. Herein, a platform based on a 4-arm poly(ethylene glycol) hydrogel system is used to explore the utility of DOPA analogues such as the parent catechol and derivatives, 4-nitrocatechol (nCat) and 3-hydroxy-4-pyridinonone (HOPO), as structural crosslinking agents upon complexation with metal ions. HOPO moieties are found to hold particular promise, as robust gelation with Fe3+occurs at physiological pH and is found to be largely resistant to oxidative degradation. Gelation is also shown to be triggered by other biorelevant metal ions such as Al3+, Ga3+and Cu2+which allows for tuning of the release and dissolution profiles with potential application as injectable delivery systems.
authors.affiliation: Graduate Program in Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Menyo
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Hawker
authors.forename: J Herbert
authors.initials: JH
authors.lastname: Waite