Metal-Coordination Crosslinked Polymer Materials with Programmable Viscoelastic Material Functions Controlled by Longwave UV Light

Applications

Four-armed polyethylene glycol (PEG) molecules with terminal histidine groups are able to crosslink to form hydrogels when combined with metal ions such as Cobalt (Co), Copper (Cu), and Nickel (Ni). These inventors have improved upon this 4PEG-His-Metal hydrogel technology by including the UV sensitive photoinitiator lithium acylphosphinate (LAP) in the hydrogels. LAP generates free radicals upon exposure to UV that can oxidize or reduce the metal centers of the 4PEG-His-Metal crosslinks. Using different metals can result in hydrogels that solidify or loosen upon UV exposure. Additionally, combining different metals in various ratios can produce a wide array of hydrogels with tunable viscoelastic attributes. This system allows the production of “designer” hydrogels with very precisely defined viscoelastic properties.

Problem Addressed

Hydrogel materials can have a wide array of physical properties that make them useful in many diverse fields ranging from drug delivery and tissue engineering to soft adhesive design. Hydrogel engineering has thus far been limited by the tunability of covalently linked hydrogels, and there remains a need for hydrogels with improved strength, unique viscoelastic properties, and stimuli responsiveness. These inventors describe a set of metal crosslinked hydrogels that have tunable viscoelastic properties and can additionally switch properties upon exposure to UV light.

Advantages

• UV inducible switching of viscoelastic properties
• “Designer” hydrogels with precise characteristics and UV responses 

Publications

Grindy, S. C., & Holten-Andersen, N. (2017). Bio-inspired metal-coordinate hydrogels with programmable viscoelastic material functions controlled by longwave UV light. Soft Matter, 13, 4057-4065. https://doi.org/10.1039/C7SM00617A.