Using Tools from Optogenetics to Create Light-Responsive Biomaterials: LOVTRAP-PEG Hydrogels for Dynamic Peptide Immobilization.

Hydrogel materials have become a versatile platform for in vitro cell culture due to their ability to simulate many aspects of native tissues. However, precise spatiotemporal presentation of peptides and other biomolecules has remained challenging. Here we report the use of light-sensing proteins (LSPs), more commonly used in optogenetics research, as light-activated reversible binding sites within synthetic poly(ethylene glycol) (PEG) hydrogels.

Cell-Compatible, Site-Specific Covalent Modification of Hydrogel Scaffolds Enables User-Defined Control over Cell-Material Interactions.

SpyCatcher, a 15 kDa protein domain that spontaneously forms a site-specific covalent bond with the 13 amino acid peptide SpyTag, was used to covalently link a model recombinant protein containing a SpyCatcher domain and the adhesive ligand Arg-Gly-Asp-Ser (RGDS) (RGDS-SC) into SpyTag-containing poly(ethylene glycol) (PEG) hydrogels. This new strategy for covalent immobilization of proteins or peptides provides an easy and gentle mechanism for biochemical modification of hydrogels. Labeling efficiency was approximately 100% when soluble RGDS-SC was applied to SpyTag-containing hydrogels at a 1:1 molar ratio.