Adding Dynamic Biomolecule Signaling to Hydrogel Systems via Tethered Photolabile Cell-Adhesive Proteins

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Molecular Biology

Background:

• Sequential biochemical signaling is crucial for tissue regeneration, but current in vitro models struggle to replicate this dynamism.
• Existing synthetic tissue culture constructs lack the ability to sequentially add and remove signaling molecules, limiting their accuracy.

Purpose of the Study:

• To develop a genetically encoded method for reversible biochemical signaling within poly(ethylene glycol) (PEG)-based hydrogels.
• To create a more accurate in vitro model for studying tissue regeneration by recapitulating transient signaling events.

Main Methods:

• Engineered a recombinant protein linking a SpyCatcher domain, a cell-adhesive RGDS peptide, and a light-cleavable PhoCl domain.
• Utilized SpyTag-SpyCatcher isopeptide bonding to anchor the protein to PEG-matrices, presenting RGDS ligands to cells.
• Applied 405 nm light to cleave the PhoCl domain, releasing RGDS peptides and enabling reversible cell adhesion.

Main Results:

• Demonstrated reversible adhesion of 3T3 fibroblasts to PEG-hydrogel surfaces in 2D culture (73.36% cell removal).
• Achieved temporal control over cell spreading in 3D culture within cell-degradable PEG-hydrogels.
• Successfully presented dynamic signaling events to cells in a controlled, extracellular matrix-mimetic environment.

Conclusions:

• The developed light-cleavable system enables precise temporal control over cell adhesion and signaling in biomaterial matrices.
• This technology offers a powerful tool for advancing in vitro modeling of complex tissue regeneration processes.
• The system enhances the accuracy of reductionist models for studying endogenous tissue behavior and therapeutic outcomes.