Hydrogels with multiple RGD presentations increase cell adhesion and spreading

Area of Science:

• Biomaterials Science
• Cell Biology
• Tissue Engineering

Background:

• Replicating complex cell-matrix interactions in engineered tissues is crucial for cell culture and disease modeling.
• Cells interact with their matrix via integrins, forming dynamic adhesions that involve ligand mobility and force exertion.
• Current hydrogel platforms struggle to independently control mechanical properties and adhesion ligand presentation.

Purpose of the Study:

• To develop a dual-network hydrogel platform enabling independent control over matrix viscoelasticity and adhesion ligand mobility.
• To investigate how varying ligand mobility and mechanical properties influence endothelial cell adhesion, spreading, and matrix interactions.
• To provide insights for designing advanced biomaterials that better mimic physiological cell-matrix adhesions.

Main Methods:

• Fabrication of interpenetrating polymer networks using poly(ethylene glycol) (PEG) and peptide amphiphiles (PA).
• Tuning hydrogel viscoelasticity by adjusting the PEG and PA network composition.
• Independent control of arginine-glycine-aspartic acid (RGD) ligand mobility by attaching them to covalent (PEG) or dynamic (PA) networks, or both.

Main Results:

• Hydrogel viscoelasticity was successfully tuned by modulating the composition of the dual-network system.
• Endothelial cell adhesion formation and spreading were maximized in soft gels presenting RGD ligands on both covalent and dynamic networks.
• Optimal cell function required simultaneous engagement with both mobile and force-resistant adhesion ligand presentations, independent of matrix viscoelasticity.

Conclusions:

• The dual-network hydrogel platform allows independent tuning of mechanical properties and ligand mobility, crucial for biomimicry.
• Endothelial cells require a combination of mobile and stable adhesion sites to optimally form adhesions and spread.
• These findings offer a design strategy for advanced hydrogels that more accurately recapitulate in vivo cell-matrix interactions for tissue engineering and research.