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Spatial and Temporal Control of 3D Hydrogel Viscoelasticity through Phototuning
Philip Crandell1, Ryan Stowers1,2
1Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, California 93016, United States.
ACS Biomaterials Science & Engineering
|November 29, 2023
Summary
Researchers developed a light-triggered method to control hydrogel stress relaxation rates without changing stiffness. This allows dynamic tuning of the cellular microenvironment, influencing cell behavior and enabling new tissue engineering strategies.
Area of Science:
- Biomaterials Science
- Cellular Mechanobiology
- Tissue Engineering
Background:
- Cellular functions like migration and differentiation are regulated by the mechanical properties of the extracellular matrix (ECM).
- While ECM elastic modulus and stress relaxation are known to affect cells, dynamically tuning stress relaxation rates in biomaterials remains challenging.
- Physiological processes involve dynamic changes in ECM mechanical properties over time and space.
Purpose of the Study:
- To develop a method for dynamically tuning hydrogel stress relaxation rates independently of elastic modulus.
- To investigate cellular responses to controlled changes in hydrogel stress relaxation.
- To explore the application of this technique in creating spatially patterned mechanical environments for cells.
Main Methods:
- A light-triggered tethering strategy using poly(ethylene glycol) and alginate was employed to modulate hydrogel properties.
- Hydrogel stress relaxation rates were tuned spatiotemporally using light without altering the elastic modulus.
- Cellular responses, including morphology and proliferation, were assessed in response to dynamic stress relaxation changes.
Main Results:
- The developed method successfully tuned hydrogel stress relaxation rates dynamically in time and space.
- Elastic modulus remained constant while stress relaxation rates were altered.
- Cells exhibited distinct morphological and proliferation responses to dynamic stress relaxation rate variations.
- Spatial patterns of stress relaxation rates were successfully generated within 3D hydrogels.
Conclusions:
- This light-based technique offers precise, user-directed control over 3D hydrogel stress relaxation rates.
- The ability to independently tune stress relaxation provides a powerful tool for studying dynamic ECM mechanobiology.
- This approach has significant potential for mimicking physiological dynamic environments and guiding cell fate in tissue engineering.
