Comandini, G. | bioRxiv Science

bioRxiv2025

Tunable porosity in a hydrogel with extreme vibration damping properties

We have developed hydrogel systems with tunable porosity through dialysis casting by varying alginate and poloxamer compositions from 0% to 10%. These gels feature diverse porosity topologies, yielding loss factors between 16% and 29% in the 50 Hz to 300 Hz frequency range. The dynamic modulus shows a remarkable increase of over an order of magnitude, reaching approximately 3 MPa compared to the static modulus. Vibration transmissibility tests and dynamic mechanical analysis reveal that the poroelastic and pneumatic-like effects from the tunable porous structures contribute significantly to this damping effect. Furthermore, these hydrogels are biosourced and biodegradable, providing a sustainable alternative to conventional fossil-based damping materials.

bioengineering↗

bioRxiv2024

Coagulative Granular Hydrogels with an Enzyme Catalyzed Fibrin Network for Endogenous Tissue Regeneration

Granular hydrogels, composed of densely packed microgels, are an emerging class of injectable microporous scaffolds that provide interstitial porosity for endogenous cell recruitment and tissue repair. However, weak bonding interactions between constituent microgels compromises the mechanical integrity of these biomaterials, limiting their scope and effectiveness for in vivo application where structural support is required. To address this challenge, we introduce a new bioinspired stabilization method and a novel class of regenerative biomaterial: coagulative granular hydrogels, assembled from thrombin-functionalized gelatin methacryloyl microgels. The surface-bound thrombin is enzymatically active and catalyzes the conversion of fibrinogen into a fibrin hydrogel that extends throughout the interstitial voids of the granular hydrogel. This secondary network acts as a biological glue to stabilize the granular hydrogel, yielding shear and compressive properties comparable to bulk hydrogel controls. Furthermore, the interstitial fibrin network provides a favorable microenvironment for the adhesion, proliferation, and invasion of endothelial cells, highlighting the potential of the biomaterial to support endogenous tissue repair. This innovative stabilization mechanism provides a responsive biomaterial system, and future studies will seek to explore how the biomaterial is annealed in vivo by the presence of blood plasma fibrinogen.

bioengineering↗