953: RAFT Polymer-Based Piezoionic Hydrogels for Skeletal Muscle Engineering

This study aims to connect piezoionics and muscle tissue engineering, exploring hydrogel applications in ionic environments and their effects on cellular behaviour in muscle regeneration. Muscle tissue engineering aims to create functional constructs for damaged tissues, often mimicking natural tissue properties like conductivity.[1] Traditional methods using metallic and carbon particles pose challenges such as inhomogeneity, manufacturing issues, and toxicity.

This work employs ion transport for precise control of hydrogel properties, avoiding particles to increase conductivity. Additionally, it explores the piezoionic potential of ionic hydrogels, which generate electricity through mechanical deformation, holding promise in tissue engineering. [2]

Novel RAFT copolymers were developed using neutral, cationic, and thiolated monomers, allowing independent tuning of crosslinking and charge density. Cationic photo-crosslinkable RAFT polymers were synthesized and used as thiol crosslinkers for gelatin-norbornene, forming hybrid ionic hydrogels upon photo-crosslinking. By varying the neutral:cationic:thiol ratio, crosslinking and charge density can be independently tuned. The hydrogels' storage/loss modulus, mass swelling ratio, gel point, and gel fraction were characterized.

At constant crosslinking density, the storage modulus remained unchanged, but swelling decreased significantly with increasing cationic charge density. Adjusting the thiol content allowed fine-tuning the storage moduli, while modifying the cationic content altered the mass swelling ratio. All gel fractions exceeded 95%, indicating efficient crosslinking due to the thiol-ene photo-crosslinking mechanism.

This three-component RAFT copolymer approach allows independent control of charge and crosslinking density, offering new insights into ionic conductivity and piezoionic potential in hydrogels, advancing muscle tissue engineering.