Gelatin-Based Functional Biogels With Mechanical Tunability via Pioneering Design of Co-Polymerizable Deep Eutectic Solvents.

Eutectic biogels, combining deep eutectic solvents (DES) with biopolymer networks, are highly promising for advanced applications. However, the design of co-polymerizable DES (cPDES) remains largely unexplored for novel biogels. Herein, we constructed an innovative cPDES by strategically selecting 2-(acryloyloxy)ethyl trimethyl ammonium chloride as the polymerizable hydrogen bond acceptor and itaconic acid as the polymerizable hydrogen bond donor. By employing this cPDES as a functional solvent, gelatin as the matrix, and glycerol as a regulator, a multifunctional biogel (denoted as BioGel-PGG) with a unique polymeric network integrating an enhanced non-covalent network with a dual network induced by the copolymerization of DES was developed, which showed widely tunable mechanical properties (e.g., elastic modulus: 0.03-55.52 MPa, toughness: 0.05-14.03 MJ/m3). Furthermore, BioGel-PGG demonstrates multifunctionality integration, including strong skin adhesion (3.20 N/cm), good conductivity, environmental stability, recyclability, and biodegradability. Epidermal bioelectrodes based on BioGel-PGG enabled high-quality monitoring of electrophysiological signals. This work opens a new avenue for designing high-performance eutectic biogels by exploiting cPDES.