Picture: UVA Engineering
A team at the University of Virginia has developed a new 3D-printable hydrogel based on polyethylene glycol (PEG) that can be stretched significantly while remaining compatible with the body’s own cells. The work of the Soft Biomatter Laboratory led by Liheng Cai, published in Advanced Materials, targets applications in regenerative medicine, drug depots and, in the long term, battery technology.
PEG is well established in biomedicine, but until now it has mostly been used as a brittle, crystalline network that can only be deformed to a limited extent. The group around first author Baiqiang Huang fundamentally changes the architecture of the material: instead of linear chains, the researchers rely on so-called “foldable bottlebrush” polymers. In these, the macromolecules carry flexible side chains that can fold up like an accordion and unfold again under tensile load. This creates a network that combines high strength with pronounced elasticity.
“Our group discovered this polymer and used this architecture to show any materials made this way are very stretchable,” Liheng Cai said. “We can change the shape of the UV lights to create so many complicated structures,” Huang said.
From a technical standpoint, the key is that this architecture can be created from a precursor mixture using UV light within a few seconds. The material can be structured layer by layer and is therefore suitable for 3D printing complex geometries. Depending on the processing conditions, soft hydrogels or solvent-free elastomers can be produced that can be tailored to different requirements, for example for organ replacement structures or flexible implants.
In cell cultures, the team showed that the new PEG networks are cell-compatible and can therefore be considered as scaffold materials for artificial tissue.
“This property highlights the new material as a promising high-performance solid-state electrolyte for advanced battery technologies,” Cai said. “Our team continues to explore potential extensions of the research in solid-state battery technologies.”
The group sees another field of application in solid polymer electrolytes. Compared with established materials, the system showed greater stretchability while also offering increased conductivity at room temperature. For additive manufacturing, this approach means that mechanically robust, biocompatible and at the same time conductive structures can be specifically printed – a combination that is equally attractive for future implants and energy storage devices.
