Squid tissues and chemistry combine for versatile hydrogels

Squid tissues and chemistry combine for versatile hydrogels

Squid tissues and chemistry combine for versatile hydrogels

The new squid/synthetic polymer dual network gel developed in this study. Credit: Tasuku Nakajima

Researchers at Hokkaido University in Japan have combined natural squid tissues with synthetic polymers to develop a strong and versatile hydrogel that mimics many of the unique properties of biological tissues. Hydrogels are polymer networks that contain large amounts of water and are being explored for many uses, including medical prosthetics, soft robotic components, and new sensor systems.

The Hokkaido team reports their contribution to this fast-moving area of ​​research in the journal. NPG Asia Materials.

Natural biological tissues exhibit unique properties essential to their functions, which researchers seek to replicate in hydrogels. Muscles, for example, in addition to strength and flexibility, have physical properties that vary in different directions and are built from a hierarchy of structures that work together. Bones and blood vessels also display these characteristics, known as hierarchical anisotropy.

Unlike the natural tissues that researchers want to mimic, most synthetic hydrogels have uniform properties in all directions and are structurally weak.

Squid tissues and chemistry combine for versatile hydrogels

The squid mantle is cut into thin rectangles (left) and dipped into a polyacrylamide (AAm) solution, which enters the mantle (middle). Heating at 56°C for 12 hours resulted in the squid synthetic DN gel (right). Credit: Shou Ohmura, et al. Materials from NPG Asia. January 20, 2023

“By combining the properties of squid-derived tissues with synthetic polymers, we have demonstrated a hybrid strategy that serves as a general method for preparing hydrogels with useful hierarchical anisotropy and also toughness,” says polymer scientist Tasuku Nakajima of the University team. from Hokkaido.

The manufacturing process begins with the commercially available frozen squid mantle, the main outer part of a squid. In live squid, the mantle expands to bring water into the body, and then contracts strongly to expel water as a squirt. This ability depends on the anisotropic muscles within the connective tissue of the squid. The researchers took advantage of the molecular arrangements within this natural system to build their bio-mimicking gel.

When a notch is cut into the squid synthetic polymer double net gel and gradually stretched, the rupture does not cut directly through the composite because the muscle fibers suppress crack propagation. Credit: Shou Ohmura, et al. Materials from NPG Asia. January 20, 2023

Chemical and heat treatment of thin slices of thawed squid tissue mixed with polyacrylamide polymer molecules initiated the formation of the crosslinked hybrid hydrogel. It has what is known as a double mesh structure, with the synthetic polymer mesh embedded and bound within the more natural muscle fiber mesh derived from the squid mantle.

“The DN gel we synthesized is much stronger and more elastic than the natural mantle of the squid,” explains Professor Jian Ping Gong, who led the team. “The unique composite structure also makes the material impressively resistant to fracture, four times stronger than the original material.”

The current proof-of-concept work should be just the beginning to explore many other hybrid hydrogels that could exploit the unique properties of other natural systems. Jellyfish have already been used as a source material for simpler single-network hydrogels, making them an obvious next choice for exploring hybrid double-network options.

When a notch is cut in the squid synthetic polymer double-network gel and stretched with a 500-gram weight, it does not fracture. Credit: Shou Ohmura, et al. Materials from NPG Asia. January 20, 2023

“Potential applications include load-bearing artificial fibrous tissues, such as artificial ligaments and tendons, for medical use,” says Gong. Further work by the team will explore the biocompatibility of the gels and investigate options for making a range of gels suitable for different uses.

More information:
Squid Dual Net Gel/Synthetic Polymer: Elaborate anisotropy and excellent fracture toughness, NPG Asia Materials (2023). DOI: 10.1038/s41427-022-00454-9

Provided by Hokkaido University

Citation: Combining Squid Tissues and Chemistry for Versatile Hydrogels (Jan 19, 2023) Accessed 19 Jan 2023 at https://phys.org/news/2023-01-squid-tissues-chemistry-combine-versatile. html

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